1. doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 1 FEC on Sync Burst and PSDU for the 802.22.1 IEEE P802.22 Wireless RANs Date: 2007-03-04 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 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 2 Abstract One of the most important and urgent problem that TG1 group must resolve to finish a complete draft that CAN WORK is: In order that WRAN can sense the beacon with high probability and at the same time, with small complexity and as short sensing window as possible, we must apply proper FEC technique on Sync Burst and PSDU. Here firstly we analyze the performance requirements for sensing the beacon; Then we introduce the design and simulation results of both the Sync Burst and PSDU.

3. doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 3 Content  System Performance Requirements.  FEC Design on Sync Burst and Simulation Results.  FEC Design on PSDU and Simulation Results.  Questions

4. doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 4 System Performance Requirements (1/2)  Based on following Constraints:  The Maximum Beacon Power is 250mW  Reasonably assume that the Beacon Tx Antenna is always higher than Wireless Mike’s Rx Antenna Then from 【 3 】, we can see that the worst SNR will be -2dB  Considering also that :  WRAN can decode the Sync Burst 2~3 times within a 10ms Frame  Most of the time, the BS can make its decision based on the sensing results of several CPEs ；  The Sensing requirements of TV signals ；

5. doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 5 System Performance Requirements (2/2)  Then we establish the following performance requirements for beacon sensing :  Under the worst case -2dB, the WRAN should be able to sense the Sync Burst with probability of at least 90% in a 10ms Frame.  Under the worst case -2dB, the WRAN should be able to sense the PSDU with probability of at least 90% by one shot.

6. doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 6 FEC Design on Sync Burst and Simulation Results (1/5) Figure 1: The FEC Design on SyncBurst Sync Frame With Index X Sync Frame With Index X-1 Sync Frame With Index 1 。。。 Sync Sequence (15 bits) Index (7 bits) Parity (8 bits) Sync Frame Structure Reserve d(2 bits)

7. doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 7 FEC Design on Sync Burst and Simulation Results (2/5) The FEC on Sync Burst is a (15,7) Linear Block Code, The reason that we choose this code is: 1) It has very simple Encoding and Decoding algorithms (Please refer to 【 1 】 for detail). 2) It doesn’t increase the Sync Frame Length too much (Only increase 1 byte). 3) It has error correcting capability and can improve the Sync Burst performance greatly(about 2~5dB). 4) It also provides error detection capability on Sync Burst, which is commonly believed to be a MUST for the Sync Burst.

8. doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 8 FEC Design on Sync Burst and Simulation Results (3/5) Simulation Condition: 1) Assume Perfect Symbol Synchronization; 2) 6-bit Quantization of received signal; 3) DQPSK Modulation and 8-chip Spreading; 4) AWGN and WRAN Profile_A channel; 5) Statistic Length: 10,000 Frames

9. doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 9 FEC Design on Sync Burst and Simulation Results (4/5) Figure 2: Sync Burst Performance with or without FEC under AWGN and Profile A channel

10. doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 10 FEC Design on Sync Burst and Simulation Results (5/5) From the simulation Results, we can see that under the typical WRAN environment: WRAN Profile A channel, at the SNR = -2 point: 1) Without FEC, the BLER is 67%. Even the WRAN can have 3 shots of Sync Burst sensing within a 10ms Frame, and under the assumption that any 1 of the 3 shots pass CRC check, we declare a success detection. the success detection probability is only 1-(0.67*0.67*0.67) = 70%; 2) With FEC, the BLER is 11.5%. Even the WRAN have only 1 shot of Sync Burst sensing within a 10ms Frame, it can almost meet the 90% performance requirements. Moreover, The WRAN can have 2 shots of Sync Burst sensing within a 10ms Frame, then the success detection probability will be 1- (0.115*0.115) = 98.68%; For AWGN Channel, at the SNR = -2 point, The result is same, i.e, with FEC, the performance requirement can be met, otherwise, it fails.

11. doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 11 FEC Design on PSDU and Simulation Results (1/5) Here we take the Original PSDU Length as 26 bytes (208 bits) as proposed in 【 4 】 208-bit PSDU Frame 4-bit CRC 6-bit zero ½ Rate (Output 436-bit) Convolutional Code (CC), The CC is same as what used in WRAN with Constraint Length of 6 Repeat to 480-bit (50ms) Modulation and Tx Figure 3: The FEC Design on PSDU

12. doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 12 FEC Design on PSDU and Simulation Results (2/5) 1) The Original 208-bit PSDU was added by 4-bit CRC and 6 Tail zero bit, now the number of total bits are 218 bits; 2) Then it was fed into ½ Convolutional Coder (the same as WRAN Convolutional Coder), the output are 436bits; 3) To ensure that the performance requirement can be met and at the same time, make PSDU not too long, it was repeated to 480bits(50ms); 4) Finally the repeated PSDU data was modulated and transmitted.

13. doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 13 FEC Design on PSDU and Simulation Results (3/5) Simulation Condition: 1) Assume Perfect Symbol Synchronization; 2) 6-bit Quantization of received signal; 3) DQPSK Modulation and 8-chip Spreading; 4) AWGN and WRAN Profile_A channel; 5) Statistic Length: 10,000 Frames

14. doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 14 FEC Design on PSDU and Simulation Results (4/5) Figure: PSDU Performance with or without FEC under AWGN and Profile A channel

15. doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 15 FEC Design on PSDU and Simulation Results (5/5) From the simulation Results, we can see that under the typical WRAN environment: WRAN Profile A channel, at the SNR = -2 point: 1) Without FEC, the BLER is 96.4%, it’s far away from the performance requirement. 2) With FEC, the BLER is 3.3%, it can meet the 90% performance requirement. For AWGN Channel, at the SNR = -2 point, The result is same, i.e, with FEC, the performance requirement can be met, otherwise, it fails.

16. doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 16 Questions? (1/1) Any questions and suggestions on future work are highly appreciated

17. doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 17 References 1. 《 22-07-0053-01-0001_Huawei_FEC_on_Sync_Frame 》 2. 《 22-06-0245-05-0000_WRAN_Sensing_Window 》 3. 《 22-07-0067-01-0001_Beacon_PER_vs_Distance 》 4. 《 22-07-0031-00-0001_TG1-SecurityOverview 》