1. Suggested Resolution on CID #10074
May 2006
doc.: IEEE yy/xxxxr0
October 2006
Suggested Resolution on CID #10074
Date:
Authors:
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Tomoya Yamaura (Sony)
Tomoya Yamaura (Sony)

2. May 2006
doc.: IEEE yy/xxxxr0
October 2006
Abstract
I submitted two comments to improve D1.0 for TxBF at asymmetric antenna configuration.
CID#10073 : for explicit TxBF
(Treated as ‘for your reference’ in this document, and this is
covered in r0)
CID#10074 : for implicit TxBF
I would explain potential problem and proposed solution(s).
Tomoya Yamaura (Sony)
Tomoya Yamaura (Sony)

3. Some definitions Beamformer Beamformee Beamformer Beamformee
October 2006
Some definitions
Beamformer
STA that transmits steered frame
It has N-antennas
Beamformee
STA that receives steered frame
It has M-antennas
N-antennas
M-antennas
steered
Frame
Beamformer
Beamformee
Tomoya Yamaura (Sony)

4. CID #10074 : potential problem
May 2006
doc.: IEEE yy/xxxxr0
October 2006
CID #10074 : potential problem
implicit TxBF
N<M
Beamformee
M=3
Beamformer
N=2
TRQ in HTC
[3x2 channel： <3 streams]
This is 2 streams device but;
have to estimate/buffer
2x3 channel
- have to calculate
steering matrix from
2x3 matrix
(ch estimation)
Sounding
[2x3 channel: <3 streams]
(derive V)
steered
frame
[3x2 channel： <3 streams]
Tomoya Yamaura (Sony)
Tomoya Yamaura (Sony)

5. CID #10074 : proposed solution
May 2006
doc.: IEEE yy/xxxxr0
October 2006
CID #10074 : proposed solution
Add capability field for Beamformer (not only for beamformee)
To allow low cost solution at beamformer
capability exchange prior to beamforming
Beamformee
M=3
Beamformer
N=2
TRQ in HTC
[3x2 channel： <3 streams]
(ch estimation)
Sounding
[2x2 channel: <3 streams]
Dimension of sounding is limited based on announced capability of beamformer
+Smaller overhead
(derive V)
steered
frame
[3x2 channel： <3 streams]
Tomoya Yamaura (Sony)
Tomoya Yamaura (Sony)

6. CID #10074 : proposed solution (cont’d)
May 2006
doc.: IEEE yy/xxxxr0
October 2006
CID #10074 : proposed solution (cont’d)
How to add this capability indicator ?
Just define new capability indicator as current draft has for explicit TxBFs
Pros : much simpler to understand
Cons : requires more bits Or
Reuse capability field for beamformee for explicit TxBF, such as CSI feedback
Pros : no additional bits required
Cons : overloading bits may be misunderstood by the beginners
Even if the node doesn’t support explicit feedback, this field shall be set correctly.
BTW, current draft doesn’t mention how to set these fields if these features are not supported.
There is no problem if the node support explicit also.
Same meaning = maximum training dimension.
If beamformer has capability to estimate streams more than antenna numbers, it would be indicated in this field as well.
This another option would be discussed later, when we would find there would not be enough bits.
Tomoya Yamaura (Sony)
Tomoya Yamaura (Sony)

7. TxBF capability field in D1.05
October 2006
TxBF capability field in D1.05
Implicit TxBF
Receiving
Capable
Receive
Staggered
Sonding
Capable
Transmit
Staggered
Sonding
Capable
Receive
NDP
Capable
Transmit
NDP
Capable
Implicit
TxBF
Capable
Calib.
Explicit
CSI TxBF
Capable
Explicit
Non-comp’d
Steering Mtrx
Capable
Explicit
Comp’d
Steering Mtrx
Capable 1 1 1 1 1 1 2 1 1 1
Explicit
TxBF
CSI
Feedback
Explicit
Non-comp’d
Steering Mtrx
Feedback
Explicit
Comp’d
Steering Mtrx
Feedback
Minimal
Grouping
CSI Number of
Beamformer
Antennas
Support
Non-comp’d
Steering Mtrx
Number of
Beamformer
Antennas
Support
Comp’d
Steering Mtrx
Number of
Beamformer
Antennas
Support
CSI Max
Number
of Rows
Beamformer
Support
Reserved 2 2 2 2 2 2 2 2 5
This is the result of resolution of CID#10073
What is the meaning of this ?
See next slide
Tomoya Yamaura (Sony)

