An Adaptive TDMA based MAC Protocol for Mobile Wireless Sensor Networks

Radio transceivers for wireless sensor networks are typically cheap devices offering low bandwidth communication only. When physical events in the real world trigger spontaneous communication in many nodes the single communication channel is under heavy load and many messages are lost due to collisions. CSMA/CA schemes are well suited to spontaneous communication, but do not provide a high channel utilization under heavy load. TDMA protocols have some conceptual advantage here, but in the case of mobile sensor nodes they need to be adaptive and establish TDMA schedules on demand. MLMAC is a novel TDMA based MAC protocol that can react on changing radio neighborhoods in mobile networks. In this paper we introduce the MLMAC protocol and present the results of real experiments with a group of mobile sensor nodes based on RCX robots.