medium access control - michigan state universityglxing/824/slides/mac-cse824.pdfpropagation delay...

Medium

Access Control

5 D

ata

Lin

k La

yer

5-1

All m

ate

rial co

pyrigh

t 19

96

-20

09JF

Kuro

se and KW

Ross A

ll Righ

ts Re

served

Link Layer

Introduction and services

M

ultiple access protocols

Ethernet

Wireless links

5 D

ata

Lin

k La

yer

5-2

W

ireless LAN

s (80211)

Link Layer Services

__________ ___________

encapsulate datagram into fram

e adding header trailer

channel access if shared medium

ldquoM

ACrdquo

addresses used in frame headers to identify src dest

bulldifferent from

IP address

5 D

ata

Lin

k La

yer

5-3

______________________

seldom used on low bit-error link (fiber som

e twisted pair)

wireless links high error ratesbull

Q why both link-level and end-end reliability

Link Layer Services (more)

_____________

pacing between adjacent sending and receiving nodes

_____________

errors caused by signal attenuation noise d

f

5 D

ata

Lin

k La

yer

5-4

receiver detects presence of errors

bullsignals sender for retransm

ission or drops frame

_____________

receiver identifies and correctsbit error(s) without

resorting to retransmission

half-duplex and full-duplex

with half duplex nodes at both ends of link can transmit

but not at same tim

e

Where is the link layer im

plemented

in each and every host

link layer im

plemented in

ldquoadaptorrdquo(aka network

interface cardN

IC)

Ethernet card PCMCI

cpu

me

mo

ry

ho

st sche

ma

tic

ap

plica

tiontra

nsp

ort

network

link

5 D

ata

Lin

k La

yer

5-5

card 80211 card

implem

ents link physical layer

attaches into hostrsquos system

buses

combination of

hardware software firm

ware

contro

ller

ph

ysical

transmission

host bus (eg P

CI)

ne

two

rk ad

ap

ter

card

link

linkp

hysica

l

Multiple A

ccess Links and ProtocolsTwo types of ldquolinksrdquo

point-to-point

PPP for dial-up access

point-to-point link between Ethernet switch and host

broadcast(shared wire or m

edium)

old-fashioned Ethernet

hb

d fb

5 D

ata

Lin

k La

yer

5-6

upstream

hybrid fiber coax

________________

shared wire (eg cabled Ethernet)

shared RF(eg 80211 W

iFi)shared RF(satellite)

humans at a

cocktail party (shared air acoustical)

Multiple A

ccess protocols

single shared broadcast channel

two or more sim

ultaneous transmissions by nodes

interference

collisionif node receives two or m

ore signals at the same tim

em

ultiple access protocol

5 D

ata

Lin

k La

yer

5-7

distributed algorithm

that determines how nodes

share channel ie determine when node can transm

it

comm

unication about channel sharing must use channel

itself

no out-of-band channel for coordination

MA

C Protocols a taxonomy

Three broad classes

_______________

divide channel into smaller ldquopiecesrdquo

(time slots

frequency code)

allocate piece to node for exclusive use

5 D

ata

Lin

k La

yer

5-8

________________

channel not divided allow collisions

ldquorecoverrdquofrom

collisions

_________________

nodes take turns but nodes with more to send can take

longer turns

Channel Partitioning MA

C protocols TDM

A

TDM

A tim

e division multiple access

access to channel in rounds

each station gets fixed length slot (length = pkt trans tim

e) in each round

unused slots go idle

5 D

ata

Lin

k La

yer

5-9


exam

ple 6-station LAN

134 have pkt slots 256 idle 1

34

13

4

6-slotfram

e


C protocols FDM

A

FDM

A frequency division m

ultiple access

channel spectrum divided into frequency bands

each station assigned fixed frequency band

unused transm

ission time in frequency bands go idle

exam

ple 6-station LAN

13

4 have pkt frequency

5 D

ata

Lin

k La

yer

5-1

0

exam

ple 6-station LAN

134 have pkt frequency bands 256 idle

frequency bands

FDM

cable

Random A

ccess Protocols

W

hen node has packet to send

transmit at full channel data rate R

no a prioricoordination am

ong nodes

two or more transm

itting nodes ldquocollision

rdquo

random access M

AC protocolspecifies

5 D

ata

Lin

k La

yer

5-11

random

access MA

C protocolspecifies

how to detect collisions

how to recover from collisions (eg via delayed

retransmissions)

Exam

ples of random access M

AC protocols

_____________________

_____________________

CSMA

(Carrier Sense Multiple A

ccess)

CSMA

listen before transmit

If channel sensed idle transmit entire fram

e

If channel sensed busy defer transmission 5

Da

taL

ink L

aye

r5

-12

hum

an analogy donrsquot interrupt others

CSMA

collisionscollisions can

still occurpropagation delay m

eans two nodes m

ay not heareach otherrsquos transm

ission

collision

5 D

ata

Lin

k La

yer

5-1

3

entire packet transmission

time wasted

noterole of distance amp propagation delay in determ

ining collision probability

CSMA

CD (Collision D

etection)CSM

ACD

carrier sensing deferral as in CSMA

collisions detected

within short time

colliding transm

issions aborted reducing channel wastage

collision detection

5 D

ata

Lin

k La

yer

5-1

4

collision detection

easy in wired LAN

s measure signal strengths

compare transm

itted received signals

difficult in wireless LAN

s received signal strength overwhelm

ed by local transmission strength

hum

an analogy the polite conversationalist

ldquoTaking TurnsrdquoM

AC protocols

channel partitioning MA

C protocols

share channel efficientlyand fairly

at high load

inefficient at low load delay in channel access 1N

bandwidth allocated even if only 1 active node

5 D

ata

Lin

k La

yer

5-1

5

node Random

access MA

C protocols

efficient at low load single node can fully utilize channel

high load collision overhead

ldquotaking turnsrdquoprotocols

look for best of both worlds

Summ

ary of MA

C protocols

channel partitioningby tim

e frequency or code

Time D

ivision Frequency Division

random

access (dynamic)

A

LOH

A S-A

LOH

A CSM

A CSM

ACD

carrier sensing easy in som

e technologies (wire) hard in

5 D

ata

Lin

k La

yer

5-1

6


e technologies (wire) hard in others (wireless)

