Access point, terminal, and communication method

Abstract

This access point is provided with: a control circuit that controls a relay operation for at least one of a first terminal, which performs uplink transmission, and a second terminal, which relays the uplink transmission; and a reception circuit that receives a signal of the uplink transmission in accordance with the relay operation control.

Description

Access point, terminal, and communication method

[0001] The present disclosure relates to an access point, a terminal, and a communication method.

[0002] The Institute of Electrical and Electronics Engineers (IEEE) is currently developing specifications for a successor standard to IEEE 802.11be (hereinafter referred to as "11be"), a standard of 802.11. This successor standard may also be referred to as "Ultra High Reliability (UHR)."

[0003] IEEE 802.11-22 / 1919r1, Considerations on UHR PARIEEE 802.11-23 / 0042r0, Thought for Range Extension in UHRIEEE P802.11be / D3.0, January 2023IEEE Std 802.11ax-2021

[0004] However, the method for controlling signal transmission in wireless communication such as wireless LAN has not been fully studied.

[0005] Non-limiting embodiments of the present disclosure contribute to providing an access point, a terminal, and a communication method that can improve the efficiency of transmission control in wireless communication.

[0006] An access point according to one embodiment of the present disclosure includes a control circuit that controls relay operations for at least one of a first terminal that performs uplink transmission and a second terminal that relays the uplink transmission, and a receiving circuit that receives the uplink transmission signal in accordance with the control of the relay operation.

[0007] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

[0008] According to an embodiment of the present disclosure, for example, it is possible to improve the efficiency of transmission control in wireless communication.

[0009] Further advantages and benefits of one embodiment of the present disclosure will become apparent from the specification and drawings. Such advantages and / or benefits may be provided by some embodiments and features described in the specification and drawings, respectively, but not necessarily all of them may be provided to obtain one or more identical features.

[0010] Diagram showing an example of Downlink (DL) transmission operation using RelayDiagram showing an example of the format of Triggered Transmission Opportunity (TXOP) Sharing Mode included in the Multi User (MU) - Request to Send (RTS) Trigger frameBlock diagram showing an example of the configuration of a portion of a Station (STA)Block diagram showing an example of the configuration of a portion of an Access Point (AP)Block diagram showing an example of the configuration of an STABlock diagram showing an example of the configuration of an APDiagram showing an example of Relay operationDiagram showing an example of Relay operationDiagram showing an example of Relay operationDiagram showing an example of Relay operationDiagram showing an example of Relay operationDiagram showing an example of Relay operationDiagram showing an example of Relay operationDiagram showing an example of Trigger Dependent User Info formatDiagram showing an example of the format of an MU-RTS TXS Trigger frameDiagram showing an example of the formats of Special User Info and User InfoDiagram showing an example of the format of User InfoDiagram showing an example of the format of a Relay Control elementDiagram showing an example of a Relay operationDiagram showing an example of a Relay Control elementDiagram showing an example of a Relay operationDiagram showing an example of a Relay operationDiagram showing an example of a Relay Control element formatDiagram showing an example of a Relay operationDiagram showing an example of a Relay operationDiagram showing an example of a Trigger frame formatUser FIG. 1 shows an example of the format of User Info. FIG. 1 shows an example of a Relay operation. FIG. 1 shows an example of a Relay Control element format. FIG. 1 shows an example of a Relay operation. FIG. 1 shows an example of a Relay operation. FIG. 1 shows an example of a Relay operation. FIG. 1 shows an example of a Relay operation. FIG. 1 shows an example of a Relay operation. FIG. 1 shows an example of a Relay operation. FIG. 1 shows an example of a Relay operation. FIG. 1 shows an example of a Relay operation.

[0011] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0012] Low latency is required for UHR, and use in factories or warehouses, for example, is being considered as a use case for UHR (see, for example, Non-Patent Document 1).

[0013] In factories or warehouses, which are one use case for UHR, there may be many areas where radio waves cannot reach due to obstructions caused by devices or shelves. Furthermore, in factories or warehouses, there may be a lot of noise (interference waves), which may narrow the reach of radio waves. One method for expanding the communication range is to apply a relay (e.g., relay control).

[0014] As an example of a downlink (DL) transmission method using relay, the application of Triggered Transmission Opportunity (TXOP) sharing shown in Fig. 1 has been proposed (see, for example, Non-Patent Document 2). Note that Triggered TXOP sharing is specified by, for example, the "Triggered TXOP sharing Mode subfield" in the Common Info field of the Multi User (MU) - Request to Send (RTS) Trigger frame shown in Fig. 2 (see, for example, Non-Patent Document 3).

[0015] For example, Non-Patent Document 2 shows an example of an operation performed via an STA (hereinafter referred to as a "relay STA") that relays DL transmission from an access point (e.g., also called a "base station"; hereinafter referred to as an "AP (Access Point)") to a terminal (e.g., also called a Station (STA) or a non-AP STA; hereinafter referred to as an "STA").

[0016] Non-Patent Document 2 discloses relaying of DL transmissions from an AP to a STA, but does not consider a method for relaying uplink (UL) transmissions from a STA to an AP.

[0017] In a non-limiting example embodiment of the present disclosure, a method for improving the efficiency of relay transmission in UL transmission is described.

[0018] [Configuration of Wireless Communication System] A wireless communication system according to an embodiment of the present disclosure may include, for example, at least one AP 200 and a plurality of STAs 100 (or may include APs). For example, the STAs 100 and the AP 200 perform relay communication or control relay communication.

[0019] 3 is a block diagram illustrating a configuration example of a portion of the STA 100 according to an embodiment of the present disclosure. In the STA 100 illustrated in FIG. 3, a control unit (e.g., corresponding to a control circuit) controls a relay operation for another terminal (a relay destination STA described later) that performs uplink transmission based on control information from the AP 200. A transmission unit (e.g., corresponding to a transmission circuit) transmits (e.g., forwards) an uplink transmission signal from the other terminal to the AP 200.

[0020] 4 is a block diagram illustrating a configuration example of a portion of an AP 200 according to an embodiment of the present disclosure. The AP 200 illustrated in FIG. 4 controls relay operations for at least one of a first terminal (e.g., a destination STA described later) that performs uplink transmission and a second terminal (e.g., a relay STA described later) that relays the uplink transmission. A receiver (e.g., a receiver circuit) receives an uplink transmission signal.

[0021] [Configuration Example of STA 100] FIG. 5 is a block diagram showing a configuration example of the STA 100. As shown in FIG.

[0022] The STA 100 shown in FIG. 5 may include, for example, a radio transmission / reception unit 101, a received packet decoding unit 102, a relay control unit 103, a control signal generation unit 104, and a transmission packet generation unit 105.

[0023] At least one of the received packet decoding unit 102, the relay control unit 103, the control signal generating unit 104, and the transmitted packet generating unit 105 shown in FIG. 5 may be included in the control unit shown in FIG. 3, and the wireless transmitting / receiving unit 101 shown in FIG. 5 may be included in the transmitting unit shown in FIG. 3.

[0024] Furthermore, the STA 100 may be either a relaying STA (hereinafter referred to as a "relay STA") or a relay destination STA (hereinafter referred to as a "relay destination STA"). In this case, both the relay STA and the relay destination STA may have the configuration shown in Fig. 5. Furthermore, for example, the relay destination STA may have a configuration that does not include the Relay control unit 103 among the configurations shown in Fig. 5.

[0025] 5, a wireless transmission / reception unit 101 receives a wireless signal via an antenna and performs wireless reception processing on the received signal. The wireless transmission / reception unit 101 outputs the received signal (received packet) after wireless reception processing to a received packet decoding unit 102 and a relay control unit 103. The wireless transmission / reception unit 101 also performs wireless transmission processing on a transmission packet input from a transmission packet generation unit 105, and transmits the signal after wireless transmission processing (e.g., a wireless signal) via the antenna.

[0026] The received packet decoding unit 102, for example, decodes a received packet input from the wireless transmission / reception unit 101, outputs the decoded data (e.g., output data), and outputs the decoded control information to the relay control unit 103 and the control signal generation unit 104.

[0027] The relay control unit 103 controls the relay operation based on the received packet input from the wireless transmitting / receiving unit 101 and the control information input from the received packet decoding unit 102. An example of the relay control in the relay control unit 103 will be described later. The relay control unit 103 outputs information related to relay control (for example, referred to as "relay control information") to the control signal generation unit 104 and the transmission packet generation unit 105.

[0028] The control signal generating unit 104 generates a control signal based on, for example, input data, control information input from the received packet decoding unit 102, relay control information input from the relay control unit 103, and at least one of the internal states of the STA 100, and outputs the control signal to the transmitted packet generating unit 105.

[0029] The transmission packet generation unit 105 generates a transmission packet based on at least one of the input data, the relay control information input from the relay control unit 103, and the control signal input from the control signal generation unit 104, and outputs the generated transmission packet to the wireless transmission / reception unit 101.

[0030] [Configuration Example of AP 200] Fig. 6 is a block diagram showing a configuration example of the AP 200. The AP 200 may have a configuration in which a scheduler 201 is added to the configuration of the STA 100 shown in Fig. 5, for example.

