Mobile Communication Middleware Supporting Virtual Home Environment

摘要

This paper describes the seamless communication platform for mobile user over different kind of networks. The platform also enables user to customize his/her service depending on the current communication devices, time, places and occasions. For this purpose, we propose a multi-agent solution where independent software module interacts with each other through common agent communication language. There are several kinds of agent such as personal agents, network agents, and radio agents which are constructed on our Java-based agent library called Kafka-Pathwalker. Users can access their personalized service through these agents from any access point over the network. This function is generally called virtual home environment (VHE). Our system is an implementation of VHE using a multi-agent model and a user-level location management. A personal agent provides its end-user with an abstract view of communication services and a user customized service. The personal agent keeps track of the current location of each user and determines the optimum communication devices to be used. A network agent, on the other hand, provides a seamless view of various communication channels by using proxy techniques. The client-side network agent resides in the mobile device and automatically selects the optimum communication medium among available network channels according to the end-user's routing policy managed by the personal agent. It also reconfigures the network environment automatically. The server-side network agent cooperates with the client-side network agent to hide the instability of the wireless channel and the available bandwidth of the actually selected network channel for the user. This function is executed by a radio agent which terminates TCP/IP protocol and manages the light weight protocol supporting automatic re-connecting function. First, we clarify the requirement for supporting VHE service, then propose our solution based on multi-agent architecture. Next, we describe the mobile communication middleware, which consists of two layers of application and network adaptation. We also show our prototype system developed for evaluating the feasibility and performance of its elementary function.