November 5, 2004 ©KP University of Massachusetts

November 5, 2004 ©KP

University of MassachusettsUniversity of Massachusetts

CWINS

Evolution of Wireless Network

K. Pahlavan

2

Outline Introduction Voice-Oriented Cellular Networks

– 1G analog cellular– 2G

• Cellular, PCS, Mobile data, WLAN

– 3G and beyond• IMT-2000• Broadband and adhoc networks• Future directions and 4G systems

Wireless Data Networks– Mobile data– Broadband Adhoc networks

3

Traditional fixed network infrastructure

Additional fixed infrastructure to support mobility

Wireless access

What is a wireless network?

4

Computer

Workstation

Laptop

Printer

Telephone

Fax

Keyboard

Mouse

Scanner

PDA

Mainframe

CRT projector

Video

Pen computer

Hand held computer

Cell phone

iBook

Evolution of terminals

Morse Pad

5

Bandwidth Requirements for Applications

1

100,000

10

100

1,000

10,000

MP

EG

2 V

ideo

3D G

ames

Ba

nd

wid

th (

Kb

ps

)

(100 Mbps)

(10 Mbps)

(1 Mbps)

Pri

nti

ng

Inte

rnet

Sec

uri

ty S

yste

ms

Gam

es

Ph

on

e A

pp

lian

ces

Rea

l A

ud

io G

2

MP

3 A

ud

io

Sm

art

Ap

pli

ance

s

Uti

lity

Met

erin

g

Cam

cord

er D

V

6

Tariff

Intelligent Network

Service quality

Power consumption

Coverage

cellular

cordless

Mobile data

Wireless LANs

Users per network

Compatibility with LANs

Data rate

Size/power consumption

Mobility

Coverage

Four Original Traditional Industries

7

1G Systems

Analog cellular or mobile phone for the car Analog cordless telephones for homes Pagers (?) as mobile data Low-speed LANs using voiceband modems

and walkie-talkies as local wireless (?)

8

Standard

Forward Band MHz

Reverse Band MHz

Channel Spacing

kHz

Region Comments

AMPS 824-849 869-894 30 America Also in Australia, SE Asia, Africa

TACS 890-915 935-960 25 EC Later, bands were allocated to GSM

ETACS 872-905 917-950 25 UK NMT 450 453-457.5 463-467.5 25 EC NMT 900 890-915 935-960 12.5 EC Freq.

overlapping Also in Africa and SE Asia

C-450 450-455.74 460-465.74 10 Germany Portugal

RTMS 450-455 460-465 25 Italy Radiocom 2000

192.5-199.5 215.5-233.5 165.2-168.4 414.8-418

200.5-207.5 207.5-215.5 169.8-173 424.8-428

12.5 France

NTT 925-940 915-918.5 922-925

870-885 860-863.5 867-870

25/6.25 6.25 6.25

Japan First band is nationwide, others regional

JTACS/NTACS

915-925 898-901 918.5-922

860-870 843-846 863.5-867

25/12.5 25/12.5 12.5

Japan All are regional

1G Analog Cellular Systems

9

2G Systems

Digital cellular for mobile users PCS for pedestrians Independent Mobile data for portable

computers WLANs for wire replacement

10

System GSM IS-54 JDC IS-95 Region Europe/Asia USA Japan USA/Asia Access Method TDMA/FDD TDMA/FDD TDMA/FDD CDMA Modulation Scheme GMSK /4-DQPSK /4-DQPSK QPSK Frequency Band (MHz)

935-960 890-915

869-894 824-849

810-826 940-956

1477-1489 1429-1441 1501-1513 1453-1465

869-894 824-849

Carrier Spacing (kHz) 200 30 25 1250 Bearer channels/carrier

8 3 3 Variable

Channel bit rate (kbps)

270.833 48.6 42 1228.8

Speech Coding 13 kbps 8 kbps 1-8 kbps (variable)

Average handset Tx. Power (mW)

