Null data packet announcement (NDPA) frame indication

Abstract

The present disclosure provides methods and apparatus related to NDPA frame indication.SOLUTION: The method includes sending, by an access point (AP) to one or more stations (STAs), a request for channel state information (CSI). The request includes a null data packet announcement (NDPA) frame including a common information field. The common information field includes an indicator of whether trigger-based (TB) sounding or non-trigger-based (non-TB) is being used. Then, the method includes receiving, by the AP from the one or more STAs, a CSI feedback response based on the request. The common information field may be an alternative name null data packet announcement (NDPA) variant field and the indicator may utilize one bit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the field of communication networks, and in particular to methods and frame formats associated with NDPA frame indication. [Background technology]

[0002] (cross reference) This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 311,227, entitled "NULL DATA PACKET ANNOUNCEMENT (NDPA) FRAME INDICATION," filed February 17, 2022, and U.S. Non-Provisional Patent Application No. 18 / 107,568, entitled "NULL DATA PACKET ANNOUNCEMENT (NDPA) FRAME INDICATION," filed February 9, 2023, the contents of which are incorporated herein by reference in their entireties.

[0003] The existing Null Data Packet Announcement (NDPA) frame format in the IEEE 802.11be (11be) draft standard can indicate a limited number of NDPA variants. The existing NDPA frame can be used to indicate several communication parameters, including station (STA) and sounding parameters used to configure and adjust the communication channel.

[0004] Many wireless local area network (WLAN) devices include multiple antennas and implement multiple-input multiple-output (MIMO) techniques to improve system throughput. The ability to communicate effectively relies on obtaining accurate channel state information (CSI) that describes the characteristics of the communication link. During the channel sounding process, a sequence of data is transmitted over the target channel to the responder. Based on the received signal, the responder estimates the CSI and sends this information back to the transmitter. Both trigger-based (TB) and non-trigger-based (non-TB) sounding may be used.

[0005] During the channel sounding process, parameters such as the responder's transmit (Tx) power or feedback bandwidth may be sent in the station (STA) information field of the trigger frame following the Null Data Packet (NDP) in the case of TB sounding. In the case of non-TB sounding, the responder's Tx power may be indicated in a common field, or the feedback bandwidth parameter may be aligned with the bandwidth of the NDPA and NDP frames. This may result in redundant information being sent in the STA information field, which may be inefficient.

[0006] Therefore, what is needed is a method and frame format that avoids or mitigates one or more limitations of the prior art.

[0007] This background information is provided to identify information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should it be construed, that any of the preceding information constitutes prior art against the present invention. Summary of the Invention

[0008] The present disclosure provides methods and apparatus related to using the common information field of an NDPA frame to indicate whether TB sounding or non-TB sounding is being used. In an embodiment, a one-bit TB / non-TB sounding indication bit may be added to the common field of the NDPA frame. In this way, the NDPA can distinguish between TB sounding and non-TB sounding. In another embodiment, some parameters currently conveyed in the STA information field, such as Tx power or feedback bandwidth, may be split into other fields, such as the common information field, or split into frames, such as a trigger frame or a measurement setup frame.

[0009] A first aspect of the present disclosure may provide a method including sending, by an access point (AP) to one or more stations (STAs) a request for channel state information (CSI), the request including a null data packet announcement (NDPA) frame. The NDPA frame includes a common information field including an indicator of whether trigger-based (TB) sounding or non-trigger-based (non-TB) sounding is being used. The method then includes receiving, by the AP, a CSI feedback response from the one or more STAs based on the request.

[0010] In some embodiments, the common information field is a Null Data Packet Announcement (NDPA) variant field.

[0011] In some embodiments, the indicator utilizes one bit.

[0012] According to a second aspect, there is provided an apparatus, the apparatus including: a memory configured to store a program; and a processor configured to execute the program stored in the memory, the processor being configured to perform the method of the first aspect described herein when the program stored in the memory is executed. The apparatus may be an access point (AP).

