Time-selective channel estimation in two-way multi-relay MIMO-OFDM transmissions

This paper is concerned with doubly selective channel estimation for two-way multi-relay orthogonal frequency division multiplexing (OFDM) transmissions with multiple-input multiple-output (MIMO) configurations. Over time-varying cascaded fading channels among moving nodes, basis expansion models (BEMs) are deployed as fitting parametric models to reduce the number of channel parameters to be estimated. Using maximum likelihood (ML) estimation principle, BEM coefficients are first estimated then time-varying cascaded channel responses are determined by replacing the estimated BEM coefficient values into the used BEM expression. Simulation results are provided to verify the performance of the proposed estimation algorithm under different system scenarios.