Communication device, communication method, and program

Abstract

This invention provides a communication device and program that enable efficient operation of a communication device in a communication system that uses a communication link composed of multiple channels. [Solution] A communication device capable of transmitting a wireless frame conforming to one or more IEEE 802.11 standards to another communication device has a generation means for generating a wireless frame, which includes a preamble signal and a data signal, and a preamble signal including first information that allows the other communication device to identify which of a first or second mapping should be used to identify an MCS from an MCS index, and second information indicating an MCS index corresponding to an MCS used to generate the data signal; a data signal generated using an MCS indicated by the first information and the second information; and a transmission means for transmitting the generated wireless frame to another communication device, wherein the generated wireless frame includes the second information in the U-SIG field of the preamble signal.

Description

Technical Field

[0001] The present invention relates to data communication technology in a communication device that communicates using one Modulation and Coding Scheme (MCS) included in a plurality of MCSs.

Background Art

[0002] In recent years, with the increase in the amount of data to be communicated, 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 Electronic Engineers) 802.11 standard series is known. The IEEE 802.11 standard series includes IEEE 802.11a / b / g / n / ac / ax / be standards and the like. For further improvement of communication reliability, the development of the IEEE 802.11bn standard is underway as a successor standard to the IEEE 802.11be standard. In the IEEE 802.11WG (Working Group) that formulates the IEEE 802.11bn standard, in the UHR SG, the goals and scope of study of this standard are determined, and in TGbn, the detailed technical content to be included in this standard is planned to be defined. Note that UHR SG is an abbreviation for Ultra High Reliability Study Group. Also, TGbn is an abbreviation for Task Group bn.

[0003] In the current latest standard, the IEEE 802.11ax standard (Non-Patent Document 1), as the MCS with the maximum data rate, a combination of a modulation method of 1024-QAM and a coding rate of 5 / 6 is defined. On the other hand, in the formulation of the IEEE 802.11bn standard, studies are being conducted to diversify the combinations of Modulation and Coding Scheme (MCS) that can be used by communication devices.

Prior Art Documents

Non-Patent Documents

[0004] [Non-Patent Document 1] IEEE, “Wireless LAN MAC and PHY Specifications Amendment 1: Enhancements for High-Efficiency WLAN” [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The present invention provides a technology for appropriately notifying the other party's communication device of the MCS that a communication device will use for transmission in a communication system that can use multiple types of MCS. [Means for solving the problem]

[0006] A communication device according to one aspect of the present invention is a communication device capable of transmitting wireless frames conforming to one or more standards included in the IEEE 802.11 standard series to another communication device, wherein the device conforms to a plurality of Modulation and Coding standards defined in the first standard included in the standard series. At least a portion of the first correspondence between each Scheme (MCS) and an MCS index that uniquely identifies the MCS differs from the second correspondence specified in a second standard that was standardized prior to the first standard. The communication device has a generating means for generating a wireless frame which includes a preamble signal and a data signal, the preamble signal including first information that allows the other communication device to determine whether to use the first correspondence or the second correspondence to identify the MCS from the MCS index, and second information indicating the MCS index corresponding to the MCS used to generate the data signal, and a data signal generated using the MCS indicated by the first information and the second information, and a transmitting means for transmitting the wireless frame generated by the generating means to the other communication device, wherein the generating means generates the wireless frame which includes the first information in the Universal Signal (U-SIG) field of the preamble signal. [Effects of the Invention]

[0007] According to the present invention, in a communication system that can use multiple types of MCS, the communication device can appropriately notify the other party's communication device of the MCS that it will use for transmission. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram showing an example configuration of a wireless communication system. [Figure 2] This figure shows an example of the hardware configuration of a communication device. [Figure 3] This figure shows an example of the functional configuration of the transmitting communication device. [Figure 4] This figure shows an example of the functional configuration of the receiving communication device. [Figure 5] This figure shows an example of the processing flow that a communication device performs when transmitting a PPDU. [Figure 6] This figure shows an example of the processing flow that a communication device performs when receiving a PPDU. [Figure 7] This figure shows an example of a frame format that conforms to the second standard. [Figure 8] This diagram shows an example configuration of EHT-SIG. [Figure 9] This diagram shows an example configuration of EHT-SIG. [Figure 10] This figure shows an example of the configuration of a trigger frame. [Figure 11] This figure shows an example of the configuration of the User Info field. [Figure 12] This figure shows an example of a frame format conforming to the first standard. [Figure 13] This figure shows an example sequence of events performed between AP and STA. [Figure 14] This figure shows an example sequence of events performed between AP and STA. [Figure 15] This figure shows an example of the configuration of an MCS table. [Figure 16]This is a diagram showing a configuration example of U-SIG. [Figure 17] This is a diagram showing a configuration example of the Common field. [Figure 18] This is a diagram showing a configuration example of the User encoding block. [Figure 19] This is a diagram showing a configuration example of the User field. [Figure 20] This is a diagram showing a configuration example of the User field. [Figure 21] This is a diagram showing a configuration example of the Common field. [Figure 22] This is a diagram showing a configuration example of the User field. [Figure 23] This is a diagram showing a configuration example of the Common field. [Figure 24] This is a diagram showing a configuration example of U-SIG. [Figure 25] This is a diagram showing a configuration example of the User field. [Figure 26] This is a diagram showing a configuration example of the User field. [Figure 27] This is a diagram showing a configuration example of the MCS table. [Figure 28] This is a diagram showing a configuration example of the MCS table. [Figure 29] This is a diagram showing a configuration example of the MCS table. [Figure 30] This is a diagram showing a configuration example of the MCS table.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential for the invention, and the plurality of features may be arbitrarily combined. Furthermore, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant descriptions are omitted.

[0010] (System Configuration) Figure 1 shows an example configuration of a wireless communication system according to this embodiment. The wireless communication system includes, for example, an access point (AP) 101 and stations (STA) 111 and STA112. STA111 and STA112 are sometimes referred to as STA110 without distinction. Similarly, AP101 and STA110 are sometimes referred to as communication device 100 without distinction. Each of AP101 and STA110 is a communication device capable of performing wireless communication compliant with the IEEE 802.11 standard series. For example, each of AP101 and STA110 is configured to transmit and receive wireless frames compliant with the IEEE 802.11 standard series. IEEE is an abbreviation for Institute of Electrical and Electronics Engineers. Figure 1 shows a configuration in which STA111 and STA112 participate in a network 121 constructed by AP101. Network 121 may also be called a Basic Service Set (BSS). In network 121 in Figure 1, a configuration with one AP101 and two STAs is shown. However, there may be multiple APs, and there may be one or more STAs. In that case, each STA may be connected to one AP, or one STA may be connected to multiple APs.

[0011] In this embodiment, the communication device 100 is configured to execute a communication method compliant with the IEEE 802.11bn standard. The IEEE 802.11bn standard is the successor to the IEEE 802.11be standard, which aims for a maximum transmission speed of 46.08 Gbps (Gigabit per second). The main features of the IEEE 802.11bn standard are that it has functions that realize highly reliable communication, low latency communication, and improved throughput when communication traffic is congested. The wireless frame used in the communication method compliant with this standard may be called UHR (Ultra High Reliability) PPDU. PPDU is an abbreviation for PLCP Protocol Data Unit, and PLCP is an abbreviation for Physical Layer Convergence Protocol. Note that the names UHR and IEEE 802.11bn may be changed to other names when the standard is finalized. Furthermore, it should be noted that this specification and the claims attached herein are applicable to communication devices using all successor standards to IEEE 802.11be. Also, communication device 100 may support at least one of the legacy standards standardized prior to the IEEE 802.11bn standard. Legacy standards include, for example, the IEEE 802.11a / b / g / n / ac / ax / be standards. For example, a wireless frame used in a communication method compliant with the IEEE 802.11be standard may be called an EHT (Extremely High Throughput) PPDU. If communication device 100 supports both the IEEE 802.11be and IEEE 802.11bn standards, communication device 100 can support both communication using UHR PPDU and communication using EHT PPDU. Furthermore, communication device 100 may support other communication standards such as Bluetooth®, NFC, UWB, ZigBee, and MBOA. UWB is an abbreviation for Ultra Wide Band, MBOA is an abbreviation for Multi Band OFDM Alliance, and NFC is an abbreviation for Near Field Communication.UWB includes wireless USB, wireless 1394, WiNET, etc. The communication device 100 may also support communication standards such as wired LAN. AP101 is, for example, a wireless LAN router or a personal computer (PC), but is not limited to these. AP101 may be an information processing device such as a wireless chip capable of performing wireless communication compliant with legacy standards, IEEE 802.11bn standards, and their successor standards. STA110 is, for example, a camera, tablet, smartphone, PC, mobile phone, video camera, headset, smart glasses, HMD (head-mounted display), and other wearable devices, but is not limited to these. STA110 may be an information processing device such as a wireless chip capable of performing wireless communication supporting PPDU transmission and reception compliant with legacy standards, IEEE 802.11bn standards, and their successor standards. In this case, the wireless chip can be configured to perform various controls using internal hardware circuits. Furthermore, the wireless chip can be configured to perform various processes through the cooperation of a processor such as ASIP, memory, and hardware circuits. ASIP is an abbreviation for Application-specific instruction set processor.

[0012] The communication device 100 can communicate using radio signals in frequency bands such as the 2.4GHz, 3.6GHz, 5GHz, 6GHz bands, and millimeter wave bands such as the 45GHz and 60GHz bands. The frequency bands used by the communication device 100 are not limited to these, and may include, for example, the Sub1GHz band. Furthermore, the communication device 100 can communicate using bandwidths of 20MHz, 40MHz, 80MHz, 160MHz, 320MHz, 540MHz, 640MHz, 1080MHz, and 2160MHz. The bandwidths used by the communication device 100 are not limited to these, and may include, for example, 240MHz or 4MHz. Note that the IEEE 802.11 standard series specifies frequency channels using a 20MHz bandwidth as basic channels in frequency bands such as the 2.4GHz, 5GHz, and 6GHz bands. In addition, this standard defines multiple usable channels in each of the 2.4GHz, 5GHz, and 6GHz frequency bands.

[0013] Some standards included in the IEEE 802.11 standard series define combinations of modulation schemes and coding rates that can be used between communication devices. These combinations of modulation schemes and coding rates can be called Modulation and Coding Schemes (MCS). For example, the IEEE 802.11be standard considers the use of 15 MCS combinations, as shown in Figure 15. Each MCS, composed of a single modulation scheme and a single coding rate, is associated with an index called the MCS index, which uniquely identifies that MCS. For example, an MCS with the 4096-QAM modulation scheme and a coding rate of 5 / 6 would be associated with an MCS index value of 13. QAM is an abbreviation for Quadrature amplitude modulation. In this embodiment, the correspondence between MCSs and MCS indices as shown in Figure 15 will be referred to as the MCS table.

[0014] When the communication device 100 transmits data to the other party's communication device, it selects one MCS from among several MCSs specified in the standard to which it belongs. The communication device 100 generates a data signal to be transmitted to the other party's communication device using the selected MCS and transmits a PPDU containing this data signal. The communication device 100 uses a predetermined area included in the PPDU's preamble signal (preamble) to notify the other party's communication device of the MCS used by the communication device to generate the data signal. For example, in the IEEE 802.11be standard, a 4-bit EHT SIG field is planned to be provided in the preamble as a predetermined area for notifying the receiving communication device of the MCS used by the transmitting communication device. When the communication device 100 notifies the other party's communication device of the MCS used for transmission, it uses the MCS index associated with that MCS. For example, in the case of an EHT PPDU compliant with the IEEE 802.11be standard, the MCS index associated with the MCS used for transmission is set in the EHT SIG field. The receiving communication device can identify the MCS used by the transmitting side based on the MCS index set in the EHT SIG field of the preamble of the received EHT PPDU. The receiving communication device obtains the data contained in the PPDU by demodulating it based on the identified MCS.

[0015] On the other hand, the IEEE 802.11bn standard is considering diversifying the MCSs that communication devices can use. For example, MCSs using combinations of modulation schemes and coding rates of 2 / 3 for QPSK, 16QAM, and 256QAM may be added. Additionally, an MCS using a combination of the 16QAM modulation scheme and coding rates of 5 / 6 may be added. These MCSs are not used in legacy standards. The addition of these MCSs will increase the types of MCSs that can be used by STAs located in the intermediate region between AP101 and the end of the BSS, such as STA112 in Figure 1. This may improve the overall throughput of the BSS. If these four MCSs are added, it will be necessary to assign a new MCS index to each MCS. However, as mentioned above, in the IEEE 802.11be standard, the EHT SIG field for notifying the other communication device of the MCS is 4 bits, so it is not possible to assign a new MCS index to these added MCSs. For example, the decimal numbers that can be represented with 4 bits are in the range of 0 to 15, but as shown in Figure 15, there is only one index in this range that is not used: 14. Therefore, there are not enough indices to assign new indices to the four additional MCSs. Furthermore, the mapping between MCSs and MCS indices in the IEEE 802.11be standard is such that the value of the MCS index increases as the modulation level and coding rate increase. Therefore, if the four MCSs mentioned above are added, there is a possibility that the data may not be processed correctly due to differences in the interpretation of the MCS index values ​​defined in the respective standards between the transmitting and receiving communication devices. For example, suppose that different MCSs are mapped to the same MCS index in the IEEE 802.11bn standard and the IEEE 802.11be standard. In this case, if the transmitting communication device uses the first MCS table of the IEEE 802.11bn standard for transmission processing, and the receiving communication device uses the second MCS table of the IEEE 802.11be standard for reception processing, reception processing may not be performed correctly.

