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November 5, 2004 ©KP University of Massachusetts

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  • 1. University of Massachusetts CWINS Evolution of Wireless Network K. Pahlavan November 5, 2004 ©KP
  • 2. Outline  Introduction  Voice-Oriented Cellular Networks – 1G analog cellular – 2G • Cellular, PCS, Mobile data, WLAN – 3G and beyond • IMT-2000 • Broadband and adhoc networks • Future directions and 4G systems  Wireless Data Networks – Mobile data – Broadband Adhoc networks 2
  • 3. What is a wireless network? 3
  • 4. Evolution of terminals Morse Pad Workstation Telephone Mainframe Printer Computer Fax iBook Hand held computer Scanner Video Mouse Pen computer Cell phone PDA Laptop CRT projector Keyboard 4
  • 5. 5 Bandwidth (Kbps) (100 Mbps) (10 Mbps) (1 Mbps) 10,000 100,000 100 10 1,000 1 Smart Appliances Utility Metering Security Systems Phone Appliances Real Audio G2 MP3 Audio Games Printing Internet Camcorder DV MPEG2 Video 3D Games Bandwidth Requirements for Applications
  • 6. Four Original Traditional Industries 6
  • 7. 1G Systems  Analog cellular or mobile phone for the car  Analog cordless telephones for homes  Pagers (?) as mobile data  Low-speed LANs using voiceband modems and walkie-talkies as local wireless (?) 7
  • 8. 1G Analog Cellular Systems Standar Forward Reverse Channel Region Comments d Band MHz Band MHz Spacing kHz AMPS 824-849 869-894 30 America Also in Australia, SE Asia, Africa TACS 890-915 935-960 25 EC Later, bands were allocated to GSM ETACS 872-905 917-950 25 UK NMT 450 453-457.5 463-467.5 25 EC NMT 900 890-915 935-960 12.5 EC Freq. overlapping Also in Africa and SE Asia C-450 450-455.74 460-465.74 10 Germany Portugal RTMS 450-455 460-465 25 Italy Radioco 192.5-199.5 200.5-207.5 12.5 France m 2000 215.5-233.5 207.5-215.5 165.2-168.4 169.8-173 414.8-418 424.8-428 NTT 925-940 870-885 25/6.25 Japan First band is 915-918.5 860-863.5 6.25 nationwide, 922-925 867-870 6.25 others regional JTACS/N 915-925 860-870 25/12.5 Japan All are regional TACS 898-901 843-846 25/12.5 918.5-922 863.5-867 12.5 8
  • 9. 2G Systems  Digital cellular for mobile users  PCS for pedestrians  Independent Mobile data for portable computers  WLANs for wire replacement 9
  • 10. 2G Digital Cellular Systems System GSM IS-54 JDC IS-95 Region Europe/Asia USA Japan USA/Asia Access Method TDMA/FDD TDMA/FDD TDMA/FDD CDMA Modulation Scheme GMSK /4-DQPSK /4-DQPSK QPSK Frequency Band 935-960 869-894 810-826 869-894 (MHz) 890-915 824-849 940-956 824-849 1477-1489 1429-1441 1501-1513 1453-1465 Carrier Spacing (kHz) 200 30 25 1250 Bearer 8 3 3 Variable channels/carrier Channel bit rate 270.833 48.6 42 1228.8 (kbps) Speech Coding 13 kbps 8 kbps 1-8 kbps (variable) Average handset Tx. 125 mW 20 mW 20 mW Power (mW) Peak power (W) 1 0.6 Frame duration (ms) 4.615 40 20 20 10
  • 11. 2G Digital Cordless (PCS) CT2 and System CT2+ DECT PHS PACS Europe Region Canada Europe Japan United States Access Method TDMA/TDD TDMA/T DD TDMA/TDD TDMA/FDD 864 -868 1850 -1910 Frequency band (MHz) 944 -948 1880 -1900 1895 -1918 1930 -1990 Carrier spacing (KHz) 100 1728 300 300, 300 Number of carriers 40 10 77 16 pairs Bearer channels/carrier 1 12 4 8 per pair Channel bit rate (kb/s) 72 115 2 384 384 Modulation GFSK GFSK /4-DQPSK /4-DQPSK Speech coding 32 kb/s 32kb/s 32 kb/s 32 kb/s Ave. handset Tx power (mW) 5 10 10 25 Peak handset Tx power (mW) 10 250 80 200 Frame duration (ms) 2 10 5 2.5 11
