IEEE 802.11 wireless networks have gained ever greater popularity nowadays. Handoff is a critical issue in IEEE 802.11 based wireless networks and latency in the handoff process is a major concern.
In this paper, we propose to reduce handoff latency for IEEE 802.11 wireless networks with Neighbor Graphs (NG) pre-scanning mechanisms. IEEE 802.11 uses 11 channels of which the channels 1, 6 and 11 do not mutually overlap. So these channels are expected to have a lower carrier-to-interference ratio (CI) compared to the other channels present under the same base station, which increases the channel’s availability during handoff. Based on the NG pre-scanning mechanism, when handoff criterions have been met, we design an algorithm to first scan the channels 1, 6 and 11, if present under the next Access Point (AP), to reduce the scanning delay. We also introduce pre-authentication mechanism, which will effectively reduce the message processing delay.