Wireless TechnologiesSOFYAN BASUKI

Sofmae4@gmail.com

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OutlineWireless technology overviewCellular communicationsSatellite systemsWireless LAN

◦ 802.11, Bluetooth, UWBMobility support

◦ WAPWireless applications

Why Wireless?Human freedom

◦ Portability v. MobilityObjective: “anything, anytime, anywhere”Mobility

◦ Size, weight, power◦ Functionality◦ Content

Infrastructure requiredCost

◦ Capital, operational

Worldwide Mobile Subscribers

0200,000400,000600,000800,000

1,000,0001,200,0001,400,0001,600,0001,800,000

2000 2001 2002 2003 2004 2005

ROWJapanAsia PacificLatin AmericaWestern EuropeNorth America

SOURCE: CTIA, iGillottResearch, 2001

Electromagnetic Spectrum

SOURCE: JSC.MIL

SOUND LIGHTRADIO HARMFUL RADIATION

VHF = VERY HIGH FREQUENCYUHF = ULTRA HIGH FREQUENCYSHF = SUPER HIGH FREQUENCY EHF = EXTRA HIGH FREQUENCY

4G CELLULAR56-100 GHz

3G CELLULAR1.5-5.2 GHz

1G, 2G CELLULAR0.4-1.5GHz

UWB3.1-10.6 GHz

MOBILE

FIXED

MARITIME MOBILE

BROADCAST

AERO

RADIOLOCATION

Wireless Telephony

SOURCE: IEC.ORG

AIR LINK

PUBLIC SWITCHEDTELEPHONE NETWORK

WIRED

Cell Clusters

SOURCE: IEC.ORG

ACTUAL COVERAGEAREA OF CELL 1

ACTUAL COVERAGEAREA OF CELL 3

CELL 1 OVERLAPS 6 OTHERS

DIFFERENT FREQUENCIESMUST BE USED IN ADJACENTCELLS

SEVEN DIFFERENT SETS OFFREQUENCIES REQUIRED

Space Division Multiple Access (SDMA)

PATTERN CAN BEREPLICATED OVERTHE ENTIRE EARTH

200 FREQUENCIESIN ONE CELL

TOTAL NUM BER OFFREQUENCIES = 1400

WORLDWIDE

MANY CELLS CAN SHARESAME FREQUENCIES IFSEPARATED IN SPACE

Cell Handover

SOURCE: R. C. LEVINE, SMU

AS PHONE MOVES FROM CELL “A” TO CELL “B”: • CELL “A” MUST HAND THE CALL OVER TO “B” • PHONE MUST CHANGE FREQUENCIES • CELL “A” MUST STOP TRANSMITTING

Minimum performancecontour

Handover thresholdcontour

A Bx y

z

ANIMATION

Cell SizesMACROCELL: $1M

MICROCELL: $250K

SLOW-MOVINGSUBSCRIBERS

FAST-MOVINGSUBSCRIBERS

PICOCELLS

GSM: 100m - 50 km 250 km/hr

Multiple Access

Many users sharing a resource at the “same time”

Needed because user must share cellsFDMA (frequency division)

◦ Use different frequenciesTDMA (time division)

◦ Use same frequency, different timesCDMA (code division)

◦ Use same frequency, same time, different “codes”

Frequency Division Multiplexing (FDMA)

Advantages: No dynamic

coordination

Disadvantages: Inflexible & inefficient if

channel load is dynamic and uneven

k2 k3 k4 k5 k6k1

f

t

c

Each channel gets a band (range) of frequenciesUsed in traditional radio, TV, 1G cellular

SOURCE: NORMAN SADEH

k2 k3 k4 k5 k6k1

Time Division Multiplexing (TDMA)

Each channel gets entire spectrum for a certain (rotating) time period

Advantage: Can assign more time to senders with heavier loads 3X capacity of FDMA, 1/3 of power consumptionDisadvantage: Requires precise synchronization

SOURCE: NORMAN SADEH

f

t

c FREQUENCY BAND

EACH CHANNELOCCUPIES SAME

FREQUENCY

Combining TDMA and FDMA

f

t

c

k2 k3 k4 k5 k6k1

Each channel gets a certain frequency band for a certain amount of time. Example: GSM

Advantages:• More robust against frequency-

selective interference• Much greater capacity with

time compression• Inherent tapping protection

Disadvantages• Frequency

changes must be coordinated

SOURCE: NORMAN SADEH

Time-Division Multiple Access

SOURCE: QUALCOMM

Code Division Multiplexing (CDMA) Each channel has unique

“code” All channels use same spectrum

at same time but orthogonal codes Advantages:

◦ bandwidth efficient – code space is huge◦ no coordination or synchronization

between different channels◦ resists interference and tapping◦ 3X capacity of TDMA, 1/25 power consumption

Disadvantages:◦ more complex signal regeneration

Implemented using spread spectrum

k2 k3 k4 k5 k6k1

f

t

c

Cellular Generations First

◦ Analog, circuit-switched (AMPS) Second

◦ Digital, circuit-switched (GSM, Palm) 10 Kbps Advanced second

◦ Digital, circuit switched, Internet-enabled (WAP) 10 Kbps

2.5◦ Digital, packet-switched, TDMA (GPRS, EDGE)

