MIMO uplink NOMA with successive bandwidth division

Non-orthogonal multiple access (NOMA) is a key enabling technology for fifth generation (5G) wireless networks because of its ability to provide greater spectral efficiency. However, a conventional NOMA scheme offers significant interference and higher outage probability especially when the number of users in the network is large. Therefore, in this paper, we propose a suboptimal algorithm which uses the concept of successive bandwidth division (SBD) in NOMA system, which not only reduces the complexity of the receiver side to a great extent, but also enhances the overall signal-to-interference plus noise ratio (SINR) of the uplink NOMA by supporting 2N users with just N base station (BS) antennas. The BS is assumed to have perfect channel state information (CSI) and uses a zero-forcing (ZF) postcoding matrix to recover the signals of different users. Numerical results show that the performance of the proposed scheme outperforms the conventional NOMA techniques in terms of receiver complexity and outage probability.