[0016] In light of these circumstances, the transmitting communication device 100 in this embodiment includes predetermined information for identifying the MCS from the MCS index included in the wireless frame in the preamble signal of the wireless frame. The predetermined information for identifying the MCS from the MCS index includes first information and second information. The first information is information that can identify whether to use a first MCS table or a second MCS table to identify the MCS from the MCS index. The second information is information that indicates the MCS index corresponding to the MCS used to generate the data signal included in the wireless frame. The first information may be included in the Universal Signal (U-SIG) field in the preamble. On the other hand, the receiving communication device 100 in this embodiment uses the first information and the second information included in the preamble signal of the received wireless frame to identify the MCS from the MCS index. For example, the receiving communication device 100 identifies whether to use a first MCS table or a second MCS table to identify the MCS from the MCS index based on the first information. Furthermore, the receiving communication device 100 uses the identified MCS table to identify the MCS from the MCS index indicated by the second information. The receiving communication device 100 then demodulates the data signal based on the identified MCS. This configuration makes it possible to match the MCS tables used to identify the MCS from the MCS index between the transmitting communication device 100 and the receiving communication device 100. As a result, even if the standards used by the transmitting communication device 100 and the receiving communication device 100 each include multiple standards in which at least part of the MCS table specified in the standards differs, the demodulation process of the wireless frame will be performed appropriately.

[0017] The first piece of information may be information indicating the standard to which the transmitted wireless frame conforms. If the MCS tables defined for each standard are different, the receiving communication device 100 can identify the MCS table it should use by knowing the standard to which the wireless frame conforms. The standard to which the wireless frame conforms may be indicated by the value of the PHY Version Identifier field in the U-SIG field. For example, if the wireless frame conforms to the first standard (IEEE 802.11bn standard), the PHY Version Identifier field may be set to a value greater than 0. Also, if the wireless frame conforms to the second standard (IEEE 802.11be standard), the PHY Version Identifier field may be set to a value of 0.

[0018] The first MCS table may include MCS not included in the second MCS table. For example, the first MCS table may include a first MCS using QPSK and a coding rate of 2 / 3, a second MCS using 16QAM and a coding rate of 2 / 3, a third MCS using 16QAM and a coding rate of 5 / 6, a fourth MCS using 64QAM and a coding rate of 2 / 3, and so on. For this reason, the MCS index used in the first MCS table may be represented by 5 bits. Furthermore, the first MCS table may be configured to include the first to fourth MCS, etc., and to assign smaller MCS index values ​​to MCS with lower data rates. In addition, the first MCS table may be configured to assign MCS indexes not used in the second MCS table to the first to fourth MCS, etc. An example configuration and processing example of a communication device 100 operating in this manner will be described below.

[0019] (Device configuration) Figure 2 shows an example of the hardware configuration of the communication device 100 in this embodiment. As an example of its hardware configuration, the communication device 100 includes, for example, a storage unit 201, a control unit 202, a function unit 203, an input unit 204, an output unit 205, a communication unit 206, and an antenna 207. The communication device 100 may have multiple antennas.

[0020] The storage unit 201 is composed of one or more memories, including ROM and RAM, and may store control programs for various operations of each functional unit constituting the communication device 100, as well as various information such as parameters for communication. ROM and RAM are abbreviations for Read Only Memory and Random Access Memory, respectively. In addition to memories such as ROM and RAM, the storage unit 201 may also be composed of storage media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, and DVDs.

[0021] The control unit 202 is composed of one or more processors, such as a CPU and an MPU, and controls the entire communication device 100 by executing a control program stored in the memory unit 201. Alternatively, the control unit 202 may control the entire communication device 100 through cooperation between the control program stored in the memory unit 201 and the OS (Operating System). CPU and MPU are abbreviations for Central Processing Unit and Micro Processing Unit, respectively. If the control unit 202 has multiple processors, such as a multi-core processor, it may be configured so that the entire communication device 100 is controlled by multiple processors.

[0022] Furthermore, the control unit 202 controls the functional unit 203 to perform predetermined processes such as communication, imaging, printing, and projection. The functional unit 203 is hardware that enables the communication device 100 to perform the predetermined processes described above. For example, if the device is a camera, the functional unit 203 is the imaging unit and performs imaging processing. Also, for example, if the device is a printer, the functional unit 203 is the printing unit and performs printing processing. Also, for example, if the device is a projector, the functional unit 203 is the projection unit and performs projection processing.

[0023] The input unit 204 receives various operations from the user. The output unit 205 outputs various information to the user via a monitor screen or speaker. The output from the output unit 205 may be a display on the monitor screen, audio output via a speaker, vibration output, etc. The input unit 204 and the output unit 205 may both be implemented in a single module, such as a touch panel. The input unit 204 and the output unit 205 may be integrated with the communication device 100, or they may be separate devices.

[0024] The communication unit 206 controls wireless communication compliant with the IEEE 802.11bn standard. In addition to the IEEE 802.11bn standard, the communication unit 206 may also control wireless communication compliant with other IEEE 802.11 standard series, such as legacy standards. For example, the communication unit 206 may support both wireless communication compliant with the IEEE 802.11be standard and wireless communication compliant with the IEEE 802.11bn standard. The communication unit 206 controls the antenna 207 to transmit and receive signals for wireless communication generated by the control unit 202. The communication unit 206 is a so-called wireless chip and may itself include one or more processors and memory. Furthermore, if the communication device 100 supports other wireless communication standards such as NFC and Bluetooth, or wired communication such as wired LAN, in addition to the IEEE 802.11bn standard, the communication unit 206 may control communication compliant with these communication standards. Furthermore, if the communication device 100 can perform wireless communication compliant with multiple communication standards, the communication device 100 may be configured to have separate communication units and antennas corresponding to each communication standard. The communication device 100 communicates data with the other party's communication device via the communication unit 206. The antenna 207 may be configured separately from the communication unit 206, or it may be configured as a single module together with the communication unit 206.

[0025] Antenna 207 is an antenna capable of communication in the 2.4GHz band, 5GHz band, 6GHz band, and millimeter wave bands such as 45GHz and 60GHz. Figure 2 shows a configuration in which the communication device 100 has two antennas 207, but the communication device 100 may have one or more antennas, and may have one or more antennas for each frequency band that the device can use. Also, if the communication device 100 has multiple antennas, the communication device 100 may have a communication unit 206 for each antenna. Antenna 207 may be physically composed of two or more antennas in order to realize (Multi-Input and Multi-Output) transmission and reception.

[0026] (Functional Configuration) Figure 3 shows an example of the functional configuration of the transmitting communication device 100. The functional configuration in this embodiment is an example of a functional configuration realized by, for example, one or more processors executing programs stored in one or more memories. The communication device 100 may include an MCS management unit 301, a communication control unit 302, a frame generation unit 303, a frame transmission unit 304, and a frame reception unit 305.

[0027] The MCS management unit 301 manages the MCS tables. For example, the MCS management unit 301 maintains MCS tables that correspond to the MCS and MCS index mappings specified in each standard to which the communication device 100 is compatible. When an MCS table is associated with a standard, the MCS management unit 301 can manage multiple MCS tables based on the standard to which the communication device 100 is compatible. For example, the MCS management unit 301 can maintain and manage a first MCS table specified in the IEEE 802.11bn standard and a second MCS table specified in the IEEE 802.11be standard. Furthermore, if multiple mappings between MCS and MCS indexes are specified in a single standard, the MCS management unit 301 can maintain multiple MCS tables corresponding to each mapping.

[0028] The communication control unit 302 performs control for communicating with the other party's communication device. For example, the communication control unit 302 may determine the type of PPDU to be used for communication and the MCS for generating data signals. The communication control unit 302 may identify the standards supported by the other party's communication device and select the PPDU to be used for communication according to the identified standards. For example, the communication control unit 302 in AP101 may identify the standards supported by STA111 and STA112 and select the PPDU to be used according to the data destination. As an example, if STA111 supports the first and second standards, and STA112 supports the second standard, AP101 may select the second standard in order to transmit data to STA111 and STA112 in parallel. The communication control unit 302 may also identify the MCS available to the other party's communication device and select the MCS to be used for communication according to the identified MCS. For example, the communication control unit 302 in AP101 can identify multiple MCSs that can be used by STA110 based on the standards that STA110 supports, and select an appropriate MCS from among them according to the channel conditions.

[0029] The frame generation unit 303 generates a PPDU. For example, the frame generation unit 303 generates a PPDU using the type of PPDU and MCS selected by the communication control unit 302. If the communication control unit 302 selects a type of PPDU that the other party's communication device should transmit based on the corresponding standard, the frame generation unit 303 can configure a PPDU corresponding to that type. For example, if the communication control unit 302 selects to transmit using a UHR MU PPDU, the frame generation unit 303 generates a preamble signal and data signals according to the configuration of a UHR MU PPDU to configure the PPDU. The frame generation unit 303 can generate data signals using the MCS selected by the communication control unit 302. The frame generation unit 303 also sets the MCS index corresponding to the MCS used to generate the data signals in the PPDU preamble. When generating a UHR MU PPDU, the frame generation unit 303 can use the first MCS table to identify the MCS index corresponding to the MCS used to generate the data signals and set it in the preamble. Furthermore, when generating an EHT MU PPDU, the frame generation unit 303 may use a second MCS table to identify the MCS index corresponding to the MCS used to generate the data signal and set it in the preamble. The frame generation unit 303 also sets information in the preamble that can identify the MCS table that the other party's communication device should use. For example, if the frame generation unit 303 has identification information that uniquely identifies the MCS table, it may set that identification information in the preamble. In addition, if a standard and an MCS table are associated, the frame generation unit 303 may notify the other party's communication device of information that identifies the MCS table that the generated PPDU conforms to.

[0030] Furthermore, the frame generation unit 303 of STA110 can generate a PPDU based on the information contained in the Trigger frame received from AP101. In this case, the frame generation unit 303 can generate a PPDU according to the type of PPDU indicated by the Trigger frame. The frame generation unit 303 can also generate a data signal using an MCS identified from the Trigger frame. In this case, the frame generation unit 303 uses the MCS table to be used indicated by the Trigger frame to identify the MCS to be used for generating the data signal from the MCS index contained in the Trigger frame.

[0031] The frame transmission unit 304 transmits the PPDU generated by the frame generation unit 303. The frame reception unit 305 receives frames transmitted by the other party's communication device. For example, the frame reception unit 305 receives an acknowledgment for the PPDU transmitted by the frame transmission unit 304. The frame reception unit 305 of STA110 can also receive a trigger frame from AP101.

[0032] Figure 4 shows an example of the functional configuration of the receiving communication device 100. The functional configuration in this embodiment is an example of a functional configuration realized by, for example, one or more processors executing a program stored in one or more memories. The communication device 100 may include an MCS management unit 401, a frame analysis unit 402, a data demodulation unit 403, a frame receiving unit 404, and a frame transmission unit 405. AP101 may further include a trigger generation unit 406. Note that the MCS management unit 401 operates in the same way as the MCS management unit 301, so its description is omitted.

[0033] The frame analysis unit 402 analyzes the PPDU received from the other party's communication device. For example, the frame analysis unit 402 analyzes the preamble included in the PPDU and obtains information for acquiring data from the data signal. By analyzing the preamble, the frame analysis unit 402 can obtain information indicating the standard to which the PPDU conforms. The frame analysis unit 402 can identify the configuration of the PPDU based on the standard to which the PPDU conforms. Furthermore, based on the identified PPDU configuration, the frame analysis unit 402 can obtain information indicating the MCS index corresponding to the MCS used to generate the data, information identifying the MCS table to be used to identify the MCS from the MCS index, and so on. If a standard and an MCS table are associated, the frame analysis unit 402 can identify the MCS table to be used based on the information indicating the standard to which the PPDU conforms. Using the identified MCS table, the frame analysis unit 402 can identify the MCS used to generate the data from the MCS index included in the PPDU.

[0034] The data demodulation unit 403 demodulates the data signal to acquire data. For example, the data demodulation unit 403 demodulates the data signal contained in the PPDU based on the MCS identified by the frame analysis unit 402.

[0035] The frame receiving unit 404 receives the PPDU from the other party's communication device. The frame transmitting unit 405 transmits a frame to the other party's communication device. For example, the frame transmitting unit 405 transmits an acknowledgment for the received PPDU to the other party's communication device. In addition, the frame transmitting unit 405 in AP101 may transmit a trigger frame to STA110.

[0036] The Trigger generation unit 406 generates a Trigger frame. For example, the Trigger generation unit 406 of AP101 can generate a Trigger frame when multiple STA110s are to transmit data in parallel via multi-user transmission. In the Trigger frame, the Trigger generation unit 406 can set information indicating the type of PPDU that the STA110 should use for communication and the MCS that the STA110 should use to generate the data signal. For example, the Trigger generation unit 406 can select the type of PPDU that the STA110 should use based on the standard that the STA110 supports. As an example, if STA111 supports the first and second standards, and STA112 supports the second standard, AP101 can select the second standard in order to transmit data in parallel to STA111 and STA112. The Trigger generation unit 406 can also identify the MCS that the other party's communication device can use and select the MCS to be used to generate the data signal according to the identified MCS. For example, the Trigger generation unit 406 can identify multiple MCSs that the STA110 can use based on the standards that the STA110 supports, and select an appropriate MCS from among them according to the channel conditions. The Trigger generation unit 406 can set in the Trigger frame information that identifies the MCS table that the other party's communication device should use, and an MCS index corresponding to the MCS to be used to generate the data signal.

