"Evolving Technologies for Terrestrial Wireless"


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"Evolving Technologies for Terrestrial Wireless"

  1. 1. Evolving Technologies for Terrestrial Wireless BAD 64046 26 February 2003 Cellular Subscriber Growth Worldwide
  2. 2. Emerging 2.5G Cellular Data Transmission <ul><li>Video and other rich content requires higher data rates </li></ul><ul><li>Unwilling to wait for 3G (third generation) data rates, some interim technologies are proposed by the industry </li></ul><ul><li>These extend present 2G cellular standards, so are called “2.5G.” </li></ul>
  3. 3. CDMA Standards <ul><li>Standards for passing data on existing cellular wireless circuits </li></ul><ul><li>IS-95B attains 64 Kbps by replacing voice channel overhead with a digital packet system </li></ul><ul><li>IS-95B is not an overlay standard (as was CDPD, which uses free AMPS bandwidth) </li></ul><ul><li>IS-95C is coming out now, supporting 144 Kbps for mobile computing </li></ul><ul><li>All above are moving toward the cdma2000 3G standard </li></ul>
  4. 4. High Speed Circuit-Switched Data <ul><li>HSCSD provides circuit-switched data transmission using multiple time slots on a GSM network </li></ul><ul><li>14.4 Kbps/slot </li></ul><ul><li>Nokia (1998) has a four slot 57.6 Kbps system </li></ul><ul><li>Works best with asymmetric application demands </li></ul><ul><li>Major advantage of HSCSD: requires no hardware changes -- just a base station software adaptation </li></ul><ul><li>See: http://www.ericsson.com/wireless/products/mobsys/gsm/subpages/wise/hscsd.shtml </li></ul>
  5. 5. GPRS Synopsis <ul><li>GPRS facilitates instant connections whereby information can be sent or received immediately as the need arises. No dial-up modem connection is necessary. This is why GPRS users are sometimes referred to be as being &quot;always connected&quot;. Immediacy is one of the advantages of GPRS (and SMS) when compared to Circuit Switched Data. High immediacy is a very important feature for time critical applications such as remote credit card authorization where it would be unacceptable to keep the customer waiting for even thirty extra seconds. </li></ul><ul><li>Source: http://www.mobileGPRS.com/gprs.asp?link=1 </li></ul>
  6. 6. General Packet Radio Service <ul><li>GPRS provides packet based applications and services </li></ul><ul><li>Uses multiple time slots of the GSM radio channel </li></ul><ul><li>Raw rate of 24 Kbps/slot </li></ul><ul><li>Phase 1: Multislot half duplex </li></ul><ul><ul><li>Max data rate of 4 x 14.4 Kbps </li></ul></ul><ul><li>Phase 2: Multislot full duplex </li></ul><ul><ul><li>All eight slots together give 115.2 Kbps </li></ul></ul>
  7. 7. HSCSD vs. GPRS <ul><li>HSCSD is an inefficient user of bandwidth because it marries one each slot to one and only one user </li></ul><ul><li>GPRS mixes user data streams within a slot </li></ul><ul><li>GPRS is directly compatible with TCP/IP because both are packet-switched </li></ul><ul><li>HSCSD fits better with the installed PSTN base </li></ul><ul><li>GPRS and HSCSD can coexist at the 2.5G level </li></ul><ul><li>Presently, GPRS “phones” can only utilize four of the eight slots because of transmitter heating </li></ul>
  8. 8. EDGE <ul><li>“ Enhanced Data Rates for Global Evolution” </li></ul><ul><ul><li>Initiated by Ericsson </li></ul></ul><ul><li>Up to 384 Kbps mobile wide area coverage </li></ul><ul><li>Uses advanced 8PSK modulation </li></ul><ul><ul><li>3 bits sent per each transmitted symbol </li></ul></ul><ul><li>Same channel bandwidth and carrier structure as GSM, and uses GPRS infrastructure </li></ul><ul><li>Commercial service possibly available in 2001 </li></ul>
  9. 9. Why Edge? <ul><li>The expected traffic increase due to Mobile Internet will put enormous demands on capacity in mobile networks. </li></ul><ul><li>It is expected that in most mature markets, there will be a need for both enhanced 2G networks as well as 3G networks to cope with capacity demands. </li></ul><ul><li>A major step in the evolution of General Packet Radio Service (GPRS), for instance, will be implementing EDGE, which will deliver speeds at 384 kbit/s and more. </li></ul>
