基于DMF的Rake接收机的捕获性能分析

Study of Acquisition in a Rake Receiver Based on Digital Matched-filter

对数字匹配滤波器(DMF)的Rake接收机的捕获性能进行了深入讨论,利用状态转移图推导出频率选择性信道下Rake接收机的平均捕获时间的表达式,并进行了数值分析。得出的主要结论是:DMF的Rake接收机具有很快的捕获速度;对于频率选择性信道,接收信号存在可以分离的多径分量,采用Rake接收机的检测性能要比常规接收机的检测性能好;Rake接收机的抽头数越多,平均捕获时间就越长,捕获性能就越差;Rake接收机的抽头数越多,门限取值范围就越宽。

The Rake receiver based on digital matched filter （DMF） is studied extensively in order to investigate the performance of the PN code acquisition. By using the state transition diagram, the authors derive the analytic expressions of the mean acquisition time of the Rake receiver based on DMF over frequency-selective channel. Numerical analysis is also given. It is shown that the proposed Rake receiver based on DMF can accelerate the process of PN code acquisition. Because there are many resolved muhipath components over frequency-selective channel, the detection probability of Rake receiver is larger than the conventional receiver. If more fingers of Rake receiver are available, then the mean acquisition time is longer and the threshold of detector can be set more widely.