Performance of High Mobility MIMO Communications with Doppler Diversity

Rapid change of the channels in high-speed mobile communications will lead to difficulties in channel estimation and tracking, but can also provide Doppler diversity. In this paper, the performance of multiple-input multiple-output system with pilot-assisted repetitive coding and spatial multiplexing has been studied. With minimum mean square error (MMSE) channel estimation, an equivalent channel model and the corresponding system model are presented. Based on the random matrix theory, the asymptotic expressions of the normalized achievable sum rate of linear receivers, such as maximal ratio combining (MRC) receiver, MMSE detection and MRC-like receiver are derived. In addition, according to the symbol error rate of the MRC-like receiver, the maximum normalized Doppler diversity order, the minimum coding gain loss can be achieved when the repetition number and the signal to noise ratio tend to infinity and corresponding conditions are also derived. Based on the theoretical results, the impacts of different system configurations and channel parameters on system performance have been demonstrated.