Communication devices, communication methods, and programs

Abstract

This technology provides proper communication when Dual Carrier Modulation (DCM) is applied to a Distributed-tone Resource Unit (DRU). [Solution] A communication device compliant with the IEEE 802.11 standard series has a transmission means that transmits a frame that includes information requesting the application of Dual Carrier Modulation (DCM) to a Distributed-tone Resource Unit (DRU) and requests data transmission to another communication device.

Description

Technical Field

[0001] The present disclosure relates to a communication device, a communication method, and a program.

Background Art

[0002] With the increase in the amount of data communicated in recent years, the development of communication technologies such as wireless LAN (Local Area Network) has been promoted. As the main communication standards for wireless LAN, the IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard series is known. The IEEE 802.11 standard series includes standards such as IEEE 802.11a / b / g / n / ac / ax / be. In order to further improve communication reliability, the development of the IEEE 802.11bn standard is underway as a successor standard to the IEEE 802.11be standard.

[0003] In the IEEE 802.11 WG (Working Group) that formulates the IEEE 802.11bn standard, the goals and scope of study of this standard are determined in the UHR SG, and the detailed technical content to be included in this standard is scheduled to be defined in the TGbn. Note that UHR SG is an abbreviation for Ultra High Reliability Study Group. Also, TGbn is an abbreviation for Task Group bn.

[0004] The name UHR was provided for convenience based on the goals to be achieved by the successor standard and the features that are the highlights of the standard, and it can be another name when the standard formulation is completed. Similarly, the name IEEE 802.11bn can be another name when the standard formulation is completed. On the other hand, this specification and the appended claims are essentially applicable to all successor standards that are successor standards to the 802.11be standard.

[0005] Patent Document 1 discloses communication using OFDMA (Orthogonal Frequency Division Multiple Access) (also called OFDMA communication). In OFDMA communication, an access point (AP) allocates a frequency domain (subchannel) to a station (STA) on a resource unit (RU) basis.

[0006] Here, RU is a channel division unit used for communication, and an RU includes multiple subcarriers (also called subcarriers or tones). The method of division into RUs (size and range of RUs) is defined for channels of each frequency bandwidth: 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz. When the multiple subcarriers constituting a single RU are consecutive in the frequency domain, that RU is also called an RRU (Regular RU). In this specification and drawings, RRU may also be written as rRU.

[0007] Patent Document 2 discloses a communication method using a DRU that uses distributed subcarriers as subcarriers constituting a single RU. DRU is an abbreviation for Distributed-tone Resource Unit. In this specification and drawings, DRU may also be written as dRU.

[0008] RRU consists of consecutive subcarriers. In contrast, DRU consists of subcarriers distributed across a wide frequency band. This reduces the transmit power density, making it possible to increase transmit power even in the 6GHz band, where legal regulations on transmit power density are strict.

[0009] Incidentally, the IEEE 802.11ax and IEEE 802.11be standards employ a technology called Dual Carrier Modulation (DCM). DCM is a technology that transmits the same data using two subcarriers. This makes it possible to reduce the data error rate through the diversity effect, where the data is combined and decoded at the receiving end.

[0010] Applying DCM to DRU makes it possible to further reduce the data error rate and extend the communication distance for communications using DRU. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2023-47755 [Patent Document 2] Special Publication No. 2024-516188 [Overview of the project] [Problems that the invention aims to solve]

[0012] Even if two communication devices support communication with DCM applied to the DRU, if both devices are unaware that DCM is being applied to the DRU during communication, a misunderstanding may occur, potentially preventing proper communication.

[0013] One aspect of this disclosure, in view of the above, aims to provide a technology for appropriately performing communication by applying DCM to a DRU. [Means for solving the problem]

[0014] A communication device according to one aspect of the present disclosure is a communication device compliant with the IEEE802.11 standard series, and includes information requesting to apply Dual Carrier Modulation (DCM) to a Distributed-tone Resource Unit (DRU), and has a transmission means for transmitting a frame requesting data transmission to another communication device.

Advantages of the Invention

[0015] According to one aspect of the present disclosure, communication applying DCM to DRU can be appropriately performed.

Brief Description of the Drawings

[0016] [Figure 1] A diagram showing a configuration example of a wireless communication system according to an embodiment. [Figure 2] A diagram showing a functional configuration example of a communication device according to an embodiment. [Figure 3] A diagram showing a hardware configuration example of a communication device according to an embodiment. [Figure 4] A diagram showing the concepts of DRU and distributed bands. [Figure 5] A diagram showing the concept of a PPDU with a bandwidth of 160 MHz. [Figure 6] A diagram showing an example of a set of subcarriers modulated based on the same data according to an embodiment. [Figure 7] A diagram showing an example of the configuration of the bandwidth and distributed bands of a PPDU according to an embodiment. [Figure 8] A diagram showing an example of DRUs constituting a 20 MHz distributed band and subcarriers constituting each DRU according to an embodiment. [Figure 9] A diagram showing an example of DRUs constituting a 40 MHz distributed band and subcarriers constituting each DRU according to an embodiment. [Figure 10] A diagram showing an example of DRUs constituting an 80 MHz distributed band and subcarriers constituting each DRU according to an embodiment. [Figure 11] A diagram showing an example of frame exchange between communication devices according to an embodiment. [Figure 12]A diagram showing an example of the operation of an AP in an association procedure according to an embodiment. [Figure 13] A diagram showing an example of the operation of a STA in an association procedure according to an embodiment. [Figure 14] A diagram showing an example of frame exchange in a data exchange procedure according to an embodiment. [Figure 15] A diagram showing an example of the operation of an AP in a data exchange procedure according to an embodiment. [Figure 16] A diagram showing an example of the operation of a STA in a data exchange procedure according to an embodiment. [Figure 17] A diagram showing a configuration example of a UHR Capabilities element according to an embodiment. [Figure 18] A diagram showing a configuration example of a Trigger frame according to an embodiment.

Mode for Carrying Out the Invention

[0017] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the content described in the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential to the present disclosure, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant descriptions are omitted.

[0018] <Embodiment> (Network Configuration) FIG. 1 is a diagram showing a configuration example of a wireless communication system according to the present embodiment. FIG. 1 shows a configuration example of a network according to the present embodiment. FIG. 1 shows a configuration including one AP (Access Point) 102 and three STAs (Station) 103, 104, and 105 as (wireless) communication devices that perform wireless LAN communication conforming to the IEEE802.11bn standard. The STA may also be called a non-AP STA.

[0019] As shown in Figure 1, the network formed by AP102 is indicated by circle 101. STA103-105 can transmit and receive signals transmitted and received by AP102. In this embodiment, AP102 and STA103-105 are sometimes collectively referred to as the communication device 100. Note that the configuration shown in Figure 1 is just one example, and other communication devices performing wireless LAN communication may exist in a wider area, for example.

[0020] The communication device 100 may be a communication device that performs wireless LAN communication compliant with the IEEE 802.11bn standard. Alternatively, the communication device 100 may be a so-called legacy device that does not comply with the IEEE 802.11bn standard but only with the IEEE 802.11a / b / g / n / ac / ax / be standards.

[0021] The communication device 100 can also be configured to support wireless communication based on other communication standards such as Bluetooth®, NFC, and Bluetooth LE (Low Energy). NFC is an abbreviation for Near Field Communication.

[0022] Furthermore, the communication device 100 can also be configured to support wired communication using Ethernet® cables or wired communication using optical fibers.

[0023] Furthermore, the communication device 100 can also be configured to support cellular wireless communication such as 5G (NR (New Radio)) and LTE (Long Term Evolution).

[0024] Specific examples of AP102 include, but are not limited to, wireless LAN routers and personal computers (PCs).

[0025] Specific examples of STA103-105 include, but are not limited to, cameras, tablets, smartphones, PCs, mobile phones, video cameras, smart glasses, and wearable devices such as HMDs (head-mounted displays). Furthermore, STA103-105 may also be IoT devices such as Internet of Things (IoT) sensors, smart locks, and smart sensors. IoT sensors may include accelerometers, light sensors, humidity sensors, etc.

[0026] Furthermore, the communication device 100 may be an information processing device such as a wireless chip capable of performing wireless communication compliant with IEEE 802.11 standards such as the IEEE 802.11bn standard. Alternatively, the communication device 100 may be an information processing device such as a wireless chip that supports the transmission and reception of Physical Layer Protocol Data Units (PPDUs). In this case, the wireless chip can be configured to perform various controls using hardware circuits within it. It is also possible to configure the wireless chip to perform various processes through the cooperation of a processor such as an ASIP, memory, and hardware circuits within it. ASIP is an abbreviation for Application-Specific Instruction Set Processor.

[0027] The following describes an example where AP102 is an AP compliant with the IEEE 802.11 standard, and each of STA103-105 is an STA compliant with the IEEE 802.11 standard.

[0028] (AP and STA configuration) Figure 2 is a block diagram showing examples of the functional configurations of AP102 and STA103-105. As an example of its functional configuration, AP102 has a capability information storage unit 200, an RU allocation unit 201, a frame generation and analysis unit 202, and a frame transmission and reception unit 203, as shown in Figure 2(a). On the other hand, as an example of its functional configuration, STA103-105 has a capability information storage unit 200, a frame generation and analysis unit 202, and a frame transmission and reception unit 203, as shown in Figure 2(b). In other words, the RU allocation unit 201 is present only in AP102 and not in STA103-105.

