IIT Colloquium: NRC

Ottawa, Canada

A Vision for Evolving Local Wideband Wireless Networks

Kaveh Pahlavan, Professor of Electrical and Computer Engineering and

Director, CWINS/WLRL

WPI, Worcester, MA

http://www.cwins.wpi.edu

CWINS

OutlineOutline

• Applications and the market

• Existing technologies and limitations

• Evolving standards

• Overview of Global activities

• Some research projects

Classification of Existing Wireless NetworksClassification of Existing Wireless Networks

Voice Driven Networks

• Low power, high quality, local services (PCS, wireless PBX, telepoint)-Result of success in cordless telephone industry

• High power, low quality, wide area (Digital Cellular) -Result of demand for higher capacity for mobile radio

Data Driven Networks

• High speed local (Wireless LAN) - A new approach for local area networking

• Low speed wide area (mobile data) - Result of success in paging industry

Current Wireless Network IndustryCurrent Wireless Network Industry

CWINS@wpi

Voice ServicesTariff

Mobility

Service AreaSize/Power

Quality

IntelligentNetwork

CellularPCS

CWINS@wpi

Data ServicesNo. Users

Mobility

Service AreaSize/Power

Data Rate

Interoperability

MobileData

WLANS

Wireless LANsWireless LANs

• Minimum data rate: 1Mbps (IEEE 802)

• Designed for local indoor - less than 100m

• Should interoperate with wired LANs

• Does not need large investment on infrastructure and does not collect service charges.

• Transmission technology: spread spectrum, standard radio, IR

• Examples: Roamabout, WAVELan, Photolink, FreePort

• Standards: IEEE 802.11, HIPERLAN

History of Wireless LANsHistory of Wireless LANs

• Diffused Infrared - 1979 (IBM Rueschlikon Labs - Switzerland)

• Spread Spectrum using SAW Devices - 1980 (HP Labs - California)

• Wireless modems - early 1980's (Data Radio)

• ISM bands for commercial spread spectrum applications - 1985

• IEEE 802.11 for Wireless LAN standards - 1990

• Announcement of wireless LAN products - 1990

• Formation of WINForum - 1992

• ETSI and HIPERLAN in Europe - 1992

• Release of 2.4, 5.2 and 17.1-17.3GHz bands in EC - 1993

• PCS licensed and unlicensed bands for PCS - 1993

• 1996: .........

Three Views of WWLAThree Views of WWLA

• Existing WLAN Applications

• Vision for Military Applications

• Vision of the Service Providers

Service ScenariosService Scenarios

• Workplace - the main market of today, TCP/IP applications, legacy LAN backbone

• Home - universal access point: Internet connection, cordless telephone, flexible speakers, etc. backbone unknown (ATM preferred).

• Nomadic public access - backbone unknown, easier traffic policing and charging with WATM.

Wireless LAN TechnologiesWireless LAN TechnologiesTechnique DF/IR DB/IR RF DS/SS FH/SS

Data Rate 1 - 4 Mbps 10 - 155 Mbps 5 - 10 Mbps 2 - 20 Mbps 1 - 3 Mbps

Mobility Stationary/Mobile Stationary w/LOS Stationary/Mobile Stationary/Mobile Mobile

Range 50 - 200 ft 100 ft 40 - 130 ft 100 - 800 ft 100 - 300 ft

Freq./wavelength 800 - 900 nm 800 - 900 nm 18 GHz, ISM ISM bands ISM bands

Modulation OOK OOK FSK/QPSK QPSK GFSK

Access Method CSMA CSMA Res. ALOHA, CSMA CSMA CSMA

Manufacturer Spectrix InfraLAN (token ring) Motorola - Altair DEC ProximJOLT (pt-to-pt) AiroNet RDC

WaveLAN (mesh) XircomPersoftSolectekProximWindataWiLAN

Wireless LAN MarketWireless LAN Market

0

200

400

600

800

1000

1200

1992 1993 1994 1995 1996

K-Unit

Local Wideband Wireless ActivitiesLocal Wideband Wireless Activities

• Evolving Standard Technologies– IEEE 802.11

– RES-10 HIPERLAN

– Wireless ATM Forum

• International Activities– In the US

• WINForum, U-NII

– In the EC• MEDIAN, WAND, SAMBA and AWACS

– In Japan• MMAC (High-Speed WirelessAccess and Ultra High-Speed Radio

LAN)

802.11 PHY

802.11 MAC 802.3 MAC

802.3 PHY802.11 PHY

802.11 MAC

IP

TCP

Applications Applications

TCP

IP

802.3 MAC

802.3 PHY

802.11 PHY

802.11

MAC

802.11 PHY

802.11 MAC

IP

TCP

ApplicationsApplications

TCP

IP

(a)

(b)

