Communication apparatus, control method, and storage medium

Abstract

To provide a mechanism for preventing reduction in improvement effect of throughput by a plurality of streams.SOLUTION: A transmission unit configured to transmit an MUPPDU including a U-SIG and a specific SIG subsequent to the U-SIG in a preamble, wherein the specific SIG includes control information for specifying an MCS that is a modulation scheme and a coding rate of a data part of each of a plurality of streams, the control information being directed to one or more specific communication apparatuses, A communication apparatus is disclosed in which the control information can include first specific information, the first specific information indicates that a data portion of a first stream of the plurality of streams is modulated and coded with a first MCS and a data portion of a second stream of the plurality of streams is modulated and coded with a second MCS, and the second MCS is different from the first MCS.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] In recent years, the increase in the amount of data being communicated has led to the development of communication technologies such as wireless LANs (Local Area Networks). The IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard series is known as the main communication standard for wireless LANs. The IEEE 802.11 standard series includes standards such as IEEE 802.11a / b / g / n / ac / ax / be.

[0003] Currently, the 802.11bn TG (Task Group) is working on the successor to the IEEE802.11be standard to further improve throughput and communication reliability. The 802.11bn TG has passed through an SG (Study Group) called IEEE802.11 UHR (Ultra High Reliability).

[0004] The IEEE 802.11 standard defined MIMO (Multi-Input-Multi-Output) communication, which allows simultaneous communication using multiple streams, as a way to improve throughput starting with 11n. This has continued to be adopted in 11ac, 11ax, and 11be. Furthermore, to support multi-user communication and reduce communication latency, 11ac adopted OFDMA communication as the secondary modulation method. OFDMA stands for Orthogonal Frequency Division Multiple Access. 11ac adopted downlink-OFDMA communication, while 11ax, the next-generation standard for 11ac, adopted uplink-OFDMA communication in addition to downlink-OFDMA communication. 11bn is expected to follow this trend and adopt DL (Downlink) / UL (Uplink)-OFDMA communication.

[0005] Starting with 11ac, OFDMA communication has been used as the secondary modulation method, but the primary modulation method is adaptive modulation, which selects the appropriate modulation method from multiple modulation methods depending on the communication environment. Multi-level modulation methods have been added to the primary modulation to improve throughput, and 11be supports BPSK, QPSK, 16QAM, 64QAM, 256QAM, 1024QAM, and 4096QAM. Communication is carried out by assigning a Modulation and Coding Scheme (MCS), defined by the combination of modulation method and coding rate, to each user.

[0006] Regarding MIMO communication, DL MIMO communication has been adopted since IEEE802.11ac, and UL-MIMO is adopted in IEEE802.11ax. This has also improved UL communication capacity, and DL / UL-MIMO is expected to continue to be adopted even after IEEE802.11be.

[0007] The IEEE is currently studying many measures to improve communication reliability, in addition to improving throughput and reducing communication delays through multi-user communication. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 5436863 specification Summary of the Invention [Problem to be solved by the invention]

[0009] IEEE802.11be allows MIMO communication with up to eight streams (for single-user communication). To communicate with eight streams, eight antennas are required within each device, the AP (Access Point) and STA (STAtion). However, because the propagation paths for each of the eight streams are separate, there is a possibility that differences in propagation loss may occur. For example, since portable mobile devices such as smartphones are often held in the hand, it is possible that certain antennas may be blocked by the hand, resulting in a decrease in transmission and reception power.

[0010] IEEE802.11 employs adaptive modulation, which assigns an appropriate modulation method to each STA (each user) depending on the communication environment. In contrast, in MIMO communications, which use multiple streams for communication, the same STA is not assigned an appropriate modulation method for each stream. In other words, in MIMO communications, which use multiple streams for communication, the same modulation method and coding rate are assigned to all streams for the same STA.

[0011] For example, there is a difference in the received power between an unobstructed antenna and an antenna obstructed by a hand, resulting in a difference in the Signal-to-Noise Ratio (SNR). A stream communicating with an unobstructed antenna meets the required SNR, enabling communication without communication errors. On the other hand, a stream communicating with an antenna obstructed by a hand may not meet the required SNR, resulting in frequent communication errors. As a result, the throughput improvement effect of multiple streams is reduced.

[0012] The present invention has been made in consideration of at least one of the above-mentioned problems. One aspect of the present invention aims to provide a mechanism for preventing a decrease in the effect of improving throughput due to multiple streams. Another aspect of the present invention aims to provide a mechanism for controlling a function for assigning an appropriate modulation scheme to each stream. [Means for solving the problem]

[0013] A communication device according to one aspect of the present invention includes a transmitting means for transmitting a multi-user (MU) physical layer protocol data unit (PPDU) including a universal signal field (U-SIG) and a specific signaling information (SIG) following the U-SIG in a preamble, The specific SIG includes control information for specifying an MCS (Modulation and Coding Scheme), which is a modulation method and a coding rate of each data portion of a plurality of streams, and the control information is directed to one or more specific communication devices; The control information may include first identification information; the first identification information indicates that a data portion of a first stream among the plurality of streams is modulated and coded using a first MCS, and that a data portion of a second stream among the plurality of streams is modulated and coded using a second MCS; The second MCS is different from the first MCS. [Effects of the Invention]

