History of wireless communication

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History of wireless communication

• 1897 Marconi demonstrated transmission of radio
  waves to a ship at sea 29 km away
• 1915 Wireless telephony established-- Virginia
  and Paris
• 1920's Radio broadcasting became popular
• 1930's TV broadcasting began
• 1946 First public mobile telephone service in US
  
• 1960's Bell Labs developed cellular concept--
  brought mobile telephony to masses
• 1960s Communications satellites launched
• Late 1970's IC technology advances enable
  affordable cellular telephony-- ushers in modern
  cellular era

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Modern cellular standards

• 1979 NTT (Japan), FDMA, FM, 25 kHz channels,
  870-940 MHz
• 1983 AMPS (US), FDMA, FM, 30 kHz channels,
  824-894 MHz
• 1985 TACS (Europe), FDMA, FM, 25 kHz channels,
  900 MHz
• 1990 GSM (EuropeTDMA, GMSK, 200 kHz channels,
  890-960 MHz
• 1991 USDC/IS-54 (), US), TDMA, p/4 DQPSK, 30 kHz
  channels, 824-894 MHz
• 1993 IS-95 (US), CDMA, BPSK/QPSK, 1.25 MHz
  channels, 824-894 MHz and 1.8-2.0 GHz
• 1993 CDPD (US), ) Cellular Digital Packet Data(
  FHSS, GMSK, 30 kHz channels, 824-894 Mhz
• 2001 UMTS/IMT-2000 (3rd generation European
  cellular standard), supports data and voice (up
  to 2 Mbps), 1885-2025 MHz and 2110-2200 Mhz

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Wireless data standards

• IEEE 802.11 wireless LAN/ad-hoc networking, 1, 2
  or 11 Mbps, DSSS or FHSS with CSMA/CA
  RTS-CTS-ACK, 2.4 - 2.4835 GHz
• Bluetooth replacement for cables, short range
  (10 or 100 m), low power (1 or 100 mW), low cost,
  1 Mbps max data rate, local piconets with
  master-slave operation
• HomeRF wireless home networking, 150 feet range,
  up to 10 devices, SWAP protocol
• IEEE 802.15 wireless PAN, modes for low (lt 10
  kbps), medium (up to 200 kbps), and high (gt 20
  Mbps) data rates

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Facts about wireless communication

• Over 50 of US households have a cellular phone
  by 2003
• Over 170M wireless data users(2003) projected to
  reach 1.3 billion by 2004
• Over 200M mobile phone subscribers in Western
  Europe
• Global revenue from wireless portals predicted to
  grow from 700M to 42 billion by 2005
• Worldwide wireless subscribers to reach 1 billion
  by Q3 2002
• WLAN revenues predicted at 785M by 2004
• Forecasting a 59 percent growth rate for wireless
  usage in rural areas between 2000 and 2003

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Underlying concepts

• Electromagnetics
• Antennas, wave propagation, channel modeling
• Signals and systems
• Filtering, Fourier transforms, block-diagram
  design
• Digital signal processing
• Equalization, spread-spectrum, source coding
• Communications
• Modulation, noise analysis, channel capacity,
  channel coding

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Enabling technologies

• Digital integrated circuits
• RF generation devices (efficient power amps,
  sleep modes, improved oscillators, smart
  antennas)
• Source coding (data compression)
• Modulation (improved efficiency)
• Multiple-access techniques (increase number of
  users)
• Channel coding/forward error correction (improve
  probability of successful reception)
• Software programmable radios

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Switch
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PSTN/ISDN
Switch
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• ?????? Cellular System-Cell Phone
• ????? Mobile Communication System-Mobile phone

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Field strength contours
If the threshold of Rx is S5, and Rx is the
standard receiver for the system then the radius
R defines the cell size.
R
Cell size is then controlled by Tx power, Tx
antenna height, and Rx threshold.
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Base Station
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Base Station
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Base Station
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f1
downlink
Tx f2 Rx f1
uplink
Tx f1 Rx f2
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Frequency range
Lower Band-uplink
Upper Band-down link
f1
f3
f2
fn
f1
f3
f2
fn
f0
Centre Gap
Df
Tx - Rx Separation
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??????? ??????? Frequency Reuse

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f1
f1
D
R
R
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1
3
4
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Base Station
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Rx
Tx
Rx
two Rx antennas for diversity
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Base Station

• Each cell has a base station that consists of a
  tower and a small building containing the radio
  equipment

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Base Station

• Each cell has a base station that consists of a
  tower and a small building containing the radio
  equipment

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Cell phone towers come in all shapes and sizes
Weirdest one I have ever seen!!!
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1
R
Second tier
Interfering Cell
1
First tier
D
1
1
1
1
1
1
1
1
1
1
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Cell Splitting
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Cell Splitting - Method A
Original Cell
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Cell Splitting - Method B
Original Cell
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Cell Splitting - Method B
Original Cell
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Types of Power Control

• Open-loop power control
• Depends solely on mobile unit
• No feedback from BS
• Not as accurate as closed-loop, but can react
  quicker to fluctuations in signal strength
• Closed-loop power control
• Adjusts signal strength in reverse channel based
  on metric of performance
• BS makes power adjustment decision and
  communicates to mobile on control channel

