Wireless WAN ห วข อ เคร อข ายไร สายระยะไกล. Cellular Network WiMAX

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1 Wireless WAN เคร อข ายไร สายระยะไกล 1 ห วข อ Cellular Network WiMAX 2

2 Cellular Network - Architecture Radio tower PSTN Telephone Network Mobile Switching Center 3 Cell 1 A Cellular Network Cell 2 Mobile Telephone Switching Center (MTSC) Public Switched Telephone Network (PSTN) HLR VLR Mobile User Cordless connection Wired connection Base Transceiver Station (BTS) HLR = Home Location Register 4 VLR = Visitor Location Register

3 Cellular System Cell 1 Cell 2 Mobile Telephone Switching Center (MTSC) HLR VLR Public Switched Telephone Network (PSTN) Handoffs (typically 30 mseconds): 1. At any time, mobile station (MS) is in one cell and under the control of a BS 2. When a MS leaves a cell, BS notices weak signal 3. BS asks surrounding BSs if they are getting a stronger signal 4. BS transfers ownership to one with strongest signal 5. MTSC assigns new channel to the MS and notifies MS of new boss 5 Cellular networks: From 1G to 3G 1G: First generation wireless cellular: Early 1980s Analog transmission, primarily speech: AMPS (Advanced Mobile Phone Systems) and others 2G: Second generation wireless cellular: Late 1980s Digital transmission Primarily speech and low bit-rate data (9.6 Kbps) High-tier: GSM, IS-95 (CDMA), etc Low-tier (PCS): Low-cost, low-power, low-mobility e.g. PACS 2.5G: 2G evolved to medium rate (< 100kbps) data 3G: Broadband multimedia 144 kbps kbps for high-mobility, high coverage 2 Mbps for low-mobility and low coverage 6

4 Data Rates 2 Mbps 1G to 3G 1 Mbps 100 Kbps 10 Kbps 1 Kbps 1G (<1Kbps) 2G (9.6Kbps) 2.5G (10-150Kbps) 3G (144Kbps to 2Mbps) Years Very Basic Cellular/PCS Architecture Public Switched Telephone Network Mobility Database Base Station Controller Mobile Switching Center (MSC) Radio Network Base Station (BS) Mobile Station Personal Communications Service 8

5 Duplex Communication - FDD FDD: Frequency Division Duplex Mobile Terminal M Forward Channel Reverse Channel Base Station B Forward Channel and Reverse Channel use different frequency bands 9 Access Methods Frequency FDMA Frequency Time Frequency Time TDMA CDMA Time 10

6 Clusters A cluster is a group of cells No channels are reused within a cluster A seven Cell Cluster 11 Frequency Reuse Cells with the same number have the same set of frequencies Frequency Reuse 12

7 Frequency Reuse using 7 frequencies allocations f7 f6 f2 f1 f5 f7 f6 f3 f4 f2 f1 f5 f7 f6 f3 f4 f2 f1 f5 f7 f6 f3 f4 f2 f1 f5 f7 f6 f3 f4 f2 f1 f5 f3 f4 Each cell is generally 4 to 8 miles in diameter with a lower limit around 2 miles. 13 Cell Splitting Allows urban centres to be split into as many areas as necessary for acceptable service levels in heavy-traffic regions, while larger, less expensive cells can be used to cover remote rural regions 14

8 Cellular Concept with Sectors frequency re-use base station 15 Hand-off The final obstacle in the development of the cellular network involved the problem created when a mobile subscriber moved from one cell to another during a call 16

9 Looking to PCS from different Angles PSTN (Telephone Network) Internet Wireless Access Mobile Users -Cell phone users -Cordless phone users Telecom People View Mobile Users -Laptop users -Pocket PC users -Mobile IP, DHCP enabled computers Data Networking People View 17 Telecom and Data Networking Telecom Interest Data Networking Interest - Voice Transmission - Frequency Reuse - Handoff Management -Location Tracking -Roaming -QoS -GSM, CDMA, Cordless Phones, -GPRS, EDGE -Radio Propagation -Link Characteristics -Error Models -Wireless Medium Access (MAC) - Error Control -Data Transmission -Mobile IP (integrating mobile hosts to internet) -Ad-hoc Networks -TCP over Wireless -Service Discovery 18

10 Major Mobile Radio Standards - USA Standard Type Year Intro Multiple Access Frequency Band (MHz) Modulation Channel BW (KHz) AMPS Cellular 1983 FDMA FM 30 USDC Cellular 1991 TDMA DQPSK 30 CDPD Cellular 1993 FH/Packet GMSK 30 IS-95 Cellular/PCS 1993 CDMA QPSK/BPSK 1250 FLEX Paging 1993 Simplex Several 4-FSK 15 DCS-1900 (GSM) PCS 1994 TDMA GMSK 200 PACS Cordless/PCS 1994 TDMA/FDMA DQPSK Major Mobile Radio Standards - Europe Standard Type Year Intro Multiple Access Frequency Band (MHz) Modulation ETACS Cellular 1985 FDMA 900 FM 25 Channel BW (KHz) NMT-900 Cellular 1986 FDMA FM 12.5 GSM Cellular/PCS 1990 TDMA GMSK 200KHz C-450 Cellular 1985 FDMA FM ERMES Paging 1993 FDMA4 Several 4-FSK 25 CT2 Cordless 1989 FDMA GFSK 100 DECT Cordless 1993 TDMA GFSK 1728 DCS-1800 Cordless/PCS 1993 TDMA GMSK

