Resource allocation based on subcarrier grouping in OFDMA cognitive radio networks

In this paper, we investigate the subcarrier grouping based resource allocation in orthogonal frequency division multiple access cognitive radio networks. The objective is to maximize the secondary user´s minimal transmission rate, while taking into account the subcarrier grouping constraint, subcarrier allocation constraint, power allocation constraint, and the interference power constraint. The problem is formulated as a mixed integer programming problem. It can be solved by the exhaustive searching method, which has an exponential complexity. In order to decrease the computation complexity, a suboptimal fast algorithm will be developed. The suboptimal algorithm solves the subcarrier allocation and power allocation separately. By exploiting the structure of the problem, a fast power allocation algorithm based on the barrier method is proposed. Simulations have been done to verity the performance of the proposed algorithm.