Proposed Modifications to January 2003 Proposed Modifications to 802.11e-D4.0 Group ACK Carlos Rios RiosTek LLC

January 2003 D4.0 Group ACK Summary Group ACK per 802.11e-D4.0 is a relatively involved protocol to allow a QSTA to burst transmissions to another QSTA while deferring any and all associated ACKs until after a later (Group) ACK request. Upon association, sender gleans from (Association frame) Capabilities Info field that candidate receiver is capable of Group ACK Group ACK is set up, characterized and torn down with Action Frames: Sender transmits ADDGA Request to set up GA with receiver Receiver responds with ADDGA Response to announce its GA capabilities Sender and Receiver define Tx, Rx Buffer sizes and otherwise prep for GA DELGA Request lets the sender tear down previously established GA capability Once GA is set up, sender advertises any transmitted frames subject to GA by setting an appropriate flag in the packet MAC Header QOS Control field Keeps track of all buffer sizes, etc so to not send too many packets, etc GA-able frames are burst transmitted, separated by SIFS if within one TXOP Done transmitting the burst, Sender issues GroupACK Request Control frame Receiver immediately responds with a Group ACK or an ACK The ACK lets him mark time until he’s done preparing a real Group ACK Real Group ACK ready, receiver transmits it ASAP (during his own TXOP) Sender needs to ACK this Group ACK Sender can then initiate another burst at his convenience

Unbundle Group ACK from QoS January 2003 Unbundle Group ACK from QoS GA functionality should be available to all stations, not just QSTAs Group ACKs should be allowed under DCF rules Don’t use QOS Control field to advertise GA parameters Replace “Order” bit (B15) in MAC Header Frame Control field with a “GA” bit set upon a Group ACK-able packet transmission Reclassify ADDGA Request, ADDGA Response and DELGA Request as new category “GA Action Frames” Remove them from the QOS Action Frame class As TXOPs don’t apply in DCF, finesse the SIFS interframe spacing issue Use SIFS to separate GA-able packets whenever possible If don’t/can’t use SIFS, accept possibility of losing medium access to DCF contender

Proposed Group ACK Modifications January 2003 Proposed Group ACK Modifications Modified Group ACK is a relatively involved protocol to allow a STA to burst transmissions to another STA while deferring any and all corresponding ACKs until after a later (Group) ACK request. Upon association, sender gleans from (Association frame) Capabilities Info field that candidate receiver is capable of Group ACK Group ACK is set up, characterized and torn down with Action Frames: Sender transmits ADDGA Request to set up GA with receiver Receiver responds with ADDGA Response to announce its GA capabilities Sender and Receiver define Tx, Rx Buffer sizes and otherwise prep for GA DELGA Request lets the sender tear down previously established GA capability Once GA is set up, sender advertises any transmitted frames subject to GA by setting an appropriate flag in the packet MAC Header Frame Control field Keeps track of all buffer sizes, etc so to not send too many packets, etc Group ACKable frames are transmitted, separated at a minimum by SIFS Done transmitting the burst, Sender issues GroupACK Request Control frame Receiver immediately responds with a Group ACK or an ACK The ACK lets him mark time until he’s done preparing a real Group ACK Real Group ACK ready, receiver transmits it as soon as possible Sender needs to ACK this Group ACK Sender can then initiate another burst at his convenience

Proposed Group ACK Modifications Summary January 2003 Proposed Group ACK Modifications Summary The modified GA remains a complicated protocol, but now allows non-QoS STAs to burst transmissions to each other. Candidate normative text revisions to 802.11e-D4.0 are contained in document 03/052r0 “QSTA” replaced by “STA” throughout Additions, clarifications regarding GA under DCF FCS “Order” bit replaced by a “No immediate ACK” bit GA frames moved from the “QoS action” category to a new “GA action” category Substantial revisions made to section 7, 9.11, 10.3.16 and 11.5

January 2003 Motion “Move to instruct the Technical Editor to work with the author and the Group ACK Ad Hoc group to incorporate modifications contained in document 03/52r0 into the successor to 802.11e-D4.0”