OFDM-MIMO communication systems in a Rayleigh faded environment with imperfect channel estimates

This paper presents the performance of mobile orthogonal frequency division multiplexing (OFDM) multiple-input multiple-output (MIMO) communication systems with imperfect knowledge of the channel matrix. MIMO systems typically require a channel matrix, which can be determined initially from a training sequence. However, mobile communication systems exhibit a time-varying channel matrix and have time and frequency selective fades which result in performance degradation of the MlMO system. Channel tracking methods can be used to estimate the time-varying channel matrix but cannot in practice be error free. This paper presents results of V-BLAST (vertical Bell Laboratories layered space-time) MlMO simulations using the geometric wideband time-varying channel model (GWTCM) with Rayleigh faded environments and imperfect channel matrix knowledge. Flat fading is assumed for each OFDM subcarrier. OFDM-MIMO architectures such as OFDM coupled with V-BLAST can be easily implemented by exploiting the built-in and flexible multi-channel architectures of advanced software defined radios (SDR).