A Dual-Resolution Wavelet-Based Energy Detection Spectrum Sensing for UWB-Based Cognitive Radios

Abstract

An ultra-wideband (UWB)-based cognitive radio (CR) is a promising technique to utilize 3.1–10.6 GHz band efficiently for high data-rate short-range wireless connectivity even in the overcrowded spectrum. This paper investigates a low power wavelet-based energy detection spectrum sensor that provides high-order band-pass filter function and spectral cooperative sensing with fast spectrum sensing (SS) time. Low power high-frequency harmonic rejection mixer reduces harmonic mixing issue in ultra-wideband SS. The spectrum sensor tailored to the UWB-based CR is fabricated in a 65-nm CMOS technology. It achieves SS range of 3.1–10.6 GHz with detection bandwidth of 132 MHz while consuming 23.6–45.3 mW. The total SS time by using the dual-resolution cooperative sensing is 0.49ms. A wavelet generator achieves 32 dB of detection dynamic range with the minimum detection sensitivity of −75 dBm. 3.1–5 GHz harmonic rejection mixer suppresses the third harmonic to −32 dBc. Die area is $2.75 ~\textrm {${\mathrm{ mm}}^{2}$}$ with on-die phase-locked loops.