  10. 10. 3G Technologies <ul><li>Initially 1985 ITU Future Public Land Mobile Telecommunications System </li></ul><ul><li>Has evolved into “International Mobile Telecommunications-2000” (IMT-2000) </li></ul><ul><li>ITU has allocated 1885 - 2025 MHz and 2110 - 2200 MHz </li></ul>
  11. 11. Goals of IMT-2000 <ul><li>Increased efficiency and capacity </li></ul><ul><li>New services available such as PC WANs </li></ul><ul><li>Bandwidth on demand </li></ul><ul><li>Increased flexibility, especially backwards compatibility </li></ul><ul><li>Seamless roaming across dissimilar networks </li></ul><ul><li>Integration of satellite services and fixed wireless with the cellular network </li></ul><ul><li>384 Kbps mobile, 2M fixed, 20 M fixed in later stage </li></ul>
  12. 12. Moving Toward IMT-2000 <ul><li>15 proposals submitted in 1998 </li></ul><ul><li>Proposal unification process underway currently </li></ul><ul><li>Main contenders are: W-CDMA and cdma2000 </li></ul><ul><li>W-CDMA </li></ul><ul><ul><li>Wireless Code Division Multiple Access </li></ul></ul><ul><ul><li>Backed by Japanese and European groups </li></ul></ul><ul><ul><li>Backward compatible into GSM </li></ul></ul>
  13. 13. <ul><li>cdma2000 </li></ul><ul><ul><li>Backed by U/S. and Korea </li></ul></ul><ul><ul><li>Will require minimal hardware retrofit, at least initially </li></ul></ul><ul><li>First W-CDMA system in place in Japan by NTT Mobile Communications Network now </li></ul><ul><li>Both W-CDMA and cdma2000 use orthogonal complex quadrature phase shift keying modulation and identical error correction schemes </li></ul><ul><li>ITU has endorsed both standards, so global travelers will need dual-mode handsets </li></ul>Moving Toward IMT-2000 (2)
  14. 14. Wireless Local Loop <ul><li>Goal is to replace the wire-based local loop </li></ul><ul><li>Fixed WLL has four potential uses </li></ul><ul><ul><li>1. Bring telephony to underserved parts of the world </li></ul></ul><ul><ul><li>2. Provide advanced services to businesses </li></ul></ul><ul><ul><li>3. Replace wireline services within office and residential areas </li></ul></ul><ul><ul><li>4. Competing alternative to copper local loops in liberalized markets </li></ul></ul>
  15. 15. WLL Growth Projections WLL Growth Projections Source:http://www.iec.org/tutorials/wll/topic01.html?Next.x=49&Next.y=16
  16. 16. Where Is WLL Big? <ul><li>Extensive deployment in Asia, Eastern Europe, and other countries without adequate wireline services </li></ul><ul><li>Offer rapid deployment, configuration, and adaptation </li></ul><ul><li>Terrain-flexible </li></ul><ul><li>Example: 15% of all new customers in Poland are served by WLL technology </li></ul>
  17. 17. WLL: Also Cordless Systems <ul><li>“ WLL” is sometimes also used to refer to cordless and low power mobile systems </li></ul><ul><li>Dual use handsets can act as cordless telephone and revert to a public wireless network when out of range of the home base station </li></ul><ul><li>Infrastructure costs very low compared to cellular </li></ul>
  18. 18. Cordless System Realizations <ul><li>PACS (Personal Access Communications System) (U.S.) </li></ul><ul><li>PWT (Personal Wireless Telecommunications) (U.S.) </li></ul><ul><li>DECT (Digital Enhanced Cordless Telephone) (Europe) </li></ul><ul><li>CT2 (Cordless Telephony Generation 2) (Singapore, Hong Kong, Canada, Europe) </li></ul><ul><li>PHS (Personal Handyphone System (Japan) </li></ul>
