1. doc.: IEEE 802.22-07/0032r0 Submission January 2007 Slide 1 Soo-Young Chang, Huawei Technologies Interference Detection Using Preambles for Sensing IEEE P802.22 Wireless RANs Date: 2007-01-13 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 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 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 802.22-07/0032r0 Submission January 2007 Slide 2 Soo-Young Chang, Huawei Technologies Interference Detection Using Preambles Incumbent signal detection without service interruption can be achieved. Incumbent signal detection without service interruption can be achieved.

3. doc.: IEEE 802.22-07/0032r0 Submission January 2007 Slide 3 Soo-Young Chang, Huawei Technologies Introduction Otherwise, If interference (or an incumbent user signal) exists in the frequency domain of the received signals, X k,i is the symbol transmitted at time i for the kth subcarrier; H k,i is the channel response at time i for the kth subcarrier; Y k,i is the received symbol at time i for the kth subcarrier; I k,i is the interference signal at time i for the kth subcarrier.

4. doc.: IEEE 802.22-07/0032r0 Submission January 2007 Slide 4 Soo-Young Chang, Huawei Technologies PN Sequences Assume the system bandwidth is 6MHz and a channel band has six subbands each of which has 1 MHz bandwidth. PNs can be training sequences of superframe or frame preambles for downlink frames. PNs can be training sequences of burst preambles for uplink frames.

5. doc.: IEEE 802.22-07/0032r0 Submission January 2007 Slide 5 Soo-Young Chang, Huawei Technologies Correlation of PN i and PN

6. doc.: IEEE 802.22-07/0032r0 Submission January 2007 Slide 6 Soo-Young Chang, Huawei Technologies Principle of Interference Detection Using Preambles The transmitted signal (PNm) has correlation with the received signal, and then get the rough six channel parameters when a channel band has six subbands each of which has 1 MHz bandwidth. Energy of the received signal Then get sum of power of interference and noise based on the second equation

7. doc.: IEEE 802.22-07/0032r0 Submission January 2007 Slide 7 Soo-Young Chang, Huawei Technologies Principle of Interference Detection Using Preambles Part1:Calculate sum of interference and noise power for each fractional band and compare the power with pre-determined threshold. If (interference + noise) power is larger than the threshold, there is interference on this part of bandwidth. So in Simulation Part 1, interference signals are narrow band (200KHz) interferences. Part2:Calculate sum of interference and noise power for the whole TV channel and compare the power with pre-determined threshold. If (interference + noise) power is larger than the threshold, there is interference on this channel. So in Simulation Part 2, interference signals are DTV signal in 6MHz.

8. doc.: IEEE 802.22-07/0032r0 Submission January 2007 Slide 8 Soo-Young Chang, Huawei Technologies Simulation Part 1 (1/3) Performance of interference detection using frame preambles, INR = 5dB

9. doc.: IEEE 802.22-07/0032r0 Submission January 2007 Slide 9 Soo-Young Chang, Huawei Technologies Simulation Part 1 (2/3) Probability of misdetection vs INR for interference detection using frame preambles for threshold = 2.35e-9, and false alarm probability = 10%

10. doc.: IEEE 802.22-07/0032r0 Submission January 2007 Slide 10 Soo-Young Chang, Huawei Technologies Simulation Part 1 (3/3) Probability of misdetection vs INR for interference detection using frame preambles for threshold = 4.4e-9, and false alarm probability = 1%

11. doc.: IEEE 802.22-07/0032r0 Submission January 2007 Slide 11 Soo-Young Chang, Huawei Technologies Simulation Part 2 (1/4) Performance of interference detection using frame preambles, for INR = 5dB and when DTV signal is WAS_3_27_06022000_REF.

12. doc.: IEEE 802.22-07/0032r0 Submission January 2007 Slide 12 Soo-Young Chang, Huawei Technologies Simulation Part 2 (2/4) Probability of misdetection vs INR for interference detection using frame preambles for threshold = 2.5e-9, and false alarm probability = 10%

13. doc.: IEEE 802.22-07/0032r0 Submission January 2007 Slide 13 Soo-Young Chang, Huawei Technologies Simulation Part 2 (3/4) Probability of misdetection vs INR for interference detection using frame preambles for threshold = 4.2e-9, and false alarm probability = 1%

14. doc.: IEEE 802.22-07/0032r0 Submission January 2007 Slide 14 Soo-Young Chang, Huawei Technologies Simulation Part 2 (4/4) More simulation results by different real DTV signal files are in the doc document.

15. doc.: IEEE 802.22-07/0032r0 Submission January 2007 Slide 15 Soo-Young Chang, Huawei Technologies Conclusions Interference detection can be done without channel estimation. Interference detection can be done without service interruption. Do not need to schedule QPs, which avoids increasing overhead. It can also be applied for fractional bandwidth detection.