[0029] These functions can be realized, for example, by the memory unit 301 described later, or by the control unit 302 described later executing a program stored in the memory unit 301, or by the processing function unit in the communication unit 306 described later. Figure 2 is a diagram illustrating the main functions in this embodiment, and other functions are omitted. For this reason, for example, AP102 and STA103-105 may naturally have functions for establishing a connection between AP and STA and control for communication, as well as functions that communication devices generally have. In addition, the multiple function blocks shown in Figure 2 may be integrated into one function block, or one function block may be divided into multiple function blocks. Also, the names of the function blocks shown in Figure 2 are merely examples and may be changed.

[0030] The capability information storage unit 200 stores capability information indicating the capabilities of its device in relation to the IEEE 802.11 standard series. In this embodiment, the capabilities include whether or not it supports DRU, whether or not it supports DCM, etc. For example, the capabilities include supporting both DRU and DCM (in other words, being able to apply DCM to DRU). In this specification and drawings, the expressions "store capability information" and "store capabilities" are used interchangeably.

[0031] The RU allocation unit 201 determines the multiple access method to be used for communication with STA103-105. Multiple access methods include OFDMA. If the RU allocation unit 201 determines that OFDMA should be used, it determines whether to use RRU or DRU and allocates either RRU or DRU to STA103-105. The RU allocation unit 201 makes these decisions based on the number of STAs connected to AP102, the traffic between one or more connected STAs, the frequency band being used, the distance to the STAs, etc. For example, the RU allocation unit 201 determines that OFDMA should be used if the number of STAs is large (e.g., more than a predetermined number) and the traffic between each STA is small (e.g., less than a predetermined value). Furthermore, the RU allocation unit 201 determines that DRU should be used if the 6GHz band is being used or if the distance to the STAs is long (e.g., more than a predetermined value).

[0032] Furthermore, the RU allocation unit 201 may decide to apply DCM if the STA's communication environment is poor. A poor STA communication environment is, for example, when the STA's communication quality is below a threshold. The STA's communication quality may be represented by at least one of the following parameters: communication distance, interference amount, SNR (Signal-to-Noise Ratio), error rate, etc.

[0033] The frame generation and analysis unit 202 generates frames to be output to the frame transmission / reception unit 203 according to the multiple access scheme determined by the RU allocation unit 201, and analyzes the frames input from the frame transmission / reception unit 203.

[0034] Furthermore, the frame generation and analysis unit 202 performs adaptive rate control. Adaptive rate control is a process that appropriately changes the data rate or modulation and coding scheme (MCS: Modulation and Coding Scheme, hereinafter simply referred to as MCS) used based on the communication quality. In addition, the frame generation and analysis unit 202 also appropriately changes the use of DCM based on the communication quality. The frame generation and analysis unit 202 uses DCM when the communication quality is poor, etc., and does not use DCM when the communication quality is good, etc. For example, if the frame generation and analysis unit 202 does not receive a response to a frame transmitted by its own device, or if the frame received from the communication partner contains an error, it will change to a lower data rate MCS or start using DCM.

[0035] The frame generation and analysis unit 202 writes the information necessary for the communication partner to analyze or generate the frame into the frame's preamble or header.

[0036] The frame transmission / reception unit 203 encodes the frame input from the frame generation / analysis unit 202, modulates the encoded frame, and transmits the modulated frame as radio waves to the wireless medium. These encoding, modulation, and transmission processes are performed by the frame transmission / reception unit 203 according to the multiple access scheme determined by the RU allocation unit 201, and whether or not MCS and DCM are used determined by the frame generation / analysis unit 202. The frame transmission / reception unit 203 also demodulates the radio waves (including frame information) received from the wireless medium, decodes the received frame, and outputs the decoded frame to the frame generation / analysis unit 202. The frame transmission / reception unit 203 is an example of a transmission means, receiving means, transmission / reception means, or communication means.

[0037] Figure 3 shows an example of the hardware configuration of AP102 and STA103-105 (communication device 100).

[0038] AP102 and STA103-105, as an example of their hardware configuration, include a storage unit 301, a control unit 302, a function unit 303, an input unit 304, an output unit 305, a communication unit 306, and a wireless antenna 307.

[0039] The storage unit 301 is composed of one or more memories, such as both ROM and RAM, or either one of them, and stores various information such as programs for performing various operations described later, and communication parameters (setting information) for wireless communication. In addition to memories such as ROM and RAM, storage media such as flexible disks, hard disks, SSDs, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, and DVDs may be used as the storage unit 301. SSD is an abbreviation for Solid State Drive. CD-ROM is an abbreviation for Compact Disc Read Only Memory, CD-R is an abbreviation for Compact Disc Recordable, and DVD is an abbreviation for Digital Versatile Disc.

[0040] The control unit 302 is composed of, for example, one or more processors such as a CPU or MPU, an ASIC (Application-Specific Integrated Circuit), a DSP (Digital Signal Processor), or an FPGA (Field-Programmable Gate Array). CPU is an abbreviation for Central Processing Unit, and MPU is an abbreviation for Micro Processing Unit. The control unit 302 controls the entire device by executing a program stored in the memory unit 301. Alternatively, the control unit 302 may control the device in cooperation with the OS (Operating System) and the program stored in the memory unit 301.

[0041] Furthermore, the control unit 302 controls the functional unit 303 to perform predetermined processes such as imaging, printing, and projection. The functional unit 303 is hardware for the AP or STA to perform predetermined processes. For example, if the AP or STA is a camera, the functional unit 303 is the imaging unit and performs imaging processing. Also, for example, if the AP or STA is a printer, the functional unit 303 is the printing unit and performs printing processing. Also, for example, if the AP or STA is a projector, the functional unit 303 is the projection unit and performs projection processing. The data processed by the functional unit 303 may be data stored in the storage unit 301, or it may be data communicated with other communication devices via the communication unit 306, which will be described later.

[0042] The input unit 304 accepts various operations from the user. The output unit 305 provides various outputs to the user. Here, the output from the output unit 305 includes at least one of the following: display on the screen, audio output from a speaker, vibration output, etc. Note that both the input unit 304 and the output unit 305 may be implemented in a single module, such as a touch panel. Furthermore, the input unit 304 and the output unit 305 may be integrated with the AP or STA, respectively, or they may be separate components.

[0043] The communication unit 306 includes a so-called wireless LAN chip and controls wireless communication compliant with the IEEE 802.11 standard series, IP (Internet Protocol) communication, etc. In this embodiment, the communication unit 306 can perform processing compliant with at least the IEEE 802.11bn standard. The communication unit 306 is a processing device that generates UHR PPDU (Ultra High Reliability Physical layer Protocol Data Unit) as defined in the IEEE 802.11bn standard. The communication unit 306 may also have the function of generating types of PPDU defined in standards prior to the IEEE 802.11bn standard. Furthermore, the communication unit 306 controls the wireless antenna 307 to transmit and receive wireless signals for wireless communication. The communication device 100 communicates content such as image data, document data, and video data with other communication devices via the communication unit 306. The name UHR PPDU is a name provided for convenience to identify that it is a PPDU compliant with the IEEE 802.11bn standard. Therefore, it may have a different name. If a PPDU conforms to a specified standard other than UHR, the UHR PPDU may be replaced with a different name.

[0044] The wireless antenna 307 may be physically composed of two or more antennas in order to realize MIMO (Multi-Input and Multi-Output) transmission and reception. The wireless antenna 307 may be configured separately from the communication unit 306, or it may be configured as a single module together with the communication unit 306. The wireless antenna 307 is an antenna capable of communication in the 2.4GHz, 5GHz, 6GHz, 45GHz, and 60GHz bands. In Figure 3, the communication device 100 is shown to have one antenna, but it may have two or more antennas. Alternatively, the communication device 100 may have different antennas for each frequency band.

[0045] In the example shown in Figure 3, the communication device 100 is configured to have only one communication unit 306, but it is also possible to provide a separate communication unit for each of the multiple wireless antennas.

[0046] Furthermore, AP102 and STA103-105 can be any communication device having the configuration shown in Figures 2 and 3, and are not limited to the examples of equipment mentioned above.

[0047] (Concepts of DRU and Distributed Bandwidth) Next, the concepts of DRU and distributed bandwidth will be explained using Figure 4.

[0048] In Figure 4, the PPDU bandwidth 400 is shown. The bandwidth of the PPDU bandwidth 400 can be 20 MHz, 40 MHz, 80 MHz, 160 MHz, or 320 MHz.

[0049] In Figure 4, the distributed bands 401-403 are also shown. The bandwidths of each of the distributed bands 401-403 can be 20 MHz, 40 MHz, or 80 MHz. Alternatively, the bandwidths of the distributed bands 401-403 are not limited to the aforementioned values, but may be integer multiples or fractions of 20 MHz. The bandwidths of the distributed bands 401-403 may all be the same, some may be different, or all may be different.

