GMSK信号的维特比算法与FPGA实现  

The Viterbi Algorithm of GMSK Signal and Implement in FPGA

作　　者：康超 陈丽婷 陈建斌 KANG Chao;CHEN Liting;CHEN Jianbin(Shanghai Aerospace Electronic Technology Institute,Shanghai 201109,China)

机构地区：[1]上海航天电子技术研究所,上海201109

出　　处：《无线电工程》2018年第7期541-545,共5页Radio Engineering

基　　金：国家部委基金资助项目

摘　　要：GMSK信号与FSK信号相比具有更高的频带利用率,在遥测通信领域得到了广泛应用。因GMSK的基带信号经过高斯滤波整形,相当于加入了码间干扰导致接收灵敏度下降。采用基于最佳似然准则(MLSE)的维特比(Viterbi)算法实现GMSK信号的解调。针对所需匹配滤波器消耗过多FPGA硬件资源问题提出了优化方法,将匹配滤波器数量从256个降至64个。针对路径度量LS值发散导致FPGA无法实现问题进行了分析并提出了解决方法,使LS收敛在460附近。实测结果表明,FPGA实现后充分发挥了Viterbi算法的最佳译码性能,接收灵敏度与未采用多符号检测技术(MSD)的FSK信号相比提升了3 dB。GMSK is widely used in telemetry communication,which provides higher bandwidth efficiency over FSK.The baseband signal of GMSK shall pass a Gusses filter,which causes the sensitivity descend. This paper adopted the Viterbi algorithm based on maximum-likelihood sequence estimation to demodulate GMSK signal.This paper proposes an optimization method to reduce the numbers of suited filter from 256 to 64.And this paper also proposes a method to make LS convergence in 460.Result shows that Viterbi algorithm implemented on FPGA can exert the best performance of maximum likelihood sequence estimation. The sensitivity is 3 d B better than FSK without MSD.

关 键 词：最佳似然准则 维特比 GMSK FSK FPGA 

分 类 号：TN911[电子电信—通信与信息系统]