Patent Description:
WLAN is a technology for wirelessly connecting two or more devices to each other, where the devices are located in a local environment such as a building or campus. A WLAN may in an infrastructure mode in which an access point (AP) serves multiple user devices such as smartphones and laptops, where the AP may serve as a gateway to a remote network, typically the Internet. A WLAN alternatively operates as an ad hoc network between peer devices without an AP. In either case, WLAN employs orthogonal frequency division multiplexing (OFDM) technology in which each user device communicates with an AP or another user device using an assigned set of OFDM subcarriers within an overall frequency band of the WLAN.

Currently, most WLAN technology is based on the institute of electrical and electronics engineers (IEEE) <NUM> standard. The IEEE <NUM> standard has been developed into <NUM>. 11b, <NUM>. 11a, <NUM>, <NUM>. 11n, <NUM>. 11ac, and <NUM>. 11ax versions and may support a transmission speed up to <NUM> Gbyte/s through use of OFDM technology. In version <NUM>. 11ac, data may be simultaneously transmitted to multiple users through a multi-user multi-input multi-output (MU-MIMO) scheme. 11ax (referred to as just "high efficiency" (HE)), by providing available subcarriers to users in a divided manner with orthogonal frequency division multiple access (OFDMA) technology, in conjunction with applying MU-MIMO, multiple access is implemented. The WLAN system to which <NUM>. 11ax is applied may effectively support communication in a crowded area and outdoors.

Another recent version, <NUM>. 11be (extremely high throughput (EHT)), is slated to support a <NUM> unlicensed frequency band, a bandwidth up to <NUM> per channel, hybrid automatic repeat and request (HARQ), and up to 16X16 MIMO. Therefore, a next generation WLAN system is expected to effectively support low latency and ultra-fast transmission with performance metrics similar to new radio (NR) <NUM> technology. <CIT> discloses a wireless communication terminal including a processor and a transceiver, wherein the processor receives a wireless packet through the communication unit, obtains total bandwidth information indicated via a bandwidth field of HE-SIG-A of the received packet, obtains information of an unassigned resource unit via at least one of the bandwidth field of the HE-SIG-A and a subfield of HE-SIG-B of the received packet, and decodes the received packet based on the total bandwidth information and the information of the unassigned resource unit and a wireless communication method using the same. <CIT> discloses a method and device for receiving data in a wireless LAN system. Specifically, an AP transmits a trigger frame to a first to a third station (STA) through a multi-band. The AP receives data from the first to third STAs on the basis of the trigger frame. <CIT> discloses a resource unit indication method and apparatus, and a storage medium, where the method includes: an access point (AP) sending a physical protocol data unit (PPDU) to a plurality of stations (STAs), where a transmission bandwidth of the PPDU is divided into M subblocks. <CIT> discloses techniques to indicate operations by extremely high throughput (EHT) devices on an operating bandwidth, including devices in a basic service set (BSS) supporting the use of a <NUM> channel. In some aspects, the supported functionality may include extensions to flexibility and support rules, structures, and signaling using legacy fields, frames, and features. In addition, the supported functionality may include channel sensing and reporting, such as per-channel network allocation vectors (NAVs) for the sub-channels of the operating bandwidth. <CIT> discloses computer programs encoded on computer storage media, for multiplexing clients of different generations in trigger-based transmissions, including trigger-based transmissions in extremely-high throughput (EHT) Wi-Fi systems. An access point (AP) may generate a trigger frame compatible with two types of stations (STAs), such as EHT STAs and legacy (or high efficiency (HE)) STAs. The AP may transmit the trigger frame to a group of STAs, where legacy STAs may process the trigger frame a legacy trigger frame. <CIT> discloses a method of wireless communication comprising at a transmit station, allocating multiple RUs to a receive station for an OFDMA transmission, setting a first field of a preamble of a PLCP protocol data unit PPDU to specify the multiple RUs allocated to the receive station, setting multiple user fields in said preamble of said PPDU, each comprising an STA ID of said receive station in correspondence to a respective RU of the multiple RUs; and transmitting said PPDU to the receive station. <CIT> discloses methods for SIG Design for OFDMA in WLAN Systems. Data may be mapped to a plurality of OFDM symbols of the PDU. Each of the plurality of OFDM symbols may be associated with a first duration and a first length of data. A second length of data to be transmitted in a last OFDM symbol of the plurality of OFDM symbols may be determined to be less than the first length of data. The last OFDM symbol may be modified, for example, based on the second length of data, from the first duration to a second duration. The second duration may be <NUM>/<NUM>, <NUM>/<NUM>, or <NUM>/<NUM> of the first duration. An indication of the second duration of the last OFDM symbol may be sent.

Embodiments of the inventive concept provide a method of efficiently allocating a multi-RU to a user within an extended uplink bandwidth in a wireless local area network (WLAN) system.

The invention provides a method as claimed in claim <NUM>.

As least some of the above and other features of the invention are set out in the claims.

Embodiments of the inventive concept will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings in which like reference characters refer to like elements throughout, wherein:.

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

Terms used herein are for describing embodiments and are not for limiting the inventive concept. Herein, a singular form includes a plural form unless specially described. Described components, processes, operations and/or elements do not exclude the presence or addition of one or more other components, processes, operations and/or elements.

Unless otherwise defined, all the terms (including technological and scientific terms) used herein may be used in the meaning that may be commonly understood by those skilled in the art. In addition, terms defined in a commonly used dictionary are not ideologically or excessively interpreted unless specially defined.

In addition, in specifically describing the embodiments of the inventive concept, OFDM or an OFDM-based wireless communication system, in particular, the IEEE <NUM> standard is to be mainly described. However, the inventive concept may also be applied to other communication systems with a similar technological background and channel type (for example, a cellular communication system such as long term evolution (LTE), LTE-Advanced (LTE-A), new radio (NR) / <NUM>, wireless broadband (WiBro), or global system for mobile communication (GSM) or a remote communication system such as Bluetooth or near field communication (NFC).

Herein, the term "connects (combines)" and derivatives thereof refer to direct or indirect communication between two or more components that physically contact or do not physically contact. The terms "transmits", "receives", and "communicates" and derivatives thereof include all direct and indirect communication. "Comprises" and/or "comprising" used herein mean inclusion without limit. "Or" is a collective term meaning 'and/or'. "Is related to ~" and derivatives thereof mean includes, is included in ~, is connected to ~, implies, is implied in ~, is connected to ~, is combined with ~, may communicate with ~, cooperates with ~, interposes, puts in parallel, is close to ~, is bound to ~, has, has a feature of ~, and has a relation with ~. "A controller" means a certain device, system, or a part thereof controlling at least one operation. The controller may be implemented by hardware or a combination of hardware and software and/or firmware. A function related to a specific controller may be locally or remotely concentrated or dispersed.

In addition, various functions described hereinafter may be implemented or supported by one or more computer programs and each of the programs is formed of computer-readable program code and is executed in a computer-readable recording medium. "An application" and "a program" refer to one or more computer programs, software components, instruction sets, processes, functions, objects, classes, instances, related data, or parts thereof suitable for implementation of pieces of computer-readable program code. "Computer-readable program code" include all types of computer code including source code, object code, and execution code. "Computer-readable media" include all types of media that may be accessed by a computer such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disk (CD), a digital video disk (DVD), and other types of memory. "Non-transitory" computer-readable media exclude wired, wireless, optical, or other communication links transmitting temporary electrical or other signals. Non-temporary computer-readable media include a medium in which data may be permanently stored and a medium in which data may be stored and may be overwritten later such as a rewritable optical disk or a deletable memory device.

Herein, the terms "subcarrier" and "tone" may be used interchangeably, and a "size of an RU" means a number of tones of an RU.

Herein, a "leftmost side of a band" refers to a range of frequencies within the band starting at the lowest frequency within the band.

<FIG> is a view illustrating a wireless local area network (WLAN) system <NUM>. <FIG> is a block diagram illustrating a wireless communication device <NUM> transmitting or receiving a physical layer convergence protocol (PLCP) protocol data unit (PPDU). As illustrated in <FIG>, the WLAN system <NUM> may include access points (AP) <NUM> and <NUM>. The APs <NUM> and <NUM> may communicate with at least one network <NUM> such as the Internet, an internet protocol (IP) network, or a private data network.

The APs <NUM> and <NUM> may provide wireless connection to the network <NUM> for a plurality of stations (STAs) <NUM> to <NUM> in coverage areas <NUM> and <NUM> thereof. The APs <NUM> and <NUM> may communicate with each other and with the STAs <NUM> to <NUM> by using WiFi or other WLAN communication technologies. Herein, AP may be referred to a first device or a transmitting device, and STA may be referred to a second device or a receiving device.

For example, in accordance with a network type, other well-known terms such as "a router" and "a gateway" may be used instead of "the AP". In addition, in the WLAN, the AP is provided for a wireless channel. An AP may operate as a STA in some scenarios, such as when a first AP communicates with a second AP, and the second AP operates as a STA based on control information provided by the first AP.

In addition, in accordance with the network type, "STA" may be used instead of other well-known terms such as "a mobile station", "a subscriber station", "a remote terminal", "user equipment", "a wireless terminal", "a user device", or "a user". For convenience, herein, "STA" is used for representing a remote wireless device wirelessly connected to the AP or connected to the wireless channel in the WLAN. Herein, a STA is considered as a mobile device (e.g., a mobile telephone or a smartphone). In other examples, a STA is a fixed device (e.g., a desktop computer, the AP, a media player, a fixed sensor, or a television set).

Approximate extents of the coverage areas <NUM> and <NUM> are marked with dashed lines. Here, the coverage areas <NUM> and <NUM> are illustrated as being circular for simplicity of explanation. However, each of the coverage areas <NUM> and <NUM> related to the APs <NUM> and <NUM> may have another shape to which a varying change in wireless environment related to a natural or artificial obstruction is reflected or another irregular shape in accordance with setting of the APs <NUM> and <NUM>.

As described in detail later, the APs <NUM> and <NUM> may include circuitry and/or a program for managing transmission of an uplink multiuser (ULMU) or a downlink multiuser (DLMU) in the WLAN system <NUM>.

