D2D辅助的协作中继NOMA系统中TSRS策略及其中断性能分析

该文研究了D2D辅助的协作中继NOMA（DC-NOMA）网络,在中继用户（RU）转发信息的第二时隙,利用RU到蜂窝中心用户（CCU）的D2D通信链路传输新的信号。为了提高传输可靠性,设计了新的信号检测策略,通过完全利用边缘信息消除了用户间的干扰。基于新的信号检测策略,提出了一种两阶段中继选择策略（TSRS）。在满足蜂窝边缘用户（CEU）可靠接收的中继集合中,选择使CCU成功解码概率最大的中继。为了评估所提出的DC-NOMA方案,推导了每个用户的确切中断概率且通过仿真得到验证。仿真结果表明,在高信噪比区域,该文所提出的基于新的信号检测策略的DC-NOMA在TSRS方案下的中断性能优于部分中继选择方案（PRSS）和传统的DC-NOMA。特别地,增大中继数量可有效提高DC-NOMA系统的中断性能。      

面向5G的D2D簇内信息共享机制

D2D (device-to-device)通信是5G网络中的重要技术,有利于提升数据分发业务传输效率;然而,由于D2D通信引入了大量额外信令开销,当前的增强多播方案无法解决高效数据传输与低效信令流程之间的矛盾,降低了整体性能增益.为此,提出了一种基于多维矢量分析的最小化信令开销的D2D簇内信息共享算法,包含集中式与分布式两种实现方式,能通过自适应地选择D2D多播重传发射者和多播重传数据分组,大幅减少簇内重传次数,达到显著降低信令开销和传输时延的目的.     

基于D2D通信系统中的一种跨层中继选择算法

在D2D通信系统与蜂窝网络共存的场景下,引入中继节点可有效提高D2D链路的吞吐量和D2D用户对蜂窝用户的干扰。文中基于译码转发模式,结合跨层协作通信的思想,提出了一种基于物理层和数据链路层的跨层中继选择算法。该算法结合物理层的信道状态信息和数据链路层的队列状态信息,两个参数进行最优中继节点的选择。并最终通过仿真验证表明,基于跨层中继选择算法可提高通信系统的吞吐量,同时降低了通信系统的平均时延和数据包错误率。     

异构网络中基于能效优化的D2D资源分配机制

针对异构网络中D2D通信复用蜂窝用户频谱时存在的频谱分配问题,该文提出一种基于改进离散鸽群优化(PIO)算法的D2D通信资源分配机制。通过设置信干噪比(SINR)门限值来保证用户的通信服务质量(QoS),采用功率控制算法为用户设置发射功率,使用基于运动权值的二进制离散鸽群优化(MWBPIO)算法为D2D用户进行资源分配,并将D2D通信技术与中继技术进行有效结合,为边缘用户建立D2D中继链路,保证边缘用户的通信质量,最大化系统性能目标。仿真结果表明,该方案有效抑制了异构通信系统中引入D2D用户后导致的干扰问题,提高了边缘用户的通信质量和系统的频谱利用率以及系统的能效。     

基于LTE D2D技术的车联网通信架构与数据分发策略研究

基于5G通信技术的车联网面临高速率、低时延、高可靠性和大量流媒体数据分发等需求,提出了一种基于LTE D2D的车联网通信架构,设计基于运动一致性的车辆分簇算法,有效增加持续D2D通信时间,提高通信可靠性;其次,针对簇内车辆的流媒体数据分发,提出一种带时延约束的D2D协作中继转发策略,设计最优中继选择算法,大幅提高数据传输速率,提升网络吞吐量。     

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使能蜂窝网络中存在主动窃听者的物理层安全研究

D2D通信作为5G移动通信的关键技术,以其能有效提升系统能量效率和频谱效率而备受瞩目。在系统中存在被动窃听者的情况下,D2D带来的干扰也被视为友好干扰来提升蜂窝系统的物理层安全性能。但如果存在的是主动窃听者, D2D带来的干扰就会影响蜂窝系统安全稳健的传输性能。因此本文考虑在系统中存在可以智能选择被动窃听或主动干扰的攻击者的情况下,通过选择最佳的D2D用户并采取协同中继或友好干扰的策略来提升在被动窃听情况下蜂窝网络的安全可达速率和在主动干扰下的数据传输速率,来改进蜂窝系统通信的鲁棒性和安全性。本文将合法用户和主动窃听者之间的相互作用建模为非零和的非协作混合博弈,分析了此混合博弈的纳什均衡的存在性,并通过基于fictitious play(虚拟对策)的算法获得了其纳什均衡解。仿真结果表明该算法优于传统的nearest neighbor(最近距离)算法,并且联合考虑两种D2D协作方式的策略优于只将D2D用户视为友好干扰或是协同中继的策略。      

