KR20220001412A - Apparatus and method for supporting efficient channel state information feedback of users in a wireless local area network system - Google Patents

Abstract

Disclosed are an apparatus for supporting efficient channel state information feedback of users in a wireless local area network (WLAN) system to increase a data transmission reception rate and a method thereof. According to the technical idea of the present invention, a baseband circuit provided in a transmission apparatus of the WLAN system comprises: a storage unit; a control unit to write or read data to the storage unit; and a signal processing unit controlled by the control unit and generating a physical layer convergence protocol (PLCP) protocol data unit (PPDU) including a preamble and a payload, wherein a data field of the payload includes a null data packet announcement (NDPA) frame. The NDPA frame includes a medium access control (MAC) header and a frame body. The frame body includes a first user information field applied to a reception device to receive the PPDU from the transmission device. The first user information field includes: a partial bandwidth information subfield including subcarrier index information corresponding to a partial bandwidth designated as a channel feedback section of the reception device; and an additional partial bandwidth presence subfield indicating whether an additional partial bandwidth designated as a channel feedback section of the reception device in addition to the partial bandwidth is present.

Description

Apparatus and method for supporting user's efficient channel state information feedback in WLAN system

The technical idea of the present disclosure relates to an apparatus and method for supporting efficient channel state information feedback of a user in a WLAN system.

A wireless local area network (WLAN) is a technology that connects two or more devices to each other using a wireless signal transmission method. Currently, most WLAN technologies are based on the IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard. The 802.11 standard has evolved into 802.11b, 802.11a, 802.11g, 802.11n, 802.11ac and 802.11ax, and currently transmits up to 1 Gbyte/s using Orthogonal frequency-division multiplexing (OFDM) technology. speed can be supported.

In 802.11ac, which is a WLAN standard, data may be simultaneously transmitted to multiple users through a multi-user multi-input multi-output (MU-MIMO) technique. However, the WLAN system to which 802.11ac is applied intensively supports one-to-one communication and has a problem in that reception performance is deteriorated in an area where users are dense.

In order to solve this problem, in the WLAN standard 802.11ax (also called HE; High Efficiency), subcarriers available by applying not only MU-MIMO but also Orthogonal Frequency-Division Multiple Access (OFDMA) technology. Multiple access is implemented by dividing and providing to users. Through this, the WLAN system to which 802.11ax is applied can effectively support communication in dense areas and outdoors.

Furthermore, 802.11be (also called EHT; Extremely High Throughput), the next-generation WLAN standard, supports 6GHz unlicensed frequency band, utilizes bandwidth of up to 320MHz per channel, introduces HARQ (Hybrid Automatic Repeat and reQuest), supports up to 16X16 MIMO, etc. do. Through this, the next-generation WLAN system is expected to effectively support low latency and high-speed transmission like NR (New Radio), a 5G technology.

An object of the technical spirit of the present disclosure is to provide an apparatus and method for supporting efficient channel state information feedback of a user in a WLAN system.

In order to achieve the above object, in the baseband circuit provided in the transmitting apparatus of a wireless local area network (WLAN) system according to an aspect of the technical idea of the present disclosure, the storage unit, write data to the storage unit (write data) ) A signal processing unit that is controlled by a read control unit and a control unit, and generates a Physical Layer Convergence Protocol (PLCP) protocol data unit (PPDU) including a preamble and a payload; The data field of the load includes a Null Data Packet Announcement (NDPA) frame, and the NDPA frame includes a MAC header (Medium Access Control Header) and a frame body, and the frame body is a receiving device to receive a PPDU from a transmitting device. It includes a first user information field applied to a device, wherein the first user information field includes a partial bandwidth information subfield including subcarrier index information corresponding to a partial bandwidth designated as a channel feedback section of the receiving device, and reception outside the partial bandwidth It includes an additional partial bandwidth presence subfield indicating whether there is an additional partial bandwidth designated as the channel feedback interval of the device.

In addition, in the baseband circuit provided in the transmission apparatus of a wireless local area network (WLAN) system according to another aspect of the technical concept of the present disclosure, a storage unit, a control unit for writing or reading data to the storage unit, and a control unit Controlled by and including a signal processing unit for generating a PPDU (Physical Layer Convergence Protocol (PLCP) protocol data unit) including a preamble and a payload, wherein the data field of the payload is NDPA (Null Data Packet Announcement) frame, the NDPA frame includes a MAC header (Medium Access Control Header) and a frame body, and the frame body includes a user information field applied to a receiving device to receive a PPDU from a transmitting device. The user information field includes an RU allocation subfield including index information of a resource unit (RU) designated as a channel feedback period of the receiving device.

In addition, in the baseband circuit provided in the receiving apparatus of a wireless local area network (WLAN) system according to another aspect of the technical concept of the present disclosure, a storage unit, a control unit for writing or reading data to the storage unit, and Controlled by the control unit, including a signal processing unit for decoding a PPDU (Physical Layer Convergence Protocol (PLCP) protocol data unit) received from the transmitting device, wherein the PPDU includes a preamble and a payload, The data field of the payload includes a Null Data Packet Announcement (NDPA) frame, the NDPA frame includes a MAC header (Medium Access Control Header) and a frame body, and the frame body includes a first applied to a receiving device. a user information field, wherein the first user information field includes a partial bandwidth information subfield including subcarrier index information corresponding to a partial bandwidth designated as a channel feedback section of the receiving device, and a channel feedback section of the receiving device other than the partial bandwidth. and an additional partial bandwidth presence subfield indicating whether the specified additional partial bandwidth exists.

In addition, in the baseband circuit provided in the receiving apparatus of a wireless local area network (WLAN) system according to another aspect of the technical concept of the present disclosure, a storage unit, a control unit for writing or reading data to the storage unit, and Controlled by the control unit, including a signal processing unit for decoding a PPDU (Physical Layer Convergence Protocol (PLCP) protocol data unit) received from the transmitting device, wherein the PPDU includes a preamble and a payload, The data field of the payload includes a Null Data Packet Announcement (NDPA) frame, the NDPA frame includes a MAC header (Medium Access Control Header) and a frame body, and the frame body includes a first applied to a receiving device. It includes a user information field, and the first user information field includes an RU allocation subfield including index information of a resource unit (RU) designated as a channel feedback period of the receiving device.

According to the technical idea of the present disclosure, the data transmission rate can be improved by preventing an unnecessary overhead increase in the channel state information feedback process through an apparatus and method for supporting an efficient channel state information feedback of a user in a WLAN system. can

1 is a diagram illustrating a wireless local area network (WLAN) system.
2 is a block diagram illustrating a wireless communication device that transmits or receives a PPDU.
3 is a schematic block diagram of the wireless communication device of FIG. 2 .
4 is a view for explaining a channel sounding process according to an embodiment of the present disclosure.
5 is a diagram for explaining the structure of a Null Data Packet Announcement (NDPA) frame defined in 802.11ax.
6 is a table illustrating an example of a subcarrier index range according to an RU index.
7 is a table for explaining an example of a subcarrier index for each bandwidth according to an RU index.
8A and 8B are diagrams for explaining an example of setting a feedback interval when a partial bandwidth feedback method of the 802.11ax standard is applied in a multi-RU allocation environment.
9 is a view for explaining an example of a user information field in an NDPA frame according to an embodiment of the present disclosure.
10 is a view for explaining another example of a user information field in an NDPA frame according to an embodiment of the present disclosure.
11A and 11B are diagrams for explaining an example of setting a feedback interval when the partial bandwidth feedback scheme shown in FIGS. 9 and 10 is applied in a multi-RU allocation environment.
12 is a view for explaining another example of a user information field in an NDPA frame according to an embodiment of the present disclosure.
13 is a diagram for explaining an example of an RU location according to a value of an RU Allocation subfield.
14 is a table for explaining an example of a subcarrier index according to a value of an RU Allocation subfield in a 20 MHz bandwidth.
15 is a table illustrating an example of a subcarrier index according to a value of an RU Allocation subfield in a 40 MHz bandwidth.
16A and 16B are tables for explaining examples of subcarrier indexes according to values of the RU Allocation subfield in an 80 MHz bandwidth.
17A and 17B are diagrams for explaining an example of setting a feedback interval when the partial bandwidth feedback method shown in FIG. 12 is applied in a multi-RU allocation environment.
18 is a diagram for explaining an example of a MIMO control field in a compressed beamforming frame according to an embodiment of the present disclosure.
19 is a diagram illustrating another example of a MIMO control field in a compressed beamforming frame according to an embodiment of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

Advantages and features of the present disclosure, and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments shown below, but will be implemented in various different forms, and can be used interchangeably, and only the present embodiments are provided so that the description of the present disclosure is complete. In addition, it is provided to completely inform those of ordinary skill in the art to which the present disclosure belongs, the scope of the disclosure, and the scope of the present disclosure is only defined by the scope of the claims. In addition, specific configurations described only in each embodiment of the present disclosure may be used in other embodiments. Like reference numerals refer to like elements throughout.

The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the scope of the present disclosure. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, "comprises" and/or "comprising" refers to the presence of one or more other components, steps, operations and/or elements mentioned. or addition is not excluded.

Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used with the meaning commonly understood by those of ordinary skill in the art to which this disclosure belongs. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless clearly defined in particular.

In addition, in describing the embodiments of the present disclosure in detail, OFDM or OFDMA-based wireless communication systems, in particular, IEEE 802.11 standards will be mainly targeted, but the main subject matter of the present disclosure may be other materials having a similar technical background and channel type. of a communication system (eg, long term evolution (LTE), LTE-Advanced (LTE-A), New Radio (NR), Wireless Broadband (WiBro), Global System for Mobile Communication (GSM), such as cellular (cellular) Communication systems or short-distance communication systems such as Bluetooth and NFC (Near Field Communication) can be applied with slight modifications within a range that does not significantly depart from the scope of the present disclosure, which is a technical skill skilled in the art of the present disclosure. It will be possible with the judgment of those with knowledge.

And before proceeding with the detailed description that follows, it is desirable to set forth definitions of certain words and phrases used throughout this patent document. The word "connects" and its derivatives refer to any direct or indirect communication between two or more components, whether or not they are in physical contact with each other. The terms "transmit", "receive", and "communicate", as well as their derivatives, include both direct and indirect communication. The terms “comprise” and “comprises” and their derivatives mean inclusive without limitation. The word "or" is an inclusive word meaning 'and/or'. "Relates to" and its derivatives include, is included in, interconnects with, implies, is implied in, connects to, connects to, binds to, communicates with can, cooperate with, intervene, juxtapose, approximate to, be bound by, have, have the characteristics of, have a relationship with, etc. The term "controller" means any device, system, or part thereof that controls at least one operation. Such a controller may be implemented in hardware or a combination of hardware and software and/or firmware. Functions associated with any particular controller may be centralized or distributed, either locally or remotely. The phrase "at least one" when used with a list of items means that different combinations of one or more of the listed items may be used, and that only one item in the list may be required. For example, “at least one of A, B, and C” includes any one of combinations of A, B, C, A and B, A and C, B and C, and A and B and C.

In addition, various functions described below may be implemented or supported by artificial intelligence technology or one or more computer programs, each of which is composed of computer readable program code and implemented in a computer readable medium. do. The terms "application" and "program" refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or portions thereof suitable for implementation of suitable computer readable program code. The term "computer readable program code" includes computer code of any type, including source code, object code, and executable code. The term "computer-readable medium" means a computer, such as read only memory (ROM), random access memory (RAM), hard disk drive, compact disk (CD), digital video disk (DVD), or any other type of memory. It includes all types of media that can be accessed by “Non-transitory” computer-readable media excludes wired, wireless, optical, or other communication links that transmit transitory electrical or other signals. Non-transitory computer-readable media includes media in which data can be permanently stored, and media in which data can be stored and later overwritten, such as a rewritable optical disk or a removable memory device.

