doc.: IEEE /0340r0 Submission December 2008 Monisha Ghosh, PhilipsSlide 1 Performance of sensing in TV bands IEEE P Wireless RANs Date: Authors: Notice: This document has been prepared to assist IEEE 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 IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s 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 Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures 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 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at >

doc.: IEEE /0340r0 Submission Abstract Review the results of lab and field tests conducted by the FCC on the Philips sensing device to gain a better understanding of actual sensing performance. Propose a meaningful method of combining sensing with databases. December 2008 Monisha Ghosh, PhilipsSlide 2

doc.: IEEE /0340r0 Submission Sensing Device Whip antenna. Consumer TV tuner. Device tested by FCC had sensing algorithms in software. –Since then FPGA implementation has been tested as well. –Complexity, compared to PHY layer is minimal: only 256 point FFT. Hence: complexity is minimal, and should not be an issue. December 2008 Monisha Ghosh, PhilipsSlide 3

doc.: IEEE /0340r0 Submission FCC Report, October 2008: Clean Signal December 2008 Monisha Ghosh, PhilipsSlide 4

doc.: IEEE /0340r0 Submission FCC Report, October 2008: Captured Signals December 2008 Monisha Ghosh, PhilipsSlide 5

doc.: IEEE /0340r0 Submission FCC Report, October 2008: TV Field Testing December 2008 Monisha Ghosh, PhilipsSlide 6 At each test site, all channels were classified as follows: –Condition I: WSD within contour and viewable picture. –Condition II: WSD within contour and no viewable picture. –Condition III: WSD outside the contour and viewable picture. –Condition IV: WSD outside the contour and no viewable picture. FCC compared performance based only on Condition I (Probability of detection, P D ) and Condition IV (Probability of False Alarm, P FA ). However, the other conditions should be considered as well.

doc.: IEEE /0340r0 Submission FCC Report, October 2008: Field Test Performance December 2008 Monisha Ghosh, PhilipsSlide 7 Condition I (within contour & picture) Condition I and II (within contour) Condition I and III (viewable picture) Condition I, II and III (within contour OR picture) Philips Sensor100 %97.63 %100 %97.9 % Philips Sensor, with 10 dB attenuation 100 %91.54 %97.25 %90.85 % Geolocation/ database 100 % %88.55 %

doc.: IEEE /0340r0 Submission FCC Report, October 2008: Field Test Conclusions for DTV sensing December 2008 Monisha Ghosh, PhilipsSlide 8 Sensing provided BETTER overall detection protection than geolocation/database. –100% of sites with viewable pictures were protected by sensing, compared to % with database. –97.9 % of sites within a contour OR with viewable pictures were protected by sensing, compared to % with database. False alarm rate is higher with sensing, as expected, since the sensor tested in the lab to below – 123 dBm. –Not all channels counted under false alarms were really false alarms since the signal strength was high. –False alarms can be reduced by increasing sensing thresholds.

doc.: IEEE /0340r0 Submission FCC Report, October 2008: Wireless Microphone Observations December 2008 Monisha Ghosh, PhilipsSlide 9 Wireless microphone test in FCC headquarters showed sensing of wireless microphones worked on an empty channel, upto 100ft with intervening walls. Appendix E, measurements at FedEx Field: –Almost all channels had high signal levels: no surprise that channels were declared occupied before mics turned on. –Wireless mics were placed on channels with existing TV stations. –Channel 37 shows high signal level, some interference. –WM (non ESPN) like signals exist on some of the channels Appendix F, measurements at Majestic Theater: –Measured signal strength was > -110 dB: no surprise that channels were declared occupied before mics turned on. –The noise floor was raised by 15 dB (from -110 dB to -95 dB) when mics were turned on.

doc.: IEEE /0340r0 Submission FCC Report, October 2008: Wireless Microphone Signal Measurements, FedEx Field December 2008 Monisha Ghosh, PhilipsSlide 10

doc.: IEEE /0340r0 Submission FCC Report, October 2008: Wireless Microphone Signal Measurements, Broadway December 2008 Monisha Ghosh, PhilipsSlide 11

doc.: IEEE /0340r0 Submission Proposal For Combining Sensing And Databases Test results show that it is difficult to pick a single sensing level –too low: increase in false alarms, too high: increase in missed detections Instead: change sensing level based on database contour: –Inside contour: sense at a low level ( -114 dBm, or possibly, even lower). The sole purpose here is to solve the hidden node problem. –Outside contour: sense at a higher level (- 100 dBm?). This would protect DTV receivers that are outside the “protected contour” but are still receiving a strong enough signal for a viewable picture. –The above scheme will protect DTV receivers based on actual viewability rather than a projected coverage contour, will reduce false alarms significantly, and make use of both the database and sensing output in a meaningful fashion. The DTV transition has already reduced coverage of certain stations, and telling viewers that even though they are receiving a picture, they are not going to be protected just because they are outside of a projected contour will not go down very well. December 2008 Monisha Ghosh, PhilipsSlide 12