Impacts of adaptive modulation on system level design for IEEE802.22 Cognitive Radio receiver

This paper demonstrates a system level design of a Cognitive Radio (CR) receiver that supports IEEE 802.22 Standard. In this work, we put a special interest on the impact of adaptive modulation on the design of the Radio Frequency (RF) receiver Front-End. Its architecture is based on super-heterodyne receiver supporting Sub-Band Sensing technique. In this study, the IEEE 802.22 radio system characteristics are dispatched throughout the different RF receiver blocks. Besides, theoretical computation and various techniques of the system level design are developed. Simulation results for RF characteristics such as noise figure (NF), linearity (third order intercept point, (IIP3)), gain, and output power are introduced. The obtained specifications for each RF block proved that its linearity and NF requirements are related to its own gain performance. The receiver performs a total gain of 54dB and an IIP3 of -17.8dBm for low gain mode. It achieves 105dB as gain, IIP3 of -23.7dBm and a noise figure of 6.6dB for high gain mode.