Improved Linear Transmit Processing for Single-User and Multi-User MIMO Communications Systems

Abstract

Abstract-In this paper, we propose a novel linear transmit precoding strategy for multiple-input, multiple-output (MIMO) systems employing improper signal constellations. In particular, improved zero-forcing (ZF) and minimum mean square error (MMSE) precoders are derived based on modified cost functions, and are shown to achieve a superior performance without loss of spectrum efficiency compared to the conventional linear and non-linear precoders. The superiority of the proposed precoders over the conventional solutions are verified by both simulation and analytical results. The novel approach to precoding design is also applied to the case of an imperfect channel estimate with a known error covariance as well as to the multi-user scenario where precoding based on the nullspace of channel transmission matrix is employed to decouple multi-user channels. In both cases, the improved precoding schemes yield significant performance gain compared to the conventional counterparts.

Transceiver design for SU-MIMO system with improper modulations using per antenna power constraint and perfect CSI

“…The newly proposed p norm constraint jointly meets both the per-antenna power constraint (PAPC) and the Sum Ppower Constraint(SPC) to bound the dynamic range of the power amplifier at each transmit antenna [6]. The improved minimum TMSE design for improper signal constellations was recently proposed in [7] and shown to give superior BER performance than the conventional design in [8]. A Transceiver is designed with Improper modulations using SPC in [9] and Joint optimum precoder and decoder is designed using per antenna constraint in [10].However, to the best of our knowledge, no attention has been paid to the optimum joint linear transceiver design for the SU-MIMO systems which employ one dimensional improper modulation techniques that minimize the sum of symbol estimation errors subject to both sum and individual power constraint, with the perfect CSI at both the transmitter and the receiver.…”