LANE

AAL5

ATM

PHY

AAL

Custom PHY

WATM

Custom PHY

WATM

IP

TCP

Applications Applications

TCP

IP

(c)

ATM

PHY

AALAAL

Mobile Terminal

Server

Fixed Terminal

Backbone Network

Access Point

ATM

PHY

ATM

PHY

Interconnection between WLAN/WATM to backboneInterconnection between WLAN/WATM to backbone

ESS

Existing Wired LAN

APAP

BSS 3BSS 2

Infrastructure Network

BSS 1

BSS 2Ad Hoc Networks

BSS 1

AP

802.11 Configurations802.11 Configurations

IEEE 802.11 and ISM bandsIEEE 802.11 and ISM bands

• Media Access Protocol (MAC) for both peer-to-peer and centralized topologies

• Uses 2.4 MHz ISM bands

• Supports DSSS (BPSK and QPSK), FHSS (GFSK), and DFIR (OOK)

• Data rates are 1 and 2 Mbps for DSSS and FHSS, 1Mbpsfor DFIR

• For DSSS the band is divided in two groups:

Group I centralized at: 2412, 2442, and 2472 MHz

Group II centralized at: 2427, and 2457 MHz

• For FHSS three patterns of 22 hops out of 79 available I MHz bands with GFSK. Minimum hop rate is 2,5 hops/second

• Provide interoperatability among all stations

IAPP (Supported byLucent, Aironet, Digital Ocean)

IAPP (Supported byLucent, Aironet, Digital Ocean)

• The IAPP specification defines how access points from different vendors communicate with each other to support mobile stations roaming across cells and how they communicate across the backbone network to hand over mobile stations.

• The IAPP specification builds on the baseline capabilities of the IEEE 802.11 standard.

• The IAPP specification tackles higher-level OSI layers such as logical link control that facilitates inter-access point communications.

• The IAPP specification supports interoperability between products.

• Should be applicable to large infra-structures

F

F

F

RIBNIBHIBAIBSMRIBTIB

RIBNIBHIBAIBSMRIBTIB RIB

NIBHIBAIBSMRIBTIB

RIBNIBHIBAIB

RIBNIBHIBAIB

RIBNIBHIBAIB

1 2

3

4

5

6

HIB {HDest , HStatus , HNext }

RIB {RDest , RNext , RDist }

NIB {NNbour , NStatus }

AIB {AOri , AAlias }

SMRIB {SSMR , SSeq }

TIB {TDest , TLast , TSeq }

is S

MR

of

is SM

R of

is SM

R of

HIPERLAN 1

HIPERLAN 2Neighborhood

Hiperlan ad-hoc network configurationHiperlan ad-hoc network configuration

ETSI Res-10: HIPERLANETSI Res-10: HIPERLAN

• MAC for both peer-to-peer and centralized networks

• Uses 5.25-5.3 GHz and 17.1-17.3 GHz• Uses GMSK modulation with DFE• Data rates are 10-20 Mbps• The maximum range is 50m• Supports asynchronous data as well as

isochronous voice

Wireless ATM Architecture [WATM Working Group Presentation]

Wireless ATM Architecture [WATM Working Group Presentation]

Frequency Band Modulation Technique

Data Rate Access Method Topologies MAC Services QoS Availibility

WIRELESS

802.11

Spread Spectrum Direct Sequence: 2.4-2.4835 GHz, Frequency Hopping: 2.4-2.4835 GHz; Diffused Infrared: 850-950 nanometer

Spread Spectrum Direct Sequence: DBPSK, DQPSK; Spread Spectrum Frequency Hopping: 2GFSK, 4GFSK BT=0.5; Diffused Infrared: 16 and 4 PPM

1 and 2 Mbps

Basic CSMA/CA, RTS/CTS, PCF with polling list, 20 frames

Ad-hoc, Infra-structure

Authentication, Encryption, Power conservation, Time bounded services

No explicit support for QoS, but includes infrastructure topology and priority scheme in PCF that are useful for quality assurance.

Technial standard finalized. Final administrative approval under progress. Products (e.g DEC Roamabout) and chipsets (e.g. Harris PRISM and Raytheon RAYLINK) are available.

LAN

HIPERLAN

5.15-5.30 GHz Low bit rate: FSK; High bit rate:GMSK (BT=0.3)

1.47 and 23.53 Mbps

Non-Preemptive Multiple Access (NPMA), 10 PDU

Ad-hoc Encryption, Power conservation, Routing and forwarding, Time bounded services

Advanced user priority scheme and packet lifetime mechanism to support QoS

Standard is finalized. No product in the market. Two prototypes: HIPERION, fully standards compliant, and LAURA, not fully compliant [Wil96].

