Design Of Platform Based On Spectrum Sensing Function Of Cognitive Radio

As a solution to the scarcity of the spectrum resources, cognitive radio can let the users communicate with each other without affecting the authorized users of the specialized spectrum through real-time detection of the wireless environment, which can effectively improve the utilization of spectrum resources.This paper first describes the theory of cognitive radio, introducing the background, concept, key technologies and developments of the cognitive radio, especially the spectrum sensing function. Then it discusses the hardware platform related technologies based on spectrum sensing function of the cognitive radio:the signal sampling theory, multirate signal processing, digital down conversion theory and the PCI bus standard.Based on these theories, the overall design of the platform based on spectrum sensing function of the cognitive radio is discussed in the paper, focusing on the design of the digital down-converter, including the design of the band-pass sampling and several digital filters. Then the band-pass sampling and digital down converter is simulated in the Matlab software.The paper then implements the overall function of all the key modules of the platform based on spectrum sensing function of the cognitive radio, including the RF analog front end, IF amplifier, AD sampling circuit, the digital down converter, and implementation of the PCI interfaces. The hardware platform is constructed with multiple conversion superheterodyne receiver architecture, receiving and down-converting the signals to the analog IF signal by the RF analog front end and amplifying the signals by IF amplifier circuit, sampling the bandpass signals with the ADC converter, using the digital down converter implemented by FPGA for decimation and filtering and then transfering the data via PCI interface to the Industrial Personal Computer.The paper shows a new design of the platform based on spectrum sensing function of the cognitive radio after the study of the spectrum sensing function of cognitive radio. The design is easy to implement and configure, which fully reflects spectrum sensing function of the cognitive radio.