CSM

ACD

used in Ethernet

CSMA

CA used in 80211

taking turns

polling from central site token passing

Bluetooth FD

DI IBM

Token Ring

Ethernetldquodom

inantrdquowired LA

N technology

cheap $20 for N

IC

first widely used LAN

technology

simpler cheaper than token LA

Ns and A

TM

kept up with speed race 10 Mbps ndash

10 Gbps

5 D

ata

Lin

k La

yer

5-1

7

pp

pp

p

Metcalfe

rsquos Ethernetsketch

Star topology

bus topology popular through mid 90s

all nodes in sam

e collision domain (can collide with each

other)

today star topology prevails

active switchin center

each ldquospoke

rdquoruns a (separate) Ethernet protocol (nodes

do not collide with each other)

5 Da

taLink Layer

5-18

switch

bus coaxial cablestar

Ethernet Unreliable connectionless

connectionlessN

o handshaking between sending and receiving N

ICs

unreliablereceiving NIC doesn

rsquot send acks or nacks to sending N

IC

stream of datagram

s passed to network layer can have gaps

5 D

ata

Lin

k La

yer

5-1

9

stream

of datagrams passed to network layer can have gaps

(missing datagram

s)

gaps will be filled if app is using TCP

otherwise app will see gaps

Ethernetrsquos MA

C protocol unslotted CSMA

CD

Ethernet CSMA

CD algorithm

1 NIC receives datagram

from

network layer creates fram

e2 If N

IC senses channel idle starts fram

e transmission

If NIC senses channel

4 If NIC detects another

transmission while

transmitting aborts and

sends jam signal

5 After aborting N

IC enters exponential

5 D

ata

Lin

k La

yer

5-2

0


busy waits until channel idle then transm

its3 If N

IC transmits entire

frame without detecting

another transmission N

IC is done with fram

e

enters exponential backoff after m

th collision N

IC chooses K at random

from

012hellip2m-1N

IC waits K512 bit tim

es returns to Step 2

Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all

other transmitters are

aware of collision 48 bitsBit tim

e1 microsec for 10

Mbps Ethernet

for K=1023 wait time is

about 50 msec

Exponential Backoff

Goal adapt retransmission

attempts to estim

ated current load

heavy load random wait

will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec

first collision choose K from

01 delay is K512 bit transm

ission times

after second collision choose K from

0123hellip

after ten collisions choose K from

01234hellip1023

Elements of a wireless network

network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure

wireless does not always m

ean mobility


network

base station

typically connected to wired network

relay -responsible for sending packets between wired network and wireless

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23

infrastructurehost(s) in its ldquoareardquo

eg cell towers 80211 access points


network

wireless link

typically used to connect m

obile(s) to base station

also used as backbone link

m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access

protocol coordinates link access

various data rates transm

ission distance

Characteristics of selected wireless link standards

4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode

base station connects m

obiles into wired network

handoff m

obile changes base station providing connection

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations

nodes can only transm

it to other nodes within link coverage

nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them

selves into a network route am

ong them

selves

Wireless network taxonom

y

single hopm

ultiple hops

infrastructure(eg APs)

host connects to base station (W

iFiW

iMAX cellular)

which connects to larger Internet

host may have to

relay through severalwireless nodes to connect to larger

Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet

no base station noconnection to larger Internet (Bluetooth

ad hoc nets)

Internet mesh net

no base station noconnection to larger

Internet May have to

relay to reach other a given wireless node

MAN

ET VANET

Wireless Link Characteristics

Differences from

wired link hellip

_____________radio signal attenuates as it propagates through m

atter (path loss)

_______________standardized wireless network frequencies (eg 24 GH

z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg

yother devices (eg phone) devices (m

otors) interfere as well

_______________radio signal reflects off objects ground arriving ad destination at slightly different tim

es

hellip make com

munication across (even a point to point)

wireless link much m

ore ldquodifficultrdquo

Wireless network characteristics

Multiple wireless senders and receivers create additional problem

s (beyond multiple access)

B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other

A C can not hear each otherm

eans A C unaware of their interference at B

space

80211 LAN

architecture

wireless host com

municates

with base station

_______________

_____________________(aka ldquocellrdquo) in infrastructure m

ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts

access point (AP) base station

ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP

80211 Channels association

80211b 24GH

z-2485GHz spectrum

divided into ________ channels at different frequencies

AP adm

in chooses frequency for AP

interference possible channel can be sam

e as that chosen by neighboring A

P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP

IEEE 80211 multiple access

avoid collisions 2

+nodes transmitting at sam

e time

80211 CSM

A -

sense before transmitting

donrsquot collide with ongoing transm

ission by other node

80211 nocollision detection

difficult to receive (sense collisions) when transm

itting due to weak received signals (fading)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)

canrsquot sense all collisions in any case hidden term

inal fading

goal avoid collisionsCSMA

C(ollision)A(voidance)

AB

CA

BC

Arsquos signalstrength

space

Crsquos signalstrength

IEEE 80211 MA

C Protocol CSMA

CA

80211 sender1 if sense channel idle

for DIFS

thentransm

it entire frame (no CD

)2 if

sense channel busy thenstart random

backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34

timer counts down while channel idle

transmit when tim

er expiresif no A

CK increase random backoff

interval repeat 280211 receiver-

if frame received O

Kreturn A

CK after SIFS (ACK needed due

to hidden terminal problem

)

data

SIFS

ACK

Avoiding collisions (m

ore)idea

allow sender to ldquoreserverdquo channel rather than random

access of data frames avoid collisions of long data fram

es

sender first transmits sm

allrequest-to-send (RTS) packets to BS using CSM

A

RTSs may still collide with each other (but theyrsquore short)

BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35

BS broadcasts clear-to-send CTS in response to RTS

CTS heard by all nodes

sender transmits data fram

e

other stations defer transmissions

avoid data frame collisions com

pletely using sm

all reservation packets

Collision Avoidance RTS-CTS exchange

APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time

80211 advanced capabilitiesRate Adaptation

base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37

modulation technique)

as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER

increase as node moves

away from base station

2 When BER becom

es too high switch to lower transm

ission rate but with lower BER

80211 advanced capabilitiesPower M

anagement

node-to-AP ldquoI am

going to sleep until next beacon fram

erdquo

AP knows not to transmit fram

es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38

node wakes up before next beacon fram

e

beacon frame contains list of m

obiles with AP-to-m

obile frames waiting to be sent

node will stay awake if AP-to-m

obile frames

to be sent otherwise sleep again until next beacon fram

e

Mradius ofcoverage

SP

P

80215 personal area network

less than 10 m diam

eter

replacement for cables

(mouse keyboard

headphones)

ad hoc no infrastructure

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device

Parked device (inactive)