11 2G Technologies Uplink Frequencies (MHz) Downlink Frequencies cdmaone (IS-95) GSM, DCS-1900 IS-54/IS-136 PDC (Cellular) (US PCS) MHz (US Cellular) MHz (US PCS) MHz (Eurpe) (US PCS) (Europa) (US PCS) Deplexing FDD FDD FDD Multiple Access CDMA TDMA TDMA Modulation BPSK with Quadrature Spreading GMSK with BT= MHz, 1500 Mhz (Japan) (US PCS) MHz (Cellular) (US PCS) 800 MHz, 1500 MHz (Japan) π/4 DQPSK Carrier Seperation 1.25 MHz 200 KHz 30 KHz (IS-136) (25 KHz PDC) Channel Data Rate Mchips/sec Kbps 48.6 Kbps (IS-136) 42 Kbps (PDC) Voice Channels per carrier Speech Coding CELP at 13Kbps EVRC at 8Kbps RPE-LTP at 13 Kbps VSELP at 7.95 Kbps 21 GSM and CDMA Coverage Map Worldwide 22

12 WiMax Worldwide Interoperability for Microwave Access Last mile wireless broadband access Alternative to cable and DSL Deliver data, voice, video Support hundreds to thousands of homes/business Standards History First standard based on proprietary implementations of DOCSIS/HFC architecture in wireless domain c (2002) Amendment WiMAX System Profiles GHz (Dec 2001) a (Jan 2003) REVd ( ) (Oct 2004) Original fixed wireless broadband air Interface for GHz: Line-of-sight only, Point-to- Multi-Point applications Extension for 2-11 GHz: Targeted for nonline-of-sight, Point-to-Multi-Point applications like last mile broadband access Adds WiMAX System Profiles and Errata for 2-11 GHz e ( ) (Dec 2005) MAC/PHY Enhancements to support subscribers moving at vehicular speeds 24

13 Wireless RMF Spectrum 25 Applications of Standards 26

14 Scope of Standards 27 Physical Layer Summary Designation Applicability MAC Duplexing WirelessMAN-SC GHz Licensed Basic TDD, FDD, HFDD WirelessMAN-SC 2-11 GHz Licensed Basic, (ARQ), (STC), (AAS) WirelessMAN-OFDM WirelessMAN-OFDMA 2-11 GHz Licensed Basic, (ARQ), (STC), (AAS) 2-11 GHz Licenseexempt Basic, (ARQ), (STC), (DFS), (MSH), (AAS) 2-11 GHz Licensed Basic, (ARQ), (STC), (AAS) 2-11 GHz Licenseexempt Basic, (ARQ), (STC), (DFS), (MSH), (AAS) TDD, FDD TDD, FDD TDD TDD, FDD TDD 28

15 Channel Characteristics GHz Very weak multipath components (LOS is required) Rain attenuation is a major issue Single-carrier PHY 2-11 GHz Multipath NLOS Single and multi-carrier PHYs 29 General Downlink Frame Structure Downlink Interval Usage Code (DIUC) indicates burst profile 30

16 General Uplink Frame Structure Uplink Interval Usage Code (UIUC) indicates burst profile 31 Frame Structure Another View 32

17 Network Entry Process 33 Connections /WiMAX is connection oriented For each direction, a connection identified with a 16 bit CID Each CID is associated with a Service Flow ID (SFID) that determines the QoS parameters for that CID 34

18 WiMAX connection 35 Wireless PAN & Wireless Sensor เคร อข ายไร สายส วนบ คคลและเคร อข ายตรวจจ บ 36

19 ห วข อ Bluetooth (IEEE ) Zigbee (IEEE ) 37 Bluetooth IEEE Adopted the Bluetooth MAC and PHY specifications IEEE and Bluetooth are almost identical regarding physical layer, baseband, link manager, logical link control and apdation protocol, and host control interface 38

20 Usage three major applications Landline Data/Voice Access Points (internet access) Cable Replacement Personal Ad-hoc Networks 39 Bluetooth Specifications 2.4 GHz ISM Unlicensed band Microwave ovens also use this band Frequency Hopping Spread Spectrum Avoid interference 23/79 channels 1 MHz per channel 1 Mbps link rate (GFSK modulation) Fast frequency hopping and short data packets avoids interference Nominally hops at 1600 times a second (vs. 2.5 hops/sec in IEEE ) 625us per hop (366us for data only) 3200 times a second during inquiry and paging modes Multiple uncoordinated networks may exist and cause interference CVSD (Continuous Variable Slope Delta Modulation) voice coding (FEC) enables operation at high bit error rates 40

