Multiple-access Fading Channel with Wireless Power Transfer and Energy Harvesting

TL;DR

This paper analyzes the achievable rates in a multiple-access fading channel with wireless power transfer, optimizing power and rate allocations for energy-harvesting users to maximize the rate region.

Contribution

It derives the optimal power and rate allocation strategies for a multiple-access channel with wireless energy transfer, applicable to both infinite and finite battery and slot scenarios.

Findings

Optimal power allocation for the base station and users is derived.

The online solution is asymptotically optimal for large systems.

The approach is applicable to finite battery capacities and transmission slots.

Abstract

We consider the achievable average rates of a multiple-access system, which consists of N energy-harvesting users (EHUs) that transmit information over a block fading multiple-access channel (MAC) and a base station (BS) that broadcasts radio frequency (RF) energy to the EHUs for wireless power transfer. The information (over the uplink) and power (over the downlink) can be transmitted either in time division duplex or frequency division duplex. For the case when the EHUs battery capacities and the number of transmission slots are both infinite, we determine the optimal power allocation for the BS and the optimal rates and power allocations for the EHUs that maximize the achievable rate region of the MAC. The resulting online solution is asymptotically optimal, and also applicable for a finite number of transmission slots and finite battery capacities.