In various embodiments of the present disclosure described below, a hardware approach is described as an example. However, since various embodiments of the present disclosure include technology using both hardware and software, the various embodiments of the present disclosure do not exclude a software-based approach.

Also, terms that refer to control information, terms that refer to entries, terms that refer to network entities, terms that refer to messages, and terms that refer to components of devices used in the description to be described below are It is illustrated for convenience of description. Accordingly, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

1 is a diagram illustrating a wireless local area network (WLAN) system. 2 is a block diagram illustrating a wireless communication device that transmits or receives a PPDU. 3 is a schematic block diagram of the wireless communication device of FIG. 2 .

First, as shown in FIG. 1 , the WLAN system 100 may include APs 101 and 103 (Access Points).

Specifically, the APs 101 and 103 may communicate with at least one network 130 such as the Internet, an Internet protocol (IP) network, or another data network.

In addition, the APs 101 and 103 may provide wireless access to the network 130 for a plurality of STAs 111 to 114 within the coverage areas 120 and 125 of the APs 101 and 103 . Also, the APs 101 and 103 may communicate with each other using wireless fidelity (WiFi) or other WLAN communication technologies. In addition, the APs 101 and 103 may communicate with the plurality of STAs 111 to 114 using wireless fidelity (WiFi) or other WLAN communication technologies.

For reference, depending on the network type, other well-known terms such as "router" and "gateway" may be used instead of "AP" or "access point". Also, in a WLAN, an AP is provided for a radio channel. And, AP may mean STA.

Also, depending on the network type, "STA" or "station" may be "mobile station", "subscriber station", "remote terminal", "user equipment", may be used in place of other well-known terms such as “wireless terminal,” “user device,” or “user.” For convenience, the term “STA” is used herein to denote a remote wireless device that wirelessly accesses an AP or accesses a wireless channel within a WLAN. Although in this document a STA is considered a mobile device (eg, a mobile phone or smartphone), a STA may be a fixed device (eg, a desktop computer, AP, media player, fixed sensor, television, etc.).

The dashed lines show the approximate extent of the coverage areas 120 , 125 . Here, coverage areas 120 and 125 are shown as generally circular for purposes of illustration and illustration. However, the coverage areas 120 and 125 associated with the APs 101 and 103 have a different shape reflecting various changes in the wireless environment related to natural or man-made obstructions, or Depending on the settings, it may have other shapes, including irregular shapes.

As will be described later in detail, the APs 101 and 103 include circuitry and/or a program for UL MU (Uplink Multi-User) or DL MU (Downlink Multi-User) transmission management in the WLAN system. can do.

And Figure 1 shows an example of the WLAN system 100, the embodiment of the present disclosure is not limited thereto. That is, various changes may be made in FIG. 1 .

For example, WLAN system 100 may include any number of APs and any number of STAs, any suitably deployed. Also, the AP 101 can communicate directly with any number of STAs. In addition, the AP 101 may provide a wireless broadband connection with the network 130 to the STAs 111 to 114 .

Similarly, the APs 101 and 103 may communicate directly with the network 130 , respectively, and may provide the network 130 with wireless broadband connectivity with the STAs 111 - 114 . Also, the APs 101 and 103 may implement connections with various external networks, such as external telephone networks or data networks.

Next, in FIG. 2 , a wireless communication device for transmitting or receiving a PPDU is illustrated.

For reference, the wireless communication device 200 of FIG. 2 may be included in a transmitting device (eg, AP) or a receiving device (eg, STA). That is, the wireless communication device of FIG. 2 may be included in any one of the APs 101 and 103 and the STAs 111 to 114 shown in FIG. 1 , for example, a computer or a smart phone. , a portable electronic device, a tablet, a wearable device, a sensor used in the Internet of Things (IoT), and the like.

Specifically, the wireless communication device 200 includes an antenna 190; a front-end module 205; a front-end module (FEM)), a radio frequency integrated circuit (RFIC) 210, and a baseband circuit 220; baseband circuit). Also, although not shown in the drawings, the wireless communication device 200 may further include a power modulator for supplying a power supply voltage (eg, a dynamically variable output voltage) to the power amplifier in the RFIC 210 . In addition, the power modulator may be driven in an average power tracking mode or an envelope tracking mode to generate and output a power voltage.

For reference, the front-end module 205 and the RFIC 210 may be implemented in one chip as a single component. In this case, the function of the front-end module 205 and the function of the RFIC 210 to be described later may be implemented together in one chip. However, for convenience of description, in the embodiment of the present disclosure, the front-end module 205 and the RFIC 210 will be described as separate components from each other as an example.

First, the antenna 190 may be connected to the front-end module 205, and transmits a signal received from the front-end module 205 to another wireless communication device (terminal or base station) or receives it from another wireless communication device. signal may be provided to the front-end module 205 . In addition, the front-end module 205 may be connected to the antenna 190 to separate the transmit frequency and the receive frequency. That is, the front-end module 205 may separate the signal received from the RFIC 210 for each frequency band and provide it to the corresponding antenna 190 . Also, the front-end module 205 may provide the signal received from the antenna 190 to the RFIC 210 .

In this way, the antenna 190 may transmit a frequency-separated signal by the front-end module 205 to the outside or provide a signal received from the outside to the front-end module 205 .

For reference, the antenna 190 may include, for example, an array antenna, but is not limited thereto. In addition, one or more antennas 190 may be configured. Accordingly, in some embodiments, the wireless communication device 200 may support a phased array, multiple-input and multiple-output (MIMO), etc. using a plurality of antennas. However, in FIG. 2 , for convenience of explanation, one antenna is illustrated.

In addition, the front-end module 205 may include an antenna tuner (not shown). In addition, an antenna tuner (not shown) may be connected to the antenna 190 to adjust the impedance of the connected antenna 190 .

The RFIC 210 may generate an RF signal by performing frequency up-conversion on a baseband signal (also referred to as a baseband signal) provided from the baseband circuit 220 . In addition, the RFIC 210 may generate a baseband signal by performing frequency down-conversion on the RF signal provided from the front-end module 205 .

Specifically, the RFIC 210 may include a transmit circuit 212 for frequency upconversion, a receive circuit 214 for frequency downconversion, and a local oscillator 216 for frequency downconversion. have.

For reference, although not shown in the drawings, the transmission circuit 212 may include a first analog baseband filter, a first mixer, and a power amplifier. In addition, the reception circuit 214 may include a second analog baseband filter, a second mixer, and a low-noise amplifier.

Here, the first analog baseband filter may filter the baseband signal received from the baseband circuit 220 and provide it to the first mixer. In addition, the first mixer may perform frequency up-conversion for converting a frequency of a baseband signal from a baseband to a high frequency band through the frequency signal provided by the local oscillator 216 . Through such frequency up-conversion, the baseband signal may be provided to the power amplifier as an RF signal, and the power amplifier may power amplify the RF signal and provide it to the front-end module 205 .

In addition, the low noise amplifier may amplify the RF signal received from the front-end module 205 and provide it to the second mixer. In addition, the second mixer may perform frequency down-conversion for converting the frequency of the RF signal from the high frequency band to the base band through the frequency signal provided by the local oscillator 216 . Through such frequency down-conversion, the RF signal may be provided as a baseband signal to the second analog baseband filter, and the second analog baseband filter may filter the baseband signal and provide it to the baseband circuit 220 . .

Meanwhile, the baseband circuit 220 may receive and process the baseband signal from the RFIC 210 , or generate a baseband signal and provide it to the RFIC 210 .

Also, the baseband circuit 220 may include a controller 222 (Controller), a storage 224 (Storage), and a signal processing unit 225 (Signal Processing Unit).

Specifically, the controller 222 may control not only the baseband circuit 220 but also the overall operation of the RFIC 210 . Also, the control unit 222 may write or read data to the storage unit 224 . To this end, the controller 222 may include at least one processor, a microprocessor, or a microcontroller, or may be a part of the processor. More specifically, the controller 222 may include, for example, a central processing unit (CPU), a digital signal processor (DSP), or the like.

The storage unit 224 may store data such as a basic program, an application program, and setting information for the operation of the wireless communication device 200 . For example, the storage unit 224 may store instructions and/or data related to the control unit 222 , the signal processing unit 225 , or the RFIC 210 . Also, the storage unit 224 may store a frame format, a PPDU format, and RU allocation information.

And the storage unit 224 may include various storage media (storage medium). That is, the storage unit 224 may be configured of a volatile memory, a non-volatile memory, or a combination of a volatile memory and a non-volatile memory, for example, a random access memory (RAM); DRAM, PRAM, MRAM, SRAM, etc.), flash memory (NAND flash memory, NOR flash memory, ONE NAND flash memory, etc.), and the like.

Also, the storage 224 may store various processor-executable instructions. In addition, these processor-executable instructions may be executed by the controller 222 .

The signal processing unit 225 may process a baseband signal provided from the RFIC 210 and may process a baseband signal to be provided to the RFIC 210 .

For reference, for convenience of description, the signal processing unit 225 will be mainly described with respect to the components in a receiving path.

Specifically, the signal processing unit 225 may include a demodulator, a reception filter and a cell searcher (RxFilter & Cell searcher), and other components (Others).

First, the demodulator includes a channel estimator, a data deallocation unit, an interference whitener, a symbol detector, a CSI generator (Channel State Information Generator), and a mobility measurement unit. , Automatic Gain Control Unit, Automatic Frequency Control Unit, Symbol Timing Recovery Unit, Delay Spread Estimation Unit, Time Correlator, etc. As it may be included, the function of each configuration may be performed.

Here, the mobility measurement (Mobility Measurement) unit is a unit for measuring the signal quality of a serving cell (Serving Cell) and / or neighboring cells (Neighbor Cell) in order to support mobility, RSSI (Received Signal Strength Indicator) of the cell, RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality), RS (Reference Signal)-SINR (Signal-to-Interference & Noise Ratio), and the like can be measured.

Subsequently, the reception filter and the cell searcher include a reception filter (RxFilter), a cell searcher (Cell searcher), a Fast Fourier Transform (FFT) unit, a Time Duplex-Automatic Gain Control (TD-AGC) unit, and a Time Duplex-Automatic (TD-AFC) unit. Frequency Control) unit and the like.

Here, the reception filter (RxFilter; also referred to as Rx Front End) may perform operations such as sampling, interference cancellation, and amplification on the baseband signal received from the RFIC 210 . In addition, the cell searcher includes a Primary Synchronization Signal (PSS) detector, a Secondary Synchronization Signal (SSS) detector, and the like, and can measure the size and quality of an adjacent cell signal.

Meanwhile, the other components may include a symbol processor, a channel decoder, and other components in a transmitting path.

Here, the symbol processor may perform channel-deinterleaving, demultiplexing, rate-matching, etc. so that the demodulated signal can be decoded for each channel. In addition, the channel decoder may decode the demodulated signal in units of code blocks. In addition, the symbol processor and the channel decoder are HARQ (Hybrid automatic repeat request) processing unit, turbo decoder, CRC checker, Viterbi decoder, turbo encoder ( Turbo Encoder) and the like.

And other transmit path components are TX FIFO (transmit first-in-first-out), encoder, scrambler, interleaver, constellation mapper, IDFT (Inversed Discrete Fourier Transformer) , a guard interval and windowing insertion module, and the like.

As described above, in FIG. 2 , the baseband circuit 220 is illustrated as including a control unit 222 , a storage unit 224 , and a signal processing unit 225 .

However, in the baseband circuit 220 , two or more of the control unit 222 , the storage unit 224 , and the signal processing unit 225 may be integrated into one. In addition, the baseband circuit 220 may further include additional components in addition to the above-described components or may not include some components. Furthermore, the signal processing unit 225 may further include additional components in addition to the above-described components or may not include some components.

