Wireless communication device and communication method

Abstract

A wireless communication device disclosed herein comprises: a control unit that generates first control information; and a transmission unit that transmits the first control information. The first control information includes at least information (MCS) indicating a modulation scheme and an error correction coding rate, information (NSS) indicating the number of spatial streams, and second control information. The second control information is information indicating whether the modulation schemes applied to each of the spatial streams are all the same. When the second control information indicates that the modulation schemes for each of the spatial streams are not all the same, the first control information includes third control information. The third control information indicates the modulation schemes for each of the spatial streams, and includes information indicating information indicating a reference modulation order in the spatial streams and information indicating the difference with the reference modulation order on the basis of at least the NSS. The reference modulation order is a modulation order of the modulation scheme indicated by the MCS.

Description

Wireless communication device and communication method

[0001] The present application claims priority to Japanese Patent Application No. 2024-132087 filed in Japan on August 8, 2024, and Japanese Patent Application No. 2024-186760 filed in Japan on October 23, 2024, the contents of which are incorporated herein by reference.

[0002] The Institute of Electrical and Electronics Engineers Inc. (IEEE) is continuously working on formulating a new standard for IEEE 802.11, a wireless LAN standard, in order to realize higher efficiency, faster communication speeds, and improved frequency utilization efficiency in wireless LAN (Local Area Network) systems. In recent years, standardization activities have begun for IEEE 802.11bn, the successor to IEEE 802.11be, which aims to achieve Ultra High Reliability (UHR).

[0003] One technology proposed and discussed for specification in the IEEE 802.11bn standardization activities is Unequal Modulation (UEQM), which aims to improve communication performance by applying different modulation methods to different spatial streams in MIMO (Multiple Input Multiple Output) transmission. UEQM was once specified in IEEE 802.11n (HT: High Throughput) established in 2009, but due to factors such as the limited number of spatial streams actually used in MIMO transmission at the time and the fact that beamforming (BF) technology, which gives directionality to transmitted radio waves, was optional, it was not implemented in devices compatible with the IEEE 802.11n standard.

[0004] Comparing the technologies envisaged in the IEEE802.11bn standard with those of the IEEE802.11n standard, for example, the maximum number of spatial streams in MIMO transmission has been expanded from 4 to 8, the maximum modulation level has been expanded from 64QAM to 4096QAM, and beamforming has become more effective. From this perspective, revising UEQM as a specification of the IEEE802.11bn standard is expected to have a greater effect than before in terms of optimizing throughput and improving reliability (Non-Patent Document 1).

[0005] IEEE 802.11-24 / 0016r1

[0006] In order for a wireless communication device to indicate a modulation scheme for each spatial stream, control information is required. The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a wireless communication device and a communication method capable of transmitting control information indicating a modulation scheme for each spatial stream.

[0007] The communication device and communication method according to the present invention for solving the above-mentioned problems are as follows.

[0008] (1) That is, a wireless communication device according to one aspect of the present invention includes a control unit that generates first control information and a transmission unit that transmits the first control information, wherein the first control information includes at least information indicating a modulation scheme and an error correction coding rate (MCS: Modulation and Coding Scheme), information indicating the number of spatial streams (NSS: Number of Spatial Streams), and second control information, wherein the second control information is information indicating whether the modulation schemes applied to the spatial streams are all the same, and when the second control information indicates that the modulation schemes for the spatial streams are not all the same, the first control information includes third control information, wherein the third control information indicates a modulation scheme for the spatial stream and includes, based on at least the NSS, information indicating a reference modulation order in the spatial stream and information indicating a difference from the reference modulation order, and the reference modulation order is the modulation order of the modulation scheme indicated by the MCS.

[0009] (2) Furthermore, a wireless communication device according to one aspect of the present invention is described in (1) above, wherein the third control information has an information amount of 1 bit when the reference modulation order is a certain value, and 2 bits when the reference modulation order is any other value.

[0010] (3) Furthermore, a wireless communication device according to one aspect of the present invention is described in (1) above, wherein the third control information has an information volume of 1 bit if a condition is met and 2 bits otherwise, and the condition includes at least that the NSS is a certain value.

[0011] (4) Furthermore, a wireless communication device according to one aspect of the present invention is described in (3) above, wherein the third control information has an information amount of 1 bit when the NSS is a certain value or when the reference modulation order is a certain value, and has an information amount of 2 bits when the NSS and the reference modulation order are other values.

[0012] (5) Also, a communication method according to one aspect of the present invention includes a step of generating first control information and a step of transmitting the first control information, wherein the first control information includes at least information indicating a modulation scheme and an error correction coding rate (MCS), information indicating the number of spatial streams (NSS), and second control information, and the second control information is information indicating whether the modulation schemes applied to each of the spatial streams are all the same. When the second control information indicates that the modulation schemes for each of the spatial streams are not all the same, the first control information includes third control information, and the third control information indicates a modulation scheme for each of the spatial streams, and includes, based on at least the NSS, information indicating a reference modulation order in the spatial stream and information indicating a difference from the reference modulation order, and the reference modulation order is the modulation order of the modulation scheme indicated by the MCS.

[0013] According to the present invention, in a wireless communication device that supports UEQM, which selects different modulation schemes for different spatial streams, control information related to UEQM can be shared with other wireless communication devices, thereby improving throughput and reliability during data transmission.

[0014] FIG. 1 is a diagram showing an example of a configuration of a wireless communication system according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of a PHY layer frame configuration of a wireless LAN system. FIG. 3 is a diagram showing an example of a MAC layer frame configuration of a wireless LAN system. FIG. 4 is a block diagram showing an example of a configuration of a wireless communication device according to an embodiment of the present invention. FIG. 5 is a table showing an example of a modulation scheme for each spatial stream according to an embodiment of the present invention. FIG. 6 is a diagram showing an example of a configuration of control information according to an embodiment of the present invention. FIG. 7 is a simplified table showing an example of a configuration of an MCS according to an embodiment of the present invention. FIG. 8 is a diagram showing an example of a configuration of control information according to an embodiment of the present invention. FIG. 9 is a table showing an example of a modulation scheme for each spatial stream according to an embodiment of the present invention. FIG. 10 is a diagram showing an example of a configuration of control information according to an embodiment of the present invention. FIG. 11 is a table showing an example of a modulation scheme for each spatial stream according to an embodiment of the present invention. FIG. 12 is a diagram showing an example of a configuration of control information according to an embodiment of the present invention. 10A and 10B are tables showing an example of a modulation scheme for each spatial stream according to an embodiment of the present invention;

[0015] The wireless communication system in this embodiment includes an access point device (also referred to as an AP STA or base station device) and multiple terminal devices (also referred to as non-AP STAs). Furthermore, a wireless communication system and network configured from an access point device and terminal devices connected to the access point device is called a BSS (Basic Service Set, management range). Furthermore, the terminal device according to this embodiment can have the functions of an access point device. Similarly, the access point device according to this embodiment can have the functions of a terminal device. Hereinafter, when simply referred to as an STA or wireless communication device, it refers to both the access point device and the terminal device.

[0016] The access point device and terminal devices within the BSS each perform wireless communication based on CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance). This embodiment focuses on infrastructure mode, in which an access point device performs wireless communication with multiple terminal devices, but the method of this embodiment can also be implemented in ad hoc mode, in which terminal devices perform direct wireless communication with each other. In ad hoc mode, one terminal device acts as an access point device to form a BSS. A BSS in ad hoc mode is also referred to as an IBSS (Independent Basic Service Set). Hereinafter, a terminal device that forms an IBSS in ad hoc mode can also be considered an access point device.

[0017] FIG. 1 is a diagram showing an example of a wireless communication system according to this embodiment. FIG. 1 shows an example of an environment in which a wireless communication system 100-1 (also referred to as BSS 100-1) consisting of an access point (AP) device 101-1, a terminal device 102-1, and a legacy terminal device 103-1, and a wireless communication system 100-2 (also referred to as BSS 100-2) consisting of an access point (AP) device 101-2, a terminal device 102-2, and a legacy terminal device 103-2 exist in such a manner that their communication areas partially or completely overlap. In this embodiment, a case will be described as an example in which wireless frames transmitted by each wireless communication device are received by all other wireless communication devices (can be observed at a predetermined reception power or higher). Such other BSSs with overlapping communication areas are called OBSSs (Overlapping BSSs). In the example of the wireless communication system shown in FIG. 1, BSS 100-1 and BSS 100-2 recognize each other's BSS as an OBSS. In this embodiment, the term "legacy terminal device" refers to a conventional terminal device to which the present invention is not applied, such as a terminal device conforming to the IEEE 802.11ax standard. Similarly, the term "legacy access point device" refers to a conventional access point device to which the present invention is not applied, such as an access point device conforming to the IEEE 802.11ax standard. Furthermore, the legacy access point device and the legacy terminal device are collectively referred to as "legacy wireless communication devices." Although the wireless communication system 100-1 and the wireless communication system 100-2 form different BSSs, this does not necessarily mean that the ESSs (Extended Service Sets) representing the service sets forming the LANs are different. In other words, wireless communication devices belonging to the same ESS can be considered to belong to the same network from a higher layer. Furthermore, BSSs can be coupled via a DS (Distribution System) to form an ESS. Each of the wireless communication systems 100-1 and 100-2 can further include multiple terminal devices, legacy terminal devices, or both.

[0018] In an IEEE 802.11 wireless communication system, each wireless communication device can transmit multiple types of frames with a common frame format, which are defined at the physical (PHY) layer, medium access control (MAC) layer, and logical link control (LLC) layer.

[0019] A PHY layer frame is called a physical protocol data unit (PPDU, PHY protocol data unit, physical layer frame). Hereinafter, a PHY layer frame is also referred to as a radio frame. Unless otherwise specified, the term "frame" refers to a radio frame. A PPDU includes a training field (TF) used for signal detection, propagation path estimation, and assisting demodulation processing in the physical layer, a signal field (SIG) containing information for signal processing in the physical layer, and a physical service data unit (PSDU, PHY service data unit), which is a data unit processed in the physical layer. A PSDU can also include an aggregated MPDU (A-MPDU, Aggregated MPDU), which aggregates multiple MAC protocol data units (MPDU, MAC layer frames), which serve as retransmission units in the wireless section.

