Access control and handoff management in multi-tier multimedia wireless systems

In this paper new techniques are proposed for the handling of multimedia traffic in a hierarchical multi-tier system involving microcellular, macrocellular and satellite coverage. In this environment, efficient channel assignment and hand-off management techniques become critical issues to fully exploit the benefits of the multi-layered architecture. The traffic flow control between layers has to maximise the system capacity without degrading the traffic QoS. This task is particularly hard when in the presence of multimedia calls, which ask for large amount of bandwidth and are characterised by the combination of traffic of different nature. The proposed algorithms differ from the traditional ones as they adopt a multi-bearer transport approach to carry multimedia traffic over the air-interface, coupled with suitable strategies for the allocation of each traffic component at the best layer. This leads to better resource utilisation and multimedia QoS guarantees, while minimising new call blocking and hand-off failure probabilities.