However, in the embodiment of the present disclosure, for convenience of description, the baseband circuit 220 including the above-described configuration will be described as an example.

And in some embodiments, the control unit 222 , the storage unit 224 , and the signal processing unit 225 may be included in one device. Of course, in other embodiments, the control unit 222 , the storage unit 224 , and the signal processing unit 225 may be distributed and included in different devices (eg, distributed architecture).

In addition, the RFIC 210 and the baseband circuit 220 may include components well known to those skilled in the art as shown in the figure. And the corresponding parts may be implemented in a manner well known to those skilled in the art, and may be implemented using hardware, firmware, software logic, or a combination thereof.

However, FIG. 2 only shows an example of a wireless communication device, and the embodiment of the present disclosure is not limited thereto. That is, various changes (addition or deletion of parts) may be made in FIG. 2 .

Here, referring to FIG. 3 , an example in which the configuration of the wireless communication apparatus 200 of FIG. 2 is partially changed (ie, simplified) is illustrated.

Specifically, as shown in FIG. 3, the wireless communication device 200 of FIG. 2 includes a processor 250, a transceiver 260, a memory 270, and an antenna 280. can be configured to

The processor 250 may control overall operations of the transceiver 260 , and may write or read data to the memory 270 . That is, the processor 250 may have, for example, a configuration including the function of the controller 222 of FIG. 2 .

The transceiver 260 may transmit and receive wireless signals and may be controlled by the processor 250 . That is, the transceiver 260 may have, for example, a configuration including the functions of the front-end module 205 , the RFIC 210 , and the signal processing unit 225 of FIG. 2 .

Accordingly, when the wireless communication device 200 is included in the transmitting device, the transceiver 260 transmits a Physical Layer Convergence Protocol (PLCP) protocol data unit (PPDU) including a preamble and a payload. and may transmit the generated PPDU to the receiving device.

On the other hand, when the wireless communication device 200 is included in the receiving device, the transceiver 260 may receive the PPDU including the preamble and the payload from the transmitting device. In addition, the transceiver 260 may decode the payload based on the preamble of the received PPDU. That is, the transceiver 260 may decode the preamble of the PPDU through an internal decoder (eg, the decoder of the signal processing unit 225 of FIG. 2 ), and decode the payload of the PPDU based on the decoding result.

The memory 270 may store data such as a basic program, an application program, and setting information for the operation of the wireless communication device 200 . Accordingly, the memory 270 may store instructions and/or data related to the processor 250 and the transceiver 260 . That is, the memory 270 may have, for example, a configuration including the function of the storage unit 224 of FIG. 2 .

The antenna 280 may be connected to the transceiver 260 , and transmit a signal received from the transceiver 260 to another wireless communication device (terminal or base station), or transmit a signal received from another wireless communication device to the transceiver 260 . can provide That is, the antenna 280 may have, for example, a configuration including the function of the antenna 190 of FIG. 2 .

As such, in the embodiment of the present disclosure, the wireless communication device 200 has the above-described characteristics and configuration. Hereinafter, with reference to FIGS. 4 to 7 , the HE used in the channel sounding process and IEEE 802.11ax An NDPA frame (High Efficiency Null Data Packet Announcement Frame) will be described. Furthermore, an example of setting a feedback interval when the partial bandwidth feedback method of the 802.11ax standard is applied in a multi-RU allocation environment will also be described with reference to FIGS. 8A and 8B .

4 is a view for explaining a channel sounding process according to an embodiment of the present disclosure. 5 is a diagram for explaining the structure of a Null Data Packet Announcement (NDPA) frame defined in 802.11ax. 6 is a table illustrating an example of a subcarrier index range according to an RU index. 7 is a table for explaining an example of a subcarrier index for each bandwidth according to an RU index. 8A and 8B are diagrams for explaining an example of setting a feedback interval when a partial bandwidth feedback method of the 802.11ax standard is applied in a multi-RU allocation environment.

First, referring to FIG. 4 , based on a sounding protocol, a Beamformer (ie, a transmitter (eg, AP)) and a Beamformee (ie, a reception device (eg, a non-AP STA))) A process of feeding back channel state information between the two is shown. Of course, a non-AP STA may also be a beamformer, but for convenience of description, in an embodiment of the present disclosure, a case in which the AP is a beamformer will be described as an example.

For reference, the sounding protocol may refer to a procedure for the Beamformer to receive channel state information as feedback from the Beamformee. In addition, the frame or PPDU described in FIG. 4 (eg, HE NDPA, HE sounding NDP, BFRP Trigger, HE Compressed Beamforming/CQI 1 to n, n is a natural number greater than or equal to 1) may have a structure according to the IEEE 802.11ax standard. have.

Specifically, the channel state information sounding method between the HE Beamformer and the HE Beamformee based on the sounding protocol may be performed in the following order.

(1) In order to obtain channel state information for a downlink channel (for reference, downlink means a beamformee-direction link in Beamformer), first, HE Beamformer informs transmission of HE sounding Null Data Packet (NDP) (or A HE Null Data Packet Announcement (HE NDPA) frame initiating a sounding protocol may be transmitted to HE Beamformees (HE Beamformee 1 to HE Beamformee n, n is a natural number equal to or greater than 1).

The HE NDPA frame may be a control frame used to inform that a channel sounding operation is started and HE sounding NDP is scheduled to be transmitted. That is, since the HE Beamformer transmits the HE NDPA frame before transmitting the HE sounding NDP, the HE Beamformee may prepare to feed back channel state information before receiving the HE sounding NDP.

For reference, the HE NDPA frame may include AID (association identifier) information, feedback type information, etc. of a HE Beamformee that is a transmission target of the HE sounding NDP. That is, the HE NDPA frame may include sounding indication information regarding which STA (ie, HE Beamformee) will measure which downlink channel and in what manner.

The HE Beamformees (ie, HE Beamformees 1 to n) that have received the HE NDPA frame are AID12 subfields included in the STA information field of the HE NDPA frame (hereinafter, to be used interchangeably with the term STA Info field or user information field) It is possible to check the value and determine whether the STA is a sounding target STA.

Also, HE Beamformees can know their feedback order through the order of the STA Info field included in the HE NDPA frame.

(2) After transmitting the HE NDPA frame, the HE Beamformer may transmit the HE sounding NDP after a Short Interframe Space (SIFS) time. For reference, the HE sounding NDP may have a HE PPDU structure in which the data field is omitted.

That is, the HE Beamformer may transmit the HE sounding NDP indicating information on the target downlink channel to be measured by each STA (ie, the HE Beamformee) to the HE beamformees.

This HE sounding NDP may include HE-STF/LTF, and HE-STF (Short Training Field)/LTF (Long Training Field) provides information on the target downlink channel that each STA (ie, HE Beamformee) needs to measure. may include

(3) After the SIFS time after the HE Beamformer transmits the HE sounding NDP, the HE beamformer sends a BFRP Trigger frame that triggers the uplink (for reference, the uplink means the beamformer direction link in the Beamformee) transmission of the HE beamformees. It can be transmitted to beamformees.

The BFRP Trigger frame may include allocation information on uplink resources allocated to each STA (ie, HE Beamformees) in order to feedback-transmit the channel state information of the downlink channel to the uplink.

(4) HE Beamformees that have received the BFRP Trigger frame may acquire downlink channel state information based on the HE NDPA frame, HE sounding NDP, and BFRP Trigger frame, and generate feedback information to be transmitted to the HE Beamformer.

That is, each HE beamformee may generate a HE compressed beamforming frame including feedback information (HE Compressed Beamforming/Channel Quality Indicator (CQI) 1 to n, where n is a natural number equal to or greater than 1) and feedback-transmit it to the HE Beamformer.

Here, the HE Compressed Beamforming / CQI frame may include information about an SNR value for a space-time stream, a compressed beamforming feedback matrix for a subcarrier, and the like. .

As described above, the channel state information sounding method is performed between the HE Beamformer and the HE Beamformee based on the sounding protocol. Hereinafter, the NDPA frame used in the channel sounding procedure described above will be described.

Referring to FIG. 5 , the HE NDPA frame may include a MAC header (Medium Access Control header), a frame body, and a Frame Check Sequence (FCS; consisting of 4 octets or more) fields. Here, the MAC header includes a frame control field (Frame Control; composed of 2 octets), a Duration field (consisting of 2 octets), an RA field (Receiver Address; composed of 6 octets), and a TA field (Transmitter). Address; consists of 6 octets). In addition, the frame body includes a sounding dialog token field (Sounding Dialog Token; composed of 1 octet), and at least one STA information field (STA Info 1 to n; each STA information field is composed of 4 octets, n is 1 or more natural numbers). Of course, each field of the HE NDPA frame may be partially omitted, and other fields may be added. Also, the length of each field may be changed differently from that shown in the drawing.

Briefly explaining each field of the HE NDPA frame, the frame control field (Frame Control) includes information about the version of the MAC protocol and other additional control information, and the duration field (Duration) is NAV (Network Allocation) Vector) for setting time information or information about an identifier (eg, AID; Association ID) of a terminal. In addition, the RA field may include address information of a receiving device (eg, STA or HE beamformee) of the corresponding HE NDPA frame. In addition, the TA field may include address information of a device (eg, AP or HE Beamformer) that transmits the corresponding HE NDPA frame. Also, the sounding dialog token field may be called a sounding sequence field, and the sounding dialog token number subfield in the sounding dialog token field is It may include a value selected by the HE Beamformer to identify the HE NDPA frame.

In addition, the HE NDPA frame may include STA information fields (STA Info 1 to n) corresponding to the number of receiving devices (eg, STAs or HE Beamformees) that receive the HE NDPA frame. That is, the HE NDPA frame may include STA information fields (STA Info 1 to n) including information on sounding target STAs.

More specifically, the STA information field (eg, STA Info 1) includes an 'AID11' subfield, a 'Partial BW Info' subfield, a 'Feedback Type and Ng' subfield, a 'Disambiguation' subfield, and a 'Codebook Size' The subfield may include a 'Nc' subfield, and each subfield may be a subfield defined in the 802.11ax standard. Of course, each subfield of the STA information field may be partially omitted, and another subfield may be added. In addition, the length of each sub-field may be changed differently from that shown.

For reference, in the case of the 'Partial BW Info' subfield (ie, partial bandwidth information subfield), information about the channel that the AP (or HE Beamformer) requests to measure the status of the STA (or HE Beamformee) (ie, partial bandwidth information) may include Specifically, the 'Partial BW Info' subfield may include 'RU Start Index' indicating the first subcarrier index information of the measurement target channel and 'RU End Index' indicating the last subcarrier index information of the measurement target channel. have. In addition, each of the 'RU Start Index' and the 'RU End Index' may consist of 7 bits.

Here, referring to FIG. 6 , when the total bandwidth is 20 MHz, an example of an RU index and a subcarrier range according to a resource unit (RU) type is illustrated.

Furthermore, referring to FIG. 7 , examples of 'RU Start Index ('S')' and 'RU End Index ('E')' for each bandwidth according to the RU Index when 'Ng = 16' are shown. .

That is, each STA (or HE Beamformees) is a channel corresponding to subcarriers between the subcarrier index ranges mapped to the 'RU Start Index' and the 'RU End Index' based on the tables of FIGS. 6 and 7 above. By measuring the state information, it can be fed back to the AP (or HE Beamformer).

Here, the channel state information may include information on the phase and magnitude of the estimated channel frequency response and information on the average signal-to-noise ratio (SNR) of the corresponding channel frequency band.

