2g 3g

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2g 3g

  1. 1. Wireless Communication Engineering UNIT 1 PART 2
  2. 2. Wireless <ul><li>Billions of wireless devices are in use </li></ul><ul><li>4 wireless technologies in 10 communication technologies with most market potential: </li></ul><ul><ul><li>Wi-Fi </li></ul></ul><ul><ul><li>UWB </li></ul></ul><ul><ul><li>Software Radio </li></ul></ul><ul><ul><li>Wireless Mesh </li></ul></ul><ul><ul><li>Other six are: Nanotech, PON, Soft Switching, MPLS, FSO, Optical Switching </li></ul></ul>
  3. 4. EM Spectrum for Telecom <ul><li>Most spectra licensed; 3G license is very expensive; FCC is a mighty sector </li></ul><ul><li>Infrared, ISM band, and amateur radio band are license-free </li></ul><ul><li>HW2: Find out what spectrum is used for GSM, IS-95, 802.11b WLAN. What data rates are available in each system? What transmission characteristics makes these spectrum bands suitable for wireless communications? </li></ul>
  4. 5. APPLICATIONS <ul><li>1G – analog signals only ( ph call) </li></ul><ul><li>2G – sms </li></ul><ul><li>2.5G – mms, www ,email access (WAP) </li></ul><ul><li>2.75 – High data rate </li></ul><ul><li>3G – mobile internet, mobile tv, video calling </li></ul><ul><li>3.5G – mobile broad bands, smart ph, mobile modems </li></ul><ul><li>4G – IP telephony, ultra broadband modems </li></ul>
  5. 6. Evolution of Wireless Sys. (1G) <ul><li>Handoff was not solved until the development of microprocessor, efficient remote-controlled RF synthesizer, and switching center. </li></ul><ul><li>1G Cellular System </li></ul><ul><ul><li>Designed in 1970s, deployed in early 1980s </li></ul></ul><ul><ul><li>Analog, 42 control channels, 790 voice channels </li></ul></ul><ul><ul><li>Handoff performed at BS based on received power </li></ul></ul><ul><ul><li>AMPS in US; TACS in part of Europe; NTT in Japan; C450 in West German, and NMT in some countries. </li></ul></ul><ul><ul><li>Became highly popular; AMPS still popular in US! </li></ul></ul>
  6. 7. Evolution of Wireless Sys. (2G) <ul><li>2G Systems </li></ul><ul><ul><li>Digital cellular telephony </li></ul></ul><ul><ul><li>Modest data support, incompatible </li></ul></ul><ul><ul><li>GSM: a common TDMA technology for Europe; claim about 3/4 of subscribers worldwide. </li></ul></ul><ul><ul><li>IS-54 and IS-136: TDMA technology in US; compatible with AMPS; </li></ul></ul><ul><ul><li>IS-95: CDMA; standardized in 1993; South Korea and Hong Kong deployed it in 1995; US in 1996. </li></ul></ul>
  7. 8. Evolution of Wireless Sys. (2.5G) <ul><li>2G telephony is highly successful </li></ul><ul><li>Enhancement to 2G on data service </li></ul><ul><ul><li>GSM: HSCSD and GPRS </li></ul></ul><ul><ul><li>IS-95: IS-95b </li></ul></ul><ul><ul><li>IS-136: D-AMPS+ and CDPD </li></ul></ul><ul><li>The improved data rate is still too low to support multimedia traffic </li></ul><ul><li>ITU initiated 3G standardization effort in 1992, and the outcome is IMT-2000. </li></ul>
  8. 9. Evolution of Wireless Sys. (3G) <ul><li>IMT-2000 comprises several 3G standards: </li></ul><ul><li>EDGE, data rate up to 473Kbps, backward compatible with GSM/IS-136 </li></ul><ul><li>cdma2000 (Qualcomm), data rate up to 2Mbps, backward compatible with IS-95 </li></ul><ul><li>WCDMA (Europe), introduces a new 5MHz channel structure; data rate up to 2Mbps; </li></ul><ul><li>TD-SCDMA (China), CDMA in TDD fashion </li></ul>
