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May 2013. Short Management and Short A-MSDU Frame. Authors:. Date: 2013-05-12. May 2013. Short Data/Management Frame in [1]. Some fields in frame header are removed from short MAC data frame. Some fields in frame header are shortened in short MAC data frame.
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May 2013 Short Management and Short A-MSDU Frame Authors: Date: 2013-05-12 Liwen Chu, ST
May 2013 Short Data/Management Frame in [1] • Some fields in frame header are removed from short MAC data frame. • Some fields in frame header are shortened in short MAC data frame. • Issue: A-MSDU encapsulation of short data frames is missing. • Issue: It is not clear whether management frame can be compressed. 2B 2B 6B 2B 6B variable 4B A3 (Optional Present) Body FCS FC Sequence Control A1 (AID) A2 (BSSID) “From DS”=1 Short frame with AID 2B 6B 2B 2B 6B variable 4B A1(BSSID/RA) A2 (AID) Sequence Control A3 (Optional Present) Body FC “From DS”=0 FCS 2B 6B 6B 2B variable 4B Short frame without AID Sequence Control FC TA (MAC Address) Body FCS RA (MAC Address) FC Liwen Chu, ST
May 2013 Data and Management Frame in 802.11 • Data and Management frame formats are similar. So the short frame format can be used for decreasing management frame overhead also. • 4-bit Type subfields can be used to differentiate the short data frames from the short management frames. 2B 2B 6B 6B 6B 2B variable 4B 4B Management Sequence Control HT Control Address 2 Address 3 Body FCS FC Duration Address 1 2B 2B 6B 6B 6B 2B variable 4B 4B 6B 2B Sequence Control HT Control QoS Control Address 2 Address 3 Body FCS FC Duration Address 1 Address 4 Data Liwen Chu, ST
A-MSDU in 802.11 MSDUs from different SA, DA can be encapsulated in one A-MSDU. A-MSDU can be used for AP forwarding. May 2013 A-MSDU Subframe 1 A-MSDU Subframe 2 A-MSDU Subframe n A-MSDU Structure Octets: 6 6 2 variable 0 to 3 AP DA Padding SA Length MSDU A-MSDU Subframe Structure STA1 STA2 STA3 Addresses in A-MSDU frame of STA1 to AP: RA=BSSID, TA=STA1, A3=BSSID, {SA=STA1, DA=Outside MAC or STAi in the BSS} Addresses in A-MSDU frame of AP to STA1: RA=STA1, TA=BSSID, A3=BSSID, {SA=Outside MAC or STAi in the BSS, DA=STA1} Liwen Chu, ST
Short A-MSDU in 802.11 MSDUs from the same SA, DA are in one short A-MSDU. The Short A-MSDU subframe structure is used only between a pair of STAs that communicate directly. May 2013 A-MSDU Subframe 1 A-MSDU Subframe 2 A-MSDU Subframe n A-MSDU Structure Octets: 2 variable 0 to 3 Padding Length MSDU DMG short A-MSDU Subframe Structure Liwen Chu, ST
11ah Short A-MSDU Consideration 4 different addresses are required in relay operation. Duplicate MAC addresses in the A-MSDU subframe can be removed. The negotiated MAC address can be removed from the A-MSDU PPDU. 11ad short A-MSDU is less useful here because of lower throughput requirement of 11ah applications. May 2013 Source MAC Address (Out_Dev) Destination MAC Address (Out_Dev) AP RA=Relay_STA TA=AP DA=STA1 SA=Out_Dev RA=AP TA=Relay_STA DA=Out_Dev SA=STA1 Relay STA RA=STA1 TA=Relay_STA SA=Out_Dev RA=Relay_STA TA=STA1 DA=Out_Dev Source MAC Address Destination MAC Address STA1 STA2 STA3 Liwen Chu, ST
Dynamic A-MSDU Format One or both of the SA, DA from an A-MSDU subframe which are same as the addresses in frame header or are negotiated between the transmitter and the receiver Presence of DA/SA is indicated with DA/SA Present bits in Subframe Control field Enables dynamic indication of different DA(SA) for each A-MSDU subframe Relays can aggregate multiple MSDUs from/to different SA/DA and indicate it for each MSDU if DA(SA) is different from A3/A4 of MAC Header Short A-MSDU format is used in short frame 14 bits for Length field are sufficient for current Max MSDU length (2304 octets) Can indicate up to 16384 octets of maximum MSDU length May 2013 Liwen Chu, ST
Straw Poll 1 May 2013 • Do you agree to include in 802.11ah SFD the AID and MAC address based short management frame with the management indication in FC TBD? Yes No Abstain Liwen Chu, ST
Straw Poll 2 May 2013 • Do you agree to include in 802.11ah SFD that in an A-MSDU the transmitter may remove one or both of the SA, DA from an A-MSDU subframe which are same as the addresses in frame header or are negotiated between the transmitter and the receiver with A-MSDU format as described in slide 9? Yes No Abstain Liwen Chu, ST
Reference May 2013 [1] 11-11/1137r13 Proposed Specification Framework for TGah. Liwen Chu, ST