Throughput Maximization for Wireless Powered Communications Harvesting from Non-dedicated Sources

TL;DR

This paper optimizes the energy harvesting and transmission protocol in wireless powered communications to maximize throughput, considering direct and relay transmission modes under outage constraints.

Contribution

It derives the optimal harvesting ratio for both direct transmission and relay modes, revealing different dominant factors affecting each.

Findings

Optimal harvest ratio for direct transmission is outage constraint dominated.

Optimal harvest ratio for relay is data causality dominated.

Maximized throughput under outage constraints.

Abstract

We consider the wireless powered communications where users harvest energy from non-dedicated sources. The user follows a harvest-then-transmit protocol: in first phase of a slot time the source node harvests energy from a nearby conventional Access Point, then transmit information to its destination node or relay node in the second phase. We obtain the optimal\textit{ harvesting ratio} to maximize the expected throughput for direct transmission (DT )and decode forward (DF) relay under outage constraint, respectively. Our results reveal that the optimal harvest ratio for DT is dominated by the outage constraint while for DF relay, by the data causality .