In summary, the transmitting device (eg, AP or HE Beamformer) has a different 'Partial BW Info' subfield index (ie, different 'RU Start') for each receiving device (eg, STA or HE Beamformee). Index' and/or 'RU End Index') may be specified. Accordingly, the transmitting device (eg, AP or HE Beamformer) may request channel state information for different partial bandwidths for each receiving device (eg, STA or HE Beamformee). In addition, the transmitting device (eg, AP or HE Beamformer) allocates a resource unit (RU) using the channel state information received from each receiving device (eg, STA or HE Beamformee), and performs a Modulation and Coding Scheme (MCS). Selection, determination of the number of space-time streams allocated, and the like may be performed.

In this way, the HE NDPA frame of the 802.11ax standard may be configured. However, as shown in FIGS. 8A and 8B , the RU that the receiving device (eg, STA or HE Beamformee) should measure (that is, the RU corresponding to the channel feedback section of the receiving device set by the transmitting device) as In a state where multiple RUs are designated, using the partial bandwidth feedback method of the 802.11ax standard, the transmitting device (eg, AP or HE Beamformer) sets the channel feedback interval (ie, the channel state information feedback interval) of the corresponding receiving device In this case, an overhead in the channel state information feedback process may increase. Here, RU may mean a downlink resource.

For reference, in FIGS. 8A and 8B , 484+2X996 multiple RUs are designated as RUs to be measured by the first receiving device (STA #1), and 484 as RUs to be measured by the second receiving device (STA #2). A case in which a single RU is designated will be described as an example.

Specifically, for example, when the transmitting device sets the channel feedback period of each receiving device based on the partial bandwidth feedback method of the 802.11ax standard, the 'RU Start Index, RU End Index of the first receiving device (STA #1) ' becomes '0, 111', and 'RU Start Index, RU End Index' of the second receiving device (STA #2) becomes '18, 35'.

Therefore, in the case of the first receiving device (STA #1), even though the second 484 RU is an RU designated as the channel feedback period of the second receiving device (STA #2), the transmission device up to the channel state information corresponding to the second 484 RU will be fed back with That is, the first receiving device (STA #1) feeds back to the transmitting device up to unspecified channel state information as its own channel feedback period, so unnecessary overhead may increase in the channel state information feedback process.

For reference, the above-described unnecessary overhead increase situation may occur in both cases in which RUs for a downlink channel for each receiving device are pre-allocated and in cases in which they are not pre-allocated.

Specifically, when the RU for the downlink channel for each receiving device is pre-allocated, the transmitting device may set the RU for the downlink channel for each receiving device that is pre-allocated as a channel feedback period of each receiving device. On the other hand, if the RU for the downlink channel for each receiving device is not allocated in advance, the transmitting device may set the channel feedback period of each receiving device arbitrarily, and may request feedback for the entire bandwidth channel from each receiving device. have. For reference, the reason that the channel state information feedback process is performed in a state in which RUs for a downlink channel for each receiving device are not allocated in advance may be to obtain channel state information for RU allocation for an initial downlink channel. .

In summary, unnecessary overhead may increase in both the channel state information feedback process in each of the two situations. In addition, both of the above two situations may be situations applicable to the embodiments of the present disclosure. Hereinafter, the description will be made on the premise of these situations when describing the embodiments of the present disclosure.

On the other hand, in the 802.11be standard, a bandwidth of 320 MHz and 16 space-time streams are supported. Compared to the 802.11ax standard, a feedback target (ie, the bandwidth or the number of space-time streams) increases, and thus overhead in the channel state information feedback process. can also increase.

To solve this problem, in an embodiment of the present disclosure, an NDPA frame that can be applied to a next-generation standard (eg, EHT standard) to reduce overhead in a channel state information feedback process may be implemented.

For reference, although not shown in the drawings, the following common improvements may be applied to an NDPA frame (ie, an Extremely High Throughput (EHT) NDPA frame of the 802.11be standard) according to an embodiment of the present disclosure.

First, the Sounding Dialog Token field of the EHT NDPA frame may be composed of 1 byte (ie, 8 bits), of which 2 bits are used to determine which standard the NDPA frame is. It can indicate whether it is an NDPA frame. For example, '00' indicates that the NDPA frame is a VHT (Very High Throughput) NDPA or EHT NPDA frame, and '01' indicates that the corresponding NPDA frame is a HE NDPA or EHT NDPA frame, and '11' In the case of , it may indicate that the corresponding NPDA frame is an EHT NDPA frame.

In addition, 'RU Start Index' and 'RU End Index' in the 'Partial BW Info' subfield of the EHT NDPA frame consists of 8 bits each to express, for example, a maximum bandwidth of 320MHz (in this case, the 'Partial BW Info' subfield field may be composed of 16 bits). Accordingly, the 'RU Start Index' and the 'RU End Index' may have, for example, any one of indices from 0 to 255. Of course, the 'RU Start Index' and the 'RU End Index' may each consist of bits smaller than 8 bits (eg, 4 bits, 6 bits, or 7 bits).

And the 'Nc' subfield of the EHT NDPA frame may be composed of 4 bits to support 16 space-time streams.

In addition, in order to prevent STAs for VHT from erroneously identifying AID (association identifier) in HE NDPA or EHT NDPA, the 'Disambiguation' subfield of the EHT NDPA frame is set to a specific position (ie, B(16*n+11) for A natural number equal to or greater than n=1; for example, it may be inserted every B(27), B(43), B(59),??). In this case, the 'Disambiguation' subfield may consist of 1 bit, and the value of the 'Disambiguation' subfield may be '1'.

As such, the above-described common improvements can be applied to the NDPA frame (ie, an Extremely High Throughput (EHT) NDPA frame for the 802.11be standard) according to an embodiment of the present disclosure. With reference, various examples of a user information field (ie, an STA information field (STA Info field)) in an NDPA frame according to an embodiment of the present disclosure will be described in detail.

9 is a view for explaining an example of a user information field in an NDPA frame according to an embodiment of the present disclosure. 10 is a view for explaining another example of a user information field in an NDPA frame according to an embodiment of the present disclosure. 11A and 11B are diagrams for explaining an example of setting a feedback interval when the partial bandwidth feedback scheme shown in FIGS. 9 and 10 is applied in a multi-RU allocation environment. 12 is a diagram for explaining another example of a user information field in an NDPA frame according to an embodiment of the present disclosure. 13 is a diagram for explaining an example of an RU location according to a value of an RU Allocation subfield. 14 is a table for explaining an example of a subcarrier index according to a value of an RU Allocation subfield in a 20 MHz bandwidth. 15 is a table illustrating an example of a subcarrier index according to a value of an RU Allocation subfield in a 40 MHz bandwidth. 16A and 16B are tables for explaining examples of subcarrier indexes according to values of the RU Allocation subfield in an 80 MHz bandwidth. 17A and 17B are diagrams for explaining an example of setting a feedback interval when the partial bandwidth feedback method shown in FIG. 12 is applied in a multi-RU allocation environment.

For reference, the NDPA frame described in FIGS. 9 to 17B may be generated by the wireless communication device 200 (when the wireless communication device is an AP) illustrated in FIGS. 2 and 3 , and shown in FIGS. 2 and 3 . It may be decoded in the wireless communication device 200 (when the wireless communication device is an STA).

First, referring to FIG. 9 , an example of a user information field (ie, an STA Info field) in an NDPA frame according to an embodiment of the present disclosure is illustrated.

In the case of FIG. 9 , it is a case regarding an NDPA frame in which two or more STA Info fields can be set for one receiving device (eg, STA or HE Beamformee) to which multiple RUs are designated as a channel feedback period. That is, a plurality of partial bandwidths as a channel feedback period for one receiving device (two or more partial bandwidths, each partial bandwidth may consist of one RU or a set of a plurality of adjacent RUs; yes; For example, if two 996 RUs of FIG. 8A constitute one partial bandwidth), the NDPA frame of FIG. 9 includes a plurality of STA Info fields indicating subcarrier indexes corresponding to respective partial bandwidths (eg, 2 more than one STA Info field). However, for convenience of description, in the embodiment of the present disclosure, NDPA sets 'two STA Info fields' for one receiving device (eg, STA or HE Beamformee) to which multiple RUs are designated as a channel feedback period. A frame will be described as an example.

For reference, the plurality of STA Info fields may include different 'Partial BW Info' subfields, and indexes of each identifier subfield ('AID11' subfield) may be the same. In addition, the 'Partial BW Info' subfield of each STA Info field includes 'first subcarrier index information' and 'last subcarrier index information' corresponding to each partial bandwidth (for reference, each partial bandwidth is not adjacent to each other). , respectively, and detailed contents thereof will be described below.

Specifically, the NDPA frame of FIG. 9 may be included in a payload (more specifically, a data field of the payload) of the PPDU. The NDPA frame may include a MAC header, a frame body, and an FCS field.

In particular, the frame body includes a sounding dialog token field and at least one STA information field (STA Info 1 to n, n is a natural number greater than or equal to 1, the STA information field can also be expressed as a user information field) may include

Specifically, for example, the first STA information field (STA Info 1) among the at least one STA information field (STA Info 1 to n) includes an NDPA frame from a transmitting device (eg, AP or HE Beamformer). It may be applied to a receiving device (eg, STA or HE Beamformee) to receive the PPDU. Accordingly, the first STA information field (STA Info 1) may include STA-specific control information applied to the corresponding receiving device.

Here, the first STA information field (STA Info 1) includes the 'AID11' subfield, the 'Feedback Type and Ng' subfield, the 'Disambiguation' subfield, the 'Codebook Size' subfield, and the 'Nc' subfield in addition to the 'Partial' subfield. It may further include a 'BW Info #1' subfield, a 'Partial BW Info #2 Present' subfield, and a 'Reserved' subfield.

Some of the 'AID11' subfield, 'Feedback Type and Ng' subfield, 'Disambiguation' subfield, 'Codebook Size' subfield, 'Nc' subfield, and 'Reserved' subfield are the characteristics of the aforementioned EHT NDPA frame may be configured according to , and the remaining part may be configured according to the characteristics of the above-described HE NDPA frame. For reference, in the case of a subfield in which 'TBD' is written instead of the number of bits in the drawing (eg, 'Feedback Type and Ng' subfield), in the embodiment of the present disclosure, the number of bits can be changed. That is, in the case of subfields in which 'TBD' is written, the number of bits is not fixed and can be changed. Of course, even when the number of bits is described in the drawing, the number of bits may be changed. However, for convenience of explanation, in the embodiment of the present disclosure, in the case of subfields in which 'TBD' is written, the number of bits can be changed, and in the case of subfields in which 'number of bits' is written, the number of bits is configured will be described with an example.

The 'Partial BW Info #1' subfield, for example, may consist of 16 bits (of course, it may consist of the number of bits less than 16 bits), and corresponds to a partial bandwidth designated as a channel feedback period of the corresponding receiving device. It may be a partial bandwidth information subfield including subcarrier index information. In addition, the 'Partial BW Info #2 Present' subfield may consist of 1 bit, and is an additional partial bandwidth presence subfield indicating whether an additional partial bandwidth designated as a channel feedback period of the corresponding receiving device other than the partial bandwidth exists. can

That is, in the NDPA frame of FIG. 9, unlike the HE NDPA frame, a 'Partial BW Info #2 Present' subfield may be newly added, and the transmitting device transmits the corresponding receiving device through the 'Partial BW Info #2 Present' subfield. It is possible to express whether there is an additional partial bandwidth designated as a channel feedback period of .

Specifically, when there is an additional partial bandwidth designated as the channel feedback section of the corresponding receiving device, the value of the 'Partial BW Info #2 Present' subfield may be '1', and the additional partial bandwidth designated as the channel feedback section of the corresponding receiving device is added. When the partial bandwidth does not exist, the value of the 'Partial BW Info #2 Present' subfield may be '0'.

Furthermore, when there is an additional partial bandwidth designated as a channel feedback section of the corresponding receiving device (that is, when the value of the 'Partial BW Info #2 Present' subfield is '1'), the frame body is applied to the corresponding receiving device. A second STA information field (STA Info 2) may be further included as the STA information field.

