GMSK信号的同步及相干解调算法  

Synchronization and Coherent Demodulation Algorithm of GMSK Signal

作　　者：陈丽婷 康超 顾圣明 陈建斌 CHEN Liting;KANG Chao;GU Shengming;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》2021年第5期346-351,共6页Radio Engineering

基　　金：国家部委基金资助项目。

摘　　要：高斯最小频移键控(Gaussian Filtered Minimum Shift Keying,GMSK)包络恒定、相位连续,具有较高的频带利用率和功率利用率,在频带受限的数字通信领域得到广泛应用。采用了一种低计算量和适合数字化处理的锁相环路进行载波相位同步,提出一种基于GMSK信号波形特点的符号定时以提高环路的性能,该算法结构简单,易于实现。为了获得最佳的解调性能,采用基于最佳似然准则的维特比相干解调算法,并提出简化算法,占用的FIR资源减小为原来的1/4。工程实践表明,该解调算法系统解调损耗仅为0.3 d B,具有优良的性能。GMSK is a special type of continuous phase modulation which possesses the characteristics of constant envelope and continuous phase and shows high frequency efficiency and power efficiency.It’s widely used in the field of digital communication with limited frequency band.A phase-locked loop which has a low computation and is suitable for digital processing is used to synchronize the carrier phase.A new symbol timing algorithm based on GMSK signal waveform is presented to improve the performance of the loop.This algorithm is simple and easy to implement.In order to obtain the optimal demodulation performance,the Viterbi’s coherence demodulation algorithm based on maximum-likelihood sequence estimation is adopted,and a simplified algorithm which reduces the occupied FIR resources to a quarter of the original is proposed.The engineering implementation shows that the demodulation loss of the demodulation algorithm system is only 0.3 dB and the system has excellent performance.

关 键 词：高斯最小频移键控 通用数字环 符号定时 最大似然序列检测 维特比解调 

分 类 号：TN974[电子电信—信号与信息处理]