Study On Energy Efficiency Mechanism Of Femtocell Sleeping Technology In Qoe-Oriented Hwns

In recent years,the rapid development of wireless communication technology has exerted significant influence on human life and the development of society.The energy problem is a serious problem in various countries and industries,therefore,developing green communication is an effective measure to realize the sustainable development of communication systems.At the same time,with the increasing demands of users for multimedia,video and other services,the QoE of users' experience quality is one of the most important indexes to measure the performance of wireless communication systems.Currently,the heterogeneous wireless networks(HWNS)which can provide high data rate and diversity services for users become the mainstream development trend of mobile communication systems.The thesis aims at the scene of a two-layer heterogeneous network composed of macro base stations and femtocell base stations,and the femtocell base stations sleeping is the main technical scheme to realize the optimization target of improving the energy efficiency and ensuring the QoE level of the users.Firstly,this thesis puts forward a micro base stations sleeping technique which based on QPSO algorithm.The QPSO combines the advantages of the Particle Swarm Optimization and the Quantum Evolutionary Algorithm,which can quickly and accurately solve the complex optimization problems.In order to improve the energy efficiency of the systems,some femtocell base stations need to enter sleeping mode which is determined by the iterative search strategy of QPSO algorithm.The simulation results show that the QPSO search algorithm can effectively improve the energy efficiency of the systems under the precondition of guaranteeing the users' QoE by setting the learning factors and the weight coefficient reasonably.Afterwards,considering the energy efficiency optimization problem of dynamically distributing the base stations' sub-channel power,this thesis combines the power allocation scheme of the base stations' sub-channel with the technology of femtocell base stations sleeping,and then the iterative solution named ESPA algorithm is designed.With the help of Lagrange function to solve the optimal objective function with the inequality constraint,this thesis obtains the scheme of combining femtocell base stations sleeping with power allocation of the base stations' sub-channel.By comparing the simulation results,the superior performance of ESPA algorithm is highlighted.Aiming at different angles of Energy efficiency optimization,the thesis puts forwards the corresponding algorithm scheme which can effectively improve the energy efficiency of the systems under the precondition of guaranteeing the users' QoE level.Simulation results show that the proposed algorithm is effective and feasible,and the expected optimization target is achieved perfectly.