Non-orthogonal multiple access (NOMA): Concept, performance evaluation and experimental trials

Non-orthogonal multiple access (NOMA) has been attracting a lot of attention as a promising downlink multiple access scheme for LTE enhancements and 5G. This paper introduces an overview of the concept, performance evaluation gains and our experimental trials related to NOMA. The goal is to clarify the benefits of NOMA over orthogonal multiple access (OMA) such as OFDMA adopted by Long-Term Evolution (LTE), also its combination with MIMO is discussed. Using computer simulations, NOMA performance gains are assessed from both link-level and system-level perspectives. Also, our NOMA test-bed and the measurement results are explained. Our evaluation results and measurements show that NOMA provides higher gains compared to OFDMA. These gains are more than 30%.