Performance issues and modelling of mobile executed handoffs in multispot beam dynamic satellite networks using ATM multiplexing

We present a study on some performance characteristics of future mobile satellite networks that use ATM technology and examine possible ways of handling the user mobility related issues. In dynamic constellation satellite networks, the mobile terminal movement in respect to the satellite movement can be neglected for the majority of the users. However, parameters like the call duration and the constellation statistics, are directly associated with the possible number of hand-offs that each mobile station will experience to adjacent spot-beams or even to other satellites. The aim is to reduce the call dropping probability due to handover by introducing a reservation based mechanism that takes the system state and the connections to the adjacent spot beams into account. Our approach is based on the methodology for "mobile executed hand-off" that has been proposed for the wireless ATM in a pico-cell environment, and its applicability to the dynamic satellite networks is discussed. Using this technique the requirement for the switch setting rearrangement is minimised and the handoff control protocol can be simplified. Finally, a simulation model and some results of the call dropping probability and the call blocking probability under different traffic load conditions are presented.