Communication device and communication method

Abstract

According to the present invention, one or more user groups including one or more terminal devices among the plurality of terminal devices are set, one or more sub-user groups that can communicate between the terminal devices are set, each of the sub-user groups is a subset of one of the one or more user groups, and a transmission period is acquired all at once for some or all of the sub-user groups, the transmission unit transmits a control frame and a data frame within the transmission period, the control frame includes the timing at which the data frame is transmitted in each of the terminal devices included in at least one of the sub-user groups, and the transmission timing is one of a plurality of timings set within the transmission period.

Description

Communication device and communication method

[0001] This application claims priority to Japanese Patent Application No. 2023-220663 filed in Japan on December 27, 2023, Japanese Patent Application No. 2024-31885 filed in Japan on March 4, 2024, and Japanese Patent Application No. 2024-63830 filed in Japan on April 11, 2024, the contents of which are incorporated herein by reference.

[0002] The number of industrial robots installed worldwide is increasing every year, and it is expected that the number of robots with various roles will increase in the future. Robots are particularly expected to address labor shortages due to population decline, and to perform tasks on behalf of humans, such as working in areas that are difficult for humans to perform (such as underwater) or for long periods of time. The tasks required of robots will become increasingly sophisticated and complex in the future, and this is likely to be achieved not only through the development of high-performance robots but also through the cooperative work of multiple robots. For cooperative work by multiple robots, the robots must exchange information with each other to complete the task. Robots are described, for example, in Non-Patent Document 1. Wireless LANs (Local Area Networks) are one method for exchanging information between robots. Wireless LANs enable wireless communication using unlicensed bands that can be used without permission (licenses) from national or local governments.

[0003] one6G white paper, “6G & ROBOTICS, Use Cased and Potential Service Requirements”, June 2023.

[0004] However, when robots work cooperatively, the information exchange between the robots must be carried out within a certain period of time, and highly reliable communication is desirable. The present invention has been made in consideration of such circumstances, and its object is to provide a communication device and a communication method that enable highly reliable information exchange between multiple terminal devices (communication devices).

[0005] The communication device and communication method according to the present invention for solving the above-mentioned problems are as follows.

[0006] That is, a communication device according to one embodiment of the present invention is a communication device that communicates with one or more terminal devices, and is equipped with a control unit and a transmission unit, wherein the control unit sets one or more user groups including one or more terminal devices among the plurality of terminal devices, and sets one or more sub-user groups for the user group, each of the sub-user groups being a subset of any of the one or more user groups, and sets a transmission period at one time for some or all of the sub-user groups, and the transmission unit transmits a control frame and a data frame within the transmission period, and the control frame includes transmission timing of the data frame for each of the terminal devices included in at least any of the sub-user groups, and the transmission timing is one of a plurality of timings set within the transmission period, and the transmission period is either a TXOP or a service period.

[0007] In addition, in a communication device according to one aspect of the present invention, the device further includes a receiving unit, wherein the control frame includes timing information for receiving the data frame, and the receiving unit receives the control frame and data frame of each of the user groups within the transmission period based on the timing information.

[0008] In addition, in a communication device according to one aspect of the present invention, the data frame includes information indicating whether the task can be completed, and if information indicating that the task cannot be completed is received, information indicating that the task should be suspended is notified.

[0009] In a communication device according to an aspect of the present invention, the receiving unit receives information indicating a request to set a plurality of timings within a transmission period from the terminal device.

[0010] In addition, in a communication device according to one aspect of the present invention, communication is performed with the terminal device via a multi-link, and the transmission period and multiple timings within the transmission period are aligned in at least two links that make up the multi-link.

[0011] In a communication device according to an aspect of the present invention, the terminal devices set in the sub-user group are terminal devices that are permitted to communicate during the transmission period.

[0012] Furthermore, a communication method in a communication device according to one aspect of the present invention is a communication method in a communication device that communicates with one or more terminal devices, comprising a control step and a transmission step, wherein the control step sets one or more user groups including one or more terminal devices among the plurality of terminal devices, sets one or more sub-user groups for the user group, each of the sub-user groups being a subset of any of the one or more user groups, and sets a transmission period at one time for some or all of the sub-user groups, and the transmission step transmits a control frame and a data frame within the transmission period, the control frame including a transmission timing of the data frame in each of the terminal devices included in at least any of the sub-user groups, the transmission timing being one of a plurality of timings set within the transmission period, and the transmission period being either a TXOP or a service period.

[0013] According to the present invention, by using at least one link, it becomes possible to exchange information between a plurality of terminal devices (communication devices) with high reliability.

[0014] 1 is a diagram showing an example of a MAC layer frame configuration related to a wireless LAN system. FIG. 2 is a diagram showing an example of a PPDU configuration related to a wireless LAN system. FIG. 3 is a diagram showing an example of a sounding procedure related to a wireless LAN system. FIG. 4 is a diagram showing an example of a configuration of a communication system according to an aspect of the present invention. FIG. 5 is a block diagram showing an example of a configuration of a station device according to an aspect of the present invention. FIG. 6 is a block diagram showing an example of a configuration of an access point device according to an aspect of the present invention. FIG. 7 is a block diagram showing an example of a configuration of a wireless communication device according to an aspect of the present invention. FIG. 8 is a block diagram showing an example of a configuration of a wireless communication device according to an aspect of the present invention. FIG. 9 is a diagram showing an example of a user group according to an aspect of the present invention. FIG. 10 is a diagram showing an example of a sub-user group according to an aspect of the present invention. FIG. 11 is a diagram showing an example of transmission and reception timing for each link and each station according to an aspect of the present invention. FIG. 12 is a diagram showing an example of a transmission procedure in R-TWT according to an aspect of the present invention. FIG. 13 is a diagram showing an example of a setting pattern of a sub-period in R-TWT according to an aspect of the present invention. FIG. 14 is a diagram showing an example of a transmission procedure in the case of multi-link in R-TWT according to an aspect of the present invention.

[0015] The wireless communication system in this embodiment includes an access point device (also referred to as an AP or base station device) and multiple station devices (also referred to as STAs or terminal devices). The communication system and network configured with the access point device and the station devices are referred to as a basic service set (BSS, management range). The station 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 station device. Therefore, hereinafter, when simply referring to a communication device or a wireless communication device, the communication device or wireless communication device can refer to both the access point device and the station device.

[0016] The access point device and station devices within the BSS communicate based on CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance). This embodiment focuses on infrastructure mode, in which an access point device communicates with multiple station devices. However, the method of this embodiment can also be implemented in ad hoc mode, in which station devices communicate directly with each other. In ad hoc mode, a single station 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 station device forming an IBSS in ad hoc mode can also be considered an access point device. The method of this embodiment can also be implemented in Wi-Fi Direct (registered trademark), in which station devices communicate directly with each other. In Wi-Fi Direct, one station device acts as an access point device to form a group. This station device is called a group owner and can also be considered an access point device.

[0017] In the IEEE 802.11 system, each device can transmit multiple types of frames (communication frames) with a common frame format, which are defined in the physical (PHY) layer, medium access control (MAC) layer, and logical link control (LLC) layer.