40-400 Kbps Third

◦ Digital, packet-switched, wideband CDMA (UMTS)0.4 – 2 Mbps

Fourth◦ Data rate 100 Mbps; achieves “telepresence”

GSM Architecture

SOURCE: UWC

LIST OFROAMINGVISITORS

LIST OF SUBSCRIBERSIN THIS AREA

STOLEN, BROKENCELLPHONE LIST

ENCRYPTION,AUTHENTICATION

INTERFACE TO LANDTELEPHONE NETWORKS

HIERARCHYOF CELLS

CELL TRANSMITTER& RECEIVER

PHONE

SIM:IDENTIFIES ASUBSCRIBER

DATA RATE: 9.6 Kbps

SMS – Short Message Service Integral part of GSM standard

◦ Added to other standards as well Uses control channel of phone

◦ Send/Receive short text messages◦ Sender pays (if from mobile phone)

Phone has "email" address◦ SMTP Interface Only in the US, not the rest of the world Allows messages to be sent for free!

◦ 3125551234@wireless.att.net1 BILLION SMS/day worldwide

Technology Message Length

2 way?

GSM 160 bytes YesTDMA/PDC 160 bytes NoCDMA 256 bytes YesiDEN 140 bytes Yes

SOURCE: GEMBROOK SYSTEMS

SMS in Banking

Credit card used

Joe’s HiFi$1245

BankBack-endSystems

Internet

Bank Web Site

Message from YourBank: Credit card

purchase of $1245 at Joe’s HiFi.

Message appears within seconds

on the customer’s phone

SMS Monitorin

g Application

Customer

Alert me to all credit

card transactions greater than

$100.

Cell Tower

Air

WirelessCarrier

SMS Carrier

SOURCE: GEMBROOK SYSTEMS

Satellite Systems

SOURCE: WASHINGTON UNIV.

GEO

M EO

LEO

GEO (22,300 mi., equatorial) high bandwidth, power, latencyMEO high bandwidth, power, latencyLEO (400 mi.) low power, latency more satellites small footprintV-SAT (Very Small Aperture) private WANSATELLITE MAP

Geostationary Orbit

SOURCE: BILL LUTHER, FCC

GPS Satellite Constellation• Global Positioning

System• Operated by USAF• 28 satellites• 6 orbital planes at a

height of 20,200 km• Positioned so a

minimum of 5 satellites are visible at all times

• Receiver measures distance to satelliteSOURCE: NAVSTAR

GPS Trilateration

DISTANCE MEASUREMENTSMUST BE VERY PRECISE

LIGHT TRAVELS 1018 FEETEACH MICROSECOND

SOURCE: PETER DANA

Automatic Vehicle Location (AVL)SOURCE: TRIMBLE NAVIGATION

Benefits of AVL• Fast dispatch• Customer service• Safety, security• Digital messaging• Dynamic route optimization• Driver compliance

Sample AVL Users• Chicago 911• Inkombank, Moscow• Taxi companies

Intelligent Highway demoCA

Location-Aware Applications

Vehicle trackingFiremen in buildings, vital signs, oxygen

remainingAsset trackingBaggageShoppers assistanceRobotsCorporate visitorsInsuranceBarges

Wireless LAN

Idea: just a LAN, but without wiresNot as easy since signals are of limited range

◦ Unlike wired LAN, if A can hear B and B can hear C, not necessarily true that A can hear C

Uses unlicensed frequencies, low power802.11 from 2 Mb to 54 MbBluetoothUWB

Wireless LAN Components

SOURCE: LUCENT

WavePOINT IITransmitter

ExtendedRange

Antenna

EthernetConverter

11 Mbps WaveLANPCMCIA Card

WaveLAN ISA(Industry StandardArchitecture) Card

Wireless LAN Configurations

SOURCE: PROXIM.COM

WIRELESS PEER-TO-PEERCLIENT AND ACCESS POINT

MULTIPLE ACCESS POINTS + ROAMING

BRIDGING WITHDIRECTIONAL ANTENNAS

UP TO 17 KM !

Bluetooth A standard permitting for wireless connection of:

Personal computersPrintersMobile phonesHandsfree headsetsLCD projectorsModemsWireless LAN devicesNotebooksDesktop PCsPDAs

Bluetooth Characteristics Operates in the 2.4 GHz Industrial-Scientific-Medical (ISM) (unlicensed)! band. Packet switched. 1 milliwatt (as opposed to 500 mW cellphone. Low cost.

10m to 100m range Uses Frequency Hop (FH) spread spectrum, which divides the frequency band into a number of hop channels. During connection, devices hop from one channel to another 1600 times per second

Bandwidth 1-2 megabits/second Supports up to 8 devices in a piconet (two or more Bluetooth units sharing a channel).

Built-in security. Non line-of-sight transmission through walls and briefcases. Easy integration of TCP/IP for networking.

