IEEE P802.22 Wireless RANs Date: 2006-01-18 Month Year doc.: IEEE 802.22-yy/xxxxr0 January 2006 LDPC for IEEE 802.22 IEEE P802.22 Wireless RANs Date: 2006-01-18 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. > Yufei Blankenship, Motorola John Doe, Some Company

Month Year doc.: IEEE 802.22-yy/xxxxr0 January 2006 Abstract Many of the initial 802.22 submissions proposed convolutional codes and convolutional turbo codes. While these codes have the endorsement of being accepted into the initial WiMAX profile, LDPC codes demand consideration due to their characteristic high performance for low complexity, as well as commonality with both 802.16e and (likely) 802.11n. This primer will offer motivation for considering LDPC as the baseline code for 802.22. Yufei Blankenship, Motorola John Doe, Some Company

Motivation for further consideration of LDPC as the baseline code January 2006 Motivation for further consideration of LDPC as the baseline code Convolutional turbo codes (CTC) and LDPC are the two advanced coding alternatives that have been submitted in .22 proposals CTC was chosen for WiMAX because early submission of proposal decoder design is well understood performance is good LDPC wasn’t really hashed out until Jan. ‘05, a bit late for WiMAX However, LDPC is widely perceived as the code of the future High performance and low complexity High throughput LDPC is an option in 802.16e Advanced standards are moving towards LDPC (DVB-S2, 802.16e, 802.11n… 802.22?) Yufei Blankenship, Motorola

Codec Reuse Scenario: 802.11n and 802.22 January 2006 Codec Reuse Scenario: 802.11n and 802.22 to/from rooftop antenna 802.22 radio Common baseband elements (e.g., LDPC codec) ethernet 802.11n uses 802.16e-style LDPC, so encoder/decoder are the same to/from indoor antenna 802.11n radio Yufei Blankenship, Motorola

January 2006 Why LDPC? Massive amount of research on LDPC codes by universities and manufacturers Performance benefits, especially for longer block sizes Low-complexity implementation Highly amenable to parallel processing Low hardware cost for given throughput target LDPC offers complexity improvement over turbo codes Flarion estimates an order of magnitude improvement 3 – 4x improvement achievable Yufei Blankenship, Motorola

January 2006 802.16e LDPC The 802.16e LDPC codes have special design features to further simplify hardware implementation Structured block LDPC for low complexity encoding/decoding One small base matrix (message interconnection) for 19 code sizes of a given code rate Blockwise encoding/decoding Block size of 24 to 96 (related to parallel processing factor), depending on code size Low complexity differential style encoding Compact representation of code matrices Simplified structured decoder architecture across all rates Yufei Blankenship, Motorola

January 2006 Take-Aways Lower-complexity, higher throughput, better performance alternative to turbo codes Standards: DVB-S2, 802.16e, 802.11n Yufei Blankenship, Motorola