[0014] According to one aspect of the present invention, it is possible to provide a mechanism for preventing a decrease in the effect of improving throughput due to multiple streams. Also, according to another aspect of the present invention, it is possible to provide a mechanism for controlling a function for assigning an appropriate modulation scheme to each stream. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 illustrates an example of a network configuration. [Figure 2] FIG. 2 illustrates an example of a hardware configuration of a communication device. [Figure 3] FIG. 10 is a sequence diagram of an example of non-trigger base communication. [Figure 4] FIG. 10 is a diagram illustrating an example of a preamble configuration for single-user communication. [Figure 5A] FIG. 10 is a diagram illustrating an example of the configuration (part 1) of MCS and stream settings for a preamble in single-user communication. [Figure 5B] FIG. 10 is a diagram illustrating an example of the configuration (part 2) of MCS stream settings for a preamble in single-user communication. [Figure 6] FIG. 10 is a diagram illustrating an example of an MCS setting table. [Figure 7] FIG. 10 is a diagram illustrating an example of MCS setting in a preamble for single-user communication. [Figure 8] FIG. 1 is a diagram illustrating an example of a preamble configuration for multi-user communication. [Figure 9] FIG. 10 is a diagram illustrating an example of the configuration of MCS stream settings for a preamble in multi-user communication. [Figure 10] FIG. 10 is a diagram illustrating an example of setting the number of streams for each user in multi-user communication. [Figure 11] FIG. 10 is a diagram illustrating an example of MCS setting in a preamble for multi-user communication. [Figure 12] FIG. 10 is a sequence diagram of an example of trigger-based communication. [Figure 13] FIG. 10 is a diagram illustrating an example of a format of a trigger frame. [Figure 14] FIG. 10 is a diagram showing another example of an MCS setting table. [Figure 15] FIG. 10 is a diagram showing an example of the configuration of capability information that an apparatus notifies to the outside in a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Although the embodiments describe a plurality of features, not all of these features are necessarily essential to the invention, and the plurality of features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0017] (Wireless communication system configuration) 1 shows the configuration of a wireless network 100 to which communication devices 101, 102, 103, and 104 according to this embodiment belong. The communication device 101 is an AP, and the communication devices 102, 103, and 104 are STAs. Each of the communication devices 101, 102, 103, and 104 can perform wireless communication in accordance with standards such as IEEE802.11ax / be / bn. Each of the communication devices 101, 102, 103, and 104 may also be in accordance with standards after IEEE802.11be. Each communication device can communicate in frequencies of the 2.4 Hz band, the 3.6 GHz band, the 5 GHz band, and the 6 GHz band, which are called millimeter waves, as well as the 45 GHz band and the 60 GHz band.

[0018] The frequency bands used by each communication device are not limited to these, and different frequency bands such as the sub-1 GHz band may be used. Furthermore, communication devices 101, 102, 103, and 104 can communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, 540 MHz, 640 MHz, 1080 MHz, and 2160 MHz. The bandwidths used by each communication device are not limited to these, and different bandwidths such as 240 MHz and 4 MHz may be used.

[0019] The communication devices 101, 102, 103, and 104 can realize multi-user (MU) communication by performing OFDMA communication conforming to standards such as IEEE802.11ax / be / bn. Multi-user communication is a communication format in which signals from multiple users are multiplexed. In OFDMA communication, some RUs (Resource Units) of a divided frequency band are assigned to each STA so that they do not overlap, and the carrier waves of each STA are orthogonal. Therefore, an AP can communicate with multiple STAs simultaneously within a specified bandwidth. Specific examples of the communication device 101 include, but are not limited to, a wireless LAN router and a personal computer (PC).

[0020] Specific examples of the communication devices 102, 103, and 104 include, but are not limited to, cameras, tablets, smartphones, PCs, mobile phones, video cameras, and headsets. The communication devices 102, 103, and 104 may also be information processing devices such as wireless chips capable of performing wireless communication in accordance with the IEEE802.11ax / be / bn standards.

[0021] 1 is configured with one AP and three STAs, the number of APs and STAs is not limited to this. For example, there may be two, four, or more STAs. In addition, in the case of single-user communication described below with reference to FIG. 3, there may be only one STA.

[0022] (AP and STA configuration) FIG. 2 shows a hardware configuration that can be commonly applied to the AP and the STA in this embodiment.

[0023] An example of the hardware configuration includes 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).

[0024] The storage unit (201) is configured with memories such as ROM and RAM, and stores various information such as programs for performing various operations described below and communication parameters for wireless communication. Note that, in addition to memories such as ROM and RAM, the storage unit (201) may also use 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. The storage unit (201) may also include multiple memories.

[0025] The control unit (202) is configured with, for example, a processor such as a CPU or MPU, an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), etc. Here, CPU is an acronym for Central Processing Unit, and MPU is an acronym for Micro Processing Unit. The control unit (202) controls the AP by executing a program stored in the storage unit (201). The control unit (202) may control the AP in cooperation with the program stored in the storage unit (201) and an OS (Operating System). The control unit (202) may also be configured with multiple processors, such as a multi-core processor, and control the AP.

[0026] The control unit 202 also controls the function unit 203 to perform predetermined processes such as AP functions, STA functions, image capture, printing, projection, etc. The function unit 203 is hardware that enables the AP to perform predetermined processes.

[0027] The input unit (204) receives various operations from the user. The output unit (205) outputs various types of information to the user. Here, the output by the output unit (205) includes at least one of display on a screen, audio output from a speaker, vibration output, etc. Note that both the input unit (204) and the output unit (205) may be implemented in a single module, such as a touch panel.

[0028] The communication unit 206 controls wireless communication conforming to the IEEE 802.11bn standard, wireless communication conforming to Wi-Fi (registered trademark), and IP (Internet Protocol) communication. Furthermore, the communication unit 206 controls an antenna 207 to transmit and receive wireless signals for wireless communication.

[0029] Although only one antenna (207) is shown in the figure for simplicity, it is assumed that multiple antennas are provided. Generally, the number of antennas (207) corresponds to the number of streams available for corresponding MIMO communication. That is, the communication unit 206 cooperates with the antenna 207 to transmit and receive UHR PPDUs, which are wireless frames conforming to the IEEE802.11bn standard. UHR PPDU is an abbreviation for Ultra High Reliablity Physical Layer Protocol Data Unit.

[0030] The name UHR was chosen for convenience, taking into account the goals and key features of the successor standard, and may be renamed once the standard is fully established. Similarly, the name IEEE 802.11bn may be renamed once the standard is fully established. Note that this specification and the accompanying claims essentially apply to all successor standards to the 802.11be standard. Furthermore, the AP 101 and STA 102 can also transmit wireless frames conforming to legacy standards that predate the IEEE 802.11bn standard. Examples of legacy standards include IEEE 802.11a / b / g / n / ac / ax / be standards.

[0031] 3 shows a communication sequence diagram for single-user communication. STA (102) sends a probe request (300) to AP (101), and AP (101) responds to STA (102) with a probe response (301). Having received the probe response (301), STA (102) sends an authentication request (302) to AP (101), and AP (101) responds to STA (102) with an authentication response (303). Having received the authentication response (303), STA (102) sends a connection request (304) to AP (101), and AP (101) responds with a connection response (305). Having sent the connection response (305), AP (101) starts a sounding protocol sequence (306) and sends a sounding NDP (Null Data PPDU) (307) to STA (102). Upon receiving the sounding NDP (307), the STA (102) transmits a CQI (Channel Quality Indication) (308) calculated based on the sounding NDP (307) to the AP (101). This CQI (308) is the result of SNR calculation. The AP (101) sets an MCS (309) based on the CQI calculation result. The MCS at this time is set for each stream based on the CQI for each stream. Then, MCS information for each stream is included in the preamble signal, and the MCS set for each stream is applied to the data frame (data portion) to perform data frame transmission (310). The configuration of the data frame generated and transmitted by the AP 101 in data frame transmission (310) will be described in detail below. Note that soundings 306 to 308 can be omitted. If omitted, the AP (101) can determine the MCS for each stream based on past communication performance.