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Estimate metric
Estimated Pilot Strength
Compare to reference metric
Reference Metric
Tx level1/Estimate
Relate tp Other Users
Issue power Control command
(a) Open-Loop Power Control
Receive command
(b) Closed-Loop Power Control
Adjacent transmitted power
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Traffic Engineering

• Ideally, available channels would equal number of
  subscribers active at one time
• In practice, not feasible to have capacity handle
  all possible load conditions
• For N simultaneous user capacity and L
  subscribers
• L lt N nonblocking system
• L gt N blocking system
• Performance criterion
• Probability that call request is blocked
• Capacity needed to achieve certain upper bound on
  prob. of blocking
• Average call completion delay
• Capacity needed to achieve a certain average delay

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Trunking

• In addition to frequency re-use, cellular network
  utilise the concept of trunking to support a
  very large number of subscribers using a much
  smaller number of channels (i.e. carriers)
• This is achieved due to the fact that MS access
  to a traffic channel in all cells is by demand
  assignment
• They must first negotiate with the network over a
  signalling channel to gain access to a traffic
  channel for the duration of a call
• As with all trunked systems, there is always the
  possibility that subscribers will not be able to
  access the network due to the limited number of
  traffic channels available

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Hand-Over

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F1
F2
F3
F4
F1
F2
F1
F2
F3
F2
F4
F3
F4
F1
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GSM overview
OMC, EIR, AUC
fixed network
HLR
GMSC
NSS with OSS
VLR
MSC
MSC
VLR
BSC
MS
BSC
MS
MS
BTS
RSS
MS
MS
radio cell
BTS
BTS
BTS
BTS
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1960's Bell Labs developed cellular concept
1979 NTT (Japan)
1983 AMPS (US),
1st G
1985 TACS (Europe(
1990 GSM (Europe(
1991 IS-54 (US), TDMA
1990 PDC (Japan)
2nd G
1993 IS-95 (US), CDMA,
1993 CDPD (US), FHSS, GMSK
2000 CDMA2000
3rd G
2003 WCDMA
2003 TD-SCDMA China
4th G
2010 ?, 4G
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Wireless systems overview of the development
wireless LAN
cordlessphones
cellular phones
satellites
1980CT0
1981 NMT 450
1982 Inmarsat-A
1983 AMPS
1984CT1
1986 NMT 900
1987CT1
1988 Inmarsat-C
1989 CT 2
1991 DECT
1991 D-AMPS
1991 CDMA
199x proprietary
1992 GSM
1992 Inmarsat-B Inmarsat-M
1993 PDC
1997 IEEE 802.11
1994DCS 1800
1998 Iridium
1999 802.11b, Bluetooth
2000GPRS
2000 IEEE 802.11a
analogue
2001 IMT-2000
digital
200? Fourth Generation (Internet based)
4G fourth generation when and how?
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Introduction

• GSM
• formerly Groupe Spéciale Mobile (founded 1982)
• now Global System for Mobile Communication
• Pan-European standard (ETSI, European
  Telecommunications Standardisation Institute)
• The European Telecommunication Standards
  Institute (ETSI) standardised the Global System
  for Mobile communications (GSM).
• ETSI originally defined GSM as a European digital
  cellular telephony standard.
• The GSM interfaces defined by ETSI lay the
  ground-work for a multivendor network approach to
  digital mobile communication.
• GSM offers users good voice quality, call
  privacy, and network security.

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Introduction - cont.

• simultaneous introduction of essential services
  in three phases (1991, 1994, 1996) by the
  European telecommunication administrations
  (Germany D1 and D2)
• GSM networks on air (August 2001) is 400 in 171
  countries supporting 564.6 million users.
• World user growth expected 800.4 million by end
  of July 2001.

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  ???. PIN ?? ??? ?? ?? ???? ????? ?????? ?????
  ????? ??? ???? ???? ??? PUK ?? ?? ??? ??? ?? ????
  ??.

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• ????? ????? ????(card Serial Number)
• PINPersonal Identity Number
• PUKPIN Unblocking Key
• ???? ????? ???? Ki ???? ????? ????
• ?????? ?? ????? ???? ?? ???? IMSI ???? ??? ?? ??
  ???.
• IMSIMCCMNCMSIN
• ?? ???? MCC ?? ???? 3 ??? ?? ??? ???.
• ?? ???? ?????? MNC ?? ???? 2 ??? ?? ??? ???.
• ??? ?????? ?? ??? TMSI ?? ???? ???? ????? ?? ???
  ?? ???? ????? ?? IMSI ?? ??? ?? ???.

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??? ????

• ??? ????? ?? ??? ?? MSRN(Mobile Station Roaming
  Number) ?? ????? ISDN ?? ??? ????? ????.
• ??? ?????? ??? ????? ?? ??? ?? ?? ?? ?????
  ??????? ??? ?????? ????? ?????? ????? ?? IMEI
  (International Mobile Equipment Identity) ??????
  ?? ???.