Linear Precoded THP-FDE for Single-Carrier Broadband MIMO Systems

Abstract

Tomlinson–Harashima precoding with frequency-domain equalization (THP-FDE) is a promising approach for multiple-input multiple-output (MIMO) single-carrier broadband systems. By performing interference cancelation at the transmitter, THP-FDE performs better than frequency-domain decision-feedback equalization (FD-DFE) via eliminating the error propagation problem resulting from incorrect symbol decisions. One of the drawbacks for MIMO THP-FDE systems is that the spatial stream with the largest mean square error (MSE) dominates the error performance. To alleviate this problem, conventional design adopts a sorting algorithm (a permutation matrix) to minimize the worst-case stream MSE. Since the difference of stream MSEs roots in the nonequal diagonal entries of the MSE matrix in the time domain, we are motivated to apply a general linear precoder based on geometric-mean decomposition to balance these MSEs. By jointly optimizing the precoder and equalizer, we are able to minimize the arithmetic MSE, geometric MSE, and the worst stream MSE simultaneously for the MIMO THP-FDE system. Simulation results are presented to demonstrate the superior bit-error-rate (BER) performance of the proposed transceiver architecture for MIMO THP-FDE systems.