In other examples, the WLAN system <NUM> may include an arbitrary number of properly arranged APs and an arbitrary number of STAs. In addition, the AP <NUM> may directly communicate with an arbitrary number of STAs. The AP <NUM> may provide wireless broadband access to the plurality of STAs <NUM> to <NUM> via the network <NUM>.

Similarly, each of the APs <NUM> and <NUM> may directly communicate with the network <NUM> and may provide wireless broadband access to the plurality of STAs <NUM> to <NUM> via the network <NUM>. In addition, the APs <NUM> and <NUM> may be configured to connect to a varying external network such as an external telephone network or a data network.

As depicted in <FIG>, a wireless communication device transmitting or receiving the PPDU is illustrated. For example, the wireless communication device <NUM> of <FIG> may be a transmission device (e.g., an AP) or a receiving device (e.g., a STA) with a transceiver capable of performing data communication. That is, the wireless communication device <NUM> of <FIG> may be one of the APs <NUM> and <NUM> and the plurality of STAs <NUM> to <NUM> illustrated in <FIG> and may be applied to a sensor used for, for example, a computer, a smartphone, a portable electronic device, a tablet, a wearable device, or an Internet of Things (IoT). In the following description, a STA is an example of a "receiving device". Moreover, the terms "user" and "STA" may be used interchangeably. Further, an AP is an example of a "transmitting device" in the following description.

For ease of explanation, hereinafter, a case in which the wireless communication device <NUM> is the transmission device is taken as an example.

The wireless communication device <NUM> may include a main processor <NUM>, memory <NUM>, a transceiver <NUM>, and antenna arrays <NUM> to <NUM>. The main processor <NUM>, the memory <NUM>, the transceiver <NUM>, and the antenna arrays <NUM> to <NUM> may be directly or indirectly connected to each other.

The main processor <NUM> may control the memory <NUM> and the transceiver <NUM>. A PPDU format and multiple resource unit (RU) allocation information may be stored in the memory <NUM>. The transceiver <NUM> may generate the PPDU by using the PPDU format and the multiple RU allocation information stored in the memory <NUM>. The transceiver <NUM> may transmit the generated PPDU to an external receiving device through the antenna arrays <NUM> to <NUM>.

Here, the memory <NUM> may store a PPDU format <NUM> including a RU allocation signaling format according to an embodiment of the inventive concept, which will be described later. The memory <NUM> may store processor-executable instructions executing a RU allocation module <NUM> and a PPDU generation module <NUM>. The processor-executable instructions may be executed by the main processor <NUM>, in which case circuitry of the main processor <NUM> performs the functions of the RU allocation module <NUM> and the PPDU generation module <NUM>; accordingly, these modules may interchangeably be called RU allocation circuitry <NUM> and PPDU generation circuitry, respectively.

For example, the RU allocation module <NUM> may use an RU allocation algorithm, method, or policy to allocate at least one RU (e.g., a single RU or a multiple RU) to a user according to an embodiment of the inventive concept. The PPDU generation module <NUM> may generate signaling and indication related to allocation of the at least one RU in a trigger frame of the PPDU.

On the other hand, the transceiver <NUM> may include a signal processor <NUM>. The signal processor <NUM> may include various transmission path modules generating sections of the PPDU or various types of communication transmission units.

The signal processor <NUM> may include a transmit first-in-first-out (TX FIFO) <NUM>, an encoder <NUM>, a scrambler <NUM>, an interleaver <NUM>, a constellation mapper <NUM> capable of, for example, generating a QAM symbol, a guard interval and windowing insertion module <NUM> capable of, for example, providing a guard interval on a frequency to reduce interference on a spectrum and transforming a signal through windowing, and an inversed discrete Fourier transformer (IDFT) <NUM>.

It is noted that the transceiver <NUM> may include parts well-known to those skilled in the art as illustrated in the drawing. The corresponding parts may be executed by a method well-known to those skilled in the art by using hardware, firmware, software logic, or a combination of hardware, firmware, and software logic.

When the wireless communication device <NUM> is a receiving device, the transceiver <NUM> illustrated in <FIG> may include components in a receiving path.

That is, when the wireless communication device <NUM> is a receiving device, the transceiver <NUM> may receive the PPDU including a trigger frame from the transmission device. The transceiver <NUM> may decode the trigger frame included in the received PPDU. That is, the transceiver <NUM> may identify an RU allocated for the receiving device by decoding the trigger frame through an internal decoder (not shown), decode the trigger frame, identify at least one RU allocated to uplink bandwidth and the receiving device and transmit PPDU to the transmitting device based on the identified at least one RU. Alternatively, the decoding may be performed by a component other than the transceiver <NUM>, e.g., the main processor <NUM>.

Hereinafter, high efficiency (HE) PPDUs used in the institute of electrical and electronics engineers (IEEE) standard (that is, <NUM>. 11ax) will be described with reference to <FIG>. For example, the HE PPDUs described with reference to <FIG> may be generated by the wireless communication device <NUM> of <FIG>.

<FIG> is a view illustrating a structure of an HE single user (SU) PPDU. <FIG> is a view illustrating a structure of an HE extended range (ER) SU PPDU. <FIG> is a view illustrating a structure of an HE trigger based (TB) PPDU. <FIG> is a view illustrating a structure of an HE multiuser (MU) PPDU. As illustrated in <FIG>, each HE PPDU may include a preamble including a plurality of training fields and a plurality of signaling fields and a payload including a data (DATA) field and a packet extension (PE) field.

Each HE PPDU may include a legacy-short training field (L-STF) with a length of <NUM>, a legacy-long training field (L-LTF) with a length of <NUM>, a legacy-signal (L-SIG) field with a length of <NUM>, a repeated L-SIG (RL-SIG) field with a length of <NUM>, a high efficiency-signal-A (HE-SIG-A) field with a length of <NUM>, an HE-STF with a length of <NUM>, an HE-LTF, a DATA field, and a PE field.

The HE SU PPDU of <FIG> does not include an HE-SIG-B field, and the HE MU PPDU of <FIG> may further include the HE-SIG-B field. The HE ER SU PPDU of <FIG> does not include the HE-SIG-B field. However, a symbol of the HE-SIG-A field may be repeated with a length of <NUM>. In addition, the HE TB PPDU of <FIG> does not include the HE-SIG-B field. However, a symbol of the HE-STF may be repeated with a length of <NUM>.

Here, the fields included in the preamble will be simply described as follows.

The L-STF may include a short training orthogonal frequency division multiplexing (OFDM) symbol and may be used for frame detection, automatic gain control (AGC), diversity detection, and coarse frequency/time synchronization.

The L-LTF may include a long training OFDM symbol and may be used for fine frequency/time synchronization and channel estimation.

The L-SIG field may be used for transmitting control information and may include information on a data rate and a data length. For example, the L-SIG field may be repeatedly transmitted. A format in which the L-SIG field is repeated is referred to as the RL-SIG field.

The HE-SIG-A field may include control information common to the receiving device, which is as follows:.

The HE-SIG-A field may further include various information items other than the above-described <NUM>) to <NUM>) or may not include partial information items among the above-described <NUM>) to <NUM>). In environments other than an MU environment, partial information items may be further added to the HE-SIG-A field or partial information items of the HE-SIG-A field may be omitted.

The HE-SIG-B field may be used for the PPDU for the MU. Thus, the HE-SIG-B field may be omitted from the PPDU for the SU. For example, because the HE-SIG-A field or the HE-SIG-B field may include RU allocation information on at least one receiving device for downlink transmission. The PE field may have duration of <NUM>, <NUM>, <NUM>, or <NUM> and may provide an additional receive processing time at an end of the HE PPDU.

<FIG> is a view illustrating a structure of an EHT TB PPDU. <FIG> is a view illustrating a structure of an EHT MU PPDU. An embodiment of the inventive concept may also be applied to <NUM>. 11be, which is a next generation WLAN standard. Therefore, because the method and the apparatus for allocating the RU according to an embodiment of the inventive concept may be implemented in signaling fields (for example, extremely high throughout (EHT)-SIG fields) of EHT PPDUs, hereinafter, with reference to <FIG> and <FIG>, the EHT PPDUs used in the IEEE standard (that is, <NUM>. 11be) will be described. For reference, the EHT PPDUs described with reference to <FIG> and <FIG> may be generated by the wireless communication device <NUM> of <FIG>.

As illustrated in <FIG> and <FIG>, each EHT PPDU may include a preamble including a plurality of training fields and a plurality of signaling fields and a payload including a data field.

Each EHT PPDU may include an L-STF with a length of <NUM>, an L-LTF with a length of <NUM>, an L-SIG field with a length of <NUM>, a repeated L-SIG (RL-SIG) field with a length of <NUM>, a universal-signal (U-SIG) field with a length of <NUM>, an EHT-STF, an EHT-LTF, and a DATA field.

The EHT TB PPDU of <FIG> does not include an EHT-SIG field. However, a symbol of the EHT-STF may be repeated. The EHT MU PPDU of <FIG> may consist of a plurality of OFDM symbols and may further include the EHT-SIG field. In addition, like the above-described HE TB PPDU of <FIG>, the EHT TB PPDU of <FIG> may require a trigger frame to transmit the EHT TB PPDU. The trigger frame for transmitting the EHT TB PPDU may have a structure and a function similar to those of a trigger frame of <FIG> described later.

For example, a PE field may be further included in each EHT PPDU. The figures herein, however, illustrate EHT PPDUs without PE field.

Fields included in each EHT PPDU will be simply described as follows.

Because 'the L-STF', 'the L-LTF', 'the L-SIG field', and 'the RL-SIG field' of each EHT PPDU are the same as or similar to 'the L-STF', 'the L-LTF', 'the L-SIG field', and 'the RL-SIG field' of the above-described HE PPDU, detailed description thereof will be omitted.

The U-SIG field performing a function similar to that of the HE-SIG-A field of the HE PPDU may be arranged immediately next to the RL-SIG field and may include commonly encoded two OFDM symbols.

The U-SIG field may include 'version-independent fields' and 'version-dependent fields' and 'the version-dependent fields' may be arranged next to 'the version-independent fields'.

