PCS 1 Reference Wireless and Mobile Network Architectures Y-Bing Lin and Imrich Chlamtac Wiley Computer Publishing 2
Outlines Introduction PCS Architecture Cellular Telephony Cordless Telephony and Low-Tier PCS Third-Generation Wireless Systems Summary 3 Introduction 4
PCS Personal Communications Services (PCS) refers to a wide variety of wireless access and personal mobility services. PCS systems can connected to Public Switched Telephone Network (PSTN). Goal of PCS enabling communications with a person at anytime, at any place and in any terminal form. 5 PCS Revolution First Generation Second Generation Third Generation High-tier Digit Cellar Systems JTACS TACS NMT GSM JDC Mobile Satellite GSM+ IMT-2000 AMPS NADC PCS Low-tier Telecommunication Systems PHS PACS CT0/1 CT2 DECT 6
PCS Revolution First Generation Second HSCSD: Generation High Speed Circuit Third Switched Generation Data GPRS: packet switching JTACS Mobile Satellite JDC High-tier TACS 4G? Digit Cellar GSM GSM+ WLAN+GPRS NMT Systems IMT-2000 AMPS NADC PCS Low-tier Telecommunication Systems CT0/1 CT2 PHS PACS ITU: International Telecommunications Union DECT 7 Examples of Wireless Communications Systems (1/4) High-tier digital cellular systems For vehicular and pedestrian services Europe Global System for Mobile Communication (GSM), Digital Communication System-1800 (DCS1800) USA IS-136 TDMA based Digital Advanced Mobile Phone Service (DAMPS) IS-95 CDMA-based cdmaone System Japan Personal Digital Cellular (PDC) 8
Examples of Wireless Communications Systems (2/4) Low-tier telecommunication systems For residential, business, and public cordless access applications Europe, Asia Cordless Telephone 2 (CT2) Digital European Cordless Telephone (DECT) USA Personal Access Communications Systems (PACS) Japan Personal Handy Phone System (PHS) 9 Examples of Wireless Communications Systems (3/4) Wideband wireless systems To accommodate Internet and multimedia services. cdma2000 (evolved from cdmaone) W-CDMA (proposed by Europe) TD-SCDMA (proposed by China/Europe) 10
Examples of Wireless Communications Systems (4/4) PCS umbrella Paging systems (90 s BB call) Specialized Mobile Radio (taxi calling) Mobile-satellite system Unlicensed industrial, scientific, and medical ISM band technologies, as well as wireless local area networks (WLANs) 11 PCS Architecture 12
PSTN Public Switched Telephone Network Switch Taichung Taipei subscriber loopswitch trunk Switch Trunk: 1. SS7 2. voice Ex.: Chunghwa Telecom 13 PLMN Public Land Mobile Network PLMN PSTN Ex.: Far Eastone Telecom 14
The Basic PCS Architecture Public Land Mobile Network MSC Mobile Switching Center Radio Network Switch for Mobile Applications Mobility Database Wireline Transport Network Base Station Controller BS: base station Mobile Station Base Transceiver Station 15 PCS Architecture Each PCS technology has similar architectures which consists two parts Radio Network MS (Mobile Station) BS (Base Station) System Wireline Transport Network MSC (Mobile Switching Center) The Mobility Database connected to MSC is used to track the locations of mobile station. 16
Mobile Station (MS) Handset, mobile phone, subscriber unit, portable (low-tier systems) 行 17 Base Station (BS) The radio coverage of a BS is called a Cell. The BS system is partitioned into a controller radio transmitters/receivers The BSs usually reach the wireline core network via land links or dedicated microwave links. 18
GSM Antenna 19 GSM Base Station 20
Cellular Concept cluster cell sector 21 Cellular Concept In AMPS 12-group frequency cluster 7-group cluster, cell? 理論 1 cells, : GSM 例, cell size, capacity no. of cells (cell size ) Frequency reuse factor, system capacity (handoff, location tracking) Cell size time 22
Duplex Technologies Down-link: BS to handset Up-link: handset to BS Two duplex Technologies: FDD Frequency Division Duplex TDD Time Division Duplex 23 FDD Frequency A1 talks to A2 B1 talks to B2 C1 talks to C2 Down Link A2 talks to A1 B2 talks to B1 C2 talks to C1 Up Link Time 24
TDD Frequency A2 talks to A1 B2 talks to B1 C2 talks to C1 A1 talks to A2 B1 talks to B2 C1 talks to C2...... Time 25 Multiple Access Technology FDMA Frequency Division Multiple Access TDMA Time Division Multiple Access CDMA Code Division Multiple Access 26
Frequency FDMA 30kHz for AMPS Time 27 Frequency TDMA 200kHz for GSM 4.615 ms/frame 8 time slots for GSM Time 28
CDMA (1/2) Frequency 1.25MHz for IS-95 20 ms/frame 32 channels 29 CDMA (2/2) Code Division Multiple Access (CDMA) Direct Sequence Spread Spectrum (DSSS) Frequency Hopping Spread Spectrum (FHSS) In DS-CDMA, every signal is processed with PN sequence (pseudo-noise sequence). Faster-rate, wide-bandwidth digital signal Each PN sequence is a unique orthogonal code. 30
Spread Spectrum Correlation Process Data Signal Received Signal + Wideband Interference Recovered Data Signal Direct Sequence Spread W Hz Direct Sequence Despread 0 f 0 f 0 f : Desired Signal : Interference 31 Cellular Telephony High-tier cellular telephone 32