[0050] A single PPDU bandwidth may contain one or more distributed bandwidths. Figure 4 shows an example where a single PPDU bandwidth 400 contains three distributed bandwidths 401-403. If a single PPDU bandwidth contains only one distributed bandwidth, the bandwidth of the PPDU and the bandwidth of the distributed bandwidth may coincide.

[0051] In Figure 4, for example, if the bandwidth of PPDU bandwidth 400 is 80 MHz, the bandwidths of dispersive bandwidth 401, dispersive bandwidth 402, and dispersive bandwidth 403 can be 20 MHz, 20 MHz, and 40 MHz, respectively.

[0052] A single dispersive bandwidth may contain one or more DRUs. In the case of dispersive bandwidth 401, dispersive bandwidth 401 contains four DRUs: DRU1-DRU4. The subcarriers constituting each DRU are discontinuously arranged throughout the entire dispersive bandwidth 401. That is, from lower frequencies to higher frequencies, the subcarriers of DRU1, DRU2, DRU3, and DRU4 are repeatedly arranged. The subcarriers constituting a DRU may include a data subcarrier and a pilot subcarrier.

[0053] Each dispersion band may include unused subcarriers that do not belong to any DRU. Unused subcarriers may include guard subcarriers, DC (Direct Current) subcarriers, etc. Unused subcarriers may exist between the subcarriers that constitute the DRU.

[0054] Similar to distributed bandwidth 401, distributed bandwidth 402 and distributed bandwidth 403 may also contain one or more DRUs.

[0055] Each dispersive band may contain one or more RRUs. An RRU is a RU first defined in IEEE 802.11ax. The subcarriers constituting an RRU are arranged consecutively on the frequency axis. The subcarriers constituting an RRU may include a data subcarrier and a pilot subcarrier. Even if a dispersive band contains an RRU, it may also contain unused subcarriers that do not belong to any RRU. Unused subcarriers may include guard subcarriers, DC subcarriers, etc. Unused subcarriers may be located between the subcarriers constituting an RRU.

[0056] Furthermore, DRUs and RRUs do not coexist in the same dispersed bandwidth. Also, the subcarriers constituting the RU are not dispersed within a dispersed bandwidth containing an RRU. Therefore, a dispersed bandwidth containing an RRU may be referred to by other names such as a subband or normal bandwidth.

[0057] (Concept of a PPDU with a bandwidth of 160MHz) If the bandwidth of the PPDU is 160 MHz or 320 MHz, the relationship between that bandwidth, the dispersion bandwidths that can be placed within that bandwidth, and the DRUs that can be placed within those dispersion bandwidths may be a repetition of the relationship for the 80 MHz bandwidth on the frequency axis.

[0058] Figure 5 shows a conceptual diagram of a PPDU with a bandwidth of 160 MHz. In Figure 5, the PPDU bandwidth 500 is shown. As shown in Figure 5, the bandwidth of the PPDU bandwidth 500 is 160 MHz. In Figure 5, bandwidths 501 and 502, which have a bandwidth of 80 MHz, are also shown. As shown in Figure 5, when the PPDU bandwidth is 160 MHz, the 80 MHz bandwidth is repeated twice on the frequency axis. Note that when the PPDU bandwidth is 320 MHz, the 80 MHz bandwidth is repeated four times on the frequency axis.

[0059] (Example of a set of subcarriers modulated based on the same data) Next, we will explain, using Figure 6, how to construct a set of subcarriers modulated based on the same data, that is, a set of subcarriers to which DCM is applied.

[0060] Figure 6 shows an example of a set of subcarriers modulated based on the same data. In Figure 6, an exemplary dispersed bandwidth 401 is shown.

[0061] A subcarrier pair is composed of two data subcarriers, obtained by dividing a single dispersed bandwidth data subcarrier into two groups: a high-frequency group and a low-frequency group, and selecting one data subcarrier from each group. For example, if one subcarrier is the i-th data subcarrier from the lower frequency group that constitutes the DRU, then the other subcarrier will be the i+(number of data subcarriers constituting the DRU / 2)-th data subcarrier from the lower frequency group. i is a natural number less than (number of data subcarriers / 2)+1. By composing a subcarrier pair with subcarriers that are far apart in frequency, resistance to frequency-selective fading can be strengthened.

[0062] Figure 7 shows an example of the bandwidth and distributed bandwidth configuration of a PPDU.

[0063] As shown in the leftmost column of Figure 7, the PPDU bandwidths include three types: 20 MHz, 40 MHz, and 80 MHz. Note that the configuration of the dispersed bandwidth when the PPDU bandwidth is 160 MHz and 320 MHz is, as explained using Figure 6, the same as the configuration when the PPDU bandwidth is 80 MHz, repeated two and four times on the frequency axis, respectively.

[0064] The modes shown in the second column from the left in Figure 7 are numbers used to identify the configuration of each distributed bandwidth within the bandwidth of each PPDU. This mode is also called DBW (Distributed Bandwidth) mode.

[0065] The bandwidths 1-4 shown in the 3rd to 6th columns from the left in Figure 7 are all 20 MHz bandwidths. They are named bandwidth 1, bandwidth 2, bandwidth 3, and bandwidth 4, from lowest to highest frequency.

[0066] For example, if the PPDU bandwidth is 80 MHz, there can be six modes, from 0 to 5. For example, in mode 2, the bandwidth of a PPDU with a bandwidth of 80 MHz consists of a 40 MHz distributed band placed in the combined band of bands 1 and 2, a 20 MHz distributed band placed in band 3, and a 20 MHz band placed in band 4.

[0067] Note that the distributed bandwidth configuration is not limited to the example shown in Figure 7. For example, if the PPDU bandwidth is 80 MHz, only modes 0, 1, 2, and 4 shown in Figure 7 may exist. In this case, there are four types of modes, and therefore the number of bits required to represent each mode is 2 bits, which is less than the 3 bits required for six types.

[0068] Figures 8, 9, and 10 show examples of DRUs that constitute the 20MHz, 40MHz, and 80MHz dispersion bands, respectively, and the subcarriers that make up each DRU.

[0069] The configuration of DRUs is defined for each distributed bandwidth. Each DRU is assigned an index (DRU index). Within each DRU, the arrangement of subcarriers is indicated using subcarrier indices. Subcarrier indices are integers assigned sequentially (ascending integers) to the subcarriers included in the distributed bandwidth, from lower frequency subcarriers to higher frequency subcarriers. For example, subcarrier indices are assigned as follows: For a 20MHz bandwidth, subcarrier indices of -121 to 121 are assigned. For a 40MHz bandwidth, subcarrier indices of -244 to 244 are assigned. For an 80MHz bandwidth, subcarrier indices of -500 to 500 are assigned. For a 160MHz bandwidth, subcarrier indices of -1012 to 1012 are assigned. Note that these subcarrier indices also include unused subcarriers.

[0070] Similar to RRUs, DRUs are classified by the number of data subcarriers and pilot subcarriers that make up the DRU. This classification is called the RU type. The RU types include 26-tone DRUs, 52-tone DRUs, 106-tone DRUs, 242-tone DRUs, and 484-tone DRUs. These RU types of DRUs consist of 26, 52, 106, 242, and 484 data subcarriers and pilot subcarriers, respectively. The number of data subcarriers and pilot subcarriers used in the classification, i.e., 26, 52, 106, 242, and 484, is the same as that for RUs, i.e., RRUs, as defined in the IEEE 802.11ax / be standard.

[0071] [S1, S2, ···] described in FIGS. 8 to 10 represents that the DRU is composed of subcarriers of a set of indexes corresponding to S1, S2, ···. Each of S1 and S2 represents an index of one subcarrier, a set of indexes of a plurality of subcarriers, or a set of indexes constituting the DRU. Also, [s1:d:s2] described in FIGS. 8 to 10 represents a set of indexes of index s1, all indexes satisfying index s1 + d (d is a natural number, s1 + d < s2), and index s2.

[0072] For example, the 26-tone DRU7[-120:9:-12,6:9:114] in the 20 MHz bandwidth shown in FIG. 8 is a DRU composed of 26 subcarriers. The 26 subcarriers are as follows when represented by subcarrier indexes. -120, -111, -102, -93, -84, -75, -66, -57, -48, -39, -30, -21, -12, 6, 15, 24, 33, 42, 51, 60, 69, 78, 87, 96, 105, 114. When applying DCM to this DRU and constructing a set of subcarriers as described using FIG. 6, the set of subcarriers is, for example, (-120 and 6), (-111 and 15), ···, (-12 and 114).

[0073] Furthermore, the 52-tone DRU and 106-tone DRU shown in Figure 8 are constructed based on combinations of 26-tone DRUs. For example, 52-tone DRU3 in a 20MHz bandwidth consists of 26-tone DRU7 and 26-tone DRU8. In this case, the DRU is composed of 52 subcarriers. The 52 subcarriers, when represented by subcarrier indices, include the following: -120, -116, -111, -107, -102, -98, -93, -89, -84, -80, -75, -71, -66, -62, -57, -53, -48, -44, -39, -35, -30, -26, -21, -17, -12, -8. The 52 subcarriers, when represented by subcarrier indices, further include the following: 6, 10, 15, 19, 24, 28, 33, 37, 42, 46, 51, 55, 60, 64, 69, 73, 78, 82, 87, 91, 96, 100, 105, 109, 114, 118. When DCM is applied to this DRU and a set of subcarriers is constructed as explained using Figure 6, the set of subcarriers will be, for example, (-120 and 6), (-116 and 10), ..., (-12 and 114), (-8 and 118).