蜂窝网络中D2D通信的分析与建模

设备与设备间（D2D）通信因其具有诸多优点如有效提高频谱效率、减少通信时延、降低设备能耗等而作为下一代蜂窝网络中的关键技术。本文首先分析了蜂窝网络中D2D通信的分类。其次,运用随机几何数学工具,对蜂窝网络中的蜂窝用户和D2D用户进行数学建模并使用基于距离的模式选择策略分析蜂窝网络中D2D通信的最优平均信息速率及最优的蜂窝用户与D2D用户配比。最后通过MATLAB仿真平台验证结论的正确性及可行性。     

提高蜂窝网络中数据分发效率的D2D协作转发算法

Device-to-Device(D2D)通信是一种移动终端在蜂窝通信系统的控制下使用授权频段进行点到点通信的新型技术。通过允许接收终端间的数据转发,D2D通信可以用来提高蜂窝网络中的数据分发效率。现有的终端间转发算法,没有充分考虑D2D链路的差异,很难实现频谱资源的高效利用。为此,该文提出了一种基于多跳中继的D2D协作转发算法,包括多播和单播两个模式。该算法根据D2D链路质量自适应地选择最优的中继、路由及传输跳数,能够充分利用D2D链路的多信道分集增益。仿真结果表明,该文所提出的算法能够显著地提高D2D转发的资源利用率,进而提升数据分发业务的吞吐量。     

基于蜂窝网络的D2DC组播通信资源分配算法

针对蜂窝网络下的设备对设备集群(device-to-device cluster,D2DC)的多播通信干扰问题,本文设计了一种实用高效的资源分配方案.该方案可以在保证蜂窝通信一定服务质量水平的前提下,有效的为D2DC分配信道以及传输功率,并且能够使系统有效吞吐量的总和最大化.本文首先利用部分设备位置信息设计了一种信道分...     

异构云无线接入网场景下D2D通信资源共享与分配

针对异构云无线接入网中的前向链路受限问题,提出了一种基于干扰阈值的设备到设备(Device-to-Device,D2D)多用户分簇方案,并对系统信道和功率资源的分配进行优化。首先根据D2D用户之间的干扰级别,利用着色图理论对多用户进行分簇;然后,在满足D2D用户和蜂窝用户服务质量约束下,建立了基于D2D用户和速率最大化的资源分配模型,并进一步采用二分法对已分簇的D2D用户进行功率优化分配。仿真实验结果验证了所提方案相比传统方案,系统频谱利用率提高了55%以上。     

D2D通信系统中基于QoS的分簇信道分配算法

D2D(Device-to-Device)通信作为第五代移动通信(5G, 5-generation)的关键技术之一,因其高频谱效率、低能耗等优点受到广泛关注。为了更好地满足D2D用户的服务质量(quality of service, QoS)需求,本文引入用户满意度的概念,提出了一种基于QoS的分簇信道分配算法。该算法运用图论着色方法为D2D用户分配信道,可分为三个步骤:首先构建D2D用户间的干扰图,然后在保证蜂窝用户QoS需求的情况下建立D2D用户的可用颜色列表,最后为D2D用户分簇,位于同一簇内的用户可以共享信道。仿真结果表明,本文算法可以有效提高D2D用户的满意度和系统公平性。      

System utility based resource allocation for D2D multicast communication in software-defined cellular networks

Device-to-device (D2D) multicast communication is a useful way to improve the communication efficiency of local services. This study considers a scenario of D2D multicast communication in software defined cellular network and investigates the frequency resource allocation problem. Firstly, we build the system model and formulate the optimization problem. Secondly, a hierarchical scheme to achieve a suboptimal solution is proposed. To select appropriate user equipments (UEs) as potential D2D transmitters (PDTs), a social aware PDT selection method is proposed. Then, a resource allocation algorithm considering users’ priorities is proposed. Furthermore, to study the resource allocation for general system that UEs without priorities, a non-priority considered allocation algorithm is proposed also. Numerical simulation results show that the proposed schemes are effective in improving the system utility and reducing the resource consuming for D2D communications.     

