Research On Resource Allocation Algorithm Of D2D Communication Technology Underlaying Mobile Cellular Networks

With the advent of the era of 5G and the Internet of Things(IoT),large-scale intelligent terminals are constantly emerging,and communication traffic is exploding.In order to improve the communication quality of users and solve the problem of insufficient spectrum resources,researchers have proposed D2D(Device-to-Device)communication technology.D2D provides a theoretical basis for solving these problems.It can cope with the challenges of large-scale intensive access well,which are brought by the IoT and 5G.Therefore,D2D communication technology has become a research hotspot in academic circles in recent years.D2D communication technology,also known as a terminal direct connection technology,is different from traditional cellular communication technology.It is also quite different from short-range wireless communication technologies,such as WiFi,Bluetooth,NFC,and Zigbee.The core of D2D communication technology is that it does not use the base station as the communication relay and works in the licensed frequency band.These aspects determine that it has the advantages of traditional cellular communication technology and short-range wireless communication technology,as well as the advantages of high spectrum utilization,low base station load,high transmission rate,and so on.D2D communication technology has broad application prospects in the fields of car networking,traffic offloading,commercial activities,information sharing and emergency communications.This thesis studies the resource allocation algorithm of D2D communication technology in mobile cellular networks to realize simultaneous communication between D2D users and cellular users.The link multiplexing mode of resource allocation is divided into uplink multiplexing mode and downlink multiplexing mode.Since the uplink multiplexing mode can effectively control system interference and can maximize the advantages of D2D communication technology,this thesis focuses on the resource allocation problem of one-to-one and many-to-one pairing between D2D users and cellular users in this multiplexing mode and proposes two new resource allocation algorithms.(1)In the single-cell scenario where the number of D2D users does not exceed the number of cellular users,this thesis proposes a resource allocation algorithm based on throughput maximization for one-to-one allocation scenarios.First,according to the interference existing in the system(i.e.,the interference between D2D communication link and cellular communication link in the same channel),the reusable cellular multiplexing sets can be founded for each D2D user.Then,the reusable spectrum resource is initially selected for each D2D user according to the selected cellular multiplexing sets.Finally,the final multiplexed cellular resource used by each D2D user is determined through performing a channel switching policy and a power control algorithm.This can maximize the throughput of the cellular network.(2)When the number of cellular users is less than the number of D2D users in a single-cell scenario,a large number of D2D users cannot access the system if one-to-one allocation is adopted.In order to meet the needs of more D2D users,an interference control and resource allocation algorithm which is aimed to many-to-one allocation scenarios is proposed.Compared with the one-to-one algorithm,this algorithm increases the interference between D2D links in the same channel,which makes the interference situation more complicated.In this regard,this thesis constructs an interference graph firstly by using the interference between communication users in a cellular network and obtains a channel reuse sets for each D2D user according to the constructed interference graph.Then,the priority is set for each D2D user,and the channel resources that can achieve the optimal system performance are determined for the D2D users according to the channel reuse sets and the priority.The simulation results show that the two proposed algorithms which are aimed to the one-to-one and many-to-one allocation scenarios can significantly improve the throughput of mobile cellular networks and the access rate of D2D users,and they also can ensure the communication quality of cellular users and D2D users.