PH-NOMA with PBPA/IBPA realizes the best performance.
It is also worth noting that the performance gap between all
the NOMA-based multi-user beamforming and conventional
ZFBF algorithms diminishes as N becomes large. In Fig. 4,
the sum rate performance versus SNR is shown. It is observed
that the proposed PH-NOMA with PBPA/IBPA scheme has
about 2.1dB gain compared to conventional ZFBF, while
the PH-NOMA with other user pairing algorithms only have
limited performance gain.
In Fig. 5, the outage performance is illustrated as a
function of SNR for different user pairing algorithms.
It can be observed that the proposed beamforming algorithms
(PH-NOMA beamforming in combination with PBPA/IBPA)
have a significant improvement compared to conventional
ZFBF, while other user pairing algorithms only have limited
VOLUME 4, 2016 4