P

m

asterslaves

slaves request permission to

send (to master)

m

aster grants requests

80215 evolved from

Bluetooth specification

24-25 GHz radio band

up to 721 kbps

Wireless m

obility impact on higher layer protocols

logically im

pact shouldbe m

inimal hellip

best effort service m

odel remains unchanged

TCP and U

DP can (and do) run over wireless m

obile

hellip but performance-wise

packet lossdelay due to bit-errors (discarded

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40

packet lossdelay due to bit-errors (discarded packets delays for link-layer retransm

issions) and handoff

TCP interprets loss as congestion will decrease congestion window un-necessarily

delay im

pairments for real-tim

e traffic

limited bandwidth of wireless links

Link Layer

Introduction and services

M

ultiple access protocols

Ethernet

Wireless links

5 D

ata

Lin

k La

yer

5-2

W

ireless LAN

s (80211)

Link Layer Services

__________ ___________




ldquoM

ACrdquo


bulldifferent from

IP address

5 D

ata

Lin

k La

yer

5-3

______________________


e twisted pair)




_____________


_____________


f

5 D

ata

Lin

k La

yer

5-4




_____________





but not at same tim

e


plemented


link layer im

plemented in


interface cardN

IC)

Ethernet card PCMCI

cpu

me

mo

ry

ho

st sche

ma

tic

ap

plica

tiontra

nsp

ort

network

link

5 D

ata

Lin

k La

yer

5-5

card 80211 card

implem



buses

combination of


ware

contro

ller

ph

ysical

transmission

host bus (eg P

CI)

ne

two

rk ad

ap

ter

card

link

linkp

hysica

l

Multiple A


point-to-point




edium)


hb

d fb

5 D

ata

Lin

k La

yer

5-6

upstream

hybrid fiber coax

________________




humans at a


Multiple A

ccess protocols


two or more sim


interference



em


5 D

ata

Lin

k La

yer

5-7




it

comm


itself


MA


Three broad classes

_______________


(time slots

frequency code)


5 D

ata

Lin

k La

yer

5-8

________________



collisions

_________________


longer turns


C protocols TDM

A

TDM

A tim




e) in each round


5 D

ata

Lin

k La

yer

5-9


exam

ple 6-station LAN


34

13

4

6-slotfram

e


C protocols FDM

A

FDM


ultiple access



unused transm


exam

ple 6-station LAN

13


5 D

ata

Lin

k La

yer

5-1

0

exam

ple 6-station LAN


frequency bands

FDM

cable

Random A

ccess Protocols

W




ong nodes

two or more transm


rdquo

random access M


5 D

ata

Lin

k La

yer

5-11

random

access MA

C protocolspecifies



retransmissions)

Exam


AC protocols

_____________________

_____________________

CSMA


ccess)

CSMA



e


Da

taL

ink L

aye

r5

-12

hum


CSMA



eans two nodes m


ission

collision

5 D

ata

Lin

k La

yer

5-1

3


time wasted



CSMA

CD (Collision D

etection)CSM

ACD


collisions detected

within short time

colliding transm


collision detection

5 D

ata

Lin

k La

yer

5-1

4

collision detection

easy in wired LAN


compare transm





hum



AC protocols


C protocols


at high load



5 D

ata

Lin

k La

yer

5-1

5

node Random

access MA

C protocols





Summ

ary of MA

C protocols


e frequency or code

Time D


random

access (dynamic)

A

LOH

A S-A

LOH

A CSM

A CSM

ACD



5 D

ata

Lin

k La

yer

5-1

6



CSM

ACD

used in Ethernet

CSMA

CA used in 80211

taking turns


Bluetooth FD

DI IBM

Token Ring

Ethernetldquodom

inantrdquowired LA

N technology

cheap $20 for N

IC


technology


Ns and A

TM


10 Gbps

5 D

ata

Lin

k La

yer

5-1

7

pp

pp

p

Metcalfe


Star topology


all nodes in sam


other)



each ldquospoke



5 Da

taLink Layer

5-18

switch



connectionlessN


ICs



IC

stream of datagram


5 D

ata

Lin

k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic


Link Layer Services

__________ ___________




ldquoM

ACrdquo


bulldifferent from

IP address

5 D

ata

Lin

k La

yer

5-3

______________________


e twisted pair)




_____________


_____________


f

5 D

ata

Lin

k La

yer

5-4




_____________





but not at same tim

e


plemented


link layer im

plemented in


interface cardN

IC)

Ethernet card PCMCI

cpu

me

mo

ry

ho

st sche

ma

tic

ap

plica

tiontra

nsp

ort

network

link

5 D

ata

Lin

k La

yer

5-5

card 80211 card

implem



buses

combination of


ware

contro

ller

ph

ysical

transmission

host bus (eg P

CI)

ne

two

rk ad

ap

ter

card

link

linkp

hysica

l

Multiple A


point-to-point




edium)


hb

d fb

5 D

ata

Lin

k La

yer

5-6

upstream

hybrid fiber coax

________________




humans at a


Multiple A

ccess protocols


two or more sim


interference



em


5 D

ata

Lin

k La

yer

5-7




it

comm


itself


MA


Three broad classes

_______________


(time slots

frequency code)


5 D

ata

Lin

k La

yer

5-8

________________



collisions

_________________


longer turns


C protocols TDM

A

TDM

A tim




e) in each round


5 D

ata

Lin

k La

yer

5-9


exam

ple 6-station LAN


34

13

4

6-slotfram

e


C protocols FDM

A

FDM


ultiple access



unused transm


exam

ple 6-station LAN

13


5 D

ata

Lin

k La

yer

5-1

0

exam

ple 6-station LAN


frequency bands

FDM

cable

Random A

ccess Protocols

W




ong nodes

two or more transm


rdquo

random access M


5 D

ata

Lin

k La

yer

5-11

random

access MA

C protocolspecifies



retransmissions)

Exam


AC protocols

_____________________

_____________________

CSMA


ccess)