[0013] According to a third aspect, a computer-readable medium is provided, the computer-readable medium storing program code executed by a device, the program code being used to implement the method of the first aspect described herein. The device may be a processor, CPU, controller, etc. of an access point (AP).

[0014] According to a fourth aspect, there is provided a chip, the chip including a processor and a data interface, the processor reading instructions stored in a memory by using the data interface to perform the method of the first aspect described herein, the chip may be a processor, controller, etc. of an access point (AP).

[0015] Other aspects of the present disclosure provide apparatuses and systems configured to implement the methods disclosed herein. For example, wireless stations (STAs) and access points (APs) can be configured with machine-readable memories containing instructions that, when executed by processors of these devices, configure the devices to perform the methods disclosed herein.

[0016] The embodiments are described above in conjunction with the aspects of the invention in which they can be implemented. Those skilled in the art will understand that the embodiments can be implemented in conjunction with the aspect with which they are described, but can also be implemented with other embodiments of that aspect. When embodiments are mutually exclusive or mutually exclusive, it will be apparent to those skilled in the art. Some embodiments may be described in relation to one aspect, but may also be applicable to other aspects, as will be apparent to those skilled in the art. [Brief explanation of the drawings]

[0017] Further features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.

[0018] [Figure 1] FIG. 1 illustrates an NDPA frame format according to an embodiment. [Figure 2] FIG. 10 illustrates common information that may be carried in an NDPA variant field, according to an embodiment. [Figure 3] A diagram showing TB / non-TB sounding bits included in an NDPA variant field according to an embodiment. [Figure 4] A diagram showing an example of an alternative NDPA frame format according to an embodiment of the present disclosure. [Figure 5] A figure showing another example of an extended NDPA frame format according to an embodiment of the present disclosure. [Figure 6] A figure showing another example of an extended NDPA frame format according to an embodiment of the present disclosure. [Figure 7] FIG. 10 illustrates an example of a vendor-specific NDPA frame extension according to an embodiment of the present disclosure. [Figure 8] FIG. 10 illustrates another example of a vendor-specific NDPA frame extension according to an embodiment of the present disclosure. [Figure 9] FIG. 1 illustrates a non-TB sensing sounding procedure according to an embodiment of the present disclosure. [Figure 10]FIG. 1 illustrates a TB sensing sounding procedure according to an embodiment of the present disclosure. [Figure 11] FIG. 1 is a detailed view of the NDPA sounding stage, according to an embodiment of the present disclosure. [Figure 12] 1 is a schematic diagram of an electronic device capable of performing any or all of the operations of the above methods and features explicitly or implicitly described herein, according to different embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] It should be noted that throughout the accompanying drawings, like features are identified by like reference numerals.

[0020] The channel state information (CSI) feature was first introduced in the IEEE 802.11n standard in the context of multiple-input multiple-output (MIMO) functionality. As will be understood by those skilled in the art, the CSI training sequence may be designed to measure the channel characteristics between a transmitter and a receiver. The CSI may represent how an electromagnetic signal propagates from a transmitter to a receiver and the combined effects of signal scattering, fading, and power attenuation over distance.

[0021] CSI may reflect wireless signal propagation characteristics of a link from a transmitter to a receiver at a particular carrier frequency. A sounding procedure may be used to perform CSI measurements, and this procedure may vary depending on whether a trigger-based (TB) sounding procedure or a non-trigger-based (non-TB) sounding procedure is used. Embodiments described herein provide methods and apparatus related to using a common information field in an NDPA frame to indicate whether TB sounding or non-TB sounding is being used.

[0022] In an embodiment, a one-bit TB / non-TB sounding indication bit may be added to the common field of the NDPA frame. In this way, the NDPA can distinguish between TB and non-TB sounding cases. In another embodiment, some parameters currently conveyed in the STA information field, such as Tx power or feedback bandwidth, may be split into other fields, such as the common information field, or split into frames, such as the trigger frame or measurement setup frame.

