Channel Spacing for Maximum Performance of 5 GHz WLAN Backhaul Links

This study deals to quantify the impact of Adjacent Channel Interference (ACI) in multi-radio 802.11a based wireless nodes designed for WLAN. The nodes are equipped with three 802.11a wireless interfaces, two for backhaul connectivity with directional antennas and one for Access Point (AP) functionality. Adjacent channels in 802.11a are considered to be non-overlapping and expected ACI would be almost negligible. Observed results are, 802.11a channels produces significant interference when adjacent channels are assigned in consecutive order to nodes or to the nodes which are placed in the beam of directional antennas, they are being known as directed nodes. Our work focuses mainly on backhaul of 802.11a, we propose a channel assignment technique where adjacent nodes and directed nodes are placed with spacing of one channel, Conflict graph and greedy algorithms for channel assignment to backhaul links have been used. We evaluate our technique by OPNET 14 simulations, where we quantify the effect of ACI in terms of throughput, observed results for our proposed technique have shown that the throughput of the network is doubled as compared to system where channels are assign to adjacent nodes with consecutive channels without spacing of channel.