Interference type based channel management using adaptive bandwidth in wireless LANs

In IEEE 802.11 based Wireless LANs, the channel bandwidth is considered as a fixed parameter. Recently, the concept of adaptive bandwidth has been newly introduced, making it possible to allocate the channel bandwidth adaptively according to the interference type of users. Such a capability enables to enhance the previous way of channel usage where each Access Point (AP) is restricted to use a fixed bandwidth channel to serve all users. In this paper, we propose a scheme where each AP is allowed to use an adaptive bandwidth channel that is adjusted by a central controller. The channel bandwidth is determined according to whether a user to be served experiences interference or not. If the user is vulnerable to interference from other APs, not its serving AP, it is served through a channel assigned to the serving AP. On the contrary, when serving interference-free users, the AP can exploit more bandwidth which is available at the moment. In this way, our proposed scheme can enhance the spectrum utilization of interference-free users without harming the other users. Simulation results show that our scheme significantly improves the average spectrum utilization of each AP.