Joint range adjustment and channel assignment for overlap mitigation in dense WLANs

Dense wireless networks require advanced interference management for the performance improvement. In carrier sense multiple access with collision avoidance (CSMA/CA) networks, the mutual interference can be modeled as the overlap area, and range adjustment, such as transmission power control (TPC) and dynamic channel assignment (DCA), is effective to reduce the overlap area. A game-theoretic framework is utilized to construct a joint TPC and DCA scheme which reduces the total overlap area. Although the evaluation of the overlap area requires topology of neighboring APs, i.e., received power levels among neighboring APs are required, the proposed scheme does not require such information because decomposed overlap areas between any two APs are utilized. Moreover, unilateral improvement dynamics of channel assignment are guaranteed to converge to a Nash equilibrium because the game is shown to be a potential game. We evaluate the proposed scheme through simulations and experiments. Simulation results reveal that the proposed joint TPC and DCA scheme effectively reduces the total overlap area compared to another game-theoretic interference management scheme particularly when the number of APs is large. It is because the proposed scheme can efficiently manage the coverage overlap even when there is a variation in transmission power level. Experimental results demonstrate the convergence of the proposed scheme in a real environment.