Introduction
One of the most promising visions for the 4th generation (4G) of mobile networking (also called “beyond-3G”) is based on heterogeneity, where multiple access technologies will be handled coherently over multiple domains including operator and user networks. Handover requests will likely be triggered not only by a decrease in signal strength, but also by other criteria such as cost reduction, network resource optimization over several access technologies, service related requirements, etc., making handover a critical and complex matter which process needs to be optimized. In order to support such a vision for 4G enabling a continuous growth in future mobile communications and networking, it is necessary to define concepts and functions for mobility among multiple dimensions: domain, multi-technology, multi-service, multi-device, multi-hop, multi-access, multi-cast, etc.
Taking a snapshot of today’s communication resources including cellular networks, fixed networks and a variety of other wireless networks, we recognise that resources are often present, but rarely available to the user in a coordinated and trivial-to-use fashion. The main cause is that existing access technologies are not harmonized enough, due to commercial reasons and today’s rather early stage in the era of mobile communications.
Still the various access technologies could be exploited together for serving the same communication process. Bicasting through multi-accesses may prevent service disruption, when the same data is sent through different accesses in a kind of high-level multi-access soft handover. Multi-access diversity may also be used to increase the overall throughput by sending different flows through different accesses. The user may profit by making the
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own access resources available to other users, e.g. thanks to agreements with an operator in order to set up a local access point. Personal Area Networks (PAN) may require to handover a session from one device to another, e.g. to obtain a better quality of service. Multi-hop architectures may represent a natural extension e.g. in PAN scenarios and peer-to-peer environments, leading to inter-route handovers. Inter-operator (inter-administrative domain) handovers would also be required in a user-centric and heterogeneous environment.
The Ambient Networks project aspires to cope with these issues, within the vision of future mobile communications (beyond-3G or 4G) based on heterogeneity. The Ambient Networks project is an integrated project co-sponsored by the European Commission under the Information Society Technology (IST) priority within the 6th Framework Programme (FP6). This thesis represents a result of work performed within Ambient Networks Working Group 4, which focuses on mobility management. The work has been performed within the ‘Solutions and Concepts’ research department of Siemens Mobile Communications (Milano, Italy). More information on the project are available at www.ambient-networks.org.
The first chapter shows analysis coming from existing mobility management solutions in the main areas of interest: cellular networks, short range wireless access, IP-based solutions. Chapter two gives an overview of the Ambient Networks project presenting its definitions, goals, architectural principles and innovative ideas. Chapter three illustrates definitions, concepts and functions for mobility management within Ambient Networks, highlighting the main research results. One main outcome is the Handover Toolbox with its related commands and functions, enabling to construct a handover in the way that best suits the specific requirements of the flow to be handovered. Chapter four focuses on implementation of the new proposed ideas, showing how
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mobility can be carried on within Ambient Networks and how the handover toolbox concept can be embedded within a practical realisation of Ambient Networks. The last chapter presents conclusions and possible future developments of this work.