D2D通信中一种基于FFR的动态功率控制方案

工作在underlay方式下的D2D(device-to-device)通信利用资源复用共享蜂窝网络中的资源,在提高频谱资源利用率、降低移动终端功耗的同时,会给已有蜂窝网络带来干扰。在保证D2D用户和蜂窝用户的服务质量的前提下,研究了蜂窝用户和D2D用户的功率控制和资源分配问题。首先引入部分频率复用(FFR)实现蜂窝用户和D2D用户之间的资源划分和复用;然后以系统吞吐量最大化为原则,建立优化目标。结合部分功率控制(FPC)的基本思想,进而提出了一种动态功率控制(DPC)策略。仿真结果表明,所提出的方案能够有效地提高多小区系统的性能。     

时延约束下采用SVC编码的D2D协作视频多播传输方案

为缓解基站的视频流量过载，本文针对时延敏感的实时视频业务，设计一种D2D协作视频多播传输方案。该方案采用可伸缩视频编码（Scalable Video Coding, SVC）对视频流进行编码处理，利用SVC流的分层结构特征来应对多播信道间的差异性。在SVC编码的基础上，为了改善用户观看体验及提升用户所接收的视频质量，所提出的协作式视频传输方案引入有效吞吐量这一概念，在一定时延约束下，根据信道反馈信息灵活地对不同信道上的不同SVC视频层进行码率调整。仿真结果表明，所提出的方案能够有效地减小端到端时延，有效丢失率，提高有效吞吐量。      

Network coded multicast for multi-hop D2D communication systems

ABSTRACT

In this paper, we consider the wireless communication systems where multi-hop Device-to-Device (D2D) networks can coexist with the conventional cellular networks by sharing the downlink resource of cellular users (CUs). A multicast data flow is distributed over the multi-hop D2D networks where network coding (NC) can be employed at the intermediate nodes. To maximize the utility of the multicast flow, we formulate a joint optimization problem for the systems while guaranteeing the quality-of-service (QoS) for regular CUs. We propose a subgradient algorithm to solve the optimization problem by decomposing it into three sub-problems: multicast rate control, NC subgraph selection, and downlink resource reusing. In particular, we develop a greedy algorithm to deal with the downlink resource reusing sub-problem for it is NP hard. Numerical and simulation results prove the superior performance of the proposed techniques compared with the conventional routing scheme.     

基于信干噪比的D2D通信功率控制与资源分配

为了优化长期演进(LTE)系统引入设备直传(D2D)通信后带来的同频干扰、系统边缘用户性能恶化问题,提出一种基于信干噪比(SINR)的多小区D2D通信资源分配方案,通过调整信干噪比阈值将部分蜂窝用户(CU)转化为D2D用户并释放频谱资源进而获得较佳的资源分配策略,同时提出一种基于小区间D2D竞争机制的配置算法有效降低小区间干扰.仿真表明,算法能够有效提升系统容量,并提升小区边缘D2D用户公平性.     

A coalitional game‐based relay load balancing and power allocation scheme in decode‐and‐forward cellular relay networks

In this paper, a game theoretic relay load balancing and power allocation scheme is proposed for downlink transmission in a decode‐and‐forward orthogonal frequency division multiple access‐based cellular relay network. A system with a base station communicating with multiple users via multiple relays is considered. The relays have limited power, which must be divided among the users they support. In traditional scheme, each relay simply divides its transmit power equally among all its users. Moreover, each user selects the relay with the highest channel gain. In this work, we do not apply the traditional relay scheme. It is because the users are distributed randomly, and by applying the traditional relay selection scheme, it may happen that some relays have more users connected to them than other relays, which results in having unbalanced load among the relays. In order to avoid performance degradation, achieve relay load balancing, and maximize the total data rate of the network, a game theoretic approach is proposed, which efficiently assigns the users to relays. The power of each relay is wisely distributed among users by the efficient power allocation scheme. Simulation results indicate that the proposed game‐based scheme can considerably improve the average sum‐spectral efficiency. Moreover, it shows that by applying the game, users who can connect to uncongested relays join them as opposed to connecting to congested relays. Copyright © 2015 John Wiley & Sons, Ltd.     

Enhanced Resource Blocks Management in D2D based Communication for 5G Networks

D2D based communication holds a promising future for 5G networks as they are efficient and can yield high data rates, good signal to noise interference ratio, improved resource-block uploading time, minimized delay from one end to the other and conserved power for transmission. The traditional system of cellular type contains cell edge clients who need a larger resource blocks count as well as time to upload data. Hence the quality of service will be reduced. The relay scheme in the proposal for cooperative type D2D networks is pivoted on the value of channel gain as well as transmission link distance. For bringing down the resource blocks’ count as well as uploading time, the paper is proposing a capable scheme of selection of relays that employs communication of D2D in the situations of uplinking. To begin with, in a cell modeling is done. It contains D2D pairs of multiple types as well as cellular clients. Next, the analysis related to issues of allocating resources as well as control of power is done. In order to lessen the resource blocks as well as their uploading time, the paper in proposal suggests a better blocks management mechanism that uses D2D based communication. Simulated output infers that the method in the proposal is superior to the present methods as far as time to upload contents; resource blocks, SINR, throughput as well as rates of data and Energy Consumption are concerned. Added to that, the stated method conserves 43% of the Energy Consumption of the network clients and while doing that the time to upload the contents is not affected.