[0018] A PHY layer frame is called a physical protocol data unit (PPDU, PHY layer frame). A PPDU is composed of a physical layer header (PHY header) 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 be composed of an aggregated MPDU (A-MPDU), which aggregates multiple MAC protocol data units (MPDU, MAC layer frames), which serve as retransmission units in wireless sections.

[0019] The PHY header includes reference signals such as a short training field (STF) used for signal detection and synchronization, and a long training field (LTF) used to acquire channel information for data demodulation, as well as control signals such as a signal (SIG) containing control information for data demodulation. Furthermore, STF is classified into Legacy-STF (L-STF), High Throughput-STF (HT-STF), Very High Throughput-STF (VHT-STF), High Efficiency-STF (HE-STF), Extremely High Throughput-STF (EHT-STF), etc. depending on the corresponding standard, and LTF and SIG are similarly classified into L-LTF, HT-LTF, VHT-LTF, HE-LTF, L-SIG, HT-SIG, VHT-SIG, HE-SIG, and EHT-SIG. 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. In addition, a Universal SIGNAL (U-SIG) field containing additional control information may be included, assuming technology updates within the same standard.

[0020] Furthermore, the PHY header can include information for identifying the BSS that is the sender of the frame (hereinafter also referred to as BSS identification information). The information for identifying the BSS can 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 for identifying the BSS can 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 can be included in the HE-SIG-A or U-SIG.

[0021] The PPDU is modulated according to the corresponding standard, for example, in the case of the IEEE 802.11n standard, it is modulated into an Orthogonal Frequency Division Multiplexing (OFDM) signal.

[0022] An MPDU consists of a MAC header containing information for signal processing at the MAC layer, a MAC Service Data Unit (MSDU) or frame body, which is a data unit processed at the MAC layer, and a Frame Check Sequence (FCS), which checks whether the frame is error-free (see Figure 1). Multiple MSDUs can also be aggregated as an Aggregated MSDU (A-MSDU).

[0023] Frame types in the MAC layer are broadly classified into three types: management frames that manage the connection status between devices, control frames that manage the communication status between 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. BlockAck 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. Data frames include data frames and polling (CF-poll) frames. Each device can recognize the frame type and subframe type of a received frame by reading the contents of the frame control field included in the MAC header.

[0024] A beacon frame includes a field indicating the period (beacon interval) at which the beacon is transmitted and the SSID. An access point device can periodically broadcast a beacon frame within a BSS, and a station device can recognize surrounding access point devices by receiving the beacon frame. The act of a station device recognizing an access point device based on a beacon frame broadcast by an access point device is called passive scanning. On the other hand, the act of a station device searching for an access point device by broadcasting a probe request frame within a BSS is called active scanning. An 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.

[0025] After recognizing an access point device, a station device performs a connection process with the access point device. The connection process is classified into an authentication procedure and an association procedure. The station device transmits an authentication request frame to the access point device with which it wishes to connect. Upon receiving the authentication request frame, the access point device transmits an authentication response frame to the station device, the authentication response frame including a status code indicating whether the station device has been authenticated. The station 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 station device can exchange authentication request frames and authentication response frames (both of which are collectively referred to as authentication frames) multiple times.

[0026] Following the authentication procedure, the station 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 connection of the station device and transmits a connection response frame to notify the determination. The connection response frame contains a status code indicating whether the connection process is successful, as well as an association identifier (AID) for identifying the station device. The access point device can manage multiple station devices by setting different AIDs for each station device to which it has issued connection permission.

[0027] After the connection process is completed, the access point device and the station device perform actual data transmission. In the IEEE 802.11 system, the Distributed Coordination Function (DCF), the Point Coordination Function (PCF), and their extended Hybrid Coordination Function (HCF) are defined as media access methods. Specific implementation methods of the HCF include Enhanced Distributed Channel Access (EDCA) and HCF Controlled Channel Access (HCCA).

[0028] First, an example of the operation when an access point device transmits a signal to a station device based on DCF will be described. In DCF, the access point device and the station device perform carrier sense (CS) to check the usage status of the wireless channel around the device before communication. For example, if an access point device or a station 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 access point device or the station 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, 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. In this way, CS performed by each device based on the power level of the signal actually received is referred to as physical carrier sense (physical CS). The CCA level is also referred to as the carrier sense level (CS level) or the CCA threshold (CCAT). When the access point device and station device detect a signal with a reception power equal to or higher than the CCA level, they begin to demodulate at least the PHY layer signal.

[0029] An access point device performs carrier sensing during an interframe space (IFS) period set according to the type of frame to be transmitted, and determines whether the wireless channel is busy or idle. The period during which the access point device performs carrier sensing varies depending on the frame type and subframe type of the frame to be transmitted. The IEEE 802.11 system defines multiple IFS periods 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 access point device uses the DIFS.

[0030] After waiting for the DIFS period, the access point 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 each transmitting station waiting for a randomly set time before starting transmission. When the access point 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 can it acquire the right to transmit and transmit a frame to the station device. If the access point device determines that the wireless channel is busy through carrier sense during the backoff counter countdown, it stops counting down the backoff counter. Then, when the wireless channel becomes idle again, the access point device waits for the same period as the previous IFS, and then resumes counting down the remaining part of the previous backoff counter.

[0031] The receiving station, a station device, receives the frame, reads the PHY header of the frame, and demodulates the received frame. The station device can then determine whether the frame is addressed to itself by reading the MAC header of the demodulated signal. The station device can also determine the destination of the frame based on information contained in the PHY header (e.g., a group identification number (GID: Group ID) contained in VHT-SIG-A).

[0032] If a station device determines that a received frame is addressed to itself and demodulates the frame without error, it must transmit an Ack frame to the access point device, which is the transmitting station, indicating that the frame was received correctly. The Ack frame is one of the highest-priority frames that is transmitted after waiting only an SIFS period (without a random backoff time). The access point device terminates a series of communications upon receiving the Ack frame from the station device. If the station device fails to receive a frame correctly, it will not transmit an Ack frame. Therefore, if the access point device does not receive an Ack frame from the receiving station (station device) within a certain period (SIFS + Ack frame length) after transmitting the frame, it will determine that the communication has failed and terminate the communication. Thus, the end of a single 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 a beacon frame or other notification signal is transmitted or when fragmentation is used to divide the transmitted data.

[0033] When a station device determines that a received frame is not addressed to the station device, the station device sets a network allocation vector (NAV) based on the length of the frame included in the PHY header or the like. The station device does not attempt transmission during the period set in the NAV. In other words, the station device performs the same operation as when it determines that the wireless channel is busy by physical CS during the period set in the NAV. Therefore, communication control using NAV is also called virtual carrier sense (virtual CS). In addition to being set based on information included in the PHY header, the NAV is also set by RTS frames and CTS frames introduced to solve the hidden terminal problem.

[0034] Next, an example of the operation when an access point device transmits a signal to a station 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 (PC) controls the transmission right of each device within the BSS. Generally, an access point device becomes the PC and acquires the transmission right of the station device within the BSS.

