RF system level design for a Spectrum Sensing Receiver

This paper presents an RF system-level design of a Spectrum Sensing Direct Conversion Receiver for Cognitive Radios. An extension to the recently developed IEEE 802.22 standard from 54MHz to 4GHz is proposed to take advantage of additional underused frequency bands. The proposed architecture is designed to detect IEEE 802.22, IEEE 802.16, and LTE signals as incumbents. The receiver is composed of low noise amplifier (LNA), mixer and variable gain amplifier (VGA) with noise figure, 1dB compression point, second and third order intermodulation point, and gain defined through budget simulation. Results show that severe linearity requirements are imposed on such receiver due to the strong interferers entering in the wideband receiver.