Adaptive Medium Access for Wireless Sensor Networks

This paper deals with ALS-MAC, a medium access control protocol for wireless sensor networks. ALS-MAC is a single channel MAC protocol suitable for location-aware networks. The protocol employs beacons to synchronize internode communications. Scalability and collision avoidance are achieved via contention-based advertising slots mapped to schedule-based transmission slots. ALS-MAC has two dedicated modes of operation for data intensive traffic which assign temporary priority to nodes with many or long buffered packets. Beacons and signaling frames are combined to reduce the collision and control packet overhead. We study multihop optimization schemes for non-regular topologies under ALS-MAC. Later, we investigate how the opportunity for power-efficient partitioning of the communication link scales with the packet length.