ripple flooding in wireless sensor networks
Flooding is a fundamental operation to support route discovery and time synchronization in wireless sensor networks. A simple flooding causes the broadcast storm problem and leads to long latency to complete the broadcast. This paper presents the Ripple flooding scheme (RFS) for wireless sensor networks (WSNs). The proposed scheme improves the convergence speed of flooding by using a synchronized packet rebroadcasting instead of using a CSMA (Carrier Sense Multiple Access) MAC based packet rebroadcasting. We analyse the multipath delay spread feasibility on a receiver for the packets from multiple senders. The theoretical upper bound of packet loss rate (PLR) is less than 13\%. The experimental result shows the same as the PLR of the theoretical analysis. We implement the RFS on the sensor node with the MSP430 microcontroller and the CC2420 transceiver and evaluate the major performance metrics including the convergence time and the reliability in various network scales and densities. The convergence time is at least 3.5 times faster than the CSMA MAC based flooding in the dense network environments. The transmission reliability of the RFS is slightly better than the reliability of the CSMA MAC based flooding because of the implicit overhearing scheme provided by the RFS.
flooding sensor networks broadcast convergence time