一种数据辅助频偏估计算法

A Data-aided Frequency Offset Estimation Algorithm

针对以往频偏估计不能兼顾估计范围和估计精度的问题,在分析和比较已有算法的基础上,提出一种基于自相关函数的频偏估计算法。将接收到的信号与辅助数据的共轭进行相关计算,然后对得到信号的自相关函数进行邻位符号相除来展开相位,得到相位差分序列,利用该序列对频偏进行估计,再对频偏结果进行加权平均,理论估计范围可达到符号速率的50%。仿真结果表明,该算法在信噪比SNR≥-5 dB的条件下,能够实现估计方差接近克拉美罗界,解决了估计范围和估计精度相矛盾的问题。

For the previous problem that the estimation range and estimation accuracy can not take into account of frequency offset estimation, a novel frequency offset estimation algorithm is proposed based on the autocorrelation function after analysis and comparison of several existing algorithms. In the algorithm, the correlation calculation between the received signal and the conjugate of local aided data is operated, then adjacent symbols of the autocorrelation function of the obtained signal are divided mutually to unwrap the phase, and the phase difference sequence is obtained and used to estimate the frequency offset, finally makes weighted average of the results. Have a detailed analysis of the performance of the proposed algorithm, theoretical estimation range can be up to 50% of the symbol rate. Simulation results show that the algorithm is able to achieve the estimated variance close to Cramer-Rao Bound（CRB） when SNR≥-5 dB. The results show that the proposed algorithm solves the contradictory problem between the estimation range and estimation accuracy effectively, which proves its practicability.