Research Of Spectrum Detection Design In Cognitive Radio

The thesis comes from the National High-tech Research and Development Program (863 Program): the research of cognitive radio technique. With the rapid development of wireless communication, the finite spectral resource becomes more lacking in the fixed assignation mode, in which the utilization percent of spectral resource is low. Cognitive radio is defined as an intelligent wireless communication system that is aware of its surrounding environment and uses the methodology of understanding-by-building to learn from the environment and adapt its internal states by making corresponding changes in certain operating parameters in real time, in order to promote the efficient use of the spectrum and revive the lack of spectral resource.As one part of the 863 Program, the thesis mainly researches the techniques of wireless environment cognition and detection of spectrum holes in cognitive radio. The improved method of the interference temperature estimation holds multitaper method's accuracy and near-optimality, and substitutes the relation between matrix singular value and matrix element for SVD in order to reduce its operations, improve its performance of real time and get the accurate relation between interference temperature and power spectrum. In another task, the dynamic detection method of spectrum holes could auto-adaptively change operating parameters based on strict interference temperature limit initialized by the cognitive radio services. The method could auto-adaptively changes spectral resolution by the changes of interference temperature estimate values, thus is provided with better spectral resolution and complexity performance. At the last part, the detection and analysis of spectrum holes in GSM and WLAN frequency bands is measured in order to validate that many waste spectrum holes exist even in the frequently occupied channels. The measure establishes a stable base for the cognitive radio research.