Multi-channel packet capture in 802.11b/g wireless networks

Wireless intrusion detection systems (WIDS) for 802.11a/b/g networks often use a channel hopping scheme to scan for activity. A common assumption is that packet detection and decoding can only occur when the receiver is tuned to the same channel as the transmitter. The potential for packet detection and decoding on adjacent channels, both in the case of overlapped and non-overlapped channels, is investigated and analyzed using a wireless test bed with multiple transmitters and receivers. It is shown that under certain conditions 802.11b/g packets can be detected and properly decoded at 1 and 2 Mbps on overlapped and even nonoverlapped channels.