Controller-based Wireless Sensor Network Mac Layer Of The Fpga Design And Realization

Wireless sensor networks (WSN) is composed of massive sensor nodes which are deployed in monitoring region, forming a self-organized network system through wireless communication, the target of which is to cooperatively sense, collect and process the information in the coverage area, then send to the observer. WSN can be used in environment monitoring, medical treatment and so on.Medium Access Control (MAC) protocol is allocated at very low level of WSN protocols, which is mainly used to control sensor nodes sharing communication medium fairly. MAC protocols have a great influence on the WSN's performance. Different with the traditional wireless networks, improving energy-efficiency and scalability are the major goals of MAC protocol design in WSN.The implementation of IEEE802.15.4 MAC function is designed based on Altera's FPGA in this dissertation. The requirements of MAC protocols and the existing MAC protocols are introduced in this thesis, and the key factors of functions in WSN are also discussed. Through a large amount of NS2 simulations on IEEE 802.15.4, we summarize the impacts of some parameter of CSMA/CA on the performance,in terms of throughput, packet loss rate, transmission delay, and analyze hidden terminal problem,acknowledge mechanismSolutions to the key functional modules of MAC layer are proposed based on FPGA in this dissertation,such as R/Tx module, Frame module,CSMA/CA module,SPI module and CRC module as well.The VerilogHDL language is used to make the design close to the hardware. Afterwards, the core is implemented on our own FPGA platform .Some experiments are designed to testify the system. According to the results, the IP-core meets the requirements for low data rate application of WSN. The performance of scalability is good. The protocol achieved the goal of design, and it is useful for next step research of the IEEE 802.15.4 in WSN.