Adaptive time slots control in wireless sensor networks for delay-aware applications

Wireless Sensor Networks (WSNs) have been proposed for various monitoring applications including environmental, industrial, military and health care. The use of WSNs with cluster-tree topologies for such applications solves the limited coverage issue of the wireless sensor devices and allows them to be deployed in wider area. WSNs with cluster-tree topologies suffer from various problems including accurate synchronization of beacons used in the beacon enabled mode in the IEEE 802.15.4 standard and providing Quality of Service (QoS) to delay-aware applications. In this paper, we present a Time Slot Control (TSC) scheme that can adaptively manage the allocation of time slots in the beacon enabled mode of operation to provide QoS grantees to delay critical traffic. Our proposed scheme can improve the end-to-end delay and throughput of selected traffic types by managing the time slots between sensor devices in an optimum way.