[0023] 1 illustrates an NDPA frame format according to an embodiment. The NDPA frame format 100 comprises fields including a physical layer (PHY) header 102, a frame control 104, a duration 106, a receiver address (RA) 108, a transmitter address (TA) 110, a sounding dialogue token 120, an NDPA variant 402, one or more station (STA) information 122 (e.g., STA info 1, ..., STA info n), and a frame check sequence (FCS) 128. With reference to the NDPA frame format 100, the portion of the frame including the frame control field 104, the duration field 106, the RA field 110, and the TA field 110 may be referred to as a MAC header 130.

[0024] Each field in the frame format 100 is assigned a specific size. The frame control field 104 and duration field are each assigned two octets. The RA field 108 and TA field 110 are each assigned six octets. The sounding dialog token field 120 is assigned one octet. The NDPA variant field and each of the STA information fields (e.g., STA info 1, ..., STA info n) may be assigned four octets. Additionally, the FCS field is assigned four octets. Each octet is eight bits, or one byte.

[0025] In an embodiment, the NDPA variant field 402 may be used to indicate information common to all STAs, and each STA information field 122 may be used to indicate information related to an individual STA. The NDPA variant field 402 may alternatively be referred to as a "common information" field or a "special STA information" field.

[0026] FIG. 2 illustrates common information that may be carried in the NDPA variant field 402, according to an embodiment. The "Common Information Present" subfield may be used to indicate whether the NDPA variant field 402 is present. If the NDPA variant field 402 is not present, it may be replaced by or used as the STA information field 122. In embodiments in which the NDPA variant field 402 is used as a special STA information field, a dummy association ID (AID) may be used to indicate the presence of the common information subfield. The measurement setup ID field of the common information field may be used to indicate the measurement setup ID of the NDPA frame. The sounding dialog token number may be used to indicate the measurement instance ID. In embodiments, the measurement instance ID may also be carried in the common information field. An NDPA version ID and a disambiguation bit may also be included. The disambiguation bit may include one bit per two bytes after the first two bytes in the case of the special STA information field, or one bit per two bytes in other cases.

[0027] FIG. 3 illustrates how a TB / non-TB sounding bit 352 may be included in an NDPA variant field 402, according to an embodiment. The one-bit TB / non-TB sounding indication bit 352 may be included in the NDPA variant field 402 to allow the NDPA frame 100 to indicate whether TB sounding or non-TB sounding is being used. The indication may also allow some information and parameters, such as Tx power or feedback bandwidth, to be moved from the STA information field 122 to some other field, such as a common information field, or to another frame, such as a trigger frame or measurement setup frame. A single bit may be used to indicate a TB sounding NDPA or a non-TB sounding NDPA, although, as is known in the art, more bits may be used to encode the two possibilities. In an embodiment, a "0" may be used to indicate the TB sounding case, and a "1" may be used to indicate the non-TB sounding case. Alternatively, a "1" may be used to indicate a TB sounding case, and a "0" may be used to indicate a non-TB sounding case.

[0028] 4 illustrates an example of an alternative NDPA frame format according to an embodiment of the present disclosure. The extended NDPA frame format 400 may comprise one or more fields including the following: PHY header 102, frame control 104, duration 106, RA 108, TA 110, sounding dialogue token 300, NDPA variant 402, one or more STA information 122 (e.g., STA info 1, ..., station info n), and FCS 128. The NDPA variant field 402 may be 2 bytes in some embodiments, although other sizes (e.g., 4 bytes, etc.) may be suitable, as will be appreciated by those skilled in the art.

[0029] In some embodiments, the indication of the presence of the NDPA variant field (via 6 bits B2 through B7 of the sounding dialog token field 300) may further indicate the presence of another field (in addition to the NDPA variant field), which may be referred to as a sounding instance identifier (ID) field 404. As shown, the sounding instance ID 404 may be between the sounding dialog token field 300 and the NDPA variant field 402. The sounding instance ID 404 may indicate sounding dialog token number information. In such embodiments, if the sounding instance ID 404 provides such information, the NDPA variant field 402 need not indicate sounding dialog token ID information. In some embodiments, the sounding instance ID 404 may be 1 byte.

