Abstract:

The frequency resuorce for satellite communication becomes rare while spectrum utilization is inefficient. To raise such a spectrum utilization efficiency, a joint optimization of detection threshold and power allocation based on Underlay cognitive radio is proposed. Firstly, the mathematical relationship among detection fusion errors, power allocation vectors and data throughput is analyzed. Correspondingly, feasibility conditions for joint allocation of channel and power are shown with the limited of channel number and transmission power. After feasibility argumentation and fusion error analysis, the joint optimization is divided into detection threshold optimization and optimal power allocation. The suitability of windowed particle swarm optimization for the downlink detection threshold is proved. The optimal solution of joint allocation of channel and power is found theoretically based on the feasibility discussion result. To get the joint optimization of detection threshold and power allocation, an intermediate variable is introduced which performs iteration between two subarithmetic repeatedly. Simulation results show the superiority of the proposed windowed particle swarm optimization over traditional methods in tems of accuracy and iteration times. Comparing the performance among the common satellite communication, Underly cognitive radio and the joint optimization, the comparison results demonstrate the throughput improvement of the joint optimization. The computation complexity is also presented.