Opportunistic multichannel access with decentralized channel state information

This paper considers multiaccess control for the uplink in orthogonal frequency division multiple access wireless networks. To avoid the extensive information exchange associated with centralized approaches, we formulate the decentralized access control problem with the contention power constraint as a Bayesian game, mapping time-varying channel state information into contention strategies. By exploiting the problem structure, a strategy where users access the channels with probability one if the observed channel gain is above a predetermined threshold is shown to be optimal. It is also shown that the energy consumption of the threshold strategy will not exceed that of randomized strategies. The game is then equivalently reformulated as one of finding the threshold value in a distributed manner, and the existence and uniqueness of Bayesian Nash equilibria is established. A distributed algorithm based on Lagrange duality is proposed to approach the unique equilibrium, and the algorithm is shown to be globally stable. In a homogeneous system, the performance loss of the proposed scheme is proved to be bounded compared with a centralized channel allocation scheme. Contrary to other proposals, our method allows for heterogeneous channel state information and achieves a comparable throughput with reduced power. Copyright (c) 2013 John Wiley & Sons, Ltd.