Outage Probability analysis of Power Domain MISO-NOMA in Rayleigh Fading Channel

The multiple access technique of the current wireless communication system depends on the orthogonal multiple access (OMA) technique. The availability of orthogonal resources is limited in OMA and cannot support the increasing demand for a large number of users and efficient use of the spectrum in the coming years. The Non-orthogonal multiple access (NOMA) is considered in the future release of 5G and beyond 5G. In NOMA, multiple users can be dealt with in the same resource block at the same time, which allows NOMA to provide large connectivity, low latency, and high spectral efficiency. In this paper, the outage probability expression for the MISO-NOMA downlink system is derived by employing an indefinite quadratic form (IQF) approach. Analytical results are compared with the Monte Carlo simulations which validate our theoretical derivations. Further, the performance of the MISO-NOMA system is assessed with different numbers of users in the system and different SNR values.