[0031] At least one of the scheduling unit 201, the received packet decoding unit 102, the relay control unit 103, the control signal generating unit 104, and the transmitted packet generating unit 105 shown in FIG. 6 may be included in the control unit shown in FIG. 4, and the wireless transmitting / receiving unit 101 shown in FIG. 6 may be included in the receiving unit shown in FIG. 4.

[0032] 6 , a scheduler 201 performs scheduling for the STA 100 based on, for example, at least one of input data, control information input from the received packet decoder 102, and the internal state of the AP 200. The scheduler 201 outputs, for example, information relating to control of transmission packet generation by the transmission packet generator 105 and information relating to relay control in the relay controller 103 to the relay controller 103 and the control signal generator 104.

[0033] The above describes exemplary configurations of the STA 100 and the AP 200.

[0034] As an example, the STA 100 can be a relay communication apparatus (e.g., also referred to as a relay STA or a relay device). Another STA 100 can be a communication terminal (e.g., also referred to as a relay destination STA) that communicates with the AP 200 via the relay communication apparatus. The AP 200 can be an "AP communication apparatus" that communicates with the communication terminal via the relay communication apparatus.

[0035] In another example, the AP 200 may be a relay communication device. The STA 100 may be a communication terminal that communicates with another AP 200 via a relay communication device. The other AP 200 may be an AP communication device that communicates with a communication terminal via a relay device. Here, the AP communication device and the AP 200 that is a relay communication device may form (or join) a group of APs (also referred to as, for example, an AP cooperation group, a seamless roaming AP group, a mobility domain, a Single Mobility Domain AP Multi-Link Device (SMD AP MLD), a Mesh group, etc.) by, for example, executing a setup procedure. The APs 200 that belong to the group of APs may share information about the STA 100 with each other. In addition, the information regarding STA100 may include, for example, information regarding association (Association ID (AID)), information regarding security (e.g., status information or context information, etc.), information regarding traffic (transmitted and received data) (e.g., Traffic Identifier (TID), buffer status, etc.), or measurement information at STA100 (e.g., signal strength / quality between the serving AP and neighboring APs, etc.).

[0036] In another example, a relay communication device may be configured to have both the functionality of the STA 100 (e.g., FIG. 5 ) and the functionality of the AP 200 (e.g., FIG. 6 ). The functionality of the STA 100 provided by the relay communication device is called a “logical STA,” and the functionality of the AP 200 provided by the relay communication device is called a “logical AP.” For example, a logical STA may communicate with another AP 200 (e.g., an AP communication device), and the logical AP may communicate with another STA 100 (e.g., a communication terminal), thereby realizing relay communication between the AP communication device and the communication terminal. The logical AP may form (or join) an AP group with other APs. Furthermore, the relay communication device may be provided with, for example, a relay control function. The relay control function, for example, exchanges transmission / reception data and control information for relaying between the functionality of the STA 100 (logical STA) and the functionality of the AP 200 (logical AP). For example, the relay control function may be part of a Medium Access Control (MAC) function. Alternatively, the relay control function may connect to the logical STA and the logical AP via a MAC Service Access Point (SAP) to exchange data, and may connect to the logical STA and the logical AP via a MAC sublayer Management Entity (MLME) SAP to exchange control information. This relay control function may also be called a higher layer (e.g., a higher layer or an upper layer) or a Station Management Entity (SME).

[0037] Furthermore, communication between a communication device and a communication terminal via a relay communication device may be referred to as “relay communication.” Furthermore, the relay communication device may be configured to perform relay communication but not to perform communication different from relay communication, or may be configured to switch between communication with the AP communication device and at least one of other STAs and relay communication, or may be configured to perform multiplexed communication with communication with the AP communication device and at least one of other STAs and relay communication.

[0038] Below, examples of relay communication by the STA 100 and the AP 200 and methods of relay communication control (for example, methods 1 to 10) will be described.

[0039] In the following description, an example of relay communication between an AP 200 (e.g., referred to as AP) and two STAs 100 (e.g., referred to as STA1 and STA2) will be described. For example, STA1 is a "relay STA" and STA2 is a "relay destination STA," and STA1 relays UL communication between STA2 and the AP.

[0040] (Method 1) FIG. 7 shows an example of relay communication according to Method 1.

[0041] In Figure 7, STA1 (relay STA) and STA2 (relay destination STA) associate (or connect) to the AP, and in response to a Relay instruction from the AP, STA1 (relay STA) relays (or forwards, transmits) UL data from STA2 (relay destination STA) to the AP.

[0042] In addition, in relay operation, as an identifier for identifying an STA (e.g., a relay STA and a relay destination STA), if the relay destination STA is associated with the source AP of the Relay instruction, an AID may be assigned by the source AP, and if the relay destination STA is not associated with the source AP of the Relay instruction, an identifier for identifying a non-associated STA (e.g., an Unassociated STA Identifier (USID)) may be assigned.

[0043] Furthermore, for example, if the destination STA is associated with an AP different from the source AP of the Relay instruction, an AID may be assigned to the destination STA by the AP with which the destination STA is associated.

[0044] An example of a case where a relay STA is associated with an AP different from the source AP is when a relay STA has the functions of STA 100 and AP 200 and the relay STA is associated with the relay STA. In this case, the relay STA, in the role of AP 200, may assign an AID to the relay STA associated with the relay STA.

[0045] In this way, when an AID is assigned as an identifier for the relay STA by an AP other than the source AP (including, for example, a relay STA (e.g., having the role of AP200)), the AP other than the source AP may negotiate with the source AP and assign an AID to the relay STA that does not overlap with that of other STA100.

[0046] In addition, when a relay operation involves STA100 under multiple AP200, in addition to the AID, an identifier indicating the AP200 to which the STA is associated or the Basic Service Set (BSS) to which the STA100 belongs (e.g., BSSID or BSS Color) may be used in combination to identify the STA.

[0047] Furthermore, an identifier for identifying a relay STA may be assigned in the same manner as for a destination STA. For example, if a relay STA is associated with the source AP of the Relay instruction, the source AP may assign an AID to the relay STA, and if the relay STA is not associated with the source AP of the Relay instruction, the source AP may assign a USID to the relay STA. Also, if a relay STA is associated with an AP different from the source AP of the Relay instruction, the AP to which the relay STA is associated may assign an AID to the relay STA. Alternatively, an ID for identifying a relay STA may be defined separately from the AID.

[0048] 7 is a frame (or control information) transmitted to request (or solicit or urge) a destination STA to transmit data. The relay instruction frame may be, for example, a trigger frame or a new control frame (e.g., called a "relay control frame"). Instead of the relay instruction, at least one of the AP and the relay STA may use a frame that requests the destination STA to transmit data based on the Reverse Direction Protocol.

[0049] If the Relay instruction frame is a Trigger frame, for example, a "Relay Trigger frame" may be defined and used as a relay control variant of the Trigger frame, or an existing Trigger frame (for example, a Basic Trigger frame or an MU-RTS Trigger frame) may be used, or a frame that is an extension of an existing Trigger frame may be used.

[0050] In FIG. 7, the AP transmits a Relay instruction (control information) regarding a relay operation to at least one of STA1 (relay STA) and STA2 (relay destination STA).

[0051] When STA1 (relay STA) receives a Relay instruction sent by the AP, it may forward the Relay instruction to STA2 (relay destination STA). Note that, although Fig. 7 shows an example of operation in which STA1 forwards the Relay instruction to STA2, the AP may also directly send the Relay instruction to STA2. In this case, STA1 does not need to forward the Relay instruction.

[0052] When STA2 (destination STA) receives a Relay instruction from the relay STA or AP, it transmits UL data (Data) addressed to the AP. Note that, if STA2 does not hold UL data, it may transmit a QoS Null frame as a UL response.

[0053] When STA1 (relay STA) receives UL data from STA2, it transmits a response signal (for example, Ack) to STA2. In addition, STA1 transfers (or relays) the UL data from STA2 to the AP.

[0054] When the AP receives the UL data from STA1, it transmits a response signal (for example, Ack) to STA1.

[0055] In this way, the AP controls the relay operation of the destination STA that performs UL transmission and the relay STA that relays the UL transmission. For example, the AP may transmit a Relay instruction regarding the relay operation to the relay STA and the destination STA, and the relay STA may forward the Relay instruction to the destination STA. Then, based on the Relay instruction transmitted by the AP, the destination STA transmits UL data addressed to the AP, and the relay STA relays the UL data, thereby enabling UL transmission using Relay.

[0056] 7, the Relay instruction may include information regarding a section in which data or control information related to Relay can be transmitted (e.g., a TXOP section, hereinafter referred to as a "Relay transmission section"). The AP may wait for reception from a relay STA during the Relay transmission section, or may permit data transmission after receiving data from the relay STA during the Relay transmission section, or may control whether or not to transmit data depending on the type of data received from the relay STA. Furthermore, if the AP, which is a TXOP holder, does not detect a signal for a specified time after transmitting the Relay instruction, it may regain the transmission right and transmit to another STA. The specified time may be, for example, a period longer than a Short Interframe Space (SIFS) (e.g., PIFS or DIFS).

