Sensing Criteria of TV White Space Devices under Nakagami-Rice Fading

Abstract

Underutilized TV bands that constitute “TV white space (TVWS)” are now open for utilization by other telecommunication services. Spectrum regulator requires the new white space device (WSD) not interfering with the existing digital TV (DTV) service. This paper determines the conditions necessary for harmonious coexistence between the two. The main concern is the sensing WSD (SWSD) that utilizes only spectrum sensing to determine the presence of DTV service. Accuracy of sensing becomes very critical. Here we represent the sensing accuracy by the probability of detection Pr D , whereas the probabilities of miss detection Pr M and false alarm Pr F are indicators of sensing inaccuracy. We investigate Pr D , Pr M , and Pr F of an energy detector, a simple spectrum sensor. Key sensing criteria are the required signal-to-noise power ratio (γ) and the number of energy samples (N). Our objective is to evaluate the effect of Nakagami-Rice fading on γand $N$ for the Integrated Services Digital Broadcasting - Terrestrial (ISDB-T) service. Under a typical fading scenario, the required $N$ is found to be nearly 20 times larger than when fading is absent.