CSMA



e


Da

taL

ink L

aye

r5

-12

hum


CSMA



eans two nodes m


ission

collision

5 D

ata

Lin

k La

yer

5-1

3


time wasted



CSMA

CD (Collision D

etection)CSM

ACD


collisions detected

within short time

colliding transm


collision detection

5 D

ata

Lin

k La

yer

5-1

4

collision detection

easy in wired LAN


compare transm





hum



AC protocols


C protocols


at high load



5 D

ata

Lin

k La

yer

5-1

5

node Random

access MA

C protocols





Summ

ary of MA

C protocols


e frequency or code

Time D


random

access (dynamic)

A

LOH

A S-A

LOH

A CSM

A CSM

ACD



5 D

ata

Lin

k La

yer

5-1

6



CSM

ACD

used in Ethernet

CSMA

CA used in 80211

taking turns


Bluetooth FD

DI IBM

Token Ring

Ethernetldquodom

inantrdquowired LA

N technology

cheap $20 for N

IC


technology


Ns and A

TM


10 Gbps

5 D

ata

Lin

k La

yer

5-1

7

pp

pp

p

Metcalfe


Star topology


all nodes in sam


other)



each ldquospoke



5 Da

taLink Layer

5-18

switch



connectionlessN


ICs



IC

stream of datagram


5 D

ata

Lin

k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic



_____________


_____________


f

5 D

ata

Lin

k La

yer

5-4




_____________





but not at same tim

e


plemented


link layer im

plemented in


interface cardN

IC)

Ethernet card PCMCI

cpu

me

mo

ry

ho

st sche

ma

tic

ap

plica

tiontra

nsp

ort

network

link

5 D

ata

Lin

k La

yer

5-5

card 80211 card

implem



buses

combination of


ware

contro

ller

ph

ysical

transmission

host bus (eg P

CI)

ne

two

rk ad

ap

ter

card

link

linkp

hysica

l

Multiple A


point-to-point




edium)


hb

d fb

5 D

ata

Lin

k La

yer

5-6

upstream

hybrid fiber coax

________________




humans at a


Multiple A

ccess protocols


two or more sim


interference



em


5 D

ata

Lin

k La

yer

5-7




it

comm


itself


MA


Three broad classes

_______________


(time slots

frequency code)


5 D

ata

Lin

k La

yer

5-8

________________



collisions

_________________


longer turns


C protocols TDM

A

TDM

A tim




e) in each round


5 D

ata

Lin

k La

yer

5-9


exam

ple 6-station LAN


34

13

4

6-slotfram

e


C protocols FDM

A

FDM


ultiple access



unused transm


exam

ple 6-station LAN

13


5 D

ata

Lin

k La

yer

5-1

0

exam

ple 6-station LAN


frequency bands

FDM

cable

Random A

ccess Protocols

W




ong nodes

two or more transm


rdquo

random access M


5 D

ata

Lin

k La

yer

5-11

random

access MA

C protocolspecifies



retransmissions)

Exam


AC protocols

_____________________

_____________________

CSMA


ccess)

CSMA



e


Da

taL

ink L

aye

r5

-12

hum


CSMA



eans two nodes m


ission

collision

5 D

ata

Lin

k La

yer

5-1

3


time wasted



CSMA

CD (Collision D

etection)CSM

ACD


collisions detected

within short time

colliding transm


collision detection

5 D

ata

Lin

k La

yer

5-1

4

collision detection

easy in wired LAN


compare transm





hum



AC protocols


C protocols


at high load



5 D

ata

Lin

k La

yer

5-1

5

node Random

access MA

C protocols





Summ

ary of MA

C protocols


e frequency or code

Time D


random

access (dynamic)

A

LOH

A S-A

LOH

A CSM

A CSM

ACD



5 D

ata

Lin

k La

yer

5-1

6



CSM

ACD

used in Ethernet

CSMA

CA used in 80211

taking turns


Bluetooth FD

DI IBM

Token Ring

Ethernetldquodom

inantrdquowired LA

N technology

cheap $20 for N

IC


technology


Ns and A

TM


10 Gbps

5 D

ata

Lin

k La

yer

5-1

7

pp

pp

p

Metcalfe


Star topology


all nodes in sam


other)



each ldquospoke



5 Da

taLink Layer

5-18

switch



connectionlessN


ICs



IC

stream of datagram


5 D

ata

Lin

k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic



plemented


link layer im

plemented in


interface cardN

IC)

Ethernet card PCMCI

cpu

me

mo

ry

ho

st sche

ma

tic

ap

plica

tiontra

nsp

ort

network

link

5 D

ata

Lin

k La

yer

5-5

card 80211 card

implem



buses

combination of


ware

contro

ller

ph

ysical

transmission

host bus (eg P

CI)

ne

two

rk ad

ap

ter

card

link

linkp

hysica

l

Multiple A


point-to-point




edium)


hb

d fb

5 D

ata

Lin

k La

yer

5-6

upstream

hybrid fiber coax

________________




humans at a


Multiple A

ccess protocols


two or more sim


interference



em


5 D

ata

Lin

k La

yer

5-7




it

comm


itself


MA


Three broad classes

_______________


(time slots

frequency code)


5 D

ata

Lin

k La

yer

5-8

________________



collisions

_________________


longer turns


C protocols TDM

A

TDM

A tim




e) in each round


5 D

ata

Lin

k La

yer

5-9


exam

ple 6-station LAN


34

13

4

6-slotfram

e


C protocols FDM

A

FDM


ultiple access



unused transm


exam

ple 6-station LAN

13


5 D

ata

Lin

k La

yer

5-1

0

exam

ple 6-station LAN


frequency bands

FDM

cable

Random A

ccess Protocols

W




ong nodes

two or more transm


rdquo

random access M


5 D

ata

Lin

k La

yer

5-11

random

access MA

C protocolspecifies



retransmissions)

Exam


AC protocols

_____________________

_____________________

CSMA


ccess)

CSMA



e


Da

taL

ink L

aye

r5

-12

hum


CSMA



eans two nodes m


ission

collision

5 D

ata

Lin

k La

yer

5-1

3


time wasted



CSMA

CD (Collision D

etection)CSM

ACD


collisions detected

within short time

colliding transm


collision detection

5 D

ata

Lin

k La

yer

5-1

4

collision detection

easy in wired LAN


compare transm





hum



AC protocols


C protocols


at high load



5 D

ata

Lin

k La

yer

5-1

5

node Random

access MA

C protocols





Summ

ary of MA

C protocols


e frequency or code

Time D


random

access (dynamic)