[0030] 5 illustrates another example of an extended NDPA frame format according to an embodiment of the present disclosure. The NDPA frame format 700 may comprise fields including one or more of the PHY header field 102, the frame control field 702, the duration field 106, the RA field 108, the TA field 110, the sounding dialog token field 704, one or more STA information fields 122, and the FCS field 128, as shown.

[0031] As will be appreciated by those skilled in the art, the 4-bit subtype subfield of the frame control field 702 (in the MAC header) runs out of control frame subtypes. However, three frame control field subtypes, namely, 0000, 0001, and 0010, are still reserved. Embodiments may provide for using one of these remaining reserved frame control subtypes to define an extended control frame. The extended control frame may be referred to as an "NDPA" control frame, e.g., NDPA frame format 700.

[0032] In embodiments, the frame control field 702 may comprise a subtype value (by using one of the three provided frame control field subtypes) to indicate the extended NDPA frame format 700. In some embodiments, the sounding dialog token field 704 may be two bytes in size (a one-byte increase compared to the sounding dialog token field 120 of FIG. 1). In this case, the sounding dialog token field may be called or renamed a common field.

[0033] In some embodiments, the first byte (8 bits) of the sounding dialog token field 704 may be used to indicate an NDPA variant. In some embodiments, one bit of the first eight bits may be reserved to indicate an extension of the NDPA variant (thereby accommodating a further extension to indicate an NDPA variant). In embodiments in which one bit (e.g., the eighth bit of the first eight bits of the sounding dialog token field 704) is reserved to indicate an extension, the remaining seven bits (e.g., the first seven bits of the sounding dialog token field 704) may be used to indicate the NDPA variant. In some embodiments, the remaining eight bits (second byte) of the sounding dialog token field 704 may be used to indicate a sounding dialog token number index.

[0034] In some embodiments, as illustrated by the dashed lines, an alternative to the sounding dialogue token field 704 may be an NDPA variant field 706 and a sounding instance ID field 708. Thus, in some embodiments, instead of the sounding dialogue token field 704, the NDPA frame format 700 may comprise an 8-bit NDPA variant field 706 followed by an 8-bit sounding instance ID field 708, as shown. The NDPA variant field 706 may include a 1-bit TB / non-TB sounding indication bit 352 to allow the NDPA frame 700 to indicate whether TB sounding or non-TB sounding is being used.

[0035] FIG. 6 illustrates another example of an extended NDPA frame format according to an embodiment of the present disclosure.

[0036] In some embodiments, a control frame extension may be used to define an extended NDPA control frame. As will be appreciated by those skilled in the art, the frame control field comprises a control subtype (e.g., control frame extension) to indicate future control frames. Embodiments may provide for the use of the control frame extension to create future modified variants of NDPA control frames.

[0037] The NDPA frame format 800 may comprise fields including one or more of the following, as shown: a PHY header field 102, a frame control field 802, a duration field 106, an RA field 108, a TA field 110, an extended subtype field 803, a sounding dialog token field 804, one or more STA information fields 122, and an FCS field 128.

[0038] The sounding dialog token field 804 of the NDPA frame format 800 may be similar to the sounding dialog token field 704 of the NDPA frame format 700. The NDPA variant field 806 may be similar to the NDPA variant field 706. The NDPA variant field 806 may include a one-bit TB / non-TB sounding indication bit 352 to allow the NDPA frame 800 to indicate whether TB sounding or non-TB sounding is being used. The sounding instance ID field 808 may be similar to the sounding instance ID field 708.

[0039] In some embodiments, the size of the sounding dialog token field 804 may be two bytes. In some embodiments, the first byte (8 bits) of the sounding dialog token field 804 may be used to indicate an NDPA variant. In some embodiments, one bit of the first eight bits may be reserved to indicate an extension of the NDPA variant (thereby accommodating a further extension to indicate an NDPA variant). In embodiments in which one bit (e.g., the eighth bit of the first eight bits of the sounding dialog token field 804) is reserved to indicate an extension, the remaining seven bits (e.g., the first seven bits of the sounding dialog token field 804) may be used to indicate the NDPA variant.

