Energy-Efficient Coverage Enhancement of Indoor THz-MISO Systems: An FD-NOMA Approach

TL;DR

This paper proposes an energy-efficient cooperative NOMA scheme for indoor THz-MISO systems, enhancing spectral efficiency and user fairness while ensuring minimum rates for cell-edge users in beyond 5G networks.

Contribution

It introduces a novel three-stage cooperative NOMA scheme with beamforming, user pairing, and power allocation tailored for indoor THz-MISO systems.

Findings

The scheme improves energy efficiency in indoor THz-NOMA networks.

Optimal power allocation enhances user fairness and system performance.

Results demonstrate significant gains over non-cooperative approaches.

Abstract

Terahertz (THz) communication is gaining more interest as one of the envisioned enablers of high-data-rate short-distance indoor applications in beyond 5G networks. Moreover, non-orthogonal multiple-access (NOMA)-enabled schemes are promising schemes to realize the target spectral efficiency, low latency, and user fairness requirements in future networks. In this paper, an energy-efficient cooperative NOMA (CNOMA) scheme that guarantees the minimum required rate for the cell-edge users in an indoor THz-MISO communications network is proposed. The proposed cooperative scheme consists of three stages: (i) beamforming stage that allocates base-station (BS) beams to THz cooperating cell-center users using analog beamforming with the aid of the cosine similarity metric, (ii) user pairing stage that is tackled using the Hungarian algorithm, and (iii) power allocation stage for both the BS THz-NOMA transmit power and the cooperation power of the cooperating cell-center users, which are optimized sequentially. The obtained results quantify the energy efficiency (EE) of the proposed scheme and shed new light on the performance of multi-user THz-NOMA-enabled networks.