Performance Comparison of NOCA and IDMA for 5G Multiple Access

In 5G systems, one use case is massive machinetype communications (mMTC) where a large number of devices are required to be supported. The mMTC devices are of low cost and low complexity with limited energy. They often have sporadic traffic and small packets to transmit which requires low signaling overhead. For this reason, contention-based multiple access protocols are attractive candidates. However, collisions might occur in the contention-based access techniques. Therefore, the combination of appropriate multi-user detection strategies in conjunction with multiple access schemes is highly necessary. Superposition-based non-orthogonal multiple access (NOMA) techniques have been proposed for 5G to satisfy the requirements of mMTC. In this paper, we compare the performance of two NOMA techniques based on superposition, such as interleavedivision multiple access (IDMA) and non-orthogonal coded access(NOCA) in terms of bit error rate in a multi-user scenario.