Optimal power allocation for OFDM-based cooperative relay cognitive radio networks

Cognitive radio (CR) network with cooperative relay is potentially a promising technique to solve current spectrum inefficiency and spectrum scarcity problem. In this paper, we study the power allocation in cognitive radio (CR) networks with cooperative relay. The interference to the licensed primary system and the power budget of the CR network are jointly considered. The resulting model is general and the formulated optimization task generally hard to solve. To deal with the intractable coupling variables in the concerned problem, we propose an alternating optimization method, which can work out the optimal solution in an iteration manner and converges rapidly. Experiment results show that our proposed method can significantly increase system capacity, comparing with other representative ones. Furthermore, the proposed method gives a general power optimization framework for CR networks with cooperative relay and can be extended to other scenarios easily.