Here, 'the version-independent fields' may have static location and bit definition over different generations/physical versions.

In addition, 'the version-independent fields' may include, for example, next control information, as follows:.

On the other hand, 'the version-dependent fields' may have variable bit definition in each PHY version.

In addition, 'the version-dependent fields' may include, for example, next control information as follows:.

The U-SIG field may further include various information items other than the above-described control information or may not include partial information among the above-described control information items. In environments other than an MU environment, partial information may be further added to the U-SIG field or partial information of the U-SIG field may be omitted.

The EHT-SIG field performing a function similar to that of the HE-SIG-B field of the HE PPDU may be arranged immediately next to the U-SIG field in the EHT PPDU, which is transmitted to the MU, and may have a variable MCS and a variable length.

The EHT-SIG field may include a common field including common control information and a user-specific field including user-specific control information.

Here, the common field may be encoded apart from the user-specific field. In addition, the common field may include RU allocation related information for downlink transmission (for example, information including 'an RU allocation subfield' and 'an additional RU allocation subfield', which is described later) and the user-specific field may include information (that is, user information allocated for each RU) similar to information included in the user-specific field of the above-described HE-SIG-B field.

For example, in the common field of the EHT-SIG field of the EHT PPDU, which is transmitted to the MU, at least one compression mode in which 'the RU allocation subfield' is not provided may be provided. In addition, the EHT-SIG field may be basically used for the PPDU for the MU. However, unlike in 'the HE PPDU', when an overhead of the U-SIG field increases, the EHT-SIG field may be used for the PPDU for transmitting the SU.

<FIG> and <FIG> are diagrams illustrating examples of RU available in a <NUM> OFDMA PPDU and indexes thereof; <FIG> and <FIG> are diagrams illustrating examples of RU available in a <NUM> OFDMA PPDU and indexes thereof; <FIG> and <FIG> are diagrams illustrating examples of RU available in an <NUM> OFDMA PPDU and indexes thereof; <FIG> and <FIG> are diagrams illustrating examples of indexes of RU available in a <NUM> OFDMA PPDU. <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> are diagrams illustrating examples of indexes of RU available in a <NUM> OFDMA PPDU. That is, as illustrated in <FIG>, <FIG> and <FIG>, at least one RU may be arranged in the frequency domain of the data field (the horizontal axis of each of <FIG>, <FIG> and <FIG> represents the frequency domain). In <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG> and <FIG>, a zero index of subcarrier may correspond to a DC-tone, a negative index of subcarrier may correspond to a subcarrier having a frequency lower than the DC-tone, and a positive index of subcarrier may correspond to a subcarrier having a frequency higher than the DC-tone.

First, in <FIG>, the arrangement of the RU available in the <NUM> OFDMA PPDU is illustrated. In the leftmost band of a <NUM> band, six tones (that is, subcarriers) may be used as a guard band and, in the rightmost band of the <NUM> band, five tones may be used as a guard band. In addition, <NUM>-tone RUs, <NUM>-tone RUs, and <NUM>-tone RUs may be allocated for other bands. Seven direct current (DC) tones may be inserted into a central band, that is, a DC band and a <NUM>-tone RU corresponding to <NUM> tones may be provided on each of left and right sides of the DC band. Each RU may be allocated for a receiving device, that is, a user.

For example, the RU arrangement of <FIG> may be used for a situation for an SU as well as a situation for a MU. Therefore, as illustrated in the uppermost portion of <FIG>, a plurality of <NUM>-tone RUs may be arranged and, as illustrated in the lowermost portion of <FIG>, one <NUM>-tone RU including <NUM> and 242R may be arranged (in this case, three DC tones may be inserted into the central band).

Various sizes of RUs, that is, the <NUM>-tone RUs, the <NUM>-tone RUs, the <NUM>-tone RUs, and the <NUM>-tone RU are suggested in an example of <FIG>. In other examples, the sizes of the RUs may differ.

Referring to <FIG>, RUs in <FIG> may be indexed sequentially from the lowest frequency. For example, the <NUM>-tone RU may be indexed as first to ninth RUs RU1 to RU9, the <NUM>-tone RU may be indexed as first to fourth RUs RU1 to RU4, the <NUM>-tone RU may be indexed as first and second RUs RU1 and RU2, and <NUM>-tone RU may be indexed as a first RU RU1. A fifth RU is a central <NUM>-tone RU in <FIG>.

As shown in <FIG>, the arrangement of the RU available in the <NUM> OFDMA PPDU is illustrated. In the leftmost band of a <NUM> band, <NUM> tones (that is, subcarriers) may be used as a guard band and, in the rightmost band of the <NUM> band, <NUM> tones may be used as a guard band. In addition, five DC tones may be inserted into a central band, that is, a DC band. In addition, <NUM>-tone RUs, <NUM>-tone RUs, <NUM>-tone RUs, and <NUM>-tone RUs may be allocated for other bands. Each RU may be allocated for a receiving device, that is, a user.

Note that the RU arrangement of <FIG> may be used for a situation for a SU as well as a situation for a MU. Therefore, as illustrated in the lowermost portion of <FIG>, one <NUM>-tone RU including <NUM> and 484R may be arranged (in this case, five DC tones may be inserted into the central band).

Various sizes of RUs, that is, the <NUM>-tone RUs, the <NUM>-tone RUs, the <NUM>-tone RUs, the <NUM>-tone RUs, and the <NUM>-tone RU are suggested in an example of <FIG>. In other examples, the sizes of the RUs may differ.

Referring to <FIG>, RUs in <FIG> may be indexed sequentially from the lowest frequency. For example, the <NUM>-tone RU may be indexed as first to 18th RUs RU1 to RU18, the <NUM>-tone RU may be indexed as first to eighth RUs RU1 to RU8, the <NUM>-tone RU may be indexed as first to fourth RUs RU1 to RU4, the <NUM>-tone RU may be indexed as first and second RUs RU1 and RU2, and the <NUM>-tone RU may be indexed as a first RU RU1.

In <FIG>, the arrangement of the RU available in the <NUM> OFDMA PPDU is illustrated.

Specifically, in the leftmost band of an <NUM> band, <NUM> tones (that is, subcarriers) may be used as a guard band and, in the rightmost band of the <NUM> band, <NUM> tones may be used as a guard band. In addition, <NUM>-tone RUs, <NUM>-tone RUs, <NUM>-tone RUs, <NUM>-tone RUs, and <NUM>-tone RUs may be allocated for other bands. Each RU may be allocated for a receiving device, that is, a user.

The RU arrangement of <FIG> may be used for a situation involving an SU as well as one involving an MU. Therefore, as illustrated in the lowermost portion of <FIG>, one <NUM>-tone RU including <NUM> and 996R may be arranged (in this case, five DC tones may be inserted into the central band).

Various sizes of RUs, that is, the <NUM>-tone RU ("RU26"), the <NUM>-tone RU ("RU52"), the <NUM>-tone RU ("RU106"), the <NUM>-tone RU ("RU242"), the <NUM>-tone RU ("RU484"), and the <NUM>-tone RU ("RU996") are suggested in an example of <FIG>. However, the RU sizes may differ in other embodiments.

Referring to <FIG>, RUs in <FIG> may be indexed sequentially from the lowest frequency. For example, the <NUM>-tone RU may be indexed as first to 37th RUs RU1 to RU37, the <NUM>-tone RU may be indexed as first to 16th RUs RU1 to RU16, the <NUM>-tone RU may be indexed as first to eighth RUs RU1 to RU8, the <NUM>-tone RU may be indexed first to fourth RUs RU1 to RU4, the <NUM>-tone RU may be indexed as first and second RUs RU1 and RU2, and the <NUM>-tone RU may be indexed as a first RU RU1. The central <NUM>-tone RU may be used in HE (i.e., <NUM>. 11ax) but may not be used in EHT (i.e., <NUM>. In some embodiments, as illustrated in <FIG>, the central <NUM>-tone RU may be indexed as a 19th RU RU19. Accordingly, an indexing of RU in EHT may be compatible with an indexing of RU in HE.

Referring <FIG> and <FIG>, RUs in <NUM> OFDMA PPDU may be indexed sequentially from the lowest frequency. For example, the <NUM>-tone RU may be indexed as first to 74th RUs RU1 to RU74. As described with reference to <FIG>, the central <NUM>-tone RU in <NUM> bandwidth may not be used. Accordingly, the 19th RU RU19 and the 56th RU RU56 in <FIG> may not be used.

Referring to <FIG>, <FIG>, <FIG>, <FIG> and <FIG>, RUs in <NUM> bandwidth may be indexed sequentially from the lowest frequency. For example, the <NUM>-tone RU may be indexed as first to 148th RUs RU1 to RU148. As described with reference to <FIG>, the central <NUM>-tone RU in <NUM> bandwidth. Accordingly, the 19th RU RU19, the 56th RU RU56, the 93th RU RU93 and the 130th RU RU130 in <FIG> and <FIG> may not be used.

In some embodiments, RU positions available in the <NUM> OFDMA PPDU are the same as two replicas of RU positions available in the <NUM> OFDMA PPDU. In addition, RU positions available in the <NUM> OFDMA PPDU may be the same as two replicas of the RU positions available in the <NUM> OFDMA PPDU. In addition, RU positions available in the <NUM> OFDMA PPDU may be the same as two replicas of the RU positions available in the <NUM> OFDMA PPDU. In addition, RU positions available in the <NUM> OFDMA PPDU may be the same as two replicas of the RU positions available in the <NUM> OFDMA PPDU. Accordingly, in 160MH bandwidth, the <NUM>-tone RU may be indexed as first to 32th RUs RU1 to RU32, the <NUM>-tone RU may be indexed as first to 16th RUs RU1 to RU16, the <NUM>-tone RU may be indexed as first to <NUM> RUs RU1 to RU8, the <NUM>-tone RU may be indexed as first to fourth RUs RU1 to RU4, and the <NUM>-tone RU may be indexed as first and second RUs RU1 and RU2. Similarly, in <NUM> bandwidth, the <NUM>-tone RU may be indexed as first to <NUM> RUs RU1 to RU64, the <NUM>-tone RU may be indexed as first to <NUM> RUs RU1 to RU32, the <NUM>-tone RU may be indexed a s first to 16th RUs RU1 to RU16, the <NUM>-tone RU may be indexed as first to eighth RUs RU1 to RU8, and the <NUM>-tone RU may be indexed as first to fourth RUs RU1 to RU4.