[0020]

[0003] Figure 2 shows an example of a PHY layer frame and PPDU configuration in a wireless LAN system. Figure 2 shows an example of a PPDU configuration in each of the standards IEEE 802.11n (also referred to as HT: High Throughput), IEEE 802.11ac (also referred to as VHT: Very High Throughput), IEEE 802.11ax (also referred to as HE: High Efficiency), and IEEE 802.11be (also referred to as EHT: Extremely High Throughput). The PPDU includes multiple short training fields (STF: Short Training Fields) used for signal detection and synchronization, and multiple long training fields (LTF: Long Training Fields) used to acquire channel information for data demodulation. STF is classified into L-STF (non-HT Short Training Field), HT-STF (High Throughput Short Training Field), VHT-STF (Very High Throughput Short Training Field), HE-STF (High Efficiency Short Training Field), EHT-STF (Extremely High Throughput Short Training Field), etc. depending on the corresponding standard. LTF is also classified into L-LTF, HT-LTF, VHT-LTF, HE-LTF, EHT-LTF, etc. depending on the corresponding standard. In addition, PPDUs that comply with standards earlier than IEEE 802.11n are also referred to as non-HT PPDUs.

[0021] Similarly, the SIGNAL field included in the PPDU is classified into L-SIG, HT-SIG, VHT-SIG, HE-SIG, EHT-SIG, etc. according to the corresponding standard. VHT-SIG is further classified into VHT-SIG-A1, VHT-SIG-A2, and VHT-SIG-B. Similarly, HE-SIG is classified into HE-SIG-A1 to HE-SIG-A4 and HE-SIG-B. As shown in FIG. 2 , the L-SIG field includes multiple subfields such as RATE and LENGTH. The LENGTH subfield of the L-SIG field indicates information about the length of the PPDU, such as the number of octets or the time length. Additionally, a U-SIG (Universal SIG) field containing additional control information may be included in anticipation of specification updates within the same standard. The RL-SIG field included in the PPDUs (HE PPDU and EHT PPDU) of the IEEE 802.11ax and IEEE 802.11 11be standards is a repetition of the L-SIG field, and can be used to distinguish the HE PPDU and EHT PPDU from PPDUs of earlier standards.

[0022] Furthermore, the PPDU may include information identifying the BSS that is the source of the frame (hereinafter also referred to as BSS identification information). The information identifying the BSS may be, for example, the SSID (Service Set IDentifier) ​​of the BSS or the MAC address of the access point device of the BSS. The information identifying the BSS may also be a value unique to the BSS (for example, a BSS Color) other than the SSID or MAC address. Information indicating the BSS Color may be included in the HE-SIG-A or U-SIG.

[0023] A PPDU in accordance with the IEEE 802.11ax standard and the IEEE 802.11be standard may include a PE field (Packet Extension field) added thereto to ensure the time required for receiving and processing the PPDU.

[0024] 3 shows an example of the structure of an MPDU, which is a MAC layer frame in a wireless LAN system. The MPDU is composed of a MAC header containing information for signal processing in the MAC layer, a MAC Service Data Unit (MSDU) or frame body, which is a data unit input to and processed in the MAC layer, and a Frame Check Sequence (FCS) field, which checks whether the MAC layer frame is error-free. Multiple MSDUs can also be aggregated as an aggregated MSDU (A-MSDU) and included in the frame body.

[0025] Each wireless communication device can recognize the frame type and subframe type of a received MAC layer frame by reading the contents of the frame control field included in the MAC header. MAC layer frame types are broadly classified into three types: management frames that manage the connection status between wireless communication devices, control frames that manage the communication status between wireless communication devices, and data frames that contain actual transmission data. Each type is further classified into multiple subframe types. Control frames include acknowledgement (Ack or ACK) frames, block acknowledgement (BA or BlockAck) frames, request to send (RTS) frames, and clear to send (CTS) frames. BA can acknowledge (notify completion of reception) multiple MPDUs. Management frames include beacon frames, probe request frames, probe response frames, authentication frames, association request frames, and association response frames. The data frames include a data frame, a polling (CF-Poll) frame, and the like.

[0026] The MAC header also includes a Duration / ID field. In some frame types, the Duration / ID field indicates the association identification number (AID: Association IDentifier) ​​of the frame sender, and in other frame types, it can indicate the duration of occupation of the wireless medium by the transmission of the frame, or the duration of occupation of the wireless medium by the transmission of the frame and the exchange of a series of frames associated with it. Note that the Duration / ID field is also simply referred to as the Duration field when it indicates the duration.

[0027] The MAC header can also include up to four address fields indicating MAC addresses, and the address fields at positions determined according to the frame type, etc. display the BSS identifier (BSSID), source address (SA), destination address (DA), transmitting address (TA), receiving address (RA), etc. Hereinafter, the various address information indicated in the address fields of the MAC header will be collectively referred to as address information or MAC address information.

[0028] A beacon frame includes fields indicating the period at which beacons are transmitted (beacon interval) and the SSID, which is a string used to identify the BSS. An access point device can periodically broadcast a beacon frame within a BSS, and a terminal device can recognize surrounding access point devices by receiving the beacon frame. The process by which a terminal device recognizes an access point device based on a beacon frame broadcast by an access point device is called passive scanning. On the other hand, the process by which a terminal device searches for an access point device by broadcasting a probe request frame within a BSS is called active scanning. The access point device can transmit a probe response frame in response to the probe request frame, and the content of the probe response frame is the same as the content of the beacon frame.

[0029] After recognizing an access point device, a terminal device performs a connection process with the access point device. The connection process is classified into an authentication procedure and an association procedure. The terminal device transmits an authentication request frame to the access point device to which it wishes to connect. Upon receiving the authentication request frame, the access point device transmits an authentication response frame to the terminal device, the authentication response frame including a status code indicating whether the terminal device has been authenticated. The terminal device can determine whether its authentication request has been approved by the access point device by reading the status code included in the authentication response frame. The access point device and terminal device can exchange authentication request frames and authentication response frames (both of which are collectively referred to as authentication frames) multiple times.

[0030] Following the authentication procedure, the terminal device transmits a connection request frame to the access point device to perform a connection procedure. Upon receiving the connection request frame, the access point device determines whether to permit the terminal device to connect and transmits a connection response frame to notify the determination. The connection response frame includes an AID for identifying the terminal device in addition to a status code indicating whether the connection process is successful. The access point device can manage multiple terminal devices by assigning different AIDs to each terminal device for which it has issued connection permission.

[0031] After the connection process is completed, the access point device and the terminal device perform actual data transmission. In the IEEE 802.11 system, the Distributed Coordination Function (DCF), the Point Coordination Function (PCF), and the Hybrid Coordination Function (HCF), which is an extension of these, are defined as media access methods. Specific implementation methods of the HCF include Enhanced Distributed Channel Access (EDCA) and HCF Controlled Channel Access (HCCA).

[0032] An example of the operation when a wireless communication device transmits a wireless frame based on DCF will be described. In DCF, a wireless communication device performs carrier sense (CS) to check the usage status of wireless channels surrounding the wireless communication device prior to communication. For example, if a wireless communication device that is about to transmit a frame receives a signal with a received power higher than a predetermined clear channel assessment level (CCA level) on the wireless channel during the carrier sense period performed prior to transmission, the wireless communication device postpones the transmission of the frame on the wireless channel. Hereinafter, a state in which a signal with a received power equal to or higher than the CCA level is detected on the wireless channel is referred to as a busy state of the wireless medium, and a state in which a signal with a received power equal to or higher than the CCA level is not detected is referred to as an idle state of the wireless medium. Thus, carrier sense performed by each wireless communication device based on the power level of a signal actually received is referred to as physical carrier sense (physical CS). The CCA level is also referred to as a carrier sense level (CS level) or a CCA threshold (CCAT). Furthermore, when the wireless communication device detects a signal with reception power equal to or higher than the CCA level, it starts an operation to demodulate the signal at least in the PHY layer.

[0033] A wireless communication device performs carrier sensing during an interframe space (IFS) period set according to the frame type and subframe type to be transmitted, and determines whether the wireless channel is in a busy or idle state. The IEEE 802.11 system defines multiple IFSs with different periods, including a short interframe space (SIFS) used for frames assigned the highest priority, a polling interframe space (PIFS: PCF IFS) used for frames with relatively high priority, and a distributed arbitration interframe space (DIFS: DCF IFS) used for frames with low priority. When transmitting data frames using DCF, the wireless communication device uses the DIFS.

[0034] After waiting for the DIFS period, the wireless communication device further waits for a random backoff time to prevent frame collisions. In the IEEE 802.11 system, a random backoff time based on a contention window (CW) is used. CSMA / CA assumes that a frame transmitted by a transmitting station is received by a receiving station without interference from other transmitting stations. Therefore, if multiple transmitting stations transmit frames at the same time, the frames may collide with each other, potentially preventing the receiving station from receiving the frames correctly. Therefore, frame collisions are avoided by having each transmitting station wait for a randomly set time before starting transmission. When the wireless communication device determines that the wireless channel is idle through carrier sense, it starts counting down a backoff counter set based on the CW. Only when the backoff counter reaches 0 does it acquire a transmission opportunity (TXOP) and become able to transmit a frame. The wireless communication device continues carrier sense even during the backoff counter countdown, and stops counting down the backoff counter if it determines that the wireless channel is busy again. When the wireless channel becomes idle again, the wireless communication device waits for the same period as the previous IFS, and then resumes counting down the remaining portion of the backoff counter. The TXOP acquisition procedure using the backoff counter is also called a backoff procedure.

