Jointly Broadcasting Data and Power with Quality of Service Guarantees

TL;DR

This paper analyzes a wireless broadcast system where an energy harvesting transmitter communicates with multiple receivers, ensuring quality of service while optimizing energy and data transfer through different receiver architectures.

Contribution

It characterizes the fundamental limits of joint data and power transmission with QoS guarantees for ideal, time-switching, and power-splitting receivers, revealing their relative efficiencies.

Findings

Time-switching receivers can switch modes without rate loss or transmitter knowledge.

Power-splitting receivers support higher data rates than time-switching for the same power.

The study provides fundamental limits for joint information and energy transfer in fading Gaussian broadcast channels.

Abstract

In this work, we consider a scenario wherein an energy harvesting wireless radio equipment sends information to multiple receivers alongside powering them. In addition to harvesting the incoming radio frequency (RF) energy, the receivers also harvest energy from {its environment (e.g., solar energy)}. This communication framework is captured by a fading Gaussian Broadcast Channel (GBC) with energy harvesting transmitter and receivers. In order to ensure {some quality of service (QoS)} in data reception among the receivers, we impose a \textit{minimum-rate} requirement on data transmission. For the setting in place, we characterize the fundamental limits in jointly transmitting information and power subject to a QoS guarantee, for three cardinal receiver structures namely, \textit{ideal}, \textit{time-switching} and \textit{power-splitting}. We show that a time-switching receiver can {switch} between {information reception mode} and {energy harvesting mode}, \textit{without} the transmitter's knowledge of the same and \textit{without} any extra \textit{rate loss}. We also prove that, for the same amount of power transferred, on average, a power-splitting receiver supports higher data rates compared to a time-switching receiver.