1. doc.: IEEE 802.22-06/0227r0 Submission Nov 2006 Wu Yu-Chun, Huawei HisiSlide 1 Beacon Sync Frame Proposal for the 802.22.1 IEEE P802.22 Wireless RANs Date: 2006-11-02 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 802.22-06/0227r0 Submission Nov 2006 Wu Yu-Chun, Huawei HisiSlide 2 Abstract A New Sync Frame Scheme for the IEEE 802.22.1 standard is proposed. The FEC adopted in this new scheme provides error correction and error detection capability for the Sync Frame. Thus, the robustness can be improved and the probability of successful synchronization can be increased. One of attractive features of this new scheme is that we can gain about 6dB with the new scheme on the AWGN channel with very simple encoding and decoding algorithms. In fact, its encoding is just like adding a CRC, and for decoding, only three XOR operations, one addition operation and one comparison operation are needed for each bit to be decoded.

3. doc.: IEEE 802.22-06/0227r0 Submission Nov 2006 Wu Yu-Chun, Huawei HisiSlide 3 Content  Introduction of the New Sync Frame Scheme  Encoding  Decoding  Simulation Results  Conclusions

4. doc.: IEEE 802.22-06/0227r0 Submission Nov 2006 Wu Yu-Chun, Huawei HisiSlide 4 Introduction of the New Sync Frame Scheme Comparing to the Original Sync Frame Scheme, we add a 26-bit Parity part into the Sync Frame, and replace the 9-bit Index with a 4- bit Index. Our goal is to apply an FEC code to provide both Error Correction and Error Detection ability in the Sync Frame, so that the robustness can be improved and the probability of successful synchronization can be increased.

5. doc.: IEEE 802.22-06/0227r0 Submission Nov 2006 Wu Yu-Chun, Huawei HisiSlide 5  The FEC code we select here is a shortened code, which is a (n,k) = (63-18=45, 37-18=19) linear block code.  In the transmitter side, the encoding is just like adding a CRC. The generator polynomial we are using here is  The 15-bit Sync sequence and 4-bit Index are combined together as a message to be encoded and denoted in a polynomial form as Encoding (1/3)

6. doc.: IEEE 802.22-06/0227r0 Submission Nov 2006 Wu Yu-Chun, Huawei HisiSlide 6  Then The data will be transmitted in the order of where is transmitted first. Encoding (2/3)

7. doc.: IEEE 802.22-06/0227r0 Submission Nov 2006 Wu Yu-Chun, Huawei HisiSlide 7 The Encoding procedure can be implemented as following circuit: Encoding (3/3)

8. doc.: IEEE 802.22-06/0227r0 Submission Nov 2006 Wu Yu-Chun, Huawei HisiSlide 8  For decoding, after finding the start point of the Sync Frame by correlating with 15-bit Sync Sequence, we extract 45-bit data of a Sync Frame and extend it to 63 bit by filling with 0 in the first 18 positions  Then, is fed into the decoder. Decoding (1/3)

9. doc.: IEEE 802.22-06/0227r0 Submission Nov 2006 Wu Yu-Chun, Huawei HisiSlide 9 … The decoder can be implemented as following circuit diagram:

10. doc.: IEEE 802.22-06/0227r0 Submission Nov 2006 Wu Yu-Chun, Huawei HisiSlide 10  From above figure, we can see that only three XOR operations, one addition operation, and one comparison operation are needed for each bit to be decoded. So its complexity is increased very slightly and this is highly preferred for the implementation. Decoding (3/3)

11. doc.: IEEE 802.22-06/0227r0 Submission Nov 2006 Wu Yu-Chun, Huawei HisiSlide 11 Simulation Results (1/3)  For simplicity and to emphasize the key point of FEC, we do not include a Differential Encoder, the Direct Sequence Spread Spectrum (DSSS), and pulse shaping in our simulations. The block diagram of the New Sync Frame Scheme (with FEC) simulator is:

12. doc.: IEEE 802.22-06/0227r0 Submission Nov 2006 Wu Yu-Chun, Huawei HisiSlide 12 Simulation Results (2/3)  To compare with Original Sync Frame Scheme (with No FEC): The block diagram of the Original Sync Frame Scheme (with No FEC) simulator is:

13. doc.: IEEE 802.22-06/0227r0 Submission Nov 2006 Wu Yu-Chun, Huawei HisiSlide 13 Simulation Results (3/3)  The simulation results on the AWGN channel are plotted in the following figure. We can see that 6dB was gained with New Sync Frame Scheme over the original Sync Frame Scheme.

14. doc.: IEEE 802.22-06/0227r0 Submission Nov 2006 Wu Yu-Chun, Huawei HisiSlide 14 Conclusions (1/2) From the previous slides, we can see that the new Sync Frame Scheme has following advantages:  The new scheme maintains the merits of the Fixed Sync Sequence. In other words, in the new scheme, we can still find the start point of Sync Frame quickly by searching the Fixed Sync Sequence.  The new scheme provides error correction capability, which greatly improves the Sync performance (about 6dB gain over the Original Sync Frame scheme when FER≤10 -3 ) and robustness.

15. doc.: IEEE 802.22-06/0227r0 Submission Nov 2006 Wu Yu-Chun, Huawei HisiSlide 15 Conclusions (2/2)  The new scheme provides the error detection capability. Once we decode one Sync Frame successfully, we can obtain the start point of Beacon PSDU with high-level confidence.  The FEC used here has a very simple encoding algorithm as well as a very simple decoding algorithm. The encoding procedure is just like adding a CRC. Regarding decoding complexity, only three XOR operations, one addition operation, and one comparison operation are needed for each bit.  The new scheme needs very small buffer to save the information of g(x) and H, because it is needed only to save one row of H rather than whole H.

16. doc.: IEEE 802.22-06/0227r0 Submission Nov 2006 Wu Yu-Chun, Huawei HisiSlide 16 Thank you! Any comments and questions will be highly appreciated!