As described above, at least one RU may be variously arranged in a frequency domain of a data field.

<FIG> is a view illustrating a structure of a trigger frame. For example, when a UL transmission is to be performed by one or more STAs to an AP, the AP may allocate different frequency resources for the one or more STAs as UL transmission resources based on OFDMA. Here, an example of the frequency resource is an RU, which may be indicated by a trigger frame transmitted by the AP to the STA before the UL transmission.

Therefore, to transmit the HE TB PPDU of <FIG> or EHT TB PPDU of <FIG>, a trigger frame as illustrated in <FIG> is first transmitted to the STA. The trigger frame may set uplink bandwidth and allocate the RU for UL multiple-user transmission. The trigger frame may be formed of a MAC (media access control) frame and may be included in a PPDU.

The trigger frame may be transmitted through the PPDU illustrated in <FIG> or a PPDU specially designed for the corresponding trigger frame. For example, when the trigger frame is transmitted through the PPDU illustrated in <FIG>, the trigger frame may be included in the data field.

As illustrated in <FIG>, a trigger frame may include a frame control field <NUM> (<NUM> octets), a duration field <NUM> (<NUM> octets), an RA (recipient address) field <NUM> (<NUM> octets), a TA (transmitting address) field <NUM> (<NUM> octets), a common information field <NUM> (no less than <NUM> octets), individual user information fields <NUM>-<NUM> to <NUM>-N (N is a natural number of <NUM> or more, and each information field is <NUM> or more octets), a padding field <NUM>, and a frame check sequence (FCS) field <NUM> (no less than <NUM> octets).

The frame control field <NUM> may include information on a version of a MAC protocol and other additional control information items. The duration field <NUM> may include time information for setting a network allocation vector (NAV) or information on an identifier (e.g., an association ID (AID)) of a terminal. The RA field <NUM> may include address information of the receiving device of the corresponding trigger frame and may be omitted when unnecessary. The TA field <NUM> may include address information of a transmitting device transmitting the corresponding trigger frame.

In the TA field <NUM>, a field indicating a length of an L-SIG field of a UL PPDU transmitted to the corresponding trigger frame or information controlling a content of an SIG-A field (that is, the HE-SIG-A field) of the UL PPDU transmitted to the corresponding trigger frame may be included. In addition, in the TA field <NUM>, as common control information, information on a length of a CP of the UL PPDU transmitted to the corresponding trigger frame or information on a length of an LTF field may be included.

The common information field <NUM> may include common information for receiving devices (for example, STA) receiving the corresponding trigger frame. The trigger frame may include the individual user information fields <NUM>-<NUM> to <NUM>-N (N is a natural number of no less than <NUM>) corresponding to the number of receiving devices receiving the trigger frame. For reference, the individual user information fields may be referred to as "user info list field". The trigger frame may include the padding field <NUM> and the FCS field <NUM>.

In other examples, some fields of the trigger frame may be omitted and other fields may be added. Further, a length of each field may be different from those illustrated.

An embodiment of the inventive concept relates to a method and apparatus for supporting MU communication using OFDMA. APs may allocate at least one RU for at least one of a plurality of receiving devices (e.g., STAs) through the OFDMA in an extended bandwidth. A method and apparatus for providing a trigger frame including information about an uplink bandwidth and at least one RU allocated the receiving device will be described later. In addition, a method and apparatus for identifying the uplink bandwidth and the allocated at least one RU from the trigger frame will be described. For example, as described later with reference to <FIG>, the AP may allocate at least one RU to at least one STA, generate a trigger frame for uplink transmission, and transmit the generated trigger frame to the at least one STA. The STA may receive the trigger frame from the AP, identify at least one RU allocated to the STA for uplink OFDMA, transmit data, e.g., a PPDU, to the AP based on the identified at least one RU. However, an embodiment of the inventive concept may be applied to a case where the STA transmits data to another STA and a case where the AP transmits data to the STA. In addition, an embodiment of the inventive concept may be applied to a circumstance supporting a single RU as well as downlink OFDMA and uplink OFDMA. Information about uplink bandwidth and RU allocated to the receiving device may be provided to the receiving device by the common info field <NUM> and the user info field of the trigger frame. Hereinafter, the common info field <NUM> and the user info field will be described with reference to <FIG>, <FIG> and <FIG>.

<FIG> is a diagram illustrating an example of a common information field, which contains information commonly applicable to multiple STAs. <FIG> and <FIG> are diagrams illustrating respective examples of a user information field.

Referring to <FIG>, the common information field may include a sequence of subfields from a first subfield <NUM> to a last subfield <NUM>. A STA may set a value of an uplink bandwidth subfield 420_1 among the plurality of subfields included in the common information field, and the STA may identify an uplink bandwidth based on the value of the uplink bandwidth subfield 420_1. The uplink bandwidth subfield 420_1 may have a length L1 for defining various uplink bandwidths. For example, a length L1 of the uplink bandwidth subfield 420_1 in HE may be <NUM> bits to indicate one of <NUM>, <NUM>, <NUM>, and <NUM>. In EHT, the length L1 of the uplink bandwidth subfield 420_1 may be at least <NUM> bits to indicate one of four bandwidths supported by the HE as well as an extended bandwidth, e.g., bandwidths up to <NUM>. Herein, the uplink bandwidth may be simply referred to as a bandwidth unless otherwise stated. In other examples, the common information field includes a field(s) not shown in <FIG>, and/or at least one field shown in <FIG> may be omitted from the common information field.

Referring to <FIG>, a first example of a user information field may include subfields such as an AID12 field 425_1a and an RU allocation subfield 425_2a. To specify the STA, an AP may set a value of the AID12 field 425_1a, and the STA may identify that the user information field is the user information field of the STA based on the value of the AID12 field 425_1a. In addition, to define at least one allocated RU, the AP may set a value of the RU allocation subfield 425_2a, and the STA may identify the at least one RU, which is allocated to the STA, based on the value of the RU allocation subfield 425_2a.

The RU allocation subfield 425_2a may have a length L2a for defining various RU allocations. For example, the length L2a of the RU allocation subfield 425_2a in the HE may be <NUM> bits to indicate a single RU allocable to the STA within a bandwidth of up to <NUM>. However, in EHT, the RU allocation subfield 425_2a may indicate not only the single RU allocable to the STA within the bandwidth of up to <NUM>, but also a multi-RU, and accordingly, a length of an RU allocation subfield 426_2a may be longer than at least <NUM> bits. The RU allocation subfield 425_2a for EHT may have a length of <NUM> bits, as will be described later with reference to <FIG>.

Referring to <FIG>, the user information field may include a plurality of subfields including an AID12 field 425_1b and an RU allocation subfield 425_2b. In addition, the user information field may further include a PS160 subfield 425_3 indicating a primary subband or a secondary subband, as shown in <FIG>. Although the PS160 subfield 425_3 is shown in <FIG> to correspond to a reserved area (e.g., B39) of the user information field of <FIG>, in other examples, the PS160 subfield 425_3 may be disposed in a different position from that shown in <FIG>.

As will be described later with reference to <FIG>, the PS160 subfield 425_3 may be used to define various RU allocations together with the RU allocation subfield 425_2b, and accordingly, a length L2b of the RU allocation subfield 425_2b may be shorter than the length L2a of <FIG>. For example, the length L2b of the RU allocation subfield 425_2b may be <NUM> bits. To define the at least one allocated RU, the AP may set values of the RU allocation subfield 425_2b and the PS160 subfield 425_3, and the STA may identify the at least one RU, which is allocated to the STA, based on the values of the RU allocation subfield 425_2b and the PS160 subfield 425_3. <FIG> is a message flow diagram illustrating a method of communication based on an extended bandwidth and a multi-RU according to an embodiment. <FIG> shows examples of operations of an AP <NUM> and a STA <NUM> in communication with each other. The AP <NUM> may communicate with at least one STA including the STA <NUM> included in a coverage area.

Referring to <FIG>, in operation S10, the AP <NUM> may generate an uplink bandwidth field. For example, the AP <NUM> may determine a bandwidth to be used by at least one STA including the STA <NUM> in uplink transmission. As described above with reference to <FIG>, in EHT, the uplink bandwidth field may have a length of at least <NUM> bits, and the AP <NUM> may determine a bandwidth of one of <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, and set the uplink bandwidth field to a value corresponding to the determined bandwidth.

In operation S20, the AP <NUM> may allocate at least one RU to the at least one STA. For example, the AP <NUM> may allocate a single RU to the STA <NUM> or may allocate a multi-RU to the STA <NUM>. For EHT, AP <NUM> may allocate a single RU to the STA <NUM> in the same way as is done in HE. Examples in which the AP <NUM> allocates a multi-RU to the STA <NUM> in a given bandwidth in EHT will be described later with reference to <FIG>.

In operation S30, the AP <NUM> may generate at least one subfield. For example, the AP <NUM> may generate at least one subfield included in a trigger frame based on the at least one RU allocated in operation S20. As described above with reference to <FIG>, an RU allocation subfield in EHT may have a length of at least <NUM> bits, and in operation S30, the AP <NUM> may set the RU allocation subfield as a value corresponding to the allocated at least one RU. In other examples, as described above with reference to <FIG>, the RU allocation subfield in EHT may have a length of <NUM> bits, the user information field may include a PS <NUM> subfield, and in operation S30, the AP <NUM> may set the RU allocation subfield and the PS160 subfield as values corresponding to the at least one allocated RU. An example of operation S30 will be described later with reference to <FIG>.

In operation S40, the AP <NUM> may generate a trigger frame and a PPDU. For example, the AP <NUM> may generate a common information field including the uplink bandwidth field generated in operation S <NUM> and a user information field including the at least one subfield generated in operation S30. The AP <NUM> may generate the trigger frame including the common information field and the user information field, and may generate the PPDU including the trigger frame.

