MIMO precoders using spatial and path correlations for multipath fading channels

This paper presents MIMO precoder designs for frequency-selective channels based on the transmit, receive and channel path correlation matrices. Optimal linear precoder structures are derived based on ergodic capacity criterion for three different scenarios: uncorrelated channel paths but equal spatial correlation matrices, uncorrelated channel paths but unequal spatial correlation matrices, and correlated channel paths. For channels with uncorrelated paths, the precoding structure is composed of a number of parallel precoders designed for frequency-flat fading channels. Simulation results show that the proposed precoders outperform others based only on spatial correlation in various propagation scenarios. Their achievable capacity is better in highly correlated (either spatial or path correlation) environments.