Improved iterative joint detection and estimation through variational Bayesian inference

We propose an improved variational Bayesian (VB) receiver for orthogonal frequency-division multiplexing (OFDM) systems over frequency-selective block-fading channels. Conventional VB receivers provide distribution-estimates for the channel and information symbols iteratively and jointly. The proposed scheme is different from conventional VB inference in that the VB iterative receiver also exploits the hard channel estimate extracted from previous iterations to update the channel and symbol distributions. In this way, we reduce the impact of channel uncertainty on the decoder performance by means of a modified formulation of the VB formalism. The adequacy of the proposed approach compared to classically used VB receivers is demonstrated by simulations.