Research And Implementation Of Vertical Handoff Algorithm In Heterogeneous Wireless Networks

With the rapid development of communication technology,there are various wireless access technologies,and multiple wireless networks exist at the same time.Different wireless networks have different performances in terms of transmission bandwidth,delay,cost,coverage,etc.And none of these networks can simultaneously satisfy high bandwidth,low delay,low cost,and wide coverage.So it is an inevitable trend to achieve convergence and interworking of heterogeneous networks and switch to the appropriate network at any time according to the needs of users.The vertical handoff technology is the basis for heterogeneous network convergence and interworking,and it is the core technology that supports the seamless convergence of different networks.First,we introduce the background and research of heterogeneous wireless network briefly,and then classify the common vertical handoff algorithms to different types and summarize their characteristics,applicable scenarios and deficiencies.Based on these research,we propose two vertical handoff algorithms as follows:Considering most of previous researches on vertical handoff algorithms make an always-best-selection rather than always-suitable-selection,we propose a vertical handoff algorithm based on FAHP-MGRA.In order to comprehensively consider the network conditions,user preferences and avoid the influence of unreasonable weights,we use FAHP to calculate the weight of each network parameter.And then,each candidate network is ranked by MGRA to select the most appropriate candidate network.Most of previous researches on vertical handoff algorithms consider mobility users` payoffs only.These algorithms focus on user`s network requirements,user preferences and QoS in vertical handoff process and ignore network providers` payoffs.So we consider the network selection process as a game model,and propose a vertical handover algorithm based on non-cooperative game theory.We comprehensively consider the interests of mobile users and network operators in the game process.We simulate the two vertical handoff methods we proposed in the OPNET network simulation environment.The simulation results show that compared with the traditional vertical handoff algorithms,the algorithms we proposed can effectively avoid the ping-pong effect and fully consider the user preferences and network conditions.During the process of our simulation,the algorithms we proposed select the most suitable networks.