Energy-Efficient Symbol-Level Precoding in Multiuser MISO Based on Relaxed Detection Region

TL;DR

This paper introduces a novel energy-efficient symbol-level precoding method for multiuser MISO systems that leverages relaxed detection regions to enhance SINR and reduce transmit power, outperforming existing techniques.

Contribution

It proposes a generalized CI precoding design with relaxed detection regions and analyzes the tradeoff between power efficiency and SER, advancing multiuser interference management.

Findings

Proposed schemes outperform state-of-the-art techniques.

Relaxed detection regions improve energy efficiency.

Tradeoff analysis between SER and power reduction.

Abstract

This paper addresses the problem of exploiting interference among simultaneous multiuser transmissions in the downlink of multiple-antenna systems. Using symbol-level precoding, a new approach towards addressing the multiuser interference is discussed through jointly utilizing the channel state information (CSI) and data information (DI). The interference among the data streams is transformed under certain conditions to a useful signal that can improve the signal-to-interference noise ratio (SINR) of the downlink transmissions and as a result the system's energy efficiency. In this context, new constructive interference precoding techniques that tackle the transmit power minimization (min power) with individual SINR constraints at each user's receiver have been proposed. In this paper, we generalize the CI precoding design under the assumption that the received MPSK symbol can reside in a relaxed region in order to be correctly detected. Moreover, a weighted maximization of the minimum SNR among all users is studied taking into account the relaxed detection region. Symbol error rate analysis (SER) for the proposed precoding is discussed to characterize the tradeoff between transmit power reduction and SER increase due to the relaxation. Based on this tradeoff, the energy efficiency performance of the proposed technique is analyzed. Finally, extensive numerical results show that the proposed schemes outperform other state-of-the-art techniques.