关键词: 频偏与信道联合跟踪, 期望最大化(EM), 变分推断

Abstract:

A joint carrier frequency offset (CFO) and channel tracking method for multiple-user multiple-input-multiple-output orthogonal-frequency-division-multiplexing (MU-MIMO-OFDM) uplink systems is proposed in this paper.We use the expectation maximization (EM) algorithm to solve the nonlinear problem,and use variational inference to approximate the posterior distribution of the latent variable.Besides,to reduce the impact of channel estimation deviation,we consider its distribution when estimating the RCFO.Simulation results show that the proposed algorithm obtains high tracking accuracy,and there is no error floor problem in the high SNR region.

Key words: joint carrier frequency offset and channel tracking, expectation maximization, variational inference