WLAN™IEEE 802.11

WPAN™IEEE 802.15

WMAN™IEEE 802.16

802.15.1“Bluetooth”

802.15.3“High Data Rate” MAC & 2.4 GHz PHY

Task Group 3aAlt PHY (UWB)

802.15.4“Zigbee” 2.4 GHz

LAN/MAN Standards Committee (Wireless Areas)

802.15.2Coexistence

IEEE 802 Organization

MBWAIEEE 802.20

Study Group 4a(UWB?)

What is Bluetooth?• Open Standard for Short Range Wireless Connectivity • Designed for Transmitting Data and Audio Wirelessly• Uses Radio Frequency (RF) Technology in the Unlicensed 2.4Ghz ISM

Frequency Band.• Initial Target Applications include PC & PDA Peripherals, Wireless Audio

& Data, Data Synchronization, In-Vehicle (Telematics) • Future Applications include Wireless Access Points, Healthcare,

Industrial Applications, Cordless Telephony, Smart Appliances, Entertainment – Wireless Gaming.

• Provides for Ad Hoc device Connection and Service Discovery • Promises Lower Power Consumption and Lower Cost per Node Than

Competing Wireless Technologies

• More Robust than Infrared (IrDA).

– RF based, not limited to line-of-sight.– Supports 10 meter range (class 2), versus 1 meter.

• Power Consumption

– Bluetooth provides several classes of operation that provide significant power advantages over other wireless alternatives such as 802.11

• Projected to be Less Costly Than 802.11 & HomeRF.

– 802.11 & HRF estimate is > $25 per node, Bluetooth target is < $ 5 when embedded in volume.

– Bluetooth costs will start declining sharply 1st half 2003.

Why Bluetooth?

• Range

– 802.11 WLAN & Home RF provide greater connection distance

• Data Rate

– Bluetooth today provides 1Mbps raw data rate, lower than competing technologies, 802.11b (11Mbps), 802.11a (54Mbps)

• Hyped expectations have damaged its credibility• Available 2 years latter than expected• Interoperability problems with early products• Interference from other products in the ISM band• Future Technologies Promise Lower Power, Lower Latency

– wireless USB

Why Not Bluetooth?

Summary

• Bluetooth got off to a slow start but Momentum is Building • Key Revenue Generators Today are Audio related (Headsets &

In-Vehicle Applications) and Data Related• Currently 819 Qualified Products listed on the SIG web site,

more added daily• For Further BT V1.1 Specification and Profile details, go to

www.bluetooth.com

Ultra Wide Band

Range and Data Rate

Introduction

• What is UWB?– A series of very short baseband pulses with time

duration in nano-seconds that exist on ALL frequencies simultaneously, like a blast of electrical Noise.

• Synonyms:– Non-sinusoidal Communication Technology– Impulse Radio– Baseband Pulse Technology

• UWB is a form of extremely wide spread spectrum where RF energy is spread over gigahertz of spectrum– Wider than any narrowband system by orders of magnitude– Power seen by a narrowband system is a fraction of the total– UWB signals can be designed to look like imperceptible random

noise to conventional radios

Large Relative (and Absolute) Bandwidth

Frequency

Narrowband (30kHz)

Wideband CDMA (5 MHz)

UWB (Several GHz)

Part 15 Limit( -41.3dBm/Hz )

– Capacity: a channel is linearly proportional to its bandwidth. UWB can go up to 2 Giga-Hz in bandwidth.• Spread spectrum: transmission in which the data sequence

occupies a bandwidth in excess of the minimum bandwidth necessary to send it. It uses only several frequencies, one at a time.

• Successor to spread spectrum: UWB uses every frequency there is, use them all at same time.

– Simplicity: it’s essentially a base-band system (Carrier free), for which the analog front-end complexity is far less than that for a traditional sinusoidal radio. (See Figures at next page.)

Why is UWB attractive?

• 7.5 Ghz of “free spectrum” in the U.S.– FCC recently legalized UWB for commercial use– Spectrum allocation overlays existing users, but its allowed

power level is very low to minimize interference

• Very high data rates possible– 500 Mbps can be achieved at distances of 10 feet under

current regulations

• “Moore’s Law Radio”–Data rate scales with the shorter pulse widths made possible

with ever faster CMOS circuits

• Simple CMOS transmitters at very low power– Suitable for battery-operated devices– Low power is CMOS friendly

Why is UWB attractive?

Pros• High data capacity.

– Multiple Access provided by time hopping scheme. Can support close to 30,000 users at 19.2kbps with BER of 10-3 or a 6 users system with a peak speed of 50mbps.

• Low power.– Transmitting at microwatts (one tenth thousandth power of cell phone) results in very low

harmful interference to other radio systems. Usually below the noise floor and undetectable.

– Longer battery life for mobile devices. • Resilient to distortions and fading (Great for indoor usage).