125 mW 20 mW 20 mW

Peak power (W) 1 0.6 Frame duration (ms) 4.615 40 20 20

2G Digital Cellular Systems

11

System CT2 and

CT2+ DECT PHS PACS

Region Europe Canada Europe Japan United States

Access Method TDMA/TDD TDMA/TDD TDMA/TDD TDMA/FDD

Frequency band (MHz) 864-868 944-948 1880-1900 1895-1918

1850-1910 1930-1990

Carrier spacing (KHz) 100 1728 300 300, 300 Number of carriers 40 10 77 16 pairs Bearer channels/carrier 1 12 4 8 per pair Channel bit rate (kb/s) 72 1152 384 384 Modulation GFSK GFSK /4-DQPSK /4-DQPSK Speech coding 32 kb/s 32kb/s 32 kb/s 32 kb/s Ave. handset Tx power (mW) 5 10 10 25 Peak handset Tx power (mW) 10 250 80 200 Frame duration (ms) 2 10 5 2.5

2G Digital Cordless (PCS)

12

System ARDIS Mobitex CDPD TETRA GPRS Metricom Frequency band (MHz)

800 bands 45 kHz sep

935-940 896-961

869-894 824-849

380-383 390-393

890-915 935-960

902-928 ISM bands

Channel bit rate (kbps)

19.2 8.0 19.2 36 300-400 100

RF channel spacing

25KHz 12.5KHz 30KHz 25KHz 200 KHz 160KHz

Channel Access/ Multi-user access

FDMA/ DSMA

FDMA/ Dynamic S-ALOHA

FDMA/ DSMA

FDMA/ DSMA

FDMA/ TDMA/ Reserve

FHSS/ BTMA

Modulation Technique

4-FSK GMSK GMSK /4-DQPSK

GMSK GMSK

Mobile Data Systems (2G, 2.5G?)

HDR that can support up to over 2Mbps

13

WLAN Standards (2G,3G,4G?)

Parameters IEEE 802.11 IEEE 802.11b

IEEE 802.11a HIPERLAN/2 HIPERLAN/1

Status Approved, Products

Final ballot, Products

Final ballot, Products

In preparation Approved, No products

Freq. Band 2.4 GHz 2.4 GHz 5 GHz 5 GHz PHY, modulation

DSSS: FHSS:

DSSS: CCK

OFDM GMSK

Data rate 1, 2 Mbps 1, 2, 5.5, 11 Mbps

6, 9, 12, 18, 24, 36, 54 Mbps 23.5 Mbps

Access method

Distributed control, CSMA/CA Or RTS/CTS

Central control. Reservation based access

Active contention resolution, Priority signalling

Also 802.11g that is OFDM in 2.4GHz coexisting with 11.b.

14

3G W-CDMA for IMT-2000

CDMA provides a better quality of voice CDMA is more flexible air interface to

customize multi-media applications Two overall approaches

– build on the success of the installed GSM infrastructure (UMTS/IMT-2000)

– build on the cdmaOne experience (cdma2000/IMT-2000)

15

Mbps1 10 1000,1

Out

door

Fixed

Walk

Vehicle

Indo

or

Fixed/Desktop

Walk

Mobility

3G Cellular

W-LAN

User Bitrate, Datacom services

WPAN

2G C

ellu

lar

Wide Area Network (WAN)- Expensive licensed bands

Local Area Network (LAN)- High speed unlicensed

Personal Area Network (PAN)-Ad-hoc unlicensed

Overview of the Current Wireless Access Methods

16

Two Sectors of Wireless Industry:

Voice-Oriented Cellular– 3G IMT-2000 for Access– Integrates Cellular, PCS, and Mobile Data– Operates in licensed bands

Data-Oriented Broadband Ad-hoc– WLAN and WPAN – Provides for broadband wireless Internet access

and wireless media for consumer products – in unlicensed bands for traditional

17

Beyond 3G

First Generation: Analog Cellular, Analog Cordless, Pager (?), Local Area Low-Speed Packet Data

Second Generation: Digital Cellular, PCS, Mobile Data, Wireless LAN

Third Generation: Improved Quality and Capacity for the Voice and Higher Data Rates for the Data.

