Subchannel and Power Allocation in OFDMA-Based Cognitive Radio Networks

Recently, there has been a great interest in cognitive radio networks. In addition, the use of subchannel allocation and power distribution in OFDM systems have been discussed in the literature and proven to help improve the capacity performance in cooperative networks. Therefore, in this paper we propose to add a primary source-destination pair to the secondary system in a cognitive radio network. We also provide the analysis of a subchannel and power allocation in cognitive networks. The optimal solution for such a problem is shown to be exponentially complex computationally. Therefore, we propose a suboptimal algorithm to reduce the complexity for which the subchannel allocation and power distribution among transmitters in the secondary system are performed in two steps. Simulation results are presented showing that the performance of the proposed suboptimal algorithm approach performs asymptotically to the optimal algorithm solution.