Análise de sistema mimo-noma cooperativo com seleção de antena e retransmissão df

Abstract

Some of the main challenges faced by future generation mobile networks is the improvement of spectral efficiency and massive connectivity, required by the growing demand for mobile internet and internet of things (IoT). These requirements are difficult to meet with conventional orthogonal multiple access schemes. Non-orthogonal multiple access (NOMA) emerged as a promising multiple access scheme to further improve efficiency in the use of the spectrum, accommodating more users through the allocation of non-orthogonal resources. In this dissertation, comprehensive research is presented on the main theories of NOMA for future generations of mobile networks. In addition, an analysis of the performance of a cooperative NOMA system with multiple antennas is carried out for the transmission and reception of information. In particular, a base station uses the overlay encoding technique to communicate simultaneously with a pair of users through the collaboration of a decode-and-forward relay. The transmitting antenna selection scheme and the selection combination technique are employed at the base station and the users, respectively. Closed form expressions for the outage probability are obtained and, through them, an asymptotic analysis is performed. Numerical simulations are presented in order to investigate the effect of the number of antennas, power allocation coefficients, as well as the distance between the terminals and the analysis of the data rate on the systemic performance, to validate the analytical results. NOMA network inspired by cognitive radio is also studied, in which the QoS of the user with the worst channel conditions is guaranteed. The outage probability of the secondary user is analyzed and simulation results are performed to corroborate the theoretical analyzes. The results demonstrate the superiority of NOMA in relation to the different scenarios proposed.