1. doc.: IEEE 802.22-07/0361-00-0000 Submission July 2007 Hou-Shin Chen and Wen Gao, Thomson Inc.Slide 1 Improved Cyclostationarity based sensing algorithms IEEE P802.22 Wireless RANs Date: 2007-07-17 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 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 802.22-07/0361-00-0000 Submission July 2007 Hou-Shin Chen and Wen Gao, Thomson Inc.Slide 2 Spectrum of the ATSC DTV Signal DTV data are VSB modulated. Before VSB modulation, a constant of 1.25 is added to the 8-level pulse amplitude modulated signal (8-PAM). Therefore, there is a strong pilot tone on the power spectrum density (PSD) of the ATSC DTV signal.

3. doc.: IEEE 802.22-07/0361-00-0000 Submission July 2007 Hou-Shin Chen and Wen Gao, Thomson Inc.Slide 3 Signal Model The received signal contains the signal where w(t) is the additive white Gaussian noise (AWGN) P and are the power and the initial phase of the sinusoidal function respectively The function h(t) is the channel impulse response The parameter is the amount of frequency offset in the unit of Hz

4. doc.: IEEE 802.22-07/0361-00-0000 Submission July 2007 Hou-Shin Chen and Wen Gao, Thomson Inc.Slide 4 Cyclic Spectrum of the Pilot Signal The cyclic spectrum of the received signal must contain the cyclic spectrum of x(t) which is given by

5. doc.: IEEE 802.22-07/0361-00-0000 Submission July 2007 Hou-Shin Chen and Wen Gao, Thomson Inc.Slide 5 Cyclic Spectrum of the Pilot Signal

6. doc.: IEEE 802.22-07/0361-00-0000 Submission July 2007 Hou-Shin Chen and Wen Gao, Thomson Inc.Slide 6 Spectrum Sensing Algorithm 1.Use a proper narrow band-pass filter to filter received signal and obtain a small frequency bands which contains the pilot tone

7. doc.: IEEE 802.22-07/0361-00-0000 Submission July 2007 Hou-Shin Chen and Wen Gao, Thomson Inc.Slide 7 Spectrum Sensing Algorithm 2.Down-converted to lower central frequency 3.Decimate the signal by a proper factor to reduce data rate Note that we will do Step 2 and 3 for multiple times in order to perform cyclic spectrum estimation

8. doc.: IEEE 802.22-07/0361-00-0000 Submission July 2007 Hou-Shin Chen and Wen Gao, Thomson Inc.Slide 8 Spectrum Sensing Algorithm The cyclic spectrum is computed by where and z l D [n] which has central frequency f IF +lf Δ is down- converted and D-decimated samples of the narrow band- pass signal around the pilot. N is the size of FFT. The decision statistic is

9. doc.: IEEE 802.22-07/0361-00-0000 Submission July 2007 Hou-Shin Chen and Wen Gao, Thomson Inc.Slide 9 Simulation Parameters The band-pass filter used to filter the pilot tone has a bandwidth of 40 KHz The band-pass signal is down-converted to f IF equaling to 17 KHz The decimation factor is 200 and the decimation filter is a ±50 KHz low-pass filter The size of FFT is N = 2048 The parameter L is 2 and f Δ is set to be half of the carrier spacing divided by 2L+1. The false alarm rate is set to be 0.1

10. doc.: IEEE 802.22-07/0361-00-0000 Submission July 2007 Hou-Shin Chen and Wen Gao, Thomson Inc.Slide 10 Simulation Results Simulations are run over 10 reference ATSC DTV ensembles and their corresponding symbols are listed below : A : WAS_3_27_06022000_REF B : WAS_311_36_06052000_REF C : WAS_06_34_06092000_REF D : WAS_311_48_06052000_REF E : WAS_51_35_05242000_REF F : WAS_68_36_05232000_REF G : WAS_86_48_07122000_REF H : WAS_311_35_06052000_REF I : WAS_47_48_06132000_opt J : WAS_32_48_06012000_OPT K : WAS_49_34_06142000_opt L : WAS_49_39_06142000_opt

11. doc.: IEEE 802.22-07/0361-00-0000 Submission July 2007 Hou-Shin Chen and Wen Gao, Thomson Inc.Slide 11 Simulation Results