Bluetooth Devices

NOKIA 9110 + FUJIDIGITAL CAMERA

ERICSSONCOMMUNICATOR

ERICSSON R520GSM 900/1800/1900

ALCATELOne TouchTM 700

GPRS, WAPERICSSON

BLUETOOTHCELLPHONE

HEADSET

Bluetooth Piconets

• Piconet = small area network• “Ad hoc” network: no predefined structure• Based on available nodes and their locations• Formed (and changed) in real time

Bluetooth Scatternets

Master

Slave

Piconet

ScatterNet

Master / Slave

Scatternet Piconets

SOURCE: KRISHNA BHOUTIKA

Time-Modulated Ultra-Wideband (TM-UWB) Not a sinewave,

but millions of pulses per second

Time coded to make noise-likesignal

Pulse position modulation

500 ps

Time

Randomized Time Coding

Am

plitu

de

d d

d = 125 ps

“0” “1” Pow

er S

pect

ral D

ensi

ty (d

B)

-80

-40

0

Frequency (GHz)1 2 3 4 5

Frequency (GHz)

Random noise signal

SOURCE: TIME DOMAIN

Spread Spectrum

Ultra Wideband PropertiesVERY low power: 0.01 milliwatt

◦Bluetooth 1 milliwatt (100 x UWB)◦Cellphone 500 milliwatts (50,000 x UWB)

Range: 30 to 300 feetVery small Low cost100 Mbits/secondUp to 500 Mbps for short distances

(USB speed)No interferenceSecure

PulsON, A Chip Based Solution

Wireless Application Support

WAP (Wireless Application Protocol) and iMode

High-level protocols that use cellular transport

WAP:◦ Uses WML (Wireless Markup Language)◦ Divides content into “cards” equal to one telephone

screen◦ Simplified but incompatible form of HTML◦ To send to a WAP phone, must broadcast WML

content

WAP ApplicationsWeb Content

Server

MobileTerminal

MobileNetwork

Internet

WAP Gateway

Non Mobile Internet User

DatabaseServer

SOURCE: DANETWAP simulator

iNexware

iModeTelephone, pager, email, browser, location

tracking, banking, airline tickets, entertainment tickets, games

NTT DoCoMo ( ドコモ means “anywhere”) Japan is the wireless Internet leader:

SOURCE: EUROTECHNOLOGY JAPAN K.K.iMode FAQ

iMode

Sits on top of packet voice/data transportAs of July 31, 2003, > 39 million subscribers

◦ 28,000 new ones per day26% of Japan>3000 “official” sites>1000 application partners>40,000 unofficial sitesFee based on amount

of data transmitted

SOURCES: XML.COM, EUROTECHNOLOGY.COM

iMode

Phonetic text input (better for Japanese)SLOW: 9.6 Kbps, but 3G will raise to 384 KUses cHTML (compact HTML)

◦ same rendering model as HTML (whole page at a time)

◦ low memory footprint (no tables or frames)Standby time: 400 min., device weight 2.4 oz.

(74g)

SOURCES: XML.COM, NTT

iMode Operation

IP

DoCoMoPacket

Network (PDC-P)IP

INFOPROVIDER

INTERNET

iMode Servers

BILLINGDB

USERDB

PACKET DATAHTTP

SOURCE: SAITO & SHIN

Wireless Standards802.11b (2.4 GHz 300’ radius 11 Mbps)

802.11a (5 GHz 54 Mbps incompatible with b)802.11g (2.4 GHz 54 Mbps backward compatible with b)802.20 (<3.5 GHz >1 Mbps @250 kph) BlueTooth (2.4 Ghz 30’ radius)GSM (9.6 Kbps) GPRS (28.8 Kbps up to 60 Kbps )3G (UMTS 1.1 Mbit/s shared typically giving 80 Kbit/s )4G 2010? (10 Mbs? )UWB potential to deliver 500 Mbps over short distances

SOURCE: JOHN DOWNARD

Key Takeaways

Mobile growing very rapidlyCell systems need large infrastructureWireless LAN does notContent preparation is a problemWireless business models largely unexploredBandwidth, bandwidth, bandwidth

QA&

Code Division

SOURCE: JOCHEN SCHILLER

1 10DATA

1 1 1 1 1 1 1 10 0 0 0 0 00000“CODE”

0 0 0 0 0 0 0 0 0 011 1 1 1111DATA CODE

+1

-1

ACTUALSIGNAL

Code Division

SOURCE: JOCHEN SCHILLER

1 00DATA B

0 1 1 0 0 1 1 10 1 0 0 0 10100“CODE” B

1 0 0 1 0 0 0 1 1 111 0 0 1011DATA CODE

+1

-1

ACTUALSIGNAL

B

Two CDMA Signals

SOURCE: JOCHEN SCHILLER

+1

-1

ACTUALSIGNAL

A

+1

-1

ACTUALSIGNAL

B

ACTUALSIGNAL

A+B

+2

-2

Recovering Data A From A+B

SOURCE: JOCHEN SCHILLER

+2

-2

ACTUALSIGNAL

A+B

1 1 1 1 1 1 1 10 0 0 0 0 00000“CODE” A

+2

-2

-(A+B) *CODE A

+1

-1

INTEGRAL1

0

1