Trigger frame in wireless local area network
The present disclosure provides various aspects related to techniques for generating trigger frames, at an access point (AP), that reduce the overhead associated with triggering an uplink transmission from the wireless station (STA). Features of the present disclosure achieve this by, for example, utilizing a single per-user information field of the trigger to signal a plurality of random access resource units that may be allocated to the one or more STAs in the network. Such a technique is an improvement over the conventional system that require each random access resource unit to be signaled separately in a separate per-user information field (thus increasing the overhead). Additionally, aspects of the present disclosure allow the AP to effectively signal to the STA whether the one or more resources allocated to the at least one STA are a single user resource unit allocation or a multi-user resource unit allocation.
1. A method for wireless communications, comprising:
determining, at an access point (AP), whether to trigger at least one station (STA) for uplink transmission;
generating a trigger frame in response to a determination to trigger the at least one STA, wherein the trigger frame identifies whether one or more resources allocated to the at least one STA are a single user resource unit allocation or a multi-user resource unit allocation;
setting, by the AP, a multi-user (MU) multiple-input and multiple-output (MIMO) long training field (LTF) mode subfield of the trigger frame based on whether the one or more resources allocated to the at least one STA are a single user resource unit allocation or a multi-user resource unit allocation; and
transmitting the trigger frame to the at least one STA.
2. The method of claim 1 , wherein the setting, by the AP, the MU MIMO LTF mode subfield comprises:
setting, by the AP, the MU MIMO LTF mode subfield to a single-stream pilot based on a determination that at least one of the one or more resources allocated to the at least one STA is a single-user resource unit allocation.
3. The method of claim 1 , wherein the setting, by the AP, the MU MIMO LTF mode subfield comprises:
setting, by the AP, the MU MIMO LTF mode subfield to a masked LTF sequence or a single-pilot stream based on a determination that none of the one or more resources allocated to the at least one STA are a single-user resource unit allocation.
4. The method of claim 3 , further comprising:
identifying the MIMO LTF mode in a common information field of the trigger frame.
5. The method of claim 1 , wherein the trigger frame further includes a per-user information field that identifies a plurality of random access resource units allocated to the at least one STA for uplink transmission.
6. The method of claim 1 , further comprising:
determining that one or more resources allocated to the at least one STA are for orthogonal frequency-division multiple access (OFDMA) backoff (OBO);
allocating the one or more resources to association identifier (AID) value of zero; and
receiving from the at least one STA a high efficiency (HE) trigger physical layer convergence procedure protocol data unit (HE_Trig PPDU) with a fixed basic service set (BSS) color information in response to the transmission of the trigger frame.
7. An access point (AP) for wireless communications, comprising:
a memory configured to store instructions for generating trigger frame;
a processor communicatively coupled with the memory, the processor configured to execute the instructions to:
determine, at the AP, whether to trigger at least one station (STA) for uplink transmission, and
generate the trigger frame in response to a determination to trigger the at least one STA, wherein the trigger frame identifies whether one or more resources allocated to the at least one STA are a single user resource unit allocation or a multi-user resource unit allocation;
set a multi-user (MU) multiple-input and multiple-output (MIMO) long training field (LTF) mode subfield of the trigger frame based on whether the one or more resources allocated to the at least one STA are a single user resource unit allocation or a multi-user resource unit allocation; and
a transmitter configured to transmit the trigger frame to the at least one STA.
8. The AP of claim 7 , wherein the processor is configured to set the MU MIMO LTF mode subfield by being configured to:
set the MU MIMO LTF mode subfield to a single-stream pilot based on a determination that at least one of the one or more resources allocated to the at least one STA is a single-user resource unit allocation.
9. The AP of claim 7 , wherein the processor is configured to set the MU MIMO LTF mode subfield by being configured to execute the instructions to:
set the MU MIMO LTF mode subfield to a masked LTF sequence or a single-pilot stream based on a determination that none of the one or more resources allocated to the at least one STA are a single-user resource unit allocation.
10. The AP of claim 9 , wherein the processor is further configured to execute the instructions to:
identify the MIMO LTF mode in a common information field of the trigger frame.
11. The AP of claim 7 , wherein the trigger frame further includes a per-user information field that identifies a plurality of random access resource units allocated to the at least one STA for uplink transmission.
12. The AP of claim 7 , wherein the processor is further configured to execute the instructions to:
determine that one or more resources allocated to the at least one STA are for orthogonal frequency-division multiple access (OFDMA) backoff (OBO); and
allocate the one or more resources to association identifier (AID) value of zero,
wherein the AP further comprises a receiver configured to receive from the at least one STA a high efficiency (HE) trigger physical layer convergence procedure protocol data unit (HE_Trig PPDU) with a fixed basic service set (BSS) color information in response to the transmission of the trigger frame.
13. An apparatus for wireless communications, comprising:
a memory; and
at least one processor communicatively coupled with the memory and configured to:
determine whether to trigger at least one station (STA) for uplink transmission,
generate a trigger frame in response to a determination to trigger the at least one STA, wherein the trigger frame identifies whether one or more resources allocated to the at least one STA are a single user resource unit allocation or a multi-user resource unit allocation,
set a multi-user (MU) multiple-input and multiple-output (MIMO) long training field (LTF) mode subfield of the trigger frame based on whether the one or more resources allocated to the at least one STA are a single user resource unit allocation or a multi-user resource unit allocation; and
output the trigger frame for transmission to the at least one STA.
14. The apparatus of claim 13 , wherein the at least one processor is configured to set the MU MIMO LTF mode subfield of the trigger frame by being configured to:
set the MU MIMO LTF mode subfield to a single-stream pilot based on a determination that at least one of the one or more resources allocated to the at least one STA is a single-user resource unit allocation.
15. The apparatus of claim 13 , wherein the at least one processor is configured to set the MU MIMO LTF mode subfield of the trigger frame by being configured to:
set the MU MIMO LTF mode subfield to a masked LTF sequence or a single-pilot stream based on a determination that none of the one or more resources allocated to the at least one STA are a single-user resource unit allocation.
16. The apparatus of claim 15 , wherein the at least one processor is further configured to:
identify the MIMO LTF mode in a common information field of the trigger frame.
17. The apparatus of claim 13 , wherein the trigger frame further includes a per-user information field that identifies a plurality of random access resource units allocated to the at least one STA for uplink transmission.
18. The apparatus of claim 13 , wherein the at least one processor is further configured to:
determine that one or more resources allocated to the at least one STA are for orthogonal frequency-division multiple access (OFDMA) backoff (OBO);
allocate the one or more resources to an association identifier (AID) value of zero; and
obtain, from the at least one STA, a high efficiency (HE) trigger physical layer convergence procedure protocol data unit (HE_Trig PPDU) with a fixed basic service set (BSS) color information in response to the trigger frame.