As a candidate non-orthogonal multiple access technology for 5G, the sparse code multiple access (SCMA) can effectively improve spectrum efficiency. In this paper, the layered multicast scheme in SCMA network was first studied, of which the system capacity is not limited by the worst channel quality user in the multicast group. Specifically, a network energy efficiency (EE) maximization problem subject to quality of service (QoS) requirements, codebook assignment, and power allocation was formulated. In order to reduce the computational complexity, a fast sub-optimization algorithm (FSA) by separating codebook assignment and power allocation was then proposed. Finally, the simulation results verified the network EE of the proposed algorithm significantly outperforms conventional multicast (CM) scheme in SCMA systems and orthogonal frequency division multiple access (OFDMA) systems. Moreover, the performance of SCMA systems with FSA is better than the performance of OFDMA systems with FSA.
