【作者】 杨光；

【导师】 曹叶文；

【作者基本信息】 山东大学 ， 通信与信息系统， 2018， 博士

【摘要】 移动数据流量和智能终端接入数目的快速增长给当前的通信系统带来了前所未有的挑战,仅通过升级现有通信网络并不能满足未来移动通信系统的发展需求。自2014年起,下一代通信技术,即第5代移动通信技术(5G)已成为国内外移动通信领域的研究热点。而Small Cell网络及其超密集部署的网络以其高容量、广覆盖、低能耗、灵活部署、低成本安装等诸多优势已成为业界共识的面向5G发展的关键技术之一。Small Cell网络是指由一些低功率的无线接入点组成的蜂窝网络系统,而超密集网络(Ultra-dense Networks,UDN)是通过部署大量Small Cell基站来提升无线系统容量的,这将成为实现增大1000倍的数据流量及达到0.1～1Gbps的用户体验速率等未来5G网络目标的最为有效的解决方案。然而,Small Cell的部署在给当前通信网络注入强大生命力的同时引起的资源分配及干扰问题也无疑会造成网络系统容量降低及用户体验感变差,而以往的适用于宏蜂窝的无线资源分配算法和干扰缓解技术已不再完全适用于Small Cell网络。因此,如何进行Small Cell网络中的资源分配及管理相关干扰是当今无线通信网络亟待解决的问题之一。本论文基于联盟博弈理论、概率论、聚类算法等数学工具与相关优化算法,围绕Small Cell网络的资源分配及干扰管理方案展开广泛调查研究,深入分析了Small Cell网络的行为特点及其所面临的困难和挑战,从Small Cell基站进行合作形成联盟的角度入手,以提升整个网络系统容量为出发点,提出了三种适用于Small Cell网络子信道和功率分配以及同层干扰缓解的方法,为Small Cell网络性能的改善提供了理论依据。本论文的主要工作包括如下四个方面:1)阐述了 Small Cell网络中基于联盟形成的资源分配及干扰技术。分析讨论了合作博弈和非合作博弈的不同之处,深入挖掘了 Small Cell网络中的用户利用无线资源时的竞争与合作行为,剖析了现有文献中所涉及的Small Cell网络中的资源分配及干扰管理方案,从而确立了采用联盟博弈理论研究Small Cell网络中的资源分配及干扰管理的必然性和可行性,为下文奠定了理论基础。2)提出了基于联盟形成的Small Cell网络资源分配方案。针对Small Cell网络的下行通信系统的特点,把Small Cell基站合作的过程规划为一个具有可转移效用的基于划分函数的联盟博弈,并采用基于粒子群优化算法对传输功率进行优化,进而规划提出了具有功率分配的基于联盟形成的子信道分配算法(Sub-channel Allocation of Coalition Formation Game with Power Allocation Algorithm,SCFG-PA),并证明了该算法所形成的联盟总能收敛到一个纳什稳定的联盟结构。3)提出了基于重叠联盟形成博弈的Small Cell网络子信道及功率分配方案。运用重叠联盟博弈的相关理论对Small Cell网络中的子信道资源进行分配,并设计了一个多目标优化的方法,即同时最大化网络中的总数据速率和最小化Small Cell基站的总传输功率,并借助于加权求和的方法得到最优解。进而在本论文中设计的开关转换规则及独立规则的基础上,提出了具有功率分配的重叠联盟博弈算法(Overlapping Coalition Formation Games with Power Control,OCF-PC),证明了该算法的收敛性及稳定性,并通过相关仿真实验证明了该算法的优势。4)提出了基于分层式联盟结构生成的密集Small Cell网络干扰管理方案。针对楼宇环境中Small Cell基站超密集部署引起的同层干扰问题,以提升Small Cell基站形成的联盟的系统容量为目标,采用分层式联盟结构生成理论进行数学建模,从理论上得出了该方案的最优联盟结构,进而提出了适用于密集Small Cell网络下行通信系统的基于分层群集及联盟结构生成理论的干扰管理方案,即基于分层群集的 Small Cell 基站合作的算法(SBSs Cooperation Using Hierarchical Clustering Algorithm,SC-HCA),证明了该算法的收敛性和复杂度,并通过一系列相关仿真实验,从不同角度证实了该算法的有效性。综上所述,本论文对Small Cell网络中基于联盟形成的资源分配及干扰管理技术进行了较为深入的研究与分析。通过运用联盟博弈、重叠联盟博弈以及分层式联盟结构生成理论,分别针对Small Cell基站部署稀疏和稠密的两种场景下的网络系统特点,对网络中的资源分配及干扰问题进行合理的数学建模,在一定程度上有效解决了 Small Cell网络所面临的问题。所提出的解决方案对于Small Cell网络的进一步发展具有重要意义。更多还原