  19. 19. Radio Frequency Wireless Local Loop <ul><li>Project Angel </li></ul><ul><ul><li>1997 AT&T trial </li></ul></ul><ul><ul><li>Uses neighborhood antenna mounted on a utility pole </li></ul></ul><ul><ul><li>Method for AT&T to offer local phone service while avoiding local phone charges </li></ul></ul><ul><ul><li>Especially valuable in areas where AT&T does not own a cable TV company </li></ul></ul><ul><ul><li>One antenna serves 2000 homes; subscribers need an 18 inch dish </li></ul></ul><ul><ul><li>See http://news.cnet.com/news/0-1004-200-1581606.html </li></ul></ul>
  20. 20. Project Angel (cont.) <ul><li>Each household will have up to four phone lines and 512 Kbps Internet </li></ul><ul><li>1999 cost of deployment is about $1500/home </li></ul><ul><li>Year 2000 trial in Dallas and Ft. Worth involving 1.5 million homes </li></ul><ul><li>Partial rollout 22 March 2000 </li></ul><ul><li>Full scale rollout in 2001 </li></ul>
  21. 21. WLL Equipment <ul><li>Qualcomm and Hitachi joint development agreement to achieve 2.4 Mbps data rate </li></ul><ul><li>Qualcomm High Data Rate (HDR) technology to work within existing CDMA 1.25 MHz cellular networks </li></ul><ul><li>Reserves part of the cellular spectrum for data </li></ul><ul><li>Hitachi will build the hardware </li></ul><ul><li>2001 rollout targeted at neighborhoods where ADSL is unavailable </li></ul>
  22. 22. WLL for Business Customers <ul><li>Teligent point to point microwave system </li></ul><ul><li>44.376 Mbps possible, but most real systems run at 1.5 Mbps (T1 speed) </li></ul><ul><li>12 inch dishes on business roofs link to local base station that interfaces to the PSTN </li></ul><ul><li>Less costly than T1 line charges </li></ul><ul><li>AT&T owns 40% of Teligent </li></ul>
  23. 23. Nonradio Local Loop <ul><li>Relies on lasers </li></ul><ul><li>Susceptible to atmospheric conditions </li></ul><ul><li>Lucent: Wavestar OpticAir OLS System </li></ul><ul><ul><li>2.5 Gbps data rate, up to 2 km </li></ul></ul><ul><ul><li>Expecting 20 Gbps over 2 km </li></ul></ul><ul><ul><li>See http://www.idg.net/crd_lucent_78408.html </li></ul></ul><ul><li>Terabeam Networks (Seattle) </li></ul><ul><ul><li>1 Gbps </li></ul></ul><ul><ul><li>Directors work through office windows </li></ul></ul><ul><ul><li>Service rollout over the next three years </li></ul></ul>
  24. 24. Terabeam Technology Source: http://www.terabeam.com/pro/pro_pro_int.shtml
  25. 25. Private Data Networks <ul><li>These are wide area, usually for specialized applications </li></ul><ul><li>Do not provide voice </li></ul><ul><li>Coverage areas are typically not divided geographically -- a major departure from cellular </li></ul>
  26. 26. Mobiltex <ul><li>Ericcson introduction in Sweden in 1984 </li></ul><ul><li>Usage has spread to many countries, including the U.S. </li></ul><ul><li>Managed by Mobiltex Operators Association </li></ul><ul><li>Packet-switched network with max length of 512 bytes; packets are sent independently </li></ul><ul><li>Each user has a unique access number </li></ul><ul><li>Messages for a device are routed downward through the hierarchy </li></ul><ul><li>BellSouth Mobile Data is largest U.S. -- focuses on e-mail and two-way pagers </li></ul>
  27. 27. ARDIS <ul><li>Advanced Radio Data information Service </li></ul><ul><li>Developed for IBM and Motorola use by their field organizations </li></ul><ul><li>Offered commercially in 1990 </li></ul><ul><li>Data only; 4.8 Kbps or 19.2 Kbps </li></ul><ul><li>Covers 430 metropolitan areas </li></ul><ul><li>Now switches automatically between terrestrial or satellite sources </li></ul><ul><li>See, for example, http://www.motorola.com/cgiss/LA/products/systems/span/MobileWorkStat520.htm </li></ul><ul><li>Trucking industry is a big customer </li></ul>
  28. 28. Metricom <ul><li>Provides gateways to Internet, phone system, or corporate networks </li></ul><ul><li>Service offered in several cities and on university campuses, some K-12 systems, and at the Sun Microsystems campus </li></ul><ul><li>Numerous radio nodes attached to street lights, utility poles, or on rooftops </li></ul><ul><li>Customer initiates communication </li></ul><ul><li>Radio nodes are not all connected to wireline </li></ul><ul><li>28.8 Kbps secure, in 902 - 928 MHz range </li></ul>
