Researches On Cognitive Radio Channel Capacity And Spectrum Sensing Techniques

With the development of wireless communication technology, the license-based approach makes the efficiency of the spectrum usage lower and lower. Cognitive radio is viewed as a brand new approach for improving the utilization of the spectrum.The cognitive radio, built on a software-defined radio, is defined as an intelligent wireless communication system that is aware of its environment and uses the methodology of understanding-by-building on learn from the environment and adapt to statistical variations in the input stimuli, with two primary objectives in mind:highly reliable communication wherever and whenever.In recent years, researches of cognitive radio are mainly focused on 3 directions. fundamentals of cognitive radio; spectrum sensing techniques in cognitive radio; optimization for cognitive network. This paper covered the first two directions.In this paper, we introduced the fundamental problems which affected current researches of cognitive radio such as the research on capacity of cognitive channel with multi-users information theory and the Gel'fand-Pinsker problem. Because of the complexity, it is still an open problem of the research of cognitive channel capacity. The author tried to combine the cognitive channel modeling and the Gel'fand-Pinsker problem to build a novel cognitive channel model and analyzed the achievable rates and achievable rate region of the channel model.Spectrum sensing is viewed as an enabling technique for cognitive radio. In this paper, we analyzed three single-node based spectrum sensing schemes. The receiver characteristic curves and complexity of algorithms were also be analyzed in details. Considered on the complexity of algorithm and the integration of circuits, energy detection would be the best scheme. We analyzed the performance and Receive Operating Characteristic of energy detection over the Nakagami channel model.At the end of this paper, we summarized the results of this paper and pointed out the unresolved issues and the prospects for post-study.