[0037] (Examples of processes performed by communication devices during transmission) The following describes some examples of the processing flow performed by the communication device 100 in this embodiment. First, the processing flow performed when the communication device 100 performs a transmission process will be described. Since both AP101 and STA110 can transmit data, the communication device 100 in this example may be either AP101 or STA110. In this example, the communication device 100 is capable of performing communication compliant with a first standard and communication compliant with a second standard included in the IEEE802.11 standard series. That is, the communication device 100 can perform PPDU transmission processing compliant with the first standard and PPDU transmission processing compliant with the second standard. For example, the first standard may be the IEEE802.11bn standard or its successor standard, and in this embodiment, it is the IEEE802.11bn standard. The second standard may be a legacy standard for the IEEE802.11bn standard, and in this embodiment, it is the IEEE802.11be standard. Figure 5 shows an example of a processing flow executed by the communication device 100 when it performs PPDU transmission processing. This processing flow may be initiated, for example, based on the communication device 100 detecting that data has been input into its transmission buffer. First, the communication device 100 determines the type of PPDU to be used for transmission. For example, the communication device 100 determines whether to use a PPDU conforming to the first standard or a PPDU conforming to the second standard for transmission (S501). For example, the communication device 100 may determine the type of PPDU to be used for transmission based on the standard supported by the other party's communication device. As an example, if the other party's communication device supports the first standard but not the second standard, the communication device 100 may determine to use a PPDU conforming to the first standard. Alternatively, if the other party's communication device does not support the first standard but supports the second standard, the communication device 100 may determine to use a PPDU conforming to the second standard. Furthermore, if the other party's communication device supports both the first and second standards, the communication device 100 may determine that it will use a PPDU compliant with the first standard. This may enable communication using relatively advanced functions.On the other hand, if the other party's communication device supports both the first and second standards, the communication device 100 may determine that it will use a PPDU compliant with the second standard. This makes it easier for peripheral terminals supporting legacy standards to understand the communication status, potentially reducing interference. Furthermore, the communication device 100 may identify the standards supported by the other party's communication device during the procedure for establishing a connection with the other party's communication device. For example, the communication device 100 may identify the standards supported by the other party's communication device by acquiring capability information that includes information that allows for the identification of the standards supported by the other party's communication device. As an example, the communication device 100 may identify that the other party's communication device complies with the IEEE 802.11be standard by receiving a frame containing an EHT Capablities element from the other party's communication device. Also, the communication device 100 may identify that the other party's communication device complies with the IEEE 802.11bn standard by receiving a frame containing a UHR Capablities element from the other party's communication device. Furthermore, both the communication device 100 and the other party's communication device may support three or more standards included in the IEEE 802.11 standard series. In this case, the communication device 100 may perform transmission processing using a PPDU that conforms to any of the standards supported by both its own device and the other party's communication device. The following explanation uses an example that supports the first and second standards, but the communication device 100 may operate similarly even when it supports three or more standards.

[0038] If the communication device 100 determines that it will use a PPDU conforming to the first standard (YES in S501), it may generate a data signal using the MCS defined in the first standard and transmit the PPDU containing the generated data signal. At this time, the communication device 100 sets information in a first area within the PPDU to identify the MCS from the MCS index contained in the PPDU (S502). For example, the communication device 100 sets information indicating that the first MCS table defined in the first standard should be used. If each MCS table usable between the communication device 100 and the other party's communication device is assigned a unique identifier, the communication device 100 may set that identifier in the first area. Furthermore, if the MCS tables defined for each standard are different, the communication device 100 may use information indicating the standard to which the PPDU conforms as information that can identify the MCS table. For example, if the PPDU format used differs for each standard, a field for identifying the PPDU format may be used as a first area for identifying the MCS table that the receiving communication device 100 should use. The communication device 100 also sets an MCS index in a second area within the PPDU that corresponds to the MCS used by the device to generate the data signal (S503). The communication device 100 uses an MCS index based on the first MCS table specified in the first standard as the MCS index set in the second area of ​​the PPDU. The communication device 100 may include the first and second areas in the PPDU preamble. If the first standard is the IEEE 802.11bn standard, the second area of ​​the PPDU may be a 5-bit field. The communication device 100 transmits the generated PPDU (S504).

[0039] On the other hand, if the communication device 100 determines that it will use a PPDU conforming to the second standard (NO in S501), it may generate a data signal using the MCS defined in the second standard and transmit the PPDU containing the generated data signal. In this case, the communication device 100 sets information in the first area of ​​the PPDU indicating that the second MCS table defined in the second standard should be used to identify the MCS from the MCS index contained in this PPDU (S505). For example, the communication device 100 sets a value in the first area indicating that this PPDU conforms to the second standard. The communication device 100 also sets an MCS index in the second area of ​​the PPDU that corresponds to the MCS used by the device to generate the data signal (S506). The communication device 100 sets an MCS index in the second area of ​​the PPDU that is based on the second MCS table defined in the second standard. If the second standard is the IEEE 802.11be standard, the second area of ​​the PPDU may be a 4-bit field. The communication device 100 transmits the generated PPDU (S504).

[0040] (Example of processing performed by a communication device upon receiving a signal) Next, the processing flow executed by the communication device 100 when it performs reception processing will be explained. Since both AP101 and STA110 can receive data, the communication device 100 in this example may be either AP101 or STA110. In this example as well, the communication device 100 is assumed to be capable of performing communication compliant with the first standard and communication compliant with the second standard included in the IEEE802.11 standard series. That is, the communication device 100 can perform reception processing of PPDUs compliant with the first standard and reception processing of PPDUs compliant with the second standard. Figure 6 shows an example of the processing flow executed by the communication device 100 when it performs PPDU reception processing. This processing flow may be initiated, for example, based on the communication device 100 detecting that a PPDU has been input via its antenna 207.

[0041] The communication device 100 receives the PPDU (S601). The communication device 100 analyzes information such as the preamble based on the format of the received PPDU. For example, the communication device 100 can identify each area containing information to be analyzed based on the setting value of a field for identifying the format of the PPDU included in the preamble. For example, if the preamble contains information that allows for the identification of the standard to which the received PPDU conforms, the communication device 100 can identify the standard to which the PPDU conforms based on this information. Furthermore, by analyzing the first area described above, the communication device 100 can obtain information indicating the MCS table to be used to identify the MCS from the MCS index included in this PPDU. In addition, by analyzing the second area described above, the communication device 100 can obtain the MCS index.

[0042] The communication device 100 determines which MCS table to use to identify the MCS from the MCS index contained in the received PPDU (S602). For example, the communication device 100 may determine which MCS table to use based on the setting value of the first area of ​​the received PPDU. If the MCS tables specified for each standard are different, the communication device 100 may determine which MCS table to use by using information to identify the format of the PPDU or information indicating the standard to which the PPDU conforms. If the communication device 100 determines that the first MCS table should be used (YES in S602), it interprets the MCS index obtained from the second area of ​​the PPDU based on the MCS table of the first standard (S603). That is, the communication device 100 uses the first MCS table to identify the MCS corresponding to the acquired MCS index. The communication device 100 demodulates the data signal and acquires the data, assuming that the identified MCS was used in generating the data signal contained in the received PPDU (S605).

[0043] On the other hand, if the communication device 100 determines that the second MCS table should be used (NO in S602), it interprets the MCS index obtained from the second area of ​​the PPDU based on the MCS table of the second standard (S604). That is, the communication device 100 uses the first MCS table to identify the MCS corresponding to the acquired MCS index. The communication device 100 demodulates the data signal and acquires the data, assuming that the identified MCS was used in generating the data signal contained in the received PPDU (S605).

[0044] (PPDU format compliant with IEEE 802.11be standard) This section describes examples of PPDU formats used between communication devices. Figure 7(A) shows an example configuration of an EHT MU PPDU compliant with the IEEE 802.11be standard. EHT MU PPDU is an abbreviation for Extremely High Throughput Multi-user PPDU. This frame format can be an example of a PPDU frame format compliant with the second standard in this example. EHT MU PPDU can be used in downlink communication from AP101 to STA110. EHT MU PPDU can also be used when STA110 performs uplink communication using single-user communication (SU), etc. Figure 7(B) similarly shows an example configuration of an EHT TB PPDU compliant with the IEEE 802.11be standard. EHT TB PPDU is an abbreviation for Extremely High Throughput Trigger based PPDU. This frame format can also be an example of a PPDU frame format compliant with the second standard in this example. EHT TB PPDU can be used in uplink communication from STA110 to AP101, based on a trigger frame transmitted by AP101. Below, we will first describe EHT MU PPDU, and then EHT TB PPDU.

[0045] (EHT MU PPDU format) An EHT MU PPDU may consist of L-STF701, L-LTF702, L-SIG703, RL-SIG704, U-SIG705, EHT-SIG706, EHT-STF707, and EHT-LTF708. An EHT MU PPDU may contain one or more EHT-LTF708s. L-STF701 to EHT-LTF708 may be called preambles. STF is an abbreviation for Short Training Field. LTF is an abbreviation for Long Training Field. SIG is an abbreviation for Signal Field. An EHT-MU PPDU may also contain Data709 and Packet Extension710.

[0046] L-STF701 to L-SIG703 are fields designed to ensure backward compatibility with legacy standards (IEEE 802.11a / b / g / n / ac / ax, etc.). That is, communication devices compatible with legacy standards can recognize the information contained in L-STF701 to L-SIG703. L-STF701 is used for wireless frame detection, automatic gain control, timing detection, etc. Automatic gain control may be called Automatic Gain Control (AGC). L-LTF702 is used for high-precision frequency synchronization, timing synchronization, and acquisition of propagation channel information, etc. Propagation channel information may be called Channel State Information (CSI). L-SIG703 is used to notify control information such as the length of the PPDU (packet length). RL-SIG704 may be composed of multiple L-SIG703 units. For example, the presence of RL-SIG704 in a PPDU may indicate that this PPDU is a standard released after the IEEE 802.11ax standard. EHT-STF707 may be used for automatic gain control in MIMO communication. MIMO is an abbreviation for Multiple Input, Multiple Output. EHT-LTF708 may be used to estimate the MIMO channel in the receiving communication device. Data709 is a data signal. Data709 is a region containing the data to be communicated and may contain, for example, one or more MPDUs. MPDU is an abbreviation for Medium Access Control (MAC) Protocol Data Unit. The data signal in Data709 may be generated using an MCS selected by the communication device 100. Packet Extension710 may be used to provide additional reception processing time to the receiving communication device 100.

[0047] U-SIG705 contains information for the receiving communication device 100 to interpret the EHT MU PPDU. An example of the information contained in U-SIG705 is shown in Figure 16. U-SIG705 may consist of two parts: U-SIG-1 and U-SIG-2. U-SIG705 may have common parts that are independent of the standard and standard-specific parts that are dependent on the standard. For example, the five subfields included in U-SIG-1—PHY Version Identifier, Bandwidth, UL / DL, BSS Color, and TXOP—may be common parts that are independent of the standard. The PHY Version Identifier subfield may indicate information that identifies the configuration of the PHY layer as the PHY version. For example, a value of 0 may be set for a PPDU compliant with the IEEE 802.11be standard. Also, as will be described later, a value greater than 0 (for example, a value of 1) may be set for a PPDU compliant with the IEEE 802.11bn standard. Thus, the PHY Version Identifier subfield can be used to identify the standard to which the PPDU conforms, and therefore can be used as the first area in the PPDU as described above. The SIG MCS subfield in U-SIG-2 indicates the MCS index corresponding to the MCS used to generate EHT-SIG706, which follows U-SIG705.

[0048] EHT-SIG706 contains additional information for interpreting the EHT MU PPDU. While U-SIG705, mentioned above, contains standard-independent information, EHT-SIG706 can be configured flexibly according to the provisions of the standard (e.g., the IEEE 802.11be standard). Figures 8(A) to 8(C) show example configurations of EHT-SIG706 in an EHT MU PPDU used when the communication device 100 performs OFDMA transmission. OFDMA is an abbreviation for Orthogonal Frequency-Division Multiple Access. Figure 8(A) shows an example configuration of EHT-SIG706 when EHT MU PPDUs with bandwidths of 20MHz, 40MHz, and 80MHz are used. Figure 8(B) shows an example configuration of EHT-SIG706 when an EHT MU PPDU with a bandwidth of 160MHz is used. Figure 8(C) shows an example configuration of the EHT-SIG706 when an EHT MU PPDU with a bandwidth of 320 MHz is used. Figures 9(A) to 9(C) show example configurations of the EHT-SIG706 in an EHT MU PPDU used when the communication device 100 performs transmission other than OFDMA transmission. Figure 9(A) shows an example configuration of the EHT-SIG706 in an EHT MU PPDU used when the communication device 100 performs single-user (SU) transmission. Figure 9(B) shows an example configuration of the EHT-SIG706 in an EHT MU PPDU used when the communication device 100 performs multi-user transmission without using OFDMA. Figure 9(C) shows an example configuration of the EHT-SIG706 in an EHT MU PPDU used when the communication device 100 performs Sounding NDP transmission. Below, we will first explain Figure 8(A), and then explain Figures 8(B), 8(C), and 9(A)-(C) in that order.

[0049] (Example configuration of EHT-SIG for EHT MU PPDU used for OFDMA transmission) The EHT-SIG706 shown in Figure 8(A) consists of a Common field 801 and a User Specific field 802. The Common field 801 contains information that should be commonly used by one or more communication devices 100 that should receive this PPDU. The Common field 801 may include subfields for U-SIG overflow, one or two RU allocation-A, CRC, and Tail as region 803. An example of the information included in the Common field 801 is shown in Figure 17. Note that region 803 in the example configuration of the EHT-SIG706 shown in Figure 8(A) corresponds to the B0-B26+9N portion in Figure 17. For example, the B0-B16 portion in Figure 17 corresponds to the U-SIG overflow subfield in region 803. Also, region 803 in the example configuration of the EHT-SIG706 shown in Figure 8(A) does not include the B27+9N-B36+9N+9M portion in Figure 17. The portion B27+9N~B36+9N+9M in Figure 17 may be included in the configuration example of the EHT-SIG706 shown in Figure 8(B) later.

[0050] The User Specific field 802 contains information that is individually notified to each of the one or more communication devices 100 that should receive this PPDU. In the following, User may refer to the communication device 100 used by that user. For example, the area allocated to each user may refer to the area allocated to the communication device 100 used by each user. As an example, area 804 may be allocated to STA111 in Figure 1, and area 805 may be allocated to STA112. Areas 804 and 805 may each consist of two User fields, a CRC subfield, and a Tail subfield. An example of the information contained in areas 804 and 805 is shown in Figure 18. An example of the information contained in the User field in Figure 18 is shown in Figures 19 and 20. Figure 19 shows an example of the information contained in areas 804 and 805 when MU-MIMO is not used in the transmission of the PPDU. Figure 20 also shows an example of the information contained in areas 804 and 805, etc., when MU-MIMO is used in PPDU transmission. In both Figure 19 and Figure 20, a 4-bit MCS subfield is provided in the User field. The communication device 100 can use this MCS subfield to notify each of the other communication devices of the MCS index of the MCS used to generate the data signal. For example, AP101 can transmit downlink data destined for STA111 and STA112, respectively, using OFDMA with EHT MU PPDU. In this case, AP101 can notify STA111 of the MCS index corresponding to the MCS used to generate the data signal destined for STA111 by setting it in the MCS subfield included in area 804 allocated to STA111. Similarly, AP101 can notify STA112 by setting the MCS index corresponding to the MCS used to generate the data signal destined for STA112 in the MCS subfield included in area 805 allocated to STA112. The STA-ID subfields included in area 804 and area 805, respectively, are set with STA-IDs indicating STA111 and STA112.STA111 and STA112 can identify areas 804 and 805 assigned to their respective devices by detecting the STA-ID subfield in which their own device's STA-ID is set. Furthermore, STA111 and STA112 can identify the MCS used to generate the data signal destined for their own devices by the MCS index set in the MCS subfield in each of areas 804 and 805. Thus, the 4-bit MCS subfield in the User field can be used as a second area of ​​the PPDU for notifying the aforementioned MCS index.

