Description: Recent trends in mobile networking show a large-scale emergence of multimode mobile terminals, with the capability to simultaneously connect to different wireless communication systems. The network operators are also following the same direction by deploying an increasingly diversified portfolio of wireless communication systems, all this in order to extend the coverage and the capacity of their networks.  One of the biggest challenges both operators and device manufacturers face in such a heterogeneous wireless environment, is how to support the seamless roaming of terminals between different communication systems. Different bodies and organizations have already taken steps towards developing new standards to facilitate inter-system handover mechanisms supporting standards like UMTS, WLAN, WiMAX and DVB-H. In this paper we present such a concept developed by the 802.21 working group of the IEEE. Based on simulations we developed in Network Simulator 2 (NS-2), we follow the distinct handover steps and make a set of baseline measurements of parameters like handover latency and packet-loss ratio.

Description: Recent evolution of the mobile technologies show the large scale emergence of multimode mobile terminals, with the capability to simultaneously or sequentially attach to conceptually different access networks. To cope with this, they require some abstracted framework for their management and control, especially in the case of intelligent selection between the various heterogeneous accesses. A solution to this issue, the Media Independent Handover Services, is being standardized as the IEEE 802.21. This draft standard has been studied and applied to the case of a B3G operator networks as a research topic in the EU-funded project Daidalos in order to enable seamless operation between heterogeneous technologies. This paper focuses on the seamless integration of broadcast technologies, in particular UMTS/MBMS networks, in the case when emergency information has to be delivered to a large number of mobile users. It describes an extension to the 802.21 framework which enables the dynamic selection and allocation of multicast resources and thus the efficient usage of the radio resources. The UMTS access is developed in the experimental software radio platform of EURECOM, and provides a direct inter-connection with an IPv6 Core Network, very close to the current LTE direction of the 3GPP. We describe here the additional Media Independent Handover primitives and how they are mapped to trigger the control of multicast (MBMS) resources in the UMTS network. This paper is introduced by the account of an on-the-road emergency situation, written as a showcase of the work performed in the EU FP6 research project DAIDALOS.