Study of a Proposed Precoding Scheme for Multi-User MIMO-PD-NOMA Paradigm with Experimental Validation

The union of Multiple-Input-Multiple-Output (MIMO) with Non-Orthogonal Multiple Access (NOMA) scheme improves the effectiveness of the latter thereby boosting its spectral efficiency and robustness, while reducing latency. These features make MIMO-NOMA a more favourable option for beyond 5G networks, serving both broadband and machine-to-machine communication systems. Precoding is one of the major aspects of MIMO technology and a pivotal technique in wireless communication system that aims to uplift the overall system performance. Therefore, this paper proposes a new precoding technique, which is a modified version of Singular Value Decomposition (SVD) precoding, and hence, compares its performance with some of the prominent existing precoding schemes, in regard to power-domain NOMA (PD-NOMA), applying Constrained optimization Power Allocation (COPA) strategy, for a downlink network scenario. The performance of diverse precoding techniques, on a two-user MIMO-PD-NOMA (MIMO-NOMA) paradigm, are inspected on grounds of various modulation schemes, System Bit Error Rate (BER) and Sum Capacity, both on a simulation platform as well as on a Software Defined Radio (SDR) kit for experimental validation.