Wireless Technologies

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Wireless Technologies

Modified by Amang Sudarsono
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Outline

• Wireless technology overview
• Cellular communications
• Satellite systems
• Wireless LAN
• 802.11, Bluetooth, UWB
• Mobility support
• WAP
• Wireless applications

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Why Wireless?

• Human freedom
• Portability v. Mobility
• Objective anything, anytime, anywhere
• Mobility
• Size, weight, power
• Functionality
• Content
• Infrastructure required
• Cost
• Capital, operational

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Worldwide Mobile Subscribers
SOURCE CTIA, iGillottResearch, 2001
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Electromagnetic Spectrum
LIGHT
HARMFUL RADIATION
RADIO
SOUND
VHF VERY HIGH FREQUENCY UHF ULTRA HIGH
FREQUENCY SHF SUPER HIGH FREQUENCY EHF EXTRA
HIGH FREQUENCY
UWB 3.1-10.6 GHz
SOURCE JSC.MIL
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MARITIME MOBILE
FIXED
BROADCAST
MOBILE
AERO
RADIOLOCATION
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Wireless Telephony
WIRELESS
AIR LINK
WIRED
PUBLIC SWITCHED TELEPHONE NETWORK
SOURCE IEC.ORG
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Cell Clusters
CELL 1 OVERLAPS 6 OTHERS DIFFERENT
FREQUENCIES MUST BE USED IN ADJACENT CELLS SEVEN
DIFFERENT SETS OF FREQUENCIES REQUIRED
SOURCE IEC.ORG
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Space Division Multiple Access (SDMA)
MANY CELLS CAN SHARE SAME FREQUENCIES
IF SEPARATED IN SPACE
PATTERN CAN BE REPLICATED OVER THE ENTIRE EARTH
200 FREQUENCIES IN ONE CELL TOTAL NUM BER
OFFREQUENCIES 1400 WORLDWIDE
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Cell Handover
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 performance contour
A
B
x
y
z
Handover threshold contour
ANIMATION
SOURCE R. C. LEVINE, SMU
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Cell Sizes
GSM 100m - 50 km 250 km/hr
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Multiple Access

• Many users sharing a resource at the same time
• Needed because user must share cells
• FDMA (frequency division)
• Use different frequencies
• TDMA (time division)
• Use same frequency, different times
• CDMA (code division)
• Use same frequency, same time, different codes

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Frequency Division Multiplexing (FDMA)
Each channel gets a band (range) of
frequencies Used in traditional radio, TV, 1G
cellular

• Advantages
• No dynamic coordination
• Disadvantages
• Inflexible inefficient if channel load is
  dynamic and uneven

EACH CHANNEL OCCUPIES SAME FREQUENCY AT ALL TIMES
SOURCE NORMAN SADEH
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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 consumption Disadvantage Requires precise
synchronization
SOURCE NORMAN SADEH
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Combining TDMA and FDMA
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
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Time-Division Multiple Access
SOURCE QUALCOMM
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Code Division Multiplexing (CDMA)

• Each channel has uniquecode
• All channels use same spectrumat same time but
  orthogonal codes
• Advantages
• bandwidth efficient code space is huge
• no coordination or synchronizationbetween
  different channels
• resists interference and tapping
• 3X capacity of TDMA, 1/25 power consumption
• Disadvantages
• more complex signal regeneration
• Implemented using spread spectrum

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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

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GSM Architecture
DATA RATE 9.6 Kbps
SOURCE UWC
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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_at_wireless.att.net
• 1 BILLION SMS/day worldwide

SOURCE GEMBROOK SYSTEMS
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SMS in Banking
SOURCE GEMBROOK SYSTEMS
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Satellite Systems
GEO (22,300 mi., equatorial) high bandwidth,
power, latency MEO high bandwidth, power,
latency LEO (400 mi.) low power, latency
more satellites small footprint V-SAT (Very
Small Aperture) private WAN SATELLITE MAP
SOURCE WASHINGTON UNIV.
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Geostationary Orbit
SOURCE BILL LUTHER, FCC
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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 satellite

SOURCE NAVSTAR
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GPS Trilateration
DISTANCE MEASUREMENTS MUST BE VERY PRECISE LIGHT
TRAVELS 1018 FEET EACH MICROSECOND
SOURCE PETER DANA
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Automatic Vehicle Location (AVL)

