Design Of WSN Node Circuit And Analysis Of Multi-business Based Probability Detection For Random Multi-access MAC Protocols

The "Twelth Five-Year Guideline" of China explicitly pointed out that to layout ing comprehensive strategic new industry,developping the new generation information technology.As an important part of the information technology,the Internet of Things has long been the global hot spot,and WSN is the most direct reflection of the application of IOT,so,the research of WSN has great signification.Sensor nodes are the base elements of WSN, it’s not only because they are the carriers of WSN protocols, principles and algorithms but also the foundation cells when WSN realizes information sense, data processing and wireless communication. WSN contains large amount of nodes,how to guarantee the fairness when the nodes share the channel and resource involves the MAC protocols. WSN is related to many application aspects, different application requires different net performance. So, it’s hard to adopt universal MAC protocol in WSN,and the design of MAC protocols also becomes the key point in WSN.The research of this paper is mainly based on WSN hardware nodes and MAC protocols. First, it proposes the purpose and meaning of the article after presenting the definition, structure, characteristics, key technology and application prospect in details. Then in chapter2, after the study of literature, designed the hardware platform of WSN. At the beginning, set up the node according to the modular thought of data collection module, data processing module, wireless communication module, power module. After that, chose the ATmegal28L8bit single-chip microcomputer as the MCU accroding to low energy consumption,low cost,high lwvel of integration and high processing ability,and chose TI-chipcon CC2420as the RF transceiver chio through the comparison and analysis on low power consumption, low rate,and high sensitivity level. Then used the EDA software Protel DXP2004to draw the circuit principle diagram, the interface circuits around the core module and made the PCB according to the circuit principle diagram. Finally, debuged the node and realized the data collection, the RF communication between the nodes and the serial communication between nodes and computers. In chapter3, placed importance on the net fairness and utilization of the channel resource. Then,designed a new WSN MAC protocol according to the combination control thought of multiple business and probability detection. Used mean period analysis method to set up system model and analysis the theory. Put forward the throughput formula and evaluate the performance of the protocol on Matlab. At last, summarized the article and pointed out the direction of improvement and further research.