Beyond 3G: – Integration with WLAN in unlicensed bands– Increase the quality and capacity using time-space diversity – Include location aware services– Include ad-hoc networking capabilities

18

Braodband and Ad-Hoc Access:

Wireless LAN for broadband access– IEEE 802.11 – HIPERLAN

Wireless PAN for ad-hoc networking – Bluetooth– UWB

19

PCMCIA cards and Laptops

Shoebox type LAN Extension

Wired Backbone

Building Cross-connect

(1)

(2)

(3)

Evolution of WLAN Products:

20

W-CAN

ATWATER KENT LABORATORIES

Salisbury Laboratories

Gordon Library

Fuller

Olin Hall

Wireless Access Point

Electronic whiteboard

WirelessBridge

WirelessBridge

WirelessBridge

WirelessBridge

WirelessBridge

WirelessBridge

WirelessBridge

WirelessBridge

Laboratories

Switch

Router

Campus Backbone Network

21

OfficeEthernet

Corporate Network

Internet

Home

Home Environment

ISP

3rd generation Cellular

Public Networks

Telecomm. View

22

BW-Internet Access

23

Personal Ad-hoc Personal Ad-hoc NetworksNetworks

Cable Cable ReplacementReplacement

Landline

Data/Voice Data/Voice Access Access PointsPoints

WPAN Vision for Bluetooth

24

Broadband Home-Distribution

Broadband Home-Access

Two Technologies for Home

Internet

25

Military interest ………..

26

Body LAN or Wearable LAN

27

Urban fighting ………..

28

Self healing mines ….

29

Unmanned combat air vehicle…

30

Fixed-mobile networks

31

Wireless vs Wired Wireless operates on the unreliable radio channel that needs far

more complex PHY layer as well as connection management Wireless should arrange change of connection point during the

moves by a more complex registration and call routing Wireless has limited number of channels (radio frequency bands)

that should be managed to be shared among a huge number of users

Wireless needs security (authenticate and ciphering) to avoid fraud and preserve privacy

Wireless, due to bandwidth scarcity, needs more complex source coding techniques (e.g. for voice or video)

Wireless needs permanent and temporary addressing to support mobility

Wireless mobile operates out of the battery energy and needs power management

Wireless terminals use small screens that needs special graphics

32

Elements of a Wireless Network Architecture

Services– voice, data, call forwarding, …

System infrastructure to connect the mobile user to the existing fixed networks– Mobile terminal– Fixed wireless infrastructure

Detailed layered protocols to tie all components together – PHY, Data Link, Network Layer

Traffic engineering and deployment

33

Technical Aspects of Wireless Infrastructure

Network deployment planning Mobility and location management Radio resource and power management Security

34

Technical Aspects for Air-Interface

Understanding of the medium (path-loss, variations of the channel and multipath effects)

Study of the PHY layer alternatives (pulse transmission techniques, traditional RF, spread spectrum)

Study of the MAC layer alternatives (voice-oriented FDMA, TDMA and CDMA, and data-oriented: ALOHA and CSMA based)

35

What is important in wireless?

In voice oriented networks– 2G designed a new digital air-interface to facilitate data applications

and increase the capacity of analog 1G– 3G designed a CDMA air-interface to provide higher data rates and

improve the quality and capacity– 4G possibly uses time-space diversity and MIMO air-interface to

get what 3G did not In data oriented networks

– 802.11 used spread spectrum modem because FCC wanted it.– CCK modems were developed for 802.11b to increase the data rate

at 2.4GHz– OFDM was used in 802.11a and g to further increase the data rate– UWB is expected to increase the data rate and number of users

36

What is a telecomm network ?

Satellite

Satellite dish

Satellite dish

Point-to-point plus interconnect elements (switches/routers)

37

Traditional fixed telephone infrastructure

Additional fixed components for a wireless infrastructure

Wireless Voice-Oriented Networks

38

System Aspects PCS Cellular Cell size 5-500 m 0.5-30 Km Coverage Zonal Comprehensive Antenna height < 15 m > 15 m Vehicle speed < 5 kph < 200 kmp Handset comp. Low Moderate Base station comp. Low High Spectrum access Shared Exclusive Average handset power 5-10 mW 100-600 mW Speech coding 32 kb/s ADPCM 7-13 kb/s vocoder Multipath mitigation Antenna diversity

(optional) Diversity/equalizati

on/Rake Duplexing Usually TDD FDD Detection Non-coherent Coherent

Comparison of PCS and Cellular