Cognitive access algorithms for multiple access channels

This paper considers a multiple access fading channel where each terminal has a different belief about the channel states and adapts its transmission policy to the belief. In this setting, frequency division multiple access (FDMA) and channel aware random access (RA) are two special cases. To find solutions for general cases, we formulate the problem as a Bayesian game in which each terminal maximizes the expected utility based on its belief. We show that optimal solutions for both FDMA and RA are equilibrium points of the game. Therefore, the proposed game theoretic formulation can be regarded as general framework for multiple access channels. Furthermore, we develop a cognitive access algorithm that solves the problem approximately. Numerical results show that the proposed algorithm achieves good performance and is adaptable to different levels of channel beliefs.