LL-MAC: A low latency MAC protocol for wireless self-organised networks

This paper proposes LL-MAC, a medium access control (MAC) protocol specifically designed for wireless sensor network applications that require low data latency. Wireless sensor networks use battery-operated computing and sensing devices and their main application is environmental monitoring. In order to achieve such requirements, the whole network must work autonomously and collaborate in periodically sensing the surrounding environment and sending data to the sink. LL-MAC uses novel techniques to offer a low end-to-end data transmission latency from the furthest away nodes to the sink in a unique working cycle while offering a low duty cycle operation in a multi-hop fashion. Key features of this protocol include a synchronised sleep schedule to reduce control overhead along with a mechanism to avoid overhearing unnecessary traffic and elude collisions. Finally, control interval adjustment enables power-aware topology management in changing environments.