π/4-DQPSK信号的多普勒频移快捕和跟踪  

Rapid Acquisition and Tracking of Doppler Frequency Shift for π/4-DQPSK Signals

作　　者：吴团锋[1,2] 徐友云[1,2] 归琳[1] 马文峰[2] 

机构地区：[1]上海交通大学无线通信技术研究所,上海200240 [2]解放军理工大学通信工程学院,江苏南京210007

出　　处：《无线电通信技术》2011年第5期9-12,共4页Radio Communications Technology

基　　金：国家自然科学基金(60625103);上海市数字媒体处理与传输重点实验室资助项目

摘　　要：提出了一种适用于数字卫星移动突发通信系统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，利用独特码的调制输出进行多普勒频移的快捕，并根据π/4-DQPSK信号的特点，采用判决反馈PLL环跟踪多普勒频移的变化。仿真结果表明，采用该方法的解调器误比特率．Pb与成形滤波器的滚降系数n无关。多普勒频移在-Rs／2～Rs／2范围内变化时，对解调器的误比特率Pb没有影响。This paper presents a new algorithm of rapid acquisition and tracking of Doppler frequency shift for π/4-DQPSK signals, which is suitable for digital satellite mobile burst communication system. The Doppler frequency shift acquisition is performed by modulated signals of unique word and the decision feedback PLL is employed to track Doppler frequency shift. The simulation results show that the performance of demodulator is independent of rolloff-factor a, and the simulation results also indicate that Doppler frequency shift range from - Rs/2 - Rs/2 has no effect on bit error rate Pb.

关 键 词：数字卫星移动突发通信系统 Π/4-DQPSK 多普勒频移 独特码 判决反馈PLL环 

分 类 号：TP911.3[自动化与计算机技术]