  • 12. Mobile Data Systems (2G, 2.5G?) System ARDIS Mobitex CDPD TETRA GPRS Metricom Frequency 800 935-940 869- 380- 890-915 902-928 band bands 896-961 894 383 935-960 ISM (MHz) 45 kHz 824- 390- bands sep 849 393 Channel bit 19.2 8.0 19.2 36 300-400 100 rate (kbps) RF channel 25KHz 12.5KHz 30KHz 25KHz 200 KHz 160KHz spacing Channel FDMA/ FDMA/ FDMA/ FDMA/ FDMA/ FHSS/ Access/ DSMA Dynamic DSMA DSMA TDMA/ BTMA Multi-user S-ALOHA Reserve access Modulation 4-FSK GMSK GMSK /4- GMSK GMSK Technique DQPS K HDR that can support up to over 2Mbps 12
  • 13. WLAN Standards (2G,3G,4G?) Parameters IEEE 802.11 IEEE IEEE 802.11a HIPERLAN/2 HIPERLAN/1 802.11b Status Approved, Final Final ballot, In preparation Approved, Products ballot, Products No products Products Freq. Band 2.4 GHz 2.4 GHz 5 GHz 5 GHz PHY, DSSS: DSSS: OFDM GMSK modulation FHSS: CCK Data rate 1, 2 Mbps 1, 2, 6, 9, 12, 18, 24, 36, 54 Mbps 23.5 Mbps 5.5, 11 Mbps Access Distributed control, Central control. Active method CSMA/CA Reservation contention Or based access resolution, RTS/CTS Priority signalling Also 802.11g that is OFDM in 2.4GHz coexisting with 11.b. 13
  • 14. 3G W-CDMA for IMT-2000  CDMA provides a better quality of voice  CDMA is more flexible air interface to customize multi-media applications  Two overall approaches – build on the success of the installed GSM infrastructure (UMTS/IMT-2000) – build on the cdmaOne experience (cdma2000/IMT-2000) 14
  • 15. Overview of the Current Wireless Access Methods Wide Area Network (WAN) Mobility - Expensive licensed bands Vehicle Local Area Network (LAN) Outdoor Walk - High speed unlicensed 3G Personal Area Network (PAN) Fixed Cellular -Ad-hoc unlicensed Walk W-LAN Indoor Fixed/ WPAN Desktop 0,1 1 10 100 Mbps User Bitrate, Datacom services 15
  • 16. Two Sectors of Wireless Industry:  Voice-Oriented Cellular – 3G IMT-2000 for Access – Integrates Cellular, PCS, and Mobile Data – Operates in licensed bands  Data-Oriented Broadband Ad-hoc – WLAN and WPAN – Provides for broadband wireless Internet access and wireless media for consumer products – in unlicensed bands for traditional 16
  • 17. Beyond 3G  First Generation: Analog Cellular, Analog Cordless, Pager (?), Local Area Low-Speed Packet Data  Second Generation: Digital Cellular, PCS, Mobile Data, Wireless LAN  Third Generation: Improved Quality and Capacity for the Voice and Higher Data Rates for the Data.  Beyond 3G: – Integration with WLAN in unlicensed bands – Increase the quality and capacity using time-space diversity – Include location aware services – Include ad-hoc networking capabilities 17
  • 18. Braodband and Ad-Hoc Access:  Wireless LAN for broadband access – IEEE 802.11 – HIPERLAN  Wireless PAN for ad-hoc networking – Bluetooth – UWB 18
  • 19. Evolution of WLAN Products: Building Cross-connect (2) PCMCIA cards and Laptops Wired Backbone (3) (1) Shoebox type LAN Extension 19
  • 20. W-CAN ATWATER KENT LABORATORIES Fuller Laboratories Wireless Wireless Bridge Bridge Wireless A ccess Point Sw itch Router Electronic w hiteboard Campus Backbone Netw ork Gordon Library Wireless Bridge Bridge Bridge Wireless Wireless Wireless Bridge Olin Hall Salisbury Laboratories Wireless Wireless Bridge Bridge 20
  • 21. Telecomm. View  Corporate Network Home 3rd generation Cellular  Home Environment Internet Office Ethernet ISP  Public Networks 21
  • 22. BW-Internet Access 22
  • 23. WPAN Vision for Bluetooth Landline Cable Replacement Data/Voice Access Points Personal Ad-hoc Networks 23