8. CSI Number of Beamformer Antennas Support in D1.05
October 2006
CSI Number of Beamformer Antennas Support in D1.05
CSI Number of Beamformer Antenna Support
Indicates the maximum number of beamformer antennas the beamformee can support when CSI feedback is required
Set 0 for single Tx antenna sounding
Set 1 for 2 Tx antenna sounding
Set 2 for 3 Tx antenna sounding
Set 3 for 4 Tx antenna sounding
Tomoya Yamaura (Sony)

9. CID #10074 : Suggested Resolution-1a
May 2006
doc.: IEEE yy/xxxxr0
October 2006
CID #10074 : Suggested Resolution-1a
Updated
Instruct the TGn editor to allocate two bits from a reserved field of the Transmit Beamforming Capability field in the HT Capability element and insert appropriate references to these bits in the description below.
Replacing two reserve bits with “CSI Estimation Capability ” in the Figure n42 shown in line-10 of page-60 (clause ) of D1.05
Adding a new row to the Table n25
CSI Estimation Capability
Indicates the maximum number of space time streams (columns of the MIMO channel matrix) for which CSI can be simultaneously estimated. When staggered sounding is supported this limit applies independently to both the data portion and to the extension portion of the long training fields.
Set 0 for 1 space time stream in estimation of CSI
Set 1 for 2 space time streams in estimation of CSI
Set 2 for 3 space time streams in estimation of CSI
Set 3 for 4 space time streams in estimation of CSI
(Note to TGn editor)
The terminologies of “beamformer” and “beamformee” may be changed depending on the result of comment resolution for CID #472.
Tomoya Yamaura (Sony)
Tomoya Yamaura (Sony)

10. Note for this suggestion
October 2006
Updated
Note for this suggestion
There is no mention for implicit TxBF.
It should be commonly used for explicit TxBF
Difference from other capability bits for explicit TxBF
This specifies estimation capability and other existing capabilities indicate the max number of rows in feedback.
If this bits are ‘01’, for example, it means 2 STS supported in CSI estimation.
Regular sounding up to 2 HT-LTFs
ZLF sounding up to 2 HT-LTFs
Staggered of 2+2 is supported. (But 1+3 or 3+1 are not)
It does NOT mean the STA indicating this SHALL use all rows. It may choose 2 of them for further processing.
Some “rules” should be added in other clause, related to this. And these would be covered by other submissions.
For example, under ,
Sounding packets sent in response to a TRQ shall not set TXVECTOR.NUM_EXTEN_SS to a value greater than the limit indicated by the CSI estimation capability field of the STA that sent the TRQ. When the sounding packet is a ZLF the number of spatial streams corresponding to TXVECTOR.MCS shall not exceed the limit indicated by the CSI estimation capability field of the STA that sent the TRQ.
Tomoya Yamaura (Sony)

11. CID #10074 : Suggested Resolution-1b
May 2006
doc.: IEEE yy/xxxxr0
October 2006
CID #10074 : Suggested Resolution-1b
Updated
Instruct the TGn editor to allocate two bits from a reserved field of the Transmit Beamforming Capability field in the HT Capability element and insert appropriate references to these bits in the description below.
Replacing two reserve bits with “CSI Estimation Capability in implicit beamforming” in the Figure n42 shown in line-10 of page-60 (clause ) of D1.05
Adding a new row to the Table n25
CSI Estimation Capability in implicit beamforming
Indicates the maximum number of space time streams (columns of the MIMO channel matrix) for which CSI can be simultaneously estimated by beamformer when implicit feedback of sounding frame is returned . When staggered sounding is supported this limit applies independently to both the data portion and to the extension portion of the long training fields.
Set 0 for 1 space time stream in estimation of CSI
Set 1 for 2 space time streams in estimation of CSI
Set 2 for 3 space time streams in estimation of CSI
Set 3 for 4 space time streams in estimation of CSI
(Note to TGn editor)
The terminologies of “beamformer” and “beamformee” may be changed depending on the result of comment resolution for CID #472.
Tomoya Yamaura (Sony)
Tomoya Yamaura (Sony)

