MU-MIMO-OFDM 上行频偏与信道联合跟踪

摘要

A joint carrier frequency offset (CFO) and channel tracking method for multiple-user multiple-input-multiple-out-put orthogonal-frequency-division-multiplexing (MU-MIMO-OFDM) uplink systems is proposed in this paper .We use the expecta-tion maximization (EM) algorithm to solve the nonlinear problem ,and use variational inference to approximate the posterior distri-bution of the latent variable .Besides ,to reduce the impact of channel estimation deviation ,we consider its distribution when estimat-ing the RCFO .Simulation results show that the proposed algorithm obtains high tracking accuracy ,and there is no error floor prob-lem in the high SNR region .%本文提出了一种在 MU-MIMO-OFDM （Multiple-User Multiple-Input-Multiple-Output Orthogonal-Frequency-Divi-sion-Multiplexing）上行链路中，联合跟踪残留频偏（Residual Carrier Frequency Offset ，RCFO）和信道的算法。本算法采用 EM （Expectation Maximization）方法求解该非线性问题，并使用变分推断来近似原来复杂的隐变量的后验概率。在估计 RCFO时，考虑了信道估计误差的概率分布，从而降低了信道估计误差对跟踪性能的影响。仿真中，本算法达到了较高的跟踪精度，尤其是在高信噪比时没有误差平台问题。