October 30, 2008
Shared Spectrum Company (SSC) Submitted Comments and Field Test Results in Support of the FCC TV White Space Proceedings
Category: Press Releases
On October 23, 2008, Shared Spectrum Company (SSC) submitted Comments and Field Test Results to the FCC in support of the FCC’s TV White Space Proceedings. The field test results are described in a paper entitled “Using Joint Detection to Allow Safe Operation of Television Band ‘White Space’ Devices,” a previous version of which was recently presented at the 3rd IEEE International Symposium on New Frontiers in Dynamic Spectrum Access Networks (Chicago, IL, Oct. 14-17, 2007). This paper reports the results of a study and analysis conducted by SSC to determine a range of detection thresholds at which new dynamic spectrum access (DSA) devices can safely operate in unoccupied spectrum allocated to terrestrial television broadcasting and other services without causing harmful interference.
SSC’s paper shows that to prevent harmful interference to DTV stations, to avoid the “hidden node” problem and to minimize false alarms, a simple joint detection approach can work effectively at reasonable detection thresholds that can vary depending on the DSA devices’ output powers. Specifically, when sensors are paired as indoor and outdoor nodes, the combined information increases the probability of successful detection, ensuring that if one sensor is affected by shadowing or local propagation loss the other sensor is able to provide a more accurate picture. Based on SSC’s analysis of data collected by the synchronized nodes at several locations in Northern Virginia from 13 DTV stations, the paper makes the following conclusions:
- The Listen-Before-Talk, threshold-based approach is an effective dynamic spectrum access technique in the TV white spaces when joint detection is used.
- When joint detection is used, a DSA system using a 10 W transmitter and sensing the DTV pilot threshold at -130 dBm (-118.5 dBm DTV signal power level) results in no or minimal harm and potentially acceptable false alarm rates, but an additional 10 km keep-out distance around the DTV station’s contour is suggested.
- When joint detection is used, a DSA system using a 100 mW transmitter and sensing the DTV pilot threshold of -120 dBm (-108.5 dBm DTV signal power level) would result in no harm and potentially acceptable false alarms rates.
About Shared Spectrum Company
SSC, founded in 2000, is a leading developer of dynamic spectrum access and spectrum measurement technologies. The company has developed innovative cognitive radio technologies for challenging wireless applications in a broad range of the frequency bands. SSC has devised and implemented pioneering solutions for many radio frequency receiver and dynamic spectrum sharing problems. Additional information is available at SSC’s web site, www.sharedspectrum.com.