12. CID #10074 : Suggested Resolution-2
May 2006
doc.: IEEE yy/xxxxr0
October 2006
CID #10074 : Suggested Resolution-2
Instruct the TGn editor to change definition of “CSI number of beamformer antennae” field in the Transmit Beamforming Capability field in the HT Capability element in the description below.
Replacing the field name of “CSI number of beamformer antennas” (now B19, 20) in the figure shown in line-4 of page-47 (clause ) of D1.0 with “CSI number of beamformer antennas / Number of beamformee antennas in implicit feedback”
Changing row of Figure n19 (shown at the bottom of page-49) as follows.
This option would be discussed later, when we would find there would not be enough bits.
Number of beamformer antennas support in implicit feedback / Number of beamformee antennas in implicit feedback
When “Explicit BF CSI feedback” doesn’t indicate “incapable”, this field means;
The maximum number of beamformer antennas the beamformee can support when CSI feedback is required.
When “Implicit TxBF capable” doesn’t indicate “incapable”, this field means;
The maximum number of beamformee antennas the beamformer can support when implicit feedback of sounding frame is returned.
Set 00 for single Tx antenna sounding
Set 01 for 2 Tx antenna sounding
Set 10 for 3 Tx antenna sounding
Set 11 for 4 Tx antenna sounding
(Note to editor)
The terminologies of “beamformer” and “beamformee” may be changed depending on the result of comment resolution for CID #472.
Tomoya Yamaura (Sony)
Tomoya Yamaura (Sony)

13. For your reference October 2006 May 2006 doc.: IEEE 802.11-yy/xxxxr0
Tomoya Yamaura (Sony)
Tomoya Yamaura (Sony)

14. CID #10073 : potential problem
May 2006
doc.: IEEE yy/xxxxr0
October 2006
CID #10073 : potential problem
explicit TxBF using CSI feedback
N<M
Beamformee
M=3
Beamformer
N=2
No problem for channel estimation and packing
CSI, because it would be
capable for 3-streams
CSI FB-RQ
with sounding
[3x2 channel： <3 streams]
This is 2 streams device but;
have to receive/buffer 3x2
CSI feedback
have to calculate
steering matrix from
3x2 matrix
(ch estimation)
CSI data
[2x3 channel: <3 streams]
(derive V)
steered
frame
[3x2 channel： < 3 streams]
Tomoya Yamaura (Sony)
Tomoya Yamaura (Sony)

15. CID #10073 : proposed solution
May 2006
doc.: IEEE yy/xxxxr0
October 2006
CID #10073 : proposed solution
Add capability field for Beamformer (not only for beamformee)
To allow low cost solution at beamformer
Beamformee
M=3
Beamformer
N=2
capability exchange prior to beamforming
CSI FB-RQ
with sounding
[3x2 channel： <3 streams]
(ch estimation)
CSI data
[2x3 channel: <3 streams]
Dimension of CSI feedback is limited based on announced capability of beamformer
+Smaller overhead
(derive V)
steered
frame
[3x2 channel： <3 streams]
Tomoya Yamaura (Sony)
Tomoya Yamaura (Sony)

16. CID #10073 : other consideration
May 2006
doc.: IEEE yy/xxxxr0
October 2006
CID #10073 : other consideration
Why only for CSI feedback ?
For steering matrix feedback (compressed or uncompressed), this doesn’t occur.
Because the dimension of steering matrix would become NxN.
How about N>M case in explicit feedback ?
Current draft has capability indicators of beamformee.
If beamformer would honor capabilities at beamformee, there would be no problem.
Tomoya Yamaura (Sony)
Tomoya Yamaura (Sony)

17. CID #10073 : Suggested Resolution
May 2006
doc.: IEEE yy/xxxxr0
October 2006
CID #10073 : Suggested Resolution
Instruct the TGn editor to allocate two bits from a reserved field of the Transmit Beamforming Capability field in the HT Capability element and insert appropriate references to these bits in the description below.
Replacing two reserve bits with “CSI row number from beamformee” in the figure shown in line-4 of page-47 (clause ) of D1.0
Adding a new row to the Figure n19
CSI row number from beamformee support
00 supporting single row of CSI
01 supporting 2 rows of CSI
10 supporting 3 rows of CSI
11 supporting 4 rows of CSI
The maximum number of rows of CSI explicit feedback from beamformee the beamformer can support when CSI feedback is required
(Note to editor)
The terminologies of “beamformer” and “beamformee” may be changed depending on the result of comment resolution for CID #472.
Tomoya Yamaura (Sony)
Tomoya Yamaura (Sony)