Design and implementation of out-of-band signaling for seamless handover in wireless overlay networks

An out-of-band basic access signaling (BAS) protocol is introduced for use in heterogeneous wireless networks. The BAS protocol enables a mobile terminal to communicate with an agent in a fixed network through any radio access network (RAN) chosen by the user as the basic access network (BAN). The agent uses the information on the location of mobile terminals and on the availability of RANs to decide which RAN to use, taking the user´s preferences into account. This protocol was implemented in a demonstration system using existing radio systems and the standard mobile IP protocol. The separation of the signaling path from the data paths was found to save energy and to facilitate handover between RANs.