Research on Power Allocation of Cognitive Radio Based on Robust Cooperative Relay

摘要

Conventional distributed power control algorithms in cognitive radio networks are based on the assumption of perfect channel estimation which may lead to performance degradation in practical systems. Considering the uncertainty of the channel, this paper proposes a robust cooperative relay-based cognitive radio joint power allocation algorithm. This robustly optimized power allocation problem can be described by a semi-infinite programming. Suppose that under the worst constraints, this problem is transformed into a second-order cone programming problem. Considering the difference between the two transmission phases of the secondary users (SUs), a fairness interference weighting factor is introduced to constrain the interference of the SUs and the relay nodes to the primary users. The OFDM technology is used to eliminate interference between the first phase and the second phase in the SU transmission process. The simulation results show that the proposed algorithm improves the system capacity of the SUs under the premise of guaranteeing the quality of the primary users. Compared with the traditional robust algorithm, the proposed algorithm has better resistance to channel perturbation and greatly improves the spatial diversity gain of the SUs.