[0035] The wireless communication device, which is the receiving station, receives the frame, reads information such as the SIGNAL field according to the standard of the frame, and demodulates the received frame.The wireless communication device can then identify whether the frame is addressed to the wireless communication device by reading the MAC header of the demodulated signal.The wireless communication device can also determine the destination of the frame based on information contained in the SIGNAL field, such as a group identification number (GID: Group ID) contained in VHT-SIG-A.

[0036] If a wireless communication device determines that a received frame is addressed to the device itself and demodulates the frame without error, it must transmit an Ack frame to the wireless communication device (transmitting station) indicating that the frame was received correctly. The Ack frame is one of the highest-priority frames that is transmitted by simply waiting for the SIFS period (without a random backoff time). The wireless communication device (transmitting station) terminates a series of communications upon receiving the Ack frame transmitted from the wireless communication device (receiving station). Note that if the wireless communication device (receiving station) fails to receive the frame correctly, the wireless communication device (receiving station) does not transmit the Ack frame. Therefore, if the wireless communication device (transmitting station) does not receive an Ack frame from the receiving station within a certain period (SIFS + Ack frame length) after transmitting the frame, it determines that the communication has failed and terminates the communication. In this way, the end of one communication (also called a burst) in an IEEE 802.11 system is always determined by whether or not an Ack frame is received, except in special cases such as when transmitting a beacon frame or other notification signal, or when fragmentation is used to divide the transmitted data.

[0037] Next, an example of the operation when an access point device transmits a signal to a terminal device based on PCF will be described. Unlike DCF, in which each device performs carrier sensing and autonomously acquires the transmission right, in PCF, a control station called a point coordinator controls the transmission right of each device within the BSS. Generally, the access point device becomes the point coordinator and acquires the transmission right for the terminal device within the BSS.

[0038] The communication period by PCF includes a contention-free period (CFP) and a contention period (CP). During the CP, communication is performed based on the DCF described above, and the point coordinator controls the transmission right during the CFP. The access point device, which is the point coordinator, broadcasts a beacon frame including information such as the maximum duration of the CFP (CFP Max duration) within the BSS prior to PCF communication. Note that the beacon frame broadcast at the start of PCF transmission uses PIFS and is transmitted without going through a backoff procedure. A terminal device that receives the beacon frame sets the value of the CFP Max duration included in the beacon frame in a network allocation vector (NAV), which holds the period during which no frame transmission is performed to the wireless medium. After that, until the duration set in the NAV elapses or a signal announcing the end of the CFP within the BSS (for example, a data frame including CF-End) is received, the terminal device can acquire the transmission right only when it receives a signal from the point coordinator signaling acquisition of the transmission right for itself (for example, a data frame including CF-Poll). Note that, since packet collisions do not occur within the same BSS during the CFP period, each terminal device does not take the random backoff time used in DCF.

[0039] Furthermore, we will also explain TXOP in EDCA, a data transmission method different from DCF. The IEEE 802.11e standard is related to EDCA and specifies TXOP from the perspective of quality of service (QoS) guarantee for various services such as video transmission and VoIP (Voice over IP). Services are broadly classified into four access categories: VO (Voice), VI (Video), BE (Best Effort), and BK (Background). Generally, the order of priority is VO, VI, BE, and BK. Each access category has parameters such as the minimum CW value (CWmin), the maximum CW value (CWmax), AIFS (Arbitration IFS), which is a type of IFS, and TXOP limit, which is the upper limit of transmission opportunities, and these parameters are set to differentiate between high and low priorities. For example, by setting the CWmin, CWmax, and AIFS of VO, which has the highest priority for voice transmission, to relatively small values ​​compared to other access categories, data transmission can be prioritized over other access categories. For example, in VI, which transmits a relatively large amount of data for video transmission, setting the TXOP limit to a large value makes it possible to secure longer transmission opportunities than in other access categories. In this way, the values ​​of the four parameters of each access category are adjusted to guarantee QoS according to various services.

[0040] In addition, TIDs (Traffic IDentifiers) can be used to set QoS for MSDUs input from higher layers to the MAC layer, and eight of the TIDs can identify traffic categories (TCs), while the remaining eight can identify parameterized traffic streams (TSs).

[0041] Fig. 4 is a diagram showing an example of the configuration of a wireless communication device 400 according to this embodiment. The example configuration of the wireless communication device 400 shown in Fig. 4 is a configuration common to the access point devices 101-1 and 101-2 and the terminal devices 102-1 and 102-2 in Fig. 1. Note that the basic block configuration of the legacy terminal devices 103-1 and 103-2 in Fig. 1 is the same as that of the wireless communication device 400, but the operation of some blocks differs.

[0042] The wireless communication device 400 is composed of an upper layer section (upper layer step) 401, a communication control section (communication control step) 402, a wireless transmission section (wireless transmission step) 403, a wireless reception section (wireless reception step) 404, a carrier sense section (carrier sense step) 405, and an antenna section 406.

[0043] The upper layer unit 401 may be implemented with some or all of the functions of the layers above the MAC layer and may perform processing. Note that the functions of the upper layer unit 401 are not limited to this, and may further include, for example, some functions of the MAC layer.

[0044] The communication control unit 402 generates MPDUs for control frames and management frames, outputs them to the wireless transmission unit 403, and instructs transmission. The communication control unit 402 also uses the data unit (MSDU) input from the upper layer unit 401 as a frame body, and adds a MAC header including fields such as the BSSID of the BSS to which the wireless communication device 400 belongs, the source address, the destination address, the sending address, and the receiving address, QoS control information related to the MSDU, and a duration, as well as an FCS (Frame Check Sequence) for error detection, to generate an MPDU for the data frame, and outputs it to the wireless transmission unit 403 to instruct transmission. The duration can be set to the duration of wireless medium occupation by the transmission of the frame, the duration of wireless medium occupation by the transmission of the frame and the exchange of a series of frames associated therewith, or the duration of the TXOP to be secured. The communication control unit 402 may also output an A-MPDU, which aggregates multiple MPDUs, to the wireless transmission unit 403.

[0045] The instruction to transmit a frame to the wireless transmitting unit 403 may be executed when the carrier sense result by the carrier sense unit 405 is in the idle state and after a TXOP is acquired based on the backoff procedure. Note that the above carrier sense and backoff procedures can be omitted for frames that can be transmitted without carrier sense, such as an Ack frame for a received frame or a response frame for a frame addressed to the device itself from the TXOP holder.

[0046] Furthermore, the communication control unit 402 performs processing on the received MPDU input from the wireless receiving unit 404. The communication control unit 402 performs a cyclic redundancy check (CRC) on the received MPDU and compares it with the value of the FCS field to confirm whether the MPDU contains any errors. If the communication control unit 402 confirms that the MPDU contains no errors, it extracts the MAC header of the MPDU and identifies the frame type and subframe type from the frame control field. Based on the identified frame type and subframe type, the communication control unit 402 extracts the remaining fields of the MAC header and obtains information such as duration information, address information, and QoS control information indicated in each field. Note that an A-MPDU may also be input from the wireless receiving unit 404. In this case, the wireless control unit 402 separates the A-MPDU into individual MPDUs and performs the above-described reception processing.

[0047] The communication control unit 402 identifies, from the acquired address information, whether the received MPDU is addressed to the device itself (including multicast and broadcast frames including the device itself), and whether it is a frame within the BSS to which the device itself belongs (referred to as an intra-BSS frame) or a frame of another BSS (referred to as an inter-BSS frame). The communication control unit 402 inputs the address information, the identification result of whether the frame is an intra-BSS frame, and duration information to the carrier sense unit 405. Furthermore, if the communication control unit 402 identifies the received MPDU as addressed to the device itself and the MPDU contains a frame body, i.e., an MSDU, it outputs the MSDU to the upper layer unit 401. The communication control unit 402 may output information such as the acquired address information and QoS control information together with the MSDU to the upper layer unit 401.

[0048] The wireless transmitting unit 403 generates a PPDU by treating the MPDU or A-MPDU input from the communication control unit 402 as a PSDU and adding a training field and a SIGNAL field to the PSDU. For example, in the case of a PPDU conforming to the IEEE 802.11be standard, the wireless transmitting unit 403 generates a PPDU by adding L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-SIG, EHT-STF, and EHT-LTF before the PSDU. Furthermore, the wireless transmitting unit 403 may add a PE field to the end of the PPDU as necessary.

[0049] The wireless transmitting unit 403 performs processes such as error correction coding, digital modulation, mapping, frequency-time conversion, digital-to-analog conversion, filtering, and up-conversion to radio frequency (RF) on the generated PPDU to generate a wireless signal, which is then transmitted from the antenna unit 406 at the transmission timing instructed by the communication control unit 402.

[0050] The wireless receiver 404 down-converts the wireless signal received by the antenna 406 and performs processing such as filtering and analog-to-digital conversion to obtain a digital received signal. If the wireless receiver 404 detects L-STF and L-LTF from the received signal and successfully synchronizes with the received frame, it can further perform time-frequency conversion, demapping, digital demodulation, error correction decoding, etc. on the obtained digital received signal to obtain a received PPDU. The wireless receiver 404 outputs the obtained PPDU to the communication control unit 402. Note that if the wireless receiver 404 fails to obtain the L-SIG field, i.e., if the parity check of the L-SIG field is not successful, it may abort the acquisition of the frame. Furthermore, if a BSS-specific value such as BSS Color is obtained from the HE-SIG-A or U-SIG, and the BSS-specific value differs from that of the BSS to which the wireless receiver 404 belongs, the wireless receiver 404 may abort the acquisition of the frame.

[0051] The wireless receiving unit 404 monitors the received signal from the antenna unit 406, and if it does not detect a signal with a received power equal to or greater than a predetermined CCA level (hereinafter also referred to as the CCA-ED level) for energy detection (ED), it sets a CCA indication (also referred to as a PHY-CCA indication), which indicates whether the wireless medium is available, to an idle state and outputs it to the carrier sense unit 405.If it detects a signal with a received power equal to or greater than the CCA-ED level, it sets the CCA indication to a busy state and notifies the carrier sense unit 405.

