Abstract:

Aimed at dynamic changing of the available subcarriers in cognitive radio system, a dynamic subcarrier allocation method based on access probability is proposed. The method controls access probability of cognitive users on the subcarriers to maximize the system throughput and guarantee the quality of service requirement of the users. To simplify the solution process, a heuristic algorithm is proposed based on the access probability transfer. The algorithm transfers the subcarrier access probability among the users until the rate requirements of all users being satisfied. Simulation shows that the heuristic algorithm can achieve the global optimal solution in Rayleigh channel environment. Also it is shown that the throughput performance of the proposed method is better than current dynamic allocation and carrier sense multiple access method.

Key words: cognitive radio, Markov chain, buffering, access control, forced termination probability