ABSTRACT
Non orthogonal multiple access (NOMA), which has the ability to handle as much data as 5G networks, is a spectrum-efficient alternative. Nevertheless, classical orthogonal access algorithms such as time divisional orthogonal, frequency division, and code division multiple accesses, can simply share the same (frequency, time, and code) resource block with non-orthogonal multiple access. Furthermore, by superimposing signals of the users and sequential interference cancellation (SIC) use at the receiver’s end, this can also be achieved. During the process, the strongest user decodes the weaker one’s signal first and decodes itself afterwards. To give it a higher rate during delivering near optimal performance to the weaker user, the strongest user requires a very small amount of power. In addition, several combined NOMA-aided beamforming multiple-input multiple-output (MIMO) methods have recently been presented, motivated by the higher spectral efficiency given by NOMA. However, design of efficient combined schemes will encounter several challenges including power allocations, users’ coordination, and users’ clustering/selection. For example, a joint user selection with optimized beamforming scheme was proposed for mm wave communication.
