Abstract
In this thesis, we propose a Non-orthogonal Multiple Access (NOMA) based Device-to-device (D2D) communication system underlying cellular networks to achieve higher spectral efficiency and system sum rate. We consider a many-to-many scenario for D2D communication. There are multiple D2D pairs allowed to reuse the same RB and each D2D pair is allowed to reuse more than one RB. However, there are mutual interference between D2D pairs and CUE but also inter D2D pairs. We should determine the permitted D2D pairs and control the transmission power of D2D pairs in order to guarantee the minimum rate requirement of CUEs and maximize the system sum rate in every RB simultaneously. We propose a method to sort the reusable RBs of each D2D pairs in order to let the allocation more efficiency. And we also propose a heuristic method to determine the permitted D2D pairs and consider both total throughput and the number of satisfied D2D pairs. In the step of the power control for D2D pairs, we formulate some constraints in order to guarantee the minimum rate requirement of CUEs. Simulation results show that the proposed NOMA-based D2D communication system can improve both of the spectrum efficiency and the system sum rate.