Vanligtvis är det 54 Mbit/s man talar om när det gäller IEEE 802.11a standarden, men lite letande på nätet ger oss detta:
The de facto standard for 802.11a networking appears to be 54 Mbps. Data rates of 54 Mbps are achieved by using 64QAM (64-level quadrature amplitude modulation), which yields 8 bits per cycle or 10 bits per cycle, for a total of up to 1.125 Mbps per 300-KHz channel. With 48 channels, this results in a 54-Mbps data rate. Atheros offers an additional proprietary mode that combines two carriers for a maximum theoretical data rate of 108 Mbps and conservatively estimates that data rates of 72 Mbps will be possible when using its proprietary dual-channel mode.
Det verkar som om det alltså går att nå 108 Mbit/s, men mig inte förklara detta i detalj bara... Om det är denna teknik Proxim använder vet jag dock inte.
Läs mera här: http://www.networkcomputing.com/1201/1201ws1.html
Förövrigt så är det inte säkert att denna produkt (eller en framtida Airport baserad på IEEE 802.11a) går att använda hursomhelst i Europa. Det beror på att 802.11a använder sig av 5 GHz-bandet, medan 802.11b (som används i Airport idag) använder 2,4 GHz-bandet. 2,4 GHz är fritt i princip överallt, medan 5 GHz inte är det. För lite mer tekniskt snack (från samma artikel som ovan):
Devices using 802.11b enjoy international acceptance because the 2.4-GHz band is almost universally available. Where there are conflicts, the vendor can implement frequency-selection software that prevents a radio from operating at illegal frequencies. However, the 5-GHz spectrum does not share this luxury. In the United States, 802.11a enjoys relatively clear-channel operation. But in Europe and Asia, the case is a little different. The Japanese market shares only the lower 100 MHz of the frequency spectrum, which means 802.11a applications in Japan will face more contention. In Europe, the lower 200 MHz are common with the FCC´s 5-GHz allotment, but the higher 100 MHz, reserved for outdoor applications, are taken. 802.11a needs about 20 MHz of spectrum to operate at 54 Mbps. Thus, users in the United States and Europe will have up to 10 channels from which to choose, while users in Japan will be restricted to five channels.
To complicate matters, in Europe, the HiperLAN/2 standard, led by the ETSI (European Telecommunications Standards Institute)´s BRAN (Broadband Radio Access Networks) group, has wide acceptance as the 5-GHz technology of choice. HiperLAN/2 and 802.11a share some similarities at the physical layer: Both use OFDM technology to achieve their data rates, for instance. However, HiperLAN/2 is much more akin to ATM than to Ethernet. In fact, the HiperLAN/2 standard grew out of the effort to develop wireless ATM. HiperLAN/2 shares the 20-MHz channels in the 5-GHz spectrum in time, using TDMA (time division multiple access) to provide QoS (Quality of Service) through ATM-like mechanisms.
