A novel hybrid spreading and scrambling based multiple access (SSMA) technique for capacity improvement

Future wireless networks and 5G communication technology aims to provide seamless connectivity for geographical areas having thousands of users within hundreds of meter radius. Emerging communication technologies, specifically, multiple access techniques have to provide enhanced capacity in order to meet this objective. power domain non-orthogonal multiple access (PD-NOMA), which is a prominent multiple access technique for 5G, fails to distinguish equidistant users around base station on the basis of power factors. To overcome this limitation and to further improve the capacity, a novel hybrid spreading and scrambling based multiple access (SSMA) technique is proposed in this paper. The proposed scheme combines power domain NOMA and multiuser shared access (MUSA). The main objective is to provide improved capacity and better performance without compromising spectral efficiency and non-orthogonality of the resources. One of the major contributions of this paper is the development of joint interference cancellation algorithm combining both successive interference cancellation and parallel interference cancellation for the proposed SSMA system. The performance of the proposed scheme is analyzed and compared with MUSA and PD-NOMA to show its superiority over both, in terms of BER, capacity, and spectral efficiency.