GMSK信号的多普勒频移快捕和跟踪  

Doppler frequency shift rapid acquisition and tracking for GMSK signals

作　　者：吴团锋[1] 朱爱民[1] 杨喜根[1] 李际平[1] 

机构地区：[1]解放军理工大学通信工程学院,江苏南京210007

出　　处：《信号处理》2006年第1期114-118,122,共6页Journal of Signal Processing

摘　　要：GMSK信号具有良好的频谱和功率特性,特别适用于功率受限和信道存在非线性、衰落以及多普勒频移的数字卫星移动突发通信系统。本文提出了一种GMSK信号的多普勒频移快捕和跟踪方法。该方法根据突发通信时帧结构的特点,采用独特码和FFT并行处理信号能量检测、帧同步检测和多普勒频移快捕,并采用判决反馈PLL环跟踪多普勒频移的变化。仿真结果表明,多普勒频移在-Rb／2～Rb/2范围内变化时,与理论值相比,采用该方法的准相干解调器误比特率Pb 性能恶化仅为0．3dB。在信息速率Rb=9．6kbps时,多普勒频移速率可达4000Hz／s。As a very bandwidth-efficicnt and power-efficient modulation format, Gaussian minimum shift keying （GMSK） is important for power-limited digital satellite mobile burst communication system having nonlinear channel with fading and Doppler frequency shift. This paper presents a new algorithm of Doppler frequency shift rapid acquisition and tracking for GMSK signals. The algorithm can be done in parallel with signal acquisition, frame synchronization and Doppler frequency shift acquisition using Unique Word and FFT. Decision feedback PLL is employed to track Doppler frequency shift. Simalation results show that Doppler frequency shift range from - RU2 ～ Rb/2 degrades the bit error rate Pb performance of new quasi - coherent demodulator about 0.3dB. The Doppler rate can be as large as 4000Hz per second when the bit rate Rb is 9.6k bits per second.

关 键 词：数字卫星移动突发通信系统 GMSK 多普勒频移 独特码 判决反馈PLL环 

分 类 号：TN92[电子电信—通信与信息系统] TN958[电子电信—信息与通信工程]