Design And Implementation Of ZigBee Protocol And Gateway System Of Water Quality Monitoring System Based Cn WSN Technology

WSN (Wireless Sensor Networks) water quality monitoring online system using WSN technology, intelligent sensor technology and modern control technology, can achieve monitoring hydrology information real-time and efficiently, including PH, water temperature, ORP and other indicators, thus reach the goals of water pollution warning, water pollutant monitoring and governance effectiveness monitoring. Nodes of water quality monitoring system communicate generally using GPRS or3G technology, the cost of the sensor nodes is relatively high, and not suitable for layout large-scale networks. WSN technology based on ZigBee, is a low-power, low complexity, low data rate, low cost, short-range wireless network communication technology. WSN monitoring System does not require the laying of cable, and take the advantages of low cost of system maintenance and flexible node layout, makes intelligent water quality monitoring system using ZigBee technology has become a current research focus.Relying on the Shanghai Institute of Microsystem and the Renesas Mobile cooperation projects "On-line WSN water quality monitoring system development", we propose WSN water quality monitoring system based on ZigBee technology, providing a set of possible project for the rapid deployment of online real-time monitoring of water source hydrological information, the system has been laid in QingCaoSha. ChongMing Island. Shanghai and able to complete the desired effect and purpose. On the basis of a detailed analysis of the requirement of the wireless sensor networks project, we designed and implemented a ZigBee wireless data transfer protocol, and the MAC layer and the network layer of the ZigBee protocol be customized according to such WSN monitoring system for low-complexity applications, remove redundant functions, in order to achieve lower consumption of node chip runcosts; designed and defined a new level of ACP layer (Application Communicate Protocol layer) for the communication standard of commands and data betweenWSN nodes. Meanwhile we make a preliminary research on the ZigBee routing algorithms and channel access methods.The main contents of this paper are listed as follows:(1) Based on the research of IEEE802.15.4/ZigBee protocol standards, we design and implement a software architecture of concise ZigBee protocol stack suitable for low-complexity scenarios. It consists of SubMAC layer, MAC layer, network layer and application layer. First we introduce the communication primitives of ZigBee MAC layer and network layer, primitives is consist of data service primitives and management service primitives. Primitives is the API functions call when layer achieve their functions. The SubMAC layer is the designed level that achieved CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) channel access mechanism of MAC and data transmission function of PHY. The role of SubMAC is agreement with the relationship is more distant between underlying levels and upper levels, to facilitate transplantation on different underlying platform.(2) Based on sensor networks protocol operate system-Chipcon OSAL (Operating System Abstraction Layer) modem, we designed a scheduler program of concise ZigBee protocol stack, and all levels of ZigBee stack correspond to a separate task in the operating system. All layer Tasks communicate with information communication mechanism.(3) For the requirements of project, we propose the framework of the water quality monitoring system,and design layout of WSN-Cellular gateway and sensor nodes. WSN-Cellular gateway is the most critical part of the system, consists of STM32F103xB MCU, GR64GPRS module, CC2530chip, it established a communication interface platform between the upper web server and the underlayer WSN collection network.