Design And Implementation Of Virtual Terminal System In Heterogeneous Network Environment

In order to meet the diversity demand of terminal business in future, heterogeneous network has become the hotpot in the research of current wireless network. Heterogeneous refers to two or more wireless communication system integrate mutually, which belong to different operators, use different access technologies, having different coverage or with different bandwidth. Through the integration of the existing wireless communication system, taking advantage of the comprehensive advantages of multi system can effectively satisfy the future demand of mobile communication business. By using terminal aggregation and reconfiguration to provide unified service for the user, which can fulfill all aspects of demand of users in the heterogeneous network environment, such as the quality of service, transmission rate, safety performance and user experience.A multi-stream concurrent transmission system based on multi-terminal coordination system is described at first, it has four parts, including service server, service client, network management control server and virtual terminal system, which four parts are briefly introduced and analyzed respectively. Then a virtual terminal system is designed and implemented to provide users with intelligent business. The main contents are as follows:(1)Due to the importance of virtual system in service transmission, the design of virtual terminal system is emphatically introduced. First, the system work with Ad-Hoc mode, so using AODV routing protocol can establish multi-hop communication between the terminal equipment which with remote distance. Then giving the detailed specific steps of terminal controller and terminals in the process of terminal discovery, terminal aggregation and terminal reconfiguration.(2)Based on the detailed design, the specific implementation process of the virtual terminal system is discussed. Thanks to the stable, efficient and modular design features of Linux system, this system choose the Tiny6410 ARM board of friendly arm as the platform for system terminal equipment. Also by selecting wireless network card which support Ad-Hoc mode and transplanting the wireless drivers to the terminal device platforms can load and unload the wireless driver on the ARM board dynamically. Then we program the routing protocols and cross-compiler the executable file on ARM board. At last, we do software programming by refering to the function of the terminal controller and the terminal, including the realization of QT interface、socket and multithreaded programming and so on.(3)Finally, multi-hop communication, terminal discovery, terminal aggregation and terminal reconfiguration are validated according to building experimental platform. Experiment results show that the virtual terminal system is not only can’t be affected by the coverage limits of AP but also can expand the aggregation scope effectively. Using multi terminal aggregation to provide service to user can greatly improve the transmission rate of the business. Besides, achieving the terminal reconstruction adaptively through the selection of the network can ensure to provide the best service currently and improve the user experience effectively.