Near-Field SWIPT Using XL-MIMO: Power Allocation and Subarray Activation

TL;DR

This paper explores power-efficient near-field SWIPT in XL-MIMO systems by optimizing power allocation and subarray activation to reduce power consumption while maintaining QoS for information and energy transfer.

Contribution

It introduces a joint optimization framework for power allocation and subarray activation in near-field XL-MIMO SWIPT systems, reducing power consumption significantly.

Findings

Power consumption reduced by over 60% compared to benchmark schemes.

Proposed algorithms effectively balance QoS and energy harvesting requirements.

Optimization achieves substantial efficiency improvements in near-field XL-MIMO SWIPT.

Abstract

This paper investigates the simultaneous wireless information and power transfer (SWIPT) capability of a modular extremely large multiple-input multiple-output (XL-MIMO) system, in the context of power consumption (PC) efficiency. The network users are divided into two functional categories: information decoding (ID) users and energy harvesting (EH) users. Non-stationary near-field channels are considered whilst the users are located in spatially distinct visibility regions (VRs). We formulate a two-tier joint optimization problem to minimize the PC, taking into account the power allocation (PA) for ID and EH users, along with the activation of constituent XL-MIMO subarrays. This complicated mixed-integer problem is transformed into more tractable formulations and efficient algorithms are proposed for solving them. The numerical results demonstrate that the overall PC of the XL-MIMO system for the proposed method is reduced by more than 60% in comparison to the benchmark scheme of equal PA with full subarray activation (SA) and 30% against the case of optimized PA with full SA, while satisfying the quality-of-service (QoS) constraints on both the downlink rate of the ID users and harvested energy at the EH users.