Overview of Current Communications Systems

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Overview of Current Communications Systems
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Growth of cellular telephone subscribers
throughout the world
1000
100
10
Worldwide subscribers (millions)
1
0.1
1985
1990
1995
2000
3
Second generation (2G) cellular methods
400
300
200
Subscribers Using Technology (millions)
100
0
1st Generation Analog
GSM
IS-136 PDC
IS-95 CDMA
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2G systems

• Most of todays cellular methods use second
  generation or 2G technologies
• While first generation systems relied on FDMA/FDD
  and only FM, second generation standards use
  digital modulation and TDMA/FDD or CDMA/FDD

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Most popular systems

• GSM (Global System Mobile)
• IS-136 (NADC) (North American Digital Cellular)
• PDC (Pacific Digital Cellular)
• IS-95 CDMA

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Key Specifications of leading 2G technologies
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. . . Key specifications of leading 2G
technologies
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. . . Key specifications of leading 2G
technologies
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2.5G Mobile radio networks

• Evolution from 2G ? 2.5G required to support
  increased data rates for modern Internet
  applications.
• 2.5G are new data-centric standard that can be
  overlaid on existing 2G technologies
• 2.5G supports new web browsing format language
  called WAP (Wireless applications Protocol)

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2.5G Mobile radio networks

• WAP enables standard web pages to be viewed in a
  compressed format ? suitable for small portable
  hand-held wireless devices.
• First developed in Japan by NTT-DoCoMo ? I-mode
  for PDC network - supports games, color graphics
  and interactive web pages using 9.6 kbps
• 25 million Japanese subscribers in 2001

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2.5G TDMA standards

• HSCSD (High Speed Circuit Switched Data) for
  2.5G GSM
• Allows a single mobile user to use more than one
  specific time slot as in GSM TDMA
• Increases application rate from 9,600 bps (2G
  GSM) to 14,400 bps (2.5G GSM)
• Ideal for streaming internet access or real-time
  interactive web sessions.
• Can be implemented by a software change at
  existing GSM base stations.

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. . . 2.5G TDMA standards GPRS (General Packet
Radio Service)

• GPRS for 2.5G GSM and IS-136
• Packet based data network suited for non-real
  time internet usage
• E-mail retrieving, faxes and where download ?
  upload
• GPRS can support more users that HSCSD, but in a
  bursty manner.

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. . . 2.5G TDMA standards EDGE (Enhanced Data
Ration for GSM or Global) for 2.5G GSM and
IS-136

• More advanced upgrade to GSM standard
• Regains additional hardware/software at existing
  base stations
• New digital modulation format (8-PSK/octal PSK)
• Raw data rate of 547.2 kbps possible with 8 GSM
  slots of a GSM channel are allowed for each user.

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2.5G CDMA standards

• IS-95B for 2.5G CDMA
• Medium data rate (MDR) service with throughput of
  115.2 kbps per user (8 x 14.4 kbps)
• Advanced handoff procedures allows mobiles to
  search different radio channels independently

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Third generation 3G wireless methods

• Unparalleled wireless access
• Multi Mbps Internet access using VoIP (Voice
  Over Internet Protocol), voice activated calls
• Ability to receive live music, interactive web
  sessions, voice and data access with multiple
  features at the same time, at all times

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. . . Third generation 3G wireless methods

• ITU (International Telecommunications Union)
  proposed
• A global frequency band in 2000 MHz range
• Single wireless communications standard for all
  countries in the world IMT-2000.
• World community remains split between
  GSM/IS-136/PDC and CDMA
• www.gsmworld.com
• www.edg.org

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2G - 3G evolution
GSM
IS-136 PDC
IS-95
GPRS
IS-95B
HSCSD
HSCSD
cdma2000-1xRTT
W-CDMA
Cdma2000-1xEV, DV, DO
EDGE
3GPP2
TD-SCDMA
cdma2000-3xRTT
3GPP
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3G CDMA standards

• 3G W-CDMA (UMTS - Universal Mobile
  Telecommunications System)
• Packet based wireless service which enables
  computers, entertainment devices, telephones to
  connect to internet anytime, anywhere.
• Packet data rates up to 2.048 Mbps per
  stationary user
• Broadcasting, VHE (Virtual Home Entertainment)
  m-commerce (mobile commerce), games, interactive
  video, virtual private technology - all possible
  from small portable wireless device

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. . . 3G CDMA standards

• 3G cdma2000 or cmda2000 IX
• New high data rate internet access with backward
  compatibility to IS-95 and IS-95B systems - 1.25
  MHz bandwidth
• Instantaneous data rate of 307 kbps in packet
  mode
• Both FDD (mobile radio) and TDD (in-building
  cordless) applications

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3G TDMA standards

• 3G TD-SCDMA (Time Division Synchronous Code
  Division Multiple Access)
• Developed by CATT (Chinese Academy of
  Telecommunications Technology) and Siemens.
• Adopted by ITU as one of 3G options in 1999
• Existing GSM - 3G evolution through additions of
  high data rate equipment in each GSM station -
  1.6 MHz bandwidth
• Utilizes smart antennas, spatial filtering and
  joint detection technologies

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Broadband wireless services

• Wireless Local Loop (WLL)
• Demand for broadband internet and computer
  access from businesses and homes
• Fixed wireless equipment have advantages such as
  fixed path between T-R
• Microwave or millimeter radio frequencies used
  gt28GHz - wave length is very small - small high
  gain antennas.
• Especially useful in developing nations with less
  telecommunications setup.

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Emerging applications and markets for broadband
services
Fiber Large business in high-density urban areas
Central Office
Backbone Network
Wireless Mid-market business outside the urban
core
Central Office
Copper/xDSL Small business
OC-3
Cable Residences
DAX
ISP
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Broadband wireless spectrum world-wide
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. . . Broadband wireless services

• Wireless Local Area Networks (WLANS)
• UNII (Unlicensed National Information
  Infrastructure) hand allocated by FCC for low
  power spread spectrum
• 5.150 - 5.35 Ghz, 5.725 - 5.825 GHz (1997)
• 902-928 Mhz, 2400-2483.5Mhz, 5.725-5.825 MHz
  (1980s end)
• IEEE 802.11 (1997) standard and (IEEE 802.11b)
  approved to provide guidelines for WLAN
  manufacturers

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IEEE 802.11 Wireless LAN
IEEE 802.11
2.4 GHZ
850 TO 950 NM
FHSS
DSSS
Diffuse IR
1 MbpsDBPSK
2 MbpsDQPSK
2 Mbps4GFSK
1 Mbps2GFSK
IEEE 802.11bExtension
11 MbpsDQPSK--CCKBPSK--PBCC
5.5 MbpsDQPSK--CCKBPSK--PBCC
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IEEE 802.11b Wireless LAN
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High Performance Radio Local Area Network
(HIPERLAN)

• Europe standard to provide similar capability to
  IEEE 802.11
• 5.2 GHz and 17.1Ghz frequency lands
• Up to 20 Mbps data rate at 50m range and vehicle
  speeds of 35km/hr
• Advanced standards include Europes ETSI-BRAN
  (Broadband Radio Access Network) and HIPERLAN/2.

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Personal Area Networks

• Ability to replace cables between devices with
  wireless short range connection
• Bluetooth operates in 2.4GHz ISM band
  (2900-2483.5MHz) with 1 MHz channel bandwidth
• Uses FH-SS TDD scheme with 1600 hps
• 1Mbps symbol rate using GSFSk modulation
• IEEE 802.15 sttandards committee is our
  international forum for developing Bluetooth and
  other PANS

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PAN Bluetooth standard