Technical comparison of the value of proposed MAC features Month Year doc.: IEEE 802.11-yy/xxxxr0 January 2005 Technical comparison of the value of proposed MAC features Date: 2005-01-11 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>. Adrian Stephens, Intel Corporation John Doe, Some Company

Month Year doc.: IEEE 802.11-yy/xxxxr0 January 2005 Abstract This submission provides a technical comparison of the philosophies underlying the TGnSync and WWiSE MAC proposals and a complexity/benefit analysis of the TGnSync MAC Adrian Stephens, Intel Corporation John Doe, Some Company

Expectations of the TGn MAC January 2005 Expectations of the TGn MAC Performance gained by the PHY should not be wasted in the MAC Should not waste the opportunity to apply techniques that result in performance improvement Should show a balanced view of complexity/benefit tradeoffs Design a scalable and extensible MAC that keeps pace with PHY data rate improvements Another chance to improve the MAC performance may not come along for a number of years Must address the Applications and usage models identified by TGn Performance must exceed that of proprietary pre-standard products Be relevant and competitive after the potentially lengthy standards-development process Interoperable with existing .11 systems Adrian Stephens, Intel Corporation

Design for extensibility January 2005 Design for extensibility TGn is specifying a standard not just for products that appear in 2005 or 2006. Standard should include features that will permit performance improvements as devices and technology mature. Such features include: Aggregation Rx Assisted Link Adaptation MRMRA Reverse Direction Data These features are required to support CE applications emerging in the same time frame we expect the standard to be completed. Adrian Stephens, Intel Corporation

How does TGnSync MAC match against these expectations? January 2005 How does TGnSync MAC match against these expectations? Robust core set of basic features designed to efficiently use the features of TGn class PHY Addtional features provide particular benefit with particular TGn applications Reverse direction data is effective for improved TCP performance MRMRA is highly effective for VoIP calls. Adrian Stephens, Intel Corporation

Benefits of TGnSync MAC January 2005 Benefits of TGnSync MAC Item Benefit Aggregation Very significant (x3) Reverse direction data 8-36% goodput increase MRMRA ~100% increase in number of VoIP calls Rx assisted link adaptation 30-50% goodput increase over “open loop” Adrian Stephens, Intel Corporation

Benefit of Reverse Direction Data January 2005 Benefit of Reverse Direction Data Natural extension of TXOP concept Results in more fully utilized TXOPs Reduces channel access contention No stall waiting for BA Immediate Block Ack + Reverse Direction Data Delayed Block Ack + No Ack Policy Adrian Stephens, Intel Corporation

MAC Simulation Results January 2005 MAC Simulation Results Results do not include MRMRA Further improvements from MRMRA Adrian Stephens, Intel Corporation

How does WWiSE match up against the TGn expectations? January 2005 How does WWiSE match up against the TGn expectations? Balanced performance/complexity tradeoffs? Performance gained by the PHY should not be sacrificed by the MAC. Need substantial MAC improvements to keep pace with PHY data rates. WWiSE does not accept moderate complexity in the MAC for significant throughput benefits at the highest PHY modes. Misses the opportunity to efficiently support VoIP New and important class of traffic not originally considered by 802.11 Adrian Stephens, Intel Corporation

January 2005 Summary “As simple as possible” initially may sound appealing. In practice it may mean refusing modest investments in new features that yield significant performance gains. Adrian Stephens, Intel Corporation