  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 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 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) a
power allocation stage for the BS THz-NOMA transmit power as well as the
cooperation power of the cooperating cell-center users, which is optimized in a
sequential manner. The obtained results quantify the EE of the proposed scheme
and shed new light on both the performance and design of multi-user
THz-NOMA-enabled networks.
