基于能量检测的用户选择协作频谱感知

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,MRC)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。

User selected collaborative spectrum sensing based on energy detection

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 detection is severely degraded due to noise. A double-threshold energy detection algorithm based on the maximum ratio 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 superior selective reporting strategy, the numerical and simulation results show that the improved strategy can improve the detection performance and reduce the average detection time of SU, and can also minimize the probability of missed detection by adjusting the sensing time allocation.