Research On Access Selection Algorithms In Heterogeneous Wireless Networks

With the rapid development of mobile Internet in recent years,wireless access technology is becoming increasingly colorful.Increasingly,people are realizing that the demand of users is changing.It is impossible for an access technology to meet the requirements of all scenes and all users.The integration of heterogeneous wireless networks is an important development trend of the next generation of wireless networks.Under the background of heterogeneous network integration,it is necessary to use and manage the existing wireless network resources.The network access selection algorithm can select the most suitable access network for users,so it is also a research focus in the resource management of heterogeneous wireless networks.This thesis studies the network access selection algorithm under heterogeneous network fusion,which aims to meet the diversified QoS requirements of the user's business applications and maximize the utilization of network resources.The main contents are as follows:Firstly,the theoretical knowledge and background of heterogeneous network convergence are studied.Secondly,the theoretical basis of heterogeneous wireless networks is studied.Thirdly,the vertical handover execution architecture of heterogeneous wireless networks is studied.Then the relevant theoretical knowledge of heterogeneous wireless resource management is studied,and the relevant theoretical basis of access selection strategy is studied,which include some classical vertical handoff and accessing selection algorithms.In this thesis,a heterogeneous network selection algorithm based on multi services and synergetic theory is proposed.In heterogeneous network,how to select the appropriate decision parameters according to the characteristics of different services and use these parameters to select the most suitable network to reduce the blocking rate and increase throughput is a question.The algorithm regards the terminal selection network as a systematic problem.Each candidate network is considered as a complex system which is composed of several subsystems.The subsystem is composed of the corresponding network attributes.The entropy value of the composite system is obtained according to the concept of Shannon information entropy.The entropy value reflects the direct synergy of the subsystem,and then reflects the overall performance of the network.Secondly,the final switching target network is selected by adding the load decision module and combining the load of the network with the best collaboration degree and the cooperation degree suboptimal target network before the handoff execution.The simulation results show that under the four businesses,the proposed algorithm can effectively reduce the handover blocking rate and improving the overall throughput of the network.With the progress of multi-mode terminal technology,the service quality of single mobile terminal access to multiple networks has gradually changed into reality.Therefore,a multi network access selection algorithm based on the ranking method of approximation ideal is studied.The algorithm firstly determines all available wireless networks according to received signal power from base stations and considering every subset of these networks as one network selection scheme.Then we calculate the aggregation attribute of every scheme to confirm the candidate network schemes which are limited by throughput and power consumption threshold.The matrix of multiple attribute decision making is built and the optimal scheme to access is determined based on cost function value of every network scheme by using TOPSIS algorithm with user preference.The distance between the optimal scheme and the ideal scheme is the nearest.Compared with the single-access network algorithm of same way,the simulation results show that the multi-access network algorithm can make the best of idle network resources and obviously improving user quality of service,user throughput,reducing power consumption per bit and price cost per bit,and keeping network load balance simultaneously.