Vertical Handoff Algorithm For Enhancing Performance And User Experience In Heterogeneous Wireless Network

In recent years,the rapid increase in the number of wireless end-users and wireless traffic has brought new challenges to the current wireless communication systems.Heterogeneous wireless networks,which are composed of heterogeneous networks with different access technologies,have enriched the access of users to network services.How to solve the problem of network handoff has become the key to guarantee the quality of service and user experience in heterogeneous wireless network.Users have different network service requirements in different communication scenarios.The high-speed mobile users such as vehicle terminals need to complete handoff decisions in a short time.The ordinary low-speed users are more concerned about the performance improvements brought about by handoff decisions.In this paper,firstly,we present a robust vertical handoff algorithm for high-speed users in heterogeneous vehicle networks;secondly,we present a cost-aware handoff algorithm for low-speed users to ensure user experience.Finally,the first two algorithms are user-centered,which cannot make the handoff behavior between users benefit the whole system macroscopically.A distributed optimal vertical handoff algorithm based on consistent message passing is proposed.The main works of this paper are as follows:1.In the vehicle heterogeneous network,a robust vertical handoff algorithm based on decision tree is proposed to solve the problem that noise interference is not taken into account in current vertical handoff algorithm based on decision tree,which leads to the problem of low handoff accuracy.Firstly,the false decision probability of the current algorithms is analyzed and given in detail.Secondly,the Kalman filtering algorithm is used to estimate the network attribute value more accurately.Again,a probability threshold interval method is proposed to do a twice detection to the situation of the attribute value which is near the threshold.Finally,simulation results show that the algorithm can reduces the probability of false error decision and the failure rate of handoff,and improves the quality of service of the vehicle terminal.2.Based on the requirement that users want obtain the most satisfied network services at a lower cost,a new cost-aware switching algorithm is proposed.Firstly,the model of user's service saturation is established according to the network transmission rate.Combined with the normalized network cost,the network handoff problem is constructed as a multi-objective optimization problem.Secondly,in order to reduce network blocking rate,the user's decision behavior is transformed to EI Farol bar problem.By solving the Nash equilibrium solution of this problem,we get the expected value of user service satisfaction.Finally,the original multi-objective optimization problem is transformed into a maximization problem,and the Pareto optimal solution of the original multi-objective optimization problem is obtained by solving the maximization problem.Simulation results show that the proposed algorithm improves the total throughput of the network and reduces the handoff blocking rate,and enhances the service experience of the user terminal.3.For users to make optimal handoff decisions,it is impossible to predict other users' behaviors,and no one can guarantee whether the users' overall handoff behavior is beneficial to the overall benefit of the global system.A distributed network handoff algorithm based on consistent message passing is proposed.Firstly,the optimal handoff allocation strategy under the current network state is analyzed.Secondly,the practical feasible solution is approximated from the ideal optimal solution based on greedy algorithm.Theoretical analysis shows that the proposed handoff result is the nearest optimal solution to the optimal allocation strategy.Again,by using the consistent message passing algorithm based on Paxos,the user can reach a multi-handoff-consensus without centralized control device.Finally,the experimental results show that the algorithm guarantees the handoff performance of users and improves the overall transmission rate of the system.