SU-MIMO based uplink non-orthogonal multiple access for 5G

Abstract

In this paper, we present the application of single user multiple input multiple output (SU-MIMO) to uplink (UL) non-orthogonal multiple access (NOMA) to enhance UL capacity. However, SU-MIMO NOMA produces inter stream interference in addition to intra-pair interference, leading to performance degradation. Therefore, a novel UL SU-MIMO NOMA signal detection, combining minimum mean square error (MMSE) with dual-level iterative successive interference cancelation is proposed to mitigate the interference. Additionally, generalized dynamic power allocation is proposed at UL transmitters to ensure the capacity for NOMA over orthogonal multiple access (OMA) and the capability to overcome error floor phenomenon caused by fixed power allocation. A practical SIC scheme is also considered to create a more realistic scenario than the perfect SIC. The proposed system is evaluated in terms of capacity, throughput, error performance, and computational complexity. The results show that the proposed SU-MIMO based NOMA outperforms in capacity, throughput, and error performance at the same MMSE complexity order.