[0032] Figure 4 shows an example of the configuration (400) of a preamble signal and data during single-user MIMO communication. Figure 4 shows an example of a UHR MU (Multi-User) PPDU used in single-user MIMO communication. UHR stands for Ultra High Reliablity.

[0033] The UHR MU PPDU shown in FIG. 4 includes a Short Training Field (STF), a Long Training Field (LTF), a Signal Field (SIG), and a data field.

[0034] As shown in FIG. 4, the beginning of the PPDU contains L (Legacy)-STF 4001, L-LTF 4002, and L-SIG 4003 to ensure backward compatibility with the IEEE 802.11a / b / g / n standards. L-LTF 4002 is placed immediately after L-STF 4001, and L-SIG 4003 is placed immediately after L-LTF 4002. Furthermore, RL-SIG (Repeated L-SIG, RL-SIG) 4004 is placed immediately after L-SIG 4003. In the RL-SIG field, the contents of L-SIG 4003 are transmitted repeatedly. RL-SIG 4004 enables the receiver to recognize that the PPDU is compliant with the IEEE 802.11ax standard or later.

[0035] The L-STF4001 is used for detecting PHY frame signals, automatic gain control (AGC), timing detection, etc. The L-LTF4002 is used for high-precision frequency and time synchronization and for acquiring propagation channel information (CSI: Channel State Information). The L-SIG4003 is used to transmit control information including data transmission rate and PHY frame length information. Legacy devices that comply with IEEE802.11a / b / g / n / ax / be standards and devices that comply with IEEE802.11bn or later standards can decode various legacy fields.

[0036] The PPDU further includes a Universal Signal Field (U-SIG) 4005 placed immediately after the RL-SIG 4004. The U-SIG 4005 is a field for transmitting control information for each standard, which is planned to be used in common in standards from IEEE 802.11be onwards. Immediately after the U-SIG 4005 is placed a UHR-SIG1 (401). The UHR-SIG1 (401) contains control information that does not fit in the U-SIG 4005 and control information that should be transmitted to each user when performing multi-user transmission. In the example shown in Figure 4, since this is a PPDU for single-user communication, control information addressed to one user is stored. This UHR-SIG1 (401) is modulated using the MCS specified in the UHR-SIG MCS field (see Table 2 below) in the U-SIG 4005.

[0037] Next, after UHR-SIG1 (401), UHR-STF4006, an STF for UHR, and UHR-LTF4007, an LTF for UHR, are placed. UHR-LTF4007 is information used for MIMO estimation, beamforming estimation, etc. One or more UHR-LTF4007s can be placed depending on the number of MIMO antennas and whether beamforming is required. In IEEE802.11be, a maximum of eight UHR-LTF4007s can be placed.

[0038] In the UHR MU PPDU described in Fig. 4, these control fields are followed by a data field 4008 and a packet extension field 4009. The fields from L-STF 4001 to UHR-LTF 4007 of this PPDU are called the PHY preamble.

[0039] Next, U-SIG4005 included in the UHR MU PPDU explained using FIG. 4 will be explained using Table 1.

[0040] U-SIG4005 consists of two symbols (U-SIG1 and U-SIG2), each of which stores 25 bits of information. Tables 1 and 2 show the formats of U-SIG1 and U-SIG2, respectively.

[0041] The first three bits of U-SIG1 contain a subfield that stores information for distinguishing the common wireless frame version (also called PHY Clauses). On the other hand, B3 to B25 of U-SIG1 and B0 to B15 of U-SIG2 contain subfields that store control information customized for each standard.

[0042] [Table 1] [Table 2]

[0043] When a communication device generates and transmits a wireless frame conforming to the IEEE802.11bn standard based on the process described in FIG. 4, it stores a 1 in the "PHY Version Identifier" subfield in Table 1. Specifically, the communication device stores a 0 in the "PHY Version Identifier" subfield, which is the area (B0-B2) from the header portion (bit 0) to the second bit of the U-SIG. The communication device also stores a value corresponding to the bandwidth for transmitting the PPDU in the "Bandwidth" subfield, which is the 3-bit area (B3-B5) from the third bit to the fifth bit of Table 1. The communication device also stores the UHR MCS used to modulate UHR-SIG1 (401), determined based on communication conditions, in the "UHR-SIG MCS" subfield of U-SIG2. Other communication devices that receive a UHR PPDU generated and transmitted by the communication device identify the coding and modulation method for UHR-SIG1 (401) based on the UHR-SIG MCS set in the "UHR-SIG MCS" subfield. Subsequently, the other communication device assumes that UHR-SIG1 (401) has been modulated using the identified coding and modulation method, and attempts to demodulate and decode UHR-SIG1 (401).

[0044] Furthermore, when transmitting a PPDU related to single-user MIMO communication, the communication device sets "1" to the PPDU Type and Compression Mode subfield. When transmitting a PPDU related to multi-user MIMO communication, which will be described later, the communication device sets "0" or "3" to the PPDU Type and Compression Mode subfield. "0" is used when using both OFDMA and MIMO, and "3" is used when performing MIMO without OFDMA technology. The communication device also sets values ​​based on the communication parameters in the other subfields as appropriate, and transmits the UHR MU PPDU.

[0045] Next, we will explain UHR-SIG1 (401). The communication device notifies the other device of the MCS setting for each stream as follows. That is, the notification is made using a combination of the User field (407) and Special User Info field (402) for one user in UHR-SIG1 (401) (an example of first specific information). The Special User Info field (402) is a field used when setting the MCS for each stream. This will be described in detail later.

[0046] Here, in this specification, unless otherwise specified, the term "MCS per stream" or a similar term refers to the MCS applied to the data portion of each stream (see data portion 809 in FIG. 8).

[0047] UHR-SIG1 (401) consists of a Common field (403) and a User Specific field (404). The MCS setting information is transmitted using a combination of the common encoding block (405) and the first user encoding block (406) (an example of first specific information).