[0035] 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 PC controls the transmission right during the CFP. The access point device, which is the PC, broadcasts a beacon frame including information such as the CFP duration (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 waiting for the CW. A station device that receives the beacon frame sets the CFP Max duration included in the beacon frame in its NAV. Thereafter, until the period set in the NAV elapses or a signal announcing the end of the CFP (e.g., a data frame including CF-end) is received within the BSS, the station device can acquire the transmission right only when it receives a signal signaling acquisition of the transmission right for the device from the PC (e.g., a data frame including CF-poll). During the CFP period, no packet collisions occur within the same BSS, so each station device does not take the random backoff time used in DCF.

[0036] The wireless communication device has either a function for transmitting a PPDU or a function for receiving a PPDU, or both. Fig. 2 is a diagram showing an example of the configuration of a PPDU transmitted by a wireless communication device. A PPDU conforming to the IEEE 802.11a / g standard is configured to include an L-STF, an L-LTF, an L-SIG, and a Data frame (MAC frame, payload, data section, data, information bits, etc.). A PPDU conforming to the IEEE 802.11n standard is configured to include an L-STF, an L-LTF, an L-SIG, an HT-SIG, an HT-STF, an HT-LTF, and a Data frame. A PPDU conforming to the IEEE 802.11ac standard is configured to include some or all of the following: L-STF, L-LTF, L-SIG, VHT-SIG-A, VHT-STF, VHT-LTF, VHT-SIG-B, and a Data frame. A PPDU conforming to the IEEE 802.11ax standard is configured to include some or all of the following: L-STF, L-LTF, L-SIG, RL-SIG, which is a time-repeated L-SIG, HE-SIG-A, HE-STF, HE-LTF, HE-SIG-B, and a Data frame. The PPDU being considered for the IEEE 802.11be standardization is a structure that includes some or all of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-SIG, EHT-STF, HET-LTF, and Data frames.

[0037] The L-STF, L-LTF, and L-SIG enclosed by dotted lines in Figure 2 are structures commonly used in the IEEE 802.11 standard (hereinafter, L-STF, L-LTF, and L-SIG are also collectively referred to as the L-header). For example, a wireless communication device compatible with the IEEE 802.11a / g standard can properly receive an L-header in a PPDU compatible with the IEEE 802.11n / ac / ax / be standard. A wireless communication device compatible with the IEEE 802.11a / g standard can receive a PPDU compatible with the IEEE 802.11n / ac / ax / be standard as a PPDU compatible with the IEEE 802.11a / g standard.

[0038] However, wireless communication devices that comply with the IEEE 802.11a / g standards cannot demodulate PPDUs that comply with the IEEE 802.11n / ac / ax / be standards that follow the L-header, and therefore cannot demodulate information related to the transmitter address (TA), receiver address (RA), duration / ID field, etc.

[0039] IEEE 802.11 specifies a method of inserting Duration information into L-SIG as a method for a wireless communication device conforming to the IEEE 802.11a / g standard to appropriately set NAV (or perform reception operation for a predetermined period of time). Information on the transmission rate in the L-SIG (RATE field, L-RATE field, L-RATE, L_DATARATE, L_DATARATE field) and information on the transmission period (LENGTH field, L-LENGTH field, L-LENGTH) are used by a wireless communication device conforming to the IEEE 802.11a / g standard to appropriately set NAV.

[0040] The wireless communication device can transmit the L-SIG multiple times (L-SIG Repetition). In this case, the receiving wireless communication device can improve the demodulation accuracy of the L-SIG by receiving the L-SIG transmitted multiple times using maximal ratio combining (MRC), for example. Furthermore, when the wireless communication device has correctly received the L-SIG using MRC, it can interpret the PPDU including the L-SIG as a PPDU that complies with the IEEE 802.11ax or IEEE 802.11be standard.

[0041] Even during a PPDU reception operation, the wireless communication device can perform a reception operation of a part of a PPDU other than the PPDU (for example, a preamble, L-STF, L-LTF, PHY header, etc., as defined by IEEE 802.11) (also referred to as a dual reception operation). When the wireless communication device detects a part of a PPDU other than the PPDU during a PPDU reception operation, the wireless communication device can update some or all of the information related to the destination address, source address, PPDU, or Data period.

[0042] Ack and BA can also be called responses (response frames). Also, probe responses, authentication responses, and connection responses can also be called responses.

[0043] Fig. 3 is a diagram showing an example of a sounding procedure for the purpose of channel estimation of a wireless communication path in IEEE 802.11ax. In the example shown in Fig. 3, an access point device (AP) first transmits a Null Data PPDU (NDP) Announcement frame 3001 that specifies information indicating a station device (STA) that will be the target of the upcoming sounding (the receiver of the sounding frame) and the type of feedback information. The access point device then transmits an NDP frame 3002 including a training field for channel estimation SIFS after the NDP Announcement frame. The station device performs channel estimation based on the received NDP frame 3002, and transmits a frame, such as a Compressed Beamforming / CQI frame 3003, that feeds back the channel estimation result to the access point device SIFS after the NDP frame 3002. [1. First Embodiment]

[0044] FIG. 4 is a diagram showing an example of a wireless communication system according to this embodiment. Wireless communication system 4003-1 includes wireless communication device 4001-1 and wireless communication devices 4002-1 to 4002-3. Wireless communication device 4001-1 is also referred to as access point device 4001-1, and wireless communication devices 4002-1 to 4002-3 are also referred to as station devices 4002-1 to 3. Wireless communication devices 4002-1 to 4002-3 (station devices 4002-1 to 4002-3) are also referred to as wireless communication device 4002A (station device 4002A) as devices connected to wireless communication device 4001-1. Wireless communication device 4001-1 and wireless communication device 4002A are wirelessly connected and are capable of transmitting and receiving PPDUs to and from each other. The wireless communication system according to this embodiment may also include wireless communication system 4003-2 in addition to wireless communication system 4003-1. Wireless communication system 4003-2 includes wireless communication device 4001-2 and wireless communication devices 4002-4 to 4002-6. Wireless communication device 4001-2 is also referred to as access point device 4001-2, and wireless communication devices 4002-4 to 4002-6 are also referred to as station devices 4002-4 to 4002-6. Wireless communication devices 4002-4 to 4002-6 (station devices 4002-4 to 4002-6) are also referred to as wireless communication device 4002B (station device 4002B) as devices connected to wireless communication device 4001-2. Furthermore, when wireless communication device 4001-1 and wireless communication device 4001-2 (access point devices 4001-1, 4001-6) are described without specifying each other, they are also referred to as wireless communication device 4001 (access point device 4001), and when wireless communication devices 4002-1 to 4002-6 (station devices 4002-1 to 4002-6) are described without specifying each other, they are also referred to as wireless communication device 4002 (station device 4002). Wireless communication system 4003-1 and wireless communication system 4003-2 form different BSSs, but this does not necessarily mean that the ESSs (Extended Service Sets) representing service sets forming LANs (Local Area Networks) are different.In other words, wireless communication devices belonging to the same ESS can be regarded as belonging to the same network from a higher layer. Furthermore, BSSs are connected via a DS (Distribution System) to form an ESS. Note that each of the wireless communication systems 4003-1 and 4003-2 can also include multiple wireless communication devices.

