1. doc.: IEEE 802.22-09/0024r0 Submission FCC Report on Sensing of TV Channels IEEE P802.22 Wireless RANs Date: 2009-01-19 January 2009 Victor TawilSlide 1 Authors: Notice: This document has been prepared to assist IEEE 802.22. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEEs name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEEs sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.22. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures http://standards.ieee.org/guides/bylaws/sb-bylaws.pdf including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chairhttp://standards.ieee.org/guides/bylaws/sb-bylaws.pdf Carl R. StevensonCarl R. Stevenson as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.22 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at patcom@iee.org.patcom@iee.org >

2. doc.: IEEE 802.22-09/0024r0 Submission Sensing Concept Can spectrum sensing be used to accurately determine whether a TV channel is occupied or vacant? –If device not sensitive enough, device operates on occupied channel causing interference (Failure A) –If device too sensitive, no channels are available (Failure B) Proof of concept must avoid both types of failures Victor TawilSlide 2 January 2009 See, for example, Fundamental Design Tradeoffs in Cognitive Radio Systems or Fundamental Limits on Detection in Low SNR Under Noise Uncertainty by Department of Electrical Engineering and Computer Science, University of California at Berkley

3. doc.: IEEE 802.22-09/0024r0 Submission Latest FCC Field Testing Program (Sensing) Victor TawilSlide 3 January 2009 Victor Tawil Four Devices Field Tested –Motorola (Geolocation, DTV-only sensing) –Philips (DTV, NTSC and microphone sensing) –Adaptrum (DTV and NTSC sensing, transmit capability) –I2R (DTV, NTSC and microphone sensing)

4. doc.: IEEE 802.22-09/0024r0 Submission Field Test Program TV Sensing Tests Conducted at 9 Locations in Washington/Baltimore Area –5 outdoor locations (2 suburban + 3 rural) –4 indoor locations (FCC + 3 homes) Cable Interference Tests/Observations Conducted at 2 of the 3 homes –Adaptrum transmit capability used Microphone Sensing Tests Conducted at 2 Venues –FEDEX Field (Redskin football game) –Majestic Theater (Phantom Broadway show) –Only Philips and I2R device tested January 2009 Victor TawilSlide 4

5. doc.: IEEE 802.22-09/0024r0 Submission TV Sensing Tests January 2009 Victor TawilSlide 5 Lots of data How to measure accuracy of sensing Define Sensing Error Rate –Number of errors the device makes in determining whether a channel is vacant or occupied/total number of channels over which sensing takes place

6. doc.: IEEE 802.22-09/0024r0 Submission MSTV Observations of FCC Sensing Data January 2009 Victor TawilSlide 6

7. doc.: IEEE 802.22-09/0024r0 Submission January 2009 Victor TawilSlide 7

8. doc.: IEEE 802.22-09/0024r0 Submission Cable TV Test Observations January 2009 Victor TawilSlide 8 Interference from White Space Device transmissions to cable television was tested at two residences Results showed interference to both analog and digital cable service –In one home, analog interferences occurred at distance of about 10 feet and thru interior wall –Transmit power had to be reduced to less than 3 mW to eliminate interference to analog TV and about 5 mW to eliminate interference to digital cable –At second home, transmit power had to be reduced to less than 10 mW to eliminate interference Results fully consistent with earlier FCC testing

9. doc.: IEEE 802.22-09/0024r0 Submission Wireless Microphone January 2009 Victor TawilSlide 9 FedEx Field Microphones on 11 TV channels –21, 23, 27, 31, 33, 34, 43, 44, 45, 47, and 49 Four Test Locations –Field Level, Tailgate Club, 400 Level and Press Box Philips device –Detected one microphone channel at field level and reported all other channels occupied with microphones off – All channels occupied at all other locations I2R device –Detected microphone channels about 50% of the time in most locations, about 20% in worst location (Tailgate club)

10. doc.: IEEE 802.22-09/0024r0 Submission FCC Report, October 2008: Field Test Conclusions Several tests were performed with DTV signals present in adjacent channels. These tests showed that in the presence of moderate-to-strong signals in a first adjacent channel, the detection threshold sensitivity of all of the devices was severely impacted. For some of the devices, the degradation in the detection sensitivity was as much as 60-70 dB. In some cases, the degradation was such that the detection threshold could not be measured. This could impact significantly the ability of the devices to reliably detect TV signals within stations service areas. January 2009 Victor TawilSlide 10

11. doc.: IEEE 802.22-09/0024r0 Submission FCC Report, October 2008: Field Test Adjacent Channel Conclusions January 2009 Victor TawilSlide 11

12. doc.: IEEE 802.22-09/0024r0 Submission FCC Report, October 2008: Field Test Conclusions Wireless microphone sensing tests were performed using the I2R and Philips devices at two field locations. The tests were conducted first with microphones off, and then turned on, in pre-determined channels to determine if the devices could sense the presence of wireless microphones. At both sites and all the test locations, the Philips device reported all the channels on which the microphones were designated to transmit as occupied whether the microphone was transmitting or not. The I2R device indicated several channels as available even when the microphones were on January 2009 Victor TawilSlide 12

13. doc.: IEEE 802.22-09/0024r0 Submission Proposed Recommendation Based on the FCC data in the report, Sensing did not properly detect incumbents, especially with the presence of false alarm. Need improvements Recommend that FCC defers from mandating TV sensing and make it optional until sensing improvements are achieved January 2009 Victor TawilSlide 13

14. doc.: IEEE 802.22-09/0024r0 Submission References Office of Engineering and Technology TV White Space Phase II Test Report. October 15, 2008 January 2009 Victor TawilSlide 14