WIRELESS

MII Bahama

900 MHZ (Proposed 5 GHz U-NII Bands)

OFDM or GMSK with LMS or RLS Equalization

2-20 Mbps between laptop and PBS, and Gbps between PBSs

Distributed Queue Reservation Updated Multiple Access (DQRUMA): Reservation and Piggybacking

Infrastructure, ad hoc base station placement (optional)

Scheduling, piggybacking etc.

Base station responsible for checking and guaranteeing QoS, connections with or without QoS guarantees possible.

Prototype at Bell labs in Lucent Technologies

NEC

2.4 GHz ISM Bands

/4 - QPSK with decision feedback equalization

8 Mbps TDMA/TDD with Slotted ALOHA

Infrastructure based

Scheduling, multiplexing and demultiplexing of VCs

ABR, UBR, VBR and CBR slots are available but QoS support is not finalized

Prototype at NEC USA's C&C Research Laboratories, Princeton, NJ.

ATM

Magic WAND

5.2 GHz 16 Channel OFDM > 24 Mbps Reservation, Slotted ALOHA: Mobile Access Scheme based on Contention and Reservation (MASCARA)

Infrastructure Based

Scheduling, radio resource management and under further study

Worst case QoS estimate (cell delay or cell loss) to be used for determining the connection

Prototyping under the European ACTS AC085 project

Comparison of WLAN and WATMComparison of WLAN and WATM

Wireless ATM ActivitiesWireless ATM ActivitiesWATM System SWAN1 MII/BAHAMA1 Olivetti NEC WAND

Frequency Bands 2.4 GHz ISM Bands 900 MHz (Proposed5 GHz : U-NII)

2.4 GHz ISM Bands 2.4 GHz ISM Bands 5.2 GHz

Data Rate 625 kbps 2-20 Mbps 10 Mbps 8 Mbps 24 MbpsModulation Scheme Frequency Hopping (suggested OFDM

or GMSK withLMS/RLS)

QPSK /4 - QPSK withDFE

16 channel OFDM

Medium Access Each mobile has afixed channel; tokenpassing

Distributed queuereservation updatedmultiple access(DQRUMA)

Reservation withSlotted Aloha andpiggy-backing ondata cells

TDMA/TDD withSlotted Aloha

Reservation withSlotted Aloha

PacketFormat/Addressing

Various types oflink cells

Custom wirelessand LANE

see [POR94] see [RAY97] LANE

Handoffs/roaming Mobile initiated Mobile initiated Mobile initiated(with Mobile Manager)

Infrastructureinitiated (with MobileRepresentative)

Mobile initiated Mobile initiated

Techniques forreliability

FEC with (8,4)linear codes

FEC (proposedReed-SolomonCodes for real-timetraffic andFEC/retransmissiosfor data

16 bit CRC andARQ

Data Link Controlfor error recovery

FEC

QoS MAC supports QoS Supported Priority for certaintraffic

Fixed slots availablefor QoS support

Worst case QoSestimate to be used

References [AGR96] [ENG95],[AYA96] [POR96],[POR94] [RAY97] [WAND96]

Table 3.3.1: Wireless ATM Activities

1 Lucent Bell Labs

European Wideband Wireless ActivitiesEuropean Wideband Wireless ActivitiesTable 4.3.1: European Wireless Wideband Activities

Project Full Name andNumber

Objective Details

MEDIAN AC006Wireless Broadband

CPN/LAN forProfessional and

ResidentialMultimedia Services

Evaluate andimplement a highspeed WLAN formultimediaapplications anddemonstrate it inreal user trials

Multicarrier modulation(512 channels + OFDM)

60 GHz band One base station at 155

Mbps, two portables, one at34 Mbps and one at 155Mbps

WAND AC085Wireless ATM

NetworkDemonstrator

Develop andevaluate a realisticWATMtransmissionfacility at 5 GHz

Data rates from 20 Mbps to155 Mbps

See previous section

SAMBA AC204System for

Advanced MobileBroadband

Applications

Demonstratemobile userapplications at upto 34 Mbps andprove the MBSconcept

Trial platform of 2 base and2 mobile stations operatingat 40 GHz

Design state of the artASICs

Implement mobilitymanagement and handoverfunctions

AWACS Advanced WirelessATM

CommunicationsSystems

Development ofsystem conceptand testbeddemonstration oftetherless publicaccess to B-ISDNservices

Low mobility terminalsoperating at 19 GHz

Data rates of up to 34 Mbps Transmission range of

100m Contribution to standards

development

Japanese Wideband Wireless ActivitiesJapanese Wideband Wireless ActivitiesTable 4.4.1: Proposed MMAC systems and their parameters

MMAC System High-Speed Wireless Access Ultra High-Speed Radio LANService Area Indoors and outdoor IndoorConnected Networks Public networks or private

networksPrivate networks only (ATM)

