Energy efficiency optimization for MM-NOMA heterogeneous network with wireless backhauling and energy harvesting

A novel architecture of massive MIMO-NOMA (MM-NOMA) based two-tier heterogeneous network is proposed to accommodate huge traffic while considering wireless backhaul transmission is presented in this paper. In addition, full-duplex transmission and energy harvesting are also explored to enhance system performance. Simultaneous wireless information and power transfer (SWIPT) technique has been applied at small cell base station for harvesting energy. First, signal to interference plus noise ratio (SINR) and rate equations are modeled for the proposed network where harvested energy and energy efficiency (EE) are also defined. EE is then optimized by determining the time splitting factor assignment, bandwidth allocation, and power allocation subject to constraints of backhauling, minimum harvested power and quality of service. The formulated optimization problem is non-linear and non-convex. It is difficult to obtain the optimal solution, hence a sub-optimal algorithm is proposed. Furthermore, the complexity of the proposed algorithm is examined and simulation results demonstrate the effectiveness of the proposed algorithm by comparing with existing benchmark schemes.