Transmission scheduling and congestion control for multi-hop D2D underlaying cellular networks

In this paper, we study optimal transmission scheduling and congestion control in multi-hop device-to-device (D2D) communications underlaying cellular networks. The optimization is not only based on the cellular and D2D link qualities but it also takes the interference situation for each possible mode and the quality of service (QoS) requirements of each user into account. The problem is formulated as an overall time-averaged system throughput maximization with system stability provision. By manipulating the formulation and using the Lyapunov optimization theory, the original problem can be decomposed into an end-to-end rate control problem and a joint routing, channel assignment, and power allocation problem. We provide a lower bound of the system throughput and thus the proposed algorithm can achieve an approximate maximization. Simulation results show that the algorithm simultaneously improves the system throughput and stability compared to the scenario where communication modes are fixed for all sources.