Mobility

Mobile communications is a key research topic in the future of Communication Networks, since it has become a central aspect of the lives of citizens. Due to rapid technological and societal changes, there has been a bewildering proliferation of technologies and services for mobile users. Mobile devices are increasingly widespread and are better equipped in terms of access technologies and services support. The introduction of LTE as the future of cellular network architecture evidences that broadband wireless networks are quickly evolving towards all-IP based networks. A more flattened network architecture for the mobile Internet is anticipated to meet the needs of rapidly increasing traffic from the mobile users and to reduce cost in the core network.

These entire factors have created a complex communication environment for both users and network operators. It becomes therefore of major importance to rethink mobility from out-of-the-box perspective in order to create user-centered and manageable communication infrastructures for the Future Internet. It is expected that movements across different network segments become transparent to the user, so that the network should be able to maintain service continuity independently of location and access media, enhancing the heterogeneity of today’s networks, technologies and devices.

Mobility is a strong research area in our group and then spans through several sub-areas:

  • Mobility in heterogeneous technologies, integrating wireless technologies (e.g. LTE) and considering the support of multi-hop relaying techniques to improve vertical handovers procedures by integrating IEEE 802.21 standard and enhance network discovery and selection based on Always-Best-Connected paradigm. This work has started in the European FP6 IST-DAIDALOS Project, and has continued in the European IST-WEIRD and ICT-HURRICANE projects, and lately in the QREN PANORAMA Project, the Innovation Program Project LTE-MOB from Portugal Telecom Inovação and the ICT Network of Excellence Euro-NF DINASTY Project.
  • Solutions for Fast Handovers over 802.11, addressing the development of pre-handover policies and mechanisms suitable for the preparation of security association agreements with neighbors before the actual occurrence of handovers. This work has started in the QREN PANORAMA Project with Portugal Telecom Inovação.
  • Exploiting network coding to decrease the disruption of the active sessions running during the handover and to develop resource allocation and decision algorithms to optimize the use of multihoming. This work has started in the Internal IT Projects SHOWNET and COHERENT.
  • The trend on flattened network architectures, the user-centric networks and the migration of content servers closer end-user lead us to develop a distributed and dynamic mobility management solution. A distributed solution requires the development of efficient anchor selection mechanisms, and the investigation of algorithms for self-organized mobility anchor placement, aiming to ensure system robustness to frequent changes. We also work on handover optimization, in which handover decision algorithms are being investigated to optimize users’ Quality of Experience. This work has started in the FCT UMM Project.