[0052] When the wireless receiving unit 404 detects L-STF and L-LTF from the received signal at a reception power equal to or greater than a predetermined CCA level for signal detection (SD) (hereinafter also referred to as the CCA-SD level), the wireless receiving unit 404 sets the CCA indication to a busy state and notifies the carrier sense unit 405. This reception power detection is also called preamble detection. Furthermore, when the wireless receiving unit 404 successfully acquires the L-SIG field, the wireless receiving unit 404 maintains the CCA indication in a busy state for a period based on the LENGTH subfield in the L-SIG field. Note that the wireless receiving unit 404 may set the CCA-ED level higher than the CCA-SD level, for example, the CCA-SD level may be set to -82 dBm and the CCA-ED level may be set to -62 dBm. Furthermore, if a value specific to a BSS, such as BSS Color, is acquired from HE-SIG-A or U-SIG and the value differs from that of the BSS to which the device belongs, wireless receiving unit 404 may change the CCA-SD level to a higher value. At this time, wireless transmitting unit 403 preferably reduces the transmission power in conjunction with raising the CCA-SD level.

[0053] The carrier sense unit 405 receives a CCA indication from the wireless receiving unit 404, and receives an identification result indicating whether the received MPDU is addressed to the device itself and whether it is an intra-BSS frame or an inter-BSS frame, as well as duration information, from the communication control unit 402. Carrier sense based on this CCA indication is called physical carrier sense (physical CS).

[0054] The carrier sense unit 405 has an indicator called a Network Allocation Vector (NAV), which maintains time periods during which the device does not transmit frames to the wireless medium, regardless of the state of the physical CS. The NAV can be expressed as a countdown timer and is also referred to as a NAV timer or NAV counter. Hereinafter, the NAV will be described as being expressed as a countdown timer, but this is not limited to this. The carrier sense unit 405 of the terminal device has two types of NAV: a basic NAV and an intra-BSS NAV. Furthermore, the carrier sense unit 405 of the access point device can have two types of NAV: a basic NAV and an intra-BSS NAV. Details of updating the NAV value will be described later.

[0055] The carrier sense unit 405 determines that the virtual carrier sense (virtual CS) is in an idle state if both the basic NAV and the intra-BSS NAV are 0, and determines that the virtual CS is in a busy state if at least one NAV is non-zero.

[0056] The carrier sense unit 405 outputs to the communication control unit 402 that the carrier sense result is in an idle state when both the physical CS and the virtual CS are in an idle state, and outputs that the carrier sense result is in a busy state when either the physical CS or the virtual CS is in a busy state.

[0057] This embodiment is described below as being performed in a BSS consisting of two communication devices, wireless communication device 1 and wireless communication device 2, which have the same configuration as wireless communication device 400 in Fig. 4. However, the number of wireless communication devices in the BSS may be three or more. The BSS also includes wireless communication devices (also referred to as UHR STAs) that comply with the IEEE802.11bn standard or the next-generation standard of IEEE802.11bn, and in this embodiment, at least wireless communication device 1 and wireless communication device 2 are included. Note that the numbers are used for convenience, and the series of operations of wireless communication device 1 and wireless communication device 2 are interchangeable in this embodiment.

[0058] Each of the wireless communication devices 1 and 2 has multiple antennas and is capable of spatially multiplexing multiple channels using MIMO (Multiple-Input Multiple-Output) transmission. Each spatially multiplexed channel is also referred to as a spatial stream. The wireless communication device in this embodiment may transmit data using beamforming (BF). For example, beamforming involves a transmitter performing spatial filtering based on a beamforming steering matrix obtained from the MIMO propagation path (or channel estimate). Beamforming is expected to improve the received signal power or signal-to-noise ratio (SNR) at the receiver and improve the spatial separation performance of MIMO. With beamforming, each spatial stream has an SNR corresponding to the propagation path. For example, a spatial stream with a larger SNR can be prioritized for data transmission. Hereinafter, spatial streams with larger SNRs (or larger eigenvalues) are referred to as the first stream, second stream, and so on, in descending order.

[0059] During data transmission, a technique that applies different modulation methods to spatial streams under a common error correction coding rate is called Unequal Modulation (UEQM). In this embodiment, UEQM uses the modulation order (modulation method) of a certain spatial stream as a reference and indicates the modulation order of each spatial stream as the difference from that modulation order. For example, the modulation orders, in ascending order, are BPSK (Binary Phase Shift Keying), QPSK (Quadrature PSK), 16QAM (Quadrature Amplitude Modulation), 64QAM, 256QAM, 1024QAM, and 4096QAM. In the following examples, the reference modulation order will be described as M, and modulation orders different from the reference modulation order will be indicated as differences from M, such as M-1, M-2, and M+1. For example, if M is 256QAM, M-1 is 64QAM, M-2 is QPSK, and M+1 is 1024QAM. Furthermore, in the following embodiments, unless otherwise specified, the modulation method applied to the first stream will be described as M, but the present invention is not limited to this, and streams other than the first stream can also be M.

[0060] In UEQM, the combination of modulation orders for each spatial stream depends on the number of spatial streams (NSS). Therefore, the NSS to which UEQM is applied and the difference in modulation orders for each spatial stream when UEQM is applied may be limited (restricted). For example, FIG. 5 is a table showing combinations of modulation orders for each spatial stream when UEQM is applied with a maximum NSS of 4 and a maximum difference in modulation orders for each spatial stream limited to 2. In the example of FIG. 5, UEQM is applicable when NSS is 2 or greater. When NSS is 2, the modulation orders for each spatial stream are given in the order of M and M-1, or M and M-2, starting from the first stream. When NSS is 3, the modulation orders for each spatial stream are given in the combination of M, M, and M-1, M, M, and M-2, or M, M-1, and M-2. When NSS is 4, the modulation orders for each spatial stream are given as a combination of M, M, M and M-1, or M, M, M and M-2, or M, M, M-1 and M-2. However, the maximum number of spatial streams, the maximum value of the difference in modulation orders for each spatial stream, and the combination of modulation orders do not need to be limited to those shown above. Hereinafter, in the text and figures, when NSS is 2, the modulation order of the first stream is given as M １ , the modulation order of the second stream is M ２ This means that the modulation order for each spatial stream is M １ / M ２ Similarly, when NSS is 3, the modulation order is M １ , M ２ and M ３ It means that M １ / M ２ / M ３ When NSS is 4, the modulation order is M １ , M ２ , M ３ and M ４ It means that M １ / M ２ / M ３ / M ４ It is sometimes written as "is."

[0061] Wireless communication device 1 and wireless communication device 2 transmit first control information to each other. The first control information may be a first configuration including at least information indicating the NSS, or may be a second configuration including at least information indicating the NSS and information related to the UEQM. The information indicating the NSS is also referred to as second control information. The information related to the UEQM is also referred to as third control information. In the following embodiments, the first control information is also referred to as the User field or ULA Control subfield of the UHR-SIG. In the following embodiments, the third control information is also referred to as the UHR-MCS, UEQM Gap information (not included in the UEQM Control information), UEQM Control information, or UEQM Code information.

[0062] When wireless communication device 1 performs connection processing with wireless communication device 2, it transmits a connection request frame. When wireless communication device 2 receives the connection request frame, it determines whether to permit connection with wireless communication device 1 and transmits a connection response frame to notify the determination. The connection request frame and connection response frame include a field indicating capability information of the sender wireless communication device. Specifically, the connection request frame and connection response frame transmitted by a UHR STA include a UHR Capabilities element, which may include some or all of a UHR MAC Capabilities Information field, a UHR PHY Capabilities Information field, and a Supported UHR-MCS And NSS Set field.

[0063] Information indicating Tx Unequal Modulation Supported information, Rx Unequal Modulation Supported information, or both, included in one of the fields in the connection response frame is also referred to as UEQM Supported information. Based on the value of the subfield indicating UEQM Supported information, the wireless communication device 1 can determine whether UEQM is applicable as a modulation method for data transmission to the wireless communication device 2. In the present embodiment, as an example, when the value of the subfield indicating UEQM Supported information is 1, UEQM is applicable for both transmission and reception. The value of the subfield indicating UEQM Supported information can also indicate whether transmission is possible using UEQM and whether reception is possible using UEQM. Similarly, the wireless communication device 2 can determine whether UEQM is applicable to the wireless communication device 1 based on the UEQM Supported information included in the connection request frame transmitted by the wireless communication device 1. Similar capability information is also included in beacon frames, probe request frames, probe response frames, and the like, and the wireless communication devices may acquire each other's UEQM Supported information through these transmissions and receptions.

[0064] When the values ​​of the subfields indicating UEQM Supported information of both the wireless communication device 1 and the wireless communication device 2 are 1, the UHR-SIG, which is a control signal in the PHY header generated and transmitted by the wireless communication device 1, includes control information related to the UEQM. An example of transmission and reception of the UHR-SIG when the UEQM is applicable will be described. The UHR-SIG consists of a Common field that is independent of (or common to) the destination wireless communication device and a User Specific field that is individually set for each user. The User Specific field includes a User field, which includes control information required for each user depending on the transmission method. For example, in non-MU-MIMO single-user transmission, the User field can include an NSS and / or a UHR Modulation and Coding Scheme (UHR-MCS). For example, as shown in FIG. 6, the User field specifically includes some or all of the elements indicating control information such as STA-ID, UHR-MCS, NSS, Beamformed, and Coding. Here, STA-ID is identification information specifying the destination station device, Beamformed is information indicating whether beamforming is implemented, and Coding is information indicating the coding method. UHR-MCS is control information indicating the modulation scheme for each spatial stream and the error correction coding rate common to the spatial streams, and the range of possible values ​​can be changed based on the NSS. The UHR-MCS shown in the table in Figure 7 is an example when the NSS is 4 and the maximum difference between the modulation orders of each spatial stream is 2, and is shown as an index indicating the combination of UEQM application based on the NSS. Specifically, when the UHR-MCS value is 0 to 15 (referred to as range A), the modulation order for each spatial stream is common; when the UHR-MCS value is 16 to 29 (referred to as range B), the modulation order for each spatial stream is M / M / M / M-1; when the UHR-MCS value is 30 to 43 (referred to as range C), the modulation order is M / M / M / M-2; and when the UHR-MCS value is 44 or higher (referred to as range D), the modulation scheme and coding rate indicated by the UHR-MCS are given in order of increasing data rate, with the index value increasing within range A, range B, range C, and range D. Range A is also referred to as the first range.Furthermore, the range of index values ​​indicated by the UHR-MCS, consisting of ranges A, B, C, and D, is also referred to as the second range. When NSS is 1, the UHR-MCS can take on values ​​in the first range. When NSS is 2 or greater, the UHR-MCS can take on values ​​in the second range. The wireless communication device 2 that receives the UHR-SIG can interpret the UHR-MCS based on the relationship shown in FIG. 7, for example, to perform demodulation corresponding to the modulation scheme for each spatial stream. However, the above-mentioned UHR-MCS value ranges, the indexes corresponding to the above-mentioned ranges, the combinations of modulation orders, and the coding rates do not all need to be limited to the format shown in FIG. 7.

