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.
@article{arxiv.1406.1516,
title = {On the Performance of Non-Orthogonal Multiple Access in 5G Systems with Randomly Deployed Users},
author = {Zhiguo Ding and Zheng Yang and Pingzhi Fan and H. Vincent Poor},
journal= {arXiv preprint arXiv:1406.1516},
year = {2015}
}