The IEEE ratified the 802.11a standard in 1999, but the first 802.11a products didn’t begin appearing on the market until late 2001—and boy were they pricey! The 802.11a standard delivers a maximum data rate of 54Mbps with 12 non-overlapping frequency channels. Figure 1 shows the UNII bands.
Operating in the 5GHz radio band, 802.11a is also immune to interference from devices that operate in the 2.4GHz band, like microwave ovens, cordless phones, and Bluetooth devices. 802.11a isn’t backward compatible with 802.11b because they are different frequencies, so you don’t get to just “upgrade” part of your network and expect everything to work together in perfect harmony. But no worries—there are plenty of dual-radio devices that will work in both types of networks. A definite plus for 802.11a is that it can work in the same physical environment without interference from 802.11b users.
Similar to the 802.11b radios, all 802.11a products also have the ability to data-rate-shift while moving. The 802.11a products allow the person operating at 54Mbps to shift to 48Mbps, 36Mbps, 24Mbps, 18Mbps, 12Mbps, 9Mbps, and finally still communicate farthest from
the AP at 6Mbps.
There’s also an extension of the 802.11a specifications called 802.11h.
FIGURE 1: UNII 5GHz band has 12 non-overlapping channels (U.S.).
Operating in the 5GHz radio band, 802.11a is also immune to interference from devices that operate in the 2.4GHz band, like microwave ovens, cordless phones, and Bluetooth devices. 802.11a isn’t backward compatible with 802.11b because they are different frequencies, so you don’t get to just “upgrade” part of your network and expect everything to work together in perfect harmony. But no worries—there are plenty of dual-radio devices that will work in both types of networks. A definite plus for 802.11a is that it can work in the same physical environment without interference from 802.11b users.
Similar to the 802.11b radios, all 802.11a products also have the ability to data-rate-shift while moving. The 802.11a products allow the person operating at 54Mbps to shift to 48Mbps, 36Mbps, 24Mbps, 18Mbps, 12Mbps, 9Mbps, and finally still communicate farthest from
the AP at 6Mbps.
There’s also an extension of the 802.11a specifications called 802.11h.
FIGURE 1: UNII 5GHz band has 12 non-overlapping channels (U.S.).
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