1. doc.: IEEE 802.22-06/0127r1 Submission July 2006 Slide 1 Huawei Sensing Scheme for DVB-T IEEE P802.22 Wireless RANs Date: 2006-07-17 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 802.22-06/0127r1 Submission July 2006 Slide 2 Huawei Introduction OFDM modulation is adopted by DVB-T systems. Two modes of DVB-T: 2k mode and 8k mode Two hypotheses for presence and absence of DVB-T signals where r(k) denotes the kth sample of the received signal in the time domain, s(k) denotes DVB-T signals transmitted, and h l denotes coefficient of the lth received path. Several methods to realize detection of DVB-T signals are suggested

3. doc.: IEEE 802.22-06/0127r1 Submission July 2006 Slide 3 Huawei (1) Sliding correlation detection based on cyclic prefixes N denotes the number of sub-carriers of a OFDM symbol, L denotes the length of the cyclic prefixes (CPs). Then the length of a OFDM symbol in time domain is N+L. As shown in the figure above, because the first L samples of the OFDM symbol are the cyclic prefix which is the same as the last L samples. Therefore the samples in prefix have strong correlation with the samples in the end part of the same OFDM symbol.

4. doc.: IEEE 802.22-06/0127r1 Submission July 2006 Slide 4 Huawei Sliding correlation detection based on cyclic prefixes (contd) Sliding correlation of received signals r(k) and r(k+N)* – If a DVB-T signal exists in the received signal, then there is a peak in the result. – Otherwise, only the correlation varies randomly. : delay between received signals and transmitted signals in real environment

5. doc.: IEEE 802.22-06/0127r1 Submission July 2006 Slide 5 Huawei (2) Detection algorithms based on IFFT of pilots Two hypotheses for presence and absence of DVB-T signals (N-Np) data sub-carriers Np pilots N: no. of subcarriers, Np: no. of pilot subcarriers

6. doc.: IEEE 802.22-06/0127r1 Submission July 2006 Slide 6 Huawei Sliding correlation based on time domain pilots Similar to sliding correlation detection based on cyclic prefixes Sliding correlation of received signal r(k) and m(k) If a DVB-T signal exists in the received signal, then there is a peak in the result. Otherwise, only the correlation varies randomly.

7. doc.: IEEE 802.22-06/0127r1 Submission July 2006 Slide 7 Huawei Sliding correlation based on time domain pilot signals in cyclic prefixes Sliding correlation to reduce correlation calculation : L (N+L) multiplications

8. doc.: IEEE 802.22-06/0127r1 Submission July 2006 Slide 8 Huawei (3) Joint detection with multi-antennas Statistic of this detection where ATSC A/74, ATSC Recommended Practice: Receiver Performance Guidelines.

9. doc.: IEEE 802.22-06/0127r1 Submission July 2006 Slide 9 Huawei Simulation A: sliding correlation detection based on cyclic prefixes B: sliding correlation based on time domain pilots C: sliding correlation based on time domain pilot signals in cyclic prefix D: joint detection with multi-antennas E: energy detection in ATSC channel (Pf=0.01)

10. doc.: IEEE 802.22-06/0127r1 Submission July 2006 Slide 10 Huawei Simulation A: sliding correlation detection based on cyclic prefixes B: sliding correlation based on time domain pilots C: sliding correlation based on time domain pilot signals in cyclic prefix D: joint detection with multi-antennas E: energy detection in ATSC channel (Pf=0.05)

11. doc.: IEEE 802.22-06/0127r1 Submission July 2006 Slide 11 Huawei Conclusion Several detection schemes based on features of DVB-T signals are suggested.