Joint Beamforming Design for Multi-User Wireless Information and Power Transfer

TL;DR

This paper introduces a joint beamforming algorithm for multi-user wireless information and power transfer systems, enhancing energy harvesting while managing SINR constraints, validated through simulations and analysis.

Contribution

It proposes a novel joint beamforming method that optimizes energy harvesting and SINR in MU-WIPT systems, extending MU-MIMO techniques with new analysis under perfect and imperfect CSIT.

Findings

Increased harvested energy at the cost of SINR loss for ID users.

The proposed algorithm outperforms conventional schemes in simulations.

Analysis of sum rate and energy harvesting under different CSIT conditions.

Abstract

In this paper, we propose a joint beamforming algorithm for a multiuser wireless information and power transfer (MU-WIPT) system that is compatible with the conventional multiuser multiple input multiple output (MU-MIMO) system. The proposed joint beamforming vectors are initialized using the well established MU-MIMO zero-forcing beamforming (ZFBF) and are further updated to maximize the total harvested energy of energy harvesting (EH) users and guarantee the signal to interference plus noise ratio (SINR) constraints of the co-scheduled information decoding (ID) users. When ID and EH users are simultaneously served by joint beamforming vectors, the harvested energy can be increased at the cost of an SINR loss for ID users. To characterize the SINR loss, the target SINR ratio,u, is introduced as the target SINR (i.e., SINR constraint) normalized by the received SINR achievable with ZFBF. Based on that ratio, the sum rate and harvested energy obtained from the proposed algorithm are analyzed under perfect/imperfect channel state information at the transmitter (CSIT). Through simulations and numerical results, we validate the derived analyses and demonstrate the EH and ID performance compared to both state of the art and conventional schemes.