  • 24. Two Technologies for Home Internet Broadband Home-Access Broadband Home-Distribution 24
  • 25. Military interest ……….. 25
  • 26. Body LAN or Wearable LAN 26
  • 27. Urban fighting ……….. 27
  • 28. Self healing mines …. 28
  • 29. Unmanned combat air vehicle… 29
  • 30. Fixed-mobile networks 30
  • 31. Wireless vs Wired  Wireless operates on the unreliable radio channel that needs far more complex PHY layer as well as connection management  Wireless should arrange change of connection point during the moves by a more complex registration and call routing  Wireless has limited number of channels (radio frequency bands) that should be managed to be shared among a huge number of users  Wireless needs security (authenticate and ciphering) to avoid fraud and preserve privacy  Wireless, due to bandwidth scarcity, needs more complex source coding techniques (e.g. for voice or video)  Wireless needs permanent and temporary addressing to support mobility  Wireless mobile operates out of the battery energy and needs power management  Wireless terminals use small screens that needs special graphics 31
  • 32. Elements of a Wireless Network Architecture  Services – voice, data, call forwarding, …  System infrastructure to connect the mobile user to the existing fixed networks – Mobile terminal – Fixed wireless infrastructure  Detailed layered protocols to tie all components together – PHY, Data Link, Network Layer  Traffic engineering and deployment 32
  • 33. Technical Aspects of Wireless Infrastructure  Network deployment planning  Mobility and location management  Radio resource and power management  Security 33
  • 34. Technical Aspects for Air-Interface  Understanding of the medium (path-loss, variations of the channel and multipath effects)  Study of the PHY layer alternatives (pulse transmission techniques, traditional RF, spread spectrum)  Study of the MAC layer alternatives (voice- oriented FDMA, TDMA and CDMA, and data- oriented: ALOHA and CSMA based) 34
  • 35. What is important in wireless?  In voice oriented networks – 2G designed a new digital air-interface to facilitate data applications and increase the capacity of analog 1G – 3G designed a CDMA air-interface to provide higher data rates and improve the quality and capacity – 4G possibly uses time-space diversity and MIMO air-interface to get what 3G did not  In data oriented networks – 802.11 used spread spectrum modem because FCC wanted it. – CCK modems were developed for 802.11b to increase the data rate at 2.4GHz – OFDM was used in 802.11a and g to further increase the data rate – UWB is expected to increase the data rate and number of users 35
  • 36. What is a telecomm network ? Satellite Satellite dish Satellite dish Point-to-point plus interconnect elements (switches/routers) 36
  • 37. Wireless Voice-Oriented Networks Traditional fixed telephone infrastructure Additional fixed components for a wireless infrastructure 37
  • 38. Comparison of PCS and Cellular System Aspects PCS Cellular Cell size 5-500 m 0.5-30 Km Coverage Zonal Comprehensive Antenna height < 15 m > 15 m Vehicle speed < 5 kph < 200 kmp Handset comp. Low Moderate Base station comp. Low High Spectrum access Shared Exclusive Average handset power 5-10 mW 100-600 mW Speech coding 32 kb/s ADPCM 7-13 kb/s vocoder Multipath mitigation Antenna diversity Diversity/equalizati (optional) on/Rake Duplexing Usually TDD FDD Detection Non-coherent Coherent 38