In operation S50, the AP <NUM> may transmit the PPDU, and the STA <NUM> may receive the PPDU. In operation S60, the STA <NUM> may extract the trigger frame. The STA <NUM> may extract the trigger frame from the PPDU received in operation S50.

In operation S70, the STA <NUM> may extract the uplink bandwidth field and the at least one subfield. The STA <NUM> may extract the common information field and the user information field from the trigger frame extracted in operation S60. The STA <NUM> may extract the uplink bandwidth field having a length of at least <NUM> bits from the common information field, identify a user information field of the STA <NUM> based on an AID12 field, and extract the at least one subfield from the identified user information field.

In operation S80, the STA <NUM> may identify the at least one RU. The STA <NUM> may identify the bandwidth based on the uplink bandwidth field extracted in operation S70, and identify the at least one RU, which is allocated to the STA <NUM>, based on the identified bandwidth and the at least one subfield extracted in operation S70. An example of operation S80 will be described later with reference to <FIG>.

In operation S90, the STA <NUM> may transmit the PPDU, and the AP <NUM> may receive the PPDU. The STA <NUM> may perform uplink transmission on the at least one RU identified in operation S80 and may transmit the PPDU to the STA <NUM>. The AP <NUM> may receive the PPDU on the at least one RU allocated to the STA <NUM> within the bandwidth.

<FIG> shows small-size multi-RUs allocable to a STA in an OFDMA <NUM> EHT PPDU according to an embodiment. Specifically, the table of <FIG> shows indexes and combinations of the small-size multi-RUs allocable in a bandwidth of <NUM>. As described later with reference to <FIG> and <FIG>, values of RU allocation subfields may increase in the order of the indexes shown in <FIG>. In <FIG>, the indexes of a single RU may correspond to indexes shown in <FIG>.

Referring to <FIG>, the multi-RUs including a <NUM>-tone RU and a <NUM>-tone RU may have three different combinations, and may be indexed as first to third multi-RUs MRU1 to MRU3. As shown in <FIG>, the first multi-RU MRU1 may include a second <NUM>-tone RU and a second <NUM>-tone RU, the second multi-RU MRU2 may include a second <NUM>-tone RU and a fifth <NUM>-tone RU, and the third multi-RU MRU3 may include a third <NUM>-tone RU and an eighth <NUM>-tone RU.

A multi-RU including a <NUM>-tone RU and a <NUM>-tone RU may have two different combinations, and may be indexed as the first and second multi-RUs MRU1 and MRU2. As shown in <FIG>, the first multi-RU MRU1 may include a first <NUM>-tone RU and a fifth <NUM>-tone RU, and the second multi-RU MRU2 may include a second <NUM>-tone RU and the fifth <NUM>-tone RU.

<FIG> shows small-size multi-RUs allocable to a STA in an OFDMA <NUM> EHT PPDU according to an embodiment. Specifically, the table of <FIG> shows indexes and combinations of the small-size multi-RUs allocable in a bandwidth of <NUM>. In some embodiments, as described later with reference to <FIG> and <FIG>, values of RU allocation subfields may increase in the order of the indexes illustrated in <FIG>. In <FIG>, the indexes of a single RU may correspond to the indices shown in <FIG>.

Referring to <FIG>, the multi-RUs including a <NUM>-tone RU and a <NUM>-tone RU may have six different combinations, and may be indexed as first to sixth multi-RUs MRU1 to MRU6. As shown in <FIG>, the first multi-RU MRU1 may include a second <NUM>-tone RU and a second <NUM>-tone RU, the second multi-RU MRU2 may include a second <NUM>-tone RU and a fifth <NUM>-tone RU, the third multi-RU MRU3 may include a third <NUM>-tone RU and an eighth <NUM>-tone RU, the fourth multi-RU MRU4 may include a sixth <NUM>-tone RU and an 11th <NUM>-tone RU, the fifth multi-RU MRU5 may include a sixth <NUM>-tone RU and a 14th <NUM>-tone RU, and the sixth multi-RU MRU6 may include a 7th <NUM>-tone RU and a 17th <NUM>-tone RU.

A multi-RU including a <NUM>-tone RU and a <NUM>-tone RU may have four different combinations, and may be indexed as the first to fourth multi-RUs MRU1 to MRU4. As shown in <FIG>, the first multi-RU MRU1 may include a first <NUM>-tone RU and a fifth <NUM>-tone RU, the second multi-RU MRU2 may include a second <NUM>-tone RU and the fifth <NUM>-tone RU, the third multi-RU MRU3 may include a third <NUM>-tone RU and a 14th <NUM>-tone RU, and the fourth multi-RU MRU4 may include a fourth <NUM>-tone RU and the 14th <NUM>-tone RU.

<FIG> shows small-size multi-RUs allocable to a STA in an OFDMA <NUM> EHT PPDU according to an embodiment. Specifically, the table of <FIG> shows indexes and combinations of the small-size multi-RUs allocable in a bandwidth of <NUM>. In some embodiments, as described later with reference to <FIG> and <FIG>, values of RU allocation subfields may increase in the order of the indexes shown in <FIG>. In <FIG>, the indexes of a single RU may correspond to indices shown in <FIG>.

Referring to <FIG>, the multi-RUs including a <NUM>-tone RU and a <NUM>-tone RU may have <NUM> different combinations, and may be indexed as first to twelfth multi-RUs MRU1 to MRU12. As shown in <FIG>, the first multi-RU MRU1 may include a second <NUM>-tone RU and a second <NUM>-tone RU, the second multi-RU MRU2 may include the second <NUM>-tone RU and a fifth <NUM>-tone RU, the third multi-RU MRU3 may include a third <NUM>-tone RU and an eighth <NUM>-tone RU, the fourth multi-RU MRU4 may include a sixth <NUM>-tone RU and an 11th <NUM>-tone RU, the fifth multi-RU MRU5 may include the sixth <NUM>-tone RU and a 14th <NUM>-tone RU, and the sixth multi-RU MRU6 may include a 7th <NUM>-tone RU and a 17th <NUM>-tone RU. In addition, the seventh multi-RU MRU7 may include a 10th <NUM>-tone RU and a 21st <NUM>-tone RU, the eighth multi-RU MRU8 may include the 10th <NUM>-tone RU and a 24th <NUM>-tone RU, the ninth multi-RU MRU9 may include an 11th <NUM>-tone RU and a 27th <NUM>-tone RU, the 10th multi-RU MRU10 may include a 14th <NUM>-tone RU and a 30th <NUM>-tone RU, the eleventh multi-RU MRU11 may include the 14th <NUM>-tone RU and a 33rd <NUM>-tone RU, and the 12th multi-RU MRU6 may include a 15th <NUM>-tone RU and a 36th <NUM>-tone RU.

A multi-RU including a <NUM>-tone RU and a <NUM>-tone RU may have eight different combinations, and may be indexed as the first to eighth multi-RUs MRU1 to MRU8. As shown in <FIG>, the first multi-RU MRU1 may include a first <NUM>-tone RU and a fifth <NUM>-tone RU, the second multi-RU MRU2 may include a second <NUM>-tone RU and the fifth <NUM>-tone RU, the third multi-RU MRU3 may include a third <NUM>-tone RU and a 14th <NUM>-tone RU, and the fourth multi-RU MRU4 may include a fourth <NUM>-tone RU and the 14th <NUM>-tone RU. In addition, the fifth multi-RU MRU5 may include a fifth <NUM>-tone RU and a 24th <NUM>-tone RU, the sixth multi-RU MRU6 may include a sixth <NUM>-tone RU and the 24th <NUM>-tone RU, the seventh multi-RU MRU7 may include a seventh <NUM>-tone RU and a 33rd <NUM>-tone RU, and the eighth multi-RU MRU8 may include an eighth <NUM>-tone RU and the 33rd <NUM>-tone RU.

Like the multi-RUs including a <NUM>-tone RU and a <NUM>-tone RU and the multi-RUs including a <NUM>-tone RU and a <NUM>-tone RU, a multi-RU including only small-size RUs (i.e., a <NUM>-tone RU, a <NUM>-tone RU, and a <NUM>-tone RU) may be referred to as a small-size multi-RU. In some embodiments, only some of the small-size multi-RUs may be used in a bandwidth equal to or greater than <NUM>. For example, as shown in <FIG>, some (i.e., MRU1, MRU6, MRU7, and MRU12) of the multi-RUs including a <NUM>-tone RU and a <NUM>-tone RU and some (i.e., MRU2, MRU3, MRU6, and MRU7) of the multi-RUs including a <NUM>-tone RU and a <NUM>-tone RU may not be used in the bandwidth equal to or greater than <NUM>.

<FIG> and <FIG> show small-size multi-RUs allocable to a STA in an OFDMA <NUM> EHT PPDU according to an embodiment. Specifically, the tables of <FIG> and <FIG> show indexes and combinations of the small-size multi-RUs allocable in a bandwidth of <NUM>. In some embodiments, as described later with reference to <FIG> and <FIG>, values of RU allocation subfields may increase in the order of the indexes shown in <FIG> and <FIG>.

Referring to <FIG>, the multi-RUs including a <NUM>-tone RU and a <NUM>-tone RU may have <NUM> different combinations, and may be indexed as first to 24th multi-RUs MRU1 to MRU24. Referring to <FIG>, the multi-RU including a <NUM>-tone RU and a <NUM>-tone RU may have <NUM> different combinations, and may be indexed as the first to sixteenth multi-RUs MRU1 to MRU16.

<FIG>, <FIG>, and <FIG> show small-size multi-RUs allocable to a STA in an OFDMA <NUM> EHT PPDU according to an embodiment. Specifically, the tables of <FIG>, <FIG>, and <FIG> show indexes and combinations of small-size multi-RUs allocable in a bandwidth of <NUM>. In some embodiments, as described later with reference to <FIG> and <FIG>, values of RU allocation subfields may increase in the order of the indexes illustrated in <FIG>, <FIG>, and <FIG>.

