Coalition Formation Based Resource Allocation And Interference Mitigation In Small Cell Networks

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.