[0051] Next, we will describe the configuration examples of the EHT-SIG706 shown in Figures 8(B) and 8(C). Figure 8(B) shows a configuration example of the EHT-SIG706 included in an EHT MU PPDU with a bandwidth of 160 MHz. This configuration example differs from the EHT-SIG706 configuration example shown in Figure 8(A) in that region 814 of the Common field 811 includes two subfields, RU Allocation-B, CRC, and Tail. Region 814 corresponds to the B27+9N~B36+9N+9M portion of Figure 17 mentioned above. In other words, the EHT-SIG706 shown in Figure 8(B) contains more information to notify the allocation of Resource Units (RUs) in order to support OFDMA transmission using an EHT MU PPDU with a bandwidth of 160 MHz. Figure 8(C) shows a configuration example of the EHT-SIG706 included in an EHT MU PPDU with a bandwidth of 320 MHz. This configuration example differs from the EHT-SIG706 configuration examples shown in Figures 8(A) and 8(B) in that it includes six RU Allocation-B subfields in region 824 of Common field 821. That is, the EHT-SIG706 shown in Figure 8(C) includes more information to indicate RU placement in order to support OFDMA transmission using an EHT MU PPDU with a bandwidth of 320 MHz.

[0052] In both the EHT-SIG706 configuration examples shown in Figure 8(B) and Figure 8(C), the configuration of the User Specific field is the same, so its explanation is omitted. That is, in both the EHT-SIG706 configuration examples shown in Figure 8(B) and Figure 8(C), the 4-bit MCS subfield in the User field can be used as a second area of ​​the PPDU for notifying the aforementioned MCS index.

[0053] (Example configuration of EHT-SIG for EHT MU PPDU used for SU transmission) An example configuration of the EHT-SIG706 shown in Figure 9(A) will be described. Figure 9(A) shows an example configuration of the EHT-SIG706 in an EHT MU PPDU used when the communication device 100 performs single-user (SU) transmission. The EHT-SIG706 shown in Figure 9(A) consists of a Common field 901 and a User Specific field 902. The Common field 901 and the User Specific field 902 may consist of a single OFDM symbol. The Common field 901 may include the subfields U-SIG overflow and Number of Non-OFDMA Users. An example of the information contained in the Common field 901 is shown in Figure 21. The B0-B16 portion in Figure 21 is the same as the B0-B16 portion in Figure 17, that is, it corresponds to the U-SIG overflow subfield in region 903. The information contained in area 903 differs from the information contained in area 803, etc., in that it includes the Number of non-OFDMA Users (B17-B19).

[0054] The User Specific field 902 may include area 904 and Padding 905. Area 904 may consist of one User field, a CRC subfield, and a Tail subfield. An example of the information contained in the User Specific field 902 is shown in Figure 22. Note that Figure 22 includes the information contained in the Common field 901 as B0-B19. Therefore, B20-B51 in Figure 22 shows the information contained in the User Specific field 902, and its contents are the same as those of the User Specific field 802 shown in Figure 18. Also, the User field (B20-B41) in Figure 22 is configured in the same way as the User field shown in Figure 19. Therefore, even when performing single-user (SU) transmission, the 4-bit MCS subfield in the User field included in the EHT MU PPDU may be used as a second area of ​​the PPDU for notifying the MCS index mentioned above.

[0055] (Example configuration of EHT-SIG for EHT MU PPDU used when performing multi-user transmission without using OFDMA) The configuration example of the EHT-SIG706 shown in Figure 9(B) will be explained. Figure 9(B) shows the configuration example of the EHT-SIG706 in an EHT MU PPDU used when the communication device 100 performs multi-user transmission without using OFDMA. The EHT-SIG706 shown in Figure 9(B) is composed of a Common field 911 and a User Specific field 912. The Common field 911 is composed in the same way as the Common field 901 in Figure 9(A). That is, the Common field 911 differs from the Common field 901 in Figure 9(A) in that the value of the Number Of non-OFDMA Users (B17-B19) subfield in Figure 21 is set to 1 or more. For example, when AP101 transmits multiple data to STA111 and STA112 respectively using MU-MIMO, the value of the Number Of non-OFDMA Users subfield is set to 1.

[0056] The User Specific field 912 comprises at least area 914 and area 915. Area 914 is configured similarly to area 904 in Figure 9(A) and includes one User field, CRC, and Tail. Area 905 also includes two User fields, CRC, and Tail. The User Specific field 912 may further include areas 916 and 917. That is, the User Specific field 912 may include User fields corresponding to each of the communication devices 100 that are destinations for multi-user transmissions. The information contained in each User field in the User Specific field 912 is the same as in Figure 20. Therefore, even when the communication device 100 performs multi-user transmissions without using OFDMA, the 4-bit MCS subfield in the User field of the PPDU can be used as a second area of ​​the PPDU for notifying the aforementioned MCS index.

[0057] (Example configuration of the EHT-SIG for the EHT MU PPDU used for Sounding NDP transmission) The configuration example of the EHT-SIG706 shown in Figure 9(C) will be explained. Figure 9(C) shows the configuration example of the EHT-SIG706 in an EHT MU PPDU used by the communication device 100 for Sounding NDP transmission. Sounding NDP is a null data packet used when channel estimation is performed between communication devices. The EHT-SIG706 shown in Figure 9(C) consists of a Common field 921. That is, the configuration example of the EHT-SIG706 shown in Figure 9(C) differs from other EHT-SIG706 in that it does not have a User Specific field. The Common field 921 consists of a region 922. An example of the information contained in region 922 is shown in Figure 23. Since Sounding NDP is a null data frame, it does not contain data signals. Therefore, the EHT MU PPDU used for Sounding NDP transmission does not contain a region corresponding to the second region of the PPDU for notifying the MCS index mentioned above.

[0058] Thus, when communication device 100 uses an EHT MU PPDU, it can use the PHY Version Identifier subfield of U-SIG705 to notify the other communication device that the PPDU conforms to the second standard. This allows the other communication device to determine that it should identify the MCS from the MCS index using the second MCS table. Furthermore, communication device 100 can use the 4-bit MCS subfield in EHT-SIG706 to notify the other communication device of the MCS index corresponding to the MCS used to generate the data signals contained in the PPDU. Note that the configuration examples and information contained in the tables used in the above explanation are illustrative. For example, other fields and subfields may be included in the above configuration examples and tables, and some fields and subfields may be omitted. Also, each field and subfield may be used to indicate other information. In addition, the names of each field and subfield may be defined differently.

[0059] (EHT TB PPDU format) This section describes EHT TB PPDU. EHT TB PPDU can be used in uplink communication from STA110 to AP101, based on a trigger frame transmitted by AP101. Figure 7(B) shows an example of the frame format of EHT TB PPDU. In Figure 7(B), the same reference numbers are used for configurations similar to those in Figure (A). As can be seen by comparing Figure 7(A) and Figure 7(B), EHT TB PPDU does not have EHT-SIG706. Also, U-SIG711 of EHT TB PPDU may contain different information than U-SIG705 in EHT MU PPDU. An example of the information contained in EHT TB PPDU is shown in Figure 24. As described above, the five fields (B0-B19) in the PHY Version Identifier subfield to the TXOP subfield of the U-SIG-1 of the EHT TB PPDU are configured in the same way as the U-SIG-1 of the EHT MU PPDU. Therefore, in the EHT TB PPDU as well, the PHY Version Identifier subfield can be used to indicate that this PPDU conforms to the second standard. On the other hand, as described above, since EHT-SIG706 does not exist in the EHT TB PPDU, it is not possible to notify the other party's communication device of the MCS index corresponding to the MCS used to generate the data signal. Therefore, in this example, when the communication device 100 transmits using the EHT TB PPDU, it generates the data signal using the MCS corresponding to the MCS index notified by the Trigger frame received prior to the transmission of this PPDU. For example, when STA111 and STA112 perform an uplink OFDMA transmission to AP101 using EHT TB PPDU, AP101 first sends a trigger frame to STA111 and STA112. In the trigger frame, AP101 notifies STA111 and STA112 of the MCS index corresponding to the MCS that each of them should use.STA111 and STA112 generate the EHT TB PPDU data signal that their respective devices transmit using the MCS corresponding to the MCS index notified to them. This configuration allows the technology to be applied to EHT TB PPDU as well. An example of a trigger frame configuration is described below.

[0060] (Trigger frame format) Figure 10 shows an example of the format of a Trigger frame. A Trigger frame is a type of MAC frame. A Trigger frame may consist of the following fields: Frame Control 1001, Duration 1002, RA 1003, TA 1004, Common Info 1005, and User Info List 1006. A Trigger frame may also include the fields Padding 1007 and FCS 1008. In a Trigger frame, Common Info 1005 and User Info List 1006 may be referred to as the MAC frame body. Frame Control 1001 contains control information such as the type of frame. For example, in the case of a Trigger frame, the Type subfield in the Frame Control field 1001 may be set to the value "01", and the Subtype subfield may be set to the value "0010". The Duration field 1002 may be used to indicate the period during which data or other communications are performed. RA 1003 may contain information indicating the receiving communication device. TA 1004 may contain information indicating the transmitting communication device. Information indicating the receiving and transmitting communication devices may include the MAC address, AID, BSSID, etc., of those devices. The Padding field 1007 may be used to adjust the length of the MAC frame. The FCS field 1008 may be used by the receiving communication device 100 to determine whether or not the MAC frame has been successfully received.

[0061] The Common Info field 1005 may include the HE / EHT / UHR P160 subfield 1009 and the Special User Info Field Flag subfield 1010. The HE / EHT / UHR P160 subfield 1009 may also be the HE / EHT P160 subfield. The HE / EHT / UHR P160 subfield 1009 can be used to indicate the type of PPDU to be transmitted based on the Trigger frame containing this subfield. For example, AP101 may use the HE / EHT / UHR P160 subfield 1009 to specify the standard that the subsequent PPDU should comply with. For instance, if the HE / EHT / UHR P160 subfield 1009 is set to 0, it indicates that an EHT TB PPDU should be transmitted. Similarly, if the HE / EHT / UHR P160 subfield 1009 is set to 1, it indicates that an HE TB PPDU should be transmitted. Furthermore, if the HE / EHT / UHR P160 subfield 1009 is set to 2, it indicates that a UHR TB PPDU should be transmitted. The values ​​of the HE / EHT / UHR P160 subfield 1009 associated with HE TB PPDU, EHT TB PPDU, and UHR TB PPDU may differ from these. STA110 can transmit using a PPDU conforming to the specified standard. The HE / EHT / UHR P160 subfield 1009 can be used to identify the MCS table that the communication device 100 should use. For example, if the value set in the HE / EHT / UHR P160 subfield 1009 indicates that an EHT TB PPDU should be transmitted, it may indicate that a second MCS table should be used. The Special User Info Field Flag subfield 1010 indicates whether the subsequent User Info List field 1006 includes a Special User Info field. For example, setting it to a value of 0 indicates that the Special User Info field may be included.

[0062] The User Info List field 1006 may contain one or more User Info fields 1011. Each User Info field 1011 corresponds to each STA 110 that should transmit a PPDU based on a Trigger frame. Each User Info field 1011 also indicates the communication parameters that should be used in the PPDU transmitted by each STA. Figure 11(A) shows an example configuration of User Info field 1011. The User Info field 1011 may contain the subfields AID12 1101, RU allocation 1102, UL FEC Coding Type 1103, UL HE / EHT-MCS 1104, and UL DCM 1105. The User Info field 1011 may also contain the subfields SS Allocation / RA-RU information 1106 and UL Target Receive Power 1107. The User Info field 1011 may also contain the subfields Reserved 1108 and Trigger Dependen User Info 1109.

[0063] The AID12 subfield 1101 indicates the identifier (AID) of the communication device 110 associated with the User Info field 1011. AID is an abbreviation for Association ID. If the value 2007 is set in the AID12 subfield 1101, it indicates that the User Info field 1011 containing this AID12 subfield is a Special User Info field. The Special User Info field will be described later. RU Allocation 1102 indicates the RU that each STA 110 should use in the EHT TB PPDU. UL FEC Coding Type 1103 indicates the Coding that each STA 110 should use in the EHT TB PPDU. For example, if the value of UL FEC Coding Type 1103 is 0, it indicates that BCC should be used. Also, if the value of UL FEC Coding Type 1103 is 1, it indicates that LDPC should be used. BCC is an abbreviation for Binary Convolutional Coding. LDPC is an abbreviation for Low Density Parity Check.

[0064] UL HE / EHT-MCS1104 indicates the MCS index that each STA110 should use to generate the data signal. Based on the value set in HE / EHT / UHR P160 subfield 1009, the STA110 can identify the MCS table to be used to identify the MCS from the MCS index shown in UL HE / EHT-MCS1104. For example, if the STA110 determines, based on the value set in HE / EHT / UHR P160 subfield 1009, that it should transmit a PPDU conforming to a second standard, it can use the second MCS table to identify the MCS from the MCS index. The STA110 generates the data signal using the identified MCS. By the STA110 generating the data signal using the specified MCS, the AP101 can demodulate the received data signal based on the MCS specified by its device and acquire the data. UL DCM1105 indicates whether STA110 should use DCM in EHT TB PPDU. DCM stands for Dual Carrier Modulation. SS Allocation / RA-RU information1106 indicates the number of spatial streams that each STA110 should use in EHT TB PPDU. UL Target Receive Power1107 indicates the received power that AP101 expects. Reserved1108 is a reserved area. Dependent User Info1109 is an optional subfield that is set based on the type of Trigger frame.

