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。     

蜂窝网络中D2D通信模式选择和信道分配算法

设备到设备(D2D)通信中,不合理的模式选择和信道分配方案会引入干扰,严重时不仅不能体现D2D通信优势,而且还将导致蜂窝用户传输速率下降。针对这一问题,文章提出了一种蜂窝网络中D2D模式选择和信道分配算法。仿真结果表明,新算法能够在有效的平衡蜂窝网络中D2D用户接入率和系统总吞吐量的同时,最小化用户之间的干扰。     

D2D通信的联合资源分配和功率控制方法

设备到设备(D2D)通信对未来蜂窝网络是一种很有前途的技术,它可以有效地提高系统的吞吐量和延长用户设备的电池寿命。然而,在蜂窝网络中,D2D通信共享频谱会造成干扰。为消除干扰,充分利用D2D通信的优势,提出了一个联合的频谱资源分配和功率控制(RAPC)方法,该方法能够实现总吞吐量最大化,同时保证D2D用户和蜂窝用户所需的最小速率。提出的资源分配和功率控制的优化问题,通过量子粒子群(QPSO)得到近似优化方案的最优解,其中的量子粒子代表资源分配和功率控制的方法,同时制定惩罚函数删除不可行的方法。仿真结果表明,该方法具有更好的性能、系统吞吐量、功率效率和最小速率比其他方法令人满意。     

异构蜂窝网络中基于Stackelberg博弈的能效优化算法

设备到设备(Device To Device,D2D)通信允许移动终端无需通过基站而进行直接通信。为提高蜂窝系统能效,引入D2D通信共享频谱资源形成异构蜂窝网络。本文将D2D通信的能效优化问题转化为博弈收益最大化问题,并提出了一种基于Stackelberg博弈的分布式功率控制算法。针对系统模型中存在的跨层干扰以及层内干扰,该算法建立了干扰价格系数与D2D对发送功率之间的函数关系,并求解出给定干扰价格系数下D2D对最佳发送功率的闭合表达式。仿真结果表明所提算法能够在最大化基站端蜂窝用户收益的基础上有效提高D2D对的总能效。      

基于用户中断概率的D2D通信干扰协调与资源分配

在LTE系统中引入设备直传(D2D)通信技术,会因为D2D用户复用蜂窝用户资源进行通信而产生同频干扰.在现有的干扰协调与资源分配研究中,都需要基站获取各个通信链路的信道状态信息(CSI),但这样无疑会增加基站的信令负担.为减小干扰与基站的信令负担,提出了一种基于用户中断概率的干扰协调与资源分配算法,首先在保证蜂窝用户正常通信的情况下,通过限制D2D用户到基站间的距离来降低干扰;其次通过遍历所有蜂窝用户的频谱资源,选择能使D2D用户的总中断概率最低的频谱资源进行复用.仿真结果表明,所提算法能够在保证蜂窝用户正常通信的情况下,明显降低D2D用户的平均中断概率,同时还能够降低基站信令负担.     

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。      

全负载蜂窝网络下多复用D2D通信功率分配算法研究

针对全负载蜂窝网络中D2D通信的功率分配问题,该文提出了一种基于非合作完全信息博弈纳什均衡解的多复用D2D通信功率分配算法。以优先保证蜂窝用户通信质量与D2D用户接入率为前提,设置D2D通信系统上行链路帧结构,之后建立非合作完全信息博弈系统模型,引入定价机制到功率分配博弈模型中并分析纳什均衡解的存在性与唯一性,最后给出该模型的分布式迭代求解算法。仿真结果表明,随着D2D用户复用数量的增加,该算法在提升系统吞吐量的同时,能有效地控制系统内部干扰,大幅度降低系统总能耗。     

基于博弈论的D2D通信功率控制算法

针对多D2D通信用户共享蜂窝网络频谱资源中的干扰进行研究,为了减少D2D用户间干扰带来的影响,提出了一种改进的基于博弈论的D2D通信功率控制算法。算法中的博弈者是复用相同频谱资源的多D2D通信用户。建立了博弈模型,并在代价函数中引入代价因子,确定了效用函数,得到参与博弈的D2D用户的最优响应函数。文中对博弈均衡特性进行分析,证明了模型中的策略能够达到稳定状态。通过仿真实验验证了算法的有效性,并且与其他算法对比,证明使用此改进算法的D2D用户吞吐量更大,公平性更高。     

