协作频谱感知中的信道搜索机制优化

频谱感知是认知无线电网络中需要解决的首要问题。为了提高频谱感知的整体性能,该文对链路层的协作频谱感知机制进行了研究,针对其中的信道搜索感知场景,提出了一种联合优化信道搜索方案。在该方案中,基站根据各信道的空闲概率大小,选择最优的信道搜索次序,并对不同信道的搜索时长进行一定的加权处理,确保以较长的时间优先搜索空闲概率较大的信道,从而使按需信道搜索过程的切换延迟以及由此造成的QoS损失最小化。仿真实验的结果显示,这种联合优化搜索方案在信道搜索场景下的平均搜索时长始终小于现有的2种搜索方案,这说明其搜索性能具有明显的改善。

Optimization of the Channel Searching Mechanisms in Cooperative Spectrum Sensing

Spectrum sensing has been identified as the fundamental issue in cognitive radio networks(CRNs).To improve the overall sensing performance,the mechanisms of cooperative spectrum sensing are investigated.Specifically,aiming at the sensing scenario of channel searching,a joint optimized channel-searching scheme is proposed.In this scheme,the base station chooses the optimal searching sequence according to the channels’ static probabilities of being idle,and meanwhile,sets the searching durations of each candidate with different weights.Utilizing this optimal mechanism,the channels with higher idle probabilities can be guaranteed to be searched with higher priorities and longer durations,and thus,the delay due to channel switching and the corresponding QoS loss are minimized.The simulation results show that the average time for finding a new available channel by the proposed searching scheme is always much shorter than that of two existing schemes,and thus,visible performance improvement can be obtained.