相干快跳频系统中基于最大似然合并的多音干扰抑制算法研究

摘要

频率子集相干快跳频系统（S-CFFH）是一种新颖的快跳频方案，可在 FFH 系统中实现有效信道估计。本文推导了 S-CFFH／BPSK 系统在多音干扰（MTJ）和瑞利衰落信道中最大似然（ML）合并的理论误码率，给出了理想估计信道时的误码率闭合表达式，也给出了非理想估计信道时在特殊情况下的误码率闭合表达式，并通过仿真验证了理论推导的正确性。仿真结果表明 S-CFFH／BPSK 系统中的 ML 合并与最大比合并（MRC）相比有显著的干扰抑制增益，并且有效降低了干扰方的干扰效率；与非相干 FFH／BFSK 系统的 ML 合并相比，随着信干比的增大，S-CFFH／BPSK 系统的 ML 合并展示出显著的性能增益。%Subset based coherent fast frequency hopping (S-CFFH)is a novel FFH scheme,which enables efficient chan-nel estimation for FFH signals.In this paper,we study the analytical bit error ratio (BER)of the S-CFFH/BPSK with maximum likelihood (ML)combining in the presence of multitone jamming (MTJ)and Rayleigh fading channels.Closed-form BER expressions are presented with perfect channel state information (CSI),and for special cases with imperfect CSI. The analytical results are validated by simulation.As compared with the maximum ratio combining (MRC),ML combining not only shows significant performance gain,but also greatly reduces the jammers’efficiency.As compared with the nonco-herent FFH/BFSK with ML combining,the S-CFFH/BPSK with ML combining shows significant gain with the increase of signal to jamming ratio.