Cooperative Non-Orthogonal Multiple Access with Simultaneous Wireless Information and Power Transfer

TL;DR

This paper explores a cooperative SWIPT NOMA protocol where near users harvest energy to assist far users, with user selection based on location improving outage probability and throughput.

Contribution

It introduces a novel cooperative SWIPT NOMA protocol with location-based user selection schemes and derives analytical performance metrics.

Findings

SWIPT does not reduce diversity gain compared to traditional NOMA.

Location-based user selection improves outage probability.

Opportunistic user selection achieves higher throughput.

Abstract

In this paper, the application of simultaneous wireless information and power transfer (SWIPT) to non-orthogonal multiple access (NOMA) networks in which users are spatially randomly located is investigated. A new cooperative SWIPT NOMA protocol is proposed, in which near NOMA users that are close to the source act as energy harvesting relays to help far NOMA users. Since the locations of users have a significant impact on the performance, three user selection schemes based on the user distances from the base station are proposed. To characterize the performance of the proposed selection schemes, closed-form expressions for the outage probability and system throughput are derived. These analytical results demonstrate that the use of SWIPT will not jeopardize the diversity gain compared to the conventional NOMA. The proposed results confirm that the opportunistic use of node locations for user selection can achieve low outage probability and deliver superior throughput in comparison to the random selection scheme.