1. TG ax Consideration of Spatial Reuse
April 2013
doc.: IEEE
Jan 2017
TG ax Consideration of Spatial Reuse
Date:
Authors:
Name
Affiliation
Address
Ruimei Li
ZTE
Corporation
ZTE Corporation
No.9 Wu Xing Section,Xi Feng Road Chang’an district
Xi’an, Shaanxi Province P.R.China
Kaiying Lv
Bo Sun
LiRuimei,et,al.(ZTE)
Graham Smith, DSP Group

2. Background OBSS_PD based SR has been defined in [1]
Jan 2017
Background
OBSS_PD based SR has been defined in [1]
When identifying an OBSS PPDU which meets the OBSS_PD based SR conditions, the STA may transmit over the OBSS transmission based on OBSS_PD based SR rules.
SR_Delay entry is introduced to delay the starting time of the OBSS_PD based SR transmission [1]
When a trigger frame is carried in an HE SU/Extend range SU PPDU, the SR field in HE-SIG-A of the PPDU shall be set to the value of SR_Delay to delay the backoff procedure till the end of the received PPDU if OBSS_PD based SR conditions are met.
SR_Restricted entry is introduced to limit the SR transmission within the duration of the OBSS PPDU [1]
When a trigger frame is carried in an HE MU PPDU, the SR field in HE-SIG-A of the PPDU shall be set to the value of SR_Restricted to limit the SR transmission within the duration of the OBSS PPDU if OBSS_PD based SR conditions are met.
SRP based SR might be applied if supported [1]
When detecting a valid OBSS PPDU(s) and retrieving SR parameter(SRP), an 11ax STA may check SRP based SR conditions.
LiRuimei,et,al.(ZTE)

3. Jan 2017
Issue Analysis
When OBSS_PD based SR conditions are not met, does a STA still have a chance to transmit using SRP-based SR operation ?
When the RSSI of the received OBSS PPDU is greater than the STA’s OBSS_PD level, the STA will update its basic NAV at the end of the PPDU
The received OBSS PPDU might carry a trigger frame with SRP info in the common info field so that SRP-based SR conditions could be checked.
However current NAV update rule may stop the SRP-based SR operation
When OBSS_PD based SR conditions are met, does a STA need to consider SRP-based SR conditions if the RXVECTOR of the received PPDU has SR_Delay entry?
The received OBSS PPDU might carry a trigger frame with SRP info in the common info field
The STA may be able to determine the SRP-based SR conditions in order to make sure the SR transmission will not interfere the reception of the OBSS transmissions.
LiRuimei,et,al.(ZTE)

4. April 2013
doc.: IEEE
Jan 2017
Proposal (1/3)
A trigger indication in the HE SIG-A field of an HE PPDU is introduced
A trigger indication is used to indicate that a trigger frame is carried in the detected OBSS HE PPDU
It is the SR_Delay entry in the SR field of HE-SIG-A if an HE PPDU is an HE SU/ER-SU PPDU
It is the SR_Restricted entry in the SR field of HE-SIG-A if an HE PPDU is an HE MU PPDU.
Other SRP entryies in the SR field of HE-SIG-A indicates no trigger frame
第二段：要改成先判断是否满足OBSS_PD based SR 的条件，1）不满足，应该要去读trigger；2）满足，如果是HE SU/ER SU PPDU，则可选是否去读，如果是HE MU PPDU 则肯定不会去读。
另外增加NAV的更新方法：不满足OBSS_PD based SR,但满足SRP_based SR，则不更新NAV，并开始回退
LiRuimei,et,al.(ZTE)
Graham Smith, DSP Group

