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Duplicate Detection of Short MAC Frame

Duplicate Detection of Short MAC Frame. Authors:. Date: 2013-01-13. Authors:. Authors:. Introduction. Short MAC Frame Format [1] Order of Address fields From AP to STA: 2 byte AID of receiver followed by BSSID (From-AP = 1)

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Duplicate Detection of Short MAC Frame

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  1. Duplicate Detection of Short MAC Frame Authors: Date: 2013-01-13 YonghoSeok, LG Electronics

  2. Authors: YonghoSeok, LG Electronics

  3. Authors: YonghoSeok, LG Electronics

  4. Introduction • Short MAC Frame Format [1] • Order of Address fields • From AP to STA: 2 byte AID of receiver followed by BSSID (From-AP = 1) • From STA to AP: 6 byte BSSID followed by 2 byte AID of STA (From-AP=0) • From STA to STA: 6 byte destination STA MAC address followed by 2 byte source STA AID (From-AP=0) From-DS = 1 From-DS = 0 Yongho Seok, LG Electronics

  5. Introduction • Duplicate Detection [IEEE 802.11-2012] • Transmitter Side • A STA operating as a QoS STA shall maintain one modulo-4096 counter, per <Address 1, TID>, for individually addressed QoS Data frames. • Sequence numbers for these frames are assigned using the counter identified by the Address 1 field and the TID subfield of the QoS Control field of the frame, and that counter is incremented by 1 for each MSDU or A-MSDU corresponding to that <Address 1, TID> tuple. • Receiver Side • The receiving QoS STA shall keep a cache of recently received <Address 2, TID, sequence-number, fragment-number> tuples from QoS Data frames from all STAs from which it has received QoS data frames. • A receiving QoS STA shall reject as a duplicate frame any QoS Data frame in which the Retry bit in the Frame Control field is 1 and that matches an <Address 2, TID, sequence-number, fragment number> tuple of an entry in the cache that contains tuples of that format. Yongho Seok, LG Electronics

  6. Duplicate Detection Issueof Short MAC Frame • Because Address 1 field of the downlink short MAC frame and Address 2 field of the uplink short MAC frame are set to AID, some text changes of the current spec are needed. • There is an inconsistent issue between MAC Address and AID. • Also, because FC field does not have Retry sub-field, the receiver behavior of the duplicate detection should be changed. • See the proposed changes in the next slide. Yongho Seok, LG Electronics

  7. Proposed Spec Change • Duplicate Detection for Short MAC Frame • Transmitter Side • A STA operating as a QoS STA shall maintain one modulo-4096 counter, per <STA MAC Address identified by Address 1, TID>, for individually addressed QoS Data frames. • Sequence numbers for these frames are assigned using the counter identified by the Address 1 field and the TID subfield of the QoS Control field of the frame, and that counter is incremented by 1 for each MSDU or A-MSDU corresponding to that < STA MAC Address identified by Address 1, TID> tuple. • Receiver Side • The receiving QoS STA shall keep a cache of recently received < STA MAC Address identified by Address 2, TID, sequence-number, fragment-number>tuples from QoS Data frames from all STAs from which it has received QoS data frames. • A receiving QoS STA shall reject as a duplicate frame any QoS Data frame in which the Retry bit in the Frame Control field is 1 and that matches an < STA MAC Address identified by Address 2, TID, sequence-number, fragment number>tuple of an entry in the cache that contains tuples of that format. Yongho Seok, LG Electronics

  8. Traffic Identifier (TID) • TID identifies the TC or TS to which the corresponding MSDU (or fragment thereof) or A-MSDU belongs • It also identifies the TC or TS of traffic for which a TXOP is being requested, through the setting of TXOP duration requested or queue size • Propose to send only 3 LSBs of the TID with short MAC header • Sufficient for correct operation with EDCA (0—7) • First MSB of TID can be stored at the receiver if HCCA or HEMM is used • Fits perfectly in the available bits in the Frame Control Yongho Seok, LG Electronics

  9. Proposed Spec Change • TID should be included in short MAC frame header • For example, Frame Control field may have TID subfield • that identifies the TC or TS to which the corresponding MSDU (or fragment thereof) or A-MSDU belongs Yongho Seok, LG Electronics

  10. Conclusion • In this contribution, we propose a duplicate detection mechanism of short MAC frame • Also, we propose to include TID field in short MAC header • But, the position of TID field is TBD. It will be decided after finishing all discussion of new MAC features Yongho Seok, LG Electronics

  11. Reference [1] https://mentor.ieee.org/802.11/dcn/12/11-12-0857-00-00ah-short-mac-header-design.pptx Yongho Seok, LG Electronics

  12. Straw Poll • Do you support the duplicate detection mechanism in slide 7 and to include a TID in the short MAC frame header? Yongho Seok, LG Electronics

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