  29. 30. Point and Multipoint Distribution Services <ul><li>Rely on terrestrial microwave connections </li></ul><ul><li>For video, voice, data service to individuals or subscriber groups </li></ul><ul><li>One way or interactive </li></ul><ul><li>Normally intended for fixed service </li></ul>
  30. 31. Multichannel Multipoint Distribution Service <ul><li>MMDS </li></ul><ul><li>Distributes video using 2600 - 2700 MHz range </li></ul><ul><li>Transmitters send line of sight signals to small antennas at subscriber homes </li></ul><ul><li>Recent conversion to digital enables about 100 channels, with 300 channels and 40 mi radius expected at maturity </li></ul>
  31. 32. MMDS Providers and Customers <ul><li>Fewer than 1M subscribers in North America, but trend is upward </li></ul><ul><li>Attractive in developing countries because it saves the high cost of stringing coax </li></ul><ul><li>Some providers are now offering Internet connectivity service at T1 downstream and 512 Kbps upstream </li></ul><ul><li>Cisco WT2700 Wireless Technology Suite uses multipath techniques </li></ul><ul><ul><li>Includes subscriber transceivers for about $500 and hub equipment capable of supporting 3000 subscribes for $150,000 </li></ul></ul>
  32. 33. LMDS <ul><li>Local Multipoint Distribution Service </li></ul><ul><li>27.5 - 31.3 GHz </li></ul><ul><li>Cell radius of 2 to 7 miles </li></ul><ul><li>Needs about 30 transmitters to cover same area as one MMDS transmitter </li></ul><ul><li>Competitive in performance with conventional CATV </li></ul><ul><li>Provides data at 2 Gbps down and 200 Mbps up </li></ul><ul><li>See http://www.wired.com/news/topstories/0,1287,1821,00.html </li></ul>
  33. 34. LMDS Commercialization <ul><li>Speedus.com delivers video and data to customers in NYC to 6 inch dishes in their windows </li></ul><ul><ul><li>Residential service is about $60/month </li></ul></ul><ul><ul><li>48 Mbps Internet access </li></ul></ul><ul><li>Evolium LMDS </li></ul><ul><ul><li>3.5 - 38 GHz; cells several kilometers in diameter </li></ul></ul><ul><ul><li>High speed voice and data to business and home offices </li></ul></ul><ul><ul><li>Many very successful field trials in Europe </li></ul></ul>
  34. 35. Wireless LANs <ul><li>Scope of operation is usually confined to a single building or less </li></ul><ul><li>Potentially huge emerging market, but it will grow slowly, as most LAN users have invested heavily in sophisticated cable plants </li></ul>
  35. 36. Infrared Wireless LANs <ul><li>line of sight </li></ul><ul><li>1 meter distance limitation </li></ul><ul><li>30 degree aperture </li></ul><ul><li>IrDA has developed a data communication standard, with most common speed 115.2 Kbps </li></ul><ul><li>IrDA supported by Windows CE, Windows 95/98, Windows 2000, and Macintosh </li></ul>
  36. 37. IEEE 802.11 Wireless LAN Standard <ul><li>All wireless LAN products that conform to this 1997 standard are interoperable </li></ul><ul><li>Non-compliant LANs will not compete successfully </li></ul><ul><li>Operate in 910 - 928 MHz or 2.4 - 2.5 GHz bands (or IR) </li></ul><ul><li>802.11 is suitable for high data rate applications such as bar code readers, rental car return, warehouse merchandise tracking, hospital patient care, meter reading </li></ul><ul><li>LANs separated by 20 to 30 miles can be tied together using appropriate antennas </li></ul>
  37. 38. Home Radio Frequency (HomeRF) <ul><li>SWAP (Shared Wireless Application Protocol) </li></ul><ul><ul><li>PCs, peripherals, cordless phones can share data within a household range </li></ul></ul><ul><ul><li>HomeRF Working Group leads the standards initiative </li></ul></ul><ul><ul><li>Products for in-building shared high speed Internet access are planned </li></ul></ul><ul><ul><li>2.4 GHz spread spectrum; 1 Mbps up to 11 Mbps </li></ul></ul><ul><ul><li>See http://www.homerf.org/about.html </li></ul></ul>