With the evolution of the 5G, 6G and beyond, device-to-device (D2D) communication has been developed as an energy-, and spectrum-efficient solution. In cellular network, D2D links need to share the same spectrum resources with the cellular link. A reconfigurable intelligent surface (RIS) can reconfigure the phase shifts of elements and create favorable beam steering, which can mitigate aggravated interference caused by D2D links. In this paper, we study a RIS-assisted single cell uplink communication network scenario, where the cellular link and multiple D2D links utilize direct propagation and reflecting one-hop propagation. The problem of maximizing the total system rate is formulated by jointly optimizing transmission powers of all links and discrete phase shifts of all elements. The formulated problem is an NP-hard mixed integer non-convex non-linear problem. To obtain practical solutions, we capitalize on alternating maximization and the problem is decomposed into two sub-problems. For the power allocation, the problem is a difference of concave functions (DC) problem, which is solved with the gradient descent method. For the phase shift, a local search algorithm with lower complexity is utilized. Simulation results show that deploying RIS and optimizing the phase shifts have a significant effect on mitigating D2D network interference.

中文翻译：

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可重新配置的智能表面辅助设备到设备通信

随着 5G、6G 及更高版本的演进，设备到设备 (D2D) 通信已被开发为一种节能和频谱高效的解决方案。在蜂窝网络中，D2D链路需要与蜂窝链路共享相同的频谱资源。可重构智能表面 (RIS) 可以重新配置元素的相移并创建有利的波束转向，从而减轻 D2D 链接引起的加剧干扰。在本文中，我们研究了 RIS 辅助的单小区上行链路通信网络场景，其中蜂窝链路和多个 D2D 链路利用直接传播和反射一跳传播。通过联合优化所有链路的传输功率和所有元件的离散相移来制定最大化系统总速率的问题。公式化的问题是一个 NP-hard 混合整数非凸非线性问题。为了获得实用的解决方案，我们利用交替最大化并将问题分解为两个子问题。对于幂分配，问题是凹函数差分（DC）问题，用梯度下降法解决。对于相移，使用复杂度较低的局部搜索算法。仿真结果表明，部署 RIS 和优化相移对减轻 D2D 网络干扰具有显着效果。对于相移，使用复杂度较低的局部搜索算法。仿真结果表明，部署 RIS 和优化相移对减轻 D2D 网络干扰具有显着效果。对于相移，使用复杂度较低的局部搜索算法。仿真结果表明，部署 RIS 和优化相移对减轻 D2D 网络干扰具有显着效果。