A

LOH

A S-A

LOH

A CSM

A CSM

ACD



5 D

ata

Lin

k La

yer

5-1

6



CSM

ACD

used in Ethernet

CSMA

CA used in 80211

taking turns


Bluetooth FD

DI IBM

Token Ring

Ethernetldquodom

inantrdquowired LA

N technology

cheap $20 for N

IC


technology


Ns and A

TM


10 Gbps

5 D

ata

Lin

k La

yer

5-1

7

pp

pp

p

Metcalfe


Star topology


all nodes in sam


other)



each ldquospoke



5 Da

taLink Layer

5-18

switch



connectionlessN


ICs



IC

stream of datagram


5 D

ata

Lin

k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic


Multiple A


point-to-point




edium)


hb

d fb

5 D

ata

Lin

k La

yer

5-6

upstream

hybrid fiber coax

________________




humans at a


Multiple A

ccess protocols


two or more sim


interference



em


5 D

ata

Lin

k La

yer

5-7




it

comm


itself


MA


Three broad classes

_______________


(time slots

frequency code)


5 D

ata

Lin

k La

yer

5-8

________________



collisions

_________________


longer turns


C protocols TDM

A

TDM

A tim




e) in each round


5 D

ata

Lin

k La

yer

5-9


exam

ple 6-station LAN


34

13

4

6-slotfram

e


C protocols FDM

A

FDM


ultiple access



unused transm


exam

ple 6-station LAN

13


5 D

ata

Lin

k La

yer

5-1

0

exam

ple 6-station LAN


frequency bands

FDM

cable

Random A

ccess Protocols

W




ong nodes

two or more transm


rdquo

random access M


5 D

ata

Lin

k La

yer

5-11

random

access MA

C protocolspecifies



retransmissions)

Exam


AC protocols

_____________________

_____________________

CSMA


ccess)

CSMA



e


Da

taL

ink L

aye

r5

-12

hum


CSMA



eans two nodes m


ission

collision

5 D

ata

Lin

k La

yer

5-1

3


time wasted



CSMA

CD (Collision D

etection)CSM

ACD


collisions detected

within short time

colliding transm


collision detection

5 D

ata

Lin

k La

yer

5-1

4

collision detection

easy in wired LAN


compare transm





hum



AC protocols


C protocols


at high load



5 D

ata

Lin

k La

yer

5-1

5

node Random

access MA

C protocols





Summ

ary of MA

C protocols


e frequency or code

Time D


random

access (dynamic)

A

LOH

A S-A

LOH

A CSM

A CSM

ACD



5 D

ata

Lin

k La

yer

5-1

6



CSM

ACD

used in Ethernet

CSMA

CA used in 80211

taking turns


Bluetooth FD

DI IBM

Token Ring

Ethernetldquodom

inantrdquowired LA

N technology

cheap $20 for N

IC


technology


Ns and A

TM


10 Gbps

5 D

ata

Lin

k La

yer

5-1

7

pp

pp

p

Metcalfe


Star topology


all nodes in sam


other)



each ldquospoke



5 Da

taLink Layer

5-18

switch



connectionlessN


ICs



IC

stream of datagram


5 D

ata

Lin

k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic


Multiple A

ccess protocols


two or more sim


interference



em


5 D

ata

Lin

k La

yer

5-7




it

comm


itself


MA


Three broad classes

_______________


(time slots

frequency code)


5 D

ata

Lin

k La

yer

5-8

________________



collisions

_________________


longer turns


C protocols TDM

A

TDM

A tim




e) in each round


5 D

ata

Lin

k La

yer

5-9


exam

ple 6-station LAN


34

13

4

6-slotfram

e


C protocols FDM

A

FDM


ultiple access



unused transm


exam

ple 6-station LAN

13


5 D

ata

Lin

k La

yer

5-1

0

exam

ple 6-station LAN


frequency bands

FDM

cable

Random A

ccess Protocols

W




ong nodes

two or more transm


rdquo

random access M


5 D

ata

Lin

k La

yer

5-11

random

access MA

C protocolspecifies



retransmissions)

Exam


AC protocols

_____________________

_____________________

CSMA


ccess)

CSMA



e


Da

taL

ink L

aye

r5

-12

hum


CSMA



eans two nodes m


ission

collision

5 D

ata

Lin

k La

yer

5-1

3


time wasted



CSMA

CD (Collision D

etection)CSM

ACD


collisions detected

within short time

colliding transm


collision detection

5 D

ata

Lin

k La

yer

5-1

4

collision detection

easy in wired LAN


compare transm





hum



AC protocols


C protocols


at high load



5 D

ata

Lin

k La

yer

5-1

5

node Random

access MA

C protocols





Summ

ary of MA

C protocols


e frequency or code

Time D


random

access (dynamic)

A

LOH

A S-A

LOH

A CSM

A CSM

ACD



5 D

ata

Lin

k La

yer

5-1

6



CSM

ACD

used in Ethernet

CSMA

CA used in 80211

taking turns


Bluetooth FD

DI IBM

Token Ring

Ethernetldquodom

inantrdquowired LA

N technology

cheap $20 for N

IC


technology


Ns and A

TM


10 Gbps

5 D

ata

Lin

k La

yer

5-1

7

pp

pp

p

Metcalfe


Star topology


all nodes in sam


other)



each ldquospoke



5 Da

taLink Layer

5-18

switch



connectionlessN


ICs



IC

stream of datagram


5 D

ata

Lin

k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic


MA


Three broad classes

_______________


(time slots

frequency code)


5 D

ata

Lin

k La

yer

5-8

________________



collisions

_________________


longer turns


C protocols TDM

A

TDM

A tim




e) in each round


5 D

ata

Lin

k La

yer

5-9


exam

ple 6-station LAN


34

13

4

6-slotfram

e


C protocols FDM

A

FDM


ultiple access



unused transm


exam

ple 6-station LAN

13


5 D

ata

Lin

k La

yer

5-1

0

exam

ple 6-station LAN


frequency bands

FDM

cable

Random A

ccess Protocols

W




ong nodes

two or more transm


rdquo

random access M


5 D

ata

Lin

k La

yer

5-11

random

access MA

C protocolspecifies



retransmissions)

Exam


AC protocols

_____________________

_____________________

CSMA


ccess)

