Implementation of a Collection Tree Routing Protocol and a Predictive Outage Compensator

Abstract: Wireless communication is widely used in modern devices but has not yet conquered industry. Introducing wireless control in industry will result in an economical bene t since installing cables is time consuming and expensive. Wireless control brings other problems to the table such as delays and packet loss which are discussed in this thesis. The original problem scenario is set in an industry with wireless control loops. A fork lift parks in a way so that communication on a wireless path is broken, creating a so called communication outage. Two solutions to this problem are proposed. The first contribution of this thesis solves the communication outage by re-routing. The solution is a Collection Tree routing Protocol (CTP) that detects the broken link and nds another way of sending the information. This solution proves to be eective as only between one and eight packets is lost. The implementation of this protocol is implemented on wireless communication modules called Tmote sky motes. The second contribution deals with lost packets. A Kalman lter based Predictive Outage Compensator (POC) is introduced and implemented on a Quanser Two Tank process together with the routing protocol above. The POC is benchmarked against a naive and commonly used Hold compensator that simply holds the last received value. Results show that the Kalman POC eectively estimates lost information where the Hold compensator causes over ooding of the water tanks.