"Evolving Technologies for Terrestrial Wireless"

447 views
343 views

Published on

Published in: Technology, Business
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
447
On SlideShare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
9
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

"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>

×