Dynamic water gate assignment scheme for data aggregation in long-thin sensor networks

The long-thin (LT) network topology is promoted for many deployments of wireless sensor networks (WSNs) due to the application requirements. An LT topology consists of long branches of sensors, where each sensor has only one potential parent toward the sink. Data aggregation may help reduce excessive packet contention, but constraints imposed by the maximum payload size of each packet severely limit the amount of sensing data that can be aggregated along a long branch of sensors. Therefore, the paper suggests that multiple aggregation nodes, called water gates, should be designated along a branch to aggregate sensing data sent from their upstream sensors. Then, we develop a dynamic water gate assignment scheme that reduces the response time while avoids network congestion for data collection in LT WSNs, which can accommodate the time-varying sensing data generating rates of sensors. A testbed of 100 sensors is deployed and experimental results demonstrate the effectiveness of our scheme.