[0045] 5 is a diagram showing an example of the configuration of station device 4002. Station device 4002 includes a wireless control unit (wireless control step) 5001, a timer unit (timer step) 5002, a wireless communication unit (wireless communication step) 5003, and an antenna unit 5004. Furthermore, wireless communication unit 5003 includes a physical layer frame generation unit (physical layer frame generation step) 5003a, a wireless transmission unit (wireless transmission step) 5003b, a wireless reception unit (wireless reception step) 5003c, a received power measurement unit (received power measurement step) 5003d, a channel estimation unit (channel estimation step) 5003e, and a signal demodulation unit (signal demodulation step) 5003f.

[0046] The wireless control unit 5001 performs information processing on layers higher than the physical layer, such as the MAC layer and LLC layer, for information handled within the wireless communication device itself (such as information related to frames to be transmitted and MIB (Management Information Base)) and frames received from other wireless communication devices, and also controls the wireless communication unit 5003.

[0047] The timer unit 5002 includes one or more timers and manages the timers related to the sounding process. Details of the timer unit 5002 will be described later. Note that, in the example of Fig. 5, the timer unit 5002 is described as being included in the wireless control unit 5001, but is not limited to this configuration. The timer unit 5002 may be provided outside the wireless control unit 5001 and configured to operate under control from the wireless control unit 5001.

[0048] The physical layer frame generation unit 5003a has a function of generating a physical layer frame (PPDU). The physical layer frame generation unit 5003a performs error correction coding, modulation, beamforming processing (precoding processing), etc. on the MAC layer frame sent from the wireless control unit 5001. The beamforming processing may be realized by multiplying the modulated signal by a beamforming matrix (beamforming filter) notified by the wireless control unit 5001. The physical layer frame generation unit 5003a outputs the generated physical layer frame to the wireless transmission unit 5003b.

[0049] The wireless transmitting unit 5003b converts the physical layer frame input from the physical frame generating unit 5003a into a radio frequency (RF) band signal to generate a wireless signal. The processing performed by the wireless transmitting unit 5003b includes digital-to-analog conversion, filtering, frequency conversion from baseband frequency to wireless frequency, etc. The wireless transmitting unit 5003b transmits the generated wireless signal via the antenna unit 5004.

[0050] The wireless receiving unit 5003c has a function of converting a wireless signal received via the antenna unit 5004 into a baseband signal and generating a physical layer signal (for example, a physical layer frame). The processing performed by the wireless receiving unit 5003c includes frequency conversion processing from a wireless frequency to a baseband frequency, filtering, analog-to-digital conversion, etc. The physical layer signal, which is the received signal converted into a digital signal by the wireless receiving unit 5003c, is input to a received power measuring unit 5003d, a channel estimating unit 5003e, and a signal demodulating unit 5003f.

[0051] The received power measurement unit 5003d measures the received power of the received signal input from the wireless receiving unit 5003c. The received power measurement unit 5003d can measure the received power of the radio wave received on the frequency channel to be measured, the received power of the LTF of the received physical layer frame, etc. The received power measurement unit 5003d can notify the wireless control unit 5001 of the measurement result of the received power.

[0052] The channel estimation unit 5003e estimates the channel state through which the physical layer frame has propagated, based on the received signal of the LTF (L-LTF, HT-LTF, VHT-LTF, HE-LTF, etc.) included in the physical layer frame received by the wireless receiving unit 5003c. The channel estimation unit 5003e can notify the signal demodulation unit 5003f and the wireless control unit 5001 of the channel estimation result.

[0053] The signal demodulation unit 5003f performs channel equalization, demodulation, error correction decoding, etc. on the physical layer frame received by the wireless receiving unit 5003c, and acquires information such as the PHY header and MAC layer frame. The channel equalization process can use the channel estimation results of the channel estimator 5003e, etc. The signal demodulation unit 5003f outputs the acquired PHY header and MAC layer frame to the wireless control unit 5001.

[0054] The wireless control unit 5001 can perform physical carrier sensing and virtual carrier sensing based on the received power measurement results in the received power measuring unit 5003 d and information acquired in the signal demodulation unit 5003 f, and can determine the state of the wireless channel (including determining whether it is in an idle state or a busy state). The wireless control unit 5001 can notify the wireless communication unit 5003 of this wireless channel state determination information.

[0055] When there is control information, data, etc. to be transmitted, the wireless control unit 5001 can start a backoff procedure using the wireless channel state determination information. The wireless control unit 5001 generates a backoff counter based on the CW and has a countdown function for the backoff counter. For example, the wireless control unit 5001 can count down the backoff counter when the wireless channel state determination information indicates an idle state, and can stop the countdown of the backoff counter when the wireless channel state determination information indicates a busy state. Furthermore, the wireless control unit 5001 makes a transmission decision using either the wireless channel state determination information or the backoff counter value, or both. For example, the wireless control unit 5001 can notify the wireless communication unit 5003 of transmission decision information when the wireless channel state determination information indicates an idle state and the backoff counter value is 0. Furthermore, the wireless control unit 5001 can notify the wireless communication unit 5003 of transmission decision information when the wireless resource state determination information indicates an idle state.

[0056] FIG. 6 shows an example of the configuration of an access point device 4001. The access point device 4001 includes a wireless control unit (wireless control step) 6001, a wireless communication unit (wireless communication step) 5003, and an antenna unit 5004. Furthermore, the wireless communication unit 5003 includes a physical layer frame generation unit (physical layer frame generation step) 5003a, a wireless transmission unit (wireless transmission step) 5003b, a wireless reception unit (wireless reception step) 5003c, a received power measurement unit (received power measurement step) 5003d, a channel estimation unit (channel estimation step) 5003e, and a signal demodulation unit (signal demodulation step) 5003f. The access point device 4001 of FIG. 6 is basically configured similarly to the station device 4002 of FIG. 5. Therefore, the following description will focus on the differences between the two, and will omit a description of similar parts. Furthermore, parts corresponding to those in the station device of FIG. 5 will be described using the same reference numerals.

[0057] The wireless control unit 6001 processes information handled within the wireless communication device (such as information related to frames to be transmitted and MIB (Management Information Base)) and frames received from other wireless communication devices at layers higher than the physical layer, such as the MAC layer and LLC layer, and also controls the wireless communication unit 5003.

[0058] The physical layer frame generation unit 5003a has a function of generating a physical layer frame (PPDU). The physical layer frame generation unit 5003a performs error correction coding, modulation, beamforming processing (precoding processing), etc. on the MAC layer frame sent from the wireless control unit 6001. The beamforming processing may be realized by multiplying the modulated signal by a beamforming matrix (beamforming filter) notified by the wireless control unit 6001. The physical layer frame generation unit 5003a outputs the generated physical layer frame to the wireless transmission unit 5003b.

[0059] The received power measurement unit 5003d measures the received power of the received signal input from the wireless receiving unit 5003c. The received power measurement unit 5003d can measure the received power of the radio wave received on the frequency channel to be measured, the received power of the LTF (L-LTF, HT-LTF, VHT-LTF, HE-LTF, etc.) of the received physical layer frame, etc. The received power measurement unit 5003d can notify the wireless control unit 6001 of the measurement result of the received power.

[0060] The channel estimation unit 5003e estimates the channel state through which the physical layer frame has propagated, based on the LTF received signal included in the physical layer frame received by the wireless receiving unit 5003c. The channel estimation unit 5003e can notify the signal demodulation unit 5003f and the wireless control unit 6001 of the channel estimation result.