[0057] Also, for example, all IFSs within a sequence after receiving a Relay instruction (for example, within a Relay transmission section) may be set to SIFS.

[0058] Furthermore, STA1 (relay STA) may store data received from STA2 (relay destination STA) and, for example, if transfer to the AP fails, may separately retransmit the data to the AP.

[0059] <Regarding Encryption and Decryption> In addition, in the example of the relay operation shown in Fig. 7, the following encryption and decryption may be applied to transmission data (data) transmitted from STA2 (relay destination STA) to the AP via STA1 (relay STA). For example, the encryption or decryption process for a UL transmission signal may differ depending on whether the relay operation is performed or not.

[0060] For example, the information used for encryption by the destination STA (sender) (e.g., the value of the Address field included in the MAC header information) may be replaced from the MAC header value of the actual transmitted frame with "MAC header information used when the relay STA transmits a frame to the AP." This allows the AP (receiver) to decrypt the encrypted data.

[0061] Alternatively, instead of replacing the information used for encryption by the destination STA, the AP may change the information used for decrypting encrypted data. For example, the destination STA encrypts data using the MAC header of the actual transmitted frame. The AP may replace the MAC header information (e.g., the value of the Address field) used for decrypting encrypted data from the MAC header of the actual received frame with "MAC header information used when the destination STA transmits a frame to the relay STA."

[0062] Alternatively, instead of replacing the information used for encryption by the destination STA, the operation of the relay STA may be changed. For example, the destination STA sets the MAC header information (e.g., the value of the Address field) to "MAC header information used when the destination STA transmits a frame to the AP." The relay STA may transfer data in which the sender address is the destination STA and the receiver address is the AP in the Address field of the MAC header during the Relay transmission interval specified by the Relay instruction.

[0063] Also, for example, instead of replacing the information used for encryption by the destination STA, the relay STA may transmit encapsulated data. For example, the relay STA may construct a frame to be sent directly to the AP, and encapsulate the entire frame received from the destination STA (e.g., a signal including a header) in the payload of a Data frame. The AP may recognize that the received data in the Relay transmission section specified by the Relay instruction is a relay frame, and may decode the frame extracted from the payload by treating it as a "frame sent directly from the source (STA)."

[0064] The encryption and decryption of transmission data has been described above.

[0065] Although the case where transmission data is transmitted from a destination STA to an AP via a relay STA (for example, UL communication) has been described, the present invention is not limited to this, and the above-described relay communication may also be applied to, for example, a case where transmission data is transmitted from an AP to a destination STA via a relay STA (for example, DL communication). In this case, the above-described "destination STA" may be replaced with "AP", and "AP" may be replaced with "destination STA".

[0066] 7 illustrates a case where a relay STA transmits an Ack immediately after receiving data from a destination STA, but the present invention is not limited to this. For example, the relay STA may transmit an Ack to the destination STA after receiving an Ack from the AP. This allows the destination STA to determine that the AP has successfully received the data by receiving an Ack from the relay STA.

[0067] In addition, in the example of the relay operation shown in Fig. 7, data transmitted from a destination STA to an AP via a relay STA may be controlled as follows: For example, the transmission control of UL transmission may be different depending on whether the relay operation is performed or not.

[0068] For example, the destination STA may set (or limit) the amount of data to be transmitted in the relay operation to the amount of data that can be transferred within the relay transmission interval specified by the relay instruction from the AP.

[0069] Also, for example, in the Relay transmission interval, the relay STA may transfer data from the relay destination STA if data transfer is possible, and may not transfer data if data transfer is not possible.

[0070] Also, for example, the relay STA may transfer data that can be transferred (e.g., part of the data in the Aggregate-MAC Service Data Unit (A-MSDU)) within the Relay transmission section, and may not transfer data that cannot be transferred.

[0071] This allows data to be transferred within the relay transmission section during relay operation. Also, by transferring data within the relay transmission section, the time from transmission by the destination STA to reception by the AP can be shortened, enabling transmission with low latency.

[0072] The AP may specify whether or not to transfer data within the relay transmission section by using a relay instruction (or a relay control element, which will be described later), or may specify the type of data (e.g., access category (AC) or TID) to be transmitted by the relay destination STA. This enables the AP to control the data to be transmitted by the relay, such as by giving priority to data that requires low-latency transmission.

[0073] In the example of relay operation shown in FIG. 7 , if a relay STA (STA1) does not transfer data during a relay transmission interval, the relay STA may notify the AP of the reception status (e.g., reception success or reception failure) from the relay destination STA (STA2) to the relay STA. Note that a reception failure may include a transmission failure by the relay destination STA (e.g., when transmission is not possible due to carrier sense). Furthermore, the relay STA may determine that a transmission failure by the relay destination STA has occurred if it does not receive a signal from the relay destination STA after a specified time (e.g., SIFS interval) has elapsed since transmitting a relay instruction to the relay destination STA.

[0074] As a method for notifying the reception state, for example, a "Relay State frame" may be defined, and the relay STA may transmit the Relay State frame to the AP. Alternatively, instead of the Relay State frame, the relay STA may transmit at least one of an Ack and an NDP.

[0075] For example, as shown in Fig. 8, if a relay STA (STA1) does not detect a signal from a relay destination STA (STA2) for a period longer than SIFS (e.g., PIFS or DIFS) after transmitting a Relay instruction to the relay destination STA, the relay STA may determine that the reception status is a failure and transmit an NDP to the AP. The AP may determine that the reception status is a failure if it receives an NDP after transmitting the Relay instruction.

[0076] Also, for example, as shown in FIG. 9 , after transmitting a Relay instruction to a destination STA (STA2), if a relay STA (STA1) receives data from the destination STA at an SIFS interval (or an interval shorter than PIFS or DIFS), the relay STA (STA1) may transmit an Ack indicating "reception status = success" to the AP, in addition to the Ack addressed to the destination STA. The AP may determine that "reception status = success" when it receives an Ack after transmitting a Relay instruction. Note that the relay STA does not need to transmit an Ack addressed to the AP. In this case, the AP may receive an Ack sent by the relay STA to the destination STA and determine that "reception status = success." For example, by not transmitting an Ack addressed to the AP shown in FIG. 9 , Ack transmissions can be reduced, thereby improving throughput.

[0077] In this way, when no data transfer is performed in the Relay transmission section, the relay STA notifies the AP of the reception state, and the AP may control subsequent operations as follows.

[0078] For example, if it determines that the reception status is "successful," the AP may issue a transmission request (or a transfer request) to the relay STA. In response to the transmission request from the AP, the relay STA may transmit data (Data) from the relay destination STA shown in FIG. 9 to the AP. Also, if it determines that the reception status is "failed," the AP may retransmit a Relay instruction to the relay source STA (for example, the operation shown in FIG. 7). This eliminates the need for data transmission from the relay source STA to the relay STA when the reception status is "successful," thereby improving throughput.

[0079] Also, for example, after receiving an Ack or NDP from a relay STA, the AP may transmit to other STAs, etc., if possible, within the Relay transmission interval, thereby improving throughput.

[0080] If the destination STA does not have UL data, the destination STA may transmit a QoS Null frame as a UL response, which prevents the STA from responding because it has no data to transmit.

[0081] In addition, in the example of relay operation shown in Fig. 7, an operation in which the relay STA (STA1) transmits an Ack in response to data transmission from the destination STA (STA2) has been described, but this is not limiting. For example, as shown in Fig. 10, the relay STA may not transmit an Ack. In this case, the destination STA may determine that the relay STA has successfully received the data if the relay STA transmits data (data to be forwarded to the AP) after a specified time has elapsed (e.g., after an SIFS interval) after transmitting the data. Note that the destination STA may determine that the relay STA has successfully received the data if the data transmitted by the relay STA is the same as the data transmitted by the destination STA, or if an Ack or NDP is transmitted to the AP.

[0082] Furthermore, whether or not the relay STA needs to transmit an Ack may be determined (or instructed) by the AP or the relay STA, or may be defined in specifications. For example, the AP may notify (or control) whether or not the relay STA needs to transmit an Ack (e.g., whether or not the relay STA transmits a response signal to UL data from the relay STA) by a Relay instruction, or the relay STA may determine whether or not the relay STA needs to transmit an Ack based on the type of the relay destination STA (e.g., whether or not the relay operation of Method 1 is supported (e.g., a legacy terminal)).

[0083] This reduces the number of Ack transmissions and improves throughput.

[0084] (Method 2) In Method 2, a case where the Relay instruction shown in the operational example of Method 1 is included in the "MU-RTS Trigger frame" will be described.

[0085] FIG. 11 shows an example of operation when a Relay instruction is included in the MU-RTS Trigger frame.

[0086] In Figure 11, the AP may include control information regarding the relay operation (e.g., a relay instruction) in the MU-RTS Trigger frame (referred to as MU-RTS) that it sends to the relay STA (STA1), such as a relay operation specification, the ID of the relay STA (STA1), and the ID of the relay destination STA (STA2).