[0040] In some embodiments, as illustrated by the dashed lines, an alternative to the sounding dialogue token field 804 may be an NDPA variant field 806 and a sounding instance ID field 808. Thus, in some embodiments, instead of the sounding dialogue token field 804, the NDPA frame format 800 may comprise an 8-bit NDPA variant field 806 followed by an 8-bit sounding instance ID field 808, as shown. The NDPA variant field 806 may include a 1-bit TB / non-TB sounding indication bit 352 to allow the NDPA frame 800 to indicate whether TB sounding or non-TB sounding is being used.

[0041] 7 illustrates an example of a vendor-specific NDPA frame extension according to an embodiment of the present disclosure. NDPA frame format 900 may be similar to NDPA frame format 400, except that the first octet of NDPA variant field 902 may include a one-bit TB / non-TB sounding indication bit 352 to enable NDPA frame 900 to indicate whether TB sounding or non-TB sounding is being used.

[0042] 8 illustrates another example of a vendor-specific NDPA frame extension in accordance with an embodiment of the present disclosure. NDPA frame format 1000 may be similar to NDPA frame format 700, except that the first octet of sounding dialog token 704, i.e., the first octet of NDPA variant field 1006, may be used to indicate a vendor-specific extension. As discussed with reference to FIG. 5, in some embodiments, sounding dialog token field 704 may be replaced with NDPA variant field 1006 and sounding instance ID field 708. NDPA variant field 1006 may include a one-bit TB / non-TB sounding indication bit 352 to enable NDPA frame 1000 to indicate whether TB sounding or non-TB sounding is being used.

[0043] 9 illustrates a non-TB sensing sounding procedure according to an embodiment of the present disclosure. The procedure 1100 may be between an access point (AP) 1102 and a station (STA) 1108. While one AP 1102 is shown, those skilled in the art will understand that multiple APs may be included in the procedure 1100. In the procedure 1100, the AP 1102 may be considered the "sensing responder," and the STA 1108 may be considered the "sensing initiator."

[0044] In an embodiment, the STA 1108 may send a sensing NDPA frame 1122 that may be received by the AP 1102. The NDPA frame 1122 may correspond to an NDPA frame format 100, 400, 700, 800, 900, or 1000 described herein. The NDPA frame 1122 may include a TB / non-TB sounding indication bit 352, indicating that a non-TB sensing sounding procedure is being used. A shortest inter-frame space (SIFS) time unit after sending the NDPA 1122, the STA 1108 may send an initiator to responder (I2R) NDP frame 1126. A shortest inter-frame space (SIFS) time unit after sending the NDP 1126, the AP may respond with a responder to initiator (R2I) NDP frame 1130 to complete the procedure.

[0045] 10 illustrates a TB sensing sounding procedure according to an embodiment of the present disclosure. The procedure 1300 may be between an access point (AP) 1102 and one or more stations (STAs). The STAs may include a group of sensing transmitters 1304, including sensing responders STA1 1306 and STA2 1308. The STAs may also include a group of sensing receivers 1310, including sensing responder STAs STA3 1312, STA4 1314, and STA5 1316. While one AP 1102 is illustrated, those skilled in the art will appreciate that multiple APs may be included in the procedure 1300. In the procedure 1300, the TB / non-TB sounding indication bit 352 indicates that the TB sensing sounding procedure is being used.

[0046] In the polling phase, the AP 1102 may send a sensing polling trigger frame. A gap of one single inter-frame space (SIFS) time units may occur between transmissions from the AP 1102, and the group of STAs and each STA may respond by sending a clear to send (CTS) frame. In the TF sounding phase, the AP 1102 may send a sensing sounding trigger frame, and the sensing transmitters 1304 STA1 1306 and STA2 1308 may respond with an R2I NDP frame. In the NDPA sounding phase, the AP 1102 may send a sensing NDPA frame followed by an SIFS time unit followed by an I2R NDP frame.