Here, the second STA information field (STA Info 2) includes a partial bandwidth information subfield ('Partial BW Info #2' subfield) including subcarrier index information corresponding to the additional partial bandwidth, and the additional partial bandwidth corresponding to the subfield ('Partial BW Info #2' subfield). It may include an additional partial bandwidth presence subfield ('Partial BW Info #2 Present' subfield) indicating that it is designated as a channel feedback period of the receiving device. Furthermore, the identifier subfield ('AID11' subfield) of the second STA information field (STA Info 2) has the same index as the identifier subfield ('AID11' subfield) of the first STA information field (STA Info 1). can

For reference, as shown in FIG. 9 , when there are two partial bandwidths targeted for multi-RU (ie, when the number of STA Info fields is two), additional partial bandwidths are added to the second STA information field (STA Info 2). The presence subfield ('Partial BW Info #2 Present' subfield) may not be included. And in this case, the 'Reserved' subfield may be included in the second STA information field (STA Info 2) instead of the additional partial bandwidth presence subfield ('Partial BW Info #2 Present' subfield).

Furthermore, unlike shown in FIG. 9 , when the partial bandwidth to be multi-RU is 3 (ie, when the number of STA Info fields is 2), in the second STA information field (STA Info 2), 'Partial BW An additional partial bandwidth presence subfield ('Partial BW Info #3 Present' subfield) indicating whether an additional partial bandwidth (Partial BW #3) exists other than the Info #2 Present' subfield may be included.

However, in the embodiment of the present disclosure, for convenience of description, the second STA information field (STA Info 2) having the structure shown in FIG. 9 will be described as an example.

Meanwhile, the second STA information field (STA Info 2) may exist immediately after the first STA information field (STA Info 1) in the NDPA frame.

And the 'Partial BW Info #1' subfield of the first STA information field (STA Info 1) includes first and last subcarrier index information corresponding to the partial bandwidth, and the second STA information field (STA Info 2) of The 'Partial BW Info #2' subfield may include first and last subcarrier index information corresponding to the additional partial bandwidth.

In addition, the partial bandwidth information subfields ('Partial BW Info #1' subfield and 'Partial BW Info #2' subfield) of the first and second STA information fields (STA Info 1 and 2) are, for example, 16 It may consist of bits (of course, it may consist of a number of bits less than or more than 16 bits). In addition, each of the first and second STA information fields (STA Info 1 and 2), each of the additional partial bandwidth presence subfields ('Partial BW Info #2 Present' subfield) may consist of 1 bit.

On the other hand, when there is no additional partial bandwidth designated as the channel feedback period of the corresponding receiving device, only the first STA information field (STA Info 1) may be included in the frame body as an STA information field applied to the corresponding receiving device. Of course, in this case, the second STA information field (STA Info 2) shown in the figure may be an STA information field applied to another receiving device.

For reference, in the NDPA frame of FIG. 9, each STA Info field may be composed of, for example, 48 bits, and in this case, the 'Disambiguation' subfield according to the 'Disambiguation' subfield insertion method described above in the 27th and 43rd bits. Fields can be inserted. In addition, in order to indicate that the corresponding NDPA frame is an EHT NDPA frame, 2 bits of the Sounding Dialog Token field may be allocated as '00, 01, or 11'. Of course, the number of bits of each STA Info field of FIG. 9 may be configured with a number of bits other than 48 bits. However, in the embodiment of the present disclosure, for convenience of explanation, the number of bits of each STA Info field of FIG. 9 is 48 A bit will be described as an example.

As described above, an example of the user information field in the NDPA frame according to an embodiment of the present disclosure is configured, and the transmitting device sends multiple RUs (multiple RUs composed of a plurality of partial bandwidths) to the designated receiving device as a channel feedback period. In the case of transmitting the NDPA frame shown in 9 , the corresponding receiving device may feedback-transmit only the state information of the channel assigned to it based on the received NDPA frame to the transmitting device. Accordingly, a problem in which unnecessary overhead increases in the channel state information feedback process can be prevented.

Next, referring to FIG. 10 , another example of a user information field (ie, STA Info field) in an NDPA frame according to an embodiment of the present disclosure is illustrated.

In the case of FIG. 10, in relation to one receiving device (eg, STA or HE Beamformee) to which multiple RUs are designated as a channel feedback period, NDPA capable of setting two or more partial bandwidth information subfields in one STA Info field It's a frame case. That is, a plurality of partial bandwidths as a channel feedback period for one receiving device (two or more partial bandwidths, each partial bandwidth may consist of one RU or a set of a plurality of adjacent RUs; yes; For example, if two 996 RUs of FIG. 8A constitute one partial bandwidth), the NDPA frame of FIG. 10 includes subcarrier indexes corresponding to respective partial bandwidths (for reference, each partial bandwidth is not adjacent to each other). A plurality of indicated partial bandwidth information subfields may be included in one STA Info field. Accordingly, in the NDPA frame of FIG. 10, in addition to the 'Partial BW Info' subfield for one partial bandwidth, one or more additional 'Partial BW Info' for one or more additional partial bandwidths that are not adjacent to the one partial bandwidth Since it may further include a subfield, detailed content thereof will be described below. For reference, for convenience of description, in the embodiment of the present disclosure, in relation to one receiving device (eg, STA or HE Beamformee) to which multiple RUs are designated as a channel feedback period, '2' in one STA Info field An NDPA frame setting 'partial bandwidth information subfields' will be described as an example.

Specifically, the NDPA frame of FIG. 10 may be included in a payload (more specifically, a data field of the payload) of the PPDU. The NDPA frame may include a MAC header, a frame body, and an FCS field.

In particular, the frame body may include a sounding dialog token field and at least one STA information field (STA Info 1 to n, where n is a natural number equal to or greater than 1).

Specifically, for example, the first STA information field (STA Info 1) among the at least one STA information field (STA Info 1 to n) includes an NDPA frame from a transmitting device (eg, AP or HE Beamformer). It may be applied to a receiving device (eg, STA or HE Beamformee) to receive the PPDU. Accordingly, the first STA information field (STA Info 1) may include STA-specific control information applied to the corresponding receiving device.

Here, the first STA information field (STA Info 1) includes the 'AID11' subfield, the 'Feedback Type and Ng' subfield, the 'Disambiguation' subfield, the 'Codebook Size' subfield, and the 'Nc' subfield in addition to the 'Partial' subfield. It may further include a 'BW Info #1' subfield, a 'Partial BW Info #2 Present' subfield, and a 'Reserved' subfield. Of course, the first STA information field (STA Info 1) may further include a 'Partial BW Info #2' subfield depending on circumstances, and details thereof will be described later.

Some of the 'AID11' subfield, 'Feedback Type and Ng' subfield, 'Disambiguation' subfield, 'Codebook Size' subfield, 'Nc' subfield, and 'Reserved' subfield are the characteristics of the aforementioned EHT NDPA frame may be configured according to , and the remaining part may be configured according to the characteristics of the above-described HE NDPA frame. In addition, although three 'Reserved' subfields are shown in the drawing, the number of 'Reserved' subfields can be changed (eg, a 'Reserved' subfield may be disposed only in B63). For reference, in the case of a subfield in which 'TBD' is written instead of the number of bits in the drawing (eg, 'Feedback Type and Ng' subfield), in the embodiment of the present disclosure, the number of bits is variable. That is, in the case of the subfields in which 'TBD' is written, the number of bits is not fixed and can be changed, so a detailed description thereof will be omitted.

The 'Partial BW Info #1' subfield may be a partial bandwidth information subfield including subcarrier index information corresponding to a partial bandwidth designated as a channel feedback section of the corresponding receiving device. In addition, the number of bits of the 'Partial BW Info #1' subfield may be 'TBD'. That is, the number of bits of the 'Partial BW Info #1' subfield varies within a range of, for example, 16 bits or less (that is, it can vary between 1 and 16 bits; for example, the number of bits of the subfield is may be 14 bits) or may exceed 16 bits.

For reference, the number of bits of the 'Partial BW Info #1' subfield may be changed depending on which subcarrier unit the 'RU Start Index' and 'RU End Index' of the 'Partial BW Info #1' subfield are set in. have. For example, when the 'RU Start Index' and 'RU End Index' of the 'Partial BW Info #1' subfield are set in units of 26-tone RUs (that is, 26-subcarrier RUs), 52-tone RUs, 106 When configured in units of -tone RUs or 242-tone RUs, the number of bits in the 'Partial BW Info #1' subfield may be reduced. Accordingly, in order to reduce the number of bits of the 'Partial BW Info #1' subfield to 16 bits or less, the 'RU Start Index' and 'RU End Index' of the 'Partial BW Info #1' subfield are 52-tone RU , a 106-tone RU unit, or a 242-tone RU unit may be set as the basis.

In addition, the 'Partial BW Info #2 Present' subfield may consist of 1 bit, and is an additional partial bandwidth presence subfield indicating whether an additional partial bandwidth designated as a channel feedback period of the corresponding receiving device other than the partial bandwidth exists. can

That is, in the NDPA frame of FIG. 10, unlike the HE NDPA frame, a 'Partial BW Info #2 Present' subfield may be newly added, and the transmitting device transmits the corresponding receiving device through the 'Partial BW Info #2 Present' subfield. It is possible to express whether there is an additional partial bandwidth designated as a channel feedback period of .

Specifically, when there is an additional partial bandwidth designated as the channel feedback section of the corresponding receiving device, the value of the 'Partial BW Info #2 Present' subfield may be '1', and the additional partial bandwidth designated as the channel feedback section of the corresponding receiving device is added. When the partial bandwidth does not exist, the value of the 'Partial BW Info #2 Present' subfield may be '0'.

Furthermore, when an additional partial bandwidth designated as a channel feedback section of the corresponding receiving device exists (that is, when the value of the 'Partial BW Info #2 Present' subfield is '1'), the first STA information field (STA Info 1) ) may further include a 'Partial BW Info #2' subfield. On the other hand, when the additional partial bandwidth designated as the channel feedback period of the corresponding receiving device does not exist, only the 'Partial BW Info #1' subfield is included in the first STA information field (STA Info 1) as the partial bandwidth information subfield. can

Here, the 'Partial BW Info #2' subfield may be an additional partial bandwidth information subfield including subcarrier index information corresponding to the additional partial bandwidth designated as a channel feedback period of the corresponding receiving device. And, although the number of bits of the 'Partial BW Info #2' subfield is 'TBD', the range of 16 bits or less (ie, 1 to 16 between bits; for example, 14 bits) or may exceed 16 bits.

For reference, the 'Partial BW Info #2' subfield may be disposed in the first STA information field (STA Info 1) immediately after the 'Partial BW Info #2 Present' subfield. In addition, the 'Partial BW Info #1' subfield includes first and last subcarrier index information corresponding to the partial bandwidth, and the 'Partial BW Info #2' subfield includes the first and last subcarriers corresponding to the additional partial bandwidth. Index information may be included.

Meanwhile, in the NDPA frame of FIG. 10, each STA Info field may consist of, for example, 64 bits. In this case, the 'Disambiguation' subfield is inserted into the 27th, 43rd, and 59th bits according to the 'Disambiguation' subfield insertion method described above. A subfield may be inserted. In addition, in order to indicate that the corresponding NDPA frame is an EHT NDPA frame, 2 bits of the Sounding Dialog Token field may be allocated as '00, 01, or 11'. Of course, the number of bits of each STA Info field of FIG. 10 may be configured with a number of bits other than 64 bits. However, in the embodiment of the present disclosure, for convenience of explanation, the number of bits of each STA Info field of FIG. 10 is 64 A bit will be described as an example.

