Microsoft PowerPoint - W.wan.2.ppt

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1 Wireless WANs: From 1G to 4G Module W.wan.2 Shanghai Jiaotong University Shanghai, China University of New Mexico Albuquerque, NM, USA 1

2 W.wan.2-2 Wireless WAN: 1G 4G 1G AMPS 2G GSM Case Study: GSM & cdmaone (W.wan.3) 2.5G 3G Case Study: UMTS/W-CDMA (W.wan.4) 4G End of module W.wan.2

3 W.wan.2-3 Cellular network, 1G Analog-based European: NMT (Nordic Mobile Telephony) USA: AMPS (Advanced Mobile Phone Service), AT&T 1980s two 25-MHz bands allocated to AMPS Frequency reuse N=7, R = 2-20 km, K = 30KHz Each band split into two service providers A & B to encourage competition MHz MHz A: 12.5 MHz, uplink, B: 12.5 MHz uplink A: 12.5 MHz downlink B: 12.5 MHz downlink 12.5 M / 30 K = 416 channels 395 voice channels, FM/FDD 21 control data channels, FSK, 10 kbps An AMPS cell phone includes a NAM (Numeric Assignment Module) = telephone number + 32-bit serial number from manufacture

4 Cellular network, 1G W.wan.2-4 Analog-based, USA: AMPS (Advanced Mobile Phone Service) Initial setup operations MT power on, scan for the most powerful control channel, broadcast its NAM; BS hears MT s NAM, registers with MSC (Mobile Switching Center) MT updates its location every 15 minutes Making a call # to be called via access channel: MT BS MSC MSC schedule/assign up/down links channels Answering a call MT is alerted to incoming call via a paging channel Power saving Periodically sleep for 46.3 ms, then scan for paging channel Designed for GoS (Grade of service) of 2% blocking

5 Cellular network, 1G 2G W.wan.2-5 From 1G to 2G 1G Analog-based Frequency modulation Developed for a single application: voice Other services, such as fax, data, were defined as overlay services on top of the analog voice service 2G Digital-based TDMA & CDMA Integrated voice/data services provide encryption to prevent eavesdropping Error detection and correction, giving clear voice reception Allow channels to be dynamically shared by a number of users

6 W.wan.2-6 Wireless WAN: 1G 4G 1G AMPS 2G GSM Case Study: GSM & cdmaone (W.wan.3) 2.5G 3G Case Study: UMTS/W-CDMA (W.wan.4) 4G End of module W.wan.2

7 GSM cellular network, 2G W.wan.2-7 GSM (Global System for Mobile communications), 1991 R = 100m - 35 km, K = 200 KHz Integrated services with three domains: Service Category Teleservices Bearer services Supplementary services Service Telephone (13 kbps voice), emergency calls, SMS (short message service, 160 chars), FAX Circuit or packet switching: asynchronous data, (up to 9600 bps), synchronous (2.4, 4.8, 9.6 kbps) Call forwarding, conference call up to 7, callback

8 W.wan.2-8 GSM physical layer, 2G Frequency bands: MHz (uplink), MHz (downlink), Europe 1800 MHz, DCN (Digital Communication Network) 1900 MHz, USA 450 MHz, replacing analog NMT system K = 200 KHz, duplex channels are separated by 45 MHz (25 M 2x100KHz guard band) / 200 K = 124 channels Each 200 KHz kbps Each 200 KHz channel has 8 TDMA slots Each with ms duration 270.8/8 = 34 kbps + FEC 9.6 kbps Modulation: GMSK (Gaussian minimum shift keying)

9 W.wan.2-9 GSM frames & channels, 2G FDMA/TDMA; frames & bursts frequency MHz 124 channels (200 khz), downlink MHz 124 channels (200 khz), uplink higher GSM frame structures time GSM TDMA frame ms guard space GSM time-slot (normal burst) tail user data S Training S user data tail 3 bits 57 bits 1 26 bits 1 57 bits 3 guard space µs 577 µs

