基于能量检测的用户选择协作频谱感知

摘要

协作频谱感知(collaborative spectrum sensing,CSS)检测结果的上报尽管能够改善检测性能,但是也可能导致认知用户(secondary users,SU)产生较高的开销,同时引起对授权用户(primary users,PU)的干扰.基于双门限能量检测的用户选择CSS 策略,称为双门限最佳选择上报(double threshold best selection reporting, DTBSR)策略,意在减少SU的平均检测时间和提高频谱感知的性能.单门限能量检测在受到噪声干扰后性能会严重下降,采用了基于最大比合并(maximum ratio combining,M RC)的双门限能量检测算法,通过考虑信息上报过程对PU 产生的干扰,设计了在瑞利衰落信道下DTBSR策略与传统策略的虚警概率和检测概率表达式.仿真结果表明,与传统策略和最优选择上报策略相比,改进的策略能够提高检测性能并减少平均检测时间,并且还可以通过调节感知时间获得最小化漏检概率.%Although collaborative spectrum sensing(CSS)can improve the detection probability,CSS may cause a high sensing overhead to secondary users(SU)and induce much interference to primary users(PU)due to detection result reporting.A CSS strategy based on double-threshold best-selection reporting is proposed, which is called double threshold best selection reporting(DTBSR)aiming at reducing the average detection time of SU and improving the performance of spectrum sensing.The performance of single-threshold energy detec-tion is severely degraded due to noise.A double-threshold energy detection algorithm based on the maximum ra-tio combine(MRC)is adopted.By considering the interference impact on decision reporting from PU,we derive closed-form expressions of false-alarm probability and detection probability over Rayleigh fading channels for traditional and DTBSR strategies are derived,respectively.Comparing with the traditional strategy and the su-perior selective reporting strategy,the numerical and simulation results show that the improved strategy can im-prove the detection performance and reduce the average detection time of SU,and can also minimize the proba-bility of missed detection by adjusting the sensing time allocation.