Recursive Channel Estimation Algorithms for Iterative Receiver in MIMO-OFDM Systems

A practical variational Bayes (VB) iterative receiver with joint signal detection and channel estimation is proposed in this paper for MIMO-OFDM systems in time-varying multipath channel. Since the VB method provides distribution-estimates of the parameters, the soft-input soft-output (SISO) QRD-M algorithm is exploited to estimate the signal distribution, and several channel estimation algorithms including the low complexity recursive channel estimation (LCRCE) algorithm are derived for the channel distribution estimation. It is noted that the LCRCE algorithm not only completely avoids computation of matrix inversion and matrix multiplication, but also greatly reduces the recursion numbers. The simulation results show that the performance loss of the proposed receiver is only ldB for fast varying channels and less than 0.5 dB for slow varying channels at the bit error rate of 10 4 after 3 iterations, compared with the optimal receiver with perfect channel state information.