Research On Spectrum Sensing And Dynamic Access Based On USRP

In recent years,with the rapid development of wireless communication technology,there is increasing demand for wireless services.As a non-renewable resource,radio spectrum became crucially important in the wireless communication technology and business.However,the current spectrum allocation is based on the principle of static allocation,this fixed allocation method makes the available unlicensed bands getting less and less in wireless communication,and it is easy to waste spectrum because of the low utilization rate of authorized bands.The theory of cognitive radio is considered to be an effective method to solve the above problems,which allows cognitive users to communicate and transmit data by using authorized user channels in this premise of without intolerable interference to authorized users.This requires(fiat the cognitive radio system has fast spectrum sensing and flexible dynamic access capability.At present,most of the researches on cognitive radio at home and abroad are based on theory and simulation,lack of testing in the actual wireless environment.Therefore,this paper uses USRP(Universal Software Radio Peripheral)as the hardware platform,GNU Radio(open source software radio)as a software platform,built a cognitive radio communication system.Spectrum sensing and dynamic spectrum access technology can be realized in the actual working environment.The main contents of this paper include the following aspects:First,a wide range of spectrum sensing is achieved on the USRP and GNU Radio platforms.Based on the research of the basic principle of the energy detection algorithm,a wide range energy detection method is implemented on the USRP and GNU Radio platform.The effects of false alarm probabilities on the detection effect are tested.Secondly,two energy detection and optimization algorithms based on a priori information are proposed and implemented based on the traditional energy detection algorithm,and focus on radio and television system and cellular mobile communication system,which are two kinds of cognitive radio system under different authorized user environment.By analyzing the characteristics of these two kinds of cognitive radio systems,respectively,from two aspects of the detection sequence and sub channel division to optimize the energy detection method,using USRP and GNU Radio platform to test and verify the feasibility of the two methods.Thirdly,on the basis of spectrum sensing,established a centralized cognitive wireless network.Using two USRP hardware as a cognitive base station and cognitive users,designed the basic framework of the network.To realize the cognitive base station and cognitive users from the spectrum sense to the free frequency band sent to the idle band dynamic access and other processes.Completed the critical process of testing,and on this basis,the overall performance of the network is tested.