Discussion on possible TxBF options in TGn BF&A ad hoc May 2006 doc.: IEEE 802.11-yy/xxxxr0 September 2006 Discussion on possible TxBF options in TGn BF&A ad hoc Date: 2006-09-06 Authors: 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>. Tomoya Yamaura (Sony) Tomoya Yamaura (Sony)

May 2006 doc.: IEEE 802.11-yy/xxxxr0 September 2006 Abstract In LB#84, we have multiple comments regarding TxBF, and they seems orthogonal each other. This presentation summarises Pros & Cons of possible resolutions Characteristics of each TxBF in the current draft. Tomoya Yamaura (Sony) Tomoya Yamaura (Sony)

Contents Possible Options Summary of characteristics of each TxBF September 2006 Contents Possible Options Pros & Cons for each Summary of characteristics of each TxBF Appendix Tomoya Yamaura (Sony)

Possible Options We have 13 comments to remove or simplify TxBFs September 2006 Possible Options We have 13 comments to remove or simplify TxBFs List is available at the Appendix in this material Each seems orthogonal It is impossible to satisfy all, and we would need compromise Option-1 : Keep as they are Option-2 : Find interoperable solution Just an example below (I’m not recommending this) Mandate one of TxBF flavors for every TxBF capable devices Option-3 : Remove some of TxBF mode(s) Option-4 : Remove TxBF completely I don’t state “faster/slower standardization” in Pros&Cons, because I’m not sure which one would have best support at TGn/WG Tomoya Yamaura (Sony)

Option-1 : Keep as they are September 2006 Option-1 : Keep as they are Pros We can enjoy TxBF gain and meet market requirements now Someone may argue that gain is not enough to compare with required complexity Vendors can optimize TxBF(s) based on their use case and application Cons Too many alternatives in the spec, and hard to keep interoperability between employing different TxBF Longer testing time for certification at WFA Tomoya Yamaura (Sony)

Option-2 : Find interoperable solution September 2006 Option-2 : Find interoperable solution Pros We can enjoy TxBF gain and meet market requirements now Someone may argue that gain is not enough to compare with required complexity Vendors can optimize TxBF(s) based on their use case and application We would expect some level of interoperability among TxBF capable devices employing different TxBF Cons Too many alternatives in the spec Longer testing time for certification at WFA Additional complexity in TxBF capable devices Note : Option-2 and 3 could be adopted simultaneously Tomoya Yamaura (Sony)

Option-3 : Remove some of TxBF mode(s) September 2006 Option-3 : Remove some of TxBF mode(s) Pros We can enjoy TxBF gain and meet some of market requirements now Someone may argue that gain is not enough to compare with required complexity We have smaller set of TxBF alternative(s) and some level of interoperability among TxBF capable devices employing different TxBF may become easier Shorter testing time for certification at WFA Cons Become harder to optimize TxBF(s) based on their use case and application Note : Option-2 and 3 could be adopted simultaneously Tomoya Yamaura (Sony)

Option-4 : Remove TxBF completely September 2006 Option-4 : Remove TxBF completely Pros No interoperability issue, at least within IEEE standard Shorter testing time for certification at WFA Cons We cannot enjoy TxBF gain nor meet market requirements now Spending more years to standardize TxBF at a new TG would make industry growth slower This may stimulate proprietary implementation of TxBF, and it may cause non-interoperability issue Tomoya Yamaura (Sony)

Summary of characteristics of each TxBF September 2006 Summary of characteristics of each TxBF Implicit Explicit Implicit CSI Non-compressed V Compressed V Training overhead Smallest Large Small Complexity at Beamformer Beamformee Both (but not so big at BFer) Generally, easier for # of BFer ant. >= # of BFee ant. # of BFer ant. =< # of BFee ant. Rx only ant. at BFee Work as additional diversity branch Can be used for optimizing steering matrix Steering latency Shorter Longer Calibration Required for BFer Not required Others Easily support single stream devices Tomoya Yamaura (Sony)

May 2006 doc.: IEEE 802.11-yy/xxxxr0 September 2006 Appendix - List of comments related to this issues (quoted from 06/1305r1) Tomoya Yamaura (Sony) Tomoya Yamaura (Sony)

Group-1 : Reducing modes of TxBF May 2006 doc.: IEEE 802.11-yy/xxxxr0 September 2006 Group-1 : Reducing modes of TxBF 261 : remove CSI FB and Uncompressed V FB 503 : remove implicit TxBF 710 : choose one, or remove all 3505 : remove two of the three of explicit TxBF 3872 : choose one TxBF mode 7237 : justify, or remove two of the three of explicit TxBF 7417 : remove Uncompressed V FB 7418 : remove Compressed V FB 8050 : remove two of the three from explicit TxBF 8141 : remove Compressed V FB, and possibly one more explicit FB 8195 : remove Compressed V FB 12035 : Remove TxBF until we could define smaller set of TxBF 12053 : Remove TxBF until we could define smaller set of TxBF Tomoya Yamaura (Sony) Tomoya Yamaura (Sony)