Implementation Issues of A Wideband Multi-Resolution Spectrum Sensing (MRSS) Technique for Cognitlve Radio (CR) Systems

Spectrum sensing is a key function for a cognitive radio (CR) system. An analog-based multi-resolution spectrum sensing (MRSS) technique was proposed as a flexible, low-power, high-speed spectrum-sensing solution. In this paper, implementation issues of the MRSS technique are investigated, and the corresponding practical specifications are suggested. First, nonlinear effects from a voltage-controlled oscillator (VCO) and multipliers are explored. System simulation results show that harmonic distortion components of VCO and wavelet-pulse power levels should be controlled to alleviate these nonlinear effects. Afterward, I/Q phase- and gain-mismatch effects ore addressed. Specifically, narrow-band signals are more sensitive to these gain and phase mismatches compared to broadband digital modulated signals. Overall, phase mismatch is more sensitive than gain mismatch on MRSS performance, showing a linear degradation of a detected power-level up to a 60-degree phase-mismatch