1. doc.: IEEE 802.22-07/0179r0 Submission April 2007 Wu Yu-Chun, Huawei HisiSlide 1 CRC_Length_and_FEC_gain_of_PSDU for the 802.22.1 IEEE P802.22 Wireless RANs Date: 2007-04-11 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 802.22-07/0179r0 Submission April 2007 Wu Yu-Chun, Huawei HisiSlide 2 Abstract We compare the Miss Alarm Ratio of 4bits and 8bits CRC at the 10% and 1% PER point, so that our group can decide how much CRC bits we would use. Also, the FEC gain of the 18bytes original length was provided.

3. doc.: IEEE 802.22-07/0179r0 Submission April 2007 Wu Yu-Chun, Huawei HisiSlide 3 Content  Miss Alarm Ratio with 4bits and 8bits CRC.  FEC gain of the 18bytes original PSDU length.  Suggestions

4. doc.: IEEE 802.22-07/0179r0 Submission April 2007 Wu Yu-Chun, Huawei HisiSlide 4 Miss Alarm Ratio with 4bits and 8bits CRC (1/3) The FEC procedure of PSDU with original length of 18 bytes(144 bits). 144-bit Original PSDU Data 4/8-bit CRC 6-Tail bit ½ Rate (Output 308/316-bit) Convolutional Code Repeat to 384-bit (40ms) Modulation and Tx Figure 1: The FEC Design of PSDU

5. doc.: IEEE 802.22-07/0179r0 Submission April 2007 Wu Yu-Chun, Huawei HisiSlide 5 Miss Alarm Ratio with 4bits and 8bits CRC (2/3) Figure 2: The PER and Miss Alarm Ratio

6. doc.: IEEE 802.22-07/0179r0 Submission April 2007 Wu Yu-Chun, Huawei HisiSlide 6 Miss Alarm Ratio with 4bits and 8bits CRC (3/3)  From the Simulation Results, we can see that: Miss Alarm Ratio10% PER point1% PER point 4bits CRC45*10 -4 4*10 -4 8bits CRC17*10 -4 1*10 -4  Also From the Simulation Results, we can see that, the FEC gain difference between 4bits and 8bits CRC is only about 0.1dB. Table 1: Miss Alarm Ratio of different CRC length

7. doc.: IEEE 802.22-07/0179r0 Submission April 2007 Wu Yu-Chun, Huawei HisiSlide 7 FEC gain of the 18bytes original PSDU length (1/3) 144-bit Original PSDU Data 8-bit CRC 6-Tail bit ½ Rate (Output 316-bit) Convolutional Code Repeat to 384-bit (40ms) Modulation and Tx Figure 1: The procedure of FEC with Original length of 144bits and 384bits after FEC

8. doc.: IEEE 802.22-07/0179r0 Submission April 2007 Wu Yu-Chun, Huawei HisiSlide 8 FEC gain of the 18bytes original PSDU length (2/3) Figure 3: The performance of FEC with Original length of 144bits and 384bits after FEC

9. doc.: IEEE 802.22-07/0179r0 Submission April 2007 Wu Yu-Chun, Huawei HisiSlide 9 FEC gain of the 18bytes original PSDU length (3/3)  From the Simulation Results, we can see that: FEC gain10% PER point1% PER point 384bits after FEC7dB6.7dB Table 2: FEC gain

10. doc.: IEEE 802.22-07/0179r0 Submission April 2007 Wu Yu-Chun, Huawei HisiSlide 10 Suggestions Based on the Simulation results and assumed that we are satisfied with the Miss Alarm Ratio of 8bits CRC. I suggest that: 1) Applying 8bits CRC to both of the three part of PSDU, so that we can decrease the complexity because we only need one CRC-appending device. 2) The FEC of the beacon header is: 16bytes original length (including one byte CRC) => 34bytes after FEC So that the total PSDU length is: 34+50+32=116bytes = 96.6ms (plsease refer[1]), which is a multiple of 1 slot = 4 bytes; If WRAN don’t need to receive the Certificate part, then the length will be 84bytes = 70ms,

11. doc.: IEEE 802.22-07/0179r0 Submission April 2007 Wu Yu-Chun, Huawei HisiSlide 11 Questions? (1/1) Any questions and suggestions on future work are highly appreciated

12. doc.: IEEE 802.22-07/0179r0 Submission April 2007 Wu Yu-Chun, Huawei HisiSlide 12 References 1. 《 22-07-0xxx-00-0001_TG1_Preliminary_Draft_Clause_5 (1) 》, Monique sent to reflector on April 11, 2007