[0065] Also, in non-MU-MIMO single-user transmission, an example will be described in which the User field in the UHR-SIG includes at least the NSS, information indicating the modulation scheme and error correction coding rate (MCS: Modulation and Coding Scheme), and UEQM Gap information. As shown in Figure 8, the User field specifically includes some or all of the elements indicating control information such as STA-ID, MCS, NSS, UEQM Gap, Beamformed, and Coding. The UEQM Gap information is control information that indicates the modulation scheme indicated by the MCS as the reference modulation order M and the modulation scheme for each spatial stream based on the NSS as the difference from the reference modulation order. An example is shown in the table of Figure 9. Specifically, when NSS is 4, if the value of the UEQM Gap information is 00, the modulation order of each spatial stream is the same (M / M / M / M), if the value of the UEQM Gap information is 01, the modulation order for each spatial stream is M / M / M / M-1, if the value of the UEQM Gap information is 10, it is M / M / M / M-2, and if the value of the UEQM Gap information is 11, it is M / M / M-1 / M-2. A wireless communication device 2 that receives a UHR-SIG including the UEQM Gap information of this example can perform demodulation corresponding to the modulation method for each spatial stream by interpreting the UEQM Gap information based on the relationship shown in Figure 9. However, the correspondence between the UEQM Gap information and the modulation order does not need to be limited to the format shown in Figure 9.

[0066] Also, an example will be described in which the User field in the UHR-SIG in non-MU-MIMO single user transmission includes at least the NSS and MCS, and further includes variable length control information related to the UEQM depending on the conditions.

[0067] For example, the User field in the UHR-SIG includes at least NSS, MCS, and UEQM Control information. That is, as shown in FIG. 10 , the User field specifically includes some or all of the elements indicating control information, such as STA-ID, MCS, NSS, UEQM Control, Beamformed, and Coding. The UEQM Control information is composed of EQM / UEQM information (also referred to as fourth control information) or EQM / UEQM information and UEQM Gap information. When UEQM Gap information is included in UEQM Control information, the UEQM Gap information is also referred to as fifth control information. When the wireless communication device 1 applies a common modulation scheme to all spatial streams, the value of the EQM / UEQM information is set to 0, and the UEQM Gap information is not included in the UEQM Control information. On the other hand, when the wireless communication device 1 applies UEQM, the value of the EQM / UEQM information is set to 1, and the UEQM Gap information is included in the UEQM Control information. The UEQM Gap information can indicate the modulation scheme for each spatial stream as a difference from a reference modulation order, for example, as shown in the table of FIG. 11 . Specifically, when NSS is 4, if the value of the UEQM Gap information is 00, the modulation order for each spatial stream is the same; if the value of the UEQM Gap information is 01, the modulation order for each spatial stream is M / M / M / M-1; if the value of the UEQM Gap information is 10, the modulation order for each spatial stream is M / M / M / M-2; or if the value of the UEQM Gap information is 11, the modulation order for each spatial stream is M / M / M-1 / M-2. The wireless communication device 2 that receives a UHR-SIG containing the UEQM Control information of this example references the value of the EQM / UEQM information and, if UEQM Gap information is present, interprets it based on the relationship shown in FIG. 11 , thereby enabling demodulation corresponding to the modulation scheme for each spatial stream. However, the correspondence between the UEQM Gap information and the modulation order does not need to be limited to the format shown in FIG. 11 .

[0068] In another example, the User field in the UHR-SIG includes at least an NSS and an MCS, and can include UEQM Control information when the NSS value is 2 or greater and the maximum modulation order indicated by the MCS is QPSK or greater (FIG. 10). The UEQM Control information is composed of EQM / UEQM information, or EQM / UEQM information and UEQM Gap information. When the wireless communication device 1 applies a common modulation scheme to all spatial streams, the value of the EQM / UEQM information is set to 0, and UEQM Gap information is not included in the UEQM Control information. On the other hand, when the wireless communication device 1 applies UEQM, the value of the EQM / UEQM is set to 1, and UEQM Gap information is included in the UEQM Control information. The UEQM Gap information can indicate the modulation scheme for each spatial stream as a difference from a reference modulation order, as shown in the table of FIG. 11, for example. Specific combinations are similar to those in the above example. The wireless communication device 2 that receives the UHR-SIG including the UEQM Control information of this example can perform demodulation corresponding to the modulation method for each spatial stream by referring to the EQM / UEQM information, if present, based on the values ​​of NSS and MCS, and further interpreting the UEQM Gap information, if present, based on the relationship shown in Fig. 11. However, the correspondence between the UEQM Gap information and the modulation order does not need to be limited to the format shown in Fig. 11.

[0069] In another example, the User field in the UHR-SIG includes at least an NSS and an MCS. When the NSS value is 2 or greater and the maximum modulation order indicated by the MCS is QPSK or greater, the UEQM Control information can include variable-length UEQM Control information ( FIG. 10 ). The UEQM Control information is composed of EQM / UEQM information, or EQM / UEQM information and UEQM Gap information. When the wireless communication device 1 applies a common modulation scheme to all spatial streams, the value of the EQM / UEQM information is set to 0, and the UEQM Gap information is not included in the UEQM Control information. When the wireless communication device 1 applies UEQM, the value of the EQM / UEQM is set to 1, and the UEQM Gap information is included in the UEQM Control information. When the maximum modulation order indicated by the MCS is QPSK, the UEQM Gap information has a length of 1 bit and can indicate the modulation scheme for each spatial stream as the difference from the reference modulation order. When the maximum modulation order indicated by the MCS is 16QAM or greater, the UEQM Gap information has a length of 2 bits and can indicate the modulation scheme for each spatial stream as the difference from the reference modulation order. For example, when the NSS is 4, the UEQM Gap information in this example can indicate the modulation scheme for each spatial stream as the difference from the reference modulation order, as shown in the table of Figure 12. Specifically, when the maximum modulation order indicated by the MCS is QPSK, if the UEQM Gap information is 0, the modulation orders for each spatial stream are the same, and if the UEQM Gap information is 1, the modulation orders for each spatial stream are a combination of M / M / M / M-1. When the maximum modulation order indicated by the MCS is 16QAM or greater, if the UEQM Gap information is 00, the modulation order of each spatial stream is the same; if the UEQM Gap information is 01, the modulation order for each spatial stream is M / M / M / M-1; if the UEQM Gap information is 10, it is M / M / M / M-2; or if the UEQM Gap information is 11, it is M / M / M-1 / M-2.The wireless communication device 2 that receives the UHR-SIG including the UEQM Control information of this example can perform demodulation corresponding to the modulation method for each spatial stream by referring to the EQM / UEQM information, if present, based on the values ​​of NSS and MCS, and further interpreting the UEQM Gap information, if present, based on the relationship shown in Fig. 12. However, the correspondence between the UEQM Gap information and the modulation order does not need to be limited to the format shown in Fig. 12.

[0070] As another example, the User field in the UHR-SIG includes at least an NSS and an MCS, and can include UEQM Code information when the number of spatial streams is two or more and the maximum modulation order indicated by the MCS is QPSK or higher. That is, as shown in FIG. 13 , the User field specifically includes some or all of the elements indicating control information such as the STA-ID, MCS, NSS, UEQM Code, Beamformed, and Coding. The UEQM Code information is variable length and is control information that indicates the combination of modulation orders for each spatial stream depending on its value and bit length. As an example, as shown in the table of FIG. 14 , the index can have a length of 1 to 3 bits and indicate the modulation scheme for each spatial stream in an instantaneously decodable format. Specifically, when NSS is 4, when the value of the UEQM Code information is 0, the modulation order of all spatial streams is M; when the value of the UEQM Code information is 10, the modulation order for each spatial stream is M / M / M / M-1; when the value of the UEQM Code information is 110, the modulation order for each spatial stream is M / M / M / M-2; and when the value of the UEQM Code information is 111, the modulation order for each spatial stream is M / M / M-1 / M-2. The wireless communication device 2 can perform demodulation corresponding to the modulation scheme for each spatial stream based on the relationship in Figure 14 by reading the received UEQM Code information in order from the most significant bit until a 0 appears or up to the third bit, which is the maximum number of bits. However, the correspondence between the UEQM Code information and the modulation order does not need to be limited to the format shown in Figure 14.

[0071] Although the above embodiments have all been described with reference to non-MU-MIMO single-user transmission, multi-user transmission using OFDMA or MU-MIMO may also be used. In the case of OFDMA multi-user transmission, a plurality of User Specific fields in the UHR-SIG are generated according to the number of users, and the destination is specified by identification information (STA-ID) that specifies the target station device and is included in the User field, and the destination is specified by the STA-ID included in the User field. In the case of MU-MIMO multi-user transmission, a plurality of User Specific fields in the UHR-SIG are also generated according to the number of users, and the destination is specified by the STA-ID included in the User field, and the destination is specified by the STA-ID. However, the NSS for each user during MU-MIMO multi-user transmission can be indicated by the value of Spatial Configuration.