CSMA



e


Da

taL

ink L

aye

r5

-12

hum


CSMA



eans two nodes m


ission

collision

5 D

ata

Lin

k La

yer

5-1

3


time wasted



CSMA

CD (Collision D

etection)CSM

ACD


collisions detected

within short time

colliding transm


collision detection

5 D

ata

Lin

k La

yer

5-1

4

collision detection

easy in wired LAN


compare transm





hum



AC protocols


C protocols


at high load



5 D

ata

Lin

k La

yer

5-1

5

node Random

access MA

C protocols





Summ

ary of MA

C protocols


e frequency or code

Time D


random

access (dynamic)

A

LOH

A S-A

LOH

A CSM

A CSM

ACD



5 D

ata

Lin

k La

yer

5-1

6



CSM

ACD

used in Ethernet

CSMA

CA used in 80211

taking turns


Bluetooth FD

DI IBM

Token Ring

Ethernetldquodom

inantrdquowired LA

N technology

cheap $20 for N

IC


technology


Ns and A

TM


10 Gbps

5 D

ata

Lin

k La

yer

5-1

7

pp

pp

p

Metcalfe


Star topology


all nodes in sam


other)



each ldquospoke



5 Da

taLink Layer

5-18

switch



connectionlessN


ICs



IC

stream of datagram


5 D

ata

Lin

k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic



C protocols TDM

A

TDM

A tim




e) in each round


5 D

ata

Lin

k La

yer

5-9


exam

ple 6-station LAN


34

13

4

6-slotfram

e


C protocols FDM

A

FDM


ultiple access



unused transm


exam

ple 6-station LAN

13


5 D

ata

Lin

k La

yer

5-1

0

exam

ple 6-station LAN


frequency bands

FDM

cable

Random A

ccess Protocols

W




ong nodes

two or more transm


rdquo

random access M


5 D

ata

Lin

k La

yer

5-11

random

access MA

C protocolspecifies



retransmissions)

Exam


AC protocols

_____________________

_____________________

CSMA


ccess)

CSMA



e


Da

taL

ink L

aye

r5

-12

hum


CSMA



eans two nodes m


ission

collision

5 D

ata

Lin

k La

yer

5-1

3


time wasted



CSMA

CD (Collision D

etection)CSM

ACD


collisions detected

within short time

colliding transm


collision detection

5 D

ata

Lin

k La

yer

5-1

4

collision detection

easy in wired LAN


compare transm





hum



AC protocols


C protocols


at high load



5 D

ata

Lin

k La

yer

5-1

5

node Random

access MA

C protocols





Summ

ary of MA

C protocols


e frequency or code

Time D


random

access (dynamic)

A

LOH

A S-A

LOH

A CSM

A CSM

ACD



5 D

ata

Lin

k La

yer

5-1

6



CSM

ACD

used in Ethernet

CSMA

CA used in 80211

taking turns


Bluetooth FD

DI IBM

Token Ring

Ethernetldquodom

inantrdquowired LA

N technology

cheap $20 for N

IC


technology


Ns and A

TM


10 Gbps

5 D

ata

Lin

k La

yer

5-1

7

pp

pp

p

Metcalfe


Star topology


all nodes in sam


other)



each ldquospoke



5 Da

taLink Layer

5-18

switch



connectionlessN


ICs



IC

stream of datagram


5 D

ata

Lin

k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic



C protocols FDM

A

FDM


ultiple access



unused transm


exam

ple 6-station LAN

13


5 D

ata

Lin

k La

yer

5-1

0

exam

ple 6-station LAN


frequency bands

FDM

cable

Random A

ccess Protocols

W




ong nodes

two or more transm


rdquo

random access M


5 D

ata

Lin

k La

yer

5-11

random

access MA

C protocolspecifies



retransmissions)

Exam


AC protocols

_____________________

_____________________

CSMA


ccess)

CSMA



e


Da

taL

ink L

aye

r5

-12

hum


CSMA



eans two nodes m


ission

collision

5 D

ata

Lin

k La

yer

5-1

3


time wasted



CSMA

CD (Collision D

etection)CSM

ACD


collisions detected

within short time

colliding transm


collision detection

5 D

ata

Lin

k La

yer

5-1

4

collision detection

easy in wired LAN


compare transm





hum



AC protocols


C protocols


at high load



5 D

ata

Lin

k La

yer

5-1

5

node Random

access MA

C protocols





Summ

ary of MA

C protocols


e frequency or code

Time D


random

access (dynamic)

A

LOH

A S-A

LOH

A CSM

A CSM

ACD



5 D

ata

Lin

k La

yer

5-1

6



CSM

ACD

used in Ethernet

CSMA

CA used in 80211

taking turns


Bluetooth FD

DI IBM

Token Ring

Ethernetldquodom

inantrdquowired LA

N technology

cheap $20 for N

IC


technology


Ns and A

TM


10 Gbps

5 D

ata

Lin

k La

yer

5-1

7

pp

pp

p

Metcalfe


Star topology


all nodes in sam


other)



each ldquospoke



5 Da

taLink Layer

5-18

switch



connectionlessN


ICs



IC

stream of datagram


5 D

ata

Lin

k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic


Random A

ccess Protocols

W




ong nodes

two or more transm


rdquo

random access M


5 D

ata

Lin

k La

yer

5-11

random

access MA

C protocolspecifies



retransmissions)

Exam


AC protocols

_____________________

_____________________

CSMA


ccess)

CSMA



e


Da

taL

ink L

aye

r5

-12

hum


CSMA



eans two nodes m


ission

collision

5 D

ata

Lin

k La

yer

5-1

3


time wasted



CSMA

CD (Collision D

etection)CSM

ACD


collisions detected

within short time

colliding transm


collision detection

5 D

ata

Lin

k La

yer

5-1

4

collision detection

easy in wired LAN


compare transm





hum



AC protocols


C protocols


at high load



5 D

ata

Lin

k La

yer

5-1

5

node Random

access MA

C protocols





Summ

ary of MA

C protocols


e frequency or code

Time D


random

access (dynamic)

