Neighbourhood monitoring for decentralised coordination in multi-agent systems: A case-study

Decentralized coordination of multi-agents requires that every agent reliably and efficiently disseminates its state to neighbours through a wireless network. If dissemination is unreliable, safety issues may ensue. Unfortunately, the broadcast service of wireless network is efficient but unreliable (e.g., IEEE 802.11). The Neighbourhood Monitoring Protocol (NMP) is an efficient and scalable protocol that assures a reliable state dissemination between mobile agents, under some conditions of channel utilization. NMP runs on top of IEEE 802.11. In this paper we evaluate NMP with a specific decentralized collision avoidance algorithm based on the GRP policy. The algorithm is particularly challenging because it accommodates an arbitrary number non-holonomic agents. We show that NMP allows the system to scale well and provides a very high state delivery ratio even if it operates on the unreliable broadcast service like 802.11. Doing so, NMP assures the correct state information to the collision avoidance algorithm.