[0061] The signal demodulation unit 5003f performs channel equalization, demodulation, error correction decoding, etc. on the physical layer frame received by the wireless receiving unit 5003c, and acquires information such as the PHY header and MAC layer frame. The channel equalization process can use the channel estimation results of the channel estimator 5003e, etc. The signal demodulation unit 5003f outputs the acquired PHY header and MAC layer frame to the wireless control unit 6001.

[0062] When there is control information, data, a beacon, or the like to be transmitted, the wireless control unit 6001 can start a backoff procedure using the wireless channel state determination information. The wireless control unit 6001 generates a backoff counter based on the CW and has a countdown function for the backoff counter. For example, the wireless control unit 6001 can count down the backoff counter when the wireless channel state determination information indicates an idle state, and can stop the backoff counter countdown when the wireless channel state determination information indicates a busy state. Furthermore, the wireless control unit 6001 makes a transmission decision using either the wireless channel state determination information or the backoff counter value, or both. For example, the wireless control unit 6001 can notify the wireless communication unit 5003 of transmission decision information when the wireless channel state determination information indicates an idle state and the backoff counter value is 0. Furthermore, the wireless control unit 6001 can notify the wireless communication unit 5003 of transmission decision information when the wireless resource state determination information indicates an idle state.

[0063] A multi-link device (MLD) is a device capable of multi-link communication, and an access point device that supports MLD is referred to as an MLD access point device, and a station device that supports MLD is referred to as an MLD station device. Furthermore, MLD access point devices and MLD station devices are also collectively referred to as MLD wireless communication devices. In this embodiment, the wireless communication devices 1-1 and 1-2 described above are described as MLD wireless communication devices, but in actual operation, not all wireless communication devices in a wireless communication system may be MLD compatible.

[0064] The MLD access point device 20000-1 and the MLD station device 30000-1 will be described using Figure 7. The MLD wireless communication device is composed of multiple sub-wireless communication devices corresponding to the frequency bands (or channels, or sub-channels) of each link (also referred to as a physical layer link) that constitutes the multi-link. Figure 6 shows an example in which the MLD access point device 20000-1 is composed of three sub-wireless communication devices, in this case three sub-access point devices (20000-2, 200000-3, and 20000-4), but the number of sub-access point devices may be any number greater than or equal to two. Similarly, Figure 7 shows an example in which the MLD station device 30000-1 is composed of three sub-wireless communication devices, in this case three substation devices (30000-2, 300000-3, and 30000-4), but the number of substation devices may be any number greater than or equal to two. In addition, the sub-wireless communication device (sub-access point device, sub-station device, etc.) may be configured as part of the circuitry within the wireless communication device, and may be called a sub-wireless communication unit (sub-access point unit, sub-station unit).

[0065] 7, for the sake of explanation, multiple sub-wireless communication devices are shown as logically separate blocks (squares). Physically, they may be configured as a single wireless communication device. Alternatively, they may be configured as physically separate sub-wireless communication devices, in which case each sub-access point device transmits and receives necessary information via connections 9-1 and 9-2, and each substation device transmits and receives necessary information via connections 9-3 and 9-4. This embodiment mainly focuses on the former case, i.e., a case where the device is physically configured as a single wireless communication device (10000-1), and the configuration thereof will be described later.

[0066] The number of sub-access point devices included in one MLD access point device and the number of substation devices included in one MLD station device vary depending on the grade, class, and capabilities of each MLD wireless communication device. The higher the grade, class, and capabilities of an MLD wireless communication device, the greater the number of sub-wireless communication devices (sub-access point devices, substation devices) it may have. In other words, the number of sub-wireless communication devices (sub-access point devices, substation devices) owned by each MLD wireless communication device located within a wireless communication system varies depending on the grade, class, and capabilities, and the number of sub-wireless communication devices does not have to be the same.

[0067] The substation device 30000-2 connects (associates) with the sub-access point device 20000-2 and establishes link 1. The substation device 30000-3 connects (associates) with the sub-access point device 20000-3 and establishes link 2. The substation device 30000-4 connects (associates) with the sub-access point device 20000-4 and establishes link 3. In the description of this embodiment, the number of links constituting the multi-link is three, but this is not limited to this and any number may be used. The frequency used by each link can be set arbitrarily from the 2.4 GHz band, 5 GHz band, 6 GHz band, 60 GHz band, 140 GHz band, 300 GHz band, or any other frequency band, channel, or sub-channel supported by the wireless communication system, and may vary depending on the laws and regulations of each country.

[0068] Multi-link communication is also possible between MLD station devices. For example, in the example of Fig. 8, MLD station device 30001-1 is equipped with three substation devices (30001-2, 30001-3, 30001-4), and MLD station device 30002-1 is equipped with three substation devices (30002-2, 30002-3, 30002-4).

[0069] For example, let us consider an example of a robot equipped with station devices, in which multiple station devices cooperate to execute a single task. In this case, the multiple station devices must exchange information, such as each other's status and how to execute the task, at the same time and with high reliability. Therefore, each station device is capable of communicating via multilinks, efficiently exchanging information using multiple links. If multiple station devices simultaneously transmit frames over a single link during information exchange between the station devices, frame collisions occur, preventing correct demodulation. In this embodiment, to avoid frame collisions, a station device instructs the transmission timing of each station device. Assume that each station device has simultaneous transmission and reception (STR) capabilities over different links. A group of multiple station devices that cooperate to execute a single task is also referred to as a user group. Multiple user groups may exist in the same area (floor). Figure 9 shows an example in which user group 20-1 and user group 20-2 exist in the same area. User group 20-1 includes station devices 10-1, 10-2, 10-3, and 10-4. The user group 20-2 includes station devices 11-1, 11-2, and 11-3. The same station device may be included in different user groups.

[0070] Each station device measures the communication quality for each link and shares the measured data with the other station devices, thereby establishing a sub-user group for each link that allows communication between the station devices. A sub-user group is a part (subset) of a user group, but the sub-user group and the user group may be the same. Since it is desirable for the number of station devices (members) that can belong to a sub-user group to be the number that can exchange information within one TXOP period, an upper limit may be set, and this upper limit may be different for each link. Furthermore, the station list (member list) of the sub-user group for each link is shared within the user group. Figure 10 shows an example of subgroups 30-1 and 30-2 of user group 20-1. In the example of Figure 10, subgroup 30-1 includes station devices 10-1, 10-2, 10-3, and 10-4, and subgroup 30-2 includes station devices 10-2, 10-3, and 10-4. For example, in subgroup 30-1, communication occurs between station devices via link 1, and in subgroup 30-2, communication occurs between station devices via link 2.

