Network Formation in IEEE 802.15.4e Networks An Optimal Beacon Allocation Algorithm

In this thesis we focus on network formation process in sensor/actuator networks using IEEE 802.15.4e Time Slotted Channel Hopping (TSCH). That is strongly influenced by the policy used by nodes to transmit EBs (Enhanced Beacons), i.e., special messages used to announce the network presence. The standard doesn’t define any specific ad- vertising policy. However, defining a ‘proper’ advertising policy, i.e, deciding when and how EBs must be sent, is very important since joining nodes have to keep their radio ON, while waiting for an EB. It follows that the network formation process can be very energy hungry and may limit network lifetime if not performed properly. In this thesis we propose a Model-based Beacon Scheduling (MBS) algorithm to handle the transmission of EBs in IEEE 802.15.4e TSCH networks. MBS aims to minimize the average joining time, i.e., the average time a nodes takes to join the network. To this end, it relies on a Discrete Time Markov Chain (DTMC), model of the network advertising process, and on solving a Mixed Integer NonLinear Programming (MINLP) problem. We compare by simulation the performance of MBS with that of other previous algo- rithms proposed in the literature. Our results show that MBS outperforms previous proposals in a number of different scenarios