[0072] The wireless communication device 1 can notify the wireless communication device 2 of information indicating the recommended modulation method and error correction coding rate for data to be transmitted to the wireless communication device 1, i.e., the recommended data rate, by using a ULA Control subfield included in a management frame, a control frame, or a QoS data frame (based on the value of the +HTC field). In particular, when the wireless communication device 1 and the wireless communication device 2 are UHR STAs that support UEQM, the recommended UEQM information is also included in the ULA Control subfield. The series of procedures from estimating the channel transmission characteristics, determining the above recommended parameters, and notifying other wireless communication devices of them is called link adaptation.

[0073] There are various methods available for determining the recommended parameters by link adaptation. The following is an example. The recommended parameters are selected based on the transmission characteristics stored in a set of parameters related to receiving operation called RXVECTOR by the PPDU for MFB (MCS Feedback) estimation, so that the estimated frame error rate is below a certain level for a specific MPDU length.

[0074] The wireless communication device 1 can inform the wireless communication device 2 whether or not it has the function of UHR link adaptation using the ULA Control subfield by the value of the UHR Link Adaptation Support subfield included in the UHR MAC Capabilities Information field in the UHR Capabilities element.

[0075] An example in which the ULA Control subfield contains recommended UEQM information when wireless communication device 1 performs UHR link adaptation using the ULA Control subfield with wireless communication device 2 will be described in the same manner as for the UHR-SIG. Regarding the third control information, descriptions in the drawings and the like that overlap with the UHR-SIG will be omitted. The ULA Control subfield contains at least information indicating the recommended number of spatial streams (Recommended NSS), and in this example, can contain Recommended UHR-MCS. For example, as shown in FIG. 15 , the ULA Control subfield specifically contains some or all of the elements indicating control information, such as Unsolicited MFB, MRQ / UL UHR TB PPDU MFB, (Recommended) NSS, (Recommended) UHR-MCS, RU allocation, PS 160, BW, MSI / Partial PPDU Parameters, and Tx Beamforming. Note that Unsolicited MFB is information indicating whether the ULA Control subfield is an MFB for which no ULA Control subfield is required. Furthermore, MRQ / UL UHR TB PPDU MFB is information indicating a request or response for feedback to link adaptation, or a target frame for recommended parameters. Furthermore, RU allocation is information indicating the allocation of resource units (RUs). An RU is an allocation unit of a wireless communication device, consisting of multiple subcarriers. PS 160 is information indicating the channel to which the RU is allocated. Furthermore, BW is information indicating the recommended bandwidth. Furthermore, MSI / Partial PPDU Parameters is information indicating a sequence number related to the feedback request. Furthermore, Tx Beamforming is information indicating whether beamforming is implemented. Recommended UHR-MCS is control information indicating the modulation method for each spatial stream and the error correction coding rate common to the spatial streams, and the range of possible values ​​can be changed based on the Recommended NSS.The UHR-MCS index shown in the table of Figure 7 can also be applied to the Recommended UHR-MCS, in which case NSS represents the Recommended NSS. That is, this is an example when the Recommended NSS is 4 and the maximum difference between the modulation orders of each spatial stream is 2. Wireless communication device 2 that receives a frame including the ULA Control subfield can interpret the Recommended UHR-MCS based on, for example, the relationship shown in Figure 7, and know the application form of the UEQM recommended for communication with wireless communication device 1. However, the range of Recommended UHR-MCS values, the index corresponding to that range, the combination of modulation orders, and the coding rate do not all need to be limited to the format shown in Figure 7.

[0076] Next, an example will be described in which the ULA Control subfield includes at least Recommended NSS, information indicating a recommended MCS (Recommended MCS), and Recommended UEQM Gap information. As shown in Figure 16, the ULA Control subfield specifically includes some or all of the elements indicating control information such as Unsolicited MFB, MRQ / UL UHR TB PPDU MFB, (Recommended) NSS, (Recommended) MCS, (Recommended) UEQM Gap, RU allocation, PS 160, BW, MSI / Partial PPDU Parameters, and Tx Beamforming. The Recommended UEQM Gap information is control information in which the modulation scheme indicated by Recommended MCS is used as the reference modulation order M, and the modulation scheme for each spatial stream based on the Recommended NSS is indicated as the difference from the reference modulation order. The example of UEQM Gap information shown in the table of Figure 9 can also be applied to Recommended UEQM Gap information, and in that case, NSS represents Recommended NSS. The wireless communication device 2 that receives the frame including the ULA Control subfield can interpret the Recommended UEQM Gap information based on the relationship shown in Fig. 9 and know the application form of the UEQM recommended for communication with the wireless communication device 1. However, the correspondence relationship between the Recommended UEQM Gap information and the modulation order does not need to be limited to the format shown in Fig. 9.

[0077] Below, an example will be described in which the ULA Control subfield includes at least the Recommended NSS and Recommended MCS, and further includes variable-length control information regarding the UEQM recommended depending on conditions.

[0078] For example, the ULA Control subfield further includes at least Recommended NSS, Recommended MCS, and Recommended UEQM Control information. That is, as shown in FIG. 17 , the ULA Control subfield specifically includes some or all of the elements indicating control information such as Unsolicited MFB, MRQ / UL UHR TB PPDU MFB, (Recommended) NSS, (Recommended) MCS, (Recommended) UEQM Control, RU allocation, PS 160, BW, MSI / Partial PPDU Parameters, and Tx Beamforming. The Recommended UEQM Control information is composed of EQM / UEQM information, or EQM / UEQM information and Recommended UEQM Gap information. When wireless communication device 1 recommends a modulation scheme common to all spatial streams to wireless communication device 2, the value of EQM / UEQM is set to 0, and Recommended UEQM Gap information is not included in the Recommended UEQM Control information. On the other hand, when wireless communication device 1 recommends UEQM to wireless communication device 2, the value of EQM / UEQM is set to 1, and Recommended UEQM Gap information is included in the Recommended UEQM Control information. The UEQM Gap information can indicate the modulation scheme for each spatial stream as the difference from the reference modulation order indicated by the Recommended MCS. The example of UEQM Gap information shown in the table of FIG. 11 can also be applied to Recommended UEQM Gap information, and in that case, NSS represents Recommended NSS. When wireless communication device 2 receives a ULA Control subfield including the Recommended UEQM Control information of this example, it references the value of the EQM / UEQM information and, if Recommended UEQM Gap information is present, interprets it based on the relationship shown in FIG. 11, thereby being able to know the application form of the UEQM recommended for communication with wireless communication device 1.However, the correspondence between the Recommended UEQM Gap information and the modulation order does not need to be limited to the format shown in FIG.

[0079] In another example, the ULA Control subfield includes at least Recommended NSS and Recommended MCS, and can include Recommended UEQM Control information when the value of Recommended NSS is 2 or greater and the maximum modulation order indicated by Recommended MCS is QPSK or greater (see FIG. 17). The Recommended UEQM Control information is composed of EQM / UEQM information, or EQM / UEQM information and Recommended UEQM Gap information. When wireless communication device 1 recommends a modulation scheme common to all spatial streams to wireless communication device 2, the value of EQM / UEQM is set to 0, and Recommended UEQM Gap information is not included in the Recommended UEQM Control information. On the other hand, when wireless communication device 1 recommends UEQM to wireless communication device 2, the value of EQM / UEQM is set to 1, and Recommended UEQM Gap information is included in the Recommended UEQM Control information. The Recommended UEQM Gap information can indicate the modulation scheme for each spatial stream as a difference from the reference modulation order, for example, as shown in the table of FIG. 11. Specific combinations are the same as those in the above example. The wireless communication device 2 that has received the ULA Control subfield including the Recommended UEQM Control information of this example refers to the value of EQM / UEQM information if it exists based on the values ​​of Recommended NSS and Recommended MCS, and further interprets Recommended UEQM Gap information if it exists based on the relationship shown in Fig. 11, thereby being able to know the application form of the UEQM recommended for communication with the wireless communication device 1. However, the correspondence relationship between the Recommended UEQM Gap information and the modulation order does not need to be limited to the format shown in Fig. 11.

[0080] In another example, the ULA Control subfield includes at least Recommended NSS and Recommended MCS, and can include Recommended UEQM Control information when the value of Recommended NSS is 2 or greater and the maximum modulation order indicated by Recommended MCS is QPSK or greater (FIG. 17). The Recommended UEQM Control information is composed of EQM / UEQM information, or EQM / UEQM information and Recommended UEQM Gap information. When wireless communication device 1 recommends a modulation scheme common to all spatial streams to wireless communication device 2, the value of EQM / UEQM is set to 0, and Recommended UEQM Gap information is not included in the Recommended UEQM Control information. On the other hand, when wireless communication device 1 recommends UEQM to wireless communication device 2, the value of EQM / UEQM is set to 1, and Recommended UEQM Gap information is included in the Recommended UEQM Control information. When the maximum modulation order indicated by Recommended MCS is QPSK, the Recommended UEQM Gap information has a length of 1 bit and can indicate the modulation scheme for each spatial stream as the difference from the reference modulation order. When the maximum modulation order indicated by the Recommended MCS is 16QAM or higher, the Recommended UEQM Gap information has a length of 2 bits and can indicate the modulation scheme for each spatial stream as the difference from the reference modulation order. The Recommended UEQM Gap information in this example is expressed as shown in the table of Figure 12 when the Recommended NSS is 4, for example. When the wireless communication device 2 receives the ULA Control subfield including the Recommended UEQM Control information in this example, the wireless communication device 2 refers to the value of EQM / UEQM information if present based on the values ​​of the Recommended NSS and Recommended MCS, and further interprets the Recommended UEQM Gap information if present based on the relationship shown in Figure 12, thereby being able to know the application form of the UEQM recommended for communication with the wireless communication device 1.However, the correspondence between the Recommended UEQM Gap information and the modulation order does not need to be limited to the format shown in FIG.

