Power Loss Reduction for MMSE-THP With Multidimensional Symbol Scaling

This letter presents a strategy to reduce the power consumption of the Tomlinson–Harashima precoder (THP) based on the minimum mean square error (MMSE) criterion for the multi-user transmission. We show that a significant power loss reduction can be obtained by optimizing the interference to be cancelled by THP, using appropriate scaling of the interfering symbols. We advance the state of the art, by adopting a multidimensional optimization across a number of users and further modifying this optimization to apply to MMSE-THP, where it was previously inapplicable. By use of these improvements, the proposed approach is able to maintain or increase the error performance of MMSE-THP while providing up to 50% reduction in the power consumption.