A LARGE-SCALE EXTENSION OF SPARSE-CODE MULTIPLE-ACCESS SYSTEM

Sparse-code multiple-access (SCMA) is an effective non-orthogonal multiple-access (NOMA) technique, which ranks one of the most promising candidates for future wireless, because of its outstanding performance. However, most of the existing work prefers low-connectivity SCMA systems, which actually cannot fulfill their priorities for massive connection. The difficulties in designing suitable factor graph matrix are responsible for this situation. In this paper, we propose a design manner of factor graph matrix to realize SCMA with large-scale customers. Quasi-cyclic property with shifting is introduced in SCMA factor graph matrix, based on the rules and restrictions of SCMA design including the column weight and the overloading factor. For numerical analysis, we introduce a performance function to show the effectiveness of our proposed SCMA system, and the results reveal that our work are better than conventional ones.