AWS: asynchronous wakeup schedule to minimize latency in wireless sensor networks

We propose a novel approach to design an asynchronous wakeup schedule (AWS) for the radio of the nodes in wireless sensor networks, in order to reduce the end-to-end latency with energy efficient data transmission. Each node is assigned a particular color and the process is repeated for grouping the nodes based on graph coloring of vertices. The wakeup schedule of a node's radio is fixed based on the color assigned to that particular node. Each node maintains a forwarding table, which contains the color information of the neighboring nodes. When a data packet has to be transmitted, active neighbor discovery is done using the forwarding table, which helps to find out the neighboring node that becomes active sooner so that the packet can be forwarded with minimum waiting time, which reduces the overall end-to-end latency. Simulation studies indicate that the proposed protocol is quite effective under various network characteristics, such as node density, number of colors, and hop distance when compared to other protocols such as SMAC and AWAN