1. SU-MIMO Type for Group Addressed Frames
March 2011
doc.: IEEE /0313r0
March 2011
SU-MIMO Type for Group Addressed Frames
Date:
Authors:
Jarkko Kneckt, Nokia
Jarkko Kneckt, Nokia

2. Abstract The presentation describes means to detect:
March 2011
doc.: IEEE /0313r0
March 2011
Abstract
The presentation describes means to detect:
The BSSID (TA) of the BSS that transmitted the group addressed frame
The group address (RA) of the transmitted frame
The BSSID and group address detection from the VHT-SIG A enables group addressed receivers to skip the reception of unnecessary group addressed frames and to improve the non-AP STA power efficiency especially in the stand-by mode and in passive scanning.
Jarkko Kneckt, Nokia
Jarkko Kneckt, Nokia

3. Recap, Address Indication in PLCP Header
March 2011
Recap, Address Indication in PLCP Header
802.11ac is introducing new PLCP header format
The PLCP header indicates the recipient(s) and transmitter of the PPDU
Currently the PLCP header indicates:
Individually addressed PPDU to single user (SU)
The AID defines the recipient
Individually addressed aggregated PPDU (A-PPDU) to multiple users (MU)
The Group ID defines the recipients
Group addressed PPDU
The AID set to 0 indicates group address
Jarkko Kneckt, Nokia

4. Challenges of the Address Indication in PLCP Header
March 2011
Challenges of the Address Indication in PLCP Header
Currently PLCP header has partial AID set to 0 for group addressed frames. There is no means to detect:
Transmitter Address (BSSID)
Receiver Address (group address)
The current format forces STAs to receive all group addressed PPDUs
Device cannot filter frames from other BSSIDs
Devices cannot filter frames from unnecessary group addresses that it is receiving
Jarkko Kneckt, Nokia

5. Solution, VHT-SIG A field of the PLCP header
March 2011
Solution, VHT-SIG A field of the PLCP header
Currently VHT-SIG A field is capable to indicate:
63 MU – MIMO groups
1 SU – MIMO transmission type
VHT-SIG A field will be capable to indicate:
62 MU – MIMO groups
2 SU – MIMO transmission types
Bit9 set to 1 for individually addressed PPDU, Partial AID in Nsts field
Bit9 set to 0 for group addressed PPDU , Group Address Indication in Nsts field
Jarkko Kneckt, Nokia

6. Solution, Group Address Indication
March 2011
Solution, Group Address Indication
Introduce GROUP_ADDR_IND:
TXVECTOR GROUP_ADDR_IND[0:3] = BSSID[0:3] XOR BSSID[4:7]
Identification of transmitter address (TA)
TXVECTOR GROUP_ADDR_IND[4:7]= Group Address [0:3]
Identification of receiver address (RA)
TXVECTOR GROUP_ADDR_IND[8] = More Data bit
Are more group addressed frames transmitted by the transmitter
Details of the scheme are described in XXXX-00-00ac-Indication-of-Group-Address.doc
Jarkko Kneckt, Nokia

7. Stand-by Power Consumption
March 2011
Stand-by Power Consumption
In the stand-by the devices receive and transmit very little individually addressed frames
The group addressed data generation may be the only received frames in the stand-by
The device cannot control the amount of group addressed frames:
Other BSSs may distribute a lot of group addressed frames
A STA in BSS may generate and request a lot of group addressed frames transmission
The reception of unnecessary group addressed frames increases the stand-by power consumption
The stand-by power consumption defines the battery life time
Jarkko Kneckt, Nokia

8. March 2011
Filtering of Frames
STAs may stop reception of individually addressed frames to PLCP header
The header contains indication of the transmitter and receiver addresses
The current ac PLCP header has no means to specify the group address or transmitter of the PPDU
The transmitter and group address are present in MAC header forcing to receive the whole MPDU
FCS at the end of MPDU ensures the correctness of the frame
The PLCP header filtering should be used for both the individually and group addressed frames
The same operation simplify the implementation
PLCP Synch + Header
MAC Header
Data Payload
FCS
Jarkko Kneckt, Nokia

9. Comparing the filtering efficiency
March 2011
Comparing the filtering efficiency
TXOP obtaining
TXOP obtaining
TXOP obtaining
Operation flow:
Beacon
Group addressed PPDU
Group addressed PPDU
Time
The SU-MIMO type for group addressed frames enable big increase to sleep durations.
Jarkko Kneckt, Nokia

10. Summary The improved group addressed PPDUs handling enables:
March 2011
Summary
The improved group addressed PPDUs handling enables:
Better addressing of the transmitted PPDUs
More reliability and better understanding of the transmitted traffic
Lower power consumption:
The identifier for the transmitter of the group addressed frame enables filtering group addressed frames to other BSSs
The identifier of group address enables to decide which frames to receive
Especially the stand-by power consumption is reduced
Jarkko Kneckt, Nokia

11. March 2011
Pre-motion
Do you accept to include the normative text as described in ac-SU-MIMO-type-for-group-addressed-frames-text.doc to the spec framework document? Y N A
Jarkko Kneckt, Nokia