Charge-then-Forward: Wireless Powered Communication for Multiuser Relay Networks

TL;DR

This paper proposes a relay-assisted wireless powered communication network with a charge-then-forward protocol, optimizing resource allocation to maximize sum-rate, and introduces solutions for both TDMA and FDMA schemes validated by simulations.

Contribution

It introduces a novel charge-then-forward protocol for multiuser relay networks and develops optimal and suboptimal resource allocation algorithms for TDMA and FDMA.

Findings

Optimal solutions for TDMA and FDMA schemes are derived.

Suboptimal algorithms effectively balance complexity and performance.

Simulation results confirm the effectiveness of the proposed methods.

Abstract

This paper studies a relay-assisted wireless powered communication network (R-WPCN) consisting of multiple source-destination pairs and a hybrid relay node (HRN). We consider a "charge-then-forward" protocol at the HRN, in which the HRN with constant energy supply first acts as an energy transmitter to charge the sources, and then forwards the information from the sources to their destinations through time division multiple access (TDMA) or frequency division multiple access (FDMA). Processing costs at the wireless-powered sources are taken into account. Our goal is to maximize the sum-rate of all transmission pairs by jointly optimizing the time, frequency and power resources. The formulated optimization problems for both TDMA and FDMA are non-convex. For the TDMA scheme, by appropriate transformation, the problem is reformulated as a convex problem and be optimally solved. For the FDMA case, we find the asymptotically optimal solution in the dual domain. Furthermore, suboptimal algorithms are proposed for both schemes to tradeoff the complexity and performance. Finally, the simulation results validate the effectiveness of the proposed schemes.