5. Proposal (2/3) Spatial reuse rules Jan 2017
April 2013
doc.: IEEE
Jan 2017
Proposal (2/3)
Spatial reuse rules
When receiving an HE PPDU with a trigger indication in the HE-SIG-A, if the OBSS_PD based SR conditions are not met, the third party STAs continue to decode the trigger MPDU and obtain the SRP info from the common info field of the trigger MPDU
If the SRP based SR conditions are met, then
The STA may not update its basic NAV at the end of the PPDU, and
The STA may resume its existing back-off procedure, and
The transmit power during SRP-based SR mode is as follows: TXPWRSTA< SRP –RSSI
Where RSSI is the received power level measured from the legacy portion of the OBSS PPDU.
If the SRP based SR conditions are not met, then
the STA shall update the its basic NAV at the end of the PPDU.
第二段：要改成先判断是否满足OBSS_PD based SR 的条件，1）不满足，应该要去读trigger；2）满足，如果是HE SU/ER SU PPDU，则可选是否去读，如果是HE MU PPDU 则肯定不会去读。
另外增加NAV的更新方法：不满足OBSS_PD based SR,但满足SRP_based SR，则不更新NAV，并开始回退
LiRuimei,et,al.(ZTE)
Graham Smith, DSP Group

6. Proposal (3/3) Spatial reuse rules Jan 2017
April 2013
doc.: IEEE
Jan 2017
Proposal (3/3)
Spatial reuse rules
When receiving an HE PPDU with a trigger indication in the HE-SIG-A, if the OBSS_PD based SR conditions are met:
If the PPDU is an HE SU/ER SU PPDU, the third party STAs may choose to continue to decode the trigger MPDU and obtain the SRP info from the common info field of the trigger MPDU. Otherwise , the STA adopts the OBSS_PD based SR rules only.
if the SRP-based SR conditions are met , then the STA may not update its basic NAV at the end of the PPDU and may resume its back-off procedure. The transmit power (TXPWR) should meet both the OBSS_PD based SR rules and the SRP-based SR rules，i.e.,
TXPWR < min( TXPWR OBSS_PD based SR,, TXPWR SRP_based SR)
if the SRP-based SR conditions are not met, then the STA adopts the OBSS_PD based SR rules only.
If the PPDU is an HE MU PPDU，the third party STAs adopt the OBSS_PD based SR rules only.
第二段：要改成先判断是否满足OBSS_PD based SR 的条件，1）不满足，应该要去读trigger；2）满足，如果是HE SU/ER SU PPDU，则可选是否去读，如果是HE MU PPDU 则肯定不会去读。
另外增加NAV的更新方法：不满足OBSS_PD based SR,但满足SRP_based SR，则不更新NAV，并开始回退
LiRuimei,et,al.(ZTE)
Graham Smith, DSP Group

7. Jan 2017
Summary
The spatial reuse with OBSS_PD based SR and SRP based SR is discussed.
The solution is proposed :
Trigger indication in the HE-SIG-A needs to be checked under certain cases.
The conditions of using the SRP info in trigger in conjunction with OBSS_PD based SR are given.
LiRuimei,et,al.(ZTE)

8. Jan 2017
Reference
[1] Draft p802.11ax_D1.0.pdf
LiRuimei,et,al.(ZTE)

9. Jan 2017
backup
LiRuimei,et,al.(ZTE)

10. Proposal text Do you agree to add the following text in 11ax draft?
Jan 2017
Proposal text
Do you agree to add the following text in 11ax draft?
The STA should check the trigger indication when detecting a OBSS HE PPDU to determine whether a trigger frame is carried in the PPDU. If true, the STA should detect the trigger frame and obtain the value of Spatial Reuse fields in Common Info field .The STA use that value to determine whether the SRP-based SR conditions are met.
The trigger indication is the SR_Delay entry in the SR field of HE-SIG-A if the OBSS HE PPDU is HE SU/ER-SU PPDU,or
The trigger indication is the SR_Restricted entry in the SR field of HE-SIG-A if the OBSS HE PPDU is HE MU PPDU.
LiRuimei,et,al.(ZTE)

11. Straw Poll Do you agree to add the following text in 11ax draft?
Jan 2017
Straw Poll
Do you agree to add the following text in 11ax draft?
When receiving a OBSS HE SU/Extend range SU PPDU with the RXVECTOR parameter SPATIAL_REUSE indicating SR_Delay or receiving a OBSS HE MU PPDU with the RXVECTOR parameter SPATIAL_REUSE indicating SR_Restricted, the STA regard that a trigger frame is carried in the PPDU and continue to receive the trigger frame and obtain the values of Spatial Reuse fields in the Common Field of the trigger frame.
Based on the values of Spatial Reuse fields, the STA determines the spatial reuse of the following solicited OBSS HE trigger-based PPDU .
LiRuimei,et,al.(ZTE)