Transmission Speed Average 6-10 MbpsMaximum 25 Mbps

155 Mbps

Terminal Equipment Notebooks and PCs Desktop PCs and workstationsMobility Stationary or pedestrian

(handovers allowed)Stationary onlyRelocation handover permitted

Frequency Bands 25 or 40 or 60 GHz 60 GHzBandwidth 500-1000 MHz 1-2 GHzQuality bit error rate of 10-6 bit error rate of 10-8

MMAC: Multemedia Mobile Access Communications

Unlicensed PCS Activity (Spectrum Etiquette)

Unlicensed PCS Activity (Spectrum Etiquette)

Three basic Principles:• Listen before talk (or transmit) LBT Protocol• Low transmitter power• Restricted duration of transmissions

Unlicensed National Information Infrastructure Devices

Unlicensed National Information Infrastructure Devices

Table 4.2.1. FCC Requirements for the U-NII Frequency Bands

Band ofoperation

MaximumTx Power

Max. Powerwith antennagain of 6 dBi

Maximum PSD Applications:suggested and/or

mandated

Other Remarks

5.15 - 5.25 GHz 50 mW 200 mW 2.5 mW/MHz Restricted toindoorapplications

Antenna must bean integral partof the device

5.25 - 5.35 GHz 250 mW 1000 mW 12.5 mW/MHz Campus LANs Compatible withHIPERLAN

5.725-5.825 GHz 1000 mW 4000 mW 50 mW/MHz Communitynetworks

Longer range inlow-interference(rural) environs.

Issues in a Mobile NetworkIssues in a Mobile Network

• Type of roaming

– Intra-Net (802.11)

– Inter-Net (GPRS)

– Inter-Tech (between GPRS and 802.11)

• Type of mobility

– Continual during a move

– Access at different locations

• Type of connection

– With a unique address (mobile IP)

– With any address (cash IP)

• Type of initiation for roaming

– From the terminal

– From th network

Evolving Roaming Related TechnologiesEvolving Roaming Related Technologies

• Intra-Net Roaming– LANE in WATM

– 802.11

– Hiperlan

• Inter-Tech Roaming– MASE

– Artour

• Inter-Net Roaming– Mobile-IP

Layers for ImplementationLayers for Implementation

Physical

MAC

Network IP

Transportation TCP

Session

Presentation

Application

802.

11, H

IPERLAN,L

ANE

ARTour

Win

sock

MASE{

Mobile

IP

Mobile IPMobile IP

Mobile HostMobile Host

Mobile HostMobile Host

MM

MM

SS

R1R1 R2R2 R3R3 R4R4

R20R20

RouterRouter Home AgentHome Agent

Foreign AgentForeign Agent

SenderSender

inform if possibleinform if possible

LC

Local cache

“IP in IP” Encapsulation“IP in IP” Encapsulation

TCP and rest of packetTCP and rest of packet

IP Version number, and other header fields

IP Version number, and other header fieldsIP Version number, and other header fields

Tunnel Source IP address (home agent)

CARE-OF Address (foreign agent)

Original source IP addressOriginal source IP address

Home IP address of mobile hostHome IP address of mobile host

Why Client-Server is Important Why Client-Server is Important

• Most of the current legacy applications are client-server

• Facilitates implementation of mobility• Facilitates interoperability• Facilitates scaleability• Can support multiple platforms• Local optimization of the server to enhance

reliability and availability and results in reducing costs

Important Client-Server ApplicationsImportant Client-Server Applications

• Web search, • FTP, • Data base access, • Telnet, • Email

ReferencesReferences

• K. Pahlavan , A. Zahedi, and P. Krishnamurty, “ Wideband Local Access: Wireless LAN and Wireless ATM”, invited paper, Speical Issue on WATM, IEEE Comm. Soc. Mag., Nov. 1997.

• K. Pahlavan and A. Levesque, Wireless Information Networks, New York: John Wiley and Sons, 1995.

• K. Pahlavan, A. Falsafi, G. Yang, “Transmission Techniques for Wireless LANs”, IEEE JSAC, Speical Issue on Wireless Local Communications, May 1996.

• K. Pahlavan and A. Levesque, “Wireless Data Communication”, Invited Paper, IEEE Proceedings, Sep. 1994.

• K. Pahlavan, “Wireless Intra-Office Networks”, Invited paper, ACM Trans. on Office Inf. Sys., July 1988. (also published as the opening paper in “Advances in Local and Metropolitan Area Networks”, edited by William Stalling, IEEE Press, 1994)

• K. Pahlavan, “Wireless Office Information Networks”, IEEE Comm. Soc. Mag, Sep. 1985.

• K. Pahlavan, T. H. Probert, and M. E. Chase, “Trends in Local Wireless Networks”, Invited Paper, IEEE Comm. Soc. Mag., March 1995.