[0048] 5A and 5B show examples of the contents of the common encoding field (405) and the contents of the Common field (403) during single-user MIMO communication. In the example shown in Fig. 5A, the contents related to the MCS for each stream are the MCS Group (501) and the Nss (Number of spatal streams) (502), which are subfields of the User field (500). The MCS for each stream is notified by combining these contents with the contents of the Special User Info field (402) shown in Fig. 4 (an example of first specific information).

[0049] 5B shows an example of the contents of the Common field (403). In the EMCS subfield, which is the 13th bit, binary information (an example of second specific information) is set indicating whether or not an individual MCS is applied to each stream. When "0" is set, a common MCS is used for all streams, as in the previous standard 802.11bn. When "1" is set, it indicates that an individual MCS is applied to each stream, which is a feature of this embodiment. EMCS is an abbreviation for Enhancement MCS. Note that the field names are merely examples and are not limited to these.

[0050] When "0" is set in the EMCS subfield, the UHR-SIG is configured so as not to include the Special User Info field (402) described above. In this case, the MCS is indicated using the MCS subfield 503, which is a total of 4 bits, B11 to B14. In other words, when "0" is set in the EMCS field, a mechanism similar to the indication of the MCS in the data section in IEEE 802.11be can be used.

[0051] This section explains the previous MCS indication mechanism and how to specify the MCS for the data section when "0" is set in the ECMS subfield. In IEEE802.11be, MCS is defined as 1 to 16, and the 16 patterns indicate the combination of the QAM number, which is the data density per symbol, and the error correction coding rate.

[0052] By the way, it is possible to optimize the MCS for each propagation path by using a different MCS for each of the maximum eight streams. However, if you try to indicate for each stream which of MCS 1 to 16 the data is being transmitted with, you would need 32 bits (4 bits x 8 streams).

[0053] On the other hand, in this embodiment, by adopting the concept of grouping in the method shown in Fig. 6, it is possible to indicate the MCS for each stream with a total of 18 bits, consisting of 2 bits for MCS Group and 16 bits for MCS Set. Therefore, it is possible to use different MCSs for each stream while suppressing an increase in preamble overhead. A specific mechanism for this will be explained below with reference to Fig. 6 and subsequent figures. Note that if communication can be performed satisfactorily using a common MCS for all streams, the AP (101) can set EMCS to "0" and perform single-user MIMO by indicating the previous MCS common to all streams without applying the concept of grouping.

[0054] Figure 6 shows the setting table 1 (600) for the MCS Group (501). Communication is performed by changing the MCS for each stream, but since the communication targets are the same device, significant differences in path loss are unlikely to occur. For example, the required SNR difference between 1024QAM and BPSK is 20 dB or more, and it is extremely unlikely that a difference in path loss of 20 dB or more will occur between antennas in the same device. In other words, the possibility (need) of simultaneously setting an MCS corresponding to 1024QAM and an MCS corresponding to BPSK in the same device is extremely low. For this reason, group setting is divided into four groups based on the MCS closest to the required SNR for communication, and an MCS Group is assigned to a user. The MCS for each stream is selected and set from within this group. Setting from the MCS within a group is performed using the MCS Set (601), which is set in the Special User Info field (402). For example, if MCS Group (501) is 10 and MCS Set (601) is 10, 1024QAM, coding rate 3 / 4, and MCS=10 are selected.

[0055] The MCS Set for each stream is set in the Special User Info field (402). Figure 7 shows an example of MCS Set settings. This example assumes that the maximum number of streams assigned during single-user MIMO communication is "8." For example, the maximum number of streams can be extended to a number such as "16." Even in this case, by extending the Special User Info field (402) to the number of bits corresponding to the number of streams, it becomes possible to customize the MCS for each stream even when MIMO is performed with a total of 16 streams. For example, if the maximum number of streams is "16," the MCS Set can be extended to 36 bits. Note that Figures 3 to 6 illustrate the case where an AP (101) performs single-user MIMO communication with a STA (102), but this is not a limitation. Stream-by-stream customization is also possible when the STA (102) performs single-user MIMO communication with an AP (101). In this case, the roles of the sanding indicated by (306) to (308) are reversed. In other words, the STA (102) starts a sounding protocol sequence and transmits a sounding NDP to the AP (101). The AP (101) receives the sounding NDP and transmits a CQI (Channel Quality Indication) calculated based on the sounding NDP to the STA (102). The STA (102) then sets an MCS for each stream based on the received CQI, etc., and transmits a data frame for single-user MIMO communication to the AP (101).

[0056] Next, FIG. 8 shows an example of the configuration (800) of a preamble signal and data when an AP such as the communication device 101 performs multi-user MIMO communication toward multiple STAs. This is the same as for single-user communication, and overlapping content will be omitted where appropriate, with only the differences explained. In multi-user MIMO communication, the MCS for each stream is also notified using the UHR-SIG. The UHR-SIG1 (801) is composed of a Common field (803) and a User Specific field (804). Information related to the MCS setting is notified by a combination of 2Users encoding blocks (805-806) and a Special User Info2 field (802) (an example of first specific information). The 2Users encoding blocks (805-806) store User fields for two users. The Special User Info2 field (802) is placed after the User field, which stores unique information for each user who is the destination of the MIMO communication. For example, when the AP (101) performs MU communication with five STAs, five User fields and one Special User Info2 field are transmitted as the User Specific field (804). Note that in this embodiment, it is assumed that one User Encoding Block in the UHR-SIG is configured to be composed of 54 bits. As illustrated in FIG. 8, one User Encoding Block may store User fields for two users, or may store a User field for one user and one Special User Info2 field. In the latter case, it is sufficient to configure the block so that the User field for one user is placed in B0 to B21, and the Special User Info2 field is placed in B21 to B36. In addition, there may be cases where information for each user can be transmitted using 805, 806, etc., and the last User Encoding Block contains only the Special User Info2 field.In this case, the last user encoding block does not have a user field, but has a special user info2 field in B0 to B15, with the following fields B16 to B41 being padding fields.

[0057] Figure 9 shows examples (variations) of the contents of the 2 users encoding block (805). The MCS information for each stream is specified in the subfields of the user fields (900) for each of the two users. The user fields B0-B21 store information specific to user A, while the user fields B22-B43 store information specific to user B, which is different from user A. Specifically, the MCS group (901) indicates the MCS group that the corresponding user should use, just like in single-user MIMO communication. The number of streams in communication is set in the spatial configuration (902). The spatial configuration (902) stores information specifying the total number of streams and the type of stream assigned to each user.

