Group addressed frame reception for non-access point (non-ap) multi-link devices (MLDS)
Certain aspects of the present disclosure relate to wireless communications and, more particularly, to multi-link communications. A method that may be performed by an access point (AP) multi-link device (MLD) includes establishing a plurality of links for communication with a non-AP MLD, wherein one or more non-AP MLDs, including the non-AP MLD, communicate with the AP on each link of the plurality of links and taking one or more actions designed to ensure that the non-AP MLD is able to receive a group addressed frame. The non-AP MLD is operating in an enhanced multi-link single radio (EMLSR) mode.
1 . A method for wireless communication by an access point (AP) multi-link device (MLD), comprising:
establishing a plurality of links for communication with a non-AP MLD, wherein the non-AP MLD communicates with the AP MLD on one or more links of the plurality of links, and wherein the non-AP MLD is operating in an enhanced multi-link single radio (EMLSR) mode; and
taking one or more actions designed to ensure that the non-AP MLD is able to receive a group addressed frame, wherein the one or more actions comprise:
buffering the group addressed frame until a pre-determined time based, at least in part, on the non-AP MLD operating in the EMLSR mode.
2 . The method of claim 1 , wherein the one or more actions further comprise:
transmitting a trigger frame preceding transmission of the group addressed frame, the trigger frame indicating to the non-AP MLD to enter into a full capability state for receiving the group addressed frame via a first link of the plurality of links.
3 . The method of claim 2 , wherein the trigger frame comprises:
a first control type frame, wherein the first control type frame comprises a buffer status report poll (BSRP) or a multiple user (MU)-request to send (RTS) (MU-RTS); or
a second control type frame used to indicate to all non-AP MLDs operating in the EMLSR mode in communication with the AP MLD, including the non-AP MLD, to each enter into the full capability state for receiving the group addressed frame via the first link.
4 . The method of claim 1 , wherein the one or more actions further comprise:
transmitting the group addressed frame via a first link at the pre-determined time.
5 . The method of claim 4 , wherein the pre-determined time comprises a time after a transmission of a delivery traffic indication message (DTIM) beacon during a target beacon transmission time (TBTT) interval configured by the AP MLD for the first link.
6 . The method of claim 1 , wherein the one or more actions further comprise:
initiating a frame exchange sequence on a first link of the plurality of links by transmitting a control type frame to the non-AP MLD via the first link, wherein prior to initiating the frame exchange sequence the AP MLD determines:
a second link of the plurality of links is an anchor link selected by the non-AP MLD; and
the frame exchange sequence does not overlap in time with a group addressed frame transmission on the second link.
7 . The method of claim 1 , wherein the one or more actions further comprise:
determining a first period for a first link of the plurality of links does not overlap in time with a second period for a second link of the plurality of links, wherein the first period is used for transmitting a delivery traffic indication message (DTIM) beacon and the group addressed frame to the non-AP MLD via the first link and the second period is used for transmitting a DTIM beacon and a group addressed frame to the non-AP MLD via the second link; and
refraining from scheduling a frame exchange with the non-AP MLD via:
the second link during the first period, or
the first link during the second period.
8 . The method of claim 7 , wherein when refraining from scheduling the frame exchange with the non-AP MLD, the AP MLD schedules at least one other frame exchange with at least one of:
a non-AP MLD that is not operating in an EMLSR mode; or
a non-AP station (STA).
9 . The method of claim 1 , wherein the one or more actions further comprise:
determining a first period for a first link of the plurality of links does, at least partially, overlap in time with a second period for a second link of the plurality of links, wherein the first period is used for transmitting a delivery traffic indication message (DTIM) beacon and the group addressed frame to the non-AP MLD via the first link and the second period is used for transmitting a DTIM beacon and a group addressed frame to the non-AP MLD via the second link;
determining a duration of the first period is longer than a duration of the second period; and
refraining from scheduling a frame exchange with the non-AP MLD via the second link during a portion of the first period that does not overlap in time with the second period.
10 . The method of claim 9 , wherein when refraining from scheduling the frame exchange with the non-AP MLD via the second link during the portion of the first period that does not overlap in time with the second period, the AP MLD schedules at least one other frame exchange with at least one of:
a non-AP MLD not operating in an EMLSR mode; or
a non-AP station (STA).
11 . The method of claim 1 , wherein the one or more actions further comprise indicating, to the non-AP MLD, relative rates for group addressed frame delivery on different links.
12 . The method of claim 1 , wherein, when an anchor link associated with the non-AP MLD is not known by the AP MLD, the one or more actions further comprise:
determining a target beacon transmission time (TBTT) period configured by the non-AP MLD for each link of the plurality of links;
determining a first link of the plurality of links with the determined TBTT period beginning first in time among each of the determined TBTT periods for each of the links; and
delaying scheduling a frame exchange with the non-AP MLD via each link of the plurality of links, excluding the first link.
13 . A method for wireless communication by a multi-link device (MLD) operating in an enhanced multi-link single radio (EMLSR) mode, comprising:
establishing a plurality of links for communication with an AP MLD, wherein the MLD communicates with the AP MLD on two or more links of the plurality of links; and
taking one or more actions designed to ensure that the MLD is able to receive a group addressed frame, wherein the one or more actions comprise:
receiving, from the AP MLD, a control type frame initiating a frame exchange with the MLD via a first link of the plurality of links; and
when the frame exchange overlaps with the group addressed frame, determining to:
ignore the control type frame.
