A Smart Multichannel Slotted Sense Multiple Access Protocol for Industrial Wireless Sensor Networks

Wireless sensor networks (WSNs) can be used for monitoring and control applications in which a server collects data from a work field and provides a service based on the analysis of those data. Such applications require a timely service as well as a reliable data transmission. A smart multichannel cross-layer protocol is proposed that can satisfy the requirements of industrial WSNs. When every sensor node should send data to a server periodically, the protocol not only shortens data acquisition cycle time (DACT) by allowing parallel data transmission using multiple channels but also improves the reliability by avoiding the collisions of control messages using a smart CSMA mechanism. This also can resolve the well-known chronic WSN problems, such as the hidden node, exposed node, and false blocking. In addition, the proposed protocol is reinforced by an adaptive routing and channel selection scheme to improve the reliability of data transmission under the presence of multipath fading, external interference, and industrial noises. By simulation and analysis, it was proven that the proposed protocol could improve DACT, packet delivery ratio, and energy consumption considerably, compared to other protocols. Furthermore, the protocol was successfully applied to a process monitoring system of a smart factory with high reliability in data transmission and a small DACT.