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 äIf 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/