Improved Performance of RF Energy Powered Wireless Sensor Node with Cooperative Beam Selection

TL;DR

This paper proposes a cooperative beam selection scheme for multiuser MIMO systems to enhance RF energy harvesting at wireless sensor nodes, balancing energy collection and data transmission performance.

Contribution

It introduces a novel random unitary beamforming scheme that optimizes energy harvesting while maintaining system data rates under power constraints.

Findings

Closed-form expression for harvested energy distribution

Tradeoff analysis between energy harvesting and sum-rate

Enhanced energy harvesting performance with beam selection

Abstract

RF energy harvesting is a promising potential solution to provide convenient and perpetual energy supplies to low-power wireless sensor networks. In this paper, we investigate the energy harvesting performance of a wireless sensor node powered by harvesting RF energy from existing multiuser MIMO system. Specifically, we propose a random unitary beamforming (RUB) based cooperative beam selection scheme to enhance the energy harvesting performance at the sensor. Under a constant total transmission power constraint, the multiuser MIMO system tries to select a maximal number of active beams for data transmission, while satisfying the energy harvesting requirement at the sensor. We derive the exact closed-form expression for the distribution function of harvested energy in a coherence time over Rayleigh fading channels. We further investigate the performance tradeoff of the average harvested energy at the sensor versus the sum-rate of the multiuser MIMO system.