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

2. Month Year
doc.: IEEE 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

3. 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

4. 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

5. 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

6. 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

7. 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

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

9. 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
Adrian Stephens, Intel Corporation

10. 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