Research of heterogeneous networks convergence with NOMA

Heterogeneous network (HetNet) is a promising deployment in fifth generation (5G). HetNet consists of Macro BS and underlaid BSs with lower transmission power and smaller coverage. Cell range expansion (CRE) has been widely applied to offload users to pico, which can obtain larger cell splitting gain, achieve more system throughput. However, CRE will introduce severe inter-cell interference. A cross-tier cooperative transmission strategy based on orthogonal frequency division multiple access(OFDMA) is applied to transform inter-cell interference into desired signal. In order to further improve the spectrum efficiency and user experience, the limitation of orthogonal multiple access (OMA) need to be broken. So in this paper, we propose a heterogeneous collaborative communication strategy with non-orthogonal multiple access (NOMA) to improve system throughput and mitigate the inter-cell interference. Simulation results indicate that the cooperative scheme with NOMA can achieve higher network throughput.