Avaliação de métodos para alocação de recursos em acesso múltiplo não ortogonal no domínio da potência.

Abstract

In recent years, the number of users of mobile communications services has grown signif- icantly, and there are predictions that this number will continue growing with the arrival

of the Internet of Things (IoT). In addition, new communications services are demand- ing ever-increasing data rates. However, the increase in the number of users and the data

rate is limited by the spectrum bandwidth available for these services. In this context, the Non Orthogonal Multiple Access (NOMA) technique presents itself as a strong candidate to promote spectrum sharing in next generation mobile communications systems (5G). The NOMA technique further exploits the power domain to multiplex users and increase the cell capacity region, taking advantage of the channel gain difference among users. The NOMA performance is conditioned by the choice of user pairs and individual transmission power levels. This work evaluates methods of user pairing and power allocation (UPPA) in the NOMA on downlink, seeking to increase spectral efficiency, and maintaining high fairness levels among users. In order to investigate the proposed methods performance, a system level simulator (SLS) is developed, which allows the evaluation of NOMA techniques in a multiuser environment. From the analysis developed, a fairness criterion based on the paired users SINR fraction is proposed. In compliance with this criterion, the calculation of the fair power allocation coefficient is derived. In addition, a user pairing strategy is used to balance the opportunities for gains among peers. The results of the simulations indicate

that the proposed method is better than Orthogonal Multiple Access and others resource al- location methods in NOMA, in terms of efficiency and fairness. It is also shown that NOMA

can be exploited to reduce the transmission power and interference generated.