分布式MIMO-OFDM系统多频偏盲估计

Blind Multiple Frequency Offsets Estimation for Distributed MIMO-OFDM Systems

针对多径信道下分布式多输入多输出正交频分复用系统多载波频偏估计问题和多频偏盲估计难、现有盲估计方法较少的情况,利用多径信道下分布式多输入多输出正交频分复用信号模型与盲源分离领域中信号模型类似的特点,利用卷积混合盲源分离思想,去除接收信号的多径影响及模糊度,得到只含频偏的发送信号,将多维频偏估计问题变成单维估计问题,最后用单个信号频偏盲估计算法得到频偏估计值.仿真结果表明,提出算法适用于更为复杂的多径信道和正交频分复用信号,具有比导频辅助方法更优的估计性能.在5 d B信噪比下,多频偏盲估计的均方误差可达10-6.

An algorithm of multiple frequency offsets estimation for distributed multiple input multiple output orthogonal frequency division multiplexing（ MIMO-OFDM） systems was discussed. Accounting for the difficulty and lack of blind estimation methods,the scheme uses the deconvolution blind source separation（ BSS） to distract the effect of multipath and ambiguity and obtain the frequency offset signals by considering that the characteristics of the multipath signal model is similar to the signal in BSS. The multidimensional frequency estimation problem is thus turned into multiple single dimension problems,and then the frequency offset value is obtained by a single frequency offset estimation algorithm. Simulations indicate that the proposed algorithm has better performance in estimating the frequency offsets than pilotsaided ones. Under signal noise ratio（ SNR） of 5 d B,the mean square errors of the carrier frequency offset（ CFO） reaches to 10- 6.