Preemption for latency-sensitive traffic
One example discloses a method of preemption for latency-sensitive traffic for communications between WLAN (wireless local area network) devices, including: receiving, by an access point (AP), a first frame from a first non-access point station (non-AP STA); transmitting, by the AP, a second frame indicating Transmission Opportunity (TXOP) pre-emption information to the first non-AP STA; and transmitting, to a second non-AP STA, a third frame; wherein the third frame includes latency-sensitive frame.
1 . A method of preemption for latency-sensitive traffic for communications between WLAN (wireless local area network) devices, comprising:
receiving, by an access point (AP), a first frame from a first non-access point station (non-AP STA);
transmitting, by the AP, a second frame indicating Transmission Opportunity (TXOP) pre-emption information to the first non-AP STA; and
transmitting, to a second non-AP STA, a third frame;
wherein the third frame includes latency-sensitive frame;
wherein the AP transmits a fourth frame indicating TXOP preemption release to the first non-AP STA after successful transmission of the third frame.
2 . The method of claim 1 :
wherein the TXOP pre-emption information is included in a BlockAck (BA) frame in response to the first frame.
3 . The method of claim 1 :
wherein the TXOP pre-emption information is included in a QoS Null frame; and
wherein the QoS Null frame includes an HE-Control subfield.
4 . The method of claim 1 :
further comprising that the first non-AP STA suspends its frame transmission after receiving the second frame indicating TXOP preemption information.
5 . The method of claim 1 :
further comprising that the first non-AP STA resumes its transmission after receiving the fourth frame from the AP.
6 . The method of claim 1 , further comprising:
obtaining, by the first non-AP STA, a TXOP;
transmitting, by the first non-AP STA to the AP, a first frame indicating a time period;
wherein the time period is allocated for the AP to schedule a downlink or uplink low latency traffic transmission; and
transmitting, by the first non-AP STA to the AP, a second frame that has been buffered at the first non-AP STA during the TXOP, when the time period has expired or a third frame indicating a release of the time period is received.
7 . The method of claim 6 :
wherein the time period is allocated at a beginning of the TXOP or at a beginning of a restricted target wake time service period.
8 . The method of claim 6 :
wherein the time period is less than a predetermined time period within the TXOP.
9 . The method of claim 6 :
wherein the first frame is a QoS Null frame that includes a HE-Control subfield.
10 . The method of claim 6 :
wherein the first frame is transmitted when the TXOP length is longer than a predetermined time period.
11 . The method of claim 6 :
wherein the third frame is a QoS Null frame that includes a HE-Control subfield.
12 . The method of claim 6 :
further comprising, transmitting the first frame, by the non-AP STA, based on group or membership subscription.
13 . The method of claim 12 :
wherein the first or second non-AP STAs belong to a same group or membership.
14 . The method of claim 1 , further comprising:
receiving, by the AP from the first non-AP STA, a first frame indicating a time period;
wherein the time period is allocated within a TXOP for the AP to schedule a downlink or uplink low latency traffic transmission;
transmitting, by the AP, downlink low latency traffic or a trigger frame to solicit uplink low latency traffic from the first non-AP STA or the second non-AP STA during the time period; and
receiving by the AP from the first non-AP STA, a second frame that has been buffered at the first non-AP STA during the TXOP when the time period has expired or a third frame indicating a release of the time period is transmitted.
15 . The method of claim 1 , further comprising:
receiving, by the AP, a first frame from the first non-AP STA, wherein the first frame solicits an immediate control response frame;
transmitting, by the AP, a second frame including a TXOP pre-emption indication to the first non-AP STA, wherein the second frame is the immediate control response frame;
transmitting, by the AP, to the second non-AP STA a third frame, wherein the third frame includes low latency frame; and
transmitting, by the AP, to the first non-AP STA a fourth frame, wherein the fourth frame indicates TXOP return to the first non-AP STA.
16 . The method of claim 15 :
wherein the TXOP pre-emption information is included in at least one of the following immediate response frames in response to the first frame: an Ack frame; a BA (BlockAck) frame; or a CTS frame.
17 . The method of claim 15 :
wherein the TXOP pre-emption indication is indicated in at least one of the following MAC control header field and/or subfield: a duration field; and/or a duration/id field and a more data subfield.
18 . The method of claim 17 :
wherein the duration/id field is set to 0 and/or the more data subfield is set to 1.
19 . A method comprising:
transmitting, to a first non-access point station (non-AP STA), a first frame, wherein the first frame includes non-latency-sensitive frame;
transmitting, to the first non-AP STA, a second frame indicating a PHY Protocol Data Unit (PPDU) pre-emption information; and
transmitting, to a second non-AP STA, a third frame, wherein the third frame includes latency-sensitive frame;
wherein the second frame is a QoS Null frame including an HE-Control subfield.
20 . The method of claim 19 :
wherein the first frame and the second frame are carried in a same PPDU.
21 . The method of claim 19 :
wherein the PPDU pre-emption information includes Ack Policy update information indicating the Ack Policy of the first frame being changed to Block Ack (BA).
22 . The method of claim 19 :
wherein the PPDU pre-emption information includes target recipient information of the third frame indicating whether the second non-AP STA is the same in a same group as the first non-AP STA.
23 . A first WLAN (wireless local area network) device configured as an access point (AP), comprising:
a controller configured define a preemption protocol for latency-sensitive traffic;
wherein the controller is further configured to:
receive a first frame from a first non-access point station (non-AP STA), wherein the first frame is a non-latency-sensitive frame;
transmit a second frame indicating Transmission Opportunity (TXOP) pre-emption information to the first non-AP STA; and
transmit to a second non-AP STA, a third frame, wherein the third frame includes latency-sensitive frame;
wherein the first non-AP STA obtained a TXOP;
wherein the AP is configured to receive from the first non-AP STA a first frame indicating a time period;
wherein the time period is allocated for the AP to schedule a downlink or uplink low latency traffic transmission; and
wherein the AP is configured to receive from the first non-AP STA a second frame that has been buffered at the first non-AP STA during the TXOP, when the time period has expired or after the AP transmits a third frame indicating a release of the time period.