Performance improvement of non-orthogonal multiple access scheme using code division multiplexing

Currently, the standardization of fifth-generation mobile communication system (5G), which realizes 10 Gbps transmission, is in progress. In mobile communications, it is generally difficult to perform high-capacity transmission because of channel fading. Therefore, an adaptive resource allocation scheme based on users’ channel conditions is adopted to enhance the system capacity. Recently, it has been shown that a non-orthogonal multiple access scheme can achieve a higher system capacity than orthogonal multiple access scheme. However, anticipating a continuous increase in mobile traffic, it is desired to further enhance the throughput of non-orthogonal multiple access scheme. Therefore, we propose an application of code division multiplexing to non-orthogonal multiple access scheme using successive interference canceler to improve the throughput performance. The improved performance is demonstrated through numerical simulations.