On the number of users served in MIMO-NOMA cellular networks

Envisioned to be a component of 5G cellular networks, non-orthogonal multiple access (NOMA) can accommodate more users and has superior spectral efficiency compared to the conventional orthogonal multiple access schemes. NOMA, however, intensifies inter-cell interference since its power allocation strategy is biased toward cell-edge users. To deal with this problem in a multi-cell multiple-input multiple-output (MIMO) communication network, a new interfering channel alignment based NOMA technique is developed in this paper. The maximum number of users supported by the proposed scheme in multi-cell MIMO networks is characterized for any given system parameter values such as the number of transmit and receive antennas and the number of cells.