November 2005 doc IEEE 802 11 051165 r
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 Joint Proposal MAC Report Date: 2005 -11 -14 Authors: Notice: This document has been prepared to assist IEEE 802. 11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802. 11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures <http: // ieee 802. org/guides/bylaws/sb-bylaws. pdf>, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard. " Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair <stuart. kerry@philips. com> as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802. 11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at <patcom@ieee. org>. Submission 1 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 Submission doc. : IEEE 802. 11 -05/1165 r 0 2 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 Submission doc. : IEEE 802. 11 -05/1165 r 0 3 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 Submission doc. : IEEE 802. 11 -05/1165 r 0 4 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 Submission doc. : IEEE 802. 11 -05/1165 r 0 5 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 Submission doc. : IEEE 802. 11 -05/1165 r 0 6 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 Submission doc. : IEEE 802. 11 -05/1165 r 0 7 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 Submission doc. : IEEE 802. 11 -05/1165 r 0 8 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 Abstract Æ This document provides a detailed explanation of the current (as of 11/14/2005) status of the Joint Proposal MAC draft Submission 9 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 MAC Feature Architecture Submission 10 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 A-MSDU Æ Mechanism to provide enhanced efficiency at the MAC layer ■ ■ ■ Frame Format Length limitations STA Capability • (Mandatory by all HT STA) Submission 11 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 A-MSDU Signaling Bits 0 -3 Bit 4 Bit 5 -6 Bit 7 Bits 8 -15 TID EOSP TXOP / Queue Size Ack Policy A-MSDU Present TXOP limit TXOP duration QAP PS Buffer size Queue Size Æ QOS Control field bit 7 ■ ■ ■ Indicates the presence/absence of A-MSDU Bit 7 is formerly reserved QOS control field exists in DATA type/QOS Subtype frames: • • Submission Qo. S Data+CF-Ack Qo. S Data+CF-Poll Qo. S Data+CF-Ack+CF-Poll 12 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 A-MSDU Frame Format • Efficient Structure • MSDUs of the same TID can be aggregated • MSDUs with differing SA/DA can be aggregated Submission 13 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 A-MSDU DA/SA Fields Subframe Header Fields To DS From DS Address 1 Address 2 Address 3 Address 4 DA SA 0 0 DA SA BSSID Not present Reserved 0 1 DA BSSID Not present Reserved SA 1 0 BSSID SA BSSID Not present DA Reserved 1 1 RA TA BSSID Reserved DA SA Submission 14 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 A-MSDU limits Æ Selectable ■ STA capability: Maximum A-MSDU length • 3839 bytes (default) • 7935 bytes ■ Signaled in HT Capabilities Element • (Coming soon to a draft specification near you) Submission 15 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 A-MSDU Capability Æ Mandatory ■ ■ feature of HT STA, because: Efficiency enhancement is significant TGn PAR throughput requirement needs to be met • A-MSDU provides one of the simplest mechanisms available to assist in achieving the stated requirement • Provides value to many, but not all types of flows outlined in the simulation scenarios ■ Other benefits: • Reduced ISR load at receiver Submission 16 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 Value of A-MSDU – 1 Submission 17 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 Value of A-MSDU - 2 Submission 18 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 PSMP Æ Power ■ Save Multi Poll Mechanism to: • Minimize wake times of power save devices • Enhance efficiency of MAC operations for power save devices – (Provides benefit to all STA in the BSS by having PS STA operate more efficiently) ■ ■ Submission Frame Format Protocol rules 19 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 PSMP Frame Format Submission 20 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 PSMP Sequence Submission 21 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 PSMP MTBA Æ MTBA ■ ■ Submission Multi-TID BA Allows for single frame to respond to (implicit) BAR for multiple TID 22 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 MTBA Frame Format Submission 23 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 PSMP with MTBA Submission 24 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 PSMP Rules Æ Æ AP only includes STA within PSMP if STA is capable, as advertised in HT Capabilities AP obeys minimum DLT 2 ULT per STA ■ Æ Æ AP may set bits in “TID set” field to provide recommendation to STA for use of ULT AP uses EOSP bit to signal end of DATA delivery to STA ■ Æ Within PSMP, implies ACK/BA to appear in ULT vs immediate Service Interval granularity ■ Æ I. e. permission to return to sleep Ack Policy setting in DLT frames is “no explicit acknowledgement” ■ Æ Each STA advertises minimum DLT 2 ULT Advertised by AP to allow STA to determine appropriate TSPEC service interval request to match AP PSMP service intervals PSMP may be used in context of U-APSD or S-APSD Submission 25 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 PSMP resource request example Submission 26 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 PSMP retransmission example Submission 27 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 RD Æ Reverse ■ ■ Direction Protocol Allows a STA to share its TXOP with another STA Grantor Rules Grantee Rules Signaling TBD • Pending further discussions regarding HT Control Field Submission 28 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 RD Basic Rules Transmission by Response initiator An aggregate or non. A response burst consisting of aggregate PPDU one or more aggregated or containing one or more non-aggregated PPDUs unicast frames starting a SIFS after the end addressed to the of the initiator's receiver with the RDG transmission, and lasting no field set to 1. longer than the RDG duration (less a SIFS). The PPDUs of a response burst shall be separated by no more than SIFS. Submission 29 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 RD Initiator rules (1) Æ Æ Æ The initiator shall ensure that its PPDU transmission and any expected/granted responses fit entirely within the current TXOP (this is implicit in 802. 11 e). The responder shall ensure that its PPDU transmission(s) and any expected responses fit entirely within the RDG duration. When the initiator sets the RDG flag to 1, it shall set the AC Constraint field according to the AC of the current EDCA TXOP ■ Æ For HCCA, the initiator shall set the AC Constraint field to the value 4 (any TID). The responder may only transmit Data MPDUs of the same AC as the AC Constraint Field (for values 0 -3) or of any TID (for value 4). Submission 30 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 RD Initiator Rules (2) Æ Æ The responder shall not transmit any MPDUs that are not addressed to the initiator. Subject to TXOP constraints, after transmitting a PPDU containing a reverse direction grant, the initiator may transmit its next PPDU a minimum of a SIFS after receiving a response PPDU with the "More PPDU" flag set to 0. ■ Æ I. e. Initiator still owns TXOP if Grantee is done and TXOP limit has not been exceeded PIFS recovery rule for GRANTOR ■ Submission I. e. if responder does not respond, then Grantor may invoke recovery 31 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 RD Responder rules Æ Æ The first PPDU of any response burst shall contain all response MPDUs (e. g. Ack, BA) as required to respond to the previous PPDU. Only the last PPDU of a response burst may contain an MPDU requiring an immediate response (e. g. Normal ack, BA with immediate response). The presence of any frame in a response PPDU requiring an immediate response is an implicit indication of "More PPDU==0". If the transmission of a frame in a response PPDU requiring an immediate response fails, the responder has to wait until it has the next opportunity to transmit to the initiator before it can retry the transmission. ■ Submission I. e. initiator owns the TXOP and all rights to recovery 32 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 RD Example Exchange Submission 33 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 Value of RD – 1 Submission 34 Fischer (Broadcom), Stephens (Intel) et. al.
November 2005 doc. : IEEE 802. 11 -05/1165 r 0 Value of RD – 2 Submission 35 Fischer (Broadcom), Stephens (Intel) et. al.
- Slides: 35