1. doc.: IEEE 802.22-06/0125r0 Submission July 2006 Slide 1 Huawei Interference Detection for Sensing IEEE P802.22 Wireless RANs Date: 2006-07-14 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 802.22-06/0125r0 Submission July 2006 Slide 2 Huawei TWO INTERFERENCE DETECTIONS Orthogonal Interference Detection 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 802.22-06/0125r0 Submission July 2006 Slide 3 Huawei INTRODUCTION otherwise: If interference exists in the frequency domain of the received signals:

4. doc.: IEEE 802.22-06/0125r0 Submission July 2006 Slide 4 Huawei (1) Orthogonal Interference Detection Assume (Q k,i, Q k,i+1 ) is orthogonal to transmitted data (X k,i, X k,i+1 ) A group of received data (Y k,i, Y k,i+1 ) are correlated with orthogonal signal. if interference exists: else: Determine whether interference exists using energy detection: if, interference exists else, interference does not exist. Assume in coherence time and coherence bandwidth, H k,i is constant.

5. doc.: IEEE 802.22-06/0125r0 Submission July 2006 Slide 5 Huawei Orthogonal Interference Detection Technology Use multi groups of received data to increase reliability of the detection Using data of N different time slots to form N-1 group of signal vectors When, interference exists Using data of N different sub-carriers to form N-1 group of signal vectors When, interference exists

6. doc.: IEEE 802.22-06/0125r0 Submission July 2006 Slide 6 Huawei Orthogonal Interference Detection Using Pilot The location of a pilot is known When X k,i at location of pilot is always “1”,the formula is When X k,i at location of pilot is alternatingly “1” and “-1”,the formula is

7. doc.: IEEE 802.22-06/0125r0 Submission July 2006 Slide 7 Huawei Orthogonal Interference Detection Using Traffic Data Traffic data is richer than pilot for interference detection Received symbols Y k,i are buffered Coding and modulation to get X k,i If correct in decoding,then detect interference based on the algorithm mentioned in the previous slide If errors in decoding,then calculate PER (Packet Error Ratio) : If PER>threshold, BS will schedule quiet periods Interference Detection in receiver

8. doc.: IEEE 802.22-06/0125r0 Submission July 2006 Slide 8 Huawei Simulation 1 Detection probabilities under INR=30dB of the algorithm. The upper figure illustrates the detection with one group of symbols while the bottom one illustrates the detection with average of 8 groups of symbols.

9. doc.: IEEE 802.22-06/0125r0 Submission July 2006 Slide 9 Huawei Simulation 2 Detection probabilities under INR=20dB of the algorithm. The upper figure illustrates the detection with one group of symbols while the bottom one illustrates the detection with average of 8 groups of symbols.

10. doc.: IEEE 802.22-06/0125r0 Submission July 2006 Slide 10 Huawei Simulation 3 Detection probabilities under INR=0dB of the algorithm. The upper figure illustrates the detection with one group of symbols while the bottom one illustrates the detection with average of 8 groups of symbols.

11. doc.: IEEE 802.22-06/0125r0 Submission July 2006 Slide 11 Huawei Conclusions of Orthogonal Interference Detection Interference Detection can be done without channel estimation Interference Detection can be done without Service Interruption Multiple groups of received data can be used to increase detection reliability Joint with Decoding and Demodulation

12. doc.: IEEE 802.22-06/0125r0 Submission July 2006 Slide 12 Huawei (2) Interference Detection Using Preambles Assume the system bandwidth is 6MHz PN can be training sequences of frame preambles for downlink frame PN can be training sequences of burst preambles for uplink frame

13. doc.: IEEE 802.22-06/0125r0 Submission July 2006 Slide 13 Huawei Correlation of PN i and PN

14. doc.: IEEE 802.22-06/0125r0 Submission July 2006 Slide 14 Huawei Technology of Interference Detection Using Preambles The transmitted signal (PNm) has correlation with the received signal Energy of the received signal Calculate sum of interference and noise power for each fractional bandwidth, and compare the power with pre-determined threshold. If interference and noise power is larger than the threshold, there is interference on this part of bandwidth. Then get sum of power of interference and noise based on the second equation

15. doc.: IEEE 802.22-06/0125r0 Submission July 2006 Slide 15 Huawei Simulation 1 Performance of interference detection using frame preambles, INR = 0dB

16. doc.: IEEE 802.22-06/0125r0 Submission July 2006 Slide 16 Huawei Simulation 2 Performance of interference detection using frame preambles, INR = -10dB

17. doc.: IEEE 802.22-06/0125r0 Submission July 2006 Slide 17 Huawei Simulation 3 Detection probability VS INR of interference detection using frame preambles for threshold =0.25

18. doc.: IEEE 802.22-06/0125r0 Submission July 2006 Slide 18 Huawei Conclusions of Interference Detection with Preambles Interference Detection can be done without channel estimation Interference Detection can be done without Service Interruption Do not need to schedule QPs, without increasing overhead It can be applied for Fractional bandwidth detection