[0074] In this embodiment, the number of subcarriers constituting the DRU is the same as in the RRU, and they are regularly arranged across the entire dispersion band. However, the number and arrangement of subcarriers constituting the DRU are not limited to this. For example, the number of subcarriers constituting the DRU may be less or more than the number of subcarriers constituting the RRU. Also, for example, the subcarriers constituting the DRU may be arranged irregularly. However, the subcarriers must be distributed across the dispersion band and have a lower power density than in the RRU case.

[0075] Furthermore, the distributed bandwidths are 20MHz, 40MHz, and 80MHz, and the supported RU types for each of these bandwidths are as follows: For a 20MHz distributed bandwidth, the supported RU types are 26-tone DRU, 52-tone DRU, and 106-tone DRU. For a 40MHz distributed bandwidth, the supported RU types are 26-tone DRU, 52-tone DRU, 106-tone DRU, and 242-tone DRU. For an 80MHz distributed bandwidth, the supported RU types are 52-tone DRU, 106-tone DRU, 242-tone DRU, and 484-tone DRU.

[0076] However, this disclosure is not limited to the foregoing. In the case of an 80 MHz distributed bandwidth, a 26-tone DRU may be used, and in the case of a 160 MHz distributed bandwidth, communication using DRUs may be implemented. When using a 26-tone DRU in an 80 MHz distributed bandwidth, the 26-tone DRU can be newly allocated to 37 STAs, so DRU1 to DRU70 will be used as DRU indices.

[0077] Furthermore, the subcarrier to which DCM is applied is modulated with BPSK and coded with BCC or LDPC at a coding rate of 1 / 2. BPSK is an abbreviation for Binary Phase Shift Keying, BCC is an abbreviation for Binary Convolutional Code, and LDPC is an abbreviation for Low Density Parity Check. This makes it possible to provide a combination of modulation and coding schemes that is more noise-resistant than any data rate or MCS without DCM in the IEEE 802.11 standard series.

[0078] However, other primary modulation schemes and encoding schemes may be applied in DCM. For example, any of MCS0 to 4 may be applied. Alternatively, any of MCS0, 1, 3, and 4 may be applied. Furthermore, for example, a modulation scheme with a modulation level below a predetermined value and an encoding scheme with a coding rate below a predetermined value may be applied. Specifically, modulation schemes and encoding schemes such as QPSK with a coding rate of 1 / 2, 16QAM with a coding rate of 1 / 2, and 16QAM with a coding rate of 3 / 4 may be applied. QPSK is an abbreviation for Quadrature Phase Shift Keying, and QAM is an abbreviation for Quadrature Amplitude Modulation. This allows for a more flexible selection of modulation scheme and encoding scheme combinations depending on the required data rate, the noise environment of the transmission line, etc.

[0079] Furthermore, the number of spatial streams may be limited in DCM. For example, the number of spatial streams may be set to 1 or 2. Also, DCM and STBC (Space-Time Block Coding) do not necessarily have to be applied in combination.

[0080] (Operation of the wireless communication system) Next, we will explain how the wireless communication system works.

[0081] Figure 11 shows an example of frame exchange between communication devices.

[0082] AP102 transmits Beacon frames at predetermined (time) intervals called Beacon Intervals. In the example shown in Figure 11, each of Beacon frames 1101-1103 is transmitted by AP102 at predetermined intervals.

[0083] The Beacon frame includes an Information Element (IE) containing information indicating the capabilities regarding the application of DCM to a DRU, such as whether the device is capable of applying DCM to the DRU (whether DCM can be applied to the DRU). This IE is an IE added in the IEEE 802.11bn standard or a standard issued after that standard. This IE may also be called a UHR Capabilities element. Details of this IE will be described later using Figure 17. Note that the name UHR Capabilities element is a name provided for convenience to identify it as a UHR Capabilities element compliant with the IEEE 802.11bn standard. Therefore, it may have a different name.

[0084] By receiving the Beacon frame, STA103-105 can recognize the capabilities of AP102, such as its ability to apply DCM to AP102's DRU (for example, the capabilities indicated by the information stored in fields 1720-1724, described later).

[0085] STA103-105 may also send a Probe Request frame to AP102. Then, STA103-105 may receive a Probe Response frame from AP102, which includes the above-mentioned IE, as a response to the Probe Request frame. By receiving the Probe Response frame, STA103-105 can recognize the capabilities of AP102.

[0086] Furthermore, each of the STA103-105 units may include the above-mentioned IE in the Probe Request frame it sends to AP102. Upon receiving a Probe Request frame containing the above-mentioned IE, AP102 can recognize the capabilities of each of the STA103-105 units, such as their ability to apply DCM to each of their DRUs.

[0087] Furthermore, as will be described later using Figure 12, STA103-105 may send an Association Request frame containing the above IE to AP102. Then, as will be described later using Figure 13, AP102 may send an Association Response frame containing the above IE to STA103-105 in response.

[0088] Additionally or alternatively, a FILS frame (which may also be called a FILS Discovery frame or FILS Discovery Announcement frame) containing the above IE may be transmitted. FILS stands for Fast Initial Link Setup. Furthermore, an Unsolicited Probe Response frame (which may also be called a Broadcast Probe Response frame) containing the above IE may be transmitted. FILS frames and Unsolicited Probe Response frames may be transmitted by the AP in the same way as Beacon frames. These also allow STA103-105 to recognize the capabilities of AP102.

[0089] Figure 11 also shows period 1111, during which STA103-105 performs the procedure (referred to as the association procedure) for associating with the BSS (Basic Service Set) managed by AP102. The operation of AP102 and STA103-105 during this period 1111 will be described later using Figures 12 and 13.

[0090] Figure 11 also shows period 1121 during which AP102 and STA103-105 perform a data exchange procedure (referred to as the data exchange procedure). The operation of AP102 and STA103-105 during this period 1121 will be described later using Figures 15 and 16.

[0091] Figure 12 is a diagram illustrating an example of AP operation in an association procedure, showing an example of AP102's operation flow during period 1111, when STA103-105 performs the procedure to associate with the BSS managed by AP102.

[0092] This operation flow starts when the AP102 is powered on and the wireless LAN is enabled.

[0093] In step S1200, AP102 determines whether it has received an Association Request frame from STA103-105 (this can be replaced by a determination (the same applies below)). If AP102 determines that it has received an Association Request frame (Yes in step S1200), it proceeds to step S1201; otherwise (No in step S1200), it proceeds to step S1202.

[0094] In step S1201, AP102 stores the capabilities of STA103-105 regarding the IEEE 802.11 standard series, as contained in the received Association Request frame, in the capability information storage unit 200. Also in step S1201, AP102 sends an Association Response frame to STA103-105, which sent the received Association Request frame. Then AP102 proceeds to step S1202.

[0095] In step S1202, AP102 determines whether the wireless LAN has been disabled by a user or other party. If AP102 determines that the wireless LAN has been disabled (Yes in step S1202), it terminates this operation flow; otherwise (No in step S1202), it returns to step S1200.

[0096] Figure 13 is a diagram illustrating an example of STA operation in an association procedure, showing an example of the operation flow of STA103-105 during period 1111, when STA103-105 performs the procedure to associate with the BSS managed by AP102.

[0097] This operation flow begins when power is turned on to the STA103-105 and the wireless LAN is enabled.

[0098] In step S1300, STA103-105 sends an Association Request frame to AP102. Then, STA103-105 proceeds to step S1301.

[0099] In step S1301, STA103-105 determines whether it has received an Association Response frame from AP102. If STA103-105 determines that it has received an Association Response frame (Yes in step S1301), it proceeds to step S1302; otherwise (No in step S1301), it terminates this operation flow.

[0100] In step S1302, STA103-105 stores the capabilities of AP102 regarding the IEEE 802.11 standard series, as contained in the Association Response frame, in the capability information storage unit 200. Then, STA103-105 terminates this operation flow.

[0101] AP102 may include an IE in the Association Response frame it transmits that indicates its ability to apply DCM to its DRU. Similarly, STA103-105 may include an IE in the Association Request frame it transmits that indicates its ability to apply DCM to its DRU. This IE is an IE added in the IEEE 802.11bn standard or a standard issued after that standard. This IE may also be called the UHR Capabilities element. Details of this IE will be described later with reference to Figure 17.

[0102] AP102 can recognize the capabilities of STA103-105 by receiving an Association Request frame in step S1200. STA103-105 can recognize the capabilities of AP102 by receiving an Association Response frame in steps S1301-S1302.

[0103] Figure 14 shows an example of frame exchange in a data exchange procedure, illustrating an example of frame exchange during period 1121 when AP102 and STA103-105 perform a data exchange procedure.

