A Sparse Superposition Multiple Access Scheme and Performance Analysis for 5G Wireless Communication Systems

Orthogonal multiple access (OMA) is widely employed in traditional cellular wireless communication systems due to a low-complexity receiver is needed. However, multiple access scheme with higher spectral efficiency and the capability of access more users than OMA scheme is preferred for the future wireless communication systems. In this work, we propose a non-orthogonal multiple access scheme called sparse superposition multiple access (SSMA) by superposing more users to a limited number of time-frequency resource for the uplink transmission in the fifth generation (5G) wireless communication systems. Moreover, we design two sparse superposition matrices (SSMs) for 150% and 200% overloaded SSMA scheme. Then, a low complexity belief propagation detection and decoding algorithm based multiple user detection is proposed. Furthermore, we utilize extrinsic information transfer chart to analyze the superiority of the proposed SSMs theoretically and the numerical results show that the proposed SSM with an overload of 150% has a gain of about 1 dB compared to the existing scheme. Finally, simulation results demonstrate that the proposed scheme outperforms the traditional OMA scheme and the existing scheme significantly.