Enhancing the Performance of MIMO-NOMA Systems Based on Peak to Peak Data Rate Difference

In 5G wireless communication systems, Non-orthogonal multiple access (NOMA) is a technique for improving the spectral-efficiency (SE) of the systems by supporting massive wireless mobile devices. NOMA solved the problem of additional power consumption and bandwidth by utilizing user pairing techniques. In this paper, a capacity-based user-pairing techniques for power domain downlink NOMA are introduced, namely, peak to peak data rate difference (P2PDRD) user pairing technique. The P2PDRD user pairing technique depends on the users' individual capacity in such a way to select which ones can be paired together to maximize the SE of the system. The proposed algorithm's performance is compared to that of other traditional algorithms. which are based on channel gain difference. According to the numerical analysis, an increase in the number of antennas from
$2\times 2$
to
$16\times 16$
raises the SE of the system from 6.47 bps/Hz to 128.7 bps/Hz. Finally, the proposed P2PDRD Algorithm was shown to improve the total sum rate and maximize the system's SE.