认知无线电中基于截断序贯检测的频谱感知技术

Truncated Sequential Detection for Spectrum Sensing in Cognitive Radio

序贯检测的检测时间是随实际接收信号采样点的变化而不同的随机变量,在平均意义上,序贯检测有较高的检测速度,但是个别情况下可能需要很长的检测时间,为了避免这种现象的发生,同时提高认知无线电中频谱感知的速度,该文提出了一种截断序贯检测算法。首先分析了截断对传统序贯检测性能的影响,给出了虚警概率和漏检概率的上限,然后基于该性能上限得到了截断序贯检测的检测门限,最后给出了截断序贯检测算法的流程。仿真结果表明,该算法在有限的检测时间内,能够满足系统的性能要求,且其平均检测时间小于传统的能量检测。

The detection time required to reach a decision in sequential detection is a random variable.Although the sequential detection has a high average detection speed,very long detection time may be required in some specific cases.In order to improve the speed of spectrum sensing as well as to avoid some too-long-sensing-time tests in cognitive radio,a truncated sequential detection algorithm is proposed.Firstly,the effect of truncation on the performance of conventional sequential detection is analyzed,and the upper bounds of the false alarm and the miss detection probability are derived.Then the detection thresholds of truncated sequential detection are derived based on the upper bounds.Finally,the process of the truncated sequential detection algorithm is proposed.The simulation results show that the proposed algorithm,under the constraint of limited sensing time,can satisfy the performance requirement,and still have a shorter average sensing time than the conventional energy detection does.