Fairness Based Power Allocation optimization of Cooperative NOMA with SWIPT Network

In this paper, a power allocation problem for cooperative communication network with non-orthogonal multiple access and simultaneous wireless power transmission (C-NOMA-SWIPT) is considered. We both consider the half duplex cooperative NOMA with SWIPT and the full duplex cooperative NOMA with SWIPT network. There are two users in each cooperative cluster. The strong user receives the information and energy from BS simultaneous using power splitting, and then decode and forward relay data for the weak user. On the purpose of the fairness of the data rate, we formulated the optimization problem to maximize the minimum achievable user data rate in each NOMA with SWIPT user cluster, which is a non-convex quadratic programing problem (NP-hard). We design a two step subproblem (The power allocation and the energy harvest) strategy to optimize the system model with Lagrange Dual Method and the Interior Point Method. In addition, a hybrid half/full-duplex cooperative NOMA scheme was proposed to dynamically switches between the HD-CNOMA-SWIPT and FD-CNOMA-SWIPT. Numerical results demonstrate that our proposed scheme can achieve a better performance compared with conventional schemes.