FEC on Sync Frame for the 802.22.1 Jan 2007 doc.: IEEE 802.22-07/0xxxr0 January 2007 FEC on Sync Frame for the 802.22.1 IEEE P802.22 Wireless RANs Date: 2007-01-17 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 Chair Carl 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. > Wu Yu-Chun, Huawei Hisi Wu Yu-Chun, Huawei Hisi

Jan 2007 doc.: IEEE 802.22-07/0xxxr0 January 2007 Abstract An enhanced Beacon Sync Frame scheme for IEEE Std. 802.22.1 is proposed. This new scheme will provide error correction and error detection capability for the Sync Frame. Compared to the previous proposal in [1], the number of parity bits was reduced and PSDU type information was added so that the WRAN can decide whether it should schedule Quiet Period to listen to the PSDU or not in advance. Wu Yu-Chun, Huawei Hisi Wu Yu-Chun, Huawei Hisi

Content Enhanced Sync Frame Scheme Proposed Encoding and Decoding Jan 2007 doc.: IEEE 802.22-07/0xxxr0 January 2007 Content Enhanced Sync Frame Scheme Proposed Encoding and Decoding Simulation Results Conclusions Wu Yu-Chun, Huawei Hisi Wu Yu-Chun, Huawei Hisi

Enhanced Sync Frame Scheme Proposed (1/2) Jan 2007 doc.: IEEE 802.22-07/0xxxr0 January 2007 Enhanced Sync Frame Scheme Proposed (1/2) Sync Frame With Index X X-1 。。。 PSDU Frame Sync Sequence (15 bits) PSDU Type (1 bit) Index (6 bits) Parity (8 bits) Sync Frame Structure Super Frame Structure DTX(2 bits) Figure 1: The Enhanced Beacon Sync Frame structure The Enhanced Beacon Sync Frame has now 32 bits in total, including 15-bit PN Sequence, 15-bit Information (consisting of 1-bit PSDU type information which tell the following PSDU is for WRAN or for beacon-to-beacon communication, 6-bit Index and 8-bit Parity) and 2-bit DTX (Discontinuous Transmission). Wu Yu-Chun, Huawei Hisi Wu Yu-Chun, Huawei Hisi

Enhanced Sync Frame Scheme Proposed (2/2) Jan 2007 doc.: IEEE 802.22-07/0xxxr0 January 2007 Enhanced Sync Frame Scheme Proposed (2/2) Within the Sync Frame, the PSDU type and Index part need to be decoded successfully with high reliability. Otherwise, the receiver can’t decode the PSDU correctly. So we apply FEC (15, 7) to provide Error Correction and Error Detection capability on the PSDU type and Index part. Also, for the alignment reason, the Sync Frame should include integral number of bytes. So we add 2 DTX bits at the end of a Sync Frame to make it 32bits or 4 bytes in total. Wu Yu-Chun, Huawei Hisi Wu Yu-Chun, Huawei Hisi

Encoding and Decoding (1/4) January 2007 Encoding and Decoding (1/4) The FEC code we select here is a code, which is a (n,k) = (15, 7) linear block code. In the transmitter side, the encoding is just like adding a CRC. The generator polynomial we are using here is The 1-bit PSDU Type and 6-bit Index are combined together as a message to be encoded and denoted in a polynomial form as Wu Yu-Chun, Huawei Hisi

Encoding and Decoding (2/4) January 2007 Encoding and Decoding (2/4) Then The data will be transmitted in the order of where is transmitted first. Wu Yu-Chun, Huawei Hisi

Encoding and Decoding (3/4) Figure 2: The Encoding Circuit of FEC January 2007 Encoding and Decoding (3/4) The Encoding procedure can be implemented as in the following diagram: Figure 2: The Encoding Circuit of FEC Wu Yu-Chun, Huawei Hisi

Encoding and Decoding (4/4) Figure 3: The Decoding Circuit of FEC January 2007 Encoding and Decoding (4/4) The decoder can be implemented as in the following circuit diagram: … Figure 3: The Decoding Circuit of FEC Wu Yu-Chun, Huawei Hisi

Simulation Results (1/2) January 2007 Simulation Results (1/2) The simulation results of 7-bit message without FEC and 15-bit with FEC(15,7) on the AWGN channel are plotted in the following figure. Figure 4: Simulation Results of Sync Frame Wu Yu-Chun, Huawei Hisi

Jan 2007 doc.: IEEE 802.22-07/0xxxr0 January 2007 Conclusions (1/2) From the previous slides, we can see that the Enhanced Sync Frame Scheme has following advantages: The Enhanced scheme provides error correction capability, which greatly improves the Sync performance (about 4.5dB in SNR sense and 1.5dB in Eb/N0 sense). The FEC also provides error detection capability. This is very important to ensure that the WRAN does not waste a long Quiet Period to decode the PSDU when it did not get the correct start position of the PSDU. Wu Yu-Chun, Huawei Hisi Wu Yu-Chun, Huawei Hisi

Jan 2007 doc.: IEEE 802.22-07/0xxxr0 January 2007 Conclusions (2/2) 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. Wu Yu-Chun, Huawei Hisi Wu Yu-Chun, Huawei Hisi

Jan 2007 doc.: IEEE 802.22-07/0xxxr0 January 2007 References 《22-06-0226-00-0001_Huawei_Beacon_Sync_Frame_Proposal》. 《22-06-0245-05-0000_WRAN_Sensing_Window》 Wu Yu-Chun, Huawei Hisi Wu Yu-Chun, Huawei Hisi

Any comments and questions will be highly appreciated! Jan 2007 doc.: IEEE 802.22-07/0xxxr0 January 2007 Thank you! Any comments and questions will be highly appreciated! Wu Yu-Chun, Huawei Hisi Wu Yu-Chun, Huawei Hisi