As described above, another example of the user information field in the NDPA frame according to an embodiment of the present disclosure is configured, and the transmitting device receives multiple RUs (that is, multiple RUs composed of a plurality of partial bandwidths) as a channel feedback period designated by the receiving device. When transmitting the NDPA frame shown in FIG. 10 to the user, the corresponding receiving device may feedback-transmit only the state information of the channel designated to the receiving device based on the received NDPA frame to the transmitting device. Accordingly, a problem in which unnecessary overhead increases in the channel state information feedback process can be prevented.

As such, one example and another example of a user information field in an NDPA frame according to an embodiment of the present disclosure may be configured to support a multi-RU designation situation and 802.11be standard (or a standard after 802.11be).

Accordingly, as shown in FIGS. 11A and 11B , even if multiple RUs are designated as RUs to be measured by a receiving device (eg, STA or HE Beamformee), in FIGS. 9 and 10 , When the transmitting device (eg, AP or HE Beamformer) sets the channel feedback section of the corresponding receiving device based on the partial bandwidth feedback method according to the embodiment, the problem of increasing the overhead in the channel information feedback process is prevented can be

For reference, in FIGS. 11A and 11B , 484+2X996 multiple RUs are designated as RUs that the first receiving device (STA #1) should measure, and 484+2X996 multiple RUs are designated as the RUs that the second receiving device (STA #2) should measure. A case in which a single RU is designated will be described as an example.

Specifically, for example, when the transmitting apparatus sets the channel feedback period of each receiving apparatus based on the partial bandwidth feedback method described above in FIGS. 9 and 10 , the 'RU Start Index of the second receiving apparatus (STA #2)' , RU End Index' becomes '18, 35', and partial bandwidth information of the first receiving device (STA #1) may be divided into two pieces (Partial BW Info #1 and Partial BW Info #2). That is, 'RU Start Index, RU End Index' of the first partial bandwidth of the first receiving device (STA #1) becomes '0, 17', and 'RU' of the second partial bandwidth of the first receiving device (STA #1) Start Index, RU End Index' may be '36, 111'.

Accordingly, in the case of the first receiving device (STA #1), the channel state information of the second 484 RUs (ie, RU indexes 18 to 35) designated as the channel feedback period of the second receiving device (STA #2) is duplicated by the transmitting device It is possible to feed back only the channel state information designated as its own channel feedback period to the transmitting apparatus without being fed back to. That is, since the first receiving device (STA #1) does not feed back unspecified channel state information to the transmitting device as its channel feedback period, it is possible to prevent an unnecessary overhead increase in the channel state information feedback process. .

Meanwhile, referring to FIG. 12 , another example of a user information field (ie, STA Info field) in an NDPA frame according to an embodiment of the present disclosure is illustrated.

In the case of FIG. 12, unlike FIGS. 9 and 10, in the STA Info field for one receiving device (eg, STA or HE Beamformee) to which multiple RUs are designated as a channel feedback period, instead of a partial bandwidth information subfield, an RU allocation subfield This is a case about an NDPA frame with fields added. That is, a plurality of partial bandwidths as a channel feedback period for one receiving device (two or more partial bandwidths, each partial bandwidth may consist of one RU or a set of a plurality of adjacent RUs; yes; For example, if two 996 RUs of FIG. 8A constitute one partial bandwidth), the NDPA frame of FIG. 12 may include an RU allocation subfield indicating a feedback period of the corresponding receiving device in the STA Info field. For reference, the size and location of the RU for which the transmitting device (eg, Beamformer) requested feedback can be identified through the RU Allocation subfield along with bandwidth information, in the following, Let me explain the specifics about this.

Specifically, the NDPA frame of FIG. 12 may be included in a payload (more specifically, a data field of the payload) of the PPDU. The NDPA frame may include a MAC header, a frame body, and an FCS field.

In particular, the frame body may include a sounding dialog token field and at least one STA information field (STA Info 1 to n, where n is a natural number equal to or greater than 1).

Specifically, for example, the first STA information field (STA Info 1) among the at least one STA information field (STA Info 1 to n) includes an NDPA frame from a transmitting device (eg, AP or HE Beamformer). It may be applied to a receiving device (eg, STA or HE Beamformee) to receive the PPDU. Accordingly, the first STA information field (STA Info 1) may include STA-specific control information applied to the corresponding receiving device.

Here, the first STA information field (STA Info 1) includes an 'AID11' subfield, a 'Feedback Type and Ng' subfield, a 'Disambiguation' subfield, a 'Codebook Size' subfield, and an 'Nc' subfield in addition to the 'RU' subfield. It may further include a 'Allocation' subfield and a 'Reserved' subfield.

Some of the 'AID11' subfield, 'Feedback Type and Ng' subfield, 'Disambiguation' subfield, 'Codebook Size' subfield, 'Nc' subfield, and 'Reserved' subfield are the characteristics of the aforementioned EHT NDPA frame may be configured according to , and the remaining part may be configured according to the characteristics of the above-described HE NDPA frame. For reference, in the case of a subfield in which 'TBD' is written instead of the number of bits in the drawing (eg, 'Feedback Type and Ng' subfield), in the embodiment of the present disclosure, the number of bits is variable. That is, in the case of the subfields in which 'TBD' is written, the number of bits is not fixed and can be changed, so a detailed description thereof will be omitted.

The 'RU Allocation' subfield is, for example, a specific number of bits (eg, 9 bits; 2 bits) to which band the STA's channel feedback period belongs to to express a maximum 320 MHz bandwidth according to the 802.11be standard. used, and the remaining 7 bits are used to indicate a single RU or multiple RUs designated as a channel feedback period of the STA), and may include index information of a resource unit (RU) designated as a channel feedback period of the corresponding receiving device. have. And the index information on the RU may indicate the size and location of the RU.

For reference, the channel feedback period of the receiving device among '9 bits (eg, B8 (LSB), B7, B6, B5, B4, B3, B2, B1, B0 (MSB))' of the 'RU Allocation' subfield The '7 bits' used to indicate the RU information designated as have. In this case, for example, the values of the 'RU Allocation' subfield of the trigger frame defined in the 802.11ax (HE) standard as the value of 'B7-B0' of the 'RU Allocation' subfield (8 bits; 'B7') -B0') can be used as it is.

In addition, among the '9 bits' of the 'RU Allocation' subfield, the '7 bits' used to indicate the RU information designated as the channel feedback section of the receiving device are 'B8-B2', and in which band is the channel feedback section of the receiving device? The remaining '2 bits' used to indicate whether it belongs may be 'B1, B0'. In this case, for example, the 'RU Allocation' of the trigger frame defined in the 802.11ax (HE) standard as the value of 'B8-B2, B0' or 'B8-B1' of the 'RU Allocation' subfield. It is possible to use the subfield values (8 bits; the value of 'B7-B0') as they are.

Of course, if a bandwidth of 320 MHz can be expressed, the 'RU Allocation' subfield may be configured with a number of bits other than 9 bits (eg, 10 bits or more or 8 bits or less). For example, when the minimum RU size is set to 242-tone RU rather than 26-tone RU, the 'RU Allocation' subfield may express a bandwidth of 320 MHz with only 7 bits. However, in the embodiment of the present disclosure, for convenience of description, an example in which the 'RU Allocation' subfield consists of 9 bits will be described.

For reference, the receiving device may find subcarrier index information corresponding to the corresponding index information based on the index information of the 'RU Allocation' subfield using a mapping table stored therein. Here, the mapping table may include, for example, the tables of FIGS. 14 to 16 to be described later, but is not limited thereto. In addition, subcarrier index information corresponding to the index information of the 'RU Allocation' subfield (eg, the index of the 'B7-B1 of the RU Allocation subfield' column of FIG. 14) (that is, the RU designated as the channel feedback interval of the receiving device) As 'RU Start Index' and 'RU End Index' corresponding to, for example, indexes of 'RU Index', 'S', 'E' columns of FIG. However, depending on circumstances, it may point to a subcarrier index outside the designated RU range to avoid extra-interpolation.

As such, in the NDPA frame of FIG. 12, unlike the HE NDPA frame, a 'RU Allocation' subfield may be newly added instead of the 'Partial BW Info' subfield, and the transmitting device receives the corresponding reception through the 'RU Allocation' subfield. It is possible to set a section for which the device should give feedback.

Here, referring to FIG. 13 , an example of an RU location according to the value of the 'RU Allocation' subfield is shown. Specifically, an example of the RU location according to the value of the 'RU Allocation' subfield, the RU size, and the RU index is shown.

Furthermore, referring to FIGS. 13 to 16B , examples of subcarrier indexes according to values of the RU Allocation subfield in 20 MHz, 40 MHz, and 80 MHz bandwidths are illustrated. Specifically, examples of RU Start Index ('S')' and 'RU End Index ('E')' according to the value of the RU Allocation subfield for each bandwidth, RU size, and RU index are shown.

For reference, in the tables shown in FIGS. 14 to 16B, '7 bits' (that is, B7-B1) used to indicate RU information designated as a channel feedback period of the receiving device among '9 bits' of the 'RU Allocation' subfield )' is shown, and the remaining '2 bits (B8 (ie, LSB: Least Significant Bit)), B0 (ie, MSB: Most Significant Bit) used to indicate to which band the channel feedback period of the receiving device belongs. ' is not shown.

Although not shown in the drawing, the '2 bits (B8, B0)' used to indicate to which band the channel feedback section of the receiving device belongs may be set, for example, as follows.

- When DL BW=320MHz and the channel feedback section of the receiving device belongs to the primary 160MHz => [B8 B0]=[0 0]

- When DL BW = 320MHz and the channel feedback section of the receiving device belongs to higher 80MHz of secondary 160MHz => [B8 B0]=[1 1]

- When DL BW=240MHz and the channel feedback section of the receiving device belongs to primary 80MHz => [B8 B0]=[x 0] (x is any value of 0 or 1)

- When DL BW=240MHz and the channel feedback section of the receiving device belongs to 160MHz instead of primary 80MHz => [B8 B0]=[0 1]

- When DL BW=160+80MHz and the channel feedback section of the receiving device belongs to higher 80MHz among 160MHz => [B8 B0]=[1 1]

- When DL BW=160MHz and the channel feedback section of the receiving device belongs to the primary 80MHz => [B8 B0]=[x 0] (x is any value 0 or 1)

Of course, the description of the '7 bits (B7-B1)' and the aforementioned '2 bits (B8, B0)' of the 'RU Allocation' subfield shown in FIGS. 14 to 16B is only an example, and FIG. 12 The 'RU Allocation' subfield of 'RU Allocation' is not limited to the table shown in FIGS. 14 to 16B and the above description.

In this way, the receiving device (eg, STA or HE Beamformee) can check the feedback section set to itself based on the 'RU Allocation' subfield in the NDPA frame provided from the transmitting device (eg, AP or HE Beamformer). have. That is, the receiving device may check the information as in the table of FIGS. 13 to 16B described above through the 'RU Allocation' subfield. In addition, the receiving device measures channel state information corresponding to subcarriers between the subcarrier index ranges mapped to the 'RU Start Index' and the 'RU End Index' based on the checked feedback period and feeds back to the AP (or HE Beamformer). can do.

Meanwhile, in the NDPA frame of FIG. 12 , each STA Info field may be composed of, for example, 32 bits. In this case, the 'Disambiguation' subfield is inserted into the 27th bit according to the above-described 'Disambiguation' subfield insertion method. can be In addition, in order to indicate that the corresponding NDPA frame is an EHT NDPA frame, 2 bits of the Sounding Dialog Token field may be allocated as '00, 01, or 11'. Of course, the number of bits of each STA Info field of FIG. 12 may consist of a number of bits other than 32 bits, but in the embodiment of the present disclosure, for convenience of explanation, the number of bits of each STA Info field of FIG. 12 is 32 A bit will be described as an example.

