On the resource allocation for multi-relay cognitive radio systems

In this paper, we investigate the resource allocation problem in an OFDM-based cognitive radio system with multiple relays. We address the formulated intractable problem by a two-stage procedure which corresponds to two subproblems: subchannel allocation and power distribution. For each subproblem, a fast algorithm is proposed by exploiting its special structure. Our proposed algorithms can achieve performance close to the upper bound. The remarkable characteristic of the proposed algorithm is that the approximate linear complexity is significantly lower than that of standard techniques, making it promising for applications. Simulation results also validate the superior performance of the proposed algorithm.