[0058] In the example shown in FIG. 9, the MCS group (901) and spatial configuration (902) for each user are set separately.

[0059] FIG. 10 shows an example of Spatial Configuration (902). Nuser (1000) indicates the number of users. Nss1 indicates the number of streams for the first user, which corresponds to the 1st 2users encoding block (805), and Nss2 indicates the number of streams for the second user, which corresponds to the 2nd 2users encoding block (806). In this example, the total number of streams is limited to a maximum of 8, so Nuser is a maximum of 8. When Nuser is 8, the number of streams assigned to each user is 1. In the example of FIG. 10, the maximum number of streams assigned to each user is 4. The number of Nuser is calculated by counting the number of 22-bit user fields stored in the UHR-SIG shown in FIG. 9. For example, if five user fields are stored in the UHR-SIG, Nuser can be determined to be 5.

[0060] The MCS Group (901) in multi-user communication is the same as that in setting table 1 (600) shown in FIG. 6. Also, when EMCS is set to "0," the same MCS is used for all streams directed to that user using the previous MCS indication method for each user. The difference from single-user MIMO communication is as follows: Namely, the user fields (8071, 8072, ...) for each user are transmitted first, and then a Special User Info2 field (802) indicating the MCS set is provided at the end of the user fields (8071, 8072, ...). Specifically, instead of being transmitted immediately after the user fields (8071, 8072, ...) for each user, the Special User Info2 field (802) is transmitted as follows: Namely, it is commonly transmitted after the user fields (8071, 8072, ...) for all users. Each of the user fields 8071, 8072, ... contains information for two users. Therefore, the number of user fields 8071, 8072, ... is N / 2, where N is the total number of users. The Special User Info field (802) may contain information for one additional user if the total number of users N is odd. In other words, if the total number of users N is odd, the Special User Info2 field (802) in FIG. 8 contains information B0 to B21 shown in the "User field" in FIG. 9, in addition to the information shown in FIG. 11. On the other hand, if the total number of users N is even, the Special User Info2 field (802) contains only the information shown in FIG. 11, and does not contain information B0 to B21 shown in the "User field" in FIG. 9.

[0061] FIG. 11 shows an example of the Special User Info2 field (802). The MCS for each stream is determined in a similar manner to that used in single-user MIMO communication. Specifically, the MCS for each stream is indicated based on a combination of MCS Group information and MCS Set (601) information indicated in the Special User Info2 field (802) (an example of first identification information). The range of values ​​that can be set for the MCS Set (601) and their meanings are the same as those used in single-user communication. In this embodiment, as described above, it is assumed that the maximum number of streams per user is four. A communication device such as an AP determines the number of streams used for data transmission to each user (each STA) using the value of Spatial Configuration, the number of users with whom simultaneous communication is performed, and the order of the user fields. For example, in MU-MIMO communication for three users, if "001100" is set in the Spatial Configuration field, the following occurs: Four streams are assigned to the user (STA) identified in the first user field, and two streams are assigned to the user (STA) identified in the second user field. Then, two streams are assigned to the user (STA) identified in the third user field. Each STA (102 to 104) determines which User field its own STA-ID is included in. It also determines how many streams have been assigned to users before itself and how many streams have been assigned to itself, based on the value of the Spatial Configuration field and the number of users. Using this information, it determines which MCS Set in Special User Info2 to refer to. For example, the STA corresponding to the second user field in the above example (e.g., 102) recognizes that four streams have been assigned to users before itself and that two streams have been assigned to itself. It then obtains the values ​​stored in the Stream 5 MCS Set and the Stream 6 MCS Set. It then derives the MCS corresponding to the MCS Group assigned to itself.The STA corresponding to the second user field reads from the preamble that the data of each stream is transmitted using the derived MCS, and then adjusts the operating parameters of the antenna and decoder accordingly to receive the data using that MCS. This configuration change allows the STA to appropriately receive and decode the data of each stream transmitted using a different MCS.

[0062] Similarly, a method of setting MCS for each stream when performing trigger-based multi-user MIMO communication is shown. Figure 12 shows a sequence diagram of trigger-based communication. Note that Figure 13, since this is trigger-based communication, shows the sequence when performing UL multi-user MIMO. STA (102) (the same applies to STAs (103, 104), hereinafter) sends a probe request (1200) to AP (101), and the AP (101) responds to STA (102) with a probe response (1201). Upon receiving the probe response (1201), STA (102) sends an authentication request (1202) to AP (101), and the AP (101) responds to STA (102) with an authentication response (1203). Upon receiving the authentication response (1203), STA (102) sends a connection request (1204) to AP (101), and the AP (101) responds with a connection response (1205). The AP (101) that sent the connection response (1205) starts a sounding protocol sequence (1206) and sends a sounding NDP (1207) to the STA (102). The STA (102) that received the sounding NDP (1207) sends a CQI (1208) calculated based on the sounding NDP (1207) to the AP (101). This CQI (1208) is the result of SNR calculation. The AP (101) sets an MCS (1209) based on the CQI calculation result. The MCS at this time is set for each stream based on the CQI for each stream, and the AP (101) notifies the STA (102) in a trigger frame (1210). The STA (102) sets the MCS for each stream based on the information notified in the trigger frame (1210) and transmits a data frame (1211). The data frame transmitted from the STA (102) is also called a Trigger-Based (TB) Physical layer (PHY) Protocol Data Unit (PPDU).

[0063] 13 shows the structure of a trigger frame (1300). Notification of the MCS and number of streams to the user is indicated in User Info (1301).

[0064] The number of streams is set in two subfields, Starting Spatial Stream (1305) and Number of Spatial Streams (1306) in User Info (1301). The MCS is set by combining two subfields (an example of first specific information), MCS Group (1302) and UL UHR MCS (1303) in User Info (1301). The MCS is set based on the MCS setting table shown in FIG. 6. From the group set in MCS Group (1302), the UL UHR MCS (1303) sets an MCS set (1307) for each stream to determine the MCS for the data frame. For example, if MCS Group (1302) is "10" and MCS Set (1307) of UL UHR MCS (1303) is "10", a modulation method of 1024QAM, a coding rate of 3 / 4, and MCS = 10 are selected. The MCS Set (1307) is set according to the number of Spatial Streams (1306). In the example of Fig. 13, the maximum number of streams per user is set to four.