[0104] AP102 sends Trigger frame 1400 to STA103-105, which it wants to transmit PPDUs (TB (Trigger Based) PPDUs) containing uplink data (uplink data). Trigger frame 1400 contains requests for TB PPDUs 1401-1403, which STA103-105 will subsequently transmit. These requests include the bandwidth of the TB PPDU, the DBW mode, the distributed bandwidth and RU used by each STA, and whether DCM is applied to each RU. Note that RU can be RRU or DRU. Furthermore, if the TB PPDU bandwidth is 160MHz or 320MHz, information indicating the DBW mode is included for every 80MHz bandwidth. Therefore, if the TB PPDU bandwidth is 160MHz or 320MHz, Trigger frame 1400 contains information indicating two or four DBW modes, respectively. Details of Trigger frame 1400 will be described later using Figure 18.

[0105] Upon receiving Trigger frame 1400, STA103-105 each transmit TB PPDU1401-1403 to AP102. STA103-105 each transmit TB PPDU1401-1403 in accordance with the above request contained in Trigger frame 1400.

[0106] Upon receiving TB PPDU1401-1403, AP102 sends Block ACK frame 1404 to STA103-105.

[0107] Figure 15 is a diagram illustrating an example of AP operation in a data exchange procedure, showing an example of AP102's operation flow during period 1121 in which AP102 and STA103-105 perform a data exchange procedure.

[0108] This operation flow is initiated when AP102 determines that it should have STA103-105 send a TB PPDU. For example, this initiation timing occurs when AP102 recognizes, via Buffer Status Report Operation, that data that STA103-105 should send is queued in STA103-105.

[0109] In step S1500, AP102 sends a Trigger frame to STA103-105. Then AP102 proceeds to step S1501.

[0110] In step S1501, AP102 determines whether it has successfully received the TB PPDU from STA103-105. If AP102 determines that it has successfully received the TB PPDU (Yes in step S1501), it proceeds to step S1502; otherwise (No in step S1501), it terminates this operation flow.

[0111] In step S1502, AP102 sends a Block ACK frame to STA103-105. Then, AP102 terminates this operation flow.

[0112] In step S1501, AP102 may determine whether each of STA103-105 has successfully received the TB PPDU from STA103-105. Then, in step S1502, AP102 may send a Block ACK frame containing the result of the determination in step S1501 to STA103-105. In this case, the process that branches to No in step S1501 is not executed.

[0113] Figure 16 is a diagram illustrating an example of STA operation in a data exchange procedure, showing an example of the operation flow of STA103-105 during period 1121 in which AP102 and STA103-105 perform a data exchange procedure.

[0114] In step S1600, STA103-105 determines whether it has received a Trigger frame from AP102. If STA103-105 determines that it has received a Trigger frame (Yes in step S1600), it proceeds to step S1601; otherwise (No in step S1600), it terminates this operation flow.

[0115] In step S1601, STA103-105 sends a TB PPDU to AP102. Then, STA103-105 terminates this operation flow.

[0116] (IE and frame configuration) Next, the configuration of the IE and frame related to this embodiment will be described.

[0117] Figure 17 shows an example configuration of the UHR Capabilities element.

[0118] A UHR Capabilities element may include an Element ID field 1701, a Length field 1702, and an Element ID Extension field 1703. The combination of Element ID field 1701 and Element ID Extension field 1703 indicates the type of element. For example, an element with Element ID field 1701 set to 255 and Element ID Extension field 1703 set to 138 is a UHR Capabilities element. The Length field 1702 indicates the length of this element.

[0119] The UHR Capabilities element may also include a UHR MAC Capabilities Information field 1704 that indicates capabilities related to MAC (Medium Access Control).

[0120] The UHR Capabilities element may also include a UHR PHY Capabilities Information field 1705 that indicates capabilities related to the PHY (Physical layer).

[0121] The UHR PHY Capabilities Information field 1705 may include the DRU Support subfield 1711 and the Supported DRU Type subfield 1712. The UHR PHY Capabilities Information field 1705 may also include the Supported DRU Distributed Band Width subfield 1713. The UHR PHY Capabilities Information field 1705 may also include the Supported Distributed Band Width Mode subfield 1714.

[0122] The DRU Support subfield 1711 indicates whether or not the device supports DRU. This field is a 1-bit field. A value of 1 indicates that the device supports DRU, while a value of 0 indicates that the device does not support DRU.

[0123] The Supported DRU Type subfield 1712 indicates the RU type of the DRU that is supported. This field is a 3-bit field. A value of 0 ("000") in decimal indicates that only 26-tone RUs are supported. A value of 1 ("001") in decimal indicates that RUs with 52-tone and fewer than 52 subcarriers are supported. A value of 2 ("010") in decimal indicates that RUs with 106-tone and fewer than 106 subcarriers are supported. A value of 3 ("011") in decimal indicates that RUs with 242-tone and fewer than 242 subcarriers are supported. A value of 4 ("100") in decimal indicates that RUs with 484-tone and fewer than 484 subcarriers are supported. Other values ​​may indicate that they correspond to RUs with a higher number of subcarriers and RUs with a lower number of subcarriers, or they may be marked as Reserved.

[0124] Furthermore, the Supported DRU Type subfield 1712 may be a 5-bit field, a bitmap-style field where each bit indicates whether or not it corresponds to one RU type. In this case, bits 0, 1, 2, 3, and 4 may indicate whether or not it corresponds to a 26-tone RU, 52-tone RU, 106-tone RU, 242-tone RU, and 484-tone RU, respectively. The Supported DRU Type subfield 1712 may have even more bits to indicate whether or not it supports more RU types. If this field indicates whether or not it supports an RU type in bitmap format, the values ​​of the bits may indicate the following: For example, a bit value of 1 may indicate that it corresponds to the associated RU type, and a bit value of 0 may indicate that it does not support the associated RU type.

[0125] The Supported DRU Distributed Bandwidth subfield 1713 indicates the supported DRU distribution bandwidth. This field is a 2-bit field. A decimal value of 0 indicates support for a 20MHz distribution bandwidth. A decimal value of 1 indicates support for 40MHz and narrower distribution bandwidths. A decimal value of 2 indicates support for 80MHz and narrower distribution bandwidths.

[0126] Furthermore, the Supported DRU Distributed Band Width subfield 1713 may be a 3-bit field. A decimal value of 0 in this field may indicate a 20 MHz distribution bandwidth. A decimal value of 1 in this field may indicate a 40 MHz and narrower distribution bandwidth. A decimal value of 2 in this field may indicate a 80 MHz and narrower distribution bandwidth. A decimal value of 3 in this field may indicate a 160 MHz and narrower distribution bandwidth. A decimal value of 4 in this field may indicate a 320 MHz and narrower distribution bandwidth.

[0127] Whether this field is a 2-bit or 3-bit field, other values ​​may indicate that they correspond to RUs of wider and narrower distribution bandwidths, or they may be marked as Reserved.

[0128] Furthermore, the Supported DRU Distributed Bandwidth subfield 1713 may be a 3-bit field, a bitmap-style field where each bit indicates whether or not it corresponds to one distributed bandwidth. In this case, bits 0, 1, and 2 may indicate whether or not it corresponds to 20MHz, 40MHz, and 80MHz, respectively.

[0129] Furthermore, the Supported DRU Distributed Bandwidth subfield 1713 may be a 5-bit field in the form of a bitmap, where each bit indicates whether or not it corresponds to one distributed bandwidth. In this case, bits 0, 1, 2, 3, and 4 may indicate whether or not they correspond to 20MHz, 40MHz, 80MHz, 160MHz, and 320MHz, respectively.

[0130] Additionally, the Supported DRU Distributed Bandwidth subfield 1713 may indicate whether it has more bits and supports a greater distributed bandwidth.

[0131] If the Supported DRU Distributed Band Width subfield 1713 indicates whether or not it corresponds to a distributed bandwidth in bitmap format, the bit values ​​may indicate the following: For example, a bit value of 1 may indicate that it corresponds to the associated distributed bandwidth, and a bit value of 0 may indicate that it does not correspond to the associated distributed bandwidth.

[0132] Furthermore, subfields 1711, 1712, and 1713 may be combined into a single field, either partially or entirely. In this case, the encoding of the information in the combined field may differ from that described above. For example, if all three fields are combined into a single field, the value of this field may indicate, for example, the following: A decimal value of 0 in this field may indicate that it does not correspond to a DRU. A decimal value of 1 in this field may indicate that it corresponds to a 26-tone RU and a 20MHz dispersion bandwidth. A decimal value of 2 in this field may indicate that it corresponds to a 26-tone RU and a 40MHz dispersion bandwidth. Similarly, a decimal value of 3 or greater in this field may indicate the corresponding RU type and dispersion bandwidth combination.

[0133] The Supported Distributed Bandwidth Mode subfield 1714 indicates the supported DBW modes. This field is a 3-bit field. Values ​​of 0, 1, and 2 may indicate that the corresponding DBW modes have maximum distributed bandwidths of 20 MHz, 40 MHz, and 80 MHz, respectively. For example, using the DBW modes shown in Figure 7, if the PPDU bandwidth is 80 MHz, a value of 1 in this field indicates that it corresponds to modes 1-5 (mode 0 does not correspond because its distributed bandwidth is 80 MHz).

