PAPR in LTF’s in with and without rotation of the upper subcarrier Month Year doc.: IEEE 802.11-yy/xxxxr0 June 2006 PAPR in LTF’s in with and without rotation of the upper subcarrier Date: 2006-06-06 Authors: Name Company Address Phone email Assaf Kasher Intel assaf.kasher@intel.com Notice: This document has been prepared to assist IEEE 802.11. 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 802.11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures <http:// ieee802.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 <stuart.kerry@philips.com> 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 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at <patcom@ieee.org>. Assaf Kasher (Intel) John Doe, Some Company

Abstract This presentation addresses letter ballot comment CID 3492 Month Year doc.: IEEE 802.11-yy/xxxxr0 June 2006 Abstract This presentation addresses letter ballot comment CID 3492 3492 Y 192   20.3.3.2.2.4 DT HT-LTF for 40 MHz has the same values as the non-zero tones of the 20 MHz HT-LTF in the control channel for all subcarriers between -58 and -2. The tones in the extension channel are also the same as the non-zero 20 MHz HT-LTF values, except for subcarrier location +5 which is -1 while the 20 MHz HT-LTF is +1 at this location. This means you need to use different HT-LTF patterns for 20 and 40 MHz modes, while you could use only one pattern if all non-zero tones would use the same values. Change subcarrier at location +5 of the 40 MHz HT-LTF from -1 to +1. Assaf Kasher (Intel) John Doe, Some Company

June 2006 Original Text Assaf Kasher (Intel)

June 2006 Design reasoning To save storage space, both sequences are based on the clause 17 LTF sequence. In the 20MHz sequence 4 bits are added to extend the sequence from -26:26 to -28:28 In the 40MHz sequence the legacy sequence is placed at tones 6:58 and -58:-6. 10 bits are added filling the legacy DC tone and the tones -5:-2 and 5:2. The needed storage is 52 bits for the legacy sequence, 4 new bits for the HT 20MHz, and 10 bits for the 40MHz sequence. The filling tones were chosen to minimize the PAPR in the real and imaginary parts Assaf Kasher (Intel)

PAPR results Real Imaginary abs Without Change 7.5 3.7 With Change 8.3 June 2006 PAPR results Real Imaginary abs Without Change 7.5 3.7 With Change 8.3 7.3 4.3 Assaf Kasher (Intel)

Conlclusion The PAPR difference is not large. June 2006 Conlclusion The PAPR difference is not large. The saving in changing the value of the bit are insignificant – I can’t see how it help. My proposal – Reject the comment. Assaf Kasher (Intel)