[0065] This section describes the Special User Info field. The Special User Info field is identified by the value 2007 set in the AID12 subfield 1101 of the User Info field. The Special User Info field contains information commonly used by the STA100 receiving this Trigger frame, indicating the information that the STA110 should use for the U-SIG of the EHT TB PPDU. An example of the configuration of the Special User Info field is shown in Figure 11(B). The Special User Info field may include the subfields AID12 1111, PHY Version Identifier 1112, and UL Bandwidth Extension 1113. The Special User Info field may also include EHT / UHR Spatial Reuse1 1114, EHT / UHR Spatial Reuse2 1115, and U-SIG Disregard And Validate 1116. The value 2007 set in AID12 1111 indicates that this User Info field is a Special User Info field. Each of the subfields from PHY Version Identifier1112 to U-SIG Disregard And Validate1116 can be used in the U-SIG of the EHT TB PPDU shown in Figure 24. For example, if the value of PHY Version Identifier1112 is set to 0, it indicates that it is an EHT TB PPDU compliant with the IEEE 802.11be standard. Therefore, AP101 may use PHY Version Identifier1112 in the Special User Info field to specify the type of PPDU that STA110 should use. In this case, PHY Version Identifier1112 in the Special User Info field may be used to specify the MCS table to be used.

[0066] Thus, when STA110 transmits using an EHT TB PPDU, the EHT TB PPDU can be generated by AP101 based on the information specified using the Trigger frame. For example, AP101 may use the HE / EHT / UHR P160 subfield 1009 of the Trigger frame to notify STA110 that a PPDU conforming to the second standard should be used. Alternatively, AP101 may use the PHY Version Identifier 1112 in the Special User Info field of the Trigger frame to notify STA110 that a PPDU conforming to the second standard should be used. In these cases, AP101 may use these areas to notify STA110 of the MCS table that it should use. Furthermore, AP101 may use the 4-bit UL HE / EHT-MCS subfield in the User Info field to notify STA110 of the MCS index corresponding to the MCS that STA110 should use to generate the data signal. Furthermore, other areas of the Trigger frame may be used to notify STA110 that AP101 should use the second MCS table and to provide the MCS index corresponding to the MCS to be used for generating the data signal.

[0067] (UHR PPDU format) Another example of a PPDU format used between communication devices is described. Figures 12(A) and 12(B) show an example configuration of a UHR PPDU. This frame format can be an example of a PPDU frame format compliant with the first standard (IEEE 802.11bn standard) in this example. The frame format shown in Figure 12(A) may be called UHR MU PPDU. UHR MU PPDU may be an abbreviation for Ultra High Reliability Multi-user PPDU. UHR MU PPDU can be used in downlink communication from AP101 to STA110. UHR MU PPDU can also be used when STA110 performs uplink communication using single-user communication (SU), etc. The frame format shown in Figure 12(B) may be called UHR TB PPDU. UHR TB PPDU may be an abbreviation for Ultra High Reliability Trigger based PPDU. UHR TB PPDU can be used in uplink communication from STA110 to AP101, based on a trigger frame transmitted by AP101. In Figures 12(A) and 12(B), configurations similar to those in Figures 7(A) and 7(B) are given the same reference numbers and their explanations are omitted. Below, the format of the PPDU of the first standard will be explained, focusing on the differences from the format of the PPDU of the second standard.

[0068] A UHR MU PPDU may consist of L-STF701, L-LTF702, L-SIG703, RL-SIG704, U-SIG705, UHR-SIG1201, UHR-STF1202, and UHR-LTF1203. A UHR MU PPDU may contain one or more UHR-LTF1203. In Figure 12, L-STF701 to UHR-LTF1203 may be called a preamble. A UHR MU PPDU may also contain Data709 and Packet Extension710. UHR-STF1202 and UHR-LTF1203 may be configured similarly to EHT-STF707 and EHT-LTF708, respectively, or they may be configured differently. The UHR MU PPDU is not limited to the configuration shown in Figure 12(A). For example, some of the fields included in Figure 12(A) may be omitted, while other fields may be included.

[0069] The U-SIG705 in UHR MU PPDU may have at least some common components with the U-SIG705 in EHT MU PPDU shown in Figure 16. For example, the five subfields from the PHY Version Identifier subfield to the TXOP subfield (B0-B19) may be configured in the same way as in Figure 16. Here, as mentioned above, the PHY Version Identifier subfield may be used to identify the standard to which the PPDU conforms. For example, a value of 0 may be set for EHT MU PPDU, and a value of 1 may be set for UHR MU PPDU. If the value set in the PHY Version Identifier subfield is 0, the receiving communication device 100 may analyze the information contained in the received PPDU based on the EHT MU PPDU format. Also, if the value set in the PHY Version Identifier subfield is 1, the receiving communication device 100 may analyze the information contained in the received PPDU based on the UHR MU PPDU format. In this way, by including an area in a subfield commonly provided between different standards that indicates the standard to which the PPDU conforms, the receiving communication device 100 can identify the format and standard to be used for analyzing the information contained in the received PPDU.

[0070] The PHY Version Identifier subfield can be used as a first area of ​​the PPDU containing information to identify the MCS table that the receiving communication device 100 should use. If the MCS tables specified differ for each standard, the communication device 100 can identify the MCS table that it should use by identifying the standard to which the PPDU conforms. By utilizing a subfield that exists in the legacy standard as the first area of ​​the PPDU containing information to identify the MCS table that the receiving communication device 100 should use, it becomes unnecessary to create a new subfield. This reduces the amount of information that needs to be included in the PPDU preamble.

[0071] The Disregard and Validate subfields included in U-SIG-1 may be used as the first area of ​​the PPDU. By using the unused area in U-SIG-1 of the EHT MU PPDU to identify the MCS table that the receiving communication device 100 should use, the MCS table to be used can be flexibly notified regardless of the correspondence between the standard and the MCS table. For example, in cases where a common MCS table is used in multiple standards, or where multiple different MCS tables are used in one standard, it may be better to notify the difference (version) of the MCS table rather than the difference in the standard. In this case, the first area of ​​the PPDU may be set with identification information assigned to each MCS table. The Validate subfield or other subfields included in U-SIG-2 may also be used as the first area. If U-SIG-2 is configured differently for each standard, by using U-SIG-2 to identify the MCS table that the receiving communication device 100 should use, the first area of ​​the PPDU can be flexibly arranged to match the arrangement of other information.

[0072] The SIG MCS subfields (B9-B10) of U-SIG-2 can be set based on a first MCS table. For example, communication device 100 can use the first MCS table to set the MCS index corresponding to the MCS used to generate UHR-SIG1201 in the SIG MCS subfield. Note that the fields following U-SIG705 (EHT-SIG706 and UHR-SIG1201) may have different configurations depending on the standard. Therefore, the MCS used to generate the fields following U-SIG705 may be different for each standard, or a common MCS may be used regardless of the standard. For example, an MCS not used to generate EHT-SIG may be used as the MCS used to generate UHR-SIG. In this case, the MCS index associated with the value indicated by the SIG MCS subfield may differ for each standard, and the MCS associated with that MCS index may also differ for each standard. For example, MCSs can be used to generate fields following U-SIG705, starting with the smallest MCS index in the MCS table of each standard. On the other hand, the MCS used to generate EHT-SIG can be used as the MCS used to generate UHR-SIG. In this case, the MCS index associated with the value indicated by the SIG MCS subfield may be common regardless of the standard, and the MCS associated with that MCS index may be common regardless of the standard. For example, MCSs that are commonly defined from among the MCS tables defined in each standard may be used to generate fields following U-SIG705.

[0073] The UHR-SIG1201, like the EHT-SIG706, can be configured using different formats depending on the transmission method used for transmitting the UHR MU PPDU. For example, the UHR-SIG1201 in a UHR MU PPDU used when the communication device 100 performs OFDMA transmission may be configured similarly to or differently from the EHT-SIG706 shown in Figure 8(A). As an example, Figures 25 and 26 show examples of information contained in the User field of the UHR-SIG1201 when it is configured similarly to Figure 8(A). Figure 25 shows an example of information contained in the User field when MU-MIMO is not used for PPDU transmission. Figure 26 shows an example of information contained in the User field when MU-MIMO is used for PPDU transmission. The User field of UHR-SIG1201 shown in Figure 25 differs from the User field of EHT-SIG706 shown in Figure 19 in that the MCS subfield (B11-B15) is configured as a 5-bit area. Similarly, the User field of UHR-SIG1201 shown in Figure 26 differs from the User field of EHT-SIG706 shown in Figure 20 in that the MCS subfield (B11-B15) is configured as a 5-bit area. As will be described later, configuring the MCS subfield (B11-B15) as a 5-bit area makes it possible to assign an MCS index that uniquely identifies each MCS as defined in the IEEE 802.11bn standard.

[0074] In Figure 25, the Reserved subfield (B15) in Figure 19 is used to configure the MCS subfield (B11-B15) of UHR-SIG1201 as a 5-bit area. In this way, by using an area not used in EHT-SIG706, a 5-bit area can be reserved as the MCS subfield without affecting the arrangement of other information. Alternatively, to reserve a 5-bit area as the MCS subfield, some of the other subfields used in the User field of EHT-SIG706 may be used. Alternatively, the size of the User field may be increased to reserve a 5-bit area as the MCS subfield. In addition, the MCS subfield of UHR-SIG1201 may be set as 4 bits, with a 1-bit area provided to extend the MCS subfield. For example, the Reserved subfield (B15) mentioned above may be set as the extension area. In this case, the MCS can be associated with a combination of a 4-bit MCS subfield and a 1-bit extension subfield.

[0075] Figure 26 shows an example of using one bit from the Spatial Configuration subfield in Figure 20 to configure the MCS subfield (B11-B15) of UHR-SIG1201 as a 5-bit area. To reserve a 5-bit area for the MCS subfield, some of the other subfields used in the User field of EHT-SIG706 may be used. Alternatively, the size of the User field may be increased to reserve a 5-bit area for the MCS subfield.

[0076] Above, an example configuration of UHR-SIG1201 used when the communication device 100 uses UHR MU PPDUs with bandwidths of 20 MHz, 40 MHz, and 80 MHz for OFDMA transmission was explained using Figure 8(A). Next, an example configuration of UHR-SIG1201 used when the communication device 100 uses UHR MU PPDUs with bandwidths of 160 MHz and 320 MHz for OFDMA transmission will be explained. When the communication device 100 performs OFDMA transmission using a UHR MU PPDU with a bandwidth of 160 MHz, UHR-SIG1201 may be configured similarly to the example configuration of EHT-SIG706 shown in Figure 8(B), or it may be configured differently. For example, if UHR-SIG1201 is configured similarly to the example configuration of EHT-SIG706 shown in Figure 8(B), the User field included in UHR-SIG1201 may be configured as shown in Figure 25 or Figure 26. Furthermore, when the communication device 100 performs OFDMA transmission using a UHR MU PPDU with a bandwidth of 320 MHz, the UHR-SIG1201 may be configured similarly to the configuration example of the EHT-SIG706 shown in Figure 8(C), or it may be configured differently. For example, when the UHR-SIG1201 is configured similarly to the configuration example of the EHT-SIG706 shown in Figure 8(C), the User field included in the UHR-SIG1201 may be configured as shown in Figure 25 or Figure 26. Therefore, when the communication device 100 uses a UHR MU PPDU for OFDMA transmission, a 5-bit MCS subfield can be secured by configuring the User field as shown in Figure 25 or Figure 26, regardless of the bandwidth of the PPDU.

[0077] The UHR-SIG1201 in a PPDU (UHR MU PPDU) conforming to the first standard used when the communication device 100 performs SU transmission may be configured in the same way as in Figure 9(A) or differently. For example, if the UHR-SIG1201 is configured in the same way as the configuration example of the EHT-SIG706 shown in Figure 9(A), the User field included in the UHR-SIG1201 may be configured as shown in Figure 25. Also, the UHR-SIG1201 in a UHR MU PPDU used when the communication device 100 performs multi-user transmission without using OFDMA may be configured in the same way as in Figure 9(B) or differently. For example, if the UHR-SIG1201 is configured in the same way as the configuration example of the EHT-SIG706 shown in Figure 9(B), the User field included in the UHR-SIG1201 may be configured as shown in Figure 26. Therefore, even when the communication device 100 performs multi-user transmission using UHR MU PPDU without using SU transmission or OFDMA, a 5-bit MCS subfield can be secured by configuring the User field as shown in Figure 25 or Figure 26.

[0078] Thus, when communication device 100 uses a UHR MU PPDU, it can use the PHY Version Identifier subfield of U-SIG705 to notify the other communication device that the PPDU conforms to the first standard. This allows the other communication device to determine that it should use the first MCS table to identify the MCS from the MCS index. Alternatively, communication device 100 may use other areas of the preamble to notify the other communication device that the first MCS table should be used. For example, communication device 100 may use an area included in U-SIG705, which is commonly used with PPDUs conforming to the second standard, to notify the other communication device that the first MCS table should be used and that the PPDU conforms to the first standard. Furthermore, communication device 100 may use the 5-bit MCS subfield in UHR-SIG1201 to notify the other communication device of the MCS index corresponding to the MCS used to generate the data signals contained in the PPDU. Furthermore, the communication device 100 may use other areas of the preamble to notify the other party's communication device of the MCS index corresponding to the MCS used to generate the data signal. For example, the communication device 100 may use any area included in UHR-SIG1201, which can be flexibly configured in the standard to which the PPDU conforms, to notify the other party's communication device of the MCS index corresponding to the MCS used to generate the data signal.

