Design And Development Of Wireless Sensor Network Platform

Currently experiments concerning the WSN are mostly carried out by software simulation, yet the inaccuracy of simulation may lead to a misrepresentation of the WSN performance. In the aim of understanding and analyzing WSN protocols and their major performance index, this thesis puts forward a WSN Platform Based on Data Collection, and presents a self-organizing network of multi-node tree structure, as well as a compatible network monitoring system.The thesis analyzes in detail the WSN architecture, including network topology, hardware structure of nodes and the network protocol stack. Several typical MAC protocols, routing protocols and the time synchronization mechanisms-one of the supporting technologies of WSNs-are also discussed in the thesis.In this thesis, a brief introduction of sensor circuit design is firstly presented. Based on the ATmega128L and CC2420 platform, the detailed design of time synchronization protocol, the MAC protocol and the routing protocol are then described. Implementation of the network protocol stack is also presented, components of which include: the receiving function of the physical layer, a time synchronization mechanism based on DMTS, a sleep/listen working mechanism, a CSMA/CA algorithm with ACK and retry, a reliable energy-aware routing algorithm and other required functions. Meanwhile an embedded operating systemμC/OS-Ⅱis transplanted onto the platform to implement the real-time multi-task environment of the protocol stack. In addition, a real-time monitor system of WSN is developed to provide users with network information and monitor network operations.This thesis also includes performance evaluation of the CSMA/CA mechanism, the routing strategy, the preemptive task scheduling mechanism and the data transmission application. The routing strategy and processes of routing establishment, routing failure and routing maintenance are debugged and hence verified. The results show that the WSN platform ensures operation stability and is capable of performing different tasks, by which further research can be achieved.