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。     

基于非均衡求解的D2D多复用通信资源块分配算法研究

针对小区内D2D多复用的通信资源块分配问题,该文以一个D2D用户分别复用2个和3个蜂窝为基础,提出基于非均衡求解的D2D多复用模式下的资源块分配方案。利用博弈论将资源块划分问题转化为求解被复用蜂窝用户收益联合最大问题。当纳什均衡解不存在时,分析目标函数特性,在可行域内求解“最优解”,保证对不均衡解处理的最优性;对于均衡解存在的情况,将其取整后作为资源分配方案依据,保持其最优性。通过理论分析及仿真实验表明该算法可以提升系统吞吐率,提高小区通信性能。     

混合D2D蜂窝网络中基于模拟退火算法的资源调度策略

D2D通信是未来5G网络中一种近距离直通通信方式,在通信过程中,信息直接由发送端传给接收用户,而不需要经过基站的转发.在传统蜂窝网络中引入D2D通信可以极大地提升系统的总吞吐量、增大频谱资源的利用率以及降低发射终端的功耗.主要介绍了一种适用于混合D2D蜂窝网络中的资源分配方法,通过拉格朗日乘子法结合模拟退火算法实现频谱资源的分配,提出一种同时考虑信道容量和能耗的基于模拟退火算法的资源调度策略.本算法在维也纳仿真平台上经仿真验证,相比于传统贪婪优化算法,可以明显增大系统总吞吐量和频谱资源利用率.另外,算法中采用了分布式资源调度方法,D2D用户根据算法步骤自行搜索适合的目标信道并计算其发射功率,可以有效减少基站的信令开销.     

Cooperative caching game based on social trust for D2D communication networks

Content sharing via device‐to‐device (D2D) communications has become a promising method to increase system throughput and reduce traffic load. Due to the characteristic of spectrum sharing in D2D network, confidentiality is becoming a key issue in content transmission. Secure communication in D2D networks is generally guaranteed by a physical‐layer security mechanism. However, this method sacrifices the system transmission rate while ensuring security. Since mobile devices are carried by humans, we can leverage their trust relations to enhance the security of communications. As much, considering the psychology structure and social attributes of mobile users, we build a multidimensional trust evaluation mechanism to evaluate the trust relationship between users, and we pick out the trusted users based on the decision‐theoretic rough sets. By sharing content only between trust users, we can enhance the security of content transmissions without relying on physical‐layer security measures. Meanwhile, content caching is now widely used to improve accessing efficiency and reduce traffic load on cellular networks. However, caching content for other users incurs additional cost, which results in selfish and noncooperative behavior in users. Considering such selfishness, we introduce a cooperative caching game based on multidimensional trust relations to motivate users to cache contents for other devices. In this game, the trust relations and physical distance between two users are considered to formulate the cost function. Furthermore, we introduce an incentive caching algorithm based on social trust to minimize the total cost in the D2D network.     

An access-aware pricing strategy for the evolved packet system

The evolved packet system (EPS) integrates third generation partnership project (3GPP) and non-3GPP wireless access networks to provide mobile users with ubiquitous access to a diverse set of multimedia services. As we know, 3GPP and non-3GPP access networks differ significantly with respect to bandwidth capacity, coverage range, and service cost. It is crucial to enable efficient load balancing between 3GPP and non-3GPP access networks to improve resource utilization, and still maximize revenue generation. From an economic point of view, pricing plays an important role in achieving load balancing in the EPS. This paper proposes an access-aware pricing strategy for the EPS to achieve load balancing between 3GPP and non-3GPP access networks and to maximize revenue generation for network operators. In addition, this paper develops an analytical model for the system using the proposed access-aware pricing strategy. With the analytical model, this paper also proposes an iterative method for determining the optimal pricing that maximizes revenue generation in the EPS. The analytical model is verified by simulation.     

