Cooperative Non-orthogonal Multiple Access With Simultaneous Wireless Information and Power Transfer

TLDR

The paper investigates applying simultaneous wireless information and power transfer to non‑orthogonal multiple access networks with randomly located users. A cooperative SWIPT NOMA protocol is proposed in which nearby users harvest energy and relay to far users, and three distance‑based user selection schemes are introduced with closed‑form outage probability and throughput expressions. Analytical results show that SWIPT preserves diversity gain and that distance‑based user selection achieves lower outage probability and higher throughput than random selection.

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.