【Abstract】 The rapid growth of mobile data traffic and the number of mobile terminals and the development of all kinds of mobile services bring unprecedented challenge to the current communication system.In order to satisfy the development of the future mobile communication networks,it would be impractical to only depend on the existing network upgrade.Therefore,the next generation communication technologies,i.e.,the 5th generation mobile communication technologies(5G)have become a research hotspot at home and abroad since 2014.Since small cell networks and its ultra-dense development networks have many advantages,such as high capacity,universal coverage,low energy,flexible deployment and low cost,they have become one of the most important 5G technologies.Small cell networks are the wireless cellular network system and are composed of some small cell base stations whichhave low transmission power.By the widespread deployment of small cell base stations,ultra-dense networks(UDN)are formed and improve the system capacity,which will be a most effective solution in order to achieve the future 5G network goals,for example,a 1000-fold increase in data traffic and user experience rate for 0.1～1Gbps.However,the development of small cells pours into the strong vitality for the current communication networks at the same time causes the problems of resource allocation and interference which will have an adverse impact on system capacity and user experience.Moreover,the previous wireless resource allocation algorithms and interference management technologies cannot be completely applied to small cell network.Hence,how to allocate resource and manage interference is an urgent issue for the current communication networks.Based on the theoretical methods such as coalition game theory,probability theory,clustering algorithms and related optimization algorithms,this dissetrtation has done some investigation and research on the resource allocation and interference management for small cell networks.By the depth analysis of the characteristic of small cell networks and its difficulty and challenge,sub-channel and power allocation and co-tier interference mitigation schemes are proposed to improve the overall network system capacity from the perspective of small cell base stations’ coalition formation.The main work of the dissertation consists of the following:1)Coalition formation based resource allocation and interference technologies in small cell networks are expounded.This dissertation analyzes and discusses the differences between cooperative game and non-cooperative game,and delves into the competitive and cooperative behaviors of small cell users when they use wireless resource.Based on the existing literature which focused on resource allocation and interference management schemes in small cell networks,this dissertation explains the inevitability and feasibility of using coalition game theory to research resource allocation and interference management in small cell networks.2)Coalition formation based resource allocation scheme in small cell networks is proposed.For the characteristic of the downlink communication system in small cell networks,small cell base stations’ cooperation process is formulated as a coalition game in partition form with transferable utility.Meanwhile,in order to optimize the transmission power,the particle swarm optimization method is used.Furthermore,this dissertation proposes the sub-channel allocation of coalition formation game with power allocation algorithm(SCFG-PA)and proves that the formed coalitions always converge to a Nash-stable coalition structure.3)Overlapping coalition formation based sub-channel and power allocation scheme in small cell networks is porposed.By using the overlapping coalition game theory,sub-channel resource in small cell networks is allocated and a multi-objective optimization method is designed,i.e.,the maximum total data rate and the minimum total transmission power are obtained simultaneously by the weighted sum method。Furthermore,on the basis of switching order and independent order,the overlapping coalition formation game with power control(OCF-PC)is proposed and its convergence and stability are proved.The advantage of the proposed algorithm is also confirmed.4)Hierarchical coalition structure generation based interference management in small cell networks is proposed.To solve the co-tier interference problem caused by the deployment of ultra-dense small cell base stations in the indoor environment and to improve the system capacity,small cell base stations’ cooperation problem is modeled as a hierarchical coalition structure generation.The optimal coalition structures are obtained.Furthermore,the interference management scheme is proposed for the downlink transmissions in a small cell network,i.e.,SBSs Cooperation Using Hierarchical Clustering Algorithm(SC-HCA).The convergence and complexity of this algorithm are proved.By the series of simulation experiments,the validity of this algorithm is confirmed from the different perspectives.In conclusion,this dissertation carries out a deeper research and analysis in resource allocation and interference management technologies which are based on coalition formation.By applying coalition game,overlapping coalition game and hierarchical coalition structure generation theory,we consider the two scenarios,i.e.,the sparse and dense developments of small cell base stations and conduct rational mathematical models.Some problems in small cell networks are solved to some extent.The proposed schemes are significant in the future development of small cell networks.更多还原