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HCF in an IBSS

HCF in an IBSS. Toshihiro Fujita SONY Corporation. Background. Request for QoS in an IBSS. Outline. 1. Definition of a QIBSS 2. How to determine the QSTA as HC. Definition of a QIBSS. - The IBSS with which the same QoS facility as QBSS is offered by QSTA which has HCF capability.

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HCF in an IBSS

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  1. HCF in an IBSS Toshihiro Fujita SONY Corporation Toshihiro Fujita, SONY

  2. Background Request for QoS in an IBSS Toshihiro Fujita, SONY

  3. Outline 1. Definition of a QIBSS 2. How to determine the QSTA as HC Toshihiro Fujita, SONY

  4. Definition of a QIBSS - The IBSS with which the same QoS facility as QBSS is offered by QSTA which has HCF capability. Toshihiro Fujita, SONY

  5. How to determine the QSTA as HC (1) - The HC in a QIBSS transmits “QoS Parameter Information Frame” periodically. The interval is defined in the frame body. The HC transmits the frame immediately after Beacon frame using PIFS. - The QSTA which is going to enter in a QIBSS searches for a “QoS Parameter Information Frame” during predefined time. If the frame was detected, the QSTA transmits “Association” to HC in order to enter the QIBSS. Transmission of “QoS Parameter Information Frame” will be started, if the frame cannot be detected and the QSTA has HC capability. Toshihiro Fujita, SONY

  6. How to determine the QSTA as HC (2) • If some QSTA which has HC capability has not received “QoS Parameter • Information Frame” during predefined time, these QSTAs try to send • “QoS Parameter Information Frame” with random backoff. • The time is defined as dot11QIBSSLivingtime in MIB. • The QSTA won this arbitration becomes new HC. • - If a HC received “QoS Parameter Information Frame” from other QSTA, • the HC should stop transmission of “QoS Parameter Information Frame”, • except for the case that it is associated with a QSTA. • If a HC received “QoS Parameter Information Frame” from other QSTA, • and both HCs are associated with a QSTA, the HC which received the • frame of number of times predefined should stop transmission of the frame. • The number is defined as dot11QIBSSCoexistnumber in MIB. Toshihiro Fujita, SONY

  7. Beacon generation in a QIBSS • Beacon is generated by HC in a QIBSS. • - QSTAs in a QIBSS should not generate Beacon. Toshihiro Fujita, SONY

  8. Signaling QSTA1 QSTA2(HC) QSTA3(NEW) <---- QoS Parameter Information ----- Association Req -----> <---- Association Res ------- <-------------------------- Beacon ----------------------------> <--------------- QoS Parameter Information ---------------> <------ Association Req ----- (request to enter this QIBSS) ------ Association Res -----> <-------- AddTS Req --------- <-------- AddTS Req -------- --------- AddTS Res --------> ------------ CF Poll ----------> <-------------------------- QoS Data --------------------------- <----------------------- BurstACK Req ----------------------- -------------------------- Burst ACK -------------------------> <--------------------------- Beacon ---------------------------> Toshihiro Fujita, SONY

  9. Additional frame QoS Parameter Information Frame (type=00,subtype=1111) Frame body Order Information Note 1 Interval Interval of this frame (unit:TU) This interval is the multiple of the Beacon Interval basically. 2 Capability information 3 SSID 4 QBSS Load This element is same with QBSS Load in Beacon frame from QAP. 5 QoS Parameter Set This element is same with QoS Parameter Set in Beacon frame from QAP. Toshihiro Fujita, SONY

  10. bits:0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ESS IBSS CF- CF-poll Privacy Short PBCC Channel QoS FEC Bridge rsrv rsrv rsrv rsrv Extended Pollable request preamble agility Portal (0) (0) (0) (0) capability element 0 1 X X X X X X 1 X X 0 0 0 0 X Capability Information in QoS Parameter Information Toshihiro Fujita, SONY

  11. HC(QSTA1) STA1 Association Association QSTA3 STA3 QSTA2 STA2 IBSS/QIBSS • QSTA2 associates with QSTA1(HC) • QSTA3 associates with QSTA1(HC) Toshihiro Fujita, SONY

  12. HC(QSTA1) HC(QSTA4) HC(QSTA1) HC(QSTA4) QSTA3 QSTA6 QSTA3 QSTA6 QSTA2 QSTA5 QSTA2 QSTA5 A QSTA moves to another QIBSS • QSTA5 can’t get QoSPI from QSTA4(HC) • or QSTA5 disassociates from QSTA4(HC) • QSTA5 scans and detects QSTA1(HC) • QSTA5 associates with QSTA1(HC) Toshihiro Fujita, SONY

  13. QSTA1 HC(QSTA4) HC(QSTA1) HC(QSTA4) QSTA3 QSTA6 QSTA3 QSTA6 QSTA2 QSTA2 QSTA5 QSTA5 Merge • QSTA1(HC) detects QSTA4(HC) • and QSTA4(HC) detects QSTA1(HC) • QSTA1 stop transmission of QoSPI • QSTA1 associates with QSTA4(HC) • - QSTA2 scans and detects QSTA4(HC) • QSTA3 scans and detects QSTA4(HC) • QSTA2 associates with QSTA4(HC) • QSTA3 associates with QSTA4(HC) • QSTA1 requests Tspec to QSTA4(HC) Toshihiro Fujita, SONY

  14. QSTA1 HC(QSTA4) HC(QSTA4) HC(QSTA1) QSTA6 QSTA3 QSTA6 QSTA3 QSTA2 QSTA2 QSTA5 QSTA5 Sprit • QSTA1 can’t get QoSPI from QSTA4(HC) • or QSTA1 disassociates from QSTA4(HC) • - QSTA3 can’t get QoSPI from QSTA4(HC) • or QSTA3 disassociates from QSTA4(HC) • - QSTA1 scans • QSTA3 scans • QSTA1 transmits QoSPI • QSTA3 associates with QSTA1(HC) • QSTA1 requests Tspec Toshihiro Fujita, SONY

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