Research On Vertical Handoff Algorithm Based On User High Speed Mobility In Ultra-dense Network

With the continuous development and innovation of communication science and technology,the communication mode of the single communication network within the original coverage will gradually fail to meet the needs of users.Therefore,in order to meet the user's growing communication demand for the future network,the future communication network will gradually develop toward the direction of multi-network convergence and ultra-intensive coverage.In order to ensure the communication effect of multi-network convergence in the future ultra-dense network architecture,and each communication network can provide communication services for users in an orderly manner,so the vertical handover technology which could offer the efficient and reasonable handover in the future ultra-dense network has an extremely important research and learning implicationsFor the vertical handover technology of heterogeneous networks,the current academic and industrial circles have proposed different solutions from different angles,but the research and application of efficient vertical handover algorithms for future ultra-dense heterogeneous network coverage architecture is now the blind spots of the research,and the traditional heterogeneous network vertical handover algorithm often do not consider the high-speed mobile characteristics of the user,so the traditional heterogeneous network vertical handover technology cannot be applied to the future ultra-dense heterogeneity of users with high-speed mobile characteristics.In view of the shortcomings of the above-mentioned traditional vertical handover technology,this paper intends to study a kind of efficient vertical handover algorithm which is suitable for the ultra-dense network in the future.The vertical handover algorithm is divided into a network selection process and a handover time selection process,and corresponding network selection functions and handover time selection functions are respectively given for the above two sub-processes to construct a complete vertical handover algorithm.In the network handover process,a network handover function based on the Asynchronous Advantage Actor Critic strategy which considers the user's own high-speed mobility is proposed under the future ultra-dense network architecture.In the process of constructing the network selection function,the influence of the user's mobility on the network parameters and the different requirements of the differentservice types on the network parameters are considered to construct a personalized weight value sequence.Then,the network state is modled by Markov,and the system could calculate the return values of different strategies to output the optimal network switching strategy.At the same time,in order to more effectively ensure the efficient implementation of the algorithm,the asynchronous calculation method is adopted,and the massive communication data brought by the future ultra-dense network can be properly handled on the basis of ensuring a certain calculation delay.In the handover time selection phase,the high-speed movement characteristics of the user under the current ultra-dense network coverage are incorporated into the construction process of the handover time selection function by means of fuzzy logic.The user's first vertical handover moment is determined by monitoring the user's return value in the current network,and then the different fuzzy logic levels are divided for the users of different moving speeds by the improved triangular membership function in the fuzzy logic,after that the corresponding handover time points set could be obtained.thus completing the construction of the entire handover time selection function.Finally,according to the handover selection function and the handover time function,a vertical handover algorithm which is suitable for ultra-dense heterogeneous network architecture considering the high-speed mobile characteristics of users is obtained.Simulation experiments show that the vertical handover algorithm proposed in this paper is better than the comparison algorithm for the return value,average blocking rate and average handover times of different users and different service types under the same conditions.Therefore,under the ultra-dense network architecture,the heterogeneous network vertical handover algorithm proposed in this paper can effectively improve the validity and accuracy of network handover and improve the communication quality of users based on a certain computational delay.