[0079] (UHR TB PPDU format) This section describes UHR TB PPDU. As shown in Figure 12(B), UHR TB PPDU, like EHR TB PPDU, does not have UHR-SIG1201. Therefore, similar to EHR TB PPDU, the communication device 100 generates the data signal using the MCS corresponding to the MCS index notified by the Trigger frame received prior to the transmission of the UHR TB PPDU. By configuring it in this way, this technology can also be applied to UHR TB PPDU. Note that the U-SIG711 of UHR TB PPDU may have the same configuration of the PHY Version Identifier subfield to TXOP subfield (B0-B19) as the U-SIG705 of UHR MU PPDU shown in Figure 24. In addition, the value of the PHY Version Identifier subfield may be set to information indicating the PHY version corresponding to the IEEE 802.11bn standard. For example, the value of the PHY Version Identifier subfield may be set to 1. As a result, even in the case of a UHR TB PPDU, the communication device 100 can use the PHY Version Identifier subfield to notify the other party's communication device that this PPDU conforms to the first standard.

[0080] (Trigger frame format) This section describes the trigger frame that prompts the transmission of a UHR TB PPDU. The format of the trigger frame that prompts the transmission of a UHR TB PPDU may be configured similarly to the frame format shown in Figure 10, or it may be configured differently. If the trigger frame is configured similarly to the frame format shown in Figure 10, the value of the HE / EHT / UHR P160 subfield 1009 may be set to a value indicating that a UHR TB PPDU should be transmitted. For example, the value of the HE / EHT / UHR P160 subfield 1009 may be set to 2. This notifies the STA110 that it should transmit using a UHR TB PPDU. In this way, the STA110 can determine the format and standard of the PPDU that it should use based on the value of the HE / EHT / UHR P160 subfield 1009 contained in the received trigger frame.

[0081] The HE / EHT / UHR P160 subfield 1009 can be used as primary information to identify the MCS table that STA110 should use. If the MCS tables specified in each standard differ, STA110 can determine that it should use the primary MCS table by specifying that its device should use UHR TB PPDU. In this way, by utilizing subfields that exist in legacy standards to notify primary information, it becomes unnecessary to add new subfields to the Trigger frame or to define new types of Trigger frames.

[0082] AP101 may also notify the first information using the Special User Info field. As shown in Figure 11(B), the Special User Info field includes the PHY Version Identifier subfield 1112. As described above, the PHY Version Identifier subfield 1112 can be used to specify the type of PPDU that STA110 should use for transmission. For example, if the value of the PHY Version Identifier subfield 1112 is set to 0, it may indicate that an EHT TB PPDU should be used. Also, if the value of the PHY Version Identifier subfield 1112 is set to 1, it may indicate that a UHR TB PPDU should be used. In this way, AP101 can use the PHY Version Identifier subfield 1112 to notify STA110 of the standard to which the PPDU it should use conforms, as well as the MCS table that STA110 should use.

[0083] Areas commonly used by multiple STA110s, such as the Common Info field 1005 or other subfields of the Special User Info field in the Trigger frame, may be used to notify the first information. For example, if a reserved area exists in the Common Info field 1005 or the Special User Info field, the first information may be notified using this reserved area. By using unused areas to identify the MCS table that the receiving communication device 100 should use, the MCS table to be used can be flexibly notified regardless of the correspondence between the standard and the MCS table. For example, in cases where a common MCS table is used in multiple standards, or where multiple different MCS tables are used in one standard, it may be better to notify the difference (version) of the MCS table rather than the difference in the standard. In this case, identification information assigned to each MCS table may be set as the first information. If no reserved area exists in the Common Info field 1005 or the Special User Info field, other subfields included in these fields may be repurposed to notify the first information. Additionally, a new subfield may be added to notify the first information, and a new type of Trigger frame may be defined that includes an area for notifying the first information.

[0084] AP101 may use the User Info field 1011 of the Trigger frame to notify STA110 of second information indicating the MCS corresponding to the MCS to be used. In this case, a 5-bit area may be provided in the User Info field 1011 as a subfield indicating the MCS index. Figure 11(C) shows an example of the configuration of the User Info field 1011. In Figure 11(C), configurations similar to those in Figure 11(A) are given the same reference number and their explanation is omitted. That is, the User Info field 1011 in the Trigger frame of Figure 11(C) differs from the User Info field 1011 in Figure 11(A) in that it includes a 5-bit UL UHR-MCS1110. By configuring the UL UHR-MCS1110 as a 5-bit area, it becomes possible to assign an MCS index to each of the MCSs defined in the IEEE802.11bn standard. In Figure 11(C), the UL DCM subfield 1105 in Figure 11(A) is used to configure the UL UHR-MCS1110 as a 5-bit area. However, other subfields may be used to configure the UL UHR-MCS1110 as a 5-bit area. For example, the Reserved subfield 1108 may be used. Alternatively, the UL UHR-MCS1110 may be configured as 4 bits, with the UL DCM subfield 1105 and other areas used as a 1-bit extension area for notifying the MCS. In this case, the MCS can be associated with a combination of the 4-bit UL UHR-MCS1110 and the 1-bit extension area.

[0085] Thus, when STA110 transmits using UHR TB PPDU, AP101 can use a Trigger frame to notify STA110 that it should use a first MCS table and the MCS index of the MCS to be used to generate the data. For example, AP101 can use the HE / EHT / UHR P160 subfield 1009 of the Trigger frame to notify STA110 that it should use a PPDU conforming to a first standard. Alternatively, AP101 may use the PHY Version Identifier 1112 of the Special User Info field of the Trigger frame to notify STA110 that it should use a PPDU conforming to a first standard. These fields are areas in the MAC frame body of the Trigger frame that are commonly used for multiple STA110s. AP101 can use these areas to notify STA110 that it should use a first MCS table. Furthermore, AP101 can use the 5-bit UL UHR-MCS subfield in the User Info field to notify STA110 of the MCS index corresponding to the MCS that STA110 should use to generate the data signal.

[0086] (MCS table structure) This document describes the configuration examples of the first MCS table specified in the first standard and the second MCS table specified in the second standard. The MCS table is a table that shows the correspondence between MCSs that can be used by the communication device 100 and MCS indices that uniquely identify those MCSs within the MCS table. The MCS table may be composed of MCS indices (MCS index), modulation schemes, and coding rates. An example of the configuration of the second MCS table specified in the second standard (IEEE 802.11be standard) may be the MCS table shown in Figure 15, for example. The second MCS table may have other configurations. An example of the configuration of the first MCS table specified in the first standard (IEEE 802.11bn standard) is shown in Figure 27. The first MCS table shown in Figure 27 differs from the first MCS table in that it includes four additional MCSs: QPSK with a coding rate of 2 / 3, 16-QAM with a coding rate of 2 / 3, 16-QAM with a coding rate of 5 / 6, and 256-QAM with a coding rate of 2 / 3. Furthermore, the addition of these four MCSs results in a difference in the mapping between MCSs and MCS indices between the first and second MCS tables. For example, in the second MCS table, the MCS for the combination of 4096-QAM and a coding rate of 5 / 6 is assigned an MCS index value of 13. On the other hand, in the first MCS table, the MCS for the combination of 4096-QAM and a coding rate of 5 / 6 is assigned an MCS index value of 17. This is because, in the first MCS table, the table has been restructured so that the higher the data rate of each MCS, including the four added MCSs, the larger the MCS index value assigned. The data rate shown in Figure 27 is an example of the data rate when 26 RU tones are assigned to STA110 and a PPDU consisting of OFDM symbols with a guard interval length of 0.8 μsec is transmitted in a single stream.

[0087] The four MCSs added in this example are MCSs that were not used in the legacy standard. Enabling the use of these MCSs can increase the throughput of the BSS. For example, suppose that in a communication device using the second MCS table, if a transmission using an MCS with a QPSK and coding rate of 3 / 4 fails, the next transmission uses an MCS with a QPSK and coding rate of 1 / 2. In contrast, if a transmission using an MCS with a QPSK and coding rate of 3 / 4 fails in a communication device using the first MCS table, the next transmission can use an MCS with a QPSK and coding rate of 2 / 3. This allows the use of an MCS with a data rate 1.5 times higher. In this way, enabling the use of MCSs that were not used in the legacy standard can increase the overall throughput of the BSS.

[0088] Furthermore, as shown in Figure 27, by reconfiguring the first MCS table based on the data rate of each MCS, the communication device 100 can efficiently select an appropriate MCS by referring to the first MCS table according to the conditions of the propagation channel. For example, suppose an MCS index is assigned to an added MCS regardless of its data rate. In this case, the process of selecting the next MCS to use in the communication device 100 if transmission fails in the most recent communication may become complicated. For example, the communication device 100 may identify the data rate of each MCS, search for an MCS with a lower data rate, and decide which MCS to use. On the other hand, as shown in Figure 27, by assigning an MCS index to each MCS, including the added MCS, based on its data rate, the communication device 100 can select an MCS corresponding to the MCS index with one smaller value in the event of a transmission failure. In this way, the communication device 100 can efficiently select an MCS based on the MCS index in the MCS table.

[0089] Here, by assigning an MCS index based on the data rate to each MCS, including the added MCS, different MCSs will be assigned to the same MCS index between the first MCS table and the second MCS table. For example, in the second MCS table, the value of MCS index 13 is assigned to an MCS with a combination of 4096-QAM and a coding rate of 5 / 6. On the other hand, in the first MCS table, the value of MCS index 13 is assigned to an MCS with a combination of 256-QAM and a coding rate of 5 / 6. Therefore, if the communication device 100 supports both the first and second standards, it may not be possible to uniquely identify an MCS from the value of the MCS index. Accordingly, in this example, the communication device 100 first identifies the MCS table to be used to identify the MCS based on the standard to which the PPDU conforms, and then identifies the MCS associated with the MCS index obtained based on the identified MCS table.

[0090] Furthermore, the addition of multiple MCSs increases the number of required MCS indices. For example, while the maximum MCS index in Figure 15 was 13 when QPSK-DCM was excluded, the maximum MCS index in Figure 27 is 17. If the maximum MCS index is 13, it can be represented with 4 bits, but if the maximum MCS index is 16 or more, 5 bits or more are required. Therefore, the communication device 100 in this example is configured to have a 5-bit area for indicating the MCS index. With this configuration, the communication device 100 can appropriately notify the other communication device of the MCS it has used, and can select and communicate from a variety of MCSs according to the propagation channel conditions. As a result, the communication device 100 corresponding to the first standard can improve the overall BSS throughput using the added MCSs. Note that the first MCS table does not necessarily have to include all four MCSs mentioned above, and other MCSs may be added.

[0091] Figure 28 shows another example of the configuration of the first MCS table used in the first standard. This example shows a case where MCS can be used in combination with QPSK, 16-QAM, 64-QAM, 256-QAM, 1024-QAM, and 4096-QAM, and coding rates of 1 / 2, 2 / 3, 3 / 4, 5 / 6, and 7 / 8, respectively. In this case, each MCS is sorted in ascending order of the number of multi-level modulation schemes, and among MCSs with the same number of multi-level modulation schemes, they are sorted in ascending order of coding rate. Then, the smallest MCS index is associated with each sorted MCS, starting from the beginning. In Figure 28, the maximum value of the MCS index is 31, so the communication device 100 can notify the other communication device of the MCS index used using a 5-bit area. According to the configuration in Figure 28, a wider variety of MCS can be used, so the communication device 100 can finely switch MCS according to the conditions of the propagation channel. This could potentially increase the overall throughput of the BSS.

[0092] Figure 29 shows another example of the configuration of the first MCS table used in the first standard. In this example, the assignment of MCS indices to each MCS in the second MCS table is maintained, while an MCS index is assigned to each additional MCS. For example, each additional MCS may be associated with an MCS index not used in the second MCS table. As an example, the MCS with QPSK and coding rate 2 / 3 is assigned an MCS index value of 14. Also, the MCS with 16-QAM and coding rate 2 / 3, 16-QAM and coding rate 5 / 6, and 256-QAM and coding rate 2 / 3 are assigned MCS index values ​​from 16 to 18, respectively. According to this example configuration, different MCS indices are not assigned to the same MCS between the first and second MCS tables. Therefore, a communication device 100 that supports both communication using the first standard and communication using the second standard can uniquely identify the MCS based on the value of the MCS index.

[0093] Figure 30 shows another example of the configuration of the first MCS table used in the first standard. In this example, while maintaining the assignment of MCS indices to MCS in the second MCS table, an MCS index is assigned to each additional MCS. In this example, the additional MCS is assigned the same MCS index as the other MCS, and the added MCS is identified by an extended bit. For example, the MCS with QPSK and coding rate 2 / 3 is assigned an MCS index value of 1. Also, the MCS with 16-QAM and coding rate 2 / 3, 16-QAM and coding rate 5 / 6, and 256-QAM and coding rate 2 / 3 are assigned MCS index values ​​of 3, 4, and 8, respectively. These MCS indices are all MCS indices that are assigned to other MCS in the second MCS table. Therefore, the communication device 100 cannot uniquely identify the associated MCS using only the MCS index. Therefore, an extension bit is provided to identify these MCSs. For example, the Reserved subfield or part of the Spatial Configuration subfield of the User field of UHR-SIG1201 may be used as an extension bit. Alternatively, the UL DCM subfield 1105 of the User Info field 1011 may be used as an extension bit. For example, a value of 1 may be set as the extension bit to identify an added MCS. In this way, the communication device 100 can uniquely identify an MCS by using a 4-bit MCS index in combination with a 1-bit extension bit.

[0094] The first MCS tables that can be used in the first standard are not limited to the examples above. For example, in Figure 27, lower data rates may be assigned larger MCS index values. Some of the MCS included in Figure 28 may be deleted, and other MCS may be added. In Figure 29, the MCS indexes assigned to the added MCS may be configured to be contiguous. MCS not included in these tables may be added, and some of the MCS included in these tables may be deleted.

[0095] (Sequence between communication devices) The following describes an example sequence of data exchange between communication devices configured as described above. Figure 13 shows an example sequence of downlink data communication between AP101 and STA111 and STA112. AP101 and each of STA111 and STA112 are assumed to support both communication using the first standard and communication using the second standard. Furthermore, AP101 is assumed to identify the standard that each STA supports in the procedure for establishing a connection with each of STA111 and STA112. In addition, AP101 is assumed to identify that each of STA111 and STA112 has the capability to use the first MCS table and the second MCS table, and to identify the MCS that each STA can use.

