A flexible resource scheduling scheme for an adaptive SCMA system

Sparse code multiple access (SCMA) is a new type of non-orthogonal multiple access technology, and it originates from low-density signature (LDS) technology. SCMA can obtain an additional coding gain through the codebook design. Combining the concepts of OFDMA and CDMA, SCMA has the advantages of high capacity, low time delay and high data rate. We propose adaptive allocation technology (AAT) and design an adaptive SCMA system. The designed system has better flexibility and adaptability than conventional OFDMA and SCMA systems. However, preventing fragmentation of physical resource blocks (PRBs) in the resource scheduling is crucial for rendering the adaptive SCMA system feasible. For this purpose, we design two optional resource scheduling schemes: resource first and user first. The theoretical derivation and simulation results demonstrate the feasibility and superiority of the proposed algorithms and schemes in terms of system throughput and packet loss rate (PLR) performance.