[0134] The UHR PHY Capabilities Information field 1705 may include the DCM DRU Support subfield 1720 and the DCM Max DRU Type subfield 1721. The UHR PHY Capabilities Information field 1705 may also include the DCM Max DRU Distributed Band Width subfield 1722. The UHR PHY Capabilities Information field 1705 may also include the DCM Max DRU Constellation subfield 1723 and the DCM Max DRU NSS subfield 1724.

[0135] The DCM DRU Support subfield 1720 indicates whether or not DCM can be applied to a DRU (DCM application is supported). This field is a 1-bit field. A value of 1 in this field indicates that DCM can be applied to a DRU, and a value of 0 indicates that DCM cannot be applied to a DRU.

[0136] The DCM Max DRU Type subfield 1721 indicates the RU types to which DCM can be applied for a DRU. The value of this field indicates that DCM can be applied to RU types and RU types with fewer subcarriers than the given RU type. This field is a 3-bit field. The decimal values ​​of this field are 0, 1, 2, 3, and 4, which indicate 26-tone RU, 52-tone RU, 106-tone RU, 242-tone RU, and 484-tone RU, respectively.

[0137] The DCM Max DRU Distributed Bandwidth subfield 1722 indicates the maximum distributed bandwidth to which DCM can be applied for a DRU. This field is a 2-bit field. A value of 0, 1, and 2 in decimal indicates that DCM can be applied to a maximum distributed bandwidth of 20 MHz, 40 MHz, and 80 MHz, respectively. This field may be a 3-bit (or more than 4-bit) field. In this case, a value of 0, 1, 2, 3, and 4 in decimal may indicate that DCM can be applied to a maximum distributed bandwidth of 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz, respectively. Other values ​​may indicate an even wider maximum distributed bandwidth to which DCM can be applied, or may be marked as Reserved.

[0138] The DCM Max DRU Constellation subfield 1723 indicates the maximum number of primary modulation levels to which DCM can be applied for the DRU. This field is a 2-bit field. A value of 0, 1, and 2 in decimal indicates that DCM can be applied up to BPSK, QPSK, and 16QAM, respectively.

[0139] The DCM Max DRU NSS subfield 1724 indicates the maximum number of spatial streams to which DCM can be applied for a DRU. This field is a 1-bit field. A value of 0 or 1 indicates that DCM can be applied to 1 spatial stream and a maximum of 2 spatial streams, respectively.

[0140] The DCM DRU Support subfield 1720 does not exist, and any of the subfields 1721-1724 may indicate whether or not DCM is applicable to the DRU. For example, a value of 0 in the DCM Max DRU Type subfield 1721 may indicate that DCM is not applicable to the DRU. In this case, a non-zero value in this field may indicate that DCM is applicable to the DRU. In this case, a decimal value of 1, 2, and 3 in this field may indicate that DCM is applicable up to 26-tone RU, 52-tone RU, and 106-tone RU, respectively. Similarly, in this case, a decimal value of 4 and 5 in this field may indicate that DCM is applicable up to 242-tone RU and 484-tone RU, respectively. Also, for example, a value of 0 in the DCM Max DRU Constellation subfield 1723 may indicate that DCM is not applicable to the DRU. In this case, a non-zero value in this field may indicate that DCM is applicable to the DRU. In this case, a decimal value of 1, 2, and 3 in this field may indicate that DCM is applicable up to BPSK, QPSK, and 16QAM, respectively. Similarly, the DCM Max DRU Distributed Band Width subfield 1722 and the DCM Max DRU NSS subfield 1724 may also indicate that DCM is applicable to the DRU. If the value of any of these subfields indicates whether or not DCM is applicable to the DRU, the number of bits in that field may be increased from the number of bits described above, as necessary.

[0141] In addition, subfields 1720-1724 may indicate only the receiving capability in the case of AP102, and only the transmitting capability in the case of STA103-105.

[0142] Alternatively, subfields 1720-1724 may be made common to both DRU and RRU, indicating the ability to apply DCM to both. In this case, it becomes unnecessary to provide similar fields for each of the DRU and RRU, thus reducing the amount of data stored in the frame.

[0143] Figure 18 shows an example of the configuration of a Trigger frame.

[0144] The Trigger frame 1400 shown in Figure 14 may include a Frame Control field 1801, a Common Info field 1802, and a User Info List field 1803.

[0145] The Frame Control field 1801 may include the Type subfield 1811 and the Subtype subfield 1812. The Type subfield 1811 and the Subtype subfield 1812 indicate the function of the frame.

[0146] The Type subfield 1811 indicates whether the frame is Management, Control, or Data. For Trigger frame 1400, the Type subfield 1811 takes a value indicating that it is Control.

[0147] The Subtype subfield 1812 indicates the subtype of the frame. Subtypes include Probe Request, Probe Response, and Beacon. Further subtypes include RTS (Request To Send), CTS (Clear To Send), Block Ack (Acknowledgement), Ack, Data, and Trigger. In the case of Trigger frame 1400, the Subtype subfield 1812 takes a value indicating that it is a Trigger.

[0148] The Common Info field 1802 contains information common to the communication device targeted by the Trigger frame. The Common Info field 1802 may include the Trigger Type subfield 1821, the UL BW subfield 1822, the DBW Mode subfield 1823, and the DRU / RRU Indication subfield 1824.

[0149] The Trigger Type subfield 1821 indicates the variant of the Trigger frame. Variants include Basic, MU-RTS (Multi User Request To Send), etc. In the case of Trigger frame 1400, the Trigger Type subfield 1821 takes a value indicating that it is Basic. However, it is not limited to this value; any value that allows STA103-105 to be requested to send data using RU is acceptable. Trigger frame 1400 is an example of a frame that requests STA103-105 to send data using RU (RRU or DRU). Furthermore, Trigger frame 1400 in cases where the DRU / RRU Indication subfield 1824, described later, takes the value "1", is an example of a frame that requests STA103-105 to send data using DRU.

[0150] The UL BW subfield 1822, along with the UL Bandwidth Extension subfield 1841 (described later), indicates the frequency bandwidth of the TB PPDU that is triggered by the Trigger frame.

[0151] The DBW Mode subfield 1823 indicates the DBW mode used by the TB PPDU whose transmission is triggered by the Trigger frame. This field is the (minimum) number of bits that can indicate the number of modes that exist in the IEEE 802.11 standard series when the TB PPDU bandwidth is 80 MHz. That is, the number of bits in this field is an integer obtained by rounding up the decimal part of log2(number of modes). For example, in the mode configuration shown in Figure 7, there are 6 modes, so the number of bits in this field is 3 bits. However, for example, if only modes 0, 1, 2, and 4 exist as shown in Figure 7, there are 4 modes, so the number of bits in this field is 2 bits. Also, if the PPDU bandwidth is 20 MHz, there is only 1 mode, so this field does not need to exist. Also, if the PPDU bandwidth is 40 MHz, there are only 2 modes, so the number of bits in this field may be 1 bit. In this way, the number of bits may change depending on the PPDU bandwidth.

[0152] Furthermore, the DBW Mode subfield 1823 may indicate the bandwidth and mode combination of the PPDU. In this case, the number of bits in this field is an integer obtained by rounding up the decimal part of log2 (the number of bandwidth and mode combinations of the PPDU). For example, in the case of the PPDU bandwidth and mode configuration shown in Figure 7, there are 9 modes (combinations), so the number of bits in this field is 4 bits.

[0153] Furthermore, if the PPDU bandwidth is 160 MHz or 320 MHz, the DBW Mode subfield 1823 may exist every 80 MHz, indicating the corresponding 80 MHz DBW mode. In this case, if the PPDU bandwidth is 160 MHz, there will be two DBW Mode subfields 1823 within the PPDU, and if the PPDU bandwidth is 320 MHz, there will be four DBW Mode subfields 1823 within the PPDU.

[0154] Furthermore, the DBW Mode subfield 1823 may reside in the Special User Info field 1831, which will be described later, instead of the Common Info field 1802.

[0155] The DRU / RRU Indication subfield 1824 indicates whether the distributed bandwidth constituting the DBW mode, as indicated by the DBW Mode subfield 1823, is composed of RRUs or DRUs. This field has a number of bits equal to the maximum number of distributed bandwidths constituting the DBW mode that exist in the IEEE 802.11 standard series. For example, in the distributed bandwidth configuration shown in Figure 7, there are a maximum of four distributed bandwidths, so this field has 4 bits. Each bit corresponds to one distributed bandwidth; a bit value of 1 indicates that the distributed bandwidth is composed of RRUs, and a bit value of 0 indicates that the distributed bandwidth is composed of DRUs. Also, if the PPDU bandwidth is 20 MHz, there is only one distributed bandwidth, so this field may have 1 bit. Also, if the PPDU bandwidth is 40 MHz, there are a maximum of two distributed bandwidths, so this field may have 2 bits. Thus, the number of bits may change depending on the PPDU bandwidth.

