单载波频域均衡技术的定时同步研究

Timing synchronization for SC-FDE

针对符号定时误差容易引起单载波频域均衡(SC-FDE)调制中的符号间干扰问题,提出了一种符号定时同步的新算法.该算法基于IEEE802.16推荐的帧结构,利用多个前导字的独立互相关特性和数据序列中插入的独特字(UW),对定时误差进行初始估计,并用内插环路进行定时估计误差的跟踪,获得定时同步结果.计算机仿真结果表明,在白高斯噪声信道和多径衰落信道条件下,该算法定时估计结果的方差和均值与理想条件下的结果一致,定时误差出现概率集中在正确位置.与传统定时同步方法相比,该算法可以获得精确的符号定时同步性能,且不增加系统的运算资源.

Aimed at inter-symbol interferences easily caused by the symbol timing offset in single carrier modulation systems with frequency domain equalization （SC-FDE）, a novel algorithm for symbol timing synchronization was proposed. According to the recommended frame structure of IEEE802.16, the independent correlation of multiple preambles and the unique words （UW） in data sequence were adopted in the algorithm, and the initial timing offset was estimated. The timing offset tracking loop was performed by an interpolator and then timing synchronization was acquired. The computer simulation results show that under additive white Gaussian noise and multi-path fading channels, the mean and the square mean data of timing estimation using the algorithm are consistent with data under the ideal channel. The present probability of timing estimation offset converges at the precise position. The proposed algorithm can achieve more accurate symbol timing synchronization compared with the conventional timing method, and doesn＇t need more computing resource of the system.