[0081] As another example, the ULA Control subfield includes at least a Recommended NSS and a Recommended MCS, and can include Recommended UEQM Code information when the Recommended NSS is 2 or greater and the maximum modulation order indicated by the Recommended MCS is QPSK or greater. That is, as shown in Figure 18, the ULA Control subfield specifically includes some or all of the elements indicating control information such as Unsolicited MFB, MRQ / UL UHR TB PPDU MFB, (Recommended) NSS, (Recommended) MCS, (Recommended) UEQM Code, RU allocation, PS 160, BW, MSI / Partial PPDU Parameters, and Tx Beamforming. The Recommended UEQM Code information is variable length and is control information that indicates the combination of modulation orders for each spatial stream depending on its value and bit length. The example of UEQM Code information shown in the table of Figure 14 can also be applied to Recommended UEQM Code information, and in that case, NSS represents Recommended NSS. That is, an example of the Recommended UEQM Code information has a length of 1 to 3 bits and can indicate the modulation method for each spatial stream in an instantaneously decodable format. The wireless communication device 2 can know the application form of the UEQM recommended for communication with the wireless communication device 1 based on the relationship in Figure 14 by reading the Recommended UEQM Code information in the received ULA Control subfield in order from the most significant bit until a 0 appears or up to the third bit, which is the maximum number of bits. However, the correspondence between the Recommended UEQM Code information and the modulation order does not need to be limited to the format shown in Figure 14.

[0082] In addition, an embodiment in which the User field in the UHR-SIG in non-MU-MIMO single-user transmission includes at least NSS, MCS, and EQM / UEQM information will be described below. Specifically, the User field includes all or some of the elements indicating control information, such as STA-ID, MCS, NSS, EQM / UEQM, and Beamformed. When the value of the EQM / UEQM information indicates the application of UEQM, the User field includes UEQM Gap information. For example, when NSS is 2, the UEQM Gap information has a length of 1 bit and can indicate the modulation scheme for each spatial stream as the difference from the reference modulation order. The modulation order is sometimes referred to as a constellation index. When NSS is 3 or greater, the UEQM Gap information has a length of 2 bits and can indicate the modulation scheme for each spatial stream as the difference from the reference modulation order. As a specific example, when NSS is 2, the UEQM Gap information has a length of 1 bit, and if its value is 0, it indicates that the modulation order for each spatial stream is M / M-1, and if it is 1, it indicates that the modulation order for each spatial stream is M / M-2. Specifically, when NSS is 3 or more, the UEQM Gap information has a length of 2 bits, and if its value is 00, it indicates that the modulation order from the first stream to the (NSS-1)th stream is M and the modulation order of the NSS stream is M-1, if it is 01, it indicates that the modulation order from the first stream to the (NSS-1)th stream is M and the modulation order of the NSS stream is M-2, and if it is 10, it indicates that the modulation order from the first stream to the (NSS-2)th stream is M, the modulation order of the (NSS-1)th stream is M-1, and the modulation order of the NSS stream is M-2. If NSS is 4 or more, when the value of the UEQM Gap information is 11, it can be indicated that the modulation order from the first stream to the (NSS-3) stream is M, the modulation order of the (NSS-2) stream and the (NSS-1) stream is M-1, and the modulation order of the NSS stream is M-2.The wireless communication device 2 that receives the UHR-SIG in this example refers to the values ​​of the EQM / UEQM information and, if UEQM Gap information is present, interprets it based on the above relationship to identify the number of spatial streams and perform demodulation corresponding to the modulation method for each spatial stream. However, the correspondence between the UEQM Gap information and the number of spatial streams and modulation order does not need to be limited to the format shown above.

[0083] Alternatively, the UEQM Gap information in the above example may have a length of 1 bit when, for example, NSS is 2 or another specific condition is satisfied, and indicate the modulation scheme for each spatial stream as a difference from the reference modulation order. On the other hand, when NSS is 3 or greater and the other specific condition is not satisfied, the UEQM Gap information may have a length of 2 bits and indicate the modulation scheme for each spatial stream as a difference from the reference modulation order. The other specific condition may be, for example, "the reference modulation order indicated by the MCS is QPSK." In this case, the UEQM Gap information can indicate the modulation scheme for each spatial stream as follows, for example: That is, when NSS is 2 or the reference modulation order indicated by the MCS is QPSK, if the value of the UEQM Gap information is 0, the modulation order from the first stream to the (NSS-1)th stream is M and the modulation order of the NSS stream is M-1; and if the value of the UEQM Gap information is 1, the modulation order from the first stream to the (NSS-1)th stream is M and the modulation order of the NSS stream is M-2. On the other hand, when NSS is 3 or more and the reference modulation order indicated by MCS is 16QAM or more, the UEQM Gap information has a length of 2 bits and indicates the modulation method for each spatial stream. Specifically, when NSS is 3 or more, the UEQM Gap information has a length of 2 bits, and if its value is 00, it indicates that the modulation order from the first stream to the (NSS-1)th stream is M and the modulation order of the NSS stream is M-1; if its value is 01, it indicates that the modulation order from the first stream to the (NSS-1)th stream is M and the modulation order of the NSS stream is M-2; and if it is 10, it indicates that the modulation order from the first stream to the (NSS-2)th stream is M, the modulation order of the (NSS-1)th stream is M-1, and the modulation order of the NSS stream is M-2. If NSS is 4 or more, when the value of the UEQM Gap information is 11, it can be indicated that the modulation order from the first stream to the (NSS-3) stream is M, the modulation order of the (NSS-2) stream and the (NSS-1) stream is M-1, and the modulation order of the NSS stream is M-2.The wireless communication device 2 that receives the UHR-SIG in this example references the values ​​of the EQM / UEQM information and, if UEQM Gap information is present, interprets it based on the above relationship to identify the number of spatial streams and perform demodulation corresponding to the modulation method for each spatial stream. However, the correspondence between the UEQM Gap information and the number of spatial streams and modulation order does not need to be limited to the format shown above. The number of bits of the UQEM Gap information may be changed depending on whether the NSS value is 3 or greater, or the number of bits of the UQEM Gap information may be changed depending on whether the NSS value is 4 or greater. A larger number of bits may be allocated to the UQEM Gap information when the NSS value is large, and a larger number of bits may be allocated to the UQEM Gap information when the NSS value is small.

[0084] Next, an embodiment will be described in which the User field in the UHR-SIG for non-MU-MIMO single-user transmission includes at least MCS and EQM / UEQM information, and when the value of the EQM / UEQM information indicates the application of UEQM, the User field also includes NSS and UEQM Gap Set information. The NSS and UEQM Gap Set information is control information indicating the number of spatial streams and the modulation scheme for each spatial stream. The modulation scheme for each spatial stream is indicated as the difference from the reference modulation order indicated by the MCS. Specifically, the User field is configured to include all or some of the elements indicating control information such as STA-ID, MCS, EQM / UEQM, NSS and UEQM Gap Set, and Beamformed (FIG. 19). The NSS and UEQM Gap Set information has a length of 4 bits, for example, as shown in FIG. 20 , and if its value is 0000 or 0001, it indicates that the NSS is 2 and the modulation orders for each spatial stream are M / M-1 and M / M-2, respectively; if its value is 0010, 0011, or 0100, it indicates that the NSS is 3 and the modulation orders for each spatial stream are M / M / M-1, M / M / M-2, or M / M-1 / M-2, respectively; and if its value is 0101, 0110, 0111, or 1000, it indicates that the NSS is 4 and the modulation orders for each spatial stream are M / M / M / M-1, M / M / M / M-2, M / M / M-1 / M-2, or M / M-1 / M-1 / M-2, respectively. The wireless communication device 2 that receives the UHR-SIG in this example refers to the values ​​of the EQM / UEQM information, and if NSS and UEQM Gap Set information is present, interprets it based on the above relationship shown in Figure 20, thereby identifying the number of spatial streams and enabling demodulation corresponding to the modulation method for each spatial stream.

[0085] Alternatively, the NSS and UEQM Gap Set information may indicate the number of spatial streams and the modulation order for each spatial stream, as in the following example: That is, when the value of the NSS and UEQM Gap Set information is 0, 1, ..., 6, the NSS is 2, 3, ..., 8, respectively, which indicates that the modulation order for the first stream to the (NSS-1)th stream is M and the modulation order for the NSS stream is M-1. Also, when the value of the NSS and UEQM Gap Set information is 7, 8, ..., 13, the NSS is 2, 3, ..., 8, respectively, which indicates that the modulation order for the first stream to the (NSS-1)th stream is M and the modulation order for the NSS stream is M-2. Similarly, the number of spatial streams and the modulation order for each spatial stream can be indicated within the range of subsequent possible values ​​( FIG. 21 ). The wireless communication device 2 that has received the UHR-SIG of this example refers to the values ​​of the EQM / UEQM information, and if NSS and UEQM Gap Set information is present, interprets it based on the above relationship shown in Fig. 21, thereby identifying the number of spatial streams and enabling demodulation corresponding to the modulation method for each spatial stream. However, the correspondence between the above-mentioned NSS and UEQM Gap Set information and the number of spatial streams and modulation order does not need to be limited to the format shown in Figs. 20 and 21.

[0086] In the above embodiments, non-MU-MIMO single-user transmission has been described as an example, but multi-user transmission using OFDMA or MU-MIMO may also be used. In the case of OFDMA multi-user transmission, a plurality of User Specific fields in the UHR-SIG are generated according to the number of users, and the destination is specified by the STA-ID included in the User field in the User Specific field before transmission. In the case of MU-MIMO multi-user transmission, a plurality of User Specific fields in the UHR-SIG are generated according to the number of users, and the destination is specified by the STA-ID included in the User field in the User Specific field before transmission. However, the NSS for each user during MU-MIMO multi-user transmission may be indicated by the value of Spatial Configuration. In either case, part or all of the control information according to the embodiments of the present invention may be generated and transmitted independently for each user.

