D2D/蜂窝通信模式切换与联合功率控制方案

设备直连（Device-to-Device, D2D）通信技术通过复用蜂窝系统的频谱资源提高频谱利用率，但D2D的引入会给蜂窝系统带来干扰。如何合理地选择D2D/蜂窝通信模式并进行功率优化控制，成为减小D2D和蜂窝系统间干扰、提升网络性能的关键。本文考虑D2D用户复用蜂窝上行链路场景，提出了一种基于距离和联合功率控制的通信模式选择方案。在该方案中，D2D用户和蜂窝用户与基站距离的比值决定了D2D用户是否采用Underlay模式进行通信，进而在约束蜂窝用户和D2D用户发射功率的条件下实现D2D链路和蜂窝链路的联合功率控制，最终推导出能够最大化系统总吞吐量的最优用户功率分配方案。根据仿真结果，本文提出的联合功率控制方案能够在降低系统间干扰的同时有效提高D2D和蜂窝系统的总吞吐量，进而提高了系统的性能。 

D2D/Cellular Communication Mode Switching and Joint Power Control Scheme

Device-to-device(D2D) communication technology improves spectrum utilization by multiplexing spectrum resources of cellular systems,but the introduction of D2D will cause interference to cellular systems.How to properly select the D2D/cellular communication mode and perform power optimization control has become the key to reducing interference between D2D and cellular systems and improving network performance.This article considers the scenario of D2D user multiplexing cellular uplink,and proposes a communication mode selection scheme based on distance and joint power control.In this solution,the ratio of the distance between the D2D user and the cellular user to the base station determines whether the D2D user uses the Underlay mode to communicate,and then the combined power of the D2D link and the cellular link is achieved under the constraint of the transmit power of the cellular user and the D2D user Control,and finally derive the optimal user power allocation scheme that can maximize the total system throughput.According to the simulation results,the joint power control scheme proposed in this paper can effectively improve the overall throughput of D2D and cellular systems while reducing the interference between systems,thereby improving the performance of the system.