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5 GHz WLAN

5 GHz WLAN. Tapio Sokura tapio.sokura@iki.fi. 26.3.2003. Agenda. Early Wireless LANs Current standards 5 GHz IEEE 802.11a/h ETSI HiperLAN/2 The king of the hill Compatibility Conclusions. Early Wireless LANs. Military applications as early as WW II

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5 GHz WLAN

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  1. 5 GHz WLAN Tapio Sokura tapio.sokura@iki.fi 26.3.2003

  2. Agenda • Early Wireless LANs • Current standards • 5 GHz • IEEE 802.11a/h • ETSI HiperLAN/2 • The king of the hill • Compatibility • Conclusions

  3. Early Wireless LANs • Military applications as early as WW II • ALOHAnet connected the Hawaiian islands in 1970s • CSMA was born here • Proprietary WLANs in the 1990s • typically 2 Mb/s on the 900 MHz (USA) and 2.4 GHz (USA & rest of the world) ISM-bands

  4. Current standards, IEEE • 1997: 802.11 (2.4 GHz, 2 Mb/s) • 1999: 802.11b (2.4 GHz, 11 Mb/s) • 1999: 802.11a (5 GHz, 54 Mb/s) • 2000: Wi-Fi certification began for 802.11b • Estimated: • summer 2003: 802.11g (2.4 GHz, 54 Mb/s) • end of 2003: 802.11h, Europe-compatible 802.11a • end of 2003: 802.11i, security enhancements

  5. Current standards, ETSI • HIgh PErformance Radio LAN • 1998: HiperLAN/1 • 5 GHz, 23 Mb/s • general wireless technology for portable devices • 2000: HiperLAN/2 • 5 GHz, 54 Mb/s • same as above + wireless LANs

  6. Why 5 GHz? • The need for more speed and capacity • requires more bandwidth • 2.4 GHz WLAN-band is only 83 MHz wide • 5 GHz WLAN-bands cover 100-455 MHz depending on country • Less interference from other devices • 2.4 GHz ISM-band has many other users, such as Bluetooth and microwave owens • Next stop: 17 GHz?

  7. Global problems with 5 GHz • WLAN-usable frequency allocations differ • Maximum power levels and indoor/outdoor usage restrictions differ • European requirements for 5 GHz WLANs: • Dynamic Frequency Selection, DFS • Transmit Power Control, TPC • 802.11h will support DFS & TPC

  8. 5 GHz band plan Original by Martin Johnsson: http://www.hiperlan2.com/presdocs/site/whitepaper.pdf

  9. IEEE 802.11a • 5 GHz, 54 Mb/s, OFDM, CSMA/CA • no QoS, broken WEP security as in 802.11b • up to 19 non-overlapping channels available depending on country • only 3-5 non-overlapping channels in 802.11b • The only practical differences to 802.11b are in the physical layer.

  10. ETSI HiperLAN/2 • 5 GHz, 54 Mb/s, OFDM, TDMA • physical layer is compatible with 802.11a/h • aimed to be a general wireless access solution • support for Quality-of-Service built-in • compatible with ATM, 3G, LAN... architectures • advanced features: • one- and two-way authentication, 3DES encryption • dynamic frequency selection, transmit power contr.

  11. Future king of the hill (1/2) • HiperLAN/2 is technically superior to 802.11a • but there are no HiperLAN/2 products in the market (estimated price should be about the same) • 802.11a has many supporters (incl. Wi-Fi) and it’s based on proven technology • and it’s available in the shops now • 802.11h will make it easier for manufacturers to offer their products in Europe

  12. Future king of the hill (2/2) • Does a typical user really need more speed? • many mobile and PDA users will be happy with 802.11b for a long time to come • 802.11g offers 54 Mb/s on 2.4 GHz (only 3 channels) and is compatible with 802.11b • If something radical doesn’t happen with HiperLAN/2, 802.11a/h will dominate 5 GHz

  13. Compatibility • IEEE 802.11a/h, ETSI HiperLAN/2 and MMAC (Japan) are compatible in the physical layer • it should be possible to use common hardware and change only the soft/firmware between standards • 802.11a/h is not compatible with 802.11b, dual-band access points are needed to cover both • 802.11g is compatible with 802.11b

  14. Conclusions • 802.11b will be around for a long time • WLAN speed is usually not an issue for mobile or PDA users • 802.11a/h will probably dominate 5 GHz • 802.11g gains ground on 2.4 GHz, especially in areas that don’t allow 802.11a • HiperLAN/2 is in serious danger of becoming (or staying) a dead standard. Betamax anyone?

  15. References • HiperLAN/2 Global Forum, http://www.hiperlan2.com/ • ETSI BRAN, http://portal.etsi.org/bran/ • Ficora band plans, http://www.ficora.fi/ • IEEE 802.11 Working Group, http://grouper.ieee.org/groups/802/11/

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