Discussion on:

Wireless LAN spectrum management

The article says that 802.11g clients drop to 802.11b mode and perfornance when 802.11b clients are present. Not exactly. Rather the 802.11g client will send either a 802.11b CTS to Self or RTS/CTS prior to each 802.11g frame it sends. These CTS or RTS/CTS frames tell the 802.11b clients that a 802.11g client has something to send, and that they should hold off any transmissions for a amount of time to allow the 802.11g to send without impacting it.

A reduction in performance of the 802.11g client is experienced due to the overhead of having to send these additional CTS and/or RTS frames - but the 802.11g client does not revert fully to 802.11b mode, and the performance impact varies with frame sizes, distance, etc. - typically experiencing a 10-40% reduction in throughput is seen for the 802.11g client in a 802.11b mixed environment.

I see 20+ mbps 11g devices droping to 3 mbps along with a 3 mbps 11b device. These are hard numbers and experiments on very detailed reports I've seen from Tomsnetworking.

the 4 channel model is fine, unless there are 3 channel model access points also in the visinity. Looks at the diagrams to see the overlap and problem.

Hotels are expiecing this issue, in that they installed with a 4 channel model - and now travelers are bringing in 'portable' or 'pocket' access points and plugging them in. These 'portable' access points are typically defaults to a 3 channel model channel.

The 2.4 GHz range is a deadend. Always go with a dualband 802.11 a/b/g solution. The miniPCI adapters are only $30 for an Intel board.