Interference Management Scheme In Dense Small Cell Networks

Densely deployed Small Cell Network(SCN)is a promising approach to improve network capacity for the 5G communication system due to the high link quality,low power consumption,low cost and high spectrum efficiency.Dense Small Cell Networks can be randomly deployed in hot spots to provide service.The transmission rate can be improved effectively as the distance between base stations and user equipments is decreased,thus improving the throughput of the network.However,Due to the dense deployment and fully frequency reuse among cells,the cell-edge users suffer serious interference from adjacent cells.On the other hand,it is hard to meet the increasing data services with limited spectrum resource.Therefore,it is crucial to make efficient interference management and improve the utilization of spectrum resources for developing the Small Cell Network with excellent performance.In this thesis,we focus on the inter-cell interference problem in densely deployed Small Cell Network scenario.To mitigate inter-cell interference and improve transmission quality,Coordinated Multipoint Joint-Transmission(Co MP-JT),which allows multiple senders to transmit concurrently,was developed.On the other hand,we consider that Co MP technique comes with the cost of high backhaul capacity demand for data exchange between the core network and Small Cell Base Stations(SBSs),we combined with Co MP and content caching to solve the interference problem,meanwhile,reducing backhaul resource consumption.Four aspects are mainly studied: 1)The transmission mode selections.2)Make decision of user access.3)Optimize the backhaul resource based on content caching.4)The resource allocation problem is investigated to ensure users' service quality.A joint optimization of user association,transmission mode selection and content caching is firstly studied to minimize the backhaul resource consumption while guarantee the requirement of spectral efficiency.To solve the joint optimization model,we divide the problem into two sub-problems.One is the user access joint transmission mode selection problem.The other is the content caching problem.An algorithm based on load balancing is designed to solve the user access and transmission mode selection problem.By balancing the traffic load between cell,the spectrum resources can be fully utilized.Then,we solve the content caching problem in a distributed manner based on backtracking algorithm.The resource allocation problem in Small Cell Network is then studied.We develop a joint optimization model of access resource allocation and backhaul resource allocation to minimize the total transmission delay of the system,while avoiding the co-channel interference.We divide the joint optimization mode into two sub-problems: access resource allocation and backhaul resource allocation.The corresponding greedy algorithms are proposed to solved the two subproblems.The simulation results show that the proposed algorithms can effectively reduce the transmission delay and meet the service requests of users.