Aalborg IPv6 Radio Project

WING The TCP/IP protocol suite, already widely used over fixed data connections is also increasingly applied over wireless connections. However since it was never developed for use within this domain several degrading factors exist, such as: the lack of mobility management mechanisms, the inability of the congestion control mechanism to function over links with a higher error probability (for example wireless links), and the need for guaranteed levels of service and security. The Aalborg IPv6 Radio Project focuses in particular on the offering of Quality of Service over these wireless packet networks given the fact that the link quality varies as well as the users and their offered traffic with the network. The research within the project focuses at the moment on cross-layer optimisations in order to improve the offering of Quality of Service in (IP based) packet switched networks. Based upon the monitoring of the incoming traffic (quantity and desired service level) and the available radio resources the most appropriate logical link is defined in terms of Error Correction coding, maximum number of re-transmissions, frame size to optimise for a certain delay or throughput. Further the project has investigated mobility extensions to IP, such as Mobile IP and Hierarchical Mobile IP. These mechanisms reroute the packets if a user is not available in his home network but resides somewhere else. The delay, overhead and possibilities to offer Quality of Service vary per method and depend on for example the frequency by which the roaming mobile updates location databases and how transparent handovers are implemented. (Carl Wijting)