Optimized cognitive terminal assignment strategy for coordinated spectrum sensing

This paper focuses on the optimization of coordinated spectrum sensing for cognitive radio (CR) networks using an efficient cognitive terminal (CT) assignment strategy. A metric called ineffective transmission-effective transmission ratio (ITETR) is proposed to evaluate the performance of the CT assignment strategy. Considering the diversity of channel utilization and CT sensing performance, the optimization of the proposed metric is formulated as an assignment problem. We provide a mathematical analysis as well as the related closed-form solution in the simplified case when all CTs have the same sensing performance for the same channel. Based on this analysis, an improved greedy algorithm-based strategy is proposed to determine the sub-optimal solution for the more general case, i.e., each CT exhibits different sensing performance for the same channel. Simulation results show that the proposed strategy can significantly improve the ITETR of CR networks when different channels possess different utilizations. When all channels have the same utilization, the proposed strategy yields a perfect approximation to the iterative Hungarian algorithm-based strategy while offering lower computation complexity.