[0071] Station devices (members) belonging to a user group attempt to acquire a TXOP on available links, and the station device that acquires the TXOP first becomes the coordinator (TXOP holder, Sharing STA). Since information exchange occurs between each station device at the same time, the user group must be the union of the sub-user groups of the links that acquire the TXOP at the same time. The coordinator transmits an RTS / CTS frame (also referred to as a first control frame) to the sub-user group of the link that acquires the TXOP, causing station devices other than the station devices belonging to the sub-user group to set their NAVs. This first control frame may include information indicating one sub-user group, multiple sub-user groups, or at least one user group. The coordinator determines the information exchange schedule (transmission and reception timing) for each station device, taking into account the sub-user group of the link that acquires the TXOP. Then, it transmits a trigger frame (also referred to as a second control frame) containing the information exchange schedule to each user. This trigger frame may be transmitted on both Link 1 and Link 2. A station device that receives a trigger frame on at least one of link 1 and link 2 transmits a data frame containing its own information at the transmission timing indicated by the information contained in the trigger frame on the link that received the trigger frame. The trigger frame includes, for example, the timing for each member of the sub-user group to transmit a data frame or the timing for receiving a data frame. The data frame includes a terminal ID (identifier), its own posture information, the communication quality between itself and each terminal device, and some or all of the surrounding observation information. The posture information includes its own orientation and information indicating whether the work can be continued (completed). If the work cannot be continued (completed), the work is suspended. The surrounding observation information includes information on obstacles such as people and objects in the vicinity.

[0072] Station devices other than the coordinator are also called shared station devices (Shared STAs). When a shared station device receives a first control frame from the coordinator, it transmits a CTS frame if it determines that the NAV has not been set by the wireless frames transmitted by the other station devices and that the shared station device is idle. When a shared station device receives a second control frame from the coordinator, it transmits a data frame at the transmission timing instructed by the second control frame and receives the data frame from the other station devices at the reception timing.

[0073] FIG. 11 shows an example of the transmission timing and reception timing of data frames transmitted over links 1 and 2. Link 1 corresponds to subgroup 30-1, and link 2 corresponds to subgroup 30-2. The table in FIG. 11 indicates whether each station device transmits or receives at timing 1 or timing 2. Note that in the figure, transmission is indicated by T and reception is indicated by R, but the present invention is not limited to this, and any distinction between transmission and reception is sufficient. Furthermore, to reduce the amount of information, only the transmission timing may be indicated. In the example of FIG. 11, station device 10-1 communicates over link 1 but not over link 2. Therefore, station device 10-2 can receive the data frame of station device 10-1 at timing 1 over link 1 and transmit a data frame containing information about station devices 10-1 and 10-2 at timing 2 over link 2.

[0074] As described above, the coordinator needs to acquire a TXOP for multiple links at the same time. Typically, a random backoff is set for each link, and a TXOP is acquired when the countdown reaches 0. Therefore, the probability of acquiring a TXOP for each link at the same time is low. Therefore, an example of a procedure for acquiring a TXOP for multiple links at the same time will be described. The first procedure involves setting different random backoffs for Link 1 and Link 2. If Link 1's countdown reaches 0 first, the coordinator waits until Link 2's countdown reaches 0. If Link 1 is idle when Link 2's countdown reaches 0, Link 1 and Link 2 can acquire a TXOP at the same time. The second procedure involves setting the same random backoff value for each link. As an example, considering fairness with other communication devices, the maximum value of the random backoff values ​​for each link is set as the random backoff value for each link. However, this is not limited to this. Other methods may be used to determine the random backoff value as long as fairness can be ensured to a certain extent. In this way, if Link 1 is idle during the random backoff period, the TXOP acquisition timing for each link can be synchronized. Although the first and second procedures described above have been explained using two links, link 1 and link 2, the present invention is not limited to this, and similar procedures can be applied to cases of three or more links.

[0075] The timing of acquiring TXOP between links does not necessarily have to be the same, as long as information can be exchanged between each station device during one TXOP period. Therefore, an allowable difference in the timing of acquiring TXOP may be set. For example, if a TXOP can be acquired within a timing difference D between links, the coordinator can be established. The value of D may be fixed or may vary.

[0076] The timing for transmitting or receiving a data frame can be a predetermined interval (e.g., Transmit Time Interval (TTI), slot, or subframe). The TTI length can be a fixed value (e.g., 1 ms) and can consist of a fixed number of TTIs during one TXOP period or after the second control frame transmission during a TXOP period. In this case, the timing shown in Figure 11 can be indicated by a TTI number.

[0077] The terminal device according to this embodiment does not necessarily need to set different frequencies for link 1 and link 2. For example, the terminal device according to this embodiment can set frequencies for link 1 and link 2 such that at least a portion of the communication band (frequency resources such as frequency bands, channels, and subchannels supported by the wireless communication system) is common. In this case, the terminal device according to this embodiment may have a function that enables simultaneous transmission and reception (STR) for different links, as described above, even at the same frequency. For link 1 and link 2, for which the same frequency is set, the terminal device can set subgroup 30-1 for link 1 and subgroup 30-2 for link 2, and perform communication. The TXOP for link 1 and link 2 is secured in the same manner as described above. However, when the STR function is used at the same frequency, a situation arises in which the interference between the links cannot be ignored. In this case, if the terminal device determines that the interfering signal received by the receiver of each link is a signal transmitted from another link of the terminal device, it can raise the carrier sense level to secure the transmission right. The method of determination is not limited to any particular one, but for example, it can be determined from the header information of the physical layer or MAC layer of the received signal, or it can be determined based on whether the control unit of the terminal device has instructed it to transmit another signal over another link, or it can be determined based on whether the terminal device has been instructed by another device to transmit a wireless signal over another link.

[0078] In a terminal device according to this embodiment, when the same frequency is set for multiple links (e.g., link 1 and link 2), a trigger frame that triggers a frame on each link can be transmitted via any one of the links. In this case, the terminal device can include information in the trigger frame indicating that a frame will be triggered on link 1 and link 2. For example, the terminal device can include both link IDs indicating link 1 and link 2 in the trigger frame, and can include information indicating the subgroup set for link 1 and the subgroup set for link 2 in the trigger frame, as well as information indicating the terminal devices included in each subgroup. Furthermore, the terminal device can arbitrarily select a link from link 1 or link 2 to transmit a trigger frame, or the link from which the trigger frame is transmitted can be set in advance, for example, by transmitting from the link with the smallest link ID.

[0079] Furthermore, the terminal device according to this embodiment does not necessarily need to be an MLD capable of setting multiple links. It is sufficient for the terminal device according to this embodiment to be capable of performing STR at the same frequency for one link or one frequency band supported by the wireless system. In this case, the terminal device according to this embodiment can simultaneously set subgroup 1 and subgroup 2 for one link. Alternatively, subgroup 1 and subgroup 2 may be simultaneously set using frequency division multiplexing technology such as OFDMA (Orthogonal Frequency Division Multiple Access).

[0080] Furthermore, the terminal device according to this embodiment can simultaneously set different beamformings for link 1 and link 2. In this case, the beamforming method is not limited to a specific one, but the following description will be given assuming the case of setting analog beamforming. The terminal device can set a first beamforming for link 1 and a second beamforming for link 2. It is preferable that the first beamforming and the second beamforming are formed so as not to interfere with each other in the terminal device receiving the signals. By performing this control, when subgroups 1 and 2 are set for link 1 and link 2, respectively, the terminal device according to this embodiment can simultaneously secure TXOPs for each subgroup and transmit frames. The above description has been given of an example in which the terminal device sets link 1 and link 2. However, link 1 and link 2 do not necessarily need to use the same frequency; at least a portion of the communication band may be set to a common frequency. Furthermore, the terminal device can simultaneously set first beamforming and second beamforming for one link.

