The Research On Vertical Handover Scheme In The Environment Of Wireless Heterogeneous Network

Wireless mobile communication technology has obtained the development which progresses by leaps and bounds in recent years.Despite a variety of different wireless access technologies have appeared and formed a heterogeneous network environment,there was no single network could meet the different user demand perfectly so far.Therefore,in order to satisfy the requirements of the growing wireless resources,ensure people can access real-time high performance network,realizing the integration of these network technology,achieving global connectivity,have become the focus of researchers.In essence,one of the key ingredients to achieve the continuity of terminal service and enhance the user experience effect is the convergence of complex network.In the process of realizing heterogeneous network communication,vertical handover,the key technology of mobility management in network convergence,will be the research emphasis of this paper.Traditional single-metric handover decision algorithms,are not efficient and intelligent enough to reduce the ping-pong effect,which will influence the quality of service seriously.In this paper,the vertical handover decision algorithm in wireless heterogeneous networks was studied from the view of user requirement.Firstly,the characteristics of heterogeneous networks were introduced,and then the implementation process of vertical handover was defined,in the end,the performance of several commonly used handover decision algorithms were summarized systematically.Considering the multi-user and single business scenario,and the dynamic changes of network,this research presented a novel fuzzy logic handover decision algorithm which is based on the advantages of typical heterogeneous wireless networks.The proposed scheme was used to deal with some practical problems such as the network selecting and improve the network performance in the condition of without increasing computational complexity,to a certain extent.Taking into account the coverage range of LTE and WLAN,the former is wider but possess a relatively small transmission bandwidth compared to the latter.In such a heterogeneous wireless environment,according to the needs of users for different service types,a new vertical handover algorithm with the consideration of terminal speed is proposed,basing on the principle of mutual benefit of both network.The algorithm was consisted of three steps.Firstly,the candidate networks were screened according to the pre-decision strategy to make the candidate collection of networks more accurate.Secondly,the parameter weight was calculated through analytic hierarchy process,and the target network was selected by the cost function,both the user's preferences and the quality of network service were ensured successfully.Thirdly,the final handover was completed with the combination of speed limit and reduced the ping-pong effect effectively.Finally,the flow chart was exhibited to make the algorithm more intuitive.The research was conducted in the simulation environment of MATLAB in this paper.The simulation results showed that the proposed scheme exhibited good performance in terms of minimizing the unnecessary handovers,and balancing the whole networks resources so as to save the cost of system and improve the system performance.