[0087] Also, a case will be described in which the ULA Control subfield contains recommended UEQM information when wireless communication device 1 performs UHR link adaptation using the ULA Control subfield with wireless communication device 2. Duplicate explanations, such as those related to the drawings, will be omitted.

[0088] In this embodiment, the ULA Control subfield includes at least information indicating a recommended MCS (Recommended MCS). For example, the ULA Control subfield specifically includes some or all of the elements indicating control information, such as Unsolicited MFB, MRQ / UL UHR TB PPDU MFB, (Recommended) NSS, (Recommended) MCS, RU allocation, PS 160, BW, MSI / Partial PPDU Parameters, and Tx Beamforming. If the Unsolicited MFB information indicates that the ULA Control subfield is not required, the ULA Control subfield can include Recommended EQM / UEQM information. If the ULA Control subfield includes Recommended EQM / UEQM information and the value of the EQM / UEQM information indicates the application of UEQM, the ULA Control subfield includes Recommended UEQM Gap information. For example, when NSS is 2, the Recommended UEQM Gap information has a length of 1 bit and can indicate the modulation scheme for each spatial stream as the difference from the reference modulation order. In this case, when the NSS is 3 or greater, the UEQM Gap information may have a length of 2 bits and indicate the modulation scheme for each spatial stream as a difference from the reference modulation order. Alternatively, the Recommended UEQM Gap information may have a length of 1 bit and indicate the modulation scheme for each spatial stream as a difference from the reference modulation order when, for example, the NSS is 2 or another specific condition is met. On the other hand, when the NSS is 3 or greater and the other specific condition is not met, the Recommended UEQM Gap information may have a length of 2 bits and indicate the modulation scheme for each spatial stream as a difference from the reference modulation order. The other specific condition may be, for example, "the modulation order indicated by the MCS (or the reference modulation order) is QPSK." One form that the Recommended UEQM Gap information can take in the above case is similar to the example of the UEQM Gap information included in the UHR-SIG, but implementation need not be limited to this form.When the wireless communication device 2 receives the ULA Control subfield containing the Recommended UEQM Gap information in this example, it refers to the value of Recommended EQM / UEQM information if it exists, and if Recommended UEQM Gap information exists, it interprets it based on the relationship shown above, thereby being able to know the UEQM pattern recommended for communication with the wireless communication device 1.

[0089] Furthermore, if the Unsolicited MFB information indicates that the ULA Control subfield is not an unrequired MFB, the ULA Control subfield with a similar configuration may not include Recommended EQM / UEQM information. If the ULA Control subfield does not include Recommended EQM / UEQM information, when the received ULA request indicates that UEQM is to be applied during data transmission, the ULA Control subfield includes Recommended UEQM Gap information. The Recommended UEQM Gap information may have a length of 1 bit when NSS is 2, for example, and may indicate the modulation scheme for each spatial stream as the difference from the reference modulation order. In this case, when NSS is 3 or greater, the UEQM Gap information may have a length of 2 bits and indicate the modulation scheme for each spatial stream as the difference from the reference modulation order. Alternatively, the Recommended UEQM Gap information may have a length of 1 bit when, for example, NSS is 2 or another specific condition is met, and indicate the modulation scheme for each spatial stream as the difference from the reference modulation order. On the other hand, when NSS is 3 or greater and the other specific condition is not met, the Recommended UEQM Gap information may have a length of 2 bits and indicate the modulation scheme for each spatial stream as the difference from the reference modulation order. The other specific condition may be, for example, "the reference modulation order indicated by the MCS is QPSK." In the above case, one form that the Recommended UEQM Gap information can take is similar to the example of the UEQM Gap information included in the UHR-SIG, but implementation is not limited to this one form. Upon receiving the ULA Control subfield of this example, the wireless communication device 2 references the value of Recommended EQM / UEQM information if present, and interprets the Recommended UEQM Gap information based on the relationship shown above if present, thereby determining the UEQM pattern recommended for communication with the wireless communication device 1.

[0090] In another example, when the application of UEQM during data transmission is indicated by either the ULA Control subfield, which is an unrequested MFB, or a received ULA request, the ULA Control subfield includes Recommended NSS and UEQM Gap Set information. The Recommended NSS and UEQM Gap Set information is control information indicating the recommended number of spatial streams and the recommended modulation scheme for each spatial stream. The recommended modulation scheme for each spatial stream is indicated as the difference from the reference modulation order indicated by the Recommended MCS. In the above case, one form that the Recommended NSS and UEQM Gap Set information can take is similar to the example of the NSS and UEQM Gap Set information included in the UHR-SIG, but implementation is not limited to this one form. Upon receiving the ULA Control subfield in this example, the wireless communication device 2 references the value of Recommended EQM / UEQM information if present, and interprets Recommended NSS and UEQM Gap information if present based on the relationship described above, thereby being able to know the recommended number of spatial streams and UEQM pattern for communication with the wireless communication device 1.

[0091] The wireless communication device according to the present invention can communicate in a frequency band (frequency spectrum) that does not require permission to use from a country or region, which is called an unlicensed band, but the usable frequency band is not limited to this. For example, the wireless communication device according to the present invention can also be effective in a frequency band called a white band (for example, a frequency band allocated for television broadcasting but unused in some regions) that is not actually used despite permission to use it for a specific service from a country or region for the purpose of preventing interference between frequencies, or in a shared spectrum (shared frequency band) that is expected to be shared by multiple operators.

[0092] The program running on the wireless communication device according to the present invention is a program that controls the CPU and other components (programs that cause a computer to function) to implement the functions of the above-described embodiments of the present invention. Information handled by these devices is temporarily stored in RAM during processing, then stored in various ROMs or HDDs, and read, modified, and written by the CPU as needed. Recording media for storing the program may include semiconductor media (e.g., ROM, non-volatile memory cards, solid-state drives, etc.), optical recording media (e.g., DVDs, MOs, MDs, CDs, BDs, etc.), and magnetic recording media (e.g., magnetic tapes, flexible disks, etc.). Executing a loaded program not only implements the functions of the above-described embodiments, but may also implement the functions of the present invention by processing in cooperation with an operating system or other application programs based on instructions from the program.

[0093] Furthermore, when distributing the program on the market, the program can be stored and distributed on a portable recording medium or transferred to a server computer connected via a network such as the Internet. In this case, the storage device of the server computer also falls within the scope of the present invention. Furthermore, part or all of the wireless communication device in the above-described embodiments may be realized as an LSI, which is typically an integrated circuit. Each functional block of the wireless communication device may be individually formed into a chip, or part or all of the functional blocks may be integrated into a chip. When each functional block is formed into an integrated circuit, an integrated circuit control unit that controls them is added. It goes without saying that the present invention also includes cases where programs and setting information are downloaded from a server computer to implement at least part of the functions of the above-described embodiments.

[0094] Furthermore, the integrated circuit method is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology, it may also be possible to use an integrated circuit based on that technology.

[0095] It should be noted that the present invention is not limited to the above-described embodiments. The wireless communication device of the present invention is not limited to application to mobile station devices, but can of course be applied to stationary or non-movable electronic devices installed indoors or outdoors, such as AV equipment, kitchen equipment, cleaning / washing equipment, air conditioning equipment, office equipment, vending machines, and other household appliances.

[0096] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and designs that do not deviate from the gist of the present invention are also included in the scope of the claims.

[0097] The present invention is suitable for use in a wireless communication device and a communication method.

[0098] 100-1, 100-2 Basic service set 101-1, 101-2 Access point device 102-1, 102-2 Terminal device 103-1, 103-2 Legacy terminal device 400 Wireless communication device 401 Upper layer unit 402 Communication control unit 403 Wireless transmission unit 404 Wireless reception unit 405 Carrier sense unit 406 Antenna unit

Claims

1. A wireless communication device comprising: a control unit that generates first control information; and a transmission unit that transmits the first control information, wherein the first control information includes at least information indicating a modulation scheme and an error correction coding rate (MCS: Modulation and Coding Scheme), information indicating the number of spatial streams (NSS: Number of Spatial Streams), and second control information, wherein the second control information is information indicating whether the modulation schemes applied to each of the spatial streams are all the same, and when the second control information indicates that the modulation schemes for each of the spatial streams are not all the same, the first control information includes third control information, wherein the third control information indicates a modulation scheme for each of the spatial streams and includes, based on at least the NSS, information indicating a reference modulation order in the spatial streams and information indicating a difference from the reference modulation order, and the reference modulation order is the modulation order of the modulation scheme indicated by the MCS.

2. The wireless communication device according to claim 1, characterized in that the third control information has an information amount of 1 bit when the reference modulation order is a certain value, and 2 bits when the reference modulation order is any other value.

3. The wireless communication device according to claim 1, characterized in that the third control information has an information volume of 1 bit if a condition is met and 2 bits otherwise, and the condition includes at least that the NSS is a certain value.

4. The wireless communication device according to claim 3, characterized in that the third control information has an information volume of 1 bit when the NSS is a certain value or when the reference modulation order is a certain value, and has an information volume of 2 bits when the NSS and the reference modulation order are other values.

5. A communication method comprising: a step of generating first control information; and a step of transmitting the first control information, wherein the first control information includes at least information indicating a modulation scheme and an error correction coding rate (MCS), information indicating the number of spatial streams (NSS), and second control information, wherein the second control information is information indicating whether the modulation schemes applied to each of the spatial streams are all the same, and when the second control information indicates that the modulation schemes for each of the spatial streams are not all the same, the first control information includes third control information, wherein the third control information indicates a modulation scheme for each of the spatial streams and includes, based on at least the NSS, information indicating a reference modulation order in the spatial stream and information indicating a difference from the reference modulation order, and the reference modulation order is the modulation order of the modulation scheme indicated by the MCS.

Images