[0081] In the method described above, it can be said that the terminal device according to this embodiment simultaneously configures the subgroups for link 1 and link 2 using spatial division multiplexing technology. The terminal device according to this embodiment can simultaneously configure beamforming for each link when the number of degrees of freedom for spatial multiplexing, determined by the number of antennas provided in the terminal device, is equal to or greater than the number of subgroups to be multiplexed. On the other hand, the terminal device according to this embodiment can simultaneously configure beamforming for each link under certain conditions even when the number of degrees of freedom for spatial multiplexing is less than the number of subgroups to be multiplexed. For example, if the number of degrees of freedom for spatial multiplexing is 2 and the number of subgroups to be multiplexed is 3, the terminal device will configure the same beamforming for at least two subgroups. However, if subgroup 1 and subgroup 2 for which the same beamforming is configured are spaced apart from the terminal device by different distances, the terminal devices belonging to each subgroup can reduce the interference power of signals addressed to other subgroups using interference suppression technology on the receiving side, allowing the terminal device according to this embodiment to simultaneously configure beamforming for more than two subgroups.

[0082] Furthermore, the terminal device according to this embodiment can be equipped with a plurality of radio access technologies (RATs). The terminal device can be equipped with a first RAT and a second RAT, and can set a first subgroup in the first RAT and a second subgroup in the second RAT. In this case, the radio access methods of the first RAT and the second RAT may differ. For example, a situation may be considered in which carrier sensing is required in the first RAT, while carrier sensing is not required in the second RAT. In this case, the terminal device according to this embodiment can start transmission in the second RAT at the timing when a transmission right is secured in the first RAT in which carrier sensing is required.

[0083] The above-mentioned TXOP may overlap with a service period for providing a specific service, such as an R-TWT service period (Restricted Target Wake Time Service Period, R-TWT SP). The service period, R-TWT service period, and TXOP are also referred to as transmission periods. R-TWT is a mechanism for media access protection and resource reservation for transmitting low-latency traffic. The R-TWT SP is a period negotiated using R-TWT setup. During the R-TWT SP, if a station device is an R-TWT member, it can transmit low-latency traffic preferentially. In R-TWT setup (R-TWT membership setup), to become an R-TWT member, a station device can request (Request TWT) addition to the access point device to which it is connected. If the Request TWT is approved by the access point device (Accept TWT), the station device can become an R-TWT member. If the request TWT is not approved by the access point device (reject TWT), the station device cannot become an R-TWT member.

[0084] FIG. 12 shows a transmission procedure within an R-TWT SP according to this embodiment. In the example of FIG. 12, a coordinator instructs (controls) frame transmission by each terminal device for an R-TWT service period divided into three periods, subperiod 1 to subperiod 3. Note that the coordinator can be an access point device or a station device, but here it will be described as an access point device. The coordinator transmits a trigger frame to each station device. The station device that receives the trigger frame transmits a data frame (Trigger Based (TB) PPDU) as a response. If the access point device receives the received data frame without error, it transmits a response frame such as an ACK or Block ACK (BA) to the station device. Note that one or more station devices that transmit data frames in subperiod 1 are also referred to as terminal group 1, one or more station devices that transmit data frames in subperiod 2 are also referred to as terminal group 2, and one or more station devices that transmit data frames in subperiod 3 are also referred to as terminal group 3. The trigger frame includes information indicating one or more station devices (e.g., identification information), a subperiod in which the station device transmits a data frame, resource units assigned to the station device, and some or all of the streams assigned to the station device. A station device that receives the trigger frame transmits a data frame in the resource units of the subperiod indicated in the trigger frame. The transmission of data frames in a subperiod uses frequency multiplexing (OFDMA), spatial multiplexing (MU-MIMO; Multi-User Multiple Input Multiple Output), and time multiplexing (TDMA; Time Division Multiple Access) for station devices belonging to a terminal group. The R-TWT SP is scheduled by a TWT element included in a beacon frame. The TWT element includes the start timing of the R-TWT SP, the start timing of one or more subperiods, and some or all of the information indicating the subperiod.The start timing of a subperiod is expressed as a difference (or offset) from the transmission timing of a beacon frame or a difference (or offset) from the start timing of an R-TWT SP. In this way, by collectively instructing station devices to transmit in multiple subperiods using a trigger frame, it becomes possible to efficiently use the R-TWT SP.

[0085] Note that the subperiods may be selected from predefined patterns. The predefined patterns may include the number of subperiods in the R-TWT SP, the communication direction in the subperiod (downlink, uplink, terminal-to-terminal communication, etc.), and the like. FIG. 13 shows an example of predefined patterns in the R-TWT SP. In pattern 1, two subperiods are set in the R-TWT SP. In pattern 2, three subperiods are set in the R-TWT SP. In pattern 3, three subperiods are set in the R-TWT SP, and the communication direction for each subperiod is also set. In pattern 3, the communication direction is limited to uplink in subperiod 1, uplink in subperiod 2, and downlink in subperiod 3. For example, in pattern 3, the coordinator can collect information from terminal group 1 in subperiod 1, collect information from terminal group 2 in subperiod 2, and issue instructions or provide information to terminal groups 1 and 2 in subperiod 3.

[0086] For example, if transmission in subperiod 1 fails (NACK), it is desirable to retransmit in subperiod 2. In this case, the coordinator can transmit information indicating a schedule change during or immediately after subperiod 1. The information indicating a schedule change includes information indicating one or more station devices (e.g., identification information), the subperiods in which the station devices will transmit data frames, the resource units to which the station devices are assigned, and some or all of the streams to which the station devices are assigned, for all subperiods from a certain subperiod onward.

[0087] Furthermore, the information indicating a schedule change may instruct a change or skip of only a specific sub-period, regardless of whether retransmission is to be performed. In this case, the information indicating a schedule change may include some or all of the following: information indicating a sub-period to be retransmitted, information indicating a change to a different allocation (schedule), and information indicating an invalidation of the sub-period settings. For example, when transmission by all station devices in sub-period 1 is not successful, the information indicating a sub-period to be retransmitted may include information indicating a retransmission of sub-period 1 in sub-period 2. If a station device receiving the information indicating a schedule change is not successful in transmission in sub-period 1, the station device transmits in sub-period 2 with the same settings as sub-period 1. The information indicating a change to a different allocation (schedule) may include the newly assigned station device, the resource units to be assigned to the station device, and some or all of the streams to be assigned to the station device. A station device receiving information indicating a change to a different transmission will not transmit a data frame if the previously received trigger frame does not include information identifying the station device, even if the previously received trigger frame included information identifying the station device itself. Furthermore, the information indicating an invalidation of the sub-period settings invalidates the information set in the previous trigger frame. A station device that receives information indicating that the sub-period setting is to be invalidated does not transmit a data frame even if information indicating the station device itself was included in a previously received trigger frame. Note that the coordinator can transmit information indicating the schedule change by including it in a response frame such as a BA frame.

[0088] A station device can request the access point device to set a subperiod. When requesting the setting of a subperiod, the station device can also include setting information in the request. The setting information includes the number of subperiods to be set, the communication direction of each subperiod, and some or all of the TIDs of each subperiod. If the access point device accepts the request from the station device, it transmits information indicating acceptance as a response. If the access point device does not accept the request, it transmits information indicating rejection to the station device. Note that when the access point device transmits information indicating acceptance, it may indicate acceptance of the setting of the subperiod together with the setting information, or it may accept the setting of the subperiod and not set the subperiod according to the setting information transmitted from the station device.