14 . The method of claim 13 , wherein the group addressed frame comprises, at least one of:
a first bit indicating to the MLD that a subsequent group addressed frame is to be transmitted by the AP MLD; or
a second bit indicating to the MLD that no additional group addressed frames are to be transmitted by the AP MLD, wherein the second bit triggers the MLD to switch from a full capability state to a listening state.
15 . The method of claim 13 , wherein the one or more actions further comprise:
selecting the first link of the plurality of links as an anchor link; and
providing an indication of the anchor link to the AP MLD, wherein the AP MLD initiates a frame exchange sequence on another link of the plurality of links based, at least in part, on the indication.
16 . The method of claim 15 , wherein the indication of the anchor link provided to the AP MLD comprises, an indication of at least one of:
a static anchor link selection by the MLD that is provided during association between the MLD and the AP MLD;
a semi-static anchor link selection by the MLD that is initially provided during the association between the MLD and the AP MLD and subsequently updated transmission of an action frame to the AP MLD; or
a dynamic anchor link selection by the MLD that is dynamically updated via transmission of a control type frame to the AP MLD.
17 . The method of claim 13 , wherein the one or more actions further comprise:
electing to miss another group addressed frame to receive the group addressed frame, wherein the other group addressed frame is transmitted on the first link of the plurality of links and the group addressed frame is transmitted on a second link of the plurality of links.
18 . The method of claim 17 , wherein electing to miss the other group addressed frame to receive the group addressed frame is based, at least in part, on an indication, from the AP MLD, of relative rates for group addressed frame delivery on different links.
19 . The method of claim 17 , wherein electing to miss the other group addressed frame to receive the group addressed frame is based, at least in part, on a priority of one or more frames of a scheduled frame exchange sequence.
20 . The method of claim 13 , wherein the one or more actions further comprise:
initiating a frame exchange sequence with the AP MLD via the first link of the plurality of links, wherein prior to initiating the frame exchange sequence the MLD determines the frame exchange sequence does not overlap in time with a group addressed frame transmission configured for the MLD on a second link of the plurality of links, wherein the second link comprises an anchor link selected by the MLD.
21 . The method of claim 13 , wherein the one or more actions further comprise:
receiving, from the AP MLD, the control type frame initiating a frame exchange sequence with the MLD via the first link of the plurality of links, wherein the frame exchange sequence is for communication of one or more downlink (DL) and uplink (UL) frames; and
when a time difference between when the control type frame is received and a beginning of a target beacon transmission time (TBTT) configured by the AP MLD on a second link of the plurality of links is more than a first threshold amount of time, engaging in the frame exchange sequence, wherein engaging in the frame exchange sequence comprises:
determining, prior to sending a last UL frame of the frame exchange sequence, that the beginning the TBTT configured by the AP MLD on the second link is occurring in a second threshold amount of time; and
transmitting the last UL frame having an A-control field or a power management (PM) bit indicating an unavailability of the MLD based, at least in part, on the determining, wherein the unavailability triggers a termination of the frame exchange sequence.
22 . The method of claim 21 , wherein the last UL frame is a UL data frame or a UL control frame.
23 . The method of claim 13 , wherein the one or more actions further comprise:
determining that a beginning of a target beacon transmission time (TBTT) configured by the AP MLD on the first link of the plurality of links is occurring in a threshold amount of time; and
transmitting, to the AP MLD, an unsolicited frame explicitly indicating an unavailability of the MLD for a second link of the plurality of links, wherein the unavailability indicated in the unsolicited frame indicates to the AP MLD to refrain from initiating the frame exchange with the MLD on the second link.
24 . The method of claim 23 , wherein the unavailability explicitly indicated is indicated via a power management (PM) bit of the unsolicited frame.
25 . The method of claim 23 , wherein the unsolicited frame is a quality of service (QoS) Null frame.
26 . An access point (AP) multi-link device (MLD), comprising:
memory; and
one or more processors coupled to the memory, the one or more processors, individually or collectively, being configured to:
establish a plurality of links for communication with a non-AP MLD, wherein the non-AP MLD communicates with the AP MLD on one or more links of the plurality of links, and wherein the non-AP MLD is operating in an enhanced multi-link single radio (EMLSR) mode; and
take one or more actions designed to ensure that the non-AP MLD is able to receive a group addressed frame, wherein the one or more actions comprise the one or more processors and the memory being configured to:
buffer the group addressed frame until a pre-determined time based, at least in part, on the non-AP MLD operating in the EMLSR mode.
27 . A multi-link device (MLD) operating in an enhanced multi-link single radio (EMLSR) mode, comprising:
memory; and
one or more processors coupled to the memory, the one or more processors, individually or collectively, being configured to:
establish a plurality of links for communication with an AP MLD, wherein the MLD communicates with the AP MLD on two or more links of the plurality of links; and
take one or more actions designed to ensure that the MLD is able to receive a group addressed frame, wherein the one or more actions comprise the one or more processors and the memory being configured to:
receive, from the AP MLD, a control type frame initiating a frame exchange with the MLD via a first link of the plurality of links; and
when the frame exchange overlaps with the group addressed frame, determine to:
ignore the control type frame.