Optimizing the Data Acquisition Cycle Time of a Sensor MAC in Industrial WSNs

Abstract

To reduce the damage of people and properties in industry fields, the response time of a MAC protocol should be kept as small as possible. Among the solutions suggested by various MAC protocols, shortening the data acquisition cycle time (DACT) is considered as the most effective way of reducing the response time. However, a small DACT is often fails to provide the sensor nodes with a sufficient time duration to transmit their data packets in TDMA-based MAC protocols while it surely increases the degree of contention among the sensor nodes in CSMA-based MAC protocols. In summary, a WSN with a small DACT usually fails to attain the satisfactory level of data transmission efficiency in WSNs. On the contrary, a WSN with a large DACT incurs an excess delay in data packet transmission. Therefore, we propose an analytical study for calculating the expected size of time slots so that an optimized DACT can be found. Our optimized DACT is precisely suited to the level-order data transmission that greatly improves the data transmission efficiency in industrial WSNs. In simulation experiments, it is shown that the proposed approach attains a higher packet deliver ratio than that of other competing approaches.