[0065] The Starting Spatial Stream subfield (1305) indicates the starting spatial stream, and stores a value obtained by subtracting 1 from the Starting Spatial Stream.

[0066] The Number Of Spatial Streams subfield (1306) indicates the number of spatial streams, and stores a value obtained by subtracting 1 from the number of spatial streams.

[0067] For example, if the number of spatial streams is 4 and the numbers of the spatial streams are represented by streams 1 to 4, the following settings are made: the Starting Spatial Stream subfield (1305) is set to 0, and the Number Of Spatial Streams subfield (1306) is set to 4.

[0068] In this case, each STA (102 to 104) identifies the location of the RU to be used based on the value included in the RU Allocation subfield (1309). Then, based on the subfields (1305) and (1306) of the SS (Spatial Stream) Allocation subfield (1309), when transmitting data using that RU, it identifies the following: That is, it identifies the number of spatial streams allocated to it and the spatial streams to be used (spatially independent transmission paths to be used). Then, each STA (102 to 104) controls itself to transmit data using one or more spatial streams allocated to it by the AP (101).

[0069] IEEE802.11be defines up to 16 MCSs, and if the number of streams in trigger-based communication is limited to a maximum of four, 16 bits are required to set MCS 1 to 16. By grouping in the same way as the method shown in Figure 6, it is possible to indicate MCS Group with 2 bits and MCS Set with 8 bits, for a total of 10 bits, which also has the advantage of reducing the overhead of the trigger frame.

[0070] In the examples shown in Figures 12 and 13, a subfield (an example of second specific information) corresponding to the above-mentioned EMCS subfield may be incorporated into Common Info (1308) of the trigger frame (1300). In this case, the EMCS subfield similarly indicates whether or not a separate MCS is applied to each stream. When "0" is set, a common MCS is used for all streams, as in the previous standard 802.11bn. When "1" is set, it indicates that a separate MCS is applied to each stream, which is a feature of this embodiment.

[0071] (Variation) In the above-described embodiment, a standard MCS group for all streams transmitted between terminals is designated, and the MCS for each stream is determined using the standard MCS group and the MCS set for each stream. The MCS set for each stream is shown in setting table 1 described in Fig. 6. MCS Group setting table 1 (600) in Fig. 6 is designed based on the technical idea of ​​grouping MCSs with similar required SNRs.

[0072] However, modifications can be made to use other concepts as the grouping criteria. FIG. 14 shows an example of MCS Group setting table 2 (1400) used in this modification instead of setting table 1. The major difference between FIG. 6 and FIG. 14 is that the coding rate for each group is common. Sharing the coding rate for each group means that the QAM corresponding to the data density superimposed on one symbol for each stream is changed, but the coding rate for error correction is not changed. By configuring the coding rate for each stream to be fixed and only the QAM to be different for each stream, as in this modification, it is not necessary to configure different hardware for error correction in the subsequent stage for each stream. This has the added advantage of enabling MIMO communication by selecting a QAM suitable for each propagation path while reducing hardware implementation costs. As with setting table 1 (600), there are four MCS groups, represented by two bits. The grouping function in this modification is also called UEQM (UnEQual Modulation). Furthermore, the grouping function that customizes both the coding rate and QAM for each stream, as explained in Fig. 6, is called UEQ-MCS (UnEQual MCS). This name is just an example.

[0073] FIG. 14 also illustrates a case where the MCS set (1401) within a group is expressed using three bits. Since modulation schemes differ within a group, setting an MCS for each stream has advantages over setting table 1 (600) when there is a large difference in the required SNR for each stream. Note that using three bits increases the overhead for transmitting information somewhat. Therefore, even in this modification, it is possible to modify the MCS set to only two bits and four patterns. While this further modification somewhat reduces the flexibility of the QAM that can be used for each stream, it makes it possible to share the error correction mechanism at the subsequent stage while balancing the suppression of overhead increases and optimization according to the propagation path.

[0074] Furthermore, capability information indicating whether UEQM or UEQ-MCS is supported can be included in the probe request, i.e., the Probe Request of the IEEE 802.11 standard, or the probe response, i.e., the Probe Response of the IEEE 802.11 standard, as described in Fig. 3. Fig. 15 shows an example of the configuration of the capability information to be notified.

[0075] Fields 1501 to 1503 store values ​​for identifying the information element as UHR Capabilities Information. UHR Capabilities Information includes multiple fields. Specifically, it includes UHR MAC Capabilities Information (not shown) that lists MAC layer capability information. It also includes UHR PHY Capabilities Information field 1504 that lists PHY layer capability information. As described above, UHR Capabilities Information stores capability information indicating whether an AP or STA supporting the IEEE 802.11bn standard supports various optional functions. The UHR PHY Capabilities Information field 1504 will be described in detail below. Field 1504-1 stores capability information indicating whether single-user MIMO and / or downlink MU-MIMO are supported. Storing "1" in field 1504-1 indicates that the UEQM function can be used (the UEQM function is supported) when performing single-user MIMO and / or downlink MU-MIMO. Storing "0" in 1504-1 indicates that the UEQM function cannot be used when performing single-user MIMO and downlink MU MIMO (the UEQM function is not supported). Storing "1" in 1504-2 indicates that the UEQM function can be used when performing trigger-based UL MU MIMO. Storing "0" in 1504-2 indicates that the UEQM function cannot be used when performing trigger-based UL MU MIMO. Note that the information shown in FIG. 15 may be configured to be included in a management frame other than a Probe Request or Probe Response. For example, the capability information shown in FIG. 15 may be included in an IEEE 802.11 standard beacon transmitted by the AP 101 and publicly announced.Also, the capability information may be included in the frames indicated by 302 to 305, i.e., the Authentication and Association Request / Association Response of the IEEE 802.11 standard. By including the capability information shown in Fig. 15 in these management frames, it is possible to notify the other device in advance of the capability information as to whether or not it supports UEQM. Note that the capability information may also be transmitted in other management frames or action frames.

[0076] The AP (101) or STA (102) that receives the capability information of the other device through the above-mentioned frame communication stores the capability information of the other device as an operating parameter. Then, when the AP (101) or STA (102) attempts to perform single-user MIMO communication or multi-user MIMO communication with a communication partner, it refers to the operating parameter and determines whether the communication partner supports UEQM. Depending on the determination, the AP (101) or STA (102) may decide whether to communicate using the grouping concept described in the above-mentioned embodiment. When transmitting data to a communication partner that does not support the UEQM function, it is sufficient to notify the preamble of the MCS common to all streams, as exemplified in 503, without applying the grouping concept, and perform data communication using the MCS common to all streams. Furthermore, when transmitting data to a communication partner that supports the UEQM function, it is sufficient to apply the grouping concept and customize the QAM used for each stream to perform data communication.