[0047] 11 shows a detailed diagram of the NDPA sounding stage according to an embodiment of the present disclosure. The AP 1102 sends an NDPA frame 1422, which may include a TB / non-TB sounding indication bit 352 to indicate whether a TB sensing sounding procedure or a non-TB sounding procedure is being used. The AP 1102 may then send an I2R NDP frame 1426, followed by a sensing trigger report frame 1430. STA3 1412 and STA4 1414 may then respond with a CSI report frame 1434 and a CSI report frame 1436, respectively.

[0048] 12 is a schematic diagram of an electronic device 1200 that may perform any or all of the operations of the above methods and features explicitly or implicitly described herein, according to different embodiments of the present invention. For example, a computer with network capabilities may be configured as electronic device 1200. In some embodiments, electronic device 1200 may be a user equipment (UE), an AP, a STA, or the like, as will be appreciated by those skilled in the art.

[0049] As shown, electronic device 1200 may include a processor 1210, such as a central processing unit (CPU) or a specialized processor such as a graphics processing unit (GPU) or other such processor unit, memory 1220, non-transitory mass storage device 1230, input / output interface 1240, network interface 1250, and transceiver 1260, all communicatively coupled via a bidirectional bus 1270. According to particular embodiments, any or all of the depicted elements may be utilized, or only a subset of these elements may be utilized. Furthermore, electronic device 1200 may include multiple instances of a particular element, such as multiple processors, memories, or transceivers. Elements of a hardware device may also be directly coupled to other elements without a bidirectional bus. In addition to, or in place of, the processor and memory, other electronic circuitry, such as integrated circuits, may be employed to perform the necessary logical operations.

[0050] The memory 1220 may include any type of non-transitory memory, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), read-only memory (ROM), any combination of the foregoing, or the like. The mass storage element 1230 may include any type of non-transitory storage device, such as a solid-state drive, a hard disk drive, a magnetic disk drive, an optical disk drive, a USB drive, or any computer program product configured to store data and machine-executable program code. According to particular embodiments, the memory 1220 or the mass storage device 1230 may record statements and instructions executable by the processor 1210 to perform any of the foregoing method operations described above.

[0051] Embodiments of the present invention can be implemented using electronic hardware, software, or a combination thereof. In some embodiments, the present invention is implemented by one or more computer processors executing program instructions stored in memory. In some embodiments, the present invention is implemented partially or wholly in hardware, using, for example, one or more field programmable gate arrays (FPGAs) or application specific integrated circuits (ASICs) to rapidly perform processing operations.

[0052] Although specific embodiments of the present technology have been described herein for illustrative purposes, it should be understood that various modifications can be made without departing from the scope of the present technology. Accordingly, the specification and drawings are to be considered merely as illustrative of the present invention as defined by the appended claims, and are intended to encompass any and all modifications, variations, combinations, or equivalents that fall within the scope of the present invention. In particular, it is within the scope of the present technology to provide a computer program product or program element, or a program storage or memory device, such as a magnetic or optical wire, tape or disk, or the like, for storing machine-readable signals, for controlling the operation of a computer in accordance with the methods of the present technology, and / or for configuring some or all of its components in accordance with the systems of the present technology.

[0053] The operations associated with the methods described herein may be implemented as coded instructions in a computer program product. In other words, the computer program product is a computer-readable medium having software code recorded thereon for performing the methods when the computer program product is loaded into a memory and executed on a microprocessor of a wireless communication device.

[0054] Furthermore, each operation of the method may be performed by any computing device, such as a personal computer, a server, a personal digital assistant (PDA), or the like, according to one or more program elements, modules, or objects, or according to one or more portions thereof, created from any programming language, such as C++, Java, or the like. Additionally, each operation, or a file, object, or the like implementing each operation, may be performed by dedicated hardware or circuit modules designed for that purpose.

