Improvement On Quality Of Service For Target Tracking System Based On ZigBee

Target tracking is a very attractive topic in the research of wireless sensor networks (WSN). It utilizes multiple sensors in the network to generate target related information to collaborate with each other to infer the location of the target to help make decision on control and tracking. Based on its advantage in terms of high accuracy, flexible deployment and better performance, it plays an important role in military defense and national security.Generally, target tracking system possesses limited resources, however, it still needs to guarantee Quality of Service (QoS) for the user. The system is battery-powered, so low energy consumption is the key point for the system to achieve long-term lifetime as to work for months or years in the isolated location, and when target appears, the network has to ensure real-time transmission to provide reliable data to the user to assist on decision-making. Therefore, the energy consumption and transmission delay QoS are valuable research point.In this thesis, the user's QoS is mapped to the sub-processes of target tracking from the perspective of sensor and communication network. Based on the mapping, the QoS guarantee method is proposed to satisfy both the energy consumption and transmission delay QoS by improving the transmission protocol of the network.Furthermore, a popular communication standard ZigBee is studied in terms of advantages and. drawbacks when applying it to target tracking system. ZigBee standard is suitable in target tracking system for its low cost and low energy consumption quality, but lack of real-time transmission guarantee, so modifying ZigBee protocol to enhance its transmission quality to decrease the transmission delay is necessary.Based on this point, a dual-rate beacon communication protocol is proposed, it divides the network into different part to adopt different beacon settings based on the location of the target. It meets the low power consumption while maintaining low transmission delay. Moreover, the performance of this protocol is studied compared to single rate beacon method by OPNET simulator in terms of energy consumption and end-to-end transmission delay. The impact of different parameters on the system performance is also illustrated.A communication platform is built based on CC2430 to implement the dual-rate beacon communication protocol based on ZigBee beacon mechanism. The experiment compares the performance of the dual-rate beacon communication protocol with the original ZigBee, the results show that our dual-rate beacon communication achieves low end-to-end delay while still maintains low energy consumption. It validates the feasibility to apply ZigBee to target tracking system.