一种低比特量化的OFDM同步方法研究与实现

Research and Implementation on OFDM Synchronization Method with Low-Bits Quantization

为了实现低复杂度高性能的正交频分复用(OFDM)符号同步,本文提出了一种基于2 bit非均匀量化的低复杂度同步方法.采用幅值映射的方法,将接收信号和本地序列用1 bit符号位和1 bit幅度位进行表示,从而将同步过程中的相关运算转化为简单的比特异或和加法运算.同时,针对2 bit量化过程中的量化门限和映射幅度选择问题,提出了一种最优量化门限及映射幅度仿真搜索算法.通过仿真对所提同步方法在AWGN和EPA多径信道条件下的同步性能进行了验证,仿真结果表明所提方法在2 bit量化条件下可获得逼近传统3 bit量化的同步性能.通过对同步模块的FPGA实现,验证了所提方法具有较低的实现复杂度.

In order to realize accurate OFDM symbol synchronization with low complexity,a resource efficient synchronization method was proposed based on 2 bit non-uniform quantization.Firstly,mapping the received signal and the local training sequence to 2 bit message represented by a sign bit and a magnitude bit,the correlation operation was implemented consequently with XOR operation and addition operation.And then,the optimal quantization threshold and magnitude value searching method were presented via simulation.Some simulation experiments were carried out to validate the synchronization capability of the proposed method in the Additive White Gaussian Noise(AWGN)and EPA multi-path channel conditions respectively.The experimental results show that the proposed synchronization method in 2-bit quantization can achieve almost the same performance with tradition 3-bit quantization.Finally,a synchronization module was implemented in FPGA,showing a lower implementation complexity of the proposed method than tradition methods.