Joint uplink power and subchannel allocation in cognitive radio network

In this paper, we consider the resource allocation problem in the uplink transmission of an orthogonal frequency-division multiple access (OFDMA) based cognitive radio (CR) network. The resource allocation aims to maximize the uplink throughput of secondary users (SUs) in CR network under the constraints of the primary user (PU) interference and the transmit power limits of SUs. In general, the optimal joint power and subchannel allocation is known as NP-hard. To ease the computation complexity while maintain good performance, we propose a novel particle swarm optimization (PSO) based joint uplink power and subchannel allocation algorithm to solve this resource allocation problem. Due to the combinatorial nature of the resource allocation problem, our algorithm in which power continuously changes while the subchannel allocation strategy alters in the iteration process can obtain better performance than the existing decomposition based algorithm that subchannel assignment and power allocation are implemented separately. Simulation results show the effectiveness of the proposed algorithm.