This paper describes spectrum occupancy measurements performed in Chicago, IL in November 2005 and proposes long-term studies in multiple locations. The Chicago project consisted of deploying a high dynamic range spectrum measurement system, a data collection and processing system and conducting spectrum occupancy measurements in all bands between 30 MHz and 3,000 MHz (see Figure 1). These measurements were taken over a two-day period and are added to an existing body of data compiled in other cities and regions including Washington, D.C., and New York City. While these studies are critical in determining what bands have low utilization, longer-term studies are crucial in developing new spectrum access technologies such as cognitive radio algorithms related to Dynamic Spectrum Sharing (DSS). The observed low spectrum occupancy in a business center like Chicago indicates that a DSS radio system could access a huge amount of "prime" spectrum. The unoccupied, large contiguous spectrum blocks show that DSS radios can use conventional contiguous waveforms and that high temporal agility may not be required to significantly expand the data capacity of an accessible section of spectrum. From both short-term and long-term spectrum occupancy studies, candidate bands for spectrum sharing can be readily identified along with unique signal characteristics within these bands. The most important use of the data will be to support senior U.S. (and non-U.S.) government officials in taking action to enhance the use of the currently under utilized RF spectrum resources and to make the R&D investments and policy changes needed to support the development of dynamic spectrum sharing radios. Figure 1: Antenna Array with Chicago Loop IntroductionAs the popularity of new wireless applications and devices continues to grow, the demand for spectral capacity is becoming insatiable. Over the past few years such applications as data centric smart phones, Bluetooth headsets, keyboards and mice, broadband WiFi internet connections, satellite radios, and GPS navigation systems (to name only a few) have moved from obscure gadgets for the wealthy to standard devices and capabilities used by the masses. Demand for spectral capacity is fundamentally experiencing a "Quadruple Whammy" composed of the dramatic increase in the number of discrete applications, the rapid rise in the deployment of these applications, the growth in the amount of time each application is utilized, and the radical growth in the data rates used when these applications are operating. These trends are placing enormous demands on the finite spectral capacity. At the same time, it is observed in this, and related studies, that most of the spectrum, in most of the places, most of the time is completely unused. These observations scream for an enhancement to the current block auction system to fundamentally include the time domain in the allocation and command and control regulatory systems to facilitate new dynamic spectrum sharing (DSS) technologies to be developed and deployed ...

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We describe the design and report on experience fielding an end-to-end framework for declarative spectrum management of frequency agile wireless communication devices. As part of the Defense Advanced Research Projects Agency NeXt Generation communication program, we developed a distributed, policy-driven system that restricts spectrum access based on spectral, temporal and geospatial context. We report on our field framework experimentation, illustrating the capability offered to wireless systems, their command & control management, and individual radios for enforcing spectrum access policies while enabling the radios to fully utilize available spectrum in comparison to traditional, static-assignment spectrum access methods.

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