This paper proposes a novel hybrid downlinkuplink cooperative NOMA
(HDU-CNOMA) scheme to achieve a better tradeoff between spectral efficiency and
signal reception reliability than the conventional cooperative NOMA schemes. In
particular, the proposed scheme enables the strong user to perform a
cooperative transmission and an interference-free uplink transmission
simultaneously during the cooperative phase, at the expense of a slightly
decrease in signal reception reliability at the weak user. We analyze the
outage probability, diversity order, and outage throughput of the proposed
scheme. Simulation results not only confirm the accuracy of the developed
analytical results, but also unveil the spectral efficiency gains achieved by
the proposed scheme over a baseline cooperative NOMA scheme and a
non-cooperative NOMA scheme.Comment: 7 pages, accepted for presentation at the IEEE VTC 2017 Spring,
Sydney, Australi