DS/FH混合扩频系统快速捕获新算法

针对DS/FH (Direct Sequence/Frequency Hopping)混合扩频系统捕获时间长的难题,提出了一种基于可变跳频速率的捕获算法.对搜索过程中频率未对准状态进行快速出局处理,降低平均捕获时间;对准状态则通过较长时间来验证以降低虚警概率.通过状态流图,导出了新算法在高斯白噪声信道和典型干扰环境下的平均捕获时间计算公式、检测概率、漏警概率和虚警概率.仿真结果表明,在高斯白噪声环境下,选取合适的门限,平均捕获时间可减少为传统快速扫描法的1/4;在干扰环境下,新算法鲁棒性优于后者.

Novel rapid acquisition algorithm for hybrid DS/FH spread spectrum systems

To improve the mean acquisition time performance of hybrid DS/FH spread spectrum systems, a rapid acquisition algorithm based on alterable frequency hopping rate was proposed. The unaligned states frequencies were excluded to fast decrease mean acquisition time, while the acquisition was declared after adequate verification to decrease false alarm probability. The closed form expression of the mean acquisition time was obtained with the state diagram in additive Gaussian noise channel and typical jamming environment, and the probabilities of detection, missing, and false alarm were derived. The simulation results show that, in the circumstance of additive Gaussian noise channel, the mean acquisition time with the optimal threshold is decreased almost 1/4 of the one using the tradition fast scanning method and the new algorithm is more robust under jamming.