A

LOH

A S-A

LOH

A CSM

A CSM

ACD



5 D

ata

Lin

k La

yer

5-1

6



CSM

ACD

used in Ethernet

CSMA

CA used in 80211

taking turns


Bluetooth FD

DI IBM

Token Ring

Ethernetldquodom

inantrdquowired LA

N technology

cheap $20 for N

IC


technology


Ns and A

TM


10 Gbps

5 D

ata

Lin

k La

yer

5-1

7

pp

pp

p

Metcalfe


Star topology


all nodes in sam


other)



each ldquospoke



5 Da

taLink Layer

5-18

switch



connectionlessN


ICs



IC

stream of datagram


5 D

ata

Lin

k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic


CSMA


ccess)

CSMA



e


Da

taL

ink L

aye

r5

-12

hum


CSMA



eans two nodes m


ission

collision

5 D

ata

Lin

k La

yer

5-1

3


time wasted



CSMA

CD (Collision D

etection)CSM

ACD


collisions detected

within short time

colliding transm


collision detection

5 D

ata

Lin

k La

yer

5-1

4

collision detection

easy in wired LAN


compare transm





hum



AC protocols


C protocols


at high load



5 D

ata

Lin

k La

yer

5-1

5

node Random

access MA

C protocols





Summ

ary of MA

C protocols


e frequency or code

Time D


random

access (dynamic)

A

LOH

A S-A

LOH

A CSM

A CSM

ACD



5 D

ata

Lin

k La

yer

5-1

6



CSM

ACD

used in Ethernet

CSMA

CA used in 80211

taking turns


Bluetooth FD

DI IBM

Token Ring

Ethernetldquodom

inantrdquowired LA

N technology

cheap $20 for N

IC


technology


Ns and A

TM


10 Gbps

5 D

ata

Lin

k La

yer

5-1

7

pp

pp

p

Metcalfe


Star topology


all nodes in sam


other)



each ldquospoke



5 Da

taLink Layer

5-18

switch



connectionlessN


ICs



IC

stream of datagram


5 D

ata

Lin

k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic


CSMA



eans two nodes m


ission

collision

5 D

ata

Lin

k La

yer

5-1

3


time wasted



CSMA

CD (Collision D

etection)CSM

ACD


collisions detected

within short time

colliding transm


collision detection

5 D

ata

Lin

k La

yer

5-1

4

collision detection

easy in wired LAN


compare transm





hum



AC protocols


C protocols


at high load



5 D

ata

Lin

k La

yer

5-1

5

node Random

access MA

C protocols





Summ

ary of MA

C protocols


e frequency or code

Time D


random

access (dynamic)

A

LOH

A S-A

LOH

A CSM

A CSM

ACD



5 D

ata

Lin

k La

yer

5-1

6



CSM

ACD

used in Ethernet

CSMA

CA used in 80211

taking turns


Bluetooth FD

DI IBM

Token Ring

Ethernetldquodom

inantrdquowired LA

N technology

cheap $20 for N

IC


technology


Ns and A

TM


10 Gbps

5 D

ata

Lin

k La

yer

5-1

7

pp

pp

p

Metcalfe


Star topology


all nodes in sam


other)



each ldquospoke



5 Da

taLink Layer

5-18

switch



connectionlessN


ICs



IC

stream of datagram


5 D

ata

Lin

k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic


CSMA

CD (Collision D

etection)CSM

ACD


collisions detected

within short time

colliding transm


collision detection

5 D

ata

Lin

k La

yer

5-1

4

collision detection

easy in wired LAN


compare transm





hum



AC protocols


C protocols


at high load



5 D

ata

Lin

k La

yer

5-1

5

node Random

access MA

C protocols





Summ

ary of MA

C protocols


e frequency or code

Time D


random

access (dynamic)

A

LOH

A S-A

LOH

A CSM

A CSM

ACD



5 D

ata

Lin

k La

yer

5-1

6



CSM

ACD

used in Ethernet

CSMA

CA used in 80211

taking turns


Bluetooth FD

DI IBM

Token Ring

Ethernetldquodom

inantrdquowired LA

N technology

cheap $20 for N

IC


technology


Ns and A

TM


10 Gbps

5 D

ata

Lin

k La

yer

5-1

7

pp

pp

p

Metcalfe


Star topology


all nodes in sam


other)



each ldquospoke



5 Da

taLink Layer

5-18

switch



connectionlessN


ICs



IC

stream of datagram


5 D

ata

Lin

k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic



AC protocols


C protocols


at high load



5 D

ata

Lin

k La

yer

5-1

5

node Random

access MA

C protocols





Summ

ary of MA

C protocols


e frequency or code

Time D


random

access (dynamic)

A

LOH

A S-A

LOH

A CSM

A CSM

ACD



5 D

ata

Lin

k La

yer

5-1

6



CSM

ACD

used in Ethernet

CSMA

CA used in 80211

taking turns


Bluetooth FD

DI IBM

Token Ring

Ethernetldquodom

inantrdquowired LA

N technology

cheap $20 for N

IC


technology


Ns and A

TM


10 Gbps

5 D

ata

Lin

k La

yer

5-1

7

pp

pp

p

Metcalfe


Star topology


all nodes in sam


other)



each ldquospoke



5 Da

taLink Layer

5-18

switch



connectionlessN


ICs



IC

stream of datagram


5 D

ata

Lin

k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic


Summ

ary of MA

C protocols


e frequency or code

Time D


random

access (dynamic)

A

LOH

A S-A

LOH

A CSM

A CSM

ACD



5 D

ata

Lin

k La

yer

5-1

6



CSM

ACD

used in Ethernet

CSMA

CA used in 80211

taking turns


Bluetooth FD

DI IBM

Token Ring

Ethernetldquodom

inantrdquowired LA

N technology

cheap $20 for N

IC


technology


Ns and A

TM


10 Gbps

5 D

ata

Lin

k La

yer

5-1

7

pp

pp

p

Metcalfe


Star topology


all nodes in sam


other)



each ldquospoke



5 Da

taLink Layer

5-18

switch



connectionlessN


ICs



IC

stream of datagram


5 D

ata

Lin

k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


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Ethernetldquodom

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N technology

cheap $20 for N

IC


technology


Ns and A

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10 Gbps

5 D

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Metcalfe


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ata

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k La

yer

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Ethernetrsquos MA


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Ethernet CSMA

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ata

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from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

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about 50 msec

Exponential Backoff


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5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

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obile

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6 W

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Mo

bile

Ne

two

rks6

-22

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base station



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Mo

bile

Ne

two

rks6

-23




network

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m

ultiple access

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Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

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TS

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DM

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SP

DA

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MA

20001

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(Mbps)