[0089] The R-TWT SP can also be set on multiple links (for example, link 1 and link 2). Furthermore, by aligning the R-TWT SP and subperiods across multiple links, the number of subperiods available per unit time increases, enabling more efficient communication. The coordinator can transmit a TWT element included in a beacon frame transmitted on link 1, including information indicating that the R-TWT SP is aligned with other links (by setting "Aligned"). The beacon frame and TWT element transmitted on link 1 are also referred to as the first beacon frame and first TWT element, respectively. The beacon frame and TWT element transmitted on link 2 are also referred to as the second beacon frame and second TWT element, respectively. The station device receives a first TWT element with Aligned set and a second TWT element with Aligned set, and if the start timing of the R-TWT SP set in the first TWT element and the second TWT element is the same or within a predetermined error (e.g., 1 time unit), it can determine that the R-TWT SPs of link 1 and link 2 are aligned. Figure 14 shows an example of communication between an MLD access point device acting as a coordinator and an MLD station device on link 1 and link 2. In the example of Figure 14, the start timing of the R-TWT SP and each subperiod is aligned on link 1 and link 2. The MLD access point device transmits a trigger frame indicating subperiod 1 to the MLD station device on link 1. It also transmits a trigger frame indicating subperiod 3 to the MLD station device on link 2. The MLD station device transmits data frames in the subperiods indicated in the trigger frames received on link 1 and link 2. The MLD station device can belong to a terminal group. For example, each link may belong to a different terminal group, or the links may belong to a common terminal group. In this way, by aligning the R-TWT SP and sub-periods for multiple links, the MLD station device can transmit in multiple sub-periods.Furthermore, if there are multiple links, even if there is no opportunity to transmit on one link (link 1), there is a possibility that there will be an opportunity to transmit on another link (e.g., link 2), which increases the possibility of transmitting necessary data within the R-TWT SP, enabling low-latency communication. In the above description, a trigger frame is transmitted for each link, but the present invention is not limited to this. It is also possible for one trigger frame to include information on multiple links. Furthermore, information indicating a schedule change transmitted on one link may include information on multiple links. Furthermore, a BA frame (response frame) transmitted on one link may include a BA (response frame) of another link or information indicating a schedule change.

[0090] A station device can request the access point device of one link to set sub-periods for multiple links. The station device can transmit, via one link, configuration information including information requesting the setting of sub-periods for multiple links. When sub-periods are set for multiple links, at least the number of sub-periods set for each link can be the same. Furthermore, the communication directions of each sub-period can be the same or different. The station device can request the access point device to align the communication directions of the sub-periods for each link. In this case, the station device includes, in the configuration information, information indicating that the communication directions for the multiple links are to be aligned.

[0091] The 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. The communication device according to the present invention can also be effective in, for example, a frequency band called a white band that is not actually used for purposes such as preventing interference between frequencies even though permission to use it for a specific service is granted by a country or region (for example, a frequency band allocated for television broadcasting but unused in some regions), 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, and then stored in various ROMs or HDDs. The information is then read, modified, and written by the CPU as needed. The recording medium for storing the program may be a semiconductor medium (e.g., a ROM, a non-volatile memory card, etc.), an optical recording medium (e.g., a DVD, an MO, an MD, a CD, a BD, etc.), a magnetic recording medium (e.g., a magnetic tape, a flexible disk, etc.), or the like. Furthermore, not only are the functions of the above-described embodiments implemented by executing the loaded program, but the functions of the present invention may also be implemented by processing in cooperation with an operating system or other application programs, etc., 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 is also included in the present invention. Furthermore, part or all of the communication device in the above-described embodiments may be realized as an LSI, which is typically an integrated circuit. Each functional block of the 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.

[0094] Furthermore, the method of integration is not limited to LSI, but 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-mobile 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 communication device and a communication method.

[0098] 10-1 to 10-4 Station devices 11-1 to 11-3 Station devices 20-1, 20-2, user groups 30-1, 30-2, sub-user groups 3001 NDP Announcement frame 3002 NDP frame 3003 Compressed Beamforming / CQI frame 4001-1, 4001-2 Wireless communication devices (access point devices) 4002-1 to 4002-6 Wireless communication devices (station devices) 4003-1, 4003-2 Wireless communication system 5001 Wireless control unit 5002 Timer unit 5003 Wireless communication unit 5003a Physical layer frame generation unit 5003b Wireless transmission unit 5003c Wireless reception unit 5003d Received power measurement unit 5003e Channel estimation unit 5003f Signal demodulation unit 5004 Antenna unit 6001 Wireless control unit 20000-1 MLD access point device 20000-2, 20000-3, 20000-4 Sub wireless communication device (sub-access point device) 30000-1 MLD station device 30000-2, 30000-3, 30000-4 Sub wireless communication device (substation device) 30001-1 MLD station device 30001-2, 30001-3, 30001-4 Sub wireless communication device (substation device) 30002-1 MLD station device 30002-2, 30002-3, 30002-4 Sub wireless communication device (substation device)

Claims

1. A communication device that communicates with one or more terminal devices, comprising: a control unit and a transmission unit, wherein the control unit sets one or more user groups including one or more terminal devices among the plurality of terminal devices, sets one or more sub-user groups for the user group, each of the sub-user groups being a subset of any of the one or more user groups, sets a transmission period at once for some or all of the sub-user groups, and the transmission unit transmits a control frame and a data frame within the transmission period, the control frame including the transmission timing of the data frame in each of the terminal devices included in at least any of the sub-user groups, the transmission timing being one of a plurality of timings set within the transmission period, and the transmission period being either a TXOP or a service period. A communication device.

2. Further comprising a reception unit, wherein the control frame includes timing information for receiving the data frame, and the reception unit receives the control frame and the data frame of each of the user groups within the transmission period based on the timing information. The communication device according to claim 1.

3. The data frame includes information indicating whether it is feasible, and when information indicating infeasibility is received, information indicating interruption of the operation is notified. The communication device according to claim 2.

4. The reception unit receives information indicating a request to set a plurality of timings within the transmission period from the terminal device. The communication device according to claim 2.

5. Communicates with the terminal device in multi-link, and aligns the transmission period and a plurality of timings within the transmission period in at least two links constituting the multi-link. The communication device according to claim 1.

6. The terminal device set in the sub-user group is a terminal device permitted to communicate within the transmission period. The communication device according to any one of claims 1 or 5.

7. A communication method in a communication device that communicates with one or more terminal devices, comprising a control step and a transmission step, wherein the control step sets one or more user groups including one or more terminal devices among the plurality of terminal devices, sets one or more sub-user groups for the user group, each of the sub-user groups being a subset of any of the one or more user groups, sets a transmission period at once for some or all of the sub-user groups, and the transmission step transmits a control frame and a data frame within the transmission period, the control frame including the transmission timing of the data frame in each of the terminal devices included in at least any of the sub-user groups, the transmission timing being one of a plurality of timings set within the transmission period, and the transmission period being either a TXOP or a service period.

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