Turbo equalization for doubly-selective MIMO fading channels using exponential basis models

We present an adaptive soft-input soft-output (SISO) turbo equalization receiver for doubly-selective multiple-input-multiple-output (MIMO) channels. The proposed receiver exploits the complex exponential basis expansion model (CE-BEM) for the overall channel variations, and an autoregressive (AR) model for the BEM coefficients. We extend an existing single-user turbo equalization approach based on symbol-wise AR modeling of channels to multiuser/MIMO channels based on BEMs. Simulation examples demonstrate that our CE-BEM-based approach has superior performance over a symbol-wise AR model-based turbo equalizer.