21 ISM Unlicensed Band 79 channels in 2.4GHz (in USA and most Europe) Guard band Guard band Licensed band GHz 79 hopping channels Licensed band 2.4 GHz ISM unlicensed band 41 Transmit Power transmit power and range o 0 dbm (up to 20dbm with power control) o m Power Class Max Output Min Output Power Control mW (20dBm) 2.5mW (4dBm) 1mW (0dBm) 1mW (0dB) 0.25mW (-6dBm) N/A -4db/time Max twice Optional Optional Power 1mW (class 3) 3% power of cellular phone 10meters of transmission distance or 100m by PA Power 100mW(class 1) 100 meters of transmission distance 42

22 Frequency Hopping 78 Frequency 0 Time 43 FHSS Data Source d(t) Digital Modulator + Transmitter Hopping Code Generator Frequency synthesizer Receiver Front-end Filter + Data Detector ^ d(t) Local hopping code generator Frequency synthesizer 44

23 Modulation and Symbol Rate Symbol Rate : 1M symbols/sec (1MHz) GFSK (Gaussian Frequency Shift Keying) Binary One (1) : Positive frequency deviation Binary Zero (0) : Negative frequency deviation Maximum frequency deviation Between 140kHz and 175kHz Magnitude fo- f fo fo+ f frequency 45 Network Topology Radio Designation Connected radios can be master or slave Radios are symmetric (same radio can be master or slave) Piconet Master can connect to 7 simultaneous or 200+ active slaves per piconet Each piconet has maximum capacity (1 Msps and 1 Mbps) Unique hopping pattern/id Scatternet High capacity system Minimal impact with up to 10 piconets within range Radios can share piconets! 46

24 Piconet vs. Scatternet A scatternet contains two piconets 47 Piconet and Scatternet point-to-point (piconet) multi-point (piconet) Master host Slave host scatternet 48

25 Basic Baseband Protocol Frame (1.25 ms) f k f k+1 Frame f k f k+1 Master One Slot Packet Master Three Slot Packet Slave One Slot Packet Slave One Slot Packet 625 us One Slot 625 us One Slot Spread spectrum frequency hopping radio Hops every packet Packets are 1, 3 or 5 slots long Frame consists of two packets Transmit followed by receive Nominally hops at 1600 times a second (1 slot packets) 49 Time Division Duplex (TDD) Master : even numbered slots Slave : odd numbered slots The Slot Number ranges from Master f(2k) f(2k+1) f(2k+2) +/-10 µs 220 µs Slave even (625µs) guard time Packet odd (625µs) even time slot Access code/header Payload guard time for hopping 50

26 Multi-slot Packets Different packet overhead will result in different throughput DH1 : 172.8Kbps in Sym. and Asyn. modes DH3 : 390.4Kbps in Sym. mode; and 54.4Kbps in Asyn. Mode DH5 : 433.9Kbps in Sym. mode; 721 and 57.6Kbps in Aysn. DH : without FEC 1-slot Packet (DH1) 3-slot Packet (DH3) 5-slot Packet (DH5) f(2k) f(2k+1) f(2k+2) f(2k+3) f(2k+4) f(2k) f(2k+1) f(2k+2) f(2k+3) f(2k+4) f(2k) f(2k+1) f(2k+2) f(2k+3) f(2k+4) even (625µs) odd (625µs) even (625µs) odd (625µs) 51 ZigBEE IEEE Low Rate WPAN (LR-WPAN) Simple Low cost Low power consumption E.g. Sensor networks Data rates: kbps 52

27 IEEE Protocol stack 53 IEEE DEVs 2 or more DEVs form a PAN 2 different types of DEVs Full functional Device (FFD) Coordinator and simple node Any topology Talks to any device Reduced Functional Device (RFD) Simple node only, either source or desination Star topology only Talks to network coordinator only 54

28 IEEE Star 55 IEEE Peer-to-Peer 56

29 IEEE Combined 57 Comparison between WPAN 58

30 ZigBee network applications monitors sensors automation control INDUSTRIAL & COMMERCIAL CONSUMER ELECTRONIC S TV VCR DVD/CD Remote control monitors diagnostics sensors PERSONAL HEALTH CARE ZigBee LOW DATA-RATE RADIO DEVICES PC & PERIPHERAL S mouse keyboard joystick consoles portables educational TOYS & GAMES HOME AUTOMATION security HVAC lighting closures 59 Wireless technologies Range Meters 10,000 GSM GPRS EDGE 3G , ZigBee b a/g Bluetooth 2.0 Hiper LAN/2 Bluetooth Bluetooth 1.5 WiMedia Bandwidth 10 kbps ,000 10, ,000 60

31 ZigBee/ architecture ZigBee Alliance 45+ companies: semiconductor mfrs, IP providers, OEMs, etc. Defining upper layers of protocol stack: from network to application, including application profiles First profiles published mid 2003 IEEE Working Group Defining lower layers of protocol stack: MAC and PHY 61 ZigBee related to IEEE ZigBee takes full advantage of a powerful physical radio specified by IEEE ZigBee adds logical network, security and application software ZigBee continues to work closely with the IEEE to ensure an integrated and complete solution for the market 62