Referring to <FIG> and <FIG>, the multi-RU including a <NUM>-tone RU and a <NUM>-tone RU may have <NUM> different combinations, and may be indexed as first to 48th multi-RUs MRU1 to MRU48. Referring to <FIG>, the multi-RU including a <NUM>-tone RU and a <NUM>-tone RU may have <NUM> different combinations, and may be indexed as the first to 32nd multi-RUs MRU1 to MRU32.

<FIG> shows large-size multi-RUs allocable to a STA in an OFDMA <NUM> EHT PPDU according to an embodiment. Specifically, the table of <FIG> shows indexes and combinations of the large-size multi-RUs allocable in a bandwidth of <NUM>. In some embodiments, as described later with reference to <FIG> and <FIG>, values of RU allocation subfields may increase in the order of the indexes shown in <FIG>.

Referring to <FIG>, the multi-RUs including a <NUM>-tone RU and a <NUM>-tone RU may have four different combinations, and may be indexed as the first to fourth multi-RUs MRU1 to MRU4.

<FIG> shows large-size multi-RUs allocable to a STA in an OFDMA <NUM> EHT PPDU according to an embodiment. Specifically, the table of <FIG> shows indexes and combinations of large-size multi-RUs allocable in a bandwidth of <NUM>. In some embodiments, as described later with reference to <FIG> and <FIG>, values of RU allocation subfields may increase in the order of the indexes illustrated in <FIG>.

Referring to <FIG>, the multi-RU including a <NUM>-tone RU and a <NUM>-tone RU may have eight different combinations and may be indexed as the first to eighth multi-RUs MRU1 to MRU8. In a bandwidth of <NUM>, four <NUM>-tone RUs may be sequentially arranged, and eight <NUM>-tone RUs may be sequentially arranged. As shown in <FIG>, the first to eighth multi-RUs may respectively correspond to combinations of sequentially unallocated eight <NUM>-tone RUs.

The multi-RUs including a <NUM>-tone RU and a <NUM>-tone RU may have four different combinations, and may be indexed as the first to fourth multi-RUs MRU1 to MRU4. In a bandwidth of <NUM>, two <NUM>-tone RUs may be sequentially arranged, and four <NUM>-tone RUs may be sequentially arranged. As shown in <FIG>, the first to fourth multi-RUs MRU1 to MRU4 may respectively correspond to combinations of sequentially unallocated four <NUM>-tone RUs.

The multi-RUs including a <NUM>-tone RU, a <NUM>-tone RU, and a <NUM>-tone RU may have <NUM> different combinations, and may be indexed as the first to eighth multi-RUs MRU1 to MRU8. In a bandwidth of <NUM>, two <NUM>-tone RUs may be sequentially arranged, four <NUM>-tone RUs may be sequentially arranged, and eight <NUM>-tone RUs may be sequentially arranged. As shown in <FIG>, the first to eighth multi-RUs MRU1 to MRU8 may respectively correspond to combinations of sequentially unallocated eight <NUM>-tone RUs.

<FIG>, <FIG>, and <FIG> show large-size multi-RUs allocable to a STA in an OFDMA <NUM> EHT PPDU according to an embodiment. Specifically, <FIG>, <FIG>, and <FIG> show separate tables for illustration purposes, and the tables of <FIG>, <FIG> and <FIG> show indexes and combinations of the large-size multi-RUs allocable in a bandwidth of <NUM>. In some embodiments, as described later with reference to <FIG> and <FIG>, values of RU allocation subfields may increase in the order of the indexes shown in <FIG>, <FIG>, and <FIG>.

Referring to <FIG>, multi-RUs including a <NUM>-tone RU and a <NUM>-tone RU may have <NUM> different combinations, and may be indexed as the first to sixteenth multi-RUs MRU1 to MRU16. In a bandwidth of <NUM>, eight <NUM>-tone RUs may be sequentially arranged, and sixteen <NUM>-tone RUs may be sequentially arranged. As shown in <FIG>, the first to sixteenth multi-RUs may respectively correspond to combinations of sequentially unallocated sixteen <NUM>-tone RUs.

The multi-RUs including a <NUM>-tone RU and a <NUM>-tone RU may have eight different combinations, and may be indexed as the first to eighth multi-RUs MRU1 to MRU8. In a bandwidth of <NUM>, four <NUM>-tone RUs may be sequentially arranged, and eight <NUM>-tone RUs may be sequentially arranged. As shown in <FIG>, the first to eighth multi-RUs MRU1 to MRU8 may respectively correspond to combinations of sequentially unallocated eight <NUM>-tone RUs.

Referring to <FIG>, multi-RUs including a <NUM>-tone RU, a <NUM>-tone RU, and a <NUM>-tone RU may have <NUM> different combinations, and be indexed as the first to sixteenth multi-RUs MRU1 to MRU16. In a bandwidth of <NUM>, four <NUM>-tone RUs may be sequentially arranged, eight <NUM>-tone RUs may be sequentially arranged, and sixteen <NUM>-tone RUs may be sequentially arranged. As shown in <FIG>, the first to sixteenth multi-RUs MRU1 to MRU16 may respectively correspond to combinations of sequentially unallocated sixteen <NUM>-tone RUs.

A multi-RU including two <NUM>-tone RUs and a <NUM>-tone RU may have <NUM> different combinations, and may be indexed as the first to twelfth multi-RUs MRU1 to MRU12. In a bandwidth of <NUM>, the first to fourth <NUM>-tone RUs may be sequentially arranged and the first to eighth <NUM>-tone RUs may be sequentially arranged. As shown in <FIG>, the first to fifth multi-RUs MRU1 to MRU6 may respectively correspond to combinations of the sequentially unallocated first to sixth <NUM>-tone RUs while the fourth <NUM>-tone RU is not allocated. In addition, the seventh to twelfth multi-RUs MRU7 to MRU12 may respectively correspond to combinations of the sequentially unallocated third to eighth <NUM>-tone RUs while the first <NUM>-tone RU is not allocated.

Referring to <FIG>, a multi-RU including three <NUM>-tone RUs may have four different combinations, and may be indexed as the first to fourth multi-RUs MRU1 to MRU4. In a <NUM> bandwidth, four <NUM>-tone RUs may be sequentially arranged, and as shown in <FIG>, the first to fourth multi-RUs MRU1 to MRU4 may respectively correspond to combinations of sequentially unallocated four <NUM>-tone RUs.

A multi-RU including three <NUM>-tone RUs and a <NUM>-tone RU may have <NUM> different combinations, and may be indexed as the first to eighth multi-RUs MRU1 to MRU8. In a <NUM> bandwidth, four <NUM>-tone RUs may be sequentially arranged and eight <NUM>-tone RUs may be sequentially arranged. As shown in <FIG>, the first to eighth multi-RUs MRU1 to MRU8 may respectively correspond to combinations of sequentially unallocated eight <NUM>-tone RUs.

In EHT, a user information field may define not only single RUs of HE but also the multi-RUs described above with reference to <FIG>. Hereinafter, examples of the user information field defining single RUs and multi-RUs in an extended bandwidth of EHT will be described.

<FIG> is a flowchart illustrating a method of communication based on an extended bandwidth and multi-RUs according to an embodiment. Specifically, <FIG> shows an example of operation S30 of <FIG>. As described above with reference to <FIG>, the AP <NUM> may generate at least one subfield in operation S30' of <FIG>. Nine bits or more included in a user information field may be used to define at least one RU allocated in EHT. As described above with reference to <FIG>, an RU allocation subfield may have a length of <NUM> bits, and the <NUM> bits may include a first group of <NUM> bits and a second group of <NUM> bits to be described later. In other examples, as described above with reference to <FIG>, the RU allocation subfield may have a length of <NUM> bits, and the <NUM> bits may include at least <NUM> bits to be described later. The group of at least <NUM> bits to be described later may include one bit of the RU allocation subfield and one bit of a PS160 subfield. As shown in <FIG>, operation S30' may include a plurality of operations S31 to S37, which will be described with reference to <FIG>.

Referring to <FIG>, in operation S31, the AP <NUM> sets "K" bits, where the K is at least <NUM> and the K bits are associated with at least one RU. For example, the AP <NUM> may set K bits of the RU allocation subfield in association with the at least one RU allocated to the STA <NUM> in operation S20 of <FIG>. The at least one RU may be defined in a subband with only the K bits, or may be defined based on at least one bit of the M bits (where M is at least two) described later, as well as the K bits. The M bits of the user information field may be set in operations (i.e., S32 to S37) following operation S31.

In operation S32, the AP <NUM> determines whether the bandwidth corresponds to two subbands. Herein, a subband may refer to a minimum frequency band including the at least one RU allocated to the STA <NUM>, that is, a frequency band including a channel, and may have a width of e.g., <NUM>, <NUM>, or <NUM>. Herein, the subband may be simply referred to in terms of its width. Accordingly, the cases where the bandwidth corresponds to two subbands in EHT may include a case where the subband is <NUM> in a bandwidth of <NUM> and the case where the subband is <NUM> in a bandwidth of <NUM>. When the bandwidth includes a plurality of subbands, the plurality of subbands may include a primary subband and at least one secondary subband. Management and control information may be transmitted in a primary subband but may not be transmitted in a secondary subband.

When the bandwidth corresponds to two subbands, in operation S33, the AP <NUM> sets one bit as a value defining a subband including at least one RU, and in operation S34, the AP <NUM> sets another bit associated with the at least one RU. That is, one of the M=<NUM> bits of the user information field may represent one of the two subbands, and the other of the M=<NUM> bits may define the at least one RU along with the K bits. (Since the K bits and the M bits collectively define the at least one RU, each of the K bits and the M bits are associated with the at least one RU).

When the bandwidth does not correspond to two subbands, in operation S35, the AP <NUM> determines whether the bandwidth corresponds to four or more subbands. For example, cases where the bandwidth corresponds to four subbands in EHT may include a case where the subband is <NUM> in a bandwidth of <NUM>.

When the bandwidth includes four or more subbands, in operation S36, the AP <NUM> sets the M bits as a value defining a subband including at least one RU. For example, the value may be a decimal value defined by the binary sequence of the M bits. Accordingly, the M bits of the user information field may define one of four or more subbands including at least one RU defined in part by the K bits set in operation S31.