[0096] First, when AP101 detects that data destined for STA111 and STA112 has been accumulated in its transmit buffer, it initiates channel access. AP101 also determines the type of PPDU to use based on the data's destination. For example, AP101 may determine to use a UHR MU PPDU based on the fact that both STA111 and STA112 support communication using the first communication standard. AP101 also determines the MCS to generate the data signal for each STA. For example, AP101 may determine which MCS to use to generate a data signal destined for STA111 from among the MCS available for STA111. AP101 may also determine which MCS to use to generate a data signal destined for STA112 from among the MCS available for STA112. AP101 then generates a UHR MU PPDU containing the generated data signal. For example, AP101 may set a value corresponding to the PHY version of the first standard in the PHY Version Identifier subfield of U-SIG705 of UHR-MU PPDU. AP101 may also set the MCS index value in the 5-bit MCS subfield of the User field associated with STA111 of UHR-SIG1201. In this case, the MCS index value may be the MCS index value in the first MCS table corresponding to the MCS used to generate the data signal destined for STA111. Similarly, AP101 may set the MCS index value in the 5-bit MCS subfield of the User field associated with STA112 of UHR-SIG1201. In this case, the MCS index value may be the MCS index value assigned in the first MCS table to the MCS used to generate the data signal destined for STA112. Upon successful access to the channel, AP101 sends the generated UHR MU PPDU1301.

[0097] When STA111 and STA112 receive a PPDU1301 transmitted by AP1301, they perform reception processing based on the information contained in the preamble signal. For example, STA111 and STA112 can determine that the received PPDU1301 is a UHR MU PPDU based on the value set in the PHY Version Identifier subfield of the U-SIG705 of the received PPDU1301. Also, STA111 and STA112 can identify the MCS used to generate the data signal based on the value in the MCS subfield of the User field associated with their own device in STA111 of UHR-SIG1201. For example, STA111 and STA112 can determine from the PHY Version Identifier subfield that a first MCS table should be used. Then, using the first MCS table, STA111 and STA112 can identify the MCS from the MCS index shown in the MCS subfield of the User field associated with their own device. Based on the identified MCS, STA111 and STA112 demodulate the data signal destined for their own devices and acquire the data. STA111 and STA112 each send acknowledgments 1302 and 1303, respectively, to AP101, indicating that the data has been successfully demodulated. These acknowledgments may be Block ACK frames or ACK frames. AP101 completes the transmission process based on receiving acknowledgments from both STA111 and STA112.

[0098] Figure 14 shows an example sequence when uplink data is communicated between AP101 and STA111 and STA112. First, AP101 obtains the data storage status from STA111 and STA112, respectively. For example, AP101 may notify STA111 and STA112 to report the data storage status by sending a Buffer Status Report Poll frame 1401. STA111 and STA112 report the data storage status to AP101. For example, STA111 and STA112 may notify Buffer Status Reports 1402 and 1403 in response to the Buffer Status Report Poll frame 1401. Based on the data storage status of STA111 and STA112, AP101 sends a Trigger frame 1404. For example, if STA111 and STA112 are each storing data, AP101 may send a Trigger frame 1404 addressed to STA111 and STA112. In the trigger frame 1404, AP101 may specify the type of PPDU that STA111 and STA112 should use and the MCS that should be used to generate the data signal. For example, AP101 may determine that UHR TB PPDU should be used based on the fact that both STA111 and STA112 support communication using the first standard. In this case, AP101 may notify STA111 and STA112 that UHR TB PPDU should be used using the HE / EHT / UHR P160 subfield 1009 of the trigger frame 1404. AP101 may select the MCS that STA111 should use to generate the data signal from among the MCS available to STA111. AP101 may also select the MCS that STA112 should use to generate the data signal from among the MCS available to STA112. AP101 may notify STA111 and STA112 of the MCS that they should use to generate data signals using the UL UHR-MCS subfield 1110 of the User Info field 1011 of the Trigger frame 1404. At this time, AP101 uses the first MCS table to identify the MCS index to be notified.Upon receiving Trigger frame 1404, STA111 and STA112 identify the type of PPDU to be used for transmission and the MCS to be used to generate the data signal. For example, STA111 and STA112 may determine that a UHR TB PPDU should be used based on the value set in the HE / EHT / UHR P160 subfield 1009 of Trigger frame 1404. Alternatively, STA111 and STA112 may determine the MCS to be used to generate the data signal based on the MCS index set in the UL UHR-MCS subfield 1110 of the User Info field 1011 assigned to their respective devices. At this time, STA111 and STA112 use a first MCS table to identify the MCS associated with the MCS index. STA111 and STA112 each transmit UHR TB PPDUs 1405 and 1406. The data signal contained in UHR TB PPDU 1405 is generated using the MCS identified by STA111. The data signal contained in UHR TB PPDU 1406 is generated using the MCS identified by STA112. AP101 processes the received UHR TB PPDU 1405 and 1406 respectively and sends an acknowledgment 1407 indicating that the reception process was successful. Based on the fact that STA111 and STA112 have received the acknowledgment from AP101, the transmission process is completed.

[0099] As described above, according to this embodiment, the transmitting communication device 100 includes predetermined information in the preamble of the wireless frame for identifying the MCS from the MCS index included in the wireless frame. The predetermined information includes first information that can identify the MCS table to be used to acquire the data included in the wireless frame, and second information that indicates the MCS index corresponding to the MCS used to generate the data signal. The receiving communication device 100 acquires data based on the information acquired from the preamble of the received wireless frame. The receiving communication device 100 identifies the MCS table to be used from the first information included in the preamble, and uses this MCS table to identify the MCS used to generate the data from the MCS index shown in the second information. Based on the identified MCS, the receiving communication device 100 demodulates the data signal and acquires the data. With this configuration, the MCS table used to identify the MCS from the MCS index can be matched between the transmitting communication device 100 and the receiving communication device 100. This allows the communication device 100 to flexibly use multiple standards with different parts of the MCS table, making it possible to use MCSs that were not previously used and improving the overall BSS throughput. The configuration of the frame, fields, and subfields used in this embodiment is illustrative and can be configured differently. For example, some fields and subfields in the frame may be omitted, and other fields and subfields may be included. Each frame, field, and subfield may be called by a different name. Also, some of the information contained in each field and subfield may be different. For example, other information may be included in the table used for explanation, and some information may be omitted.

[0100] The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments 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. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0101] (Summary of the embodiments) At least some of the embodiments described above can be summarized as follows: (Item 1) A communication device capable of transmitting wireless frames compliant with one or more standards included in the IEEE 802.11 standard series to other communication devices, At least a portion of the first correspondence between each of the Modulation and Coding Schemes (MCS) defined in the first standard included in the aforementioned standard and an MCS index that uniquely identifies the MCS differs from the second correspondence defined in the second standard which was standardized prior to the first standard. The aforementioned communication device is A wireless frame including a preamble signal and a data signal, The preamble signal includes first information that allows the other communication device to determine whether to use the first or second mapping to identify an MCS from the MCS index, and second information indicating the MCS index corresponding to the MCS used to generate the data signal. A generation means for generating the wireless frame, which includes a data signal generated using the MCS indicated by the first information and the second information, The system includes a transmission means for transmitting the wireless frame generated by the generation means to the other communication device, The generation means generates the wireless frame which includes the first information in the Universal Signal (U-SIG) field of the preamble signal. A communication device characterized by the following features. (Item 2) The generation means sets, as the first information, information indicating the standard to which the wireless frame conforms. A communication device as described in item 1, characterized by the features described herein. (Item 3) The generating means, as the second information, If the wireless frame conforms to the first standard, the value of the PHY Version Identifier field included in the U-SIG field is set to a value greater than 0. If the wireless frame conforms to the second standard, the value of the PHY Version Identifier field is set to 0, and the wireless frame is generated. A communication device according to item 1 or 2, characterized by the features described above. (Item 4) The first correspondence described above includes one or more of the following: a first MCS with QPSK and coding rate 2 / 3, a second MCS with 16QAM and coding rate 2 / 3, a third MCS with 16QAM and coding rate 5 / 6, and a fourth MCS with 64QAM and coding rate 2 / 3. The second correspondence described above does not include any of the first MCS, the second MCS, the third MCS, or the fourth MCS. A communication device characterized by any one of items 1 to 3. (Item 5) In the first correspondence, the value of the MCS index corresponding to a predetermined MCS is different from the value of the MCS index corresponding to the predetermined MCS in the second correspondence. A communication device characterized by any one of items 1 to 4. (Item 6) The first mapping described above is configured such that MCS with lower data rates are assigned smaller MCS index values. A communication device characterized by any one of items 1 to 5. (Item 7) The first mapping is configured such that one or more of the first MCS, the second MCS, the third MCS, and the fourth MCS are assigned an MCS index that was not used in the second mapping. A communication device as described in item 4, characterized by the features described herein. (Item 8) The generation means generates the wireless frame which includes a region consisting of five or more bits for indicating the second information. A communication device as described in any one of items 1 to 7, characterized by the features described in item 1 to 7. (Item 9) A communication device capable of receiving wireless frames from other communication devices that conform to one or more standards included in the IEEE 802.11 standard series, At least a portion of the first correspondence between each of the Modulation and Coding Schemes (MCS) defined in the first standard included in the aforementioned standard and an MCS index that uniquely identifies the MCS differs from the second correspondence defined in the second standard which was standardized prior to the first standard. The aforementioned communication device is A receiving means for receiving a wireless frame including a preamble signal and a data signal, Acquisition means for acquiring, in the preamble signal, first information that allows the communication device to identify which of the first and second mappings it should use to identify an MCS from an MCS index, and second information indicating an MCS index corresponding to an MCS used to generate the data signal, The system includes demodulation means for demodulating the data signal based on the MCS identified by the first information and the second information, The acquisition means acquires the first information from the Universal Signal (U-SIG) field in the preamble signal. A communication device characterized by the following features. (Item 10) The acquisition means acquires, as the second information, information indicating the standard to which the wireless frame conforms, The demodulation means is If the wireless frame is a wireless frame conforming to the first standard, the MCS is identified using the first mapping. If the wireless frame conforms to the second standard, the MCS is identified using the second mapping. A communication device as described in item 9, characterized by the features described herein. (Item 11) As the second piece of information, If the wireless frame conforms to the first standard, the value of the PHY Version Identifier field included in the U-SIG field is set to a value greater than 0. If the wireless frame conforms to the second standard, the value of the PHY Version Identifier field is set to 0. A communication device as described in item 9 or 10, characterized by the features described herein. (Item 12) The first correspondence described above includes one or more of the following: a first MCS with QPSK and coding rate 2 / 3, a second MCS with 16QAM and coding rate 2 / 3, a third MCS with 16QAM and coding rate 5 / 6, and a fourth MCS with 64QAM and coding rate 2 / 3. The second correspondence described above does not include any of the first MCS, the second MCS, the third MCS, or the fourth MCS. A communication device according to any one of items 9 to 11, characterized by the features described herein. (Item 13) In the first correspondence, the value of the MCS index corresponding to a predetermined MCS is different from the value of the MCS index corresponding to the predetermined MCS in the second correspondence. A communication device according to any one of items 9 to 12, characterized by the features described herein. (Item 14) The first mapping described above is configured such that MCS with lower data rates are assigned smaller MCS index values. A communication device according to any one of items 9 to 13, characterized by the features described herein. (Item 15) The first mapping is configured such that one or more of the first MCS, the second MCS, the third MCS, and the fourth MCS are assigned an MCS index that was not used in the second mapping. A communication device as described in item 12, characterized by the features described herein. (Item 16) The second piece of information is represented using five or more bits. A communication device according to any one of items 9 to 15, characterized by the features described herein. (Item 17) A communication device capable of receiving wireless frames from other communication devices that conform to one or more standards included in the IEEE 802.11 standard series, At least a portion of the first correspondence between each of the Modulation and Coding Schemes (MCS) defined in the first standard included in the aforementioned standard and an MCS index that uniquely identifies the MCS differs from the second correspondence defined in the second standard which was standardized prior to the first standard. The aforementioned communication device is A determination means for determining which MCS the other communication device should use to generate the data signals included in the wireless frame when the other communication device transmits the wireless frame, A transmission means for transmitting a Trigger frame, which includes first information that allows the other communication device to determine whether to use the first or second mapping to identify an MCS from the MCS index, and second information indicating the MCS index corresponding to the MCS determined by the determination means. The system includes receiving means for receiving a wireless frame from another communication device, which includes a data signal generated using the MCS identified by the first information and the second information, The transmitting means transmits the Trigger frame, which includes the second information in a region of the MAC frame body that is commonly used for multiple other communication devices. A communication device characterized by the following features. (Item 18) A communication device capable of transmitting wireless frames compliant with one or more standards included in the IEEE 802.11 standard series to other communication devices, At least a portion of the first correspondence between each of the Modulation and Coding Schemes (MCS) defined in the first standard included in the aforementioned standard and an MCS index that uniquely identifies the MCS differs from the second correspondence defined in the second standard which was standardized prior to the first standard. The aforementioned communication device is First information that allows the communication device to determine which of the first and second mappings it should use to identify an MCS from an MCS index, A receiving means for receiving a Trigger frame, which includes second information indicating an MCS index corresponding to the MCS to be used when the communication device generates a data signal, The system includes a transmission means for transmitting a wireless frame containing a data signal generated using the MCS identified by the first information and the second information to the other communication device, The receiving means obtains the second information from a region of the MAC frame body included in the Trigger frame that is commonly used for multiple other communication devices. A communication device characterized by the following features. (Item 19) A communication method performed by a communication device capable of transmitting wireless frames conforming to one or more standards included in the IEEE 802.11 standard series to other communication devices, At least a portion of the first correspondence between each of the Modulation and Coding Schemes (MCS) defined in the first standard included in the aforementioned standard and an MCS index that uniquely identifies the MCS differs from the second correspondence defined in the second standard which was standardized prior to the first standard. The aforementioned communication method is, A wireless frame including a preamble signal and a data signal, The preamble signal includes first information that allows the other communication device to determine whether to use the first or second mapping to identify an MCS from the MCS index, and second information indicating the MCS index corresponding to the MCS used to generate the data signal. A generation step for generating the wireless frame, which includes a data signal generated using the MCS indicated by the first information and the second information, The process includes a transmission step of transmitting the generated wireless frame to the other communication device, The generation step generates the radio frame which includes the second information in the Universal Signal (U-SIG) field of the preamble signal. A communication method characterized by the following features. (Item 20) A communication method performed by a communication device capable of receiving wireless frames from other communication devices that conform to one or more standards included in the IEEE 802.11 standard series, At least a portion of the first correspondence between each of the Modulation and Coding Schemes (MCS) defined in the first standard included in the aforementioned standard and an MCS index that uniquely identifies the MCS differs from the second correspondence defined in the second standard which was standardized prior to the first standard. The aforementioned communication method is, A receiving process that receives a wireless frame including a preamble signal and a data signal, An acquisition step of acquiring, in the preamble signal, first information that allows the communication device to identify which of the first and second mappings it should use to identify an MCS from an MCS index, and second information indicating the MCS index corresponding to the MCS used to generate the data signal, The system includes a demodulation step of demodulating the data signal based on the MCS identified by the first information and the second information, The acquisition step involves acquiring the second information from the Universal Signal (U-SIG) field in the preamble signal. A communication method characterized by the following features. (Item 21) A communication method performed by a communication device capable of receiving wireless frames from other communication devices that conform to one or more standards included in the IEEE 802.11 standard series, At least a portion of the first correspondence between each of the Modulation and Coding Schemes (MCS) defined in the first standard included in the aforementioned standard and an MCS index that uniquely identifies the MCS differs from the second correspondence defined in the second standard which was standardized prior to the first standard. The aforementioned communication method is, A determination step of determining the MCS that the other communication device should use to generate the data signals included in the wireless frame when the other communication device transmits the wireless frame, A transmission step of transmitting a Trigger frame including first information that allows the other communication device to determine whether to use the first or second mapping to identify an MCS from the MCS index, and second information indicating the MCS index corresponding to the MCS determined by the determination step, The system includes a receiving step of receiving a wireless frame from another communication device, which includes a data signal generated using the MCS identified by the first information and the second information, The transmission step involves transmitting the Trigger frame, which includes the second information in a region of the MAC frame body that is commonly used for multiple other communication devices. A communication device characterized by the following features. (Item 22) A communication method performed by a communication device capable of transmitting wireless frames conforming to one or more standards included in the IEEE 802.11 standard series to other communication devices, At least a portion of the first correspondence between each of the Modulation and Coding Schemes (MCS) defined in the first standard included in the aforementioned standard and an MCS index that uniquely identifies the MCS differs from the second correspondence defined in the second standard which was standardized prior to the first standard. The aforementioned communication method is, First information that allows the communication device to determine which of the first and second mappings it should use to identify an MCS from an MCS index, A receiving step of receiving a Trigger frame which includes second information indicating an MCS index corresponding to the MCS to be used when the communication device generates a data signal, The system includes a transmission step of transmitting a wireless frame containing a data signal generated using the MCS identified by the first information and the second information to the other communication device, The receiving step obtains the second information from a region of the MAC frame body included in the Trigger frame that is commonly used for multiple other communication devices. A communication device characterized by the following features. (Item 23) A program to cause a computer to function as one of the means of a communication device described in any one of items 1 through 18.

