A new scheme for power allocation in cognitive radio networks based on cooperative relay

Cooperative relay in cognitive radio networks (CRNs) can solve the problem of heterogeneity of spectrum availability among secondary users (SUs) by using relay nodes to bridge the transmitter and receiver exploiting channels common with them respectively. With the introduction of cooperative relay, power allocation over direct and relay channels at the source becomes a key problem that constraint the system throughput. In this paper, we propose a joint water-filling (JWF) algorithm, by which the power can be allocated more reasonably and the throughput is nearly optimal. Simulation results show the effectiveness of the proposed scheme.