Research And Implementation Of MAC Layer Of WLAN In IEEE802.11

IEEE802.11 is now the most popular wireless Standard, it has occupied absolute superiority position in the wireless local area network (WLAN) field.In accordance with IEEE802.11g Standard,in the 2.4 GHz band,we can achieve maximum 54 Mbit / s data transmission rate, it has played a great role in promoting the WLAN Development.This study is based on the National Development and Reform Commission demonstration's project : next generation of wireless Internet access terminal.The project's goal is to implement a basic modules of MAC layer which can be debugged together with the PHY layer implemented by another team of Chongqing University. Research on IEEE802.11 protocol has important practical significance for studying wireless LAN technology and the development of its own intellectual property rights wireless networking products.RTOSμC/OS-II was chosen as the software platform.,while for the hardware platform, S3C2410,a high-performance low-power SOC chip based on the ARM920T core ,which is a production of Samsung company ,was chosen.Therefore, this paper gives a simple description and analysis forμC/OS-II, and how to transplantμC/OS-II in the ARM was discussed too.This paper analyses the system of the MAC layer, according to the system diagram, the module functions and H. Gomma principle which is the principle in divding the embedded systems, the system was divided into 6 missions as for both transmission and receptionpart .The 6 missions for transmission are as below: MSDU_from_LLC, PrePare_MPDU, PM_Filter_STA, Tx_Coordiantion, Backoff_Procedure and Data_Pump. While for reception part , the 6 missions are: Channel_state, Validate_MPDU, Filter_MPDU, Defragment, Rx_Coordination and MSDU_to_LLC.According to the system functional module, and the selected embedded RTOSμC/OS-II's task scheduling mechanism, different mission was assigned a different priority, and the software design flow of the module were drawn too.For the entire software system and the overall planning system the implement of the MAC protocol system, the author defines the data or functions which will be use by multiple tasks solely.And in accordance with the operator function of the different functions the author wrote the corresponding. C or. H documents. Finally the procedures of all the missions of the MAC layer and the debugging procedures were finished ,and then transplanted into ARM for debugging.The debugging result was sent back by the serial port ,and was analyzed. According to the results, the paper has implemented the principal functions of IEEE802.11 MAC layer, and it was a good foundation for implementing the project :next generation of wireless Internet access terminal...