  9. 10. Evolution of Wireless Sys. (4G) <ul><li>Problems of 3G systems </li></ul><ul><ul><li>Immature 3G license auction increases the financial burden </li></ul></ul><ul><ul><li>What are the killer applications of 3G? </li></ul></ul><ul><ul><li>No unified standard (political factors dominate) </li></ul></ul><ul><li>4G systems </li></ul><ul><ul><li>Research initiated, but still not well-defined </li></ul></ul><ul><ul><li>Data-oriented, seamless integrated with wireline </li></ul></ul><ul><ul><li>Indoor data rate up to 100 Mbps, outdoor data rate up to 20Mbps. </li></ul></ul>
  10. 11. Evolution of Mobile Radio Communications
  11. 12. Paradigm From 1G to Beyond 3G First Generation <ul><li>Analogue </li></ul><ul><li>Circuit switched </li></ul><ul><li>Basic voice telephony </li></ul><ul><li>Low capacity </li></ul><ul><li>Limited local and regional coverage </li></ul>Second Generation <ul><li>Digital </li></ul><ul><li>Circuit switched </li></ul><ul><li>Voice plus basic data applications </li></ul><ul><li>Low data speed </li></ul><ul><li>Enhancements towards </li></ul><ul><ul><li>packet switching </li></ul></ul><ul><ul><li>higher data rates </li></ul></ul><ul><li>Trans-national and global roaming </li></ul><ul><li>Digital </li></ul><ul><li>Packet and circuit switched </li></ul><ul><li>Advanced data (multimedia ) applications </li></ul><ul><li>Fast data access </li></ul><ul><li>Global coverage </li></ul><ul><li>Global roaming </li></ul>Third Generation Beyond Third Generation <ul><li>Digital </li></ul><ul><li>Packet switched </li></ul><ul><li>All IP based (IPv6 ) </li></ul><ul><li>More advanced multimedia applications </li></ul><ul><li>User in control </li></ul><ul><li>Flexible platform of complementary access systems </li></ul><ul><li>High speed data </li></ul><ul><li>Improved QoS </li></ul><ul><li>Global coverage </li></ul><ul><li>Global roaming </li></ul>
  12. 13. Mobility and Information Speed of Evolving Mobile Communication Systems
  13. 14. Trends in Wireless Commun. <ul><li>Personal Communications (Goal of mobile communications) </li></ul><ul><li>All IP based (IPv6) (Packet switched) </li></ul><ul><li>Flexible platform of complementary access systems( Combination of different wireless access systems , Hot spot services will be introduced by high-speed wireless access (>100mbps)) </li></ul><ul><li>Higher system capacity (Users/Service, 5-10 times higher than 3G) </li></ul><ul><li>Higher Transmission Data rate </li></ul><ul><li>Higher frequency efficiency </li></ul><ul><li>More advanced multimedia applications </li></ul><ul><li>Improved QoS </li></ul><ul><li>Realize high levels of security and authentication </li></ul><ul><li>Global coverage </li></ul><ul><li>Global roaming </li></ul>
  14. 15. All IP Based
  15. 16. All IP based IP/ATM/MPLS Backbone Mobile Internet Application Platforms Mobile Internet Application Servers Media Gateway Mobility, Connection & Control Servers Mobility Gateway Intelligent Edge Broadband Gateway IP Multi Radio OWLAN Broadband Accesses Network Domain Service Domain Internet PSTN ISDN
  16. 17. Combination of different wireless access systems IEEE.802.11 WLAN WPAN WLAN WWAN PAN Bluetooth PDMA