When the bandwidth does not include four or more subbands, e.g., when the bandwidth includes a single subband, in operation S37, the AP <NUM> may sets the M bits associated with the at least one RU. For example, the cases where the bandwidth includes the single subband in EHT includes the case where the bandwidth is <NUM>, <NUM>, or <NUM>, the case where the subband is <NUM> in the bandwidth of <NUM>, and the case where the subband is <NUM> in the bandwidth of <NUM>.

<FIG> is a flowchart illustrating a method of communication based on an extended bandwidth and multi-RUs according to an embodiment. Specifically, <FIG> shows an example of operation S80 of <FIG>. As described above with reference to <FIG>, in operation S80' of <FIG>, the STA <NUM> may identify at least one RU allocated to the STA <NUM>. In some embodiments, as described above with reference to <FIG>, an RU allocation subfield may have a length of <NUM> bits, and <NUM> bits may include at least <NUM> bits and at least <NUM> bits described below. In addition, in some embodiments, as described above with reference to <FIG>, the RU allocation subfield may have a length of <NUM> bits, and the <NUM> bits may include at least <NUM> bits to be described later. The at least <NUM> bits to be described later may include one bit of the RU allocation subfield and one bit of the PS160 subfield. As shown in <FIG>, operation S80' may include a plurality of operations S81 to S87. Hereinafter, a description of <FIG> that is redundant with the description of <FIG> will be omitted, and <FIG> will be described with reference to <FIG>.

Referring to <FIG>, in operation S81, the STA <NUM> may identify at least one RU based on K (at least <NUM>) bits. The STA <NUM> may identify at least one RU defined in a subband with only the K bits, and may identify at least one RU based on at least one bit of the M (at least <NUM>) bits to be described later as well as the K bits. The K bits of the user information field may be analyzed in operations (i.e., S82 to S87) following operation S81.

In operation S82, the STA <NUM> may determine whether a bandwidth corresponds to two subbands. When the bandwidth corresponds to the two subbands, in operation S83, the STA <NUM> may identify the subband including the at least one RU based on one bit of M bits, and in operation S84 the STA <NUM> may identify the at least one RU based on the other bit(s) of the M bits. Hereafter, examples are described in which M equals two.

When the bandwidth does not correspond to the two subbands, in operation S85, the STA <NUM> may determine whether the bandwidth corresponds to four or more sub-bands. When the bandwidth includes four or more subbands, in operation S86, the STA <NUM> may identify a subband including the at least one RU based on the M bits. When the bandwidth does not include four or more subbands, the STA <NUM> may identify the at least one RU based on the M bits in operation S87.

<FIG> and <FIG> are diagrams illustrating examples of a user information field according to example embodiments. Specifically, <FIG> illustrates an example of an RU allocation subfield included in a user information field, and <FIG> illustrates an example of a user information field including the RU allocation subfield and a PS160 subfield.

Referring to <FIG>, the RU allocation subfield may include <NUM> bits, that is, first to ninth bits X0 to X8. The third to ninth bits X2 to X8 may correspond to at least <NUM> bits in <FIG> and <FIG>, and the first and second bits X0 and X1 may correspond to at least <NUM> bits in <FIG> and <FIG>. In some embodiments, the at least <NUM> bits of <FIG> and <FIG> may include a least significant bit (LSB) of the RU allocation subfield as shown in <FIG>, and may include a most significant bit (MSB) or both the LSB and the MSB differently from that shown in <FIG>.

Referring to <FIG>, as described above with reference to <FIG> and <FIG>, when a bandwidth includes a plurality of subbands, the first bit X0 and/or the second bit X1 may define one of the plurality of subbands. As shown in a first table T1 of <FIG>, when the subband is <NUM> in a bandwidth of <NUM>, the second bit X1 may define a lower <NUM> or an upper <NUM>, and when the subband is <NUM> in a bandwidth of <NUM>, the first and second bits X0 and X1 may define one of lower <NUM> and upper <NUM> in the lower <NUM>, and lower <NUM> and upper <NUM> in the upper <NUM>. Accordingly, the second bit X1 of the RU allocation subfield defining at least one RU allocated to a primary <NUM> in a bandwidth of <NUM> may correspond to '<NUM>', and the second bit X1 of the RU allocation subfield defining at least one RU allocated to a secondary <NUM> may correspond to '<NUM>'.

A second table T2 of <FIG> represents values of the first and second bits X0 and X1 for indicating at least one RU allocated to each <NUM> according to a position of the primary <NUM> and/or the primary <NUM> in the bandwidth of <NUM>. In the bandwidth of <NUM>, the first bit X0 may be zero, and a third table T3 of <FIG> represents a value of the second bit X1 for indicating the at least one RU allocated to each <NUM> according to the position of the primary <NUM> in the bandwidth of <NUM>. In a bandwidth of <NUM> or less, the first bit X0 and the second bit X1 may be zero.

Referring to <FIG>, in some embodiments, the user information field may include an RU allocation subfield of <NUM> bits and a PS160 subfield of <NUM> bit. As shown in <FIG>, the RU allocation subfield may include first to eighth bits B0 to B7, and the PS160 subfield may include bits Bx. In some embodiments, the second to eighth bits B1 to B7 of the RU allocation subfield may correspond to at least <NUM> bits of <FIG> and <FIG>, and the first bit B0 of the RU allocation subfield and the bit Bx of the PS <NUM> subfield may correspond to at least <NUM> bits of <FIG> and <FIG>. In some embodiments, the first bit B0 of the RU allocation subfield may be an LSB of the RU allocation subfield as shown in <FIG>, or may be an MSB different from that shown in <FIG>.

Referring to <FIG>, as described above with reference to <FIG> and <FIG>, when a bandwidth includes a plurality of subbands, the first bit B0 of the RU allocation subfield and the bit Bx of the PS160 subfield may define one subband among a plurality of subbands. In some embodiments, the first bit B0 of the RU allocation subfield may indicate a primary <NUM> or a secondary <NUM> for a single RU and/or multi-RUs of <NUM> or less in the primary <NUM>. In addition, the first bit B0 of the RU allocation subfield may be used to index multi-RUs with respect to a single RU and/or multi-RUs greater than <NUM>. The bit Bx of the PS160 subfield may indicate a primary <NUM> or a secondary <NUM> with respect to a single RU and/or multi-RUs of <NUM> or less. In addition, the bit Bx of the PS160 subfield may be used to index multi-RUs with respect to a single RU and/or multi-RUs greater than <NUM>. Accordingly, the first bit X0 and the second bit X1 of <FIG> may be derived from the first bit B0 of the RU allocation subfield and the bit Bx of the PS <NUM> subfield according to conditions defined by a pseudo code (CD) of <FIG>.

A fourth table T4 of <FIG> represents values of the first bit X0 and the second bit X1 of <FIG> respectively calculated from the first bit B0 of the RU allocation subfield and the bit Bx of the PS <NUM> subfield according to the position of the primary <NUM> and/or the primary <NUM> in the bandwidth of <NUM>. For example, as shown in <FIG>, when the secondary <NUM>, the primary <NUM>, and the secondary <NUM> are sequentially arranged ([S80 P80 S <NUM>]), the first bit X0 of <FIG> may be same with the bit Bx of the PS160 subfield, and the second bit X1 of <FIG> may correspond to a negation (or a logical complement) of a logical sum (or an XOR operation result) of the first bit B0 of the RU allocation subfield and the bit Bx of the PS <NUM> subfield. In addition, a fifth table T5 of <FIG> represents values of the first bit X0 and the second bit X1 of <FIG> calculated from the first bit B0 of the RU allocation subfield and the bit Bx of the PS <NUM> subfield according to the position of the primary <NUM> in the bandwidth of <NUM>. The bit Bx of the PS <NUM> subfield may be zero in the bandwidth of <NUM>. In addition, the bit Bx of the PS <NUM> subfield and the first bit B0 of the RU allocation subfield may be zero in a bandwidth of <NUM> or less. Hereinafter, the example of <FIG> will be mainly described, but it is noted that embodiments may also be applied to the example of <FIG>.

<FIG> and <FIG> are diagrams illustrating an RU allocation subfield according to an embodiment. Specifically, <FIG> and <FIG> represent separate tables for illustration purposes, and the tables of <FIG> and <FIG> represent values of the RU allocation subfield and single RUs or multi-RUs corresponding to the values.

Referring to <FIG>, a small-size single RU, a small-size multi-RU, and multi-RUs including a <NUM>-tone RU and a <NUM>-tone RU may be included in subband of <NUM> or less. Accordingly, as illustrated in <FIG>, the first and second bits X0 and X1 of the RU allocation subband may define a channel position, that is, a subband to which at least one RU is allocated. To define the small-size single RU, a small-size multi-RU described above with reference to <FIG>, and multi-RUs including a <NUM>-tone RU and a <NUM>-tone RU, <NUM> bits of the RU allocation subband, that is, the third to ninth bits X2 to X8, may have values as shown in <FIG>.

An index of an RU may be calculated from the first and second bits X0 and X1. In some embodiments, as shown in <FIG>, a variable N may be calculated as "<NUM>*X0 + X1", and the RU index may be calculated from the variable N. For example, an index of a <NUM>-tone RU may correspond to a sum of "<NUM>*N" and an RU index of EHT, an index of a <NUM>-tone RU may correspond to a sum of "<NUM>*N" and the RU index of EHT, an index of a <NUM>-tone RU may correspond to a sum of "<NUM>*N" and the RU index of EHT, an index of a <NUM>-tone RU may correspond to a sum of "<NUM>*N" and the RU index of EHT, an index of a <NUM>-tone RU may correspond to a sum of "<NUM>*N" and the RU index of EHT, and an index of a <NUM>-tone RU may correspond to a sum of N and the RU index of EHT. An index of a multi-RU including two <NUM>-tone RUs may correspond to a sum of the first bit X0 and the RU index of EHT, an index of a multi-RU including four <NUM>-tone RUs may be <NUM>, an index of a multi-RU including a <NUM>-tone RU and a <NUM>-tone RU may correspond to a sum of "<NUM>*N" and the RU index of EHT, an index of a multi-RU including a <NUM>-tone RU and a <NUM>-tone RU may correspond to a sum of "<NUM>*N" and the RU index of EHT, and an index of a multi-RU including a <NUM>-tone RU and a <NUM>-tone RU may correspond to a sum of "<NUM>*N" and the RU index of EHT. Referring to <FIG>, to define a large-size multi-RU, except for the multi-RU including the <NUM>-tone RU and the <NUM>-tone RU, the first to ninth bits X0 to X8 of the RU allocation subband may have a value as shown in <FIG>. The index of the multi-RU of <FIG> may be calculated from the first bit X0. For example, an index of a multi-RU including the <NUM>-tone RU and the <NUM>-tone RU may correspond to a sum of "<NUM>*X0" and the RU index of EHT, and an index of a multi-RU including the <NUM>-tone RU, the <NUM>-tone RU and the <NUM>-tone RU may correspond to a sum of "<NUM>*X0" and the RU index of EHT. Indexes of the remaining multi-RUs may be same with the RU indexes of EHT.

