基于LTE-A网络的D2D发现机制设计与优化

发布时间：2018-03-24 07:02

本文选题：D2D　切入点：设备发现　出处：《北京交通大学》2017年硕士论文

【摘要】：近年来,设备终端直接通信技术(D2D,Device-to-Device)作为未来5G场景下的热点研究内容之一,已经受到了越来越广泛地研究和讨论。D2D设备发现和D2D数据通信是实现近邻用户服务的两项关键技术,其中,D2D设备发现是指D2D设备感知和识别周围潜在通信用户的过程,而D2D数据通信是指用户间通过建立物理链路进行数据传输的过程。在上述关键技术中,D2D设备发现是D2D数据通信的首要条件,对D2D通信具有重要的影响。然而,现有的D2D设备发现机制普遍存在发现概率低、发现时延大等问题,为了解决这些问题,本文主要从以下三个方面进行了研究:首先,基于LTE-A网络中的随机接入技术设计了单小区场景下的一种基于竞争的D2D设备自主发现机制。该机制引入随机退避策略以减少碰撞,提高设备发现概率。为了进一步减少D2D用户在设备发现过程中的碰撞,本文提出了基于接入等级限制的动态拥塞控制机制。仿真结果表明,本文提出的D2D设备发现机制能够提高D2D设备的发现数量和资源利用效率,降低平均发现时延。其次,结合3GPP最新标准化进展,引入公共安全和普通商用服务共存的网络场景,提出了基于优先级的混合D2D设备发现机制。针对公共安全服务用户,提出了基站辅助下的动态资源调度机制,而针对普通商业服务用户,本文采用竞争和动态分配相结合的混合资源调度机制。仿真结果表明,所提出的混合设备发现机制能够提高系统发现用户数量,降低平均能量损耗。最后,本文对多小区场景下带内泄漏干扰和同频干扰对D2D设备发现性能的影响进行研究,并在此基础上建立了基于随机几何的D2D接收端信干比模型和设备发现概率模型。仿真结果表明,带内泄漏干扰随发现资源和上行蜂窝资源之间距离的减小而增大,进而导致设备发现概率降低。为了降低D2D设备发现过程面临的干扰,提高设备发现概率,本文还提出了一种基于用户距离的功率控制机制,仿真结果证明了该机制的有效性。
[Abstract]:In recent years, as one of the hot research contents in the future 5G scenario, the direct communication technology of device terminal (D2DN) Device-to-Devicehas been studied and discussed more and more widely. D2D device discovery and D2D data communication are two key technologies to realize the service of the nearest neighbor user. D2D device discovery refers to the process of perceiving and identifying potential communication users around D2D devices. D2D data communication refers to the process of data transmission between users by establishing physical links. Among the above key technologies, the discovery of D2D devices is the primary condition of D2D data communication and has an important impact on D2D communication. In order to solve the problems of low discovery probability and large discovery delay in the existing D2D device discovery mechanism, this paper mainly studies the following three aspects: first of all, Based on the random access technology in LTE-A network, a competitive D2D device autonomous discovery mechanism is designed in single cell scenario, which introduces a random Backoff strategy to reduce collisions. In order to further reduce the collision of D2D users in the process of device discovery, a dynamic congestion control mechanism based on access level restriction is proposed. The simulation results show that, The D2D device discovery mechanism proposed in this paper can improve the number of D2D devices and the efficiency of resource utilization, and reduce the average discovery delay. Secondly, combined with the latest standardization progress of 3GPP, the network scenario of public security and common commercial services co-exist is introduced. A hybrid D2D device discovery mechanism based on priority is proposed, and a dynamic resource scheduling mechanism assisted by base station is proposed for users of public security services. The simulation results show that the proposed hybrid device discovery mechanism can increase the number of users found in the system and reduce the average energy loss. In this paper, the effects of in-band leakage interference and co-frequency interference on the discovery performance of D2D devices in multi-cell scenarios are studied. On this basis, a D2D receiver signal-to-interference ratio model and a device discovery probability model based on random geometry are established. The simulation results show that the in-band leakage interference increases with the decrease of the distance between the discovery resource and the uplink cellular resource. In order to reduce the interference in the process of D2D device discovery and improve the probability of device discovery, a power control mechanism based on user distance is proposed in this paper. The simulation results show that the mechanism is effective.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5

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