[0055] Through the description of the foregoing embodiments, the present invention may be implemented using hardware alone or using software and a required universal hardware platform. Based on this understanding, the technical solutions of the present invention may be embodied in the form of a software product. The software product may be stored on a non-volatile or non-transitory storage medium, which may be a compact disc read-only memory (CD-ROM), a USB flash disk, or a removable hard disk. The software product includes a number of instructions that enable a computing device (a personal computer, a server, or a network device) to execute the methods provided in the embodiments of the present invention. For example, such execution may correspond to simulating the logic operations described herein. The software product may additionally or alternatively include a number of instructions that enable a computing device to execute operations for configuring or programming a digital logic device according to the embodiments of the present invention.

[0056] While the invention has been described with respect to particular features and embodiments thereof, it will be apparent that various modifications and combinations can be made thereto without departing from the invention. Accordingly, the specification and drawings are to be considered merely as illustrative of the invention as defined by the appended claims, and it is intended to cover any and all modifications, variations, combinations or equivalents that fall within the scope of the invention.

Claims

1. sending, by an access point (AP) to one or more stations (STAs), a request for channel state information (CSI), the request comprising a null data packet announcement (NDPA) frame including a common information field, the common information field including an indicator of whether trigger-based (TB) sounding or non-trigger-based (non-TB) sounding is being used; receiving, by the AP, a CSI feedback response from the one or more STAs based on the request; A method comprising:

2. The method of claim 0, wherein the common information field is a Null Data Packet Announcement (NDPA) variant field.

3. The method of claim 1 or 2, wherein the indicator indicates that non-TB sounding is being used and the common information field includes a transmit (Tx) power parameter.

4. The method of claim 1 , wherein the indicator indicates that non-TB sounding is being used and the common information field includes a feedback bandwidth parameter.

5. The method of claim 1 , wherein the indicator utilizes one bit.

6. 1. An apparatus comprising: at least one processor; and at least one machine-readable medium storing executable instructions that, when executed by the at least one processor, cause the apparatus to: Sending a request for channel state information (CSI) by an access point (AP) to one or more stations (STAs), the request including a null data packet announcement (NDPA) frame including a common information field, the common information field including an indicator of whether trigger-based (TB) sounding or non-trigger-based (non-TB) sounding is being used; receiving, by the AP, a CSI feedback response from the one or more STAs based on the request; A device configured as follows.

7. 7. The apparatus of claim 6, wherein the common information field is a Null Data Packet Announcement (NDPA) variant field.

8. The apparatus of claim 6 or 7, wherein the indicator indicates that non-TB sounding is being used and the common information field includes a transmit (Tx) power parameter.

9. The apparatus of claim 6 , wherein the indicator indicates that non-TB sounding is being used, and the common information field includes a feedback bandwidth parameter.

10. 10. The apparatus of claim 6, wherein the indicator utilises one bit.

11. A non-transitory computer-readable medium storing executable instructions that, when executed by a processor of a device, cause the device to: Sending a request for channel state information (CSI) by an access point (AP) to one or more stations (STAs), the request including a null data packet announcement (NDPA) frame including a common information field, the common information field including an indicator of whether trigger-based (TB) sounding or non-trigger-based (non-TB) sounding is being used; receiving, by the AP, a CSI feedback response from the one or more STAs based on the request; A non-transitory computer-readable medium configured to:

12. 12. The non-transitory computer-readable medium of claim 11, wherein the common information field is a Null Data Packet Announcement (NDPA) variant field.

13. The non-transitory computer-readable medium of claim 11 or 12, wherein the indicator indicates that non-TB sounding is being used and the common information field includes a Tx power parameter.

14. The non-transitory computer-readable medium of claim 11 , wherein the indicator indicates that non-TB sounding is being used and the common information field includes a feedback bandwidth parameter.

15. The non-transitory computer-readable medium of claim 11 , wherein the indicator utilizes one bit.

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