[0156] Furthermore, if the PPDU bandwidth is 160 MHz or 320 MHz, the DRU / RRU Indication subfield 1824 may exist every 80 MHz, indicating information about the corresponding 80 MHz bandwidth. In this case, if the PPDU bandwidth is 160 MHz, there will be two DRU / RRU Indication subfields 1824 within the PPDU. Similarly, if the PPDU bandwidth is 320 MHz, there will be four DRU / RRU Indication subfields 1824 within the PPDU.

[0157] Furthermore, the DRU / RRU Indication subfield 1824 may reside in the Special User Info field 1831, which will be described later, instead of the Common Info field 1802.

[0158] Furthermore, the DRU / RRU Indication subfield 1824 described above may indicate whether each distributed band, which may have a bandwidth of 80 MHz or less, is composed of RRUs or DRUs. However, if the RUs constituting the entire 80 MHz bandwidth are unified to either RRUs or DRUs, this field may be simplified. In this case, for example, this field indicates whether each band of the 80 MHz bandwidth is composed of DRUs or RRUs. This field consists of four bits: B0, B1, B2, and B3. B0 indicates whether the band of the lowest frequency 80 MHz bandwidth is composed of DRUs or RRUs. B1 indicates whether the band of the second lowest frequency 80 MHz bandwidth is composed of DRUs or RRUs. B3 indicates whether the band of the second highest frequency 80 MHz bandwidth is composed of DRUs or RRUs. B4 indicates whether the highest frequency 80MHz bandwidth is composed of a DRU or RRU. If the PPDU bandwidth is 20MHz, 40MHz, or 80MHz, B1-B3 are treated as Reserved. If the PPDU bandwidth is 160MHz, B2-B3 are treated as Reserved. A bit value of 0 indicates that the corresponding 80MHz bandwidth is composed of a DRU, and a bit value of 1 indicates that the corresponding 80MHz bandwidth is composed of an RRU.

[0159] Note that the DBW Mode subfield 1823 and the DRU / RRU Indication subfield 1824 may exist as a single field. In this case, the information from the two fields may be encoded and represented.

[0160] The User Info List field 1803 may contain the Special User Info field 1831 and the User Info field 1832. The User Info List field 1803 typically contains multiple User Info fields, corresponding to the number of TB PPDU sources whose transmission is triggered by the Trigger frame.

[0161] The Special User Info field 1831 is a field that extends the Common Info field 1802. Like the Common Info field 1802, the Special User Info field 1831 contains information common to the communication device targeted by the Trigger frame. The Special User Info field 1831 may include the UL Bandwidth Extension subfield 1841.

[0162] The UL Bandwidth Extension subfield 1841, together with the UL BW subfield 1822, indicates the frequency bandwidth of the TB PPDU that is triggered by the Trigger frame. Here, the UL BW subfield 1822 can take values ​​indicating a frequency bandwidth of 20 MHz, 40 MHz, 80 MHz, 160 MHz, or wider than 160 MHz. The UL Bandwidth Extension subfield 1841 can take values ​​indicating 20 MHz, 40 MHz, 80 MHz, 160 MHz, or 320 MHz. The UL Bandwidth Extension subfield 1841 may also take values ​​indicating a frequency bandwidth other than those listed above, such as 640 MHz.

[0163] The User Info field 1832 contains information (user information) about one of the source communications devices (STAs (which may be interpreted by the user)) of the TB PPDU whose transmission is triggered by the Trigger frame. The User Info field 1832 may include the AID12 subfield 1851 and the RU Allocation subfield 1852. The User Info field 1832 may also include the UL UHR-MCS subfield 1853, the UL DCM subfield 1854, and the PS 160 subfield 1855.

[0164] The AID12 subfield 1851 contains an identifier for identifying the communication device targeted by the User Info field 1832.

[0165] The RU Allocation subfield 1852 is a field that indicates resource allocation. The RU Allocation subfield 1852 includes information indicating whether the RU assigned to the communication device targeted by the User Info field 1832 is an RRU or a DRU, and information indicating the RU index. The information indicating whether the RU is an RRU or a DRU is included in the information indicating the RU index, and whether the RU is an RRU or a DRU may be distinguished by the value of the RU index. Also, the bits containing the information indicating whether the RU is an RRU or a DRU may be different from the bits containing the information indicating the RU index. If the bandwidth of the PPDU is wider than 80 MHz, the RU Allocation subfield 1852 may, together with the PS 160 subfield 1855, include information indicating which 80 MHz band the RU is located in.

[0166] The UL UHR-MCS subfield 1853 indicates the MCS applicable to the RU assigned to the communication device covered by the User Info field 1832. The number of bits in this field is an integer rounded up from the decimal part of either (A) or (B) below: (A) log2 (the maximum index value of the MCS applicable to the RU of a TB PPDU in the IEEE 802.11 standard series + 1). (B) log2 (the maximum number of MCS types applicable to the RU of a TB PPDU in the IEEE 802.11 standard series). In case (A), the value of this field matches the value of the MCS index. For example, in (A), if the maximum index value of the above MCS is 15, the number of bits in this field is 4. Also, for example, in (B), if the maximum number of MCS types is 15, the number of bits in this field is 4.

[0167] The UL DCM subfield 1854 indicates whether DCM should be applied to the RU assigned to the communication device targeted by the User Info field 1832. This field is a 1-bit field. A value of 1 in this field indicates that DCM should be applied to the RU, and a value of 0 indicates that DCM should not be applied to the RU. The "information indicating that the RU assigned to the communication device is a DRU" in the RU Allocation subfield 1852 and the value "1" in the UL DCM subfield 1854 are examples of information that requests the application of DCM to the DRU.

[0168] Furthermore, if an MCS index is assigned to a primary modulation scheme and DCM combination (for example, a combination of BPSK and DCM), the UL DCM subfield 1854 does not need to exist. In this case, information indicating whether or not to apply DCM to the RU is included in the UL UHR-MCS subfield (for example, the MCS index indicating the primary modulation scheme and DCM combination). The following information is an example of information requesting the application of DCM to a DRU: "Information indicating that the RU assigned to the communication device is a DRU" in the RU Allocation subfield 1852 and the value of the UL UHR-MCS subfield "MCS index indicating the primary modulation scheme and DCM combination". Furthermore, the primary modulation scheme and DCM combination to which an MCS index is assigned is not limited to the BPSK and DCM combination, but may also be a combination of QPSK and DCM, a combination of 16QAM and DCM, etc.

[0169] The PS 160 subfield 1855 may, together with the RU Allocation subfield 1852, include the following information when the PPDU bandwidth is wider than 80 MHz: that is, the PS 160 subfield 1855, together with subfield 1852, may include information indicating which 80 MHz bandwidth the RU assigned to the communication device targeted by User Info field 1832 is located in.

[0170] The positions of the RRU and DRU on the frequency axis are determined by at least the values ​​of the UL BW subfield 1822 and the RU Allocation subfield 1852. The positions of the RRU and DRU on the frequency axis may also be determined by considering one or both of the values ​​of the UL Bandwidth Extension subfield 1841 and the PS 160 subfield 1855.

[0171] <Other Embodiments> The above describes subfields 1721-1724, which indicate whether DCM can be applied to a DRU. However, whether DCM can be applied to a DRU can also be indicated by extending the (sub)fields specified in conventional standards. For example, the following subfields in IEEE 802.11ax / be, etc., may be used in an extended form: DCM Max Constellation TX subfield, DCM Max Constellation RX subfield, DCM Max NSS TX subfield, and / or DCM Max NSS RX subfield. For example, some or all of these subfields may be extended, such as by increasing the number of bits, to accommodate cases where DCM can be applied to a DRU. Alternatively, these existing subfields may be used in conjunction with fields indicating whether a DRU or RRU is used (e.g., DRU / RRU Indication subfield 1824, RU Allocation subfield 1852, etc.). In this case, subfields 1723 and 1724 do not need to exist.

[0172] Furthermore, combinations of values ​​for some or all of the subfields 1720-1724 and their corresponding indices or IDs may be predetermined. That is, two or more of the following information (a) to (e) may be included in one field of the UHR Capabilities element: (a) Information indicating whether DCM is applicable to the DRU; (b) Information indicating the RU types to which DCM is applicable for the DRU; (c) Information indicating the DBW to which DCM is applicable for the DRU; (d) Information indicating the maximum number of primary modulation levels to which DCM is applicable for the DRU; (e) Information indicating the maximum number of spatial streams to which DCM is applicable for the DRU. For example, the values ​​of subfields 1720-1724 and their indices may be associated as shown in Table 1 below.

[0173] [Table 1] Furthermore, instead of storing its own capabilities in subfields 1720-1724, the communication device 100 may notify the other device of its capabilities by storing an index or ID in a separate subfield provided for storing an index or ID. In this case, subfields 1720-1724 do not need to exist.

[0174] The same applies to subfields 1711-1713. That is, combinations of values ​​for some or all of subfields 1711-1713 and their corresponding indices or IDs may be predetermined. The communication device 100 may notify the device's capabilities by storing the index or ID in a separate subfield provided for storing the index or ID, instead of storing it in subfields 1711-1713. In this case, subfields 1711-1713 do not need to exist.

