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Growing and expanding the use of cellular networks nowadays has led to the emergence of creating new generations of telecommunication networks.The race for developing 5G technology has taken a multi organizational competition in the recent past,where the professional bodies,private organizations,and research units are carrying out research in developing various technologies relating to 5G.It consists of high-pitch upload rate for audio and video packs,wide network dimensions,high-level access codes to codebooks and so on.Higher demands are placed on wireless communication technologies in terms of user experience rates,mass linkages,latency and reliability and better Quality of Service（QoS）,which require industry and academia to explore a host of new key points technology to meet the expectations.In many key technology exploration,it is crucial to design a new air interface to satisfy the requirements of 5G for massive links.Sparse code multiple access（SCMA）is a typical example.It is undoubtedly 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.SCMA can set the number of subcarriers to access the system and the number of non-zero elements in the codebook according to the specific situation.However,SCMA requires more sophisticated multi-user detection algorithms compared to OFDMA（Orthogonal Frequency Division Multiple Access）.This thesis mainly focuses on power allocation and energy efficiency in SCMA system.· We present optimization methods to enhance the spectral and energy efficiency for SCMA with individual rate requirements resource allocation algorithms for uplink sparse code multiple access（SCMA）networks to maximize the energy efficiency（EE）.The proposed method has shown a better network mapping matrix based on power allocation and codebook assignment.Moreover,the proposed method is compared with orthog-onal frequency division multiple access（OFDMA）and code division 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.· We propose resource allocation algorithms for uplink sparse code multiple access（SCMA）networks to maximize the energy efficiency（EE）.The EE optimization problem due to the product between factor graph matrix and power allocation matrix and also the constraints are combinational factor graph matrix,indicates to be non-convex mixedinteger non-linear program（MINLP）problem.After transforming the non-convex form of the uplink sum rate to a convex one and separating subcarrier assignment and power allocation,we first propose an energy efficient subcarrier assignment algorithm.Then by applying the fractional programming theory based on Dinkelbach method,we propose power allocation algorithm to maximize EE optimization problem.Finally,the simulation results show that the proposed resource allocation algorithm can significantly increase the EE of the uplink SCMA network.This thesis shows the effectiveness of the proposed algorithms to maximize the EE for an uplink SCMA system,where the the path losses between each user and the base station（BS）are not necessarily equal.The mathematical model of optimal uplink resource allocation is established where the features of SCMA are well characterized and we formulate EE problem based on factor graph matrix.The system energy efficiency is significantly increased,while SCMA performs better than CDMA and OFDMA both in SE and EE while satisfying the QoS requirements,since the proposed methods have shown a better network mapping matrix based on power allocation and codebook assignment.The research results enriched existing SCMA theories related to energy efficiency.