Spectrum Sharing Spectrum Sensing Technology Research Of Wireless Communication

As an emerging spectrum sharing technology, Cognitive Radio makes a greatsignificance for improving the utilization of spectrum and solving the problem of theshortage of spectrum resources. Though detecting for idle spectrum in environment,Cognitive Radio share the spectrum resources with authorized users and do not affectthem for dynamic opportunistic accessing to spectrum for communication.Spectrum sensing detects the space environment to find idle spectrum and provideto the cognitive users. As one of the key technologies of Cognitive Radio, spectrumsensing is the premise and foundation of formation a Cognitive Radio system andensures the system work stably. This thesis mainly studied the spectrum sensing inCognitive Radio and implemented in hardware platform based on the sensing algorithm,it provides the idle spectrum for business transmission at the built Cognitive Radionetwork.This paper focuses on the implementation of spectrum sensing in dynamicspectrum sharing broadband wireless system network. Firstly, it studied the sensingalgorithms with single node. After contrasting the advantages and disadvantages of thevarious algorithms, the system selects the Covariance Absolute Value (CAV) forimplementation, and it also can support for cooperative sensing with multiple nodes.Then, based on software radio platform and system requirements, it designed the overallsystem solutions of spectrum sensing, completed interfaces debugging and protocoldesigning between DSP and FPGA, DSP and DSP, DSP and MAC for data processingand results reporting. Finally, by analyzing the system requirements, it designed thesoftware threads of sensing scheduling based on DSP/BIOS, each thread deal with thereceived data and in response to the commands from upper layer with basic hardware.Because the system works at TV channel from694MHz to806MHz, and the CAVdetection cannot distinguish the types of detected signals, this paper proposed a simpleand rapid identification of digital television signal and analog TV signal.In chapter4, sensitivity test of spectrum sensing is done in the system after theimplementation of CAV algorithm. The test shows that DTMB signal of-106dBm and PAL signal of-115.5dBm can reach the90%probability of detection under the detectiontime of less than1ms. The test of recognition of signal types shows that the proposedmethod can quickly and accurately distinguish the types of detected signals. At last, aseries of tests including the sensing function, services transmission, authorized usersavoiding, spectrum switching and cell switching took at the field environment. The testsshow that the spectrum sensing can worked and ensured for the normal operation of thesystem accurately and stably.