Values of RU allocation subbands defining large-size multi-RUs, except for the multi-RUs including the <NUM>-tone RU and the <NUM>-tone RU, will be described later with reference to <FIG>.

In some embodiments, only some of the single RU and/or the multi-RU shown in <FIG> and <FIG> may be used for multi-user (MU) transmission. For example, MU-MIMO of EHT may be possible in a single RU and/or a multi-RU corresponding to <NUM> or more subcarriers. Accordingly, the AP may allocate at least one RU to a plurality of multiplexed STAs, and may generate the RU allocation subfield for MU transmission.

In some embodiments, the RU allocation subfield for MU transmission may have a structure similar to the RU allocation subfield for single user (SU) transmission. For example, the RU allocation subfield for MU transmission may include at least <NUM> bits representing a decimal value that sequentially increases according to values of the third to ninth bits X2 to X8 in cells hatched / shaded in <FIG> and cells shown in <FIG>. Accordingly, the AP may set the at least <NUM> bits of the RU allocation subfield based on the at least one RU for MU transmission, may set one bit of at least <NUM> bits to define one of the two subbands included in the bandwidth, and may set two bits of at least <NUM> bits to define one of four subbands included in the bandwidth. Accordingly, the RU allocation subfield for MU transmission may have a length of at least <NUM> bits.

The RU allocation subfield for MU transmission may be set independently from the RU allocation subfield for SU transmission. For example, the RU allocation subfield may have one of values for representing <NUM> single RUs, that is, sixteen <NUM>-tone RUs, eight <NUM>-tone RUs, and four <NUM>-tone RUs. In addition, the RU allocation subfield may have one of values for representing <NUM> multi-RUs, that is, two multi-RUs each including two <NUM>-tone RUs, a multi-RU including four <NUM>-tone RUs, <NUM> multi-RUs each including a <NUM>-tone RU and a <NUM>-tone RU, <NUM> multi-RUs each including a <NUM>-tone RU and a <NUM>-tone RU, <NUM> multi-RUs each including a <NUM>-tone RU, a <NUM>-tone RU and a <NUM>-tone RU, <NUM> multi-RUs each including two <NUM>-tone RUs and a <NUM>-tone RU, <NUM> multi-RUs each including three <NUM>-tone RUs, and <NUM> multi-RUs each including three <NUM>-tone RUs and a <NUM>-tone RU. Accordingly, the RU allocation subfield for MU transmission may have one of a total of <NUM> values, and to this end, may have a length of at least <NUM> bits.

<FIG> shows values of multi-RUs including a <NUM>-tone RU and a <NUM>-tone RU and an RU allocation subfield according to an embodiment. In this case, the multi-RUs including the <NUM>-tone RU and the <NUM>-tone RU may have four different combinations within a subband, e.g., <NUM>, as described above with reference to <FIG>. Accordingly, the first bit X0 among the first and second bits X0 and X1 of the RU allocation subfield may define a subband (e.g., <NUM>) including multi-RUs in a bandwidth of <NUM>, whereas the second bit X1 may define multi-RUs together with the third to ninth bits X2 to X8. In particular, as shown in <FIG>, the second and third bits X1 and X2 may represent locations of unallocated <NUM>-tone RUs in the subband (e.g., <NUM>). Accordingly, as described above with reference to <FIG> and <FIG>, to define multi-RUs indexed based on the location of the unallocated <NUM>-tone RU, the RU allocation subfield may have values shown in <FIG> and <FIG>. It is noted that herein, "unallocated" RUs may be "punctured" RUs, in which puncture frequencies of the RU are frequencies that are not used. Such puncturing of frequencies may be implemented to avoid interference with another AP that is using those frequencies in a communication with another STA.

<FIG> shows values of multi-RUs including a <NUM>-tone RU, a <NUM>-tone RU, and a <NUM>-tone RU and an RU allocation subfield according to an embodiment. Here, the multi-RUs including the <NUM>-tone RU, the <NUM>-tone RU, and the <NUM>-tone RU, as described above with reference to <FIG>, may have eight different combinations within a subband, e.g., <NUM>. Accordingly, the first bit X0 among the first and second bits X0 and X1 of the RU allocation subfield may define the subband (e.g., <NUM>) including multi-RUs in a bandwidth of <NUM>, and the second bit X1 may define multi-RUs together with the third to ninth bits X2 to X8. In particular, as shown in <FIG>, the second to fourth bits X1 to X3 may indicate a location of the unallocated <NUM>-tone RU in the subband (e.g., <NUM>). Accordingly, as described above with reference to <FIG> and <FIG>, to define multi-RUs indexed based on the location of the unallocated <NUM>-tone RU, the RU allocation subfield may have values shown in <FIG> and <FIG>. (As noted earlier, a punctured RU is an example of an unallocated RU).

<FIG> shows values of multi-RUs including two <NUM>-tone RUs and a <NUM>-tone RU and an RU allocation subfield according to an embodiment. In <FIG>, the multi-RU including the two <NUM>-tone RUs and the <NUM>-tone RU may have <NUM> different combinations within a subband, e.g., <NUM>, as described above with reference to <FIG>. Accordingly, the first and second bits X0 and X1 of the RU allocation subfield may define multi-RUs together with the third to ninth bits X2 to X8. As shown in <FIG>, the first bit X0 may represent a location of an unallocated <NUM>-tone RU in the subband (e.g., <NUM>), and the second to fourth bits X1 to X3 may represent a location of an unallocated <NUM>-tone RU. Accordingly, as described above with reference to <FIG>, to define multi-RUs indexed based on the locations of the unallocated <NUM>-tone RU and <NUM>-tone RU, the RU allocation subfield may have values shown in <FIG> and <FIG>.

<FIG> shows values of multi-RUs including three <NUM>-tone RUs and an RU allocation subfield according to an embodiment. Referring to <FIG>, the multi-RU including the three <NUM>-tone RUs may have four different combinations within a subband, that is, <NUM>, as described above with reference to <FIG>. Accordingly, the first and second bits X0 and X1 of the RU allocation subfield may define multi-RUs together with the third to ninth bits X2 to X8. In particular, as shown in <FIG>, the first and second bits X0 and X1 may represent locations of unallocated <NUM>-tone RUs in the subband (e.g., <NUM>). Accordingly, as described above with reference to <FIG>, to define the multi-RU indexed based on the locations of the unallocated <NUM>-tone RU, the RU allocation subfield may have values shown in <FIG> and <FIG>.

<FIG> shows values of multi-RUs including three <NUM>-tone RUs and a <NUM>-tone RU and an RU allocation subfield according to an embodiment. In this case, the multi-RU including the three <NUM>-tone RUs and a <NUM>-tone RU may have eight different combinations within a subband, that is, <NUM>, as described above with reference to <FIG>. Accordingly, the first and second bits X0 and X1 of the RU allocation subfield may define multi-RUs together with the third to ninth bits X2 to X8. As shown in <FIG>, the first to third bits X0 to X2 may represent locations of unallocated <NUM>-tone RUs in the subband (e.g., <NUM>). Accordingly, as described above with reference to <FIG>, to define the multi-RU indexed based on the locations of the unallocated <NUM>-tone RU, the RU allocation subfield may have values shown in <FIG> and <FIG>.

<FIG> is a diagram illustrating an RU allocation subfield according to an embodiment. In some embodiments, as shown in <FIG>, the RU allocation subfield may include <NUM> bits, e.g., the first to ninth bits X0 to X8. Compared with the example of <FIG>, the RU allocation subfield of <FIG> may include the first bit X0 for defining one of two subbands, that is, a lower <NUM> and an upper <NUM>, in a bandwidth of <NUM>, and may include the second to ninth bits X1 to X8 for defining at least one RU. Accordingly, based on at least one RU allocated to a STA, that is, a single RU or the multi-RUs described above with reference to <FIG>, an AP may set at least <NUM> bits, e.g., the second to ninth bits X1 to X8. In addition, the AP may set the first bit X0 to a value representing one of a lower <NUM> and an upper <NUM> when the subband is <NUM> in a bandwidth of.

Claim 1:
A method of communicating, by a first device (<NUM>, <NUM>), with at least one second device (<NUM>, <NUM>, <NUM>, <NUM>) in a wireless local area network (<NUM>), hereinafter referred to as WLAN, system, the method comprising:
allocating a multiple resource unit, hereinafter referred to as multi-RU, within a bandwidth to one of the at least one second device (<NUM>, <NUM>, <NUM>, <NUM>), the multi-RU including two or more single RU (S20);
generating at least one subfield defining the multi-RU (S30);
generating a trigger frame comprising a user information field comprising the at least one subfield (S40); and
transmitting a physical protocol layer data unit, hereinafter referred to as PPDU, comprising the trigger frame to the at least one second device (S50),
wherein the generating the at least one subfield comprises:
setting at least seven bits indicating the multi-RU;
when the bandwidth corresponds to two subbands, setting (S33) a first bit as a value defining a subband that includes the multi-RU and setting (S34) a second bit associated with the multi-RU;
and when the bandwidth includes at least four subbands, setting (S36) at least two bits including the first and second bits as a value defining a subband that includes the multi-RU.