15-1©2010 Raj JainCSE574sWashington University in St. LouisWireless Cellular Networks: Wireless Cellular Networks: 1G and 2G1G and 2GRaj JainProfessor of Computer Science and Engineering Washington University in Saint LouisSaint Louis, MO 63130Audio/Video recordings of this lecture are available at:http://www.cse.wustl.edu/~jain/cse574-10/15-2©2010 Raj JainCSE574sWashington University in St. Louis Cellular Architecture Advanced Mobile Phone System (AMPS) Cellular Digital Packet Data (CDPD) Wireless Cellular Generations GSM CdmaOneOverviewOverview15-3©2010 Raj JainCSE574sWashington University in St. LouisCellular Frequency Reuse Cellular Frequency Reuse Cluster Size =4 Cluster Size =7 Cluster Size =1915-4©2010 Raj JainCSE574sWashington University in St. LouisCharacterizing Frequency ReuseCharacterizing 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) N = number of cells in repetitious pattern (Cluster)¾ Reuse factor¾ Each cell in pattern uses unique band of frequencies Hexagonal cell pattern, following values of N possible¾ 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= D/d = Ref: Derivation in Section 3.2 of Murthy and ManojN3NDRd15-5©2010 Raj JainCSE574sWashington University in St. LouisFrequency ReuseFrequency ReuseExampleExampleWhat 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 = √3ND = (3×12)1/2× 1 km= 6 km15-6©2010 Raj JainCSE574sWashington University in St. LouisCellular ArchitectureCellular ArchitectureMobileEquipmentSubscriberIdentityModuleBaseTransceiverStationBaseStationControllerHomeLocationRegisterVisitorLocationRegisterMobile servicesSwitchingCenterEquipmentIdentityRegisterAuthenti-cationCenterBaseTransceiverStationBaseStationControllerPSTNMobile Station Base Station Subsystem Network Subsystem15-7©2010 Raj JainCSE574sWashington University in St. LouisCellular Architecture (Cont)Cellular Architecture (Cont) Base station controller (BSC) and Base transceiver station (BTS) One BTS per cell. One BSC can control multiple BTS. ¾ Allocates radio channels among BTSs.¾ Manages call handoffs between BTSs. ¾ 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.15-8©2010 Raj JainCSE574sWashington University in St. LouisCellular Architecture (Cont)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.15-9©2010 Raj JainCSE574sWashington University in St. LouisAdvanced Mobile Phone System (AMPS)Advanced Mobile Phone System (AMPS) First generation analog system for North America Two 25-MHz bands are allocated to AMPS¾ Forward (Down): BS to mobile unit (869–894 MHz)¾ 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 operator21 Control/paging/access, and 395 traffic channels Each call uses two traffic channelsForward = Reverse + 45 MHz Control channels are 10 kbps digital channelsTraffic channels are analog using frequency modulation15-10©2010 Raj JainCSE574sWashington University in St. LouisCellular Digital Packet Data (CDPD)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 CallIdle ChannelData packets15-11©2010 Raj JainCSE574sWashington University in St. LouisWireless GenerationsWireless 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 based1G:AnalogVoice2G:DigitalVoice + Low Speed DataTDMAFDMA CDMAAMPS(U.S.)TACS(Europe)IS-54 D-AMPSIS-136 US TDMAGSMDCS1800DCS1900NA GSMIS-95IS-54 has analog control channel for compatibility with AMPS. Did not succeed.15-12©2010 Raj JainCSE574sWashington University in St. LouisWireless Generations (Cont)Wireless Generations (Cont) Acronyms:¾ Advanced Mobile Phone System (AMPS)¾ Total Access Communication System (TACS)¾ Interim Standard (IS) from Electronic Industry Association (EIA)/Telecommunications Industry Association (TIA)¾ Digital Advanced Mobile Phone System (D-AMPS)¾ Global system for mobile communication (GSM)¾ Digital Communication Network (DCN)¾ North America (NA)¾ Frequency/Time/Code division multiple access (FDMA/TDMA/CDMA)15-13©2010 Raj JainCSE574sWashington University in St. LouisPCSPCS 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:1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 MHzA D B E F CUnlic.PCSA D B E F CBlocks A, B are for major trading areas.Blocks C, D, E, F are for basic trading areas.Unlicensed PCS is nationwide.15-14©2010 Raj JainCSE574sWashington University in St. LouisCdmaOneCdmaOne 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
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