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doc.: IEEE /0110r3 Submission Data/Management Frame Header Compression 1 MPDU type (Normal or compressed) should be identified by either the PHY or MAC header. –Bit15 in Duration field. –PHY PLCP SIG. –Other methods. BSSID and one AID are used to identify the transmitter and the receiver of the data and management frames. –BSSID field is used to identify whether the frame is in the same BSS. –When “From DS” is 1 and “To DS” is 0, BSSID is the transmitter identifier and AID is the receiver identifier. When “From DS” is 0 and “To DS” is 1, BSSID is the receiver identifier and AID is the transmitter identifier. –When both “From DS” is 1 and “To DS” is 1, compressed MPDU header is not used. –TDLS is not allowed, because two AIDs would be needed. Frame Control Duration/ID /RD/FHC BSSIDAID/DASA Identifier Sequence Control QoS Control HT ControlFrame Body FCS Octets: Variable4 Slide 3 Date: Jan, 2012
Citation preview
doc.: IEEE 802.11-12/0110r3
Submission Liwen Chu Etc.Slide 1
Frame Header CompressionDate: 2012-01-16
Name Affiliations Address Phone email Liwen Chu STMicroelectronics 2525 Augustine Drive,
Santa Clara, CA 95054 +1 919-467-8436 [email protected]
George Vlantis STMicroelectronics 2525 Augustine Drive, Santa Clara, CA 95054
+1 919 451-8109 [email protected]
Authors:
Date: Jan, 2012
doc.: IEEE 802.11-12/0110r3
Submission
MAC Frame Header• The typical frame payload of Smart Grid is tens/hundreds bytes.
– 100 bytes payload frame with 3 MAC addresses has about 30/100=30% MAC header overhead!
– 300 bytes payload frame with 3 MAC addresses has about 30/300=10% MAC header overhead!
• The following parts of the MAC header can be compressed:– Some MAC address fields,– No HT Control field when Reverse Direction (RD) is used,– Do we need 2 bytes Sequence Control in a low rate Smart Grid BSS?
Frame Control
Duration/ID
Address 1 Address 2 Address 3 Sequence Control
Address 4 QoS Control
HT Control Frame Body FCS
Octets: 2 2 6 6 6 2 6 2 4 Variable 4
Frame Header
Slide 2
Date: Jan, 2012
doc.: IEEE 802.11-12/0110r3
Submission
Data/Management Frame Header Compression 1• MPDU type (Normal or compressed) should be identified by either the PHY or MAC
header.– Bit15 in Duration field.– PHY PLCP SIG.– Other methods.
• BSSID and one AID are used to identify the transmitter and the receiver of the data and management frames.
– BSSID field is used to identify whether the frame is in the same BSS.– When “From DS” is 1 and “To DS” is 0, BSSID is the transmitter identifier and AID
is the receiver identifier. When “From DS” is 0 and “To DS” is 1, BSSID is the receiver identifier and AID is the transmitter identifier.
– When both “From DS” is 1 and “To DS” is 1, compressed MPDU header is not used.– TDLS is not allowed, because two AIDs would be needed.
Frame Control
Duration/ID/RD/FHC
BSSID AID/DASA Identifier
Sequence Control
QoS Control
HT Control Frame Body
FCS
Octets: 2 2 6 2 2 2 4 Variable 4
Slide 3
Date: Jan, 2012
doc.: IEEE 802.11-12/0110r3
Submission
Data/Management Frame Header Compression 1• AID/DASA Identifier field are used for indicating AID and DA/SA.
– Bit15~Bit13 is the DA Identifier (when “From DS” is 0 and “To DS” is 1) and SA (when “From DS” is 1 and “To DS” is 0). DASA Identification Request/Response action frames are used to match DASA identifier to DASA MAC address.
– Bit12 ~ Bit0 are used to identify Duration or ID• Frame Type/subtype can be used to differentiate which one it is.
AID DASA Identifier
Bit0 Bit12 Bit13 Bit15
AID/DA RA Identifier
• RD would be relocated from the HT control field into the Duration/ID/RD/FHC field of the compressed header. Bit14 is the “RDG/More PPDU” subfield. Bit12 to Bit0 are the AID indication.
• Frame Header Compression indication would be in the Duration/ID/RD/FHC field of the compressed header. Bit15 is the “FHC” (Frame Header Compression indication) subfield.
• FHC is 1 means that the frame header is compressed frame header.
Duration/ID RDG/More PPDU
FHC
Bit0 Bit13 Bit14 Bit15
Duration/ID/RD/FHC
Slide 4
Date: Jan, 2012
• Single Address frames are not allowed to use compressed frame format.
doc.: IEEE 802.11-12/0110r3
Submission
Data/Management Frame Header Compression 2• MPDU type (Normal or compressed) should be identified by either the
PHY or MAC header.– Bit15 in Duration field.– PHY PLCP SIG.– Other methods.
• Partial AID in PHY SIG is used to identify RA. – If two STAs in the BSS have the same Partial AID, the STAs that have the same
Partial AID are not allowed to use compressed frame by AP (e.g. through management frame).
• MAC address is used to identify TA.• DA/RA identifier identifies DA/SA.
– RDG/More PPDU can be included in the same byte.
• Single Address frames are not allowed to use compressed frame format.
Slide 5
Date: Jan, 2012
doc.: IEEE 802.11-12/0110r3
Submission
Conclusion• Frame header compression can decrease short frame overhead through:
– AID replaces RA/TA MAC address in MAC header,– Partial AID RA MAC address in MAC header,– RD can be used without HTC/VHTC,– SA/DA identifier indentify SA/DA MAC address.
• Further optimization may include decreasing sequence number length etc.
Slide 6
Date: Jan, 2012
doc.: IEEE 802.11-12/0110r3
Submission
Straw Poll 1• Do you support to use Partial AID or AID to replace RA/TA MAC
address?– Y– N– A
Slide 7
Date: Jan, 2012
doc.: IEEE 802.11-12/0110r3
Submission
Straw Poll 2• Do you support to use RD without HTC/VHTC?
– Y– N– A
Slide 8
Date: Jan, 2012
doc.: IEEE 802.11-12/0110r3
Submission
Backup Slides
Slide 9
Date: Jan, 2012
doc.: IEEE 802.11-12/0110r3
Submission
DASA Identification Management• A non-AP STA sends DASA Identification Request frame to the AP to indicate the mapping
between DASA Identifier and DASA MAC Address.
• The AP sends DASA Identification Response frame to acknowledge the mapping between DASA Identifier and DASA MAC Address.
Category Action Value
Dialog Token
DASA Identifier
DASA MAC Address
…… DASA Identifier
DASA MAC Address
Octets: 1 1 1 1 6 1 6
At most 16 DASA Identifier and DASA MAC Address pairs
Identifier Reserved DASA Indication
Bit0 Bit2 Bit3 Bit6 Bit7
DASA Identification Request frame
DASA Identifier field
Category Action Value Dialog Token Status Code
Octets: 1 1 1 2
DASA Identification Response frame
Slide 10
Date: Jan, 2012
