基于加权二部图及贪婪策略的蜂窝网络D2D通信资源分配

D2D(Device-to-Device)通信是解决频谱资源稀缺问题的关键技术之一。该文研究蜂窝网络中“many-to-many”的复杂场景，即单个RB(Resource Block)可以分配给多对D2D用户重用，并且允许单个D2D用户对使用多个RB，其中D2D用户对数量远多于蜂窝用户设备(Cellular User Equipment, CUE)数量和RB数量。考虑CUE对资源使用具有更高优先级，将此优化问题分解为蜂窝用户资源分配和D2D用户资源重用两个阶段。在第1阶段，提出基于公平性的循环二部图匹配(Fairness-based Circular Bipartite Graph Matching, FCBGM)算法，将现有的RB分配给所有CUE，以最大化蜂窝用户和速率。在第2阶段，分别提出基于二部图的资源重用(Bipartite Graph-based Resource Reuse, BGRR)算法和基于贪婪策略的资源重用(Greedy-based Resource Reuse, GRR)算法，目标是将已经分配给CUE的RB再次分配给D2D用户重用，以最大化系统和速率，同时确保CUE的基本速率需求。仿真结果表明，在D2D用户对数量远大于CUE数量和RB数量的情况下，与现有典型算法相比，所提算法能够有效提高系统和速率，增加D2D接入率，同时兼顾用户公平性和服务质量需求。

Resource Allocation Based on Weighted Bipartite Graph and Greedy Strategy for D2D Communication in Cellular Networks

Device-to-Device (D2D) communication is one of the key technologies to solve the issue of spectrum resource scarcity. In this paper, a complex “many-to-many” scenario in cellular networks is investigated, where a Resource Block (RB) could be reused by more than one D2D pair, and a D2D pair is also allowed to use multiple RBs. Moreover, the number of D2D users is larger than that of Cellular User Equipments (CUEs) and RBs. Considering that CUEs have higher priority on resource, this optimization problem is decomposed into two stages: cellular users resource allocation and D2D user resource reuse. In the first stage, a Fairness-based Circular Bipartite Graph Matching (FCBGM) algorithm is proposed, which allocates the existing RBs to all CUEs to maximize the sum data rate of cellular users. In the second stage, a Bipartite Graph-based Resource Reuse (BGRR) algorithm and a Greedy-based Resource Reuse (GRR) algorithm is proposed, and the goal is to re-assign the RBs, which are already allocated to CUEs, to the D2D pairs in a way to maximize the system sum data rate while ensuring the basic data rate requirements of CUEs. Simulation results show that when the number of D2D pairs is much larger than that of CUEs and RBs, compared with the existing typical algorithms, the proposed algorithm can effectively improve system sum data rate and D2D access rate while guaranteeing user fairness and quality of service.