Rate Maximization of Decode-and-Forward Relaying Systems with RF Energy Harvesting

TL;DR

This paper investigates optimizing data rate in a relay system where the source harvests RF energy from the relay, proposing schemes for joint power and time fraction allocation to enhance performance.

Contribution

It introduces two schemes for optimal power and time fraction allocation in RF energy harvesting relay systems, improving data rates over fixed allocation methods.

Findings

Jointly optimal power and TF allocation outperforms fixed schemes.

Both proposed schemes significantly outperform fixed allocation benchmarks.

Harvested power is small, leading to similar performance between the two schemes.

Abstract

We consider a three-node decode-and-forward (DF) half-duplex relaying system, where the source first harvests RF energy from the relay, and then uses this energy to transmit information to the destination via the relay. We assume that the information transfer and wireless power transfer phases alternate over time in the same frequency band, and their {\it time fraction} (TF) may change or be fixed from one transmission epoch (fading state) to the next. For this system, we maximize the achievable average data rate. Thereby, we propose two schemes: (1) jointly optimal power and TF allocation, and (2) optimal power allocation with fixed TF. Due to the small amounts of harvested power at the source, the two schemes achieve similar information rates, but yield significant performance gains compared to a benchmark system with fixed power and fixed TF allocation.