On the Performance of IDMA-Based Non-Orthogonal Multiple Access Schemes

Non-orthogonal multiple access (NOMA) is an important part of the emerging fifth generation (5G) of mobile communications systems. NOMA schemes based on a long spreading mechanism, such as interleave division multiple access (IDMA), are among the main candidates for potential use in 5G. Interleave-based NOMA methods can provide a robust performance in highly interfered environments. In this paper, we present our performance evaluation results for IDMA and its simplified variants, namely, resource spreading multiple access (RSMA) and RSMA with interference cancellation (RSMA-SIC). In our evaluation, various interference scenarios, fading conditions and channel estimation errors are considered. Our results indicate that while IDMA offers the best performance, RSMA and RSMA-SIC may also maintain a respectable level of performance with a lower complexity.