空时编码结合连续相位调制系统中的定时估计

Timing estimation in space-time coding systems combining with continuous phase modulation

针对瑞利衰落信道中突发模式的空时网格编码的多电平连续相位调制(STTC-MCPM)系统,提出了一种基于数据辅助的符号定时估计算法.在每根发射天线传输突发包前同时插入一段相同的、已知的训练序列,每根接收天线根据各自接收信号计算出相应的训练信号,将得到的信号进行相隔一个码元的差分、求相位后,对其进行离散傅里叶变换(DFT).符号定时偏差可以从DFT的一次谐波分量的相位中估算得到.Matlab仿真结果表明,在准静态的平坦瑞利衰落信道中,定时估计误差的方差和非理想同步情况下误帧率(FER)性能的下降都非常小,该算法能快速准确地估计出初始定时偏差.

A data aided symbol timing estimation algorithm was proposed for burst-mode space-time trellis coded multi-level continuous phase modulation （STTC-MCPM） systems in Rayleigh fading channels. An identical and known training sequence was embedded before transmission of each packet of each transmit antenna at the same time. Each receive antenna first calculated the corresponding training signals from the separately received signals, and then the digital Fourier transformation （DFT） of the phase of the onesymbol differential signals of the obtained ones. The symbol timing offset could be estimated from the phase of the tone component of the DFT outputs. Matlab simulation showed that for quasi-static flat Rayleigh fading channels, the variance of the timing estimation error and the performance degradation of the frame error rate （FER） under non-ideal synchronization conditions were very small, This algorithm can estimate the initial timing offset rapidly and accurately.