Performance analysis of 802.11 DCF with limited channels

Abstract

Wireless communication has achieved great proliferation in communication technologies. IEEE 802.11 WLANs have been widely deployed as wireless access mechanism technology. To keep up with growing bandwidth and data rate requirements, legacy standards such as IEEE 802.11 have been deeply researched for their operation in multi-channel environment through usage of multiple interfaces. In the multi-channel multi-interface environment, it is common to assume that number of available channels are greater than or equal to number of interfaces. We evaluate performance of IEEE 802.11 DCF (Distributed Coordination Function) in multi-channel multi-interface environment in which number of channels are less than number of interfaces; contradicting common assumption where number of channels are greater than or equal to number of interfaces. In our study, we present scenarios under which number of available channels can become less than total number of interfaces on a node to motivate the problem. Through evaluation of accurate analytical models, we suggest that it is not possible to achieve higher average network throughput by tuning multiple interfaces on one channel. By keeping aggregate traffic constant for a channel, greater number of interfaces on a channel increases collisions, resulting in less effective usage of channel.