Wireless Cellular Networks 1G and 2G Raj Jain Professor of Computer Science and Engineering Washington University in Saint Louis Saint Louis MO 63130 Audio Video recordings of this lecture are available at http www cse wustl edu jain cse574 10 Washington University in St Louis CSE574s 15 1 2010 Raj Jain Overview Cellular Architecture Advanced Mobile Phone System AMPS Cellular Digital Packet Data CDPD Wireless Cellular Generations GSM CdmaOne Washington University in St Louis CSE574s 15 2 2010 Raj Jain Cellular Frequency Reuse Cluster Size 4 Cluster Size 7 Cluster Size 19 Washington University in St Louis CSE574s 15 3 2010 Raj Jain Characterizing Frequency Reuse D minimum distance between centers of cells that use the same band of frequencies called co channels R radius of a cell d distance between centers of adjacent cells d R 3 R N number of cells in repetitious pattern Cluster d Reuse factor D Each cell in pattern uses unique band of frequencies Hexagonal cell pattern following values of N possible N I2 J2 I x J I J 0 1 2 3 Possible values of N are 1 3 4 7 9 12 13 16 19 21 D R 3N D d N Ref Derivation in Section 3 2 of Murthy and Manoj Washington University in St Louis CSE574s 15 4 2010 Raj Jain Frequency Reuse Example What would be the minimum distance between the centers of two cells with the same band of frequencies if cell radius is 1 km and the reuse factor is 12 D R 3N D 3 12 1 2 1 km 6 km Washington University in St Louis CSE574s 15 5 2010 Raj Jain Cellular Architecture Base Transceiver Station Subscriber Identity Module Mobile Equipment Base Station Controller Home Location Register Base Station Controller Mobile services Switching Center Base Transceiver Station Equipment Identity Register Mobile Station Base Station Subsystem Washington University in St Louis CSE574s 15 6 Visitor Location Register PSTN Authentication Center Network Subsystem 2010 Raj Jain Cellular Architecture Cont Base station controller BSC and Base transceiver station BTS One BTS per cell One BSC can control multiple BTS Allocates radio channels among BTSs Manages call handoffs between BTSs Controls handset power levels Mobile Switching Center MSC connects to PSTN and switches calls between BSCs Provides mobile registration location authentication Contains Equipment Identity Register Washington University in St Louis CSE574s 15 7 2010 Raj Jain Cellular Architecture Cont Home Location Register HLR and Visitor Location Register VLR provide call routing and roaming VLR HLR MSC functions are generally in one equipment Equipment Identity Register EIR contains a list of all valid mobiles Authentication Center AuC stores the secret keys of all SIM cards Each handset has a International Mobile Equipment Identity IMEI number Washington University in St Louis CSE574s 15 8 2010 Raj Jain Advanced Mobile Phone System AMPS First generation analog system for North America Two 25 MHz bands are allocated to AMPS Forward Down BS to mobile unit 869 894 MHz Reverse Up Mobile to base station 824 849 MHz In each market two operators are accommodated Each operator is allocated only 12 5 MHz in each direction Channels spaced 30 kHz apart 416 channels per operator 21 Control paging access and 395 traffic channels Each call uses two traffic channels Forward Reverse 45 MHz Control channels are 10 kbps digital channels Traffic channels are analog using frequency modulation Washington University in St Louis CSE574s 15 9 2010 Raj Jain Cellular Digital Packet Data CDPD Allows data to use idle cellular channels Data hops from one channel to next as the channels become busy or idle Quickly hops off a channel grabbed by cellular system In practice dedicated channels Voice Call Idle Channel Washington University in St Louis CSE574s 15 10 Data packets 2010 Raj Jain Wireless Generations 1G Analog Cellular Phones Needs a modem 9 6 kbps max 2G Digital Cellular Phones No modem required 19 3 kbps max GSM CDMA Clear voice Encryption 2 5G GPRS 144kbps Data only 3G Future high speed data with Voice 64 kbps to 2 Mbps 4G IP based 1G Analog 2G Digital Voice Voice Low Speed Data FDMA TDMA CDMA AMPS TACS IS 54 D AMPS GSM IS 95 U S Europe IS 136 US TDMA DCS1800 IS 54 has analog control channel for compatibility DCS1900 with AMPS Did not succeed NA GSM 2010 Raj Jain Washington University in St Louis CSE574s 15 11 Wireless Generations Cont Acronyms Advanced Mobile Phone System AMPS Total Access Communication System TACS Interim Standard IS from Electronic Industry Association EIA Telecommunications Industry Association TIA Digital Advanced Mobile Phone System D AMPS Global system for mobile communication GSM Digital Communication Network DCN North America NA Frequency Time Code division multiple access FDMA TDMA CDMA Washington University in St Louis CSE574s 15 12 2010 Raj Jain PCS Personal Communication Service PCS Personal User specific vs location specific Phone for user regardless of his her location FCC spectrum for PCS requires digital service PCS Digital Cellular IS 136 GSM or CDMA PCS Spectrum A D B E F C Unlic PCS A D B E F C 1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 MHz Blocks A B are for major trading areas Blocks C D E F are for basic trading areas Unlicensed PCS is nationwide Washington University in St Louis CSE574s 15 13 2010 Raj Jain CdmaOne Code Division Multiple Access CDMA CdmaOne 2G IS 95a CdmaTwo IS 95b CDMA2000 3G Each user uses the entire spectrum 22 40 calls per carrier Different spreading code for each user Neighboring cells can use the same frequency spectrum but different codes Precise power control is critical Can serve more users than TDMA or GSM Data users limited to 4 8 and 14 4 kbps CdmaTwo extension offers up to 115 2 kbps Verizon Sprint networks are CdmaOne networks Washington University in St Louis CSE574s 15 14 2010 Raj Jain GSM Global System for Mobile Communication GSM 1982 Started as Groupe Special Mobile by Conference of European Posts and Telecom CEPT Good speech quality ISDN compatibility and fraud secure Specs completed in 1990 Service began in 1992 900 MHz operation in Europe UK allocated 1800 MHz and adapted GSM standard as DCS 1800 DCS 1800 also used in Russia and Germany Washington University in St Louis CSE574s 15 15 2010 Raj Jain GSM Cont FCC allocated 1900 MHz for PCS Many carriers adapted GSM standard as DCS 1900 or North American GSM VoiceStream Powertel and Bellsouth Mobility use NA GSM 280 GSM networks in 100 countries worldwide Washington University in St Louis
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