– Spread spectrum property overcomes frequency selective fading.– High information redundancy and frequency diversity provides protection

against multi-path distortion. • Simplicity translate to lower hardware cost.

– No carrier frequency translate analog front-end has simpler implementation than traditional sinusoidal radio.

• Security– UWB is inherently secure: Only a receiver that knows the schedule of the

transmitter can assemble the apparently random pulses into a coherent message.

Cons• Interference with GPS.

– Global positioning satellite currently have more than 10 million users and it’s primarily applications are used for the safety of public. (I.e. aircraft flight and approach guidance.) UWB presents a problem to GPS because their frequency overlaps, and GPS signal is particular sensitive to interference (It as SNR level around –164 dBW.)

• Limited on range– Output power is limited in order to keep down the noise floor due to its

overlapping frequency bandwidth with other radio systems.• One kilometer with high gain antenna.• Ten to twenty meter with regular antenna.

• Affects on economy and current businesses.– Speculations on UWB making current billion dollar FCC licensed frequencies

worthless.– Increased competition for local cable or phone company. Making their existent

investments on cable and equipments obsolete.• Side Note.

– FCC adopted a First Report and Order that permits the marketing and operation of certain types of new products incorporating UWB technology, Feb 14,2002.

– Biggest loser: Increase the noise floor level for radio astronomer.

• UWB as WPAN (IEEE 802.15.3a) currently, debating with PHY layer and MAC layer - optimal MAC vs. 802.15.3 MAC vs. 802.11a MAC - QOS scheduling algorithm for multimedia stream - Interoperability with 802.11, Bluetooth, wired LAN, sensor network(?) - security policy• UWB as Localization device (in sensor network or other mobile node) - optimal localization protocol in ad hoc network (task dispatching between UWB and RF unit) - security issue• UWB as alternate RF component (in sensor network or other mobile

node) - optimal MAC - routing algorithm - QOS scheduling

Possible Research Topics for UWB

Wireless USB Vision

Physical Design

• Features of wUWB– Speed/Range• Scaleable speeds up over 1 Gbps• Currently 480 Mbps at 3 m; 110 Mbps at 10 m

– Frequency: 3.1 GHz to 10.6 GHz• Divided into 14 bands; 5 groups

– Each band is 528 MHz wide– OFDM symbols are interleaved across all bands– Provides protection against multi-path / interference

Physical Design

• Features of wUWB (cont.)– Frequency: 3.1 GHz to 10.6 GHz (cont.)

• Band Groups 1 & 2: Longer range apps• Bands Groups 3 & 4: Shorter range apps• Bands can be turned off to accommodate for conflicts or for

regulations

Physical Design

Features of wUWB (cont.)- Power• Power is limited due

to usage of wide spectrum• Low power for mobile

devices and minimuminterference

• Max output to-41.3 dBm/MHz

Wireless USB Connection Design

• Host/Slave Connection– Similar to wired USB (127 devices; host is PC)– Each host forms a cluster– Clusters can coexist with minimum interference

• Power Management– Sleep/Listen/Wake

used to conservepower

– Tx/Rx powermanagement

Issues/Problems

• Interference Issues– Potential conflict to devices on same frequencies– “Detect and Avoid”

• Wisair’s solution to detect other frequencies• Switches to frequencies not being used

– Conflict issues are more of a concern for wireless USB devices being overpowered

• Competing Standards– Cable-Free USB (Freescale)– USB-Implementers Forum (Intel, HP, Microsoft)

Concluding Thoughts

• Appears well designed; good support• Slow start of products

– Will it really catch on?– More products need to be developed

• Promises a lot; will it deliver?• Security is very important

Zig Bee

ZigBee802.15.4

Wi-Fi802.11b

Wi-Fi5802.11a/HL2

GSM/CDMA GPRS/3G LMDS

High Data RateLow Data Rate

Sh

ort

Ran

geL

ong

Ran

ge

WAN

LAN

PAN

Bluetooth 2

Text

Digitalvideo Multi-channel

video

GraphicsInternet

Hi-Fiaudio Streaming

video

Bluetooth 1802.15.1

WiMedia802.15.3

Market Application Landscape

Why ZigBee?

• Standard in a fragmented market– Many proprietary solutions, interoperability issues

• Low Power consumption– Users expect battery to last months to years!

• Low Cost• High density of nodes per network• Simple protocol, global implementation

ZigBee vs Bluetooth

Competition or Complementary?

Bluetooth is Best

For :

• Ad-hoc networks between capable devices

• Handsfree audio• Screen graphics, pictures…• File transfer

But ZigBee is Better

IF :

• The Network is static• Lots of devices• Infrequently used• Small Data Packets

Bluetooth:• New slave enumeration = >3s• Sleeping slave changing to active = 3s typically• Active slave channel access time = 2ms typically

ZigBee:• New slave enumeration = 30ms typically • Sleeping slave changing to active = 15ms typically• Active slave channel access time = 15ms typically

Timing Considerations

ZigBee protocol is optimized for timing critical applications