Research On Energy-efficient Resource Sharing Schemes For Noma Cellular Networks

Non-orthogonal multiple access(NOMA)technology can support the information transmission of multiple users with the same frequency at the same time.Therefore,it has become one of the significant candidate technologies in fifth generation(5G)mobile communication networks.The interference caused by spectrum resource sharing in NOMA cellular networks is an important factor affecting the improvement of system performance.A reasonable resource sharing scheme can not only suppress the interference,but also improve the spectral efficiency and energy efficiency of the system.Hence,this thesis focuses on the resource sharing schemes in NOMA cellular networks in the following two aspects:Firstly,an energy-efficient power allocation algorithm for NOMA cellular and full-duplex Device-to-Device(D2D)sharing system is proposed.In the sharing system,our goal is to maximize the system energy efficiency by optimizing the power allocation on the premise of user’s minimum transmission rate,maximum transmission power and successful successive interference cancellation(SIC)decoding.In order to solve the non-convex and nonlinear fractional programming,a double-layer iterative algorithm is proposed.Among them,the outer iterative algorithm solves the nonlinear fractional structure of the objective function using Dinkelbach method,and the inner iterative algorithm solves the non-convex structure of the objective function using D.C.(Difference of Convex or Concave,D.C.)algorithm.Simulation analysis show that the communication scheme proposed in this thesis can achieve higher performance in terms of system energy efficiency under the condition of the requirements of minimum transmission rate.Secondly,an algorithm to maximize the secure energy efficiency of NOMA secure transmission system based on simultaneous wireless information and power transfer(SWIPT)is proposed.In the system,the secure energy efficiency of the system is maximized through joint power allocation and splitting factor optimization while ensuring user’s minimum secure rate,maximum transmission power,energy harvest and successful SIC decoding.The non-convex and nonlinear fractional characteristics and the coupling of power allocation and splitting factor make the optimization problem more difficult to solve.Therefore,an alternating optimization algorithm based on sub-problem decomposition which means power allocation problem and splitting factor problem is proposed.The simulation analysis show that the proposed communication scheme has better performance in system secure energy efficiency.In conclusion,the energy efficient resource sharing schemes of NOMA cellular networks proposed in this thesis are able to greatly improve the system energy efficiency and provide certain technical support for the practical application of NOMA communication technology.