  Sparse Code Multiple Access (SCMA) is one of the promising candidates for new
radio access interface. The new generation communication system is expected to
support massive user access with high capacity. However, there are numerous
problems and barriers to achieve optimal performance, e.g., the multiuser
interference and high power consumption. In this paper, we present optimization
methods to enhance the spectral and energy efficiency for SCMA with individual
rate requirements. The proposed method has shown a better network mapping
matrix based on power allocation and codebook assignment. Moreover, the
proposed method is compared with orthogonal frequency devision multiple access
(OFDMA) and code devision multiple access (CDMA) in terms of spectral
efficiency (SE) and energy efficiency (EE) respectively. Simulation results
show that SCMA performs better than OFDMA and CDMA both in SE and EE.
