Dynamic spectrum access operational parameters with wireless microphones

This article provides a comprehensive analysis of dynamic spectrum access operational parameters in a typical hidden node scenario with protected wireless microphones in the TV white space. We consider all relevant effects and use an analysis framework that properly combines probabilistic technical factors to provide specific policy recommendations including the exclusion zone distances and the sensing-based DSA threshold detection levels. First, man-made noise measurements were taken in different locations and the amount of interference from man-made noise in potential wireless microphone channels was analyzed. Data collection results show that man-made noise levels can be up to 30 dB above the thermal noise floor. Furthermore, indoor-to-outdoor path loss measurements were conducted to determine the required exclusion distance for DSA-enabled TV band devices to ensure reliable wireless microphone operation in a typical application. The results show that the required exclusion zone can be safely and conservatively set at around 130 m when the results from man-made noise measurements and wireless microphone propagation measurements are used. Additionally, we developed a simulation to determine the required DSA sensing threshold levels for impairment-free wireless microphone operation. An indoor-to-outdoor path loss model was created based on the above path loss measurement results. This statistical path loss model was used to determine the received signal level at TV band devices and the interference level at the wireless microphone receiver. Our results show that the sensing threshold can be set at around -110 dBm (in a 110 kHz channel) for impairment- free wireless microphone operation when man-made noise and representative propagation models are used.