Research On Load Balancing And Energy Efficiency In Heterogeneous Cellular Network

With the demand for data traffic increasing,the traditional cellular network can not meet the network capacity and the service diversity.Heterogeneous cellular networks with the low-power nodes solve the problems.However,the new challenges appear in the process of deployment.The first challenge is the load balancing problem between the macro base station and the small base station.Due to the different power,more users communicate with the macro base station.As a result,the macro base station load is too heavy but the small base station is under load,which wastes the network resources.Secondly,the dense small base station also causes the network energy consumption increasing and it has an impact on the environment.Therefore,how to achieve load balancing and reduce the energy consumption of the network is a hot issue in current research.This thesis studies the implementation of load balancing and reduction of network energy consumption.Firstly,the thesis introduces related background of heterogeneous cellular networks and the thesis elaborates on related research in load balancing and the energy efficiency in heterogeneous networks.The deployment methods and model construction of heterogeneous cellular networks,the common load balancing technologies and network energy-saving technologies are highlighted.Then,aiming at the load balancing problem in heterogeneous cellular networks,the user association strategy based on the shortest offset distance of base stations is used.Modeling is performed through the spatial Poisson point process and the user classification is performed according to the offset distance between the user and the base station.So more users are associated with the small base station to implement load balancing between the macro base station and the small base station.In addition,the performance parameters of the network are derived,including the user coverage probability,the user traversal rate and the network energy efficiency.The simulation results show that the user association strategy based on the shortest offset distance can improve the performance of the network while achieving load balancing.Finally,a joint strategy based on the power control and the resource allocation are used for the problem of large energy consumption caused by the small base stations deploying densely.The coverage probability of each base station and the average traversal rate expression of the mobile user are derived in the closed access and open access modes.By adjusting the spectral partition coefficient and the small base station density ratio to maximize the overall network coverage probability and minimize the energy consumption.The simulation results indicate that the strategy can significantly improve the network energy consumption.