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

2. May 2006
doc.: IEEE 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)

3. 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)

4. 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)

5. 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)

6. 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)

7. 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)

8. 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)

9. 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)

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

11. Group-1 : Reducing modes of TxBF
May 2006
doc.: IEEE 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)