Objective:
In this paper, Decode-and-Forward (DF) mode is deployed in the Relay Selection
(RS) scheme to provide better performance in cooperative downlink Non-orthogonal Multiple
Access (NOMA) networks. In particular, evaluation regarding the impact of the number of multiple
relays on outage performance is presented.
Methods:
As main parameter affecting cooperative NOMA performance, we consider the scenario of
the fixed power allocations and the varying number of relays. In addition, the expressions of outage
probabilities are the main metric to examine separated NOMA users. By matching related results between
simulation and analytical methods, the exactness of derived formula can be verified.
Results:
The intuitive main results show that in such cooperative NOMA networks, the higher the
number of relays equipped, the better the system performance can be achieved.
Conclusion:
DF mode is confirmed as a reasonable selection scheme to improve the transmission quality
in NOMA. In future work, we will introduce new relay selections to achieve improved performance.
Relay selection scheme for AF system with partial CSI and optimal stopping theory