UAV-assisted multi-hop D2D relaying for communication in large disaster area

An unmanned aerial vehicle (UAV)-assisted communication is a promising technique for enabling ground users in a non-functional area (NFA) or disaster area to communicate. All the base stations in the disaster area may be partially or fully damaged due to the natural calamity. Device-to-device (D2D) communication can be a viable solution for immediate connection between users in an NFA. We propose a UAV-assisted multi-hop D2D communication following a hybrid power-time switching (PTS) in this paper. Moreover, a D2D user of a cluster can communicate with another D2D user in a different cluster through UAVs. However, D2D users can harvest energy from their respective ad hoc energy stations and forward the information to the nearby D2D user following a hybrid PTS-based strategy. We propose a time frame for the same and show a node-based energy harvesting strategy. The expressions of outage probability, throughput, end-to-end energy consumption, and energy efficiency are developed for the Rician and Nakagami-m faded channel. The impact of several network parameters such as energy harvesting factor, energy harvesting efficiency, and fading parameter on the network performance is also indicated.     

Swarm intelligence‐based radio resource management for V2V‐based D2D communication

Internet of Things is a promising paradigm that provides the future network of interconnected devices. Device‐to‐Device (D2D) communication, which is considered as an enabler for vehicle‐to‐everything applications, has become an emerging technology to optimize network performance. In this paper, we study the Radio Resource Management (RRM) issue for D2D‐based Vehicle‐to‐Vehicle communication. The RRM key role is to assure the proficient exploitation of available resources while serving users according to their quality of service parameters. An Ant Colony Optimization (ACO)‐based Resource Allocation (ACORA) scheme is proposed in this paper. Swarm intelligence algorithm ACO is adopted to reduce the computational complexity while realizing satisfactory performance. Simulation results show promising performance of our proposed ACORA scheme.     

基于Stackelberg博弈的WCDMA网络收益最大化计费的研究

该文研究了在WCDMA网络中如何选择价格来最大化网络收益.没有采用拥塞相关的计费,而是对每个用户有效传输的单位吞吐量收取固定的费用,但每个用户的传输速率是网络拥塞和单位带宽价格的函数,并在此基础上提出了用户净效用函数.利用Stackelberg博弈,建模网络与用户之间的交互,即一方面网络管理者设定价格,以便实现收益最大化,而用户通过自优化效用函数来寻找新的均衡点对此做出响应.本文提供了网络收益与接纳用户数目的定量关系,并研究了网络降低用户传输速率以增大网络容量和拥塞控制的经济动机.     

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。     

An intra–inter-cell device-to-device communication scheme to enhance 5G network throughput with delay modeling

As the number of mobile users is growing, so is the demand for more bandwidth. It becomes important that the required bandwidth and spectral resources do not scale with traffic in the next generation of wireless networks [i.e. fifth generation (5G)]. Device-to-device (D2D) communication underlaying cellular networks has been recognized as an essential technique in 5G networks. By applying definite principles and strategies, D2D communication not only increases the spectral and energy efficiency, but also enhances network throughput, network coverage and reduces delay. In this paper, we present an intra–inter-cell D2D communication scheme to enhance throughput of 5G networks. We study call setup delay of two developed communication scenarios and throughput gain comparing three systems. Firstly, we show the enhancements required in current cellular architectures to support inter-cell D2D communication. We develop protocols for two scenarios and demonstrate how architecture entities cooperate for the call setup between D2D users. We measure the overall call setup time for the developed protocols and derive a closed-form delay formula to estimate call setup time probability. Secondly, we perform simulations using a topology similar to that found in realistic urban environments to study throughput gains of the proposed intra–inter-cell D2D communication scheme. We compare three systems in terms of throughput: (1) pure cellular system (with cellular users only), (2) pure cellular system with intra-cell D2D users sharing the same cellular resource, and (3) pure cellular system with intra–inter-cell D2D users sharing the same cellular resource. Simulation results show that the proposed scheme substantially increases the network throughput and spectrum efficiency.     

D2D通信中一种资源分配与功率控制结合的方案

以underlay方式工作的D2D(Device-to-Device)通信通过资源共享复用蜂窝网络中的资源,在提高系统资源利用率的同时,对已有蜂窝链路带来了同频干扰。为了减小因无线资源复用带来的干扰,提出了一种资源分配与功率控制相结合的方法。以最小化系统干扰为目的,通过在D2 D链路之间合理地分配资源,保证了蜂窝链路的通信质量;同时动态地调整D2 D链路的发射功率,在保证相应蜂窝链路干扰可控的情况下,合理提高了D2 D链路的通信质量。仿真结果表明,与现有方案相比,所提出的算法能够有效地提高D2 D通信与蜂窝用户共存场景下的系统性能。