Channel segregation based dynamic channel assignment for WLAN

In a frequency reusing wireless local area network (WLAN), the co-channel interference (CCI) environment will change when new access points (APs) join the network. Therefore, the user throughput reduces if the available channels are not properly re-allocated. A newly joined AP is designed to measure the CCI levels on the available channels to select the best channel which experiences the lowest CCI (this is referred to as the conventional channel assignment). However, old APs' channels are not anymore the best since the CCI environment has changed after the new one joined. If each AP periodically measures the CCI environment and reselects the channel experiencing the lowest CCI, the throughput may improve. This is called the dynamic channel assignment (DCA). In this paper, we apply the channel segregation based DCA (CS-DCA) to WLAN. In order to examine the channel distribution pattern obtained by CS-DCA, we introduce three indicators: the autocorrelation of channel distribution pattern indicating the degree of stability, the deviation of channel reusing, and the minimum co-channel AP distance. We confirm by computer simulation that the CS-DCA can autonomously form a channel distribution pattern which minimizes the CCI at each AP and that the CS-DCA improves the signal-to-interference-ratio (SIR) compared to the conventional scheme.