On the Performance of Non-Orthogonal Multiple Access in 5G Systems with Randomly Deployed Users

In this letter, the performance of non-orthogonal multiple access (NOMA) is investigated in a cellular downlink scenario with randomly deployed users. The developed analytical results show that NOMA can achieve superior performance in terms of ergodic sum rates; however, the outage performance of NOMA depends critically on the choices of the users´ targeted data rates and allocated power. In particular, a wrong choice of the targeted data rates and allocated power can lead to a situation in which the user´s outage probability is always one, i.e. the user´s targeted quality of service will never be met.