10 W.wan.2-10 GSM frames & channels, 2G Traffic for every 20 ms Logically 4 bursts every 24 bursts of traffic, adding 2 bursts of control (4 x 4.615ms) x (26/24) = 20ms Overhead added Application bits + coding payload Payload + guarding & training traffic Traffic + control physical carrier Application Payload Traffic Bits voice: data: 244 Bandwidth voice: 13 kbps 22.8 kbps 33.8 kbps data: 9.6 kbps

11 W.wan.2-11 GSM frames & channels, 2G Alignment of downlink & uplink If a MT receives data in time t on the downlink it access on the uplink at time t+3x.577ms so it does not need a full-duplex transmitter GSM logical channels = TCHs + CCHs Traffic channels (TCHs) Full-rate traffic channel (TCH/F), 22 kbps 13 kbps speech-coding voice traffic 9.6 or 4.8 or 2.4 kbps data traffic Half-rate traffic channel (TCH/H) 4.8 kbps voice traffic 4.8 or 2.4 kbps data traffic

12 W.wan.2-12 GSM frames & channels, 2G GSM logical channels = TCHs + CCHs Control channels (CCHs) BCCH (Broadcast control channel, downlink broadcast), Synchronization, frequency control, BS s ID & channel status DCCH (Dedicated control channel, two way) Call setup, location updates, call management Every call has its own allocated DCCH CCCH (Common control channel, one way) Downlink, paging channel for BS to alert MT for incoming call Uplink, random access channel for MT to initiate a new call Downlink, access grant channel for BS to inform MT of an allotted duplex channel for a call

13 W.wan.2-13 Other cellular network, 2G D-AMPS (Digital AMPS), USA Coexist with AMPS, also known as IS-54 Use AMPS carriers to deploy digital channels TDMA, six slots per frame cdmaone, South Korea & Hong Kong, 1993; USA, 1996 Also known as IS-95 (telecommunication Industry association interim Standard) Fully digital standard, in 800 MHz Only 2G CDMA, supports 4.8 & 14.4 kbps PDC (Personal digital cellular), Japan Based on D-AMPS

14 W.wan.2-14 Cellular markets, 2G USA Verizon CDMA and analog T-mobile GSM Sprint PCS CDMA Cingular China GSM, TDMA, analog 移动联通

15 W.wan.2-15 Wireless WAN: 1G 4G 1G AMPS 2G GSM Case Study: GSM & cdmaone (W.wan.3) 2.5G 3G Case Study: UMTS/W-CDMA (W.wan.4) 4G End of module W.wan.2

16 W.wan.2-16 Cellular network, 2.5G Data services over GSM SMS (Short Message Service) Each up to 160 characters in length Message transfer takes place over the control channel HSCSD (High-Speed Circuit-Switched Data) Circuit-switched protocol for larger file transfer & multimedia Occupies up to eight TDMA clots per user If using 4 slots, 57.6 kbps Asymmetrical, usually downlink demands more Increases blocking probability; Not efficient for burst data due to connection oriented protocol. Also, being charged by time not data.

17 W.wan.2-17 Cellular network, 2.5G Data services over GSM GPRS (General Packet Radio Service) TCP/IP packet service, no end-to-end connection Use all eight slots, up to kbps (depending on coding scheme) Allow for broadcast, multicast, and unicast Being charged on volume instead of on connection time Always on, no connection setup All time slots can be shared by the active users, up and down links are allocated separately On-demand scheduling, using idle time slots only Require more addition of infrastructure Can also be used for other TDMA systems Extended infrastructure for UMTS (3G)

18 W.wan.2-18 Cellular network, 2.5G Data services over GSM EDGE (Enhanced Data Rates for GSM Evolution) Also known as EGPRS (Enhanced GPRS) Instead of the binary GMSK, it uses 8-PSK modulation to triple the capacity compared to GSM, but more susceptible to errors Have 9 different modulation & coding schemes, each designed for a different quality condition Utilizing 200KHz narrow-band to approach 3G services Data services over AMPS CDPD (Cellular Digital Packet Data) Connectionless data packet service Be able to detect idle voice channels to transmit data packets Continuously hop channels without blocking a voice call