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two

rks6

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Indoor10-30m

Outdoor

50-200mM

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Long-rangeoutdoor

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056

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IS-95 C

DM

A G

SM

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TS

WC

DM

A C

DM

A2000

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80215

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2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

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Mo

bile

Ne

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rks6

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infrastructurep

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no base stations



nodes organize

6 Wire

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etw

orks6-27

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6 W

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noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

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atter (path loss)


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-29

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hellip make com







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6 W

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AB

____________problem

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space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

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Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

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80211b 24GH

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P

6 W

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Mo

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two

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host must associate

with an AP


avoid collisions 2


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rc

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CA

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space


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for DIFS

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hil

hl idl

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DIFS

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er expiresif no A



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)

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base station mobile

dynamically change

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lti

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BER 10

-1

10-2

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-3

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-4

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bile

Ne

two

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M256 (8 M

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obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


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eter


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ireless a

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bile

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-39

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MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

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delay im


e traffic


Star topology


all nodes in sam


other)



each ldquospoke



5 Da

taLink Layer

5-18

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connectionlessN


ICs



IC

stream of datagram


5 D

ata

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k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

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5 D

ata

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its3 If N

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012hellip2m-1N



Ethernetrsquos CSMA

CD (m

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about 50 msec

Exponential Backoff


attempts to estim

ated current load


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5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


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base station



6 W

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Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

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A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

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6 W

ireless a

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Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic



connectionlessN


ICs



IC

stream of datagram


5 D

ata

Lin

k La

yer

5-1

9

stream


(missing datagram

s)



Ethernetrsquos MA


CD

Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic


Ethernet CSMA

CD algorithm


from


e2 If N


e transmission



transmission while


sends jam signal

5 After aborting N


5 D

ata

Lin

k La

yer

5-2

0



its3 If N

IC transmits entire




e


th collision N


from

012hellip2m-1N



Ethernetrsquos CSMA

CD (m

ore)Jam

Signalmake sure all



e1 microsec for 10

Mbps Ethernet


about 50 msec

Exponential Backoff


attempts to estim

ated current load


will be longer

5 D

ata

Lin

k La

yer

5-2

1

about 50 msec



ission times


0123hellip


01234hellip1023


network

wireless hosts

laptop PDA IP phone

run applications

may be stationary

(non-mobile) or m

obile

wireless does not

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-22

infrastructure


ean mobility


network

base station



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-23




network

wireless link




m

ultiple access

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-24

infrastructure

multiple access



ission distance


4

5-11

54

80211b

80211ag

UM

TS

WC

DM

AH

SP

DA

CD

MA

20001

EV

DO

3Gcellular

80216 (WiM

AX

)

80211ag p

oin

t-to-p

oin

t

20080211n

(Mbps)

data

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-25

Indoor10-30m

Outdoor

50-200mM

id-rangeoutdoor

200m ndash

4 Km

Long-rangeoutdoor

5Km

ndash20 K

m

056

384 1 4

IS-95 C

DM

A G

SM

2G

UM

TS

WC

DM

A C

DM

A2000

3G

80215

UM

TS

WC

DM

A-H

SP

DA

CD

MA

2000-1xEV

DO

3G cellular

enhanced

Data rate (


network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

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architecture

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80211 LAN

architecture

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handoff m


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larger Internet


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MAN

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80211 LAN

architecture

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wireless hosts


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ode hosts onlyBSS 1

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80211b 24GH

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P

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handoff m


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bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


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single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

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-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

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6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







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ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

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ACK


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BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

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nd

Mo

bile

Ne

two

rks6

-38


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obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



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ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic



network

__________ mode



handoff m


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-26

infrastructurep

ginto wired network


______ mode

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nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic



______ mode

no base stations



nodes organize

6 Wire

less and Mobile N

etw

orks6-27

nodes organize them


ong them

selves


y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic



y

single hopm

ultiple hops



iFiW

iMAX cellular)


host may have to


Internet mesh net

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-28

noinfrastructure

larger Internet


ad hoc nets)

Internet mesh net




MAN

ET VANET


Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

)

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


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es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic



Differences from

wired link hellip


atter (path loss)


z) shared by h

d (

h

) d (

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6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-29

qg




es

hellip make com







B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



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data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



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ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic





B

CA

BC

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-30

AB

____________problem

B A hear each other

B C hear each other



space

80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


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es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


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Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic


80211 LAN

architecture

wireless host com

municates

with base station

_______________


ode contains

Internet

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-31

mode contains

wireless hosts


ad hoc m

ode hosts onlyBSS 1

BSS 2

hub switchor router

AP

AP


80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic



80211b 24GH

z-2485GHz spectrum


AP adm




P

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-32

yg

g

host must associate

with an AP


avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic



avoid collisions 2


e time

80211 CSM

A -







6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-33

to wa

rc

sgna

s (fang)


inal fading



AB

CA

BC


space


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic


IEEE 80211 MA

C Protocol CSMA

CA


for DIFS

thentransm


)2 if


backoff time

i

d

hil

hl idl

senderreceiver

DIFS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-34


transmit when tim

er expiresif no A



if frame received O

Kreturn A



)

data

SIFS

ACK


ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic



ore)idea



es



A


BS b

dsts

lt

sd CTS i

sp

s t

RTS

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-35




e



pletely using sm



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic



APA

B

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-36

time


base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic



base station mobile

dynamically change

transmission rate

(physical layer d

lti

th

i)

BER 10

-1

10-2

10

-3

10-5

10

-6

10

-4

6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-37


as mobile m

oves SNR

varies

QA

M256 (8 M

bps)Q

AM

16 (4 Mbps)

BP

SK

(1 Mbps)

10

20

30

40

SN

R(dB

)

10

-7

operating point

1 SNR decreases BER



2 When BER becom




anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic



anagement



erdquo


es to this noded

k

b

f

b f6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-38


e


obiles with AP-to-m



obile frames


e

Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic


Mradius ofcoverage

SP

P


less than 10 m diam

eter


(mouse keyboard

headphones)


6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-39

SS

PP

MS

Master device

Slave device


P

m

asterslaves


send (to master)

m


80215 evolved from



up to 721 kbps

Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic


Wireless m


logically im

pact shouldbe m

inimal hellip



TCP and U


obile



6 W

ireless a

nd

Mo

bile

Ne

two

rks6

-40




delay im


e traffic


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