[0175] In the above explanation, the RU Allocation subfield 1852 and the UL DCM subfield 1854 (or UL UHR-MCS subfield 1853) were described as indicating whether or not DCM should be applied to a DRU allocated to a communication device. However, whether or not DCM should be applied to a DRU allocated to a communication device may be indicated in other ways. For example, the RU Allocation subfield 1852 may indicate that DCM should be applied to a DRU allocated to a communication device if it includes information indicating a predetermined RU index along with information indicating that the allocated RU is a DRU. The "information indicating that the allocated RU is a DRU" and the "information indicating a predetermined RU index" in the RU Allocation subfield 1852 are examples of information that requests the application of DCM to a DRU. Alternatively, if the distinction between an RRU and a DRU is made by the value of the RU index, the information indicating a predetermined RU index may indicate that DCM should be applied to a DRU allocated to a communication device. In this case, the "information indicating a predetermined RU index" in the RU Allocation subfield 1852 is an example of information that requests the application of DCM to a DRU.

[0176] The arrangement of fields constituting IEs and frames is not limited to the examples shown in the diagrams and tables of this application, and they may be arranged in a different order. Furthermore, IEs and frames do not have to include all the fields shown in the diagrams and tables of this application, and may include only some of the fields. IEs and frames may also include additional fields different from those shown in the diagrams and tables of this application.

[0177] The combination of a field (including subfields) value and its corresponding meaning (what the value represents) is not limited to the examples described above. For example, for a 1-bit field, the values ​​"1" and "0" may have opposite meanings. Also, for a 2-bit field, the following may apply: the meaning described above as representing "0 in decimal" may be represented by "1 in decimal" (or "2 in decimal" or "3 in decimal"), and "1 in decimal" may represent the meaning described above as representing other values. The same applies to fields with 3 or more bits, bitmap fields, etc.

[0178] A storage medium containing program code for software that implements the above-described functions may be supplied to a system or device, and the computer (CPU, MPU) of the system or device may read and execute the program code stored in the storage medium. In this case, the program code read from the storage medium itself implements the functions of the above-described embodiment, and the storage medium containing that program code constitutes the above-described device.

[0179] For supplying program code, storage media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, ROMs, DVDs, etc., can be used.

[0180] Furthermore, the above-mentioned functions may be realized not only by the computer executing the program code it reads, but also by the operating system running on the computer performing some or all of the actual processing based on the instructions of that program code.

[0181] Furthermore, the program code read from the storage medium is written to the memory of a function expansion board inserted into the computer or a function expansion unit connected to the computer. Then, based on the instructions of that program code, the CPU of the function expansion board or function expansion unit may perform some or all of the actual processing to realize the above-mentioned functions.

[0182] This disclosure can also be implemented by supplying a program that implements one or more of the functions of the embodiments described above to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. Furthermore, this disclosure can also be implemented by a circuit (e.g., an ASIC) that implements one or more functions.

[0183] Furthermore, some of the processes described in this disclosure with reference to the flowchart may be implemented in hardware. For example, a dedicated circuit can be automatically generated on the FPGA from a program to implement each step by using a predetermined compiler. Alternatively, a Gate Array circuit may be formed in the same way as the FPGA and implemented in hardware.

[0184] The names of the functional units, messages, parameters, fields, etc., described in the embodiments described above may be changed to other names.

[0185] The order of the processing procedures, sequences, flowcharts, etc., in the embodiments described above is not limited to the specific order presented, and may be rearranged or additional steps may be added, as long as they do not contradict each other.

[0186] As described above, the communication device (AP or STA) according to this embodiment transmits an IE containing information indicating whether or not DCM can be applied to the DRU. The information indicating whether or not DCM can be applied to the DRU is, for example, the value of the DCM DRU Support subfield 1720. The IE containing the above information is, for example, a UHR Capabilities element. This allows the communication device to notify the communication partner (STA or AP) whether or not it supports communication with DCM applied to the DRU, thereby enabling proper communication with DCM applied to the DRU.

[0187] Furthermore, the communication device (AP or STA) according to this embodiment includes information requesting the application of DCM to the DRU and transmits a frame requesting data transmission to other communication devices. The information requesting the application of DCM to the DRU is, for example, the values ​​of the RU Allocation subfield 1852 and the UL DCM subfield 1854. The frame requesting data transmission is, for example, a Trigger frame. This allows the communication device to request (or notify) the application of DCM to the DRU during data transmission, thereby enabling proper communication with DCM applied to the DRU.

[0188] Furthermore, the following additional information is disclosed regarding the above embodiments.

[0189] [Note 1] A communication device compliant with the IEEE 802.11 standard series, A communication device having a transmission means for transmitting a frame that includes information requesting the application of Dual Carrier Modulation (DCM) to a Distributed-tone Resource Unit (DRU) and requests data transmission to another communication device.

[0190] [Note 2] A communication device compliant with the IEEE 802.11 standard series, A communication device having receiving means for receiving a frame that requests the communication device to transmit data, which includes information requesting the application of Dual Carrier Modulation (DCM) to a Distributed-tone Resource Unit (DRU).

[0191] [Note 3] The frame is a communication device as described in Appendix 1 or 2, which requests the transmission of data using the DRU.

[0192] [Note 4] The aforementioned frame is a trigger frame, as described in any of the appendices 1 to 3 of the communication device.

[0193] [Note 5] The aforementioned information is included in a field indicating user information, and is a communication device as described in any of the appendices 1 to 4.

[0194] [Note 6] The aforementioned information is included in the field indicating the modulation coding scheme, and is a communication device as described in any of the appendices 1 to 5.

[0195] [Note 7] The field indicating the modulation coding scheme is a communication device as described in Appendix 6, which indicates a predetermined modulation scheme.

[0196] [Note 8] The aforementioned predetermined modulation scheme includes the BPSK (Binary Phase Shift Keying) modulation scheme, as described in Appendix 7 of the communication device.

[0197] [Note 9] The aforementioned information is included in the field indicating resource allocation, and is a communication device as described in Appendix 1 or 2.

[0198] [Note 10] The aforementioned information is distributed across a field containing information common to multiple users and a field indicating user information, as described in any of the appendices 1 to 4 of the communication device.

[0199] [Note 11] The communication device as described in Appendix 10, wherein the field containing information common to the multiple users indicates whether or not DRU is applied for each bandwidth of the 80 MHz bandwidth, and the field indicating user information indicates the modulation coding scheme.

[0200] [Note 12] A communication method for communication devices compliant with the IEEE 802.11 standard series, A communication method comprising the step of sending a frame that requests the application of Dual Carrier Modulation (DCM) to a Distributed-tone Resource Unit (DRU) and requests data transmission to another communication device.

[0201] [Note 13] A communication method for communication devices compliant with the IEEE 802.11 standard series, A communication method comprising the step of receiving a frame that requests the communication device to transmit data, which includes information requesting the application of Dual Carrier Modulation (DCM) to a Distributed-tone Resource Unit (DRU).

[0202] [Note 14] A program that causes a computer to execute the communication method described in Appendix 12 or 13. [Explanation of Symbols]

[0203] 102 Communication equipment (AP) 103, 104, 105 Communication equipment (STA)

Claims

1. A communication device compliant with the IEEE 802.11 standard series, A communication device having transmitting means for transmitting a frame that requests other communication devices to transmit data, which includes information requesting the application of Dual Carrier Modulation (DCM) to a Distributed-tone Resource Unit (DRU).

2. A communication device compliant with the IEEE 802.11 standard series, A communication device having receiving means for receiving a frame that requests the communication device to transmit data, which includes information requesting the application of Dual Carrier Modulation (DCM) to a Distributed-tone Resource Unit (DRU).

3. The communication device according to claim 1 or 2, wherein the frame requests the data transmission using the DRU.

4. The communication device according to claim 1 or 2, wherein the frame is a Trigger frame.

5. The communication device according to claim 1 or 2, wherein the aforementioned information is included in a field indicating user information.

6. The communication device according to claim 1 or 2, wherein the aforementioned information is included in a field indicating a modulation coding scheme.

7. The communication device according to claim 6, wherein the field indicates a predetermined modulation scheme.

8. The communication device according to claim 7, wherein the predetermined modulation scheme includes a BPSK (Binary Phase Shift Keying) modulation scheme.

9. The communication device according to claim 1 or 2, wherein the aforementioned information is included in a field indicating resource allocation.

10. The communication device according to claim 1 or 2, wherein the aforementioned information is distributed among a field containing information common to multiple users and a field indicating user information.

11. The communication device according to claim 10, wherein a field containing information common to the multiple users indicates whether or not DRU is applied to each bandwidth of the 80 MHz bandwidth, and a field indicating user information indicates a modulation coding scheme.

12. A communication method for communication equipment compliant with the IEEE 802.11 standard series, A communication method comprising the step of transmitting a frame that requests another communication device to transmit data, which includes information requesting that Dual Carrier Modulation (DCM) be applied to a Distributed-tone Resource Unit (DRU).

13. A communication method for communication equipment compliant with the IEEE 802.11 standard series, A communication method comprising the step of receiving a frame requesting data transmission from a communication device, which includes information requesting the application of Dual Carrier Modulation (DCM) to a Distributed-tone Resource Unit (DRU).

14. A program for causing a computer to execute the communication method described in claim 12 or 13.

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