[0077] Note that while FIG. 15 illustrates the UEQM capability notification described in the modified example as an example, when the UEQ-MCS function is used, the capability information may be configured as follows. Specifically, the capability information may be configured to include information indicating whether or not the UEQ-MCS function is supported, and may be notified to the other device via a management frame or publicly announced via a beacon. In this case, too, it is possible to configure the capability information to indicate whether or not the UEQ-MCS function is supported in the case of single-user MIMO and / or downlink MU MIMO, and whether or not the UEQ-MCS function is supported when performing trigger-based UL MIMO / MU MIMO, as separate pieces of capability information. Note that the names of the fields for notifying the capability information and the bit values ​​stored therein are merely examples. In other words, the capability information may be configured to indicate to the outside whether or not the function of applying different QAMs and MCSs to streams for the same communication partner is supported, and it goes without saying that the specific transmission method may be modified.

[0078] (Other embodiments) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC or FPGA) that realizes one or more functions.

[0079] Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or a plurality of components of the above-described embodiments.

[0080] In addition, the following supplementary notes are disclosed regarding the above-described embodiment.

[0081] [Appendix 1] a transmitting means for transmitting a Multi-User (MU) PPDU (Physical Layer Protocol Data Unit) including a Universal Signal Field (U-SIG) and a specific SIG following the U-SIG in a preamble; The specific SIG includes control information for specifying an MCS (Modulation and Coding Scheme), which is a modulation method and a coding rate of each data portion of a plurality of streams, and the control information is directed to one or more specific communication devices; The control information may include first identification information; the first identification information indicates that a data portion of a first stream among the plurality of streams is modulated and coded using a first MCS, and that a data portion of a second stream among the plurality of streams is modulated and coded using a second MCS; 2. A communication device, wherein the second MCS is different from the first MCS.

[0082] [Appendix 2] A communication device having an access point function, A transmitting means for transmitting a trigger frame to each of a plurality of STAs (STAtions); receiving means for receiving TB (Trigger-Based) PPDUs (Physical layer (PHY) Protocol Data Units) transmitted in a plurality of streams from the plurality of STAs; The trigger frame includes control information for specifying an MCS (Modulation and Coding Scheme), which is a modulation method and a coding rate of each data portion of the plurality of streams, and the control information is directed to the plurality of STAs; The control information may include first identification information; the first identification information indicates that a data portion of a first stream to be transmitted by a specific STA among the plurality of streams should be modulated and encoded using a first MCS, and indicates that a data portion of a second stream to be transmitted by the specific STA among the plurality of streams should be modulated and encoded using a second MCS; 2. A communication device, wherein the second MCS is different from the first MCS.

[0083] [Appendix 3] The control information may further include second identification information, 3. The communication device according to claim 1, wherein the second specific information indicates whether modulation and coding are performed using a common MCS for the data portions of the plurality of streams.

[0084] [Appendix 4] the second identification information is binary information selectively including either a first value indicating that the data portions of the plurality of streams are modulated and coded using individual MCSs or a second value indicating that the data portions of the plurality of streams are modulated and coded using a common MCS; The communication device according to Supplementary Note 3, wherein the first identification information is included in the control information when the second identification information indicates the first value.

[0085] [Appendix 5] 5. The communication device according to claim 1, wherein the first specific information includes a combination of pieces of information stored in two or more subfields.

[0086] [Appendix 6] The communication device according to any one of Supplementary notes 1 to 5, wherein each of the first MCS and the second MCS is determined from within the first MCS group based on definition information that defines a first MCS group consisting of a plurality of different combinations of modulation schemes and coding rates, and a second MCS group consisting of a plurality of different combinations of modulation schemes and coding rates and different from the first MCS group.

[0087] [Appendix 7] The communication device described in Supplementary Note 6, wherein the combinations related to the first MCS group have required SNRs (Signal to Noise Ratios) closer to each other than the combinations related to the first MCS group and the combinations related to the second MCS group.

[0088] [Appendix 8] Each combination related to the first MCS group has the same coding rate; 7. The communication device according to claim 6, wherein each combination related to the second MCS group has the same coding rate but is different from the coding rate related to the first MCS group.

[0089] [Appendix 9] the first specific information includes a combination of information stored in a first sub-field and a second sub-field, The first subfield includes information indicating the first MCS group, The communication device according to any one of Supplementary Notes 6 to 8, characterized in that the second subfield includes information indicating which combination of the plurality of different combinations forming the first MCS group is set to which stream.

[0090] [Appendix 10] Perform multi-user MIMO (Multi Input-Multi Output) communications, The communication device described in Supplementary Note 9, characterized in that the specific SIG includes the first subfield for each of the multiple specific communication devices.

[0091] [Appendix 11] The communication device described in Supplementary Note 10, characterized in that the specific SIG includes the second subfield that is common to multiple of the specific communication devices.

[0092] [Appendix 12] A communication device having a function of STA (STAtion), A receiving means for receiving a Multi-User (MU) Physical Layer Protocol Data Unit (PPDU) including a Universal Signal Field (U-SIG) and a specific SIG following the U-SIG in a preamble; demodulation means for demodulating the data portion of the received MU PPDU based on the specific SIG; The specific SIG includes control information for specifying an MCS (Modulation and Coding Scheme), which is a modulation method and a coding rate of each data portion of a plurality of streams, and the control information is directed to one or more specific STAs including the device itself; the control information includes first identification information; the first identification information indicates that a data portion of a first stream among the plurality of streams is modulated and coded using a first MCS, and that a data portion of a second stream among the plurality of streams is modulated and coded using a second MCS; 2. A communication device, wherein the second MCS is different from the first MCS.

[0093] [Appendix 13] The communication device described in Supplementary Note 1 or 2, wherein the transmitting means further transmits to the outside a management frame including capability information indicating to the outside whether or not the device supports a function for communicating by applying different modulation methods, or different modulation methods and coding rates, to streams for the same communication partner.

[0094] [Appendix 14] A communication device, A communication device characterized by having a communication means for communicating a management frame of the IEEE802.11 standard, which includes capability information for indicating to an external device whether or not the device supports a function for applying a different modulation method, or a different modulation method and coding rate, to each of the multiple streams when communicating multiple streams to the same communication partner.

