Abstract
This work presents a new framework that utilizes
power-domain (PD) nonorthogonal multiple access (NOMA) as a multiplexing
scheme to improve the throughput of point-to-point (P2P), or single
user, communications. The proposed framework synergizes PD-NOMA and
automatic repeat request (ARQ) to enable multiplexing and transmitting
multiple packets that belong to the same user simultaneously. To
overcome channel estimation and feedback limitations, and to reduce the
system complexity, a simple adaptation scheme is proposed select the
appropriate number packets to be transmitted within a given
transmission slot. Moreover, the number of transmitted packets
is limited to a maximum of two to allow the receiver to blindly
identify the number of transmitted packets in a particular
transmission slot. The obtained results show that the proposed
NOM scheme can eventually double the system throughput at
high signal-to-noise ratios (SNRs), and hence, reduce the delay
by 50%. The system complexity and overhead are generally
comparable to conventional ARQ systems.