频谱异构认知无线电中基于吞吐量降的空时频谱机会感知

Spatial-temporal Opportunity Sensing Based on Throughput Loss in Spectrum-heterogeneous Cognitive Radio

在认知无线电(CR)中,频谱感知是实现动态频谱接入的关键技术之一。为适当保护主用户并最大化次级用户的性能,目前大部分相关工作均是用虚报概率和漏检概率作为感知度量来确定最佳感知参数的。但这种度量是用主次用户的碰撞概率来衡量次级用户对主用户的影响的,没有考虑干扰强度的影响,仅适合同构频谱环境;在不同位置次级用户有不同接入机会的异构频谱环境中,并不能最大化频谱利用率。为此,该文首先定义了吞吐量降,并提出在异构频谱环境下采用吞吐量降作为一种新的感知度量。吞吐量降是指由于次级用户占用授权频谱而导致主用户吞吐量下降的百分比。在衡量次级用户对主用户的影响时,它综合了主次用户的碰撞概率和干扰强度两个因素;其次,研究了以吞吐量降为约束的次级用户吞吐量优化问题。最后,数值仿真证实了该方案比目前几种传统方案的频谱利用率显著提高。

Spectrum sensing is a key technology to enable dynamic spectrum access in Cognitive Radio （CR）. To ensure that primary users are properly protected while maximizing the performance of secondary users, most related work considers the metrics of probabilities of missed detection and false alarm for determining optimal spectrum sensing parameters. However, these metrics only take account of the collision probability between primary user and secondary user to measure the performance impact on primary user. Since it fails to consider the impact of intensity of interference, it only adopt to homogeneous spectrum environment. In heterogeneous spectrum environment where the access opportunities of secondary user are differed by its positions, it can not maximize the spectrum utilization efficiency. So, in this paper, a new metric, throughput loss is proposed for spatial-temporal opportunity sensing firstly. Throughput loss is the average throughput loss percentage of primary user due to secondary user accesses the authorized spectrum. It is a comprehensive metric measuring impact of secondary user on primary user, and contains the collision probability and intensity of interference of two factors. Then secondary user throughput optimization problem based it is addressed. Finally, theoretical analysis and numerical simulations show that the new spectrum sensing technology proposed in this paper improves significantly the spectrum utilization efficiency compared with some traditional sensing technologies.