Research And Implementation Of Cognitive Radio Platform Based On Wireless Lan Driver

With the development of wireless communication technology and the application of wireless service, the demands for wireless spectrum keep rising in the recent years. The spectrum has become a very scarce resource, which would seriously restrict the development of wireless communication. Cognitive radio is considered to be one of the best solutions of this problem. By sensing the external environment, adjusting internal parameters and working conditions according to wireless environment, it can significantly improve the efficiency of wireless spectrum. At present most work has concentrated in the theoretical research of the cognitive radio, few people build cognitive radio platform. This article is to build cognitive radio platform based on Linux wireless LAN driver. The platform has the cognitive ability of PHY and a flexible MAC for cognitive radio.First of all, I describe the basic concept of cognitive radio, the development of cognitive radio platform, and the network structure, frame structure, the processes of IEEE 802.11 MAC layer and PHY layer.Second, I describe the structure of Madwifi driver, the method of implementation of SoftMAC, how to override the MAC layer in the driver and give a brief description of the Linux network protocol stack.Later, I designed a program to get the parameters in the Madwifi driver and set up the experiment platform to get a large number of experimental data. After analyzing these data, I got the parameter of cognitive function of PHY and the method of changing the channel.Finally, I complete a CR-MAC instance for cognitive radio based on this platform and introduce how to use this instance. This platform can complete the basic functions of cognitive radio and meet the requirements of system design. It can provide a platform support for the algorithms of cognitive radio MAC layer.