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An RF measurement system with high time resolution is implemented to determine the statistical characteristics of various channels in the Land Mobile Radio bands. The applicability of simple statistical models to the observed data is investigated, as well as their validity over short and long periods of time. The results show that the statistics of the idle and holding times of communication on these...
This paper summarizes some of the results of measurements and related analysis efforts at the Illinois Institute of Technology (IIT) Spectrum Observatory in Chicago over the past three years. The results are unique in the sense that the spectral occupancy estimates are based on multiple years of observations, whereas previous studies produced occupancy numbers based on short term snapshot measurements,...
We present the results of a preliminary assessment of the potential for applying Dynamic Spectrum Access (DSA) methods to improve radio frequency spectrum utilization in the land mobile radio (LMR) bands in the U.S. This band includes both public safety and commercial user frequency assignments. First, using RF spectrum measurements made in Chicago, occupancy statistics in the widely used 450–470...
In proposed cognitive radio schemes, channel occupancy is often offered as the metric to determine if a channel is free to open a new communication channel. Channel occupancy is the time average of detected transmissions above a certain power level. In many systems the transmission power between the uplink side and down-link side are asymmetric. If a single power threshold is used, then a system may...
This paper describes research on the development of an appropriate support structure for the analysis of the spectral environments to support the successful deployment and utilization of a cognitive radio system in specific high value spatial domains (e.g. urban centers). Specifically the paper discusses the opportunity to use a system of spectrum observatories augmented by wireless sensor networks...
This paper describes the high value of cognitive radio technology and characterizes the opportunity space in four distinct classes. A Chicago-based spectrum occupancy study illustrates the opportunity showing that 82.6% of the spectral capacity is unused. A set of spectral signatures is presented for common devices in the unlicensed frequency band with the view that this technique can be widely deployed...
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