1920 年 律 車 行,. 1930,. 1930 年, FM 行., 量 行. 1940 年, cellular 念, 了行 率. cellular : 率, 率 率 (so cost 降 ), 切, handover 念 ( 行 不 切 ). 33 1G Cellular Telephony Advanced Mobile Phone Service (AMPS) Total Access Communication System (TACS) NTT (Nippon Telephone & Telegraph), JTACS (1988), NTACS (1993) C450 34
2G Cellular Telephony Global System for Mobile Communications (GSM) EIA/TIA IS-136 Digital Cellular System EIA/TIA IS-95 Digital Cellular System Japanese Digital Cellular (JDC) in Japan 35 Global System for Mobile Communications (GSM) (1/2) Digital cellular system Groupe Special Mobile of Conference Europeenne des Posts et Telecommunications (CEPT) and European des Postes et Telecommunications (ETSI, ) 陸 路 立類 ISDN 路 數 利 數 來 便 SIM 料 GSM PCS. GSM 36
Global System for Mobile Communication (GSM) (2/2) Frequency carrier is divided into 8 time slots Every pair of radio transceiver-receiver supports 8 voice channels. GSM Mobile Application Part (MAP) for roaming management ( 理 ) Digital switch can provide many applications: Example: point-to-point short messaging, group addressing, call waiting, multiparty services 37 EIA/TIA IS-136 Digital Cellular System (1/2) AMPS EIA/TIA: Electronic Industries Association and Telecommunication Industry Association : IS-54 Digital AMPS (DAMPS), or North American TDMA (NA-TDMA), IS-54 IS-136 (IS-54 is never used) The same spectrum used by AMPS 3 times of capacity of AMPS TDMA/FDD 來,,.. 量 AMPS 38
EIA/TIA IS-136 Digital Cellular System (2/2) 2 types of channel usage: Full-rate: use 2 timeslot for a voice channel Half-rate: use 1 timeslot for a voice channel Digital switch can provide many applications: Example: point-to-point short messaging, broadcast messaging, group addressing, private user groups 39 EIA/TIA IS-95 Digital Cellular System (1/2) Qualcomm cdmaone in USA since 1993(~1996) Korea in April, 1996. Switch PLMN PSTN 40
EIA/TIA IS-95 Digital Cellular System (2/2) CDMA/DSSS for the air interface. A shared 1.25 MHz channel bandwidth User signals distinguished with different codes MSs links to many BSs during phone calls. IS-41 for core network 41 Comparison of Cellular Systems System AMPS GSM DCS1800 IS-136 IS-95 CDMA JDC Region,,, Duplex FDD FDD FDD FDD FDD MAC FDMA FDMA TDMA FDMA TDMA FDMA CDMA FDMA TDMA Downlink (MHz) 870-890 935-960 1805-1880 869-894 869-894 810-826 Uplink (MHz) 825-845 890-915 1710-1785 824-849 824-849 940-956 Carrier 30kHz 200kHz 30kHz 1.25MHz 25kHz Channels 1 8 6 32 3 Speech rate 10 kps 13 kps 7.95kps 8 kps 11.2 kps Channel bit rate 270.833 kps 48.6 kps 1228.8 kps 42 kps 42
Cellular Characteristics The characteristics of the cellular system: Support high mobility Large coverage area High transmission power of BS and handset High signal process power (for handset) Low voice quality High network complexity Microcell is developed for: Low transmission power Low base station cost 43 Low-Tier PCS 44
Examples of Low-Tier PCS Cordless Telephone, Second Generation (CT2) Digital European Cordless Telephone (DECT) Personal Handy Phone System (PHS) Personal Access Communications System (PACS) 45 Low-tier PCS Characteristics The characteristics of the low-tier system: Low transmission power Long talk time Small coverage area Large no. of base station Low transmission delay High voice quality Low mobility Low network complexity Low cost 46
Characteristics of Cellular and Cordless Low-Tier PCS Technologies Systems HIGH-TIER CELLULAR LOW-TIER PCS CORDLESS Cell Size Large(0.5-35 Km) Medium(50-500 m) Small(50-100m) User Speed High(<=257Km/hr) Medium(<=96Km/hr) Low(<=48Km/hr) Coverage Area Large/Continuous macro cells Medium micro and picocells Small/Zonal picocells Handset Complexity High Low Low Handset power consumption High (100-800mW) Low (5-10mW) Low (5-10mW) Speech Coding Rate Low (8-13Kbps) High (32Kbps) High (32Kbps) Delay or Latency High (<= 600ms) Low (<= 10ms) Low (<=20ms) 47 Third-Generation Wireless System 48
Generations of Wireless Systems First Generation System: AMPS Analog voice calls Second Generation Systems: GSM, IS-136, IS-95, and low-tier systems Digital speech with low-bit-rate data services Third-Generation: Better system capacity High-speed and wireless Internet access (to 2Mbps) Wireless multimedia services (audio and video) All IP mobile 49 Third-Generation Wireless Systems 2.5G: GPRS and HSCSD Bridge 2G into 3G The new features for 3G includes High bit rates, QoS, Bit rates dependent on distance 50
Third-Generation Wireless Systems 3G data rate requirement Vehicular: 144Kbps Pedestrian: 384Kbps Indoor: 2Mbps 51 3G Revolution 2 G 2.5G 3G America IS-95A IS-95B cdma2000 1x Cdma2000 3xMC IS-136? 1xEV-DO 1xEV-DV High Speed Downlink Packet Access EDGE Europe GSM GSM GPRS UMTS UMTS/ HSDPA Japan PDC P-PDC W-CDMA 52
Summary PCS Architecture Cellular Telephony Cordless Telephony and Low-Tier PCS Third-Generation Wireless Systems 53 4G ITU 2003 年 6 4G Vehicular : 100Mbps Motionless 1Gbps 54