[0102] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of Symbols]

[0103] 101: AP, 111: STA, 112: STA, 121: Network

Claims

1. A communication device capable of transmitting wireless frames conforming to one or more standards included in the IEEE 802.11 standard series to other communication devices, At least a portion of the first correspondence between each of the Modulation and Coding Schemes (MCS) defined in the first standard included in the aforementioned standard and an MCS index that uniquely identifies the MCS differs from the second correspondence defined in the second standard which was standardized prior to the first standard. The aforementioned communication device is A wireless frame including a preamble signal and a data signal, The preamble signal includes first information that allows the other communication device to determine whether to use the first or second mapping to identify an MCS from the MCS index, and second information indicating the MCS index corresponding to the MCS used to generate the data signal. A generation means for generating the wireless frame, which includes a data signal generated using the MCS indicated by the first information and the second information, The system includes a transmission means for transmitting the wireless frame generated by the generation means to the other communication device, The generation means generates the wireless frame which includes the first information in the Universal Signal (U-SIG) field of the preamble signal. A communication device characterized by the following features.

2. The generation means sets, as the first information, information indicating the standard to which the wireless frame conforms. The communication device according to feature 1.

3. The generating means, as the second information, If the wireless frame conforms to the first standard, the value of the PHY Version Identifier field included in the U-SIG field is set to a value greater than 0. If the wireless frame conforms to the second standard, the value of the PHY Version Identifier field is set to 0, and the wireless frame is generated. The communication device according to feature 1.

4. The first correspondence described above includes one or more of the following: a first MCS based on QPSK and a coding rate of 2 / 3; a second MCS based on 16QAM and a coding rate of 2 / 3; a third MCS based on 16QAM and a coding rate of 5 / 6; and a fourth MCS based on 64QAM and a coding rate of 2 / 3. The second correspondence described above does not include any of the first MCS, the second MCS, the third MCS, or the fourth MCS. The communication device according to feature 1.

5. In the first correspondence, the value of the MCS index corresponding to a predetermined MCS is different from the value of the MCS index corresponding to the predetermined MCS in the second correspondence. The communication device according to feature 1.

6. The first mapping is configured such that MCS with lower data rates are assigned smaller MCS index values. The communication device according to feature 1.

7. The first mapping is configured such that one or more of the first MCS, the second MCS, the third MCS, and the fourth MCS are assigned an MCS index that was not used in the second mapping. The communication device according to feature 4.

8. The generation means generates the wireless frame which includes a region consisting of five or more bits for indicating the second information. The communication device according to feature 1.

9. A communication device capable of receiving wireless frames from other communication devices that conform to one or more standards included in the IEEE 802.11 standard series, At least a portion of the first correspondence between each of the Modulation and Coding Schemes (MCS) defined in the first standard included in the aforementioned standard and an MCS index that uniquely identifies the MCS differs from the second correspondence defined in the second standard which was standardized prior to the first standard. The aforementioned communication device is A receiving means for receiving a wireless frame including a preamble signal and a data signal, Acquisition means for acquiring, in the preamble signal, first information that allows the communication device to identify which of the first and second mappings it should use to identify an MCS from an MCS index, and second information indicating an MCS index corresponding to an MCS used to generate the data signal, The system includes a demodulation means for demodulating the data signal based on the MCS identified by the first information and the second information, The acquisition means acquires the first information from the Universal Signal (U-SIG) field in the preamble signal. A communication device characterized by the following features.

10. The acquisition means acquires, as the second information, information indicating the standard to which the wireless frame conforms, The demodulation means is If the wireless frame is a wireless frame conforming to the first standard, the MCS is identified using the first mapping. If the wireless frame conforms to the second standard, the MCS is identified using the second mapping. The communication device according to feature 9.

11. As the second piece of information, If the wireless frame conforms to the first standard, the value of the PHY Version Identifier field included in the U-SIG field is set to a value greater than 0. If the wireless frame conforms to the second standard, the value of the PHY Version Identifier field is set to 0. The communication device according to feature 9.

12. The first correspondence described above includes one or more of the following: a first MCS based on QPSK and a coding rate of 2 / 3; a second MCS based on 16QAM and a coding rate of 2 / 3; a third MCS based on 16QAM and a coding rate of 5 / 6; and a fourth MCS based on 64QAM and a coding rate of 2 / 3. The second correspondence described above does not include any of the first MCS, the second MCS, the third MCS, or the fourth MCS. The communication device according to feature 9.

13. In the first correspondence, the value of the MCS index corresponding to a predetermined MCS is different from the value of the MCS index corresponding to the predetermined MCS in the second correspondence. The communication device according to feature 9.

14. The first mapping is configured such that MCS with lower data rates are assigned smaller MCS index values. The communication device according to feature 9.

15. The first mapping is configured such that one or more of the first MCS, the second MCS, the third MCS, and the fourth MCS are assigned an MCS index that was not used in the second mapping. The communication device according to feature 12.

16. The second piece of information is represented using five or more bits. The communication device according to feature 9.

17. A communication device capable of receiving wireless frames from other communication devices that conform to one or more standards included in the IEEE 802.11 standard series, At least a portion of the first correspondence between each of the Modulation and Coding Schemes (MCS) defined in the first standard included in the aforementioned standard and an MCS index that uniquely identifies the MCS differs from the second correspondence defined in the second standard which was standardized prior to the first standard. The aforementioned communication device is A determination means for determining which MCS the other communication device should use to generate the data signals included in the wireless frame when the other communication device transmits the wireless frame, A transmitting means for transmitting a Trigger frame, which includes first information that allows the other communication device to determine whether to use the first or second mapping to identify an MCS from the MCS index, and second information indicating the MCS index corresponding to the MCS determined by the determination means. The system includes a receiving means for receiving a wireless frame from another communication device, which includes a data signal generated using an MCS identified by the first information and the second information. The transmitting means transmits the Trigger frame, which includes the second information in a region of the MAC frame body that is commonly used for multiple other communication devices. A communication device characterized by the following features.

18. A communication device capable of transmitting wireless frames conforming to one or more standards included in the IEEE 802.11 standard series to other communication devices, At least a portion of the first correspondence between each of the Modulation and Coding Schemes (MCS) defined in the first standard included in the aforementioned standard and an MCS index that uniquely identifies the MCS differs from the second correspondence defined in the second standard which was standardized prior to the first standard. The aforementioned communication device is First information that allows the communication device to determine which of the first and second mappings it should use to identify an MCS from an MCS index, Receiving means for receiving a Trigger frame including second information indicating an MCS index corresponding to the MCS to be used when the communication device generates a data signal, The system includes a transmission means for transmitting a wireless frame containing a data signal generated using the MCS identified by the first information and the second information to the other communication device, The receiving means obtains the second information from a region of the MAC frame body included in the Trigger frame that is commonly used for multiple other communication devices. A communication device characterized by the following features.

19. A communication method performed by a communication device capable of transmitting wireless frames conforming to one or more standards included in the IEEE 802.11 standard series to other communication devices, At least a portion of the first correspondence between each of the Modulation and Coding Schemes (MCS) defined in the first standard included in the aforementioned standard and an MCS index that uniquely identifies the MCS differs from the second correspondence defined in the second standard which was standardized prior to the first standard. The aforementioned communication method is, A wireless frame including a preamble signal and a data signal, The preamble signal includes first information that allows the other communication device to determine whether to use the first or second mapping to identify an MCS from the MCS index, and second information indicating the MCS index corresponding to the MCS used to generate the data signal. A generation step for generating the wireless frame, which includes a data signal generated using the MCS indicated by the first information and the second information, The process includes a transmission step of transmitting the generated wireless frame to the other communication device, The generation step generates the radio frame which includes the second information in the Universal Signal (U-SIG) field of the preamble signal. A communication method characterized by the following features.

20. A communication method performed by a communication device capable of receiving wireless frames from other communication devices that conform to one or more standards included in the IEEE 802.11 standard series, At least a portion of the first correspondence between each of the Modulation and Coding Schemes (MCS) defined in the first standard included in the aforementioned standard and an MCS index that uniquely identifies the MCS differs from the second correspondence defined in the second standard which was standardized prior to the first standard. The aforementioned communication method is, A receiving process that receives a wireless frame including a preamble signal and a data signal, An acquisition step of acquiring, in the preamble signal, first information that allows the communication device to identify whether to use the first or second mapping to identify the MCS from the MCS index, and second information indicating the MCS index corresponding to the MCS used to generate the data signal, The system includes a demodulation step of demodulating the data signal based on the MCS identified by the first information and the second information, The acquisition step involves acquiring the second information from the Universal Signal (U-SIG) field in the preamble signal. A communication method characterized by the following features.

21. A communication method performed by a communication device capable of receiving wireless frames from other communication devices that conform to one or more standards included in the IEEE 802.11 standard series, At least a portion of the first correspondence between each of the Modulation and Coding Schemes (MCS) defined in the first standard included in the aforementioned standard and an MCS index that uniquely identifies the MCS differs from the second correspondence defined in the second standard which was standardized prior to the first standard. The aforementioned communication method is, A determination step of determining which MCS the other communication device should use to generate the data signals included in the wireless frame when the other communication device transmits the wireless frame, A transmission step of transmitting a Trigger frame including first information that allows the other communication device to determine whether to use the first or second mapping to identify an MCS from the MCS index, and second information indicating the MCS index corresponding to the MCS determined by the determination step, The system includes a receiving step of receiving a wireless frame from another communication device, which includes a data signal generated using an MCS identified by the first information and the second information, The transmission step involves transmitting the Trigger frame, which includes the second information in a region of the MAC frame body that is commonly used for multiple other communication devices. A communication device characterized by the following features.

22. A communication method performed by a communication device capable of transmitting wireless frames conforming to one or more standards included in the IEEE 802.11 standard series to other communication devices, At least a portion of the first correspondence between each of the Modulation and Coding Schemes (MCS) defined in the first standard included in the aforementioned standard and an MCS index that uniquely identifies the MCS differs from the second correspondence defined in the second standard which was standardized prior to the first standard. The aforementioned communication method is, First information that allows the communication device to determine which of the first and second mappings it should use to identify an MCS from an MCS index, A receiving step of receiving a Trigger frame including second information indicating an MCS index corresponding to the MCS to be used when the communication device generates a data signal, The system includes a transmission step of transmitting a wireless frame containing a data signal generated using the MCS identified by the first information and the second information to the other communication device, The receiving step obtains the second information from a region of the MAC frame body included in the Trigger frame that is commonly used for multiple other communication devices. A communication device characterized by the following features.

23. A program for causing a computer to function as each of the means of the communication device described in claim 1.

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