As described above, another example of the user information field in the NDPA frame according to an embodiment of the present disclosure is configured, and the transmitting device receives multiple RUs (ie, multiple RUs composed of a plurality of partial bandwidths) designated as a channel feedback period. When transmitting the NDPA frame shown in FIG. 12 to the device, the corresponding receiving device may feedback-transmit only the state information of the channel designated to it based on the received NDPA frame to the transmitting device. Accordingly, a problem in which unnecessary overhead increases in the channel state information feedback process can be prevented.

As such, another example of the user information field in the NDPA frame according to an embodiment of the present disclosure may be configured to support a multi-RU designation situation and 802.11be standard (+ 802.11be or later standard).

Accordingly, as shown in FIGS. 17A and 17B , even if multiple RUs are designated as RUs to be measured by a receiving device (eg, STA or HE Beamformee), in the embodiment of the present disclosure described above in FIG. 12 , When the transmitting device (eg, AP or HE Beamformer) sets the channel feedback section of the corresponding receiving device based on the partial bandwidth feedback method according to .

For reference, in FIGS. 17A and 17B , 484+2X996 multi-RUs are designated as RUs that the first receiving device (STA #1) should measure, and 484+2X996 multiple RUs are designated as RUs that the second receiving device (STA #2) should measure. A case in which a single RU is designated will be described as an example.

Specifically, for example, when the transmitting device sets the channel feedback period of each receiving device based on the partial bandwidth feedback scheme described above in FIG. 12 , the STA Info field (ie, STA of the second receiving device STA #2) In Info 2), the value (ie, 9 bits) of the 'RU Allocation' subfield in the subfield becomes '001000001', and the 'RU Start Index, RU End Index' corresponding to '001000001' may be '18, 35'. . Also in this case, the value (ie, 9 bits) of the 'RU Allocation' subfield in the STA Info field (ie, STA Info 1) of the first receiving device (STA #1) becomes '001010111', and in '001010111' The corresponding 'RU Start Index, RU End Index' may be '0, 17' and '36, 111'.

Accordingly, in the case of the first receiving device (STA #1), the channel state information of the second 484 RUs (ie, RU indexes 18 to 35) designated as the channel feedback period of the second receiving device (STA #2) is duplicated by the transmitting device It is possible to feed back only the channel state information designated as its own channel feedback period to the transmitting apparatus without being fed back to. That is, the first receiving device (STA #1) does not feed back unassigned channel state information to the transmitting device as its channel feedback period, thereby preventing an unnecessary overhead increase in the channel state information feedback process. have.

As described above, various examples of the user information field (that is, the STA information field (STA Info field)) in the NDPA frame according to the embodiment of the present disclosure are implemented. Hereinafter, with reference to FIGS. 18 and 19, Various examples of a MIMO control field (ie, a MIMO control field) in a compressed beamforming/Channel Quality Indicator (CQI) according to an embodiment of the present disclosure will be described in detail.

18 is a diagram for explaining an example of a MIMO control field in a compressed beamforming frame according to an embodiment of the present disclosure. 19 is a diagram for explaining another example of a MIMO control field in a compressed beamforming frame according to an embodiment of the present disclosure.

For reference, the compressed beamforming frame described in FIGS. 18 and 19 may be generated by the wireless communication device 200 (when the wireless communication device is an STA) shown in FIGS. 2 and 3, and in FIGS. 2 and 3 It may be decoded in the illustrated wireless communication device 200 (when the wireless communication device is an AP). In addition, the compressed beamforming frame may be a frame transmitted by a receiving device (eg, STA or HE Beamformee) to a transmitting device (eg, AP or HE Beamformer).

First, referring to FIG. 18 , an example of a MIMO control field in a compressed beamforming frame according to an embodiment of the present disclosure is illustrated.

18 , a plurality of partial bandwidths (two or more partial bandwidths, each partial bandwidth may consist of one RU or a set of a plurality of adjacent RUs; for example, 996 of FIG. 8A ) This is a case regarding a compressed beamforming frame including subcarrier index information corresponding to each of two RUs (in one partial bandwidth configuration) in one MIMO control field. That is, when a receiving device (eg, STA or HE Beamformee) receives a request for channel state information for multiple RUs through an NDPA frame from a transmitting device (eg, AP or HE Beamformer), compression beamforming of FIG. 18 The frame may include a plurality of partial bandwidth information subfields each indicating subcarrier indexes corresponding to each partial bandwidth (for reference, each partial bandwidth is not adjacent to each other) in one MIMO control field. That is, the receiving device performs the same indexing as the transmitting device (eg, [matching RU Index] to display 'first subcarrier index information' and 'last subcarrier index information' corresponding to each RU in the MIMO control field. S, E] values) can be used, and detailed contents thereof will be described below. For reference, for convenience of description, in the embodiment of the present disclosure, a compressed beamforming frame including two partial bandwidth information subfields in one MIMO control field will be described as an example.

Specifically, although not shown in the drawings, the compressed beamforming frame may be included in a payload of a PPDU (more specifically, a data field of the payload). In addition, the compressed beamforming frame may include a MIMO control field (ie, a MIMO Control field).

MIMO control fields include 'Nc Index' subfield, 'Nr Index' subfield, 'BW' subfield, 'Grouping' subfield, 'Codebook Information' subfield, 'Feedback Type' subfield, 'Remaining Feedback Segments' subfield field, 'First Feedback Segment' subfield, 'RU Start Index' subfield, 'RU End Index' subfield, 'Sounding Dialog Token Number' subfield, 'Disallowed Subchannel Bitmap Present' subfield, 'Reserved' subfield ( In addition to the subfields placed before the 'Disallowed Subchannel Bitmap' subfield), the 'Disallowed Subchannel Bitmap' subfield, and the 'Reserved' subfield (subfields placed after the 'Disallowed Subchannel Bitmap' subfield), the '2 ^nd RU Start-End Index Present' subfield may be further included.

Here, as shown in FIG. 18, 'Nc Index' subfield, 'Nr Index' subfield, 'BW' subfield, 'Grouping' subfield, 'Codebook Information' subfield, 'Feedback Type' subfield , 'Remaining Feedback Segments' subfield, 'First Feedback Segment' subfield, 'RU Start Index' subfield, 'RU End Index' subfield, 'Sounding Dialog Token Number' subfield, 'Disallowed Subchannel Bitmap Present' subfield , some of 'Reserved' subfields (subfields placed before 'Disallowed Subchannel Bitmap' subfield), 'Disallowed Subchannel Bitmap' subfields, and 'Reserved' subfields (subfields placed after 'Disallowed Subchannel Bitmap' subfield) may be configured according to the 802.11ax standard, and the rest may be newly configured to comply with 802.11be or later standards.

In particular, the 'RU Start Index' subfield and the 'RU End Index' subfield may be configured with, for example, 8 bits to represent a maximum bandwidth of 320 MHz according to the 802.11be standard. Accordingly, the 'RU Start Index' subfield and the 'RU End Index' subfield may each have, for example, any one of indices from 0 to 255. Of course, the 'RU Start Index' and the 'RU End Index' may each consist of bits smaller than 8 bits (eg, 4 bits, 6 bits, or 7 bits).

In addition, the 'RU Start Index' subfield and the 'RU End Index' subfield may together form a partial bandwidth information subfield including subcarrier index information corresponding to a partial bandwidth designated as a channel feedback period of the corresponding receiving device. . That is, the partial bandwidth information subfield includes the first partial bandwidth start index subfield including the first subcarrier index information corresponding to the partial bandwidth and the end of the first partial bandwidth including the last subcarrier index information corresponding to the partial bandwidth It may include an index subfield. In addition, the first partial bandwidth start index subfield may correspond to the 'RU Start Index' subfield, and the first partial bandwidth end index subfield may correspond to the 'RU End Index' subfield.

On the other hand, the '2 ^nd RU Start-End Index Present' subfield may consist of 1 bit, and whether there is an additional partial bandwidth indicating whether there is an additional partial bandwidth designated as a channel feedback period of the corresponding receiving device in addition to the partial bandwidth. It may be a subfield.

That is, in the compressed beamforming frame of FIG. 18, unlike the HE compressed beamforming frame, a '2 ^nd RU Start-End Index Present' subfield may be newly added, and the receiving device transmits a '2 ^nd RU Start-End Index Present Present' subfield. It is possible to indicate whether there is an additional partial bandwidth designated as a channel feedback period of the corresponding receiving device through the ' subfield.

Specifically, when there is an additional partial bandwidth designated as the channel feedback period of the corresponding receiving device, the value of the '2 ^nd RU Start-End Index Present' subfield may be '1', and as the channel feedback period of the corresponding receiving device, the subfield value may be '1'. When the designated additional partial bandwidth does not exist, ^{the value of the '2 nd} RU Start-End Index Present' subfield may be '0'.

Furthermore, when there is an additional partial bandwidth designated as the channel feedback period of the corresponding receiving device (that is, when ^{the value of the '2 nd} RU Start-End Index Present' subfield is 1), the MIMO control field is '2 ^nd RU Start' It may further include a 'Index' subfield and a '2 ^nd RU End Index' subfield. On the other hand, when the additional partial bandwidth designated as the channel feedback period of the corresponding receiving device does not exist (that is, when ^{the value of the '2 nd} RU Start-End Index Present' subfield is 0), the MIMO control field relates to the partial bandwidth As the index subfield, only the 'RU Start Index' subfield and the 'RU End Index' subfield may be included.

Here, the '2 ^nd RU Start Index' subfield and the '2 ^nd RU End Index' subfield may be configured with, for example, 8 bits to represent a maximum bandwidth of 320 MHz according to the 802.11be standard. Accordingly, the '2 ^nd RU Start Index' subfield and the '2 ^nd RU End Index' subfield may have, for example, any one of indices from 0 to 255. Of course, the '2 ^nd RU Start Index' and the '2 ^nd RU End Index' may each consist of bits smaller than 8 bits (eg, 4 bits, 6 bits, or 7 bits).

In addition, the '2 ^nd RU Start Index' subfield and the '2 ^nd RU End Index' subfield are additional partial bandwidth information subfields including subcarrier index information corresponding to the additional partial bandwidth designated as the channel feedback period of the corresponding receiving device. can be configured together. That is, the additional partial bandwidth information subfield includes a second partial bandwidth start index subfield including first subcarrier index information corresponding to the additional partial bandwidth and a second partial bandwidth starting index subfield including last subcarrier index information corresponding to the additional partial bandwidth It may include a partial bandwidth end index subfield. In addition, a second portion bandwidth start index sub-field corresponds to the '2 ^nd RU Start Index' sub-field, the second end portion of the bandwidth index sub-field may correspond to '2 ^nd End RU Index' subfields.

For reference, the '2 ^nd RU Start Index' subfield and the '2 ^nd RU End Index' subfield are ^{disposed after the '2 nd} RU Start-End Index Present' subfield and may exist in the MIMO control field.

As described above, an example of a MIMO control field in a compressed beamforming frame according to an embodiment of the present disclosure is configured, and the transmitting apparatus is configured with multiple RUs (ie, multiple RUs composed of a plurality of partial bandwidths) as a channel feedback period. When transmitting the NDPA frame shown in any one of FIGS. 9, 10, and 12 to the receiving device, the corresponding receiving device only receives status information of a channel assigned to the receiving device in the MIMO control field in the compressed beamforming frame shown in FIG. can be used to transmit feedback to the transmitting device. Accordingly, a problem in which unnecessary overhead increases in the channel state information feedback process can be prevented.

As such, an example of a MIMO control field in a compressed beamforming frame according to an embodiment of the present disclosure may be configured to support a multi-RU designation situation and 802.11be standard (+ 802.11be or later standard).

Meanwhile, referring to FIG. 19 , another example of a MIMO control field in a compressed beamforming frame according to an embodiment of the present disclosure is illustrated.

