| With the development of wireless mobile communication technology,the future mobile communication network will be a heterogeneous converged network in which multiple access technologies coexist,cooperate and complement each other.At the same time,due to the popularity of mobile smart devices and applications,and the development of multimedia services such as live broadcasts,users' demands for data traffic and mobility are increasing.This obviously requires the integration of various wireless technologies to enable smooth and seamless handover across various technologies to ensure a better user experience.The traditional vertical handover algorithm considers fewer parameters and lacks a comprehensive evaluation of the network.At the same time,there are many factors affecting the handover result,and the handover itself has strong uncertainty.Different algorithms use different network parameters and different ways of processing parameters,which directly affect the quality of the handover results.Furthermore,the existing literature pays less attention to the handover execution phase and lacks a handover mechanism to implement the proposed algorithm.This thesis absorbs the advantages of existing algorithms,proposes a vertical handover algorithm based on fuzzy logic,and at the same time develops a suitable handover mechanism to implement the proposed algorithm.Firstly,the traditional algorithm has the problem that only the received signal strength value or other common factors are used as the decision parameters,resulting in less information and higher handover failure rate.This thesis uses hierarchical filtering,comprehensive multi-parameter features,and combine with the moving speed of the mobile terminal to give the final Provide a reference for decision making.Secondly,in order to clarify that mathematics can't deal with the uncertainty information,this thesis uses the fuzzy logic method to fuzzy divide the network parameters that cannot be specified in the specified range,and input the fuzzy logic decision module to obtain the network comprehensive performance value(NCPV).The algorithm makes a handover decision based on the NCPV.The simulation results show that the algorithm reduces unnecessary handover and avoids the ping-pong effect.Finally,this thesis proposes a handover mechanism based on Multipath Transmission Control Protocol(MPTCP)under the Software-Defined Networking(SDN)architecture.This mechanism evaluates the network status from multiple angles based on the acquired multiple network parameters.At the same time,this thesis also researches on the combination of SDN and MPTCP protocol,so that the proposed fuzzy logic algorithm can be effectively used in the relevant network architecture.Simulations show that this mechanism achieves true seamless handover. |
