Seamless mobility across heterogeneous wireless domains

In recent years, wireless communication technologies have been pervasive. We have many wireless options to connect to the Internet: IEEE 802.11 WLANs, GPRS, UMTS and many other competing technologies. These wireless standards were designed independently of each other. Hence, these standards do not specify a common solution to perform connection handover between two different standards. Given that each of these standards has its own advantages and disadvantages, users may want to use the best available connection for their needs. In this paper, we propose a scheme that enables seamless transitions between different wireless standards through SIP protocol. With our scheme, IP mobility across both vertical and horizontal handovers is possible without any modification to the existing applications. We define a guideline for handovers between networks, and then perform experiments with our scheme implementation to confirm the feasibility of our proposed scheme. Our results show that with our scheme, connection disruption is minimized.