• 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 demo CA
SOURCE TRIMBLE NAVIGATION
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Location-Aware Applications

• Vehicle tracking
• Firemen in buildings, vital signs, oxygen
  remaining
• Asset tracking
• Baggage
• Shoppers assistance
• Robots
• Corporate visitors
• Insurance
• Barges

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Wireless LAN

• Idea just a LAN, but without wires
• Not 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 power
• 802.11 from 2 Mb to 54 Mb
• Bluetooth
• UWB

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Wireless LAN Components
Extended Range Antenna
WaveLAN ISA (Industry Standard Architecture) Card
WavePOINT II Transmitter
Ethernet Converter
11 Mbps WaveLAN PCMCIA Card
SOURCE LUCENT
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Wireless LAN Configurations
CLIENT AND ACCESS POINT
WIRELESS PEER-TO-PEER
BRIDGING WITH DIRECTIONAL ANTENNAS
MULTIPLE ACCESS POINTS ROAMING
UP TO 17 KM !
SOURCE PROXIM.COM
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Bluetooth

• A standard permitting for wireless
  connection of
• Personal computers
• Printers
• Mobile phones
• Handsfree headsets
• LCD projectors
• Modems
• Wireless LAN devices
• Notebooks
• Desktop PCs
• PDAs

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Bluetooth Characteristics

• Operates in the 2.4 GHz Industrial-Scientific-Me
  dical (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.

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Bluetooth Devices
ALCATEL One TouchTM 700 GPRS, WAP
ERICSSON R520 GSM 900/1800/1900
ERICSSON BLUETOOTH CELLPHONE HEADSET
NOKIA 9110 FUJI DIGITAL CAMERA
ERICSSON COMMUNICATOR
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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

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Bluetooth Scatternets
Master / Slave
Slave
Piconet
ScatterNet
SOURCE KRISHNA BHOUTIKA
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Time-Modulated Ultra-Wideband (TM-UWB)

• Not a sinewave, but millions of pulses per second
• Time coded to make noise-likesignal
• Pulse position modulation

Spread Spectrum
SOURCE TIME DOMAIN
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Ultra Wideband Properties

• VERY low power 0.01 milliwatt
• Bluetooth 1 milliwatt (100 x UWB)
• Cellphone 500 milliwatts (50,000 x UWB)
• Range 30 to 300 feet
• Very small
• Low cost
• 100 Mbits/second
• Up to 500 Mbps for short distances(USB speed)
• No interference
• Secure

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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

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WAP Applications
Web Content Server
Non Mobile Internet User
WAP Gateway
Mobile Terminal
iNexware
Database Server
WAP simulator
SOURCE DANET
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iMode

• Telephone, pager, email, browser, location
  tracking, banking, airline tickets, entertainment
  tickets, games
• NTT DoCoMo (??? means anywhere)
• Japan is the wireless Internet leader

iMode FAQ
SOURCE EUROTECHNOLOGY JAPAN K.K.
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iMode

• Sits on top of packet voice/data transport
• As of July 31, 2003, 39 million subscribers
• 28,000 new ones per day
• 26 of Japan
• 3000 official sites
• 1000 application partners
• 40,000 unofficial sites
• Fee based on amountof data transmitted

SOURCES XML.COM, EUROTECHNOLOGY.COM
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iMode

• Phonetic text input (better for Japanese)
• SLOW 9.6 Kbps, but 3G will raise to 384 K
• Uses 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
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iMode Operation
DoCoMo Packet Network (PDC-P)
iMode Servers
HTTP
PACKET DATA
SOURCE SAITO SHIN
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Wireless Standards

• 802.11b (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 (1 Mbps _at_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
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Key Takeaways

• Mobile growing very rapidly
• Cell systems need large infrastructure
• Wireless LAN does not
• Content preparation is a problem
• Wireless business models largely unexplored
• Bandwidth, bandwidth, bandwidth

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Q
A

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Code Division
SOURCE JOCHEN SCHILLER
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Code Division
SOURCE JOCHEN SCHILLER
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Two CDMA Signals
2
ACTUAL SIGNAL AB
-2
SOURCE JOCHEN SCHILLER
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Recovering Data A From AB
1
-1
2
-(AB) CODE A
-2

0
INTEGRAL
1
1
SOURCE JOCHEN SCHILLER