19 W.wan.2-19 Wireless WAN: 1G 4G 1G AMPS 2G GSM Case Study: GSM & cdmaone (W.wan.3) 2.5G 3G Case Study: UMTS/W-CDMA (W.wan.4) 4G End of module W.wan.2

20 W.wan.2-20 Cellular network, 2G 3G Uniform and continuous presentation of services, independent of location and access Aim at providing a virtual home environment Demand intelligent network to retrieval and update location information, handle handoffs, etc Evolution plan: 2G 3G Country Europe Existing 2G GSM 3G Standard W-CDMA (UMTS) USA Japan China cdmaone/is-95 IS-136 PDC cdma2000 UWC-136 W-CDMA (DoCoMo)

21 W.wan.2-21 IMT-2000: cellular network, 3G IMT-2000 (International Mobile Telecommunications) The system would become available in the year of 2000 Has data rates of 2000 kbps Operate in the 2000 MHz region Very nice, but dream didn t come true Service Upstream Downstream Example Switching Interactive Multimedia 256 kbps 256 kbps Video conf Circuit High multimedia 20 kbps 2 mbps TV Packet Medium multimedia 19.2 kbps 768 kbps Web Packet Switched data 43.2 kbps 43.2 kbps Fax Circuit Simple messaging 28.8 kbps 28.8 kbps packet Speech 28.8 kbps 28.8 kbps telephone circuit

22 W.wan.2-22 IMT-2000: cellular network, 3G Enabling technology for 3G Smart antennas Control a directional array with an advanced digital signal processing capability CDMA Can operate in the presence of interference Support very large bandwidth In practice, some disappointing performance Spectrum allocation IMT-2000 specified 2GHz spectrum could not be implemented Were partially or fully in use in many countries

23 IMT-2000: cellular network, 3G W.wan.2-23 Frequencies planned by IMT-2000 Original: (140MHz), (90MHz) Including two 30MHz MSS (Mobile Satellite Services) New addition: , , MHz ITU allocation (WRC 1992) Europe China Japan North America MHz GSM 1800 GSM 1800 DE CT IMT-2000 T D D UTRA FDD IMT-2000 cdma2000 PHS W-CDMA PCS MSS MSS MSS MSS T D D MSS IMT-2000 MSS UTRA FDD MSS IMT-2000 MSS cdma2000mss W-CDMA rsv. MSS MHz

24 W.wan.2-24 Cellular network, 3G Europe, W-CDMA (Wideband CDMA) Also known as UMTS (Universal Mobile Telecommunication System) CDMA-based Wideband K = 5 MHz (That is W meant, in GSM, K=200KHz) Interwork with GSM, handoff between WCDMA cell & GSM cell USA, cdma2000 An extension of cdmaone UWC-136 TDMA-based, an upgrade of IS-136 (2G) Watch out for new progress

25 W.wan.2-25 Cellular network, 3G 4G Dream of 4G in year of 2010? Seamless integration with wired IP networks High bandwidth, up to 100 mbps Ubiquity High-quality multimedia services Adaptive resource management Software-defined radio to make handsets efficient and flexible Programming functionality Modulation Coding MAC protocol Reconfigurable and extendable

26 W.wan.2-26 Wireless WAN: 1G 4G 1G AMPS 2G GSM Case Study: GSM & cdmaone (W.wan.3) 2.5G 3G Case Study: UMTS/W-CDMA (W.wan.4) 4G End of module W.wan.2 WLL & : module W.wan.5

EE Lecture 11 (Wireless Communications Systems)

EE Lecture 11 (Wireless Communications Systems) EE110300 Lecture 11 (Wireless Communications Systems) Contents ( ) (RF) (Antenna) m(t) m(t) 90 50 40 30 20 10 0 ( ) 10 300 330 0 30 60 270 90 240 210 180 150 120 (LAN) (VSAT ) (Pager) (Cellular Phone)