基于FPGA的OFDM时频同步系统的设计与仿真

同步技术是OFDM中的一项关键技术.但由于无线信道的随机性,传统方法在门限设定上无法兼顾判断准确性和计算复杂度两方面性能.针对这一问题,提出了一种将相对门限和浮动门限相结合的同步判决方法,它能够在保持判断准确性的同时降低计算时的复杂度.此外,通过交叠计算训练序列相关值的方法来提高频偏估计精度.在此基础上,详细阐述了算法关键模块的电路结构和硬件实现.仿真结果表明该算法在多径信道环境下具有较高的时间同步和频偏估计精度,能够有效地降低硬件资源消耗,节省传输带宽.

Design and Simulation of OFDM Synchronization System Based on FPGA

Synchronization is a key technology of OFDM system. However, due to the stochastic of wireless channel, the configuration of judgment threshold of traditional algorithms can not balance the computation com-plexity and judgment accuracy. A novel synchronization algorithm which combines relative threshold with float-ing threshold is proposed to solve this problem. It can reduce the calculation complexity, while maintaining judgment accuracy. By reusing the training sequence, the frequency offset estimation accuracy can be increased as well. Moreover, the key modules of circuit structure and hardware implementation of the algorithm are dis-cussed in detail. Simulation results show that under the condition of multi-path channel, this algorithm has high precision in timing synchronization and frequency offset estimation and it can save hardware resource and im-prove the bandwidth efficiency remarkably.