[0087] For example, as an example of specifying a relay operation, the relay operation may be defined using Reserved (for example, value = 3) in the Triggered TXOP sharing Mode subfield of the Common Info field in the MU-RTS Trigger frame shown in Figure 2.

[0088] Furthermore, as the ID of the relay STA, for example, the AID of the relay STA may be specified by AID12 of User Info in the MU-RTS Trigger frame.

[0089] Furthermore, as the ID of the destination STA, for example, the ID of the destination STA (e.g., AID) may be specified by Reserved or Trigger Dependent User Info of User Info in the MU-RTS Trigger frame. The AID of the destination STA may be defined as "Dest AID (or Destination AID)." The ID of the destination STA may also be specified by multiple pieces of User Info.

[0090] 11, STA1 (relay STA) transmits a Clear to Send (CTS) to the AP in response to the MU-RTS Trigger frame from the AP. STA1 may transmit the CTS to the AP, for example, by including it in a non-HT or non-HT duplicate PHY Protocol Data Unit (PPDU).

[0091] Furthermore, after transmitting the CTS, STA1 may transfer an MU-RTS Trigger frame to STA2 (relay destination STA).

[0092] The relay STA may change part of the MU-RTS Trigger frame to be transferred to the destination STA from the MU-RTS Trigger frame received from the AP. For example, the relay STA may change the value of the TXOP Sharing Mode subfield from 3 to 1 or 2, change AID12 in the User Info to Dest AID, or delete the Dest AID or Trigger Dependent User Info in the User Info. This allows the format of the MU-RTS Trigger frame to be sent to the destination STA to be set to the same format as the existing MU-RTS Trigger format, allowing the destination STA to perform existing STA operations.

[0093] Furthermore, the relay STA may forward the User Info in the MU-RTS Trigger frame received from the AP to the destination STA as is, or may change part of it (e.g., AID12 in the User Info) before forwarding it. As a result, if AID12 in the User Info is the AID of the destination STA, the destination STA can recognize that it is the destination STA and may perform an operation unique to the destination STA (e.g., replacing the information used for encryption as shown in Method 1, or performing an operation that does not require the relay STA to send an Ack). By changing AID12 in the User Info to the AID of the destination STA, the destination STA can determine that the trigger is addressed to the destination STA based on AID12 in the User Info, and can determine that the STA is the destination STA if Dest AID in the User Info is the AID of the destination STA.

[0094] Furthermore, when a relay STA directly forwards User Info in the MU-RTS Trigger frame received from the AP, the AID of the relay STA may be notified to the relay destination STA in advance. In this case, the relay destination STA may continue the decoding process if AID12 in User Info is the relay STA notified in advance.

[0095] 11, STA2 (destination STA) transmits a CTS to STA1 (relay STA) in response to the MU-RTS Trigger frame from STA1. STA2 may transmit a CTS to the relay STA, for example, by including it in a non-HT or non-HT duplicate PPDU. After transmitting the CTS, STA2 may transmit, for example, UL data.

[0096] In the subsequent operations in FIG. 11, for example, transmission and reception of data, Ack, and NDP shown in Method 1 may be performed.

[0097] In this way, by including a Relay instruction in the MU-RTS Trigger frame, the existing operation of CTS transmission is performed, so that it is possible to reduce the influence of interference due to transmission from hidden terminals, for example.

[0098] In the relay operation using the MU-RTS Trigger frame shown in FIG. 11 , as shown in FIG. 12 , the AP may transmit a CTS (e.g., “CTS-to-self”) before transmitting the MU-RTS Trigger frame (e.g., immediately before transmission). When an existing STA receives a CTS-to-self, it prohibits transmission within the TXOP period. In contrast, when a relay STA receives a CTS-to-self, for example, if it determines that the STA is a relay STA based on the MU-RTS Trigger frame received within the TXOP period, it may permit transmission within the TXOP period using CTS-to-self. In this case, to determine whether a relay STA is a relay STA, the relay STA may, for example, set the MU-RTS Trigger frame to be transmitted to the relay STA to have the TXOP Sharing Mode subfield set to 3 and the Dest AID not specified. In other words, the relay STA can determine that the STA is a relay STA when the TXOP Sharing Mode subfield set to 3 and the Dest AID not specified. This makes it possible to perform relay operation even when the AP transmits CTS-to-self.

[0099] <Format Example> An example of the format in Method 2 will be described.

[0100] For example, the MU-RTS TXS Trigger frame format (see, for example, Non-Patent Document 3) may be applied to the MU-RTS Trigger frame transmitted from the AP to the relay STA. Fig. 13 shows an example of a format that specifies a Dest AID (for example, the AID of a relay destination STA) in Trigger Dependent User Info included in User Info in the MU-RTS TXS Trigger frame.

[0101] Also, for example, Dest AID may be specified by a plurality of pieces of User Info instead of the format example shown in Fig. 13. For example, as shown in Fig. 14, in addition to Special User Info, a plurality of pieces of User Info (two in the example of Fig. 14) may be used, and the AID of the relay STA and the AID of the relay destination STA may be specified by AID12 in each piece of User Info.

[0102] Alternatively, for example, as shown in Fig. 15, the Dest AID may be specified in "U-SIG Disregard And Validate" of Special User Info, and the AID of the relay STA may be specified in AID12 in the subsequent User Info. Note that since it is expected that the U-SIG may be received by STAs other than the communication partner (including, for example, overlapped BSS (OBSS) STAs), it is not preferable to divert the U-SIG Disregard And Validate to other uses. However, since the CTS in response to the MU-RTS is transmitted in a non-HT or non-HT duplicate PPDU that does not include a U-SIG, the U-SIG Disregard And Validate may be diverted for relay control.

[0103] Furthermore, for example, the AP may notify the relay STA and the destination STA in advance of an ID (e.g., "Dest Short ID" (e.g., 6 bits)) corresponding to the Dest AID. In this case, instead of the format example shown in FIG. 13 , the Dest Short ID may be specified by at least a part of the Reserved field of User Info (6 bits in FIG. 16 ), as shown in FIG. 16 . For example, the Dest Short ID may be associated with an AID of a STA that can be a candidate for the destination STA (a candidate for the Dest AID), among the values ​​that can be used as the AID. Note that a new element (e.g., a "Relay Control element") may be used to notify the Dest AID and Dest Short ID. FIG. 17 shows an example format of the Relay Control element. For example, as shown in FIG. 17 , Element ID=255 and Element ID Extension=114 may be set in the Relay Control element, and the ID notification in the Relay Control element may be set to Type=0. Furthermore, multiple sets of Dest AID and Dest Short ID may be notified by the Relay Control element.

[0104] Alternatively, instead of the format example shown in FIG. 13 , the AP may assign an AID (hereinafter referred to as a "Relay AID") indicating the combination of a relay STA and a destination STA in advance, and the Relay AID may be notified to the relay STA and the destination STA by the Relay Control element. FIG. 18 shows an example format of a Relay Control element notifying the Relay AID, the AID of the relay STA (hereinafter referred to as a "Relay Point AID"), and the AID of the destination STA (Dest AID). In this case, the Relay AID may be specified in AID12 of User Info in the MU-RTS TXS Trigger frame transmitted to the relay STA and the destination STA. The relay STA continues decoding not only when AID12 in User Info is the AID of the STA but also when it is the Relay AID. If AID12 in User Info is the Relay AID, the relay STA can recognize that the STA is a relay STA based on the Relay Control element. The destination STA continues decoding not only when AID12 in User Info is the AID of the STA but also when it is the Relay AID. If AID12 in User Info is a Relay AID, the destination STA can recognize that the STA is the destination STA based on the Relay Control element.

[0105] Although the above example describes the case where the MU-RTS TXS Trigger frame format is used, a format other than the MU-RTS TXS Trigger frame format may also be applied. For example, the format of MU-RTS (e.g., a trigger with "Triggered TXOP sharing Mode subfield=0" shown in FIG. 2) may also be applied.

[0106] <Method of notifying a Relay Control element> Next, an example of an operation in which an AP notifies a Relay Control element in advance in the above-mentioned format example will be described. Note that, for example, a new frame or a Beacon may be used to notify the Relay Control element. Furthermore, when a new frame is used, for example, the Relay Control element may be notified in the Relay setup phase, and either the Relay operation of Method 1 or Method 2 may be performed in the Relay transmission phase.

[0107] FIG. 19 shows an example of operation using a new frame (for example, referred to as a "Relay Control frame"). The Relay Control frame may include a Relay Control element. The AP notifies a relay STA (STA1) of the Relay Control frame. For example, upon receiving the Relay Control frame from the AP, the relay STA transmits an Ack to the AP.

[0108] 19 , an operation example in which a relay STA returns a response to an AP (for example, a case in which a "Relay Control Request Frame" and a "Relay Control Response Frame" are used) may also be used. FIG. 20 shows an operation example of the Relay setup phase in which a relay STA returns a response to an AP. In FIG. 20 , for example, the Relay Control element (Type=0) shown in FIG. 17 or 18 may be notified in the Relay Control Request Frame, and the Relay Control element (Type=1) shown in FIG. 21 may be notified in the Relay Control Response Frame. In the Relay Control element shown in FIG. 21 , the relay STA may notify the AP of information indicating that transmission and reception with the relay destination STA is possible (for example, Dest Enable Flag=1) when transmission and reception with the relay destination STA is possible, and may notify the AP of information indicating that transmission and reception with the relay destination STA is impossible (for example, Dest Enable Flag=0) when transmission and reception with the relay destination STA is impossible. In this way, the AP may perform the Relay transmission phase for the STAs with Dest Enable Flag=1.

