  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.