In the case of FIG. 19, unlike FIG. 18, a plurality of partial bandwidths (two or more partial bandwidths, each partial bandwidth may consist of one RU or a set of a plurality of adjacent RUs; for example , in order to include subcarrier index information corresponding to each of the two 996 RUs of FIG. 8A in the MIMO control field in the MIMO control field, the partial bandwidth information subfield (that is, the partial bandwidth start/end index subfield) instead of the RU This case relates to a compressed beamforming frame to which an allocation subfield is added. That is, when a receiving device (eg, STA or HE Beamformee) receives a request for channel state information for multiple RUs through an NDPA frame from a transmitting device (eg, AP or HE Beamformer), the compressed beamforming of FIG. The frame may include an RU allocation subfield indicating a feedback period of the corresponding receiving device in the MIMO control field, and detailed contents thereof will be described below.

Specifically, although not shown in the drawings, the compressed beamforming frame may be included in a payload of a PPDU (more specifically, a data field of the payload). In addition, the compressed beamforming frame may include a MIMO control field (ie, a MIMO Control field).

MIMO control fields include 'Nc Index' subfield, 'Nr Index' subfield, 'BW' subfield, 'Grouping' subfield, 'Codebook Information' subfield, 'Feedback Type' subfield, 'Remaining Feedback Segments' subfield field, 'First Feedback Segment' subfield, 'Sounding Dialog Token Number' subfield, 'Disallowed Subchannel Bitmap Present' subfield, 'Reserved' subfield (subfield placed before 'Disallowed Subchannel Bitmap' subfield), 'Disallowed' In addition to the 'Subchannel Bitmap' subfield and the 'Reserved' subfield (a subfield disposed after the 'Disallowed Subchannel Bitmap' subfield), the 'RU Allocation' subfield may be further included.

Here, as shown in FIG. 19, 'Nc Index' subfield, 'Nr Index' subfield, 'BW' subfield, 'Grouping' subfield, 'Codebook Information' subfield, 'Feedback Type' subfield , 'Remaining Feedback Segments' subfield, 'First Feedback Segment' subfield, 'Sounding Dialog Token Number' subfield, 'Disallowed Subchannel Bitmap Present' subfield, 'Reserved' subfield (placed before 'Disallowed Subchannel Bitmap' subfield) subfield), 'Disallowed Subchannel Bitmap' subfield, and 'Reserved' subfield (a subfield placed after the 'Disallowed Subchannel Bitmap' subfield) may be configured according to the 802.11ax standard, and the rest are 802.11be It can be reconfigured to conform to the standard.

In particular, the 'RU Allocation' subfield is configured with a specific number of bits (eg, composed of 9 bits; for reference, the 'RU Allocation' subfield of FIG. 12 ) to express a maximum 320 MHz bandwidth according to the 802.11be standard field), and may include index information of a resource unit (RU) designated as a channel feedback period of the corresponding receiving device. And the index information on the RU may indicate the size and location of the RU.

Of course, if a bandwidth of 320 MHz can be expressed, the 'RU Allocation' subfield may be configured with a number of bits other than 9 bits (eg, 10 bits or more or 8 bits or less). For example, when the minimum RU size is set to 242-tone RU rather than 26-tone RU, the 'RU Allocation' subfield may express a bandwidth of 320 MHz with only 7 bits. However, in the embodiment of the present disclosure, for convenience of description, an example in which the 'RU Allocation' subfield consists of 9 bits will be described.

For reference, the transmitter may find subcarrier index information corresponding to the corresponding index information using the mapping table stored therein based on the index information of the 'RU Allocation' subfield. Here, the mapping table may include, for example, the tables of FIGS. 14 to 16 described above, but is not limited thereto. In addition, subcarrier index information corresponding to the index information of the 'RU Allocation' subfield (eg, 'RU Start Index' and 'RU End Index' corresponding to the specified RU) is generally a subcarrier index within the specified RU range. However, depending on circumstances, it may point to a subcarrier index outside the designated RU range to avoid extra-interpolation.

As such, in the compressed beamforming frame of FIG. 19, unlike the HE compressed beamforming frame, a 'RU Allocation' subfield may be newly added instead of the 'RU Start Index' subfield and the 'RU End Index' subfield, and receive The device may indicate a section fed back by the corresponding receiving device through the 'RU Allocation' subfield.

Accordingly, the transmitting device (eg, AP or HE Beamformer) is fed back to itself based on the 'RU Allocation' subfield in the compressed beamforming frame provided from the receiving device (eg, STA or HE Beamformee). can confirm.

As described above, another example of the MIMO control field in the compressed beamforming frame according to an embodiment of the present disclosure is configured, and the transmitting apparatus receives multi-RU (multi-RU composed of a plurality of partial bandwidths) allocated as a channel feedback period. When transmitting the NDPA frame shown in any one of FIGS. 9, 10, and 12 to the device, the receiving device receives only the state information of the channel assigned to it, the MIMO control field in the compressed beamforming frame shown in FIG. feedback can be transmitted to the transmitting device. Accordingly, a problem in which unnecessary overhead increases in the channel state information feedback process can be prevented.

As such, another example of the MIMO control field in the compressed beamforming frame according to an embodiment of the present disclosure may be configured to support a multi-RU designation situation and 802.11be standard (+ 802.11be or later standard).

As described above, an embodiment of the present disclosure improves data rate by preventing unnecessary overhead increase in the channel state information feedback process through an apparatus and method for supporting an efficient channel state information feedback of a user in a WLAN system can do.

Although the present disclosure has been described with reference to the embodiment shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible therefrom. Accordingly, the true technical protection scope of the present disclosure should be determined by the technical spirit of the appended claims.

Claims (18)

In the baseband circuit provided in the transmission device of the WLAN (wireless local area network) system,
storage;
a control unit for writing or reading data to the storage unit; and
A signal processing unit that is controlled by the control unit and generates a Physical Layer Convergence Protocol (PLCP) protocol data unit (PPDU) including a preamble and a payload,
The data field of the payload includes a Null Data Packet Announcement (NDPA) frame,
The NDPA frame includes a MAC header (Medium Access Control Header) and a frame body,
The frame body includes a first user information field applied to a receiving device to receive the PPDU from the transmitting device,
The first user information field includes a partial bandwidth information subfield including subcarrier index information corresponding to a partial bandwidth designated as a channel feedback section of the receiving device, and an additional part designated as a channel feedback section of the receiving device other than the partial bandwidth Including an additional partial bandwidth presence subfield indicating whether bandwidth exists
baseband circuit.
According to claim 1,
When there is an additional partial bandwidth designated as a channel feedback period of the receiving device,
The frame body further includes a second user information field applied to the receiving device,
The second user information field includes a partial bandwidth information subfield including subcarrier index information corresponding to the additional partial bandwidth, and an additional partial bandwidth indicating that the additional partial bandwidth is designated as a channel feedback interval of the receiving device. a presence subfield and an identifier subfield having the same index as the identifier subfield of the first user information field
baseband circuit.
3. The method of claim 2,
The partial bandwidth information subfield of the first user information field includes first and last subcarrier index information corresponding to the partial bandwidth,
The partial bandwidth information subfield of the second user information field includes first and last subcarrier index information corresponding to the additional partial bandwidth.
baseband circuit.
3. The method of claim 2,
Each of the first and second user information fields has an additional partial bandwidth subfield composed of 1 bit.
baseband circuit.
The method of claim 1,
When there is an additional partial bandwidth designated as a channel feedback period of the receiving device,
The first user information field further includes an additional partial bandwidth information subfield including subcarrier index information corresponding to the additional partial bandwidth
baseband circuit.
6. The method of claim 5,
The partial bandwidth information subfield includes first and last subcarrier index information corresponding to the partial bandwidth,
The additional partial bandwidth information subfield includes first and last subcarrier index information corresponding to the additional partial bandwidth.
baseband circuit.
6. The method of claim 5,
The additional partial bandwidth presence subfield is composed of 1 bit
baseband circuit.
In the baseband circuit provided in the transmission device of the WLAN (wireless local area network) system,
storage;
a control unit for writing or reading data to the storage unit; and
A signal processing unit that is controlled by the control unit and generates a Physical Layer Convergence Protocol (PLCP) protocol data unit (PPDU) including a preamble and a payload,
The data field of the payload includes a Null Data Packet Announcement (NDPA) frame,
The NDPA frame includes a MAC header (Medium Access Control Header) and a frame body,
The frame body includes a user information field applied to a receiving device to receive the PPDU from the transmitting device,
The user information field includes an RU allocation subfield including index information of a resource unit (RU) designated as a channel feedback period of the receiving device.
baseband circuit.
9. The method of claim 8,
The index information of the RU indicates the size and location of the RU.
baseband circuit.
In the baseband circuit provided in the receiving device of the WLAN (wireless local area network) system,
storage;
a control unit for writing or reading data to the storage unit; and
Controlled by the control unit, including a signal processing unit for decoding a PPDU (Physical Layer Convergence Protocol (PLCP) protocol data unit) received from the transmitting device,
The PPDU includes a preamble and a payload,
The data field of the payload includes a Null Data Packet Announcement (NDPA) frame,
The NDPA frame includes a MAC header (Medium Access Control Header) and a frame body,
The frame body includes a first user information field applied to the receiving device,
The first user information field includes a partial bandwidth information subfield including subcarrier index information corresponding to a partial bandwidth designated as a channel feedback section of the receiving device, and an additional part designated as a channel feedback section of the receiving device other than the partial bandwidth Including an additional partial bandwidth presence subfield indicating whether bandwidth exists
baseband circuit.
11. The method of claim 10,
When there is an additional partial bandwidth designated as a channel feedback period of the receiving device,
The frame body further includes a second user information field applied to the receiving device,
The second user information field includes a partial bandwidth information subfield including subcarrier index information corresponding to the additional partial bandwidth, and an additional partial bandwidth indicating that the additional partial bandwidth is designated as a channel feedback interval of the receiving device. a presence subfield and an identifier subfield having the same index as the identifier subfield of the first user information field
baseband circuit.
12. The method of claim 11,
The partial bandwidth information subfield of the first user information field includes first and last subcarrier index information corresponding to the partial bandwidth,
The partial bandwidth information subfield of the second user information field includes first and last subcarrier index information corresponding to the additional partial bandwidth.
baseband circuit.
12. The method of claim 11,
Each of the first and second user information fields has an additional partial bandwidth subfield composed of 1 bit.
baseband circuit.
11. The method of claim 10,
When there is an additional partial bandwidth designated as a channel feedback period of the receiving device,
The first user information field further includes an additional partial bandwidth information subfield including subcarrier index information corresponding to the additional partial bandwidth
baseband circuit.
15. The method of claim 14,
The partial bandwidth information subfield includes first and last subcarrier index information corresponding to the partial bandwidth,
The additional partial bandwidth information subfield includes first and last subcarrier index information corresponding to the additional partial bandwidth.
baseband circuit.
15. The method of claim 14,
The additional partial bandwidth presence subfield is composed of 1 bit
baseband circuit.
In the baseband circuit provided in the receiving device of the WLAN (wireless local area network) system,
storage;
a control unit for writing or reading data to the storage unit; and
Controlled by the control unit, including a signal processing unit for decoding a PPDU (Physical Layer Convergence Protocol (PLCP) protocol data unit) received from the transmitting device,
The PPDU includes a preamble and a payload,
The data field of the payload includes a Null Data Packet Announcement (NDPA) frame,
The NDPA frame includes a MAC header (Medium Access Control Header) and a frame body,
The frame body includes a user information field applied to the receiving device,
The user information field includes an RU allocation subfield including index information of a resource unit (RU) designated as a channel feedback period of the receiving device.
baseband circuit.
18. The method of claim 17,
The index information of the RU indicates the size and location of the RU.
baseband circuit.

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