700MHZ Spectrum Occupancy Measurement And Analysis Based On Dynamic Threshold Level

This thesis comes from the major special project of State Radio Monitoring Center: Research and validation of Cognitive Radio Technology in TD-LTE system. In recent years, a large amount of spectrum resources are needed with the rapid development of wireless communication. However, the current adopted static spectrum management strategy leads to low utilization of spectrum resources. The shortage problem of spectrum resources is more and more serious which restricts the development of the new wireless communication business. To reuse the spectrum resources, Cognitive Radio Technology is considered to be the important technology to solve the shortage problem of spectrum resources, which allows dynamic access to the free spectrum of authorized users. In order to select a scientific and effective spectrum to expand cognitive radio service, firstly we have to conduct a comprehensive spectrum measurement and analysis work in advance to know the spectrum occupancy, which provide the reality basis for the research and service of Cognitive Radio Technology in the future.In this thesis, firstly, the scientific and detailed measurement scheme is developed according to the spectrum occupancy measurement of470-806MHz in Beijing region, which includes selection of location, time arrangement, measurement system construction and parameter setting, etc. A novel method for calculating the dynamic threshold is proposed and the transmission channel is modeled. The obtained threshold through proposed method and the20%root-mean-square method is compared to the theoretical value by the matlab software simulation. Then, the measured mass data is managed based on the obtained dynamic threshold, the spectrum occupancy is analyzed comprehensively in space and time dimensions for intuitively understanding the spectrum utilization and finding the free spectrum to develop the cognitive radio service. Finally, this thesis studies the spectrum sensing and detection techniques and simulates the energy detection algorithm. Energy free or occupied characteristic parameters are calculated based on the spectrum occupancy results, which can be combined with the Cognitive Radio Technology. According to the decision threshold with energy detection algorithm in different false-alarm probability and detection probability, the efficiency and accuracy of energy detection algorithm is improved.