[0095] [Appendix 15] A control method for controlling communication, comprising: a transmitting step of transmitting a multi-user (MU) physical layer protocol data unit (PPDU) including a universal signal field (U-SIG) and a specific signaling information (SIG) following the U-SIG in a preamble; The specific SIG includes control information for specifying an MCS (Modulation and Coding Scheme), which is a modulation method and a coding rate of each data portion of a plurality of streams, and the control information is directed to one or more specific communication devices; The control information may include first identification information; the first identification information indicates that a data portion of a first stream among the plurality of streams is modulated and coded using a first MCS, and that a data portion of a second stream among the plurality of streams is modulated and coded using a second MCS; The control method, wherein the second MCS is different from the first MCS.

[0096] [Appendix 16] A program for causing a computer to function as the control method for a communication device described in Appendix 15. [Explanation of symbols]

[0097] 101 AP Stations 102-104

Claims

1. The present invention has a transmitting means for transmitting a MU (Multi-User) PPDU (Physical Layer Protocol Data Unit) including a U-SIG (Universal Signal field) and a specific SIG following the U-SIG in a preamble, The specific SIG includes control information for specifying a Modulation and Coding Scheme (MCS), which is a modulation method and a coding rate of each data portion of a plurality of streams, and the control information is directed to one or more specific communication devices; The control information may include first identification information, the first identification information indicates that a data portion of a first stream among the plurality of streams is modulated and encoded using a first MCS, and that a data portion of a second stream among the plurality of streams is modulated and encoded using a second MCS; The communication device, wherein the second MCS is different from the first MCS.

2. A communication device having an access point function, A transmitting means for transmitting a trigger frame to each of a plurality of STAs (STAtions); receiving means for receiving TB (Trigger-Based) PPDUs (Physical layer (PHY) Protocol Data Units) transmitted in a plurality of streams from the plurality of STAs; The trigger frame includes control information for specifying a Modulation and Coding Scheme (MCS), which is a modulation method and a coding rate of a data portion of each of the plurality of streams, and the control information is directed to the plurality of STAs; The control information may include first identification information, the first specification information indicates that a data portion of a first stream to be transmitted by a specific STA among the plurality of streams should be modulated and encoded using a first MCS, and indicates that a data portion of a second stream to be transmitted by the specific STA among the plurality of streams should be modulated and encoded using a second MCS; The communication device, wherein the second MCS is different from the first MCS.

3. The control information may further include second identification information, 3. The communication device according to claim 1, wherein the second specific information indicates whether modulation and coding are performed using a common MCS for the data portions of the plurality of streams.

4. the second specification information is binary information selectively including either a first value indicating that the data portions of the plurality of streams are modulated and coded using individual MCSs or a second value indicating that the data portions of the plurality of streams are modulated and coded using a common MCS; The communication device according to claim 3 , wherein the first specifying information is included in the control information when the second specifying information indicates the first value.

5. 3. The communication device according to claim 1, wherein the first specific information includes a combination of pieces of information stored in two or more subfields.

6. 3. The communication device according to claim 1, wherein each of the first MCS and the second MCS is determined from within the first MCS group based on definition information that defines a first MCS group consisting of a plurality of different combinations of modulation schemes and coding rates, and a second MCS group that is composed of a plurality of different combinations of modulation schemes and coding rates and is different from the first MCS group.

7. 7. The communication device according to claim 6, wherein the combinations related to the first MCS group have required SNRs closer to each other than the combinations related to the first MCS group and the combinations related to the second MCS group.

8. Each combination related to the first MCS group has the same coding rate, The communication device according to claim 6 , wherein each combination related to the second MCS group has the same coding rate but is different from the coding rate related to the first MCS group.

9. the first specific information includes a combination of information stored in a first sub-field and a second sub-field, The first subfield includes information indicating the first MCS group, 7. The communication device according to claim 6, wherein the second subfield includes information indicating which combination of the plurality of different combinations forming the first MCS group is set to which stream.

10. Implementing multi-user MIMO (Multi Input-Multi Output) communication; The communication device according to claim 9 , wherein the specific SIG includes the first subfield for each of a plurality of the specific communication devices.

11. The communication device according to claim 10 , wherein the specific SIG includes the second subfield that is common to a plurality of the specific communication devices.

12. A communication device having a function of STA (STAtion), A receiving means for receiving a MU (Multi-User) PPDU (Physical Layer Protocol Data Unit) including a U-SIG (Universal Signal field) and a specific SIG following the U-SIG in a preamble; demodulation means for demodulating a data portion of a received MU PPDU based on the specific SIG; The specific SIG includes control information for specifying an MCS (Modulation and Coding Scheme), which is a modulation method and a coding rate of each data portion of a plurality of streams, and includes control information directed to one or more specific STAs including the device itself; the control information includes first identification information; the first identification information indicates that a data portion of a first stream among the plurality of streams is modulated and encoded using a first MCS, and that a data portion of a second stream among the plurality of streams is modulated and encoded using a second MCS; The communication device, wherein the second MCS is different from the first MCS.

13. 3. The communication device according to claim 1, wherein the transmitting means further transmits to the outside a management frame including capability information indicating to the outside whether or not the device supports a function for communicating by applying different modulation methods, or different modulation methods and coding rates, to streams for the same communication partner.

14. A communication device, A communication device characterized by having a communication means for communicating a management frame of the IEEE 802.11 standard, which includes capability information for indicating to an external device whether or not the device supports a function for applying a different modulation method, or a different modulation method and coding rate, to each of the multiple streams when communicating multiple streams to the same communication partner.

15. A control method for controlling communication, comprising: a transmitting step of transmitting a multi-user (MU) physical layer protocol data unit (PPDU) including a universal signal field (U-SIG) and a specific signal field (SIG) following the U-SIG in a preamble; The specific SIG includes control information for specifying a Modulation and Coding Scheme (MCS), which is a modulation method and a coding rate of each data portion of a plurality of streams, and the control information is directed to one or more specific communication devices; The control information may include first identification information, the first identification information indicates that a data portion of a first stream among the plurality of streams is modulated and encoded using a first MCS, and that a data portion of a second stream among the plurality of streams is modulated and encoded using a second MCS; The method of claim 1, wherein the second MCS is different from the first MCS.

16. A program for causing a computer to function as the communication device control method according to claim 15.

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