  17. 18. Network of 3G beyond Services and applications IP based core network Media access system IMT-2000 UMTS WLAN type cellular GSM short range connectivity Wireline xDSL other entities DAB DVB return channel: e.g. GSM download channel New radio interface
  18. 19. Transmission Data Rate <ul><li>Highest data rate(3G) </li></ul><ul><ul><li>at least 144 Kb/s in a vehicular environment, </li></ul></ul><ul><ul><li>384 Kb/s in a pedestrian environment, </li></ul></ul><ul><ul><li>2048 Kb/s in an indoor office environment. </li></ul></ul><ul><li>Highest data rate (4G) </li></ul><ul><ul><li>2Mbps in a vehicular environment,, 20Mbps in a pedestrian environment </li></ul></ul><ul><ul><li>Wide Area, high velocity : 100Mbps </li></ul></ul><ul><ul><li>Indoor, lower velocity : 1Gbps </li></ul></ul><ul><li>Evolution of transmission data rate </li></ul>2G 3G and beyond 9.6-14.4 kbps evolved 2G 64-144 kbps 384 kbps-2 Mbps 100 Mbps? 384 kbps-20 Mbps
  19. 20. System Capacity and spectrum efficiency Capacity: 5-10 times higher than 3G Frequency efficiency: Multi-cell: > 2bits/Hz Single-cell: 5~10 bits/Hz
  20. 21. Drivers of 3G Beyond <ul><li>3G evolution … but difficult </li></ul><ul><ul><li>to extend to higher data rate with CDMA only technology; </li></ul></ul><ul><ul><li>to provide various services with different QoS </li></ul></ul><ul><ul><li>to have enough frequency resource to accommodate more subscribers </li></ul></ul><ul><li>Drawback </li></ul><ul><ul><li>Low system capacity </li></ul></ul><ul><ul><li>Low spectrum efficiency </li></ul></ul>0 25 1998 1999 2000 2001 50 75 100 125 150 Pbit/day Real Time (e.g. Voice) Non Real Time (e.g. Internet access) Mobile Internet User Mobile User 0 200 400 600 800 1000 1200 1400 1600 1800 1995 2000 2005 2010 Subscriptions (millions) Mobile Fixed Mobile Internet Fixed Internet
  21. 22. Drivers of 3G Beyond 3G 2G Evolution from 2G systems and Beyond Revolution from subscriber service expectations IP Revolution from IP infrastructure
  22. 23. Service Forecast for Asia Region 0 5 10 15 20 25 1999 (Forecast by ITU-R TG-8/1 for Asia) 2015 (Extrapolation) Up Down Up Down Up Down 63% 23? 5.4 1 19.8 10 %  30%  15%  28%  8% 3.4 0.5 0.5 91 % Multimedia  (U:128k,D:10Mbps)  (U:128k, D:2Mbps)  (U:64k,D:384kbps)  (U/D:128kbps×n) 1G/2G services Voice (U/D: 16k, VOX0.5) Others (<64 kbps) 9 %  Multimedia traffic increases 40%/year .  10Mbps downstream service emerges.  Saturation of 1G/2G services traffic. Subscribers ×1.5 Voice : Multimedia traffic ratio  1 : 2 (in 2010) 3.9 1.5 Relative traffic value in bits (Ref: 1999) Year 2010
  23. 24. Multimedia Services <ul><ul><ul><li>Internet access </li></ul></ul></ul><ul><ul><ul><li>Shopping/banking(e-commerce) </li></ul></ul></ul><ul><ul><ul><li>Video conferencing </li></ul></ul></ul><ul><ul><ul><li>Video on demand </li></ul></ul></ul><ul><ul><ul><li>Telemedicine </li></ul></ul></ul><ul><ul><ul><li>Distance learning </li></ul></ul></ul>
  24. 25. Challenges <ul><li>Unreliable Channels (Cross Layer Design) </li></ul><ul><li>Scarce Spectrum and Resource Management </li></ul><ul><li>Stringent Power Budget </li></ul><ul><li>Security </li></ul><ul><li>Location and Routing </li></ul><ul><li>Interfacing with Wired Networks </li></ul><ul><li>Health Concern </li></ul><ul><li>Diversified Standards and Political Struggle </li></ul>

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