On the MAC Protocols of Co-Existing Time-Slotted Sensor Networks

Report, 2007

We consider a joint scheduling approach for clustered sensor networks, where clusters use a time-slotted mechanism to access a shared medium. It is shown that a significant increase in packet delivery probability can be achieved if the transmission schedules at neighboring clusters are considered jointly. In our consideration of the problem, we include realistic propagation effects, such as Rayleigh fading, something that is often neglected in the literature. For networks with more than two clusters, the scheduling problem is NP-hard, and we therefore approach the problem using Lagrangian relaxation methods. A numerical evaluation of the proposed algorithm show that gains in packet delivery probability up to thirty percent can be achieved over a random scheduling.