[0109] Instead of the Dest Enable Flag, for example, the path loss between the relay STA and the destination STA may be notified. If transmission and reception between the relay STA and the destination STA is not possible, the path loss may be set to the maximum value. In this case, the AP may execute a relay transmission phase in which the STA with the smallest path loss (excluding the maximum value) is set as the relay STA. This allows the AP to select the optimal relay STA.

[0110] Furthermore, in the case where the relay STA is configured or in a state where it uses information included in the Relay Control element instead of the Relay setup phase shown in Fig. 20, the relay STA may transfer a Relay Control element (Type = 0) to the relay STA, for example, as shown in Fig. 22. In this case, if the relay STA does not receive an Ack from the relay STA, it may transmit to the AP a Relay Control Response Frame including a Relay Control element (e.g., Fig. 21) with Dest Enable Flag = 0. Furthermore, for example, if communication between the relay STA and the relay STA is impossible, the relay STA may transmit to the AP a Relay Control Response Frame with Dest Enable Flag = 0 without transferring a Relay Control element (Type = 0) to the relay STA.

[0111] Here, an example of the operation of the Relay setup phase using a new frame has been described, but instead of a new frame, a Relay Control element may be included in a Beacon, as shown in Fig. 23. In order to identify a relay STA by a Beacon (broadcast transmission), for example, the Relay Control element shown in Fig. 17 may include the AID (Relay Point ID) of the relay STA. Fig. 24 shows an example format in which a Relay Point ID is added to the Relay Control element shown in Fig. 17.

[0112] (Method 3) Method 3 describes a case where, in the relay operation described in Method 2, the MU-RTS Trigger frame transferred from the relay STA to the relay destination STA is another frame (for example, a Basic Trigger frame).

[0113] The frame transferred from the relay STA to the destination STA is not limited to a Basic Trigger, and may be, for example, a frame for requesting the destination STA to transmit a frame addressed to the relay STA. The frame for requesting the destination STA to transmit a frame addressed to the relay STA may be, for example, a frame including information requesting the destination STA to transmit a frame based on the Reverse Direction Protocol, or may be a new control frame (for example, a P2P transmission grant frame).

[0114] FIG. 25 shows an example of an operation for changing an MU-RTS Trigger frame to a Basic Trigger frame.

[0115] In FIG. 25, the operations from when STA1 (relay STA) receives an MU-RTS Trigger frame from the AP until it transmits a CTS in response may be the same as those in method 2, for example.

[0116] After transmitting the CTS, STA1 (relay STA) transmits a Basic Trigger frame to STA2 (relay destination STA). Fig. 26 shows an example format of the Basic Trigger frame, and Fig. 27 shows an example format of User Info included in the Basic Trigger frame (see, for example, Non-Patent Document 4).

[0117] For example, to set the destination of a Basic Trigger frame sent by STA1 to STA2, the MAC address or broadcast address of the destination STA (STA2) may be set in the RA field (field indicating the destination) shown in Figure 26, and the AID of the destination STA may be set in the AID12 field in the User Info shown in Figure 27.

[0118] Note that a field (e.g., called a "Relay Flag") indicating whether or not the Basic Trigger frame is to be transmitted from a relay STA to a destination STA may be defined in the Reserved field in the Basic Trigger frame (e.g., Reserved field shown in Fig. 27). For example, Relay Flag = 1 may be set if the Basic Trigger frame is to be transmitted from a relay STA to a destination STA, and Relay Flag = 0 may be set if the Basic Trigger frame is not to be transmitted from a relay STA to a destination STA.

[0119] In Fig. 25, STA2 (destination STA) does not transmit a CTS when it receives a Basic Trigger frame from STA1 (relay STA). Furthermore, if the Relay Flag included in the Basic Trigger frame is set to 1, STA2 may transmit a UL response by permitting transmission in the TXOP section specified by the CTS transmitted by STA1 to the AP in response to the MU-RTS from the AP. For example, if STA2 has UL data to transmit stored in a buffer, it may transmit a data frame (Data) as the UL response.

[0120] When STA1 receives a UL response (e.g., a data frame), it may send an Ack to STA2 and forward the data frame to the AP. The AP may receive the data frame forwarded from STA1 and send an Ack to STA1.

[0121] In this way, by adding a flag indicating that the Basic Trigger frame is to be transmitted to the destination STA from the relay STA, the destination STA can transmit a UL response.

[0122] (Method 4) Method 4 describes a case where, in the relay operation described in Method 3, the MU-RTS Trigger frame transmitted from the AP to the relay STA is a Basic Trigger frame.

[0123] FIG. 28 shows an example of operation when the MU-RTS Trigger frame is changed to the Basic Trigger frame.

[0124] In the operation example shown in Fig. 28, the AP transmits a Basic Trigger frame to STA1 (relay STA) as a trigger for specifying a Relay operation. In the Basic Trigger frame transmitted by the AP to the relay STA, for example, in the format shown in Fig. 26, the address of STA1 (relay STA) may be set in the RA field, and the AID of STA2 (relay destination STA) may be set in AID12 in User Info.

[0125] 28, when STA1 receives a Basic Trigger frame from the AP, it does not transmit a CTS. Furthermore, when the address of STA1 is specified in the RA field in the Basic Trigger frame and an AID different from both the AID of STA1 and the AID corresponding to Special User Info is specified in AID12 in User Info, STA1 may determine that STA1 is a relay STA and that a relay destination STA is specified by AID12 in User Info.

[0126] The subsequent operations may be the same as those in Method 3, for example, and the setting of the Relay Flag described in Method 3 may not be performed.

[0127] This allows relay operation even when the destination STA is a terminal that does not perform an operation corresponding to a relay instruction (for example, a legacy terminal).

[0128] Note that the determination (or identification) of a relay STA may be limited to, for example, the case where the Basic Trigger frame contains only one User Info. Alternatively, the determination (or identification) of a relay STA may be limited to the case where AID12 in the User Info matches the AID of the destination STA notified by the Relay Control element described in Method 2. In this case, the Relay Control element may have a format including only the AID of the destination STA (Dest AID), as shown in FIG. 29 .

[0129] Furthermore, the User Info of the Basic Trigger frame transmitted by the AP may have the configuration of Special User Info described in Method 2. This makes it possible to identify that the Basic Trigger frame is a trigger that instructs a relay STA to perform a relay operation.

[0130] In addition, we have described a case where AID12 in User Info is set as the AID of the destination STA in the Basic Trigger frame sent by the AP, but this is not limited to this, and instead of the AID of the destination STA, for example, the Relay AID described in Method 2 may be set.

[0131] (Method 5) In Method 2, an example of operation was described in which the AP sends an MU-RTS Trigger frame to the relay STA as a Relay instruction, and the relay STA forwards the MU-RTS Trigger to the destination STA. However, if the destination STA directly receives the MU-RTS Trigger sent from the AP, there is no need to forward the MU-RTS Trigger frame from the relay STA to the destination STA.

[0132] Examples of cases in which the destination STA directly receives the MU-RTS Trigger transmitted from the AP include cases where the AP's transmission power is greater than the STA's transmission power, and the destination STA is able to receive signals directly from the AP in DL but is unable to transmit signals directly to the AP in UL, or cases in which the destination STA is able to send and receive signals with the AP in both DL and UL, but applies a relay to transmit UL data using a higher Modulation and Coding Scheme (MCS).

[0133] In this case, the relay STA may determine whether or not to forward the MU-RTS Trigger frame depending on whether the destination STA receives the MU-RTS Trigger frame transmitted from the AP. For example, if the destination STA does not receive a Relay instruction from the AP, the Relay instruction may be forwarded from the relay STA to the destination STA, and if the destination STA receives a Relay instruction from the AP, the Relay instruction may not be forwarded from the relay STA to the destination STA.

[0134] Figure 30 shows an example of operation when the destination STA receives an MU-RTS Trigger frame transmitted from the AP, and Figure 31 shows an example of operation when the destination STA does not receive an MU-RTS Trigger frame transmitted from the AP.

[0135] In FIGS. 30 and 31, the AP may transmit an MU-RTS Trigger frame to both STA1 (relay STA) and STA2 (relay destination STA) that allows the relay STA and the relay destination STA to be recognized.

[0136] For example, as shown in Figures 30 and 31, the AP may notify STA1 and STA2 in advance of information regarding the relay STA and the relay destination STA, as described in Method 2. As an example, the AP may notify STA1 and STA2 of the Relay Control element shown in Figure 24 according to the method shown in Figure 22, or may notify STA1 and STA2 of the Relay Control element in the format of Figure 24 with the Dest Short ID removed.

[0137] After notifying the Relay Control element, the AP transmits an MU-RTS Trigger frame to instruct the relay operation. As in Method 2, the MU-RTS Trigger frame may have a format in which the AID of the relay STA is set in AID12 in User Info, and the AID of the relay destination STA (Dest AID) is added.

[0138] STA1 (relay STA) may determine that it is a relay STA if AID12 in User Info in the MU-RTS Trigger frame received from the AP specifies STA1's AID and the STA1 receives an MU-RTS Trigger frame instructing relay operation.

[0139] If AID12 in User Info in the received MU-RTS Trigger frame is the AID of STA1 (relay STA), STA2 (relay STA) may continue decoding the received MU-RTS Trigger frame, and if the Dest AID specified by the received MU-RTS Trigger frame is the AID of STA2, STA2 may determine that STA2 is the relay STA.

[0140] For example, as shown in FIG. 30, when both STA1 (relay STA) and STA2 (destination STA) receive an MU-RTS Trigger frame from the AP, both STA1 and STA2 may transmit a CTS after SIFS. STA2 may then transmit UL data after SIFS from the CTS transmission, for example, as described in Method 1. Furthermore, when STA1 receives UL data after SIFS from the CTS transmission, it may determine that the destination STA has received an MU-RTS Trigger from the AP, and may not forward the MU-RTS Trigger frame to the destination STA. STA1 may then forward UL data to the AP, for example, in the same manner as in Method 1.

[0141] 31 , if STA1 (relay STA) receives an MU-RTS Trigger frame from the AP and STA2 (destination STA) does not receive the MU-RTS Trigger frame from the AP, STA1 may transmit a CTS after a SIFS. If STA1 does not detect a signal for a period longer than the period when the destination STA starts data transmission after transmitting a CTS (for example, a period longer than a SIFS (e.g., PIFS or DIFS)), STA1 may determine that the destination STA did not receive an MU-RTS Trigger from the AP and may transfer the MU-RTS Trigger frame to STA2 in the same manner as in Method 2 or Method 3. Thereafter, STA1 and STA2 may transmit, receive, and transfer data in the same manner as in Method 1.

[0142] In this way, by attempting to detect a signal over a PIFS or DIFS, the relay STA can detect whether the destination STA has started data transmission, and the relay STA transfers a trigger to the destination STA if the destination STA has not started data transmission, and does not transfer a trigger to the destination STA if the destination STA has started data transmission. This prevents unnecessary trigger transfers and improves throughput.

[0143] Although the format in which AID12 in User Info of the MU-RTS Trigger frame transmitted by the AP specifies a relay STA has been described above, the present invention is not limited thereto, and a format in which a relay destination STA is specified in AID12 in User Info and the AID of the relay STA is added instead of the Dest AID may also be used. In this case, when a relay STA receives an MU-RTS Trigger frame in which AID12 in User Info specifies the AID of the relay destination STA, the relay STA may continue decoding, and when the ID of the relay STA specified by the MU-RTS Trigger frame is the ID of the relay STA, the relay destination STA may determine the STA as a relay STA. Furthermore, when AID12 in User Info is the AID of the STA and the MU-RTS Trigger frame instructs a relay operation, the relay destination STA may determine the STA as a relay destination STA. Furthermore, the relay destination STA may perform existing operations when receiving an MU-RTS Trigger frame, for example, without determining (or identifying) the relay destination STA. This allows relay operation even when the destination STA is a terminal that does not perform operations in accordance with the relay instruction (for example, a legacy terminal).

[0144] In addition, although an example of operation has been described in which a relay STA or a relay destination STA is specified by AID12 in the User Info of the MU-RTS Trigger frame transmitted by the AP, the AP may notify the Relay Control element shown in Figure 18 in advance and notify the Relay ID by AID12 in the User Info of the MU-RTS Trigger frame.

[0145] (Method 6) Method 6 describes a case where, in the relay operation described in Method 5, the MU-RTS Trigger frame transmitted from the AP to the relay STA and from the relay STA to the relay destination STA is a Basic Trigger frame.

[0146] 32 and 33 show an example of operation when the MU-RTS Trigger frame is changed to the Basic Trigger frame.

[0147] In FIGS. 32 and 33, the AP may transmit a Basic Trigger frame to both STA1 (relay STA) and STA2 (relay destination STA) that allows the relay STA and the relay destination STA to recognize each other.

[0148] 32 and 33, the AP may notify STA1 and STA2 in advance of information regarding the relay STA and the relay destination STA, as described in Method 2. As an example, the AP may notify STA1 and STA2 of a Relay Control element including the Relay AID shown in FIG. 18 according to the method shown in FIG. 22.

[0149] After notifying the Relay Control element, the AP transmits a Basic Trigger frame instructing the relay operation. The Basic Trigger frame may have a format in which, for example, a broadcast address is set in the RA field and a Relay ID is set in AID12 in User Info.

[0150] STA1 (relay STA) may determine that it is a relay STA if AID12 in User Info of the Basic Trigger frame received from the AP specifies a Relay ID where the AID of STA1 is the Relay Point AID indicated in the Relay Control element.

[0151] STA2 (relay destination STA) may determine that STA2 is the relay destination STA if AID12 in the User Info of the received Basic Trigger frame specifies a Relay ID where the AID of STA2 is the Dest AID indicated in the Relay Control element.

[0152] For example, as shown in Fig. 32, when both STA1 (relay STA) and STA2 (relay destination STA) receive a Basic Trigger frame from the AP, both STA1 and STA2 may transmit and receive data SIFS after receiving the Basic Trigger frame, as described in Method 1. When the relay STA receives data SIFS after receiving the Basic Trigger, it determines that the relay destination STA has received a Basic Trigger from the AP, and does not need to forward the Basic Trigger frame to the relay destination STA. STA1 may then forward data to the AP in the same manner as in Method 1, for example.

[0153] Furthermore, for example, as shown in FIG. 33 , when STA1 (relay STA) receives a Basic Trigger frame from the AP and STA2 (relay destination STA) does not receive the Basic Trigger frame from the AP, if STA1 does not detect a signal for a period longer than the period for which the relay destination STA starts data transmission when it receives the Basic Trigger frame after receiving the Basic Trigger frame (for example, a period longer than SIFS (for example, PIFS or DIFS)), STA1 may determine that the relay destination STA has not received a Basic Trigger from the AP and may transfer the Basic Trigger frame to STA2 in the same manner as in Method 4. Thereafter, STA1 and STA2 may transmit, receive, and transfer data in the same manner as in Method 1.

[0154] In this way, the relay STA attempts to detect a signal over the PIFS or DIFS, thereby detecting whether the destination STA has started data transmission. The relay STA then transfers a trigger if the destination STA has not started data transmission, and does not transfer a trigger to the destination STA if the destination STA has started data transmission. This prevents unnecessary transfers and improves throughput.

[0155] Although the format in which the Relay AID is specified in AID12 in User Info of the Basic Trigger frame transmitted by the AP has been described, the present invention is not limited thereto, and a format in which the AID of a destination STA is set in AID12 in User Info may also be used. In this case, if AID12 in User Info of the received Basic Trigger frame specifies a Dest AID (the AID of the destination STA) whose AID is the Relay Point AID indicated in the Relay Control element, the relay STA may determine the STA as a relay STA, and if AID12 in User Info specifies the AID of the STA, the relay STA may determine the STA as a destination STA. Furthermore, the destination STA may perform existing operations when receiving a Basic Trigger frame, for example, without recognizing itself as a destination STA. In this case, a format in which the Relay ID is deleted from the Relay Control element may be applied, and the Relay Control element may be notified to the relay STA but not to the destination STA. In this way, by specifying the AID of the destination STA using AID12 in User Info, relay operation becomes possible even if the destination STA is a terminal (e.g., a legacy terminal) that does not perform operations in accordance with the relay instruction.

[0156] (Method 7) In the relay operation described in Methods 1 to 6, the AP may simultaneously issue transmission and reception instructions (for example, trigger transmissions shown in Methods 2 to 6) to multiple STAs (including STAs that do not perform relay operation). In this case, trigger transfer by relay operation and UL transmission from other STAs may be performed simultaneously, which may result in interference effects.

[0157] For example, in Method 7, the transmission frequency band of the trigger (e.g., Relay instruction) transferred by the relay STA to the destination STA may be different from the transmission frequency band of the UL transmission signal by another STA, thereby preventing interference caused by the trigger transfer in the relay operation.

[0158] For example, Figure 34 shows an example of operation in which, in addition to the relay operation using the Basic Trigger frame described in Methods 4 and 6, the Basic Trigger transmitted by the AP includes an UL transmission instruction to another STA (e.g., STA1).

[0159] 34, the AP transmits a Basic Trigger frame including User Info instructing UL data transmission to STA1 in addition to the Relay instruction described in Methods 4 and 6 when STA2 is the relay STA and STA3 is the destination STA. At this time, the transmission frequency band of the UL data designated for the destination STA (STA3) and the transmission frequency band of the UL data designated for STA1 may be set to different frequency bands.

[0160] In this case, STA2 (relay STA) may transfer the Basic Trigger to STA3 within the transmission frequency band of the UL data of the relay STA, which is specified by the Basic Trigger frame transmitted from the AP. That is, the transmission frequency band of the Basic Trigger frame transferred from the relay STA may be set within the transmission frequency band of the UL data of the relay STA.

[0161] In this way, by setting the frequency band for transferring the Basic Trigger frame to the transmission frequency band of the relay destination STA, the frequency band for transferring the Basic Trigger frame and the transmission frequency band of STA1 can be set to different frequency bands, thereby suppressing the impact of interference on STA1's UL data due to the transfer of the Basic Trigger.

[0162] In addition, in Fig. 34, the transmission frequency band of UL data for the destination STA specified by the Basic Trigger frame transmitted by the AP may be set (or limited) to a frequency band including the primary CH of the destination STA. For example, the AP may specify the primary CH of the destination STA to the relay STA and the destination STA in advance by the Relay Control element shown in Fig. 35. The primary CH specified by the Relay Control element may be the primary CH switched within the TXOP range specified by the Relay instruction. This allows the destination STA to perform signal detection operation for the primary CH for the transferred Basic Trigger frame, as with existing methods.

[0163] Furthermore, the transmission frequency band of UL data to the destination STA may be allocated in units of 20 MHz, together with the allocation of the preamble. By allocating the transmission frequency band of UL data in units of 20 MHz in this way, the frequency band of the preamble included in the UL transmission data of another STA (STA1 in FIG. 34 ) can be made different from the frequency band of the preamble included in the transferred Basic Trigger frame, thereby suppressing the influence of interference.

[0164] In Fig. 35, Type=1 indicates a Relay Control element that specifies a primary CH, Relay AID indicates the Relay AID notified by the Relay Control element (Type=0), and Channel Number indicates the number of the primary CH of the destination STA. In Fig. 35, an example is shown in which a primary CH is specified by the Relay Control element (Type=1), but a format in which a Channel Number is added to the Relay Control element (Type=0) may also be applied.

[0165] Also, while FIG. 34 shows the UL transmission procedure described in Method 4 as an example, the UL transmission procedure may be any of Methods 1 to 3 and Methods 5 to 7.

[0166] (Method 8) In Method 8, a method of applying collection and transmission of Buffer Status Reports (BSRs) to the relay operations described in Methods 1 to 7 will be described.

[0167] For example, as shown in Fig. 36, the AP transmits a frame (e.g., BSR Poll (BSRP)) requesting a BSR from STA2 (a relay destination STA). The BSRP may include destinations for multiple other STAs (e.g., STAs that do not perform relay operations (STAs not shown in Fig. 36)).

[0168] STA1 (relay STA) receives a frame (e.g., BSRP) from the AP and transmits a frame (e.g., BSRP with at least STA2 as the destination) notifying STA2 that a BSR is requested from the AP. Note that another control frame (e.g., Buffer Status Request frame, P2P Buffer Status Request frame, etc.) may be used instead of the BSRP.

[0169] For example, when STA2 (relay destination STA) receives the BSRP, it transmits a PPDU including the BSR to STA1. At this time, the AP may be specified by the Destination Address or the like.

[0170] STA1 receives the PPDU including the BSR transmitted from STA2 and transfers the PPDU to the AP.

[0171] When the AP is notified by BSR that there is data to be transmitted from the relay destination STA to the AP, the AP may perform, for example, the UL transmission procedure (relay operation) shown in Fig. 36. Note that Fig. 36 shows the UL transmission procedure described in Method 4 as an example, but the UL transmission procedure may be any of Methods 1 to 3 and Methods 5 to 7.

[0172] (Method 9) Method 9 is a method that applies BSR collection and transmission in the relay operation described in Methods 1 to 7, and is different from Method 8.

[0173] For example, as shown in Fig. 37, STA1 (relay STA) transmits a frame (e.g., BSRP) to STA2 (relay destination STA) requesting transmission of information (e.g., BSR) regarding the presence or absence of transmission data. Note that, instead of the BSRP, another control frame (e.g., Buffer Status Request frame, P2P Buffer Status Request frame, etc.) may be used. Furthermore, the information regarding the presence or absence of transmission data may include, for example, the amount of data, requested BW (Bandwidth), TID, AC, etc.

[0174] For example, when STA2 (the relay destination STA) receives the BSRP, it transmits a PPDU including information (e.g., a BSR) regarding the presence or absence of data to be transmitted to STA1. The BSR may include, for example, buffer information regarding data addressed to the relay STA and / or data to be transmitted to the AP via the relay STA (e.g., relayed). For example, the BSR may distinguish each piece of data by a TID or a Destination Address (e.g., an AID).

[0175] STA1, for example, may receive a BSRP from the AP and respond by including in the BSR at least one of buffer information regarding data from STA1 (relay STA) addressed to the AP and buffer information regarding data transmitted from STA2 (relay destination STA) to the AP via the relay STA.

[0176] When the AP is notified by BSR that there is data to be transmitted from a relay STA or a relay destination STA to the AP, the AP may perform, for example, the UL transmission procedure (relay operation) shown in Fig. 37. Note that Fig. 37 shows the UL transmission procedure described in Method 4 as an example, but the UL transmission procedure may be any of Methods 1 to 3 and Methods 5 to 7.

[0177] (Method 10) In Method 1, an example of an operation for deleting Ack transmissions that can be reduced as shown in Fig. 10 has been described, but the operation for deleting Ack transmissions may also be applied to DL data transmissions using Relay operation. For example, Ack transmissions may be deleted in the DL transmission method using Relay operation shown in Fig. 1.

[0178] FIG. 38 shows an example of an operation for deleting Ack transmission in a DL transmission method using Relay.

[0179] As shown in FIG. 38, after the AP transmits PPDU1, the Ack transmitted from STA1 to the AP may be deleted.

[0180] The AP may detect whether STA1 has started transmitting PPDU2 SIFS after receiving PPDU1 by attempting to detect a signal for a specified time (e.g., PIFS or DIFS) after transmitting PPDU1. For example, the operation of STA1 successfully receiving PPDU1 and transmitting PPDU2 in response is equivalent to the operation of STA1 successfully receiving PPDU1 and transmitting an Ack in response. Therefore, the AP's detection of whether PPDU2 transmission has started is equivalent to the AP's detection of the reception of an Ack. Therefore, when the AP detects the start of PPDU2 transmission, it may consider that it has received an Ack for PPDU1. This makes it possible to delete the Ack sent from STA1 to the AP, preventing unnecessary Ack transmissions and improving throughput.

[0181] Also, in Figure 38, for example, STA2 can transmit and receive both DL and UL data, but may apply Relay to transmit DL data at a higher MCS. In this case, as shown in Figure 38, the Ack transmitted by STA2 can be received by the AP, and STA1 does not need to forward the Ack from STA2 to the AP. In this case, STA1 may delete the operation of forwarding the Ack from STA2 to the AP, and the AP may receive the Ack from STA2. This prevents unnecessary Ack forwarding and improves throughput.

[0182] The AP may instruct STA1 whether or not it is necessary to transfer an Ack from STA2. For example, when a relay operation is applied to transmit at a higher MCS (for example, when an Ack from STA2 can be received), the AP may instruct STA1 that it is not necessary to transfer an Ack from STA2. Also, for example, the instruction that it is not necessary to transfer an Ack from STA2 may be assigned the Common Info field of the TXOP Shearing trigger or Reserved in User Info shown in FIG. 38.

[0183] Furthermore, the AP may notify STA1, or STA2 in addition to STA1, that the DL data transmission is performed using the relay operation. This notification may be performed using, for example, Reserved (for example, value = 3) in the Triggered TXOP Sharing Mode subfield included in the TXOP Shearing trigger, or the above-mentioned Relay Control element.

[0184] Methods 1 to 10 have been described above.

[0185] As described above, in this embodiment, AP 200 controls relay operations for the destination STA that performs UL transmission and the relay STA that relays the UL transmission, and receives the UL transmission signal. This enables relaying of UL transmission from STA 100 to AP 200. Therefore, according to this embodiment, it is possible to improve the efficiency of transmission control in wireless communication.

[0186] The embodiments of the present disclosure have been described above.

[0187] Note that, in Methods 2 to 9, operational examples using an MU-RTS Trigger frame or a Basic Trigger frame have been described, but the type of Trigger frame is not limited to these, and other triggers may be used. For example, a new trigger (e.g., a "Relay Trigger frame") may be used. For example, the Relay Trigger frame may have a Trigger Type subfield value of 9. In this case, the format of the Relay Trigger frame may be the same as the format of the MU-RTS Trigger frame or the Basic Trigger frame shown in Methods 2 to 9. This makes it possible to prevent an operational example in which Trigger Dependent User Info is added from being configured to add Trigger Dependent User Info only in a specific mode using the same trigger.

[0188] Furthermore, in Methods 1 to 9, operation examples of UL transmission methods using a relay have been described. However, Methods 1 to 9 may also be applied to DL transmission using a relay. In this case, the AP may specify DL / UL transmission (unidirectional) of data to the relay STA as well as to the relay destination STA, or may specify DL / UL bidirectional transmission in addition to unidirectional transmission. For example, when DL transmission is specified, the DL transmission method described in FIG. 1 or Method 10 may be performed. DL / UL transmission may be specified, for example, using Reserved included in the trigger or a Relay Control element. For example, FIG. 39 shows an example format in which a data transmission direction indication (e.g., "DL / UL mode") and an indication of whether Ack transfer is required (e.g., "Ack Send") shown in Methods 1 and 10 are added to the Reserved field in User Info of the MU-RTS Trigger shown in FIG. 16. In FIG. 39, the DL / UL mode may be, for example, "0: DL transmission, 1: UL communication, 2: bidirectional communication." In Fig. 39, Ack Send may be, for example, "0: Ack transfer required, 1: Ack transfer not required." In addition, Fig. 40 shows an example format in which the above-mentioned DL / UL mode and Ack Send are added to the Relay Control element shown in Fig. 18.

[0189] Furthermore, in methods 1 to 9, for example, when a destination STA performs a relay operation to transmit at a higher MCS, the destination STA can receive a trigger transmitted by the AP, eliminating the need for the relay STA to perform a trigger forwarding operation to the destination STA. If the destination STA can receive a trigger transmitted from the AP, the AP may instruct the relay STA that trigger forwarding is not required. For example, "Ack Send" shown in Figures 39 and 40 may be used as a flag indicating whether trigger forwarding is required in addition to indicating whether Ack forwarding is required (e.g., "Ack Send" may be changed to "Ack and Trigger Send"), or a flag indicating whether trigger forwarding is required may be added to the trigger or relay control element.

[0190] Furthermore, in methods 1 to 10, the frequency band for transmission and reception between the AP and the relay STA and the frequency band for transmission and reception between the relay STA and the relay destination STA may be different frequency bands. For example, the frequency band for transmission and reception between the relay STA and the relay destination STA may be changed (or set) to a frequency band including the primary CH of the relay destination STA, and in the MLD configuration, the link for transmission and reception between the AP and the relay STA and the link for transmission and reception between the relay STA and the relay destination STA may be different links.

[0191] In the above-described embodiment, the field (or subfield) used for notifying the control information is an example, and other fields or subfields may be used. Furthermore, the number of bits used for notifying the control information in each field or subfield is an example, and other numbers of bits may be used.

[0192] Furthermore, in the above-described embodiment, the values ​​of the control information to be notified (for example, the values ​​of AID, Element ID, Element ID Extension, and Type) are merely examples, and other values ​​may be used.

[0193] Furthermore, the signal format described in the above-mentioned embodiment is an example, and other configurations may be used in which at least one of other fields is added and some fields is deleted, and other configurations may be used in which at least one of other subfields is added and some subfields are deleted in each of the above-mentioned fields.

[0194] Furthermore, in the above embodiment, as an example, a case based on the format defined in IEEE 802.11 has been described, but the format to which an embodiment of the present disclosure is applied is not limited to the IEEE 802.11 format.

[0195] The present disclosure can be realized by software, hardware, or software in conjunction with hardware. Each functional block used in the description of the above embodiments may be partially or entirely realized as an LSI, which is an integrated circuit, and each process described in the above embodiments may be partially or entirely controlled by a single LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of a single chip that includes some or all of the functional blocks. The LSI may have data input and output. Depending on the degree of integration, the LSI may also be called an IC, system LSI, super LSI, or ultra LSI.

[0196] The integrated circuit method is not limited to LSI, and may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. Also, a field programmable gate array (FPGA) that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells within the LSI, may be used. The present disclosure may be realized as digital processing or analog processing.

[0197] Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology or other derivative technologies, it is natural that such technology may be used to integrate functional blocks. The application of biotechnology, etc. is also a possibility.

[0198] The present disclosure may be implemented in any type of apparatus, device, or system (collectively referred to as a communications apparatus) that has a communications function. The communications apparatus may include a radio transceiver and processing / control circuitry. The radio transceiver may include a receiver and a transmitter, or both functions. The radio transceiver (transmitter and receiver) may include a radio frequency (RF) module and one or more antennas. The RF module may include an amplifier, an RF modulator / demodulator, or the like. Non-limiting examples of communication devices include telephones (e.g., cell phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, notebooks), cameras (e.g., digital still / video cameras), digital players (e.g., digital audio / video players), wearable devices (e.g., wearable cameras, smartwatches, tracking devices), game consoles, digital book readers, telehealth / telemedicine devices, communication-enabled vehicles or mobile transportation (e.g., cars, airplanes, ships), and combinations of the above devices.

[0199] The communication devices are not limited to portable or mobile devices, but also include any kind of non-portable or fixed equipment, devices, and systems, such as smart home devices (such as home appliances, lighting equipment, smart meters or measuring devices, control panels, etc.), vending machines, and any other "things" that may exist on an IoT (Internet of Things) network.

[0200] Communications include data communications via cellular systems, wireless LAN systems, communication satellite systems, and the like, as well as data communications via combinations of these.

[0201] A communications apparatus also includes devices such as controllers and sensors connected or coupled to a communications device that performs the communications functions described in this disclosure, such as controllers and sensors that generate control and data signals used by the communications device to perform the communications functions of the communications apparatus.

[0202] The communication apparatus also includes infrastructure facilities, such as base stations, access points, and any other apparatus, device, or system that communicates with or controls the various apparatuses listed above, but are not limited to these.

[0203] An access point according to one embodiment of the present disclosure includes a control circuit that controls relay operations for at least one of a first terminal that performs uplink transmission and a second terminal that relays the uplink transmission, and a receiving circuit that receives the uplink transmission signal in accordance with the control of the relay operation.

[0204] In one embodiment of the present disclosure, the relay device further comprises a transmitting circuit for transmitting control information related to the relay operation.

[0205] In one embodiment of the present disclosure, the control information is included in at least one of a trigger frame, a control frame, and an element.

[0206] In one embodiment of the present disclosure, the control information is transferred from the second terminal to the first terminal.

[0207] In one embodiment of the present disclosure, the transmission control of the uplink transmission differs between when the relay operation is performed and when the relay operation is not performed.

[0208] In one embodiment of the present disclosure, the encryption or decryption process for the uplink transmission signal differs between when the relay operation is performed and when the relay operation is not performed.

[0209] In one embodiment of the present disclosure, the control information includes an instruction for uplink transmission to another terminal different from the first terminal, and a first transmission frequency band of the control information transferred by the second terminal to the first terminal is different from a second transmission frequency band of the signal for the uplink transmission by the other terminal.

[0210] In one embodiment of the present disclosure, the control information specifies a third transmission frequency band for the uplink transmission by the first terminal, and the first transmission frequency band is set within the third transmission frequency band.

[0211] In one embodiment of the present disclosure, if the first terminal does not receive the control information from the access point, the control information is forwarded from the second terminal to the first terminal, and if the first terminal receives the control information from the access point, the control information is not forwarded from the second terminal to the first terminal.

[0212] In one embodiment of the present disclosure, the control information controls whether or not to transfer the control information from the second terminal to the first terminal.

[0213] In one embodiment of the present disclosure, the control information controls whether or not the second terminal transmits a response signal in response to the uplink transmission signal from the first terminal.

[0214] A terminal according to one embodiment of the present disclosure includes a control circuit that controls relay operations for other terminals that perform uplink transmissions based on control information from an access point, and a transmission circuit that transmits the uplink transmission signals from the other terminals to the access point in accordance with the control of the relay operations.

[0215] In a communication method according to one embodiment of the present disclosure, an access point controls relay operations for at least one of a first terminal that performs uplink transmission and a second terminal that relays the uplink transmission, and receives the uplink transmission signal in accordance with the control of the relay operations.

[0216] In a communication method according to one embodiment of the present disclosure, a terminal controls relay operations for other terminals performing uplink transmission based on control information from an access point, and transmits the uplink transmission signals from the other terminals to the access point in accordance with the control of the relay operations.

[0217] The disclosures of the specification, drawings and abstract contained in Japanese Patent Application No. 2023-118346, filed on July 20, 2023, are incorporated herein by reference in their entirety.

[0218] One embodiment of the present disclosure is useful in wireless communication systems.

[0219] 100 STA 101 Wireless transmission / reception unit 102 Received packet decoding unit 103 Relay control unit 104 Control signal generation unit 105 Transmitted packet generation unit 200 AP 201 Scheduling unit

Claims

1. An access point comprising: a control circuit that controls relay operation for at least one of a first terminal that performs uplink transmission and a second terminal that relays the uplink transmission; and a receiving circuit that receives the uplink transmission signal in accordance with the control of the relay operation.

2. The access point according to claim 1, further comprising a transmission circuit for transmitting control information relating to said relay operation.

3. The access point according to claim 2, wherein the control information is included in at least one of a trigger frame, a control frame, and an element.

4. The access point according to claim 2, wherein the control information is transferred from the second terminal to the first terminal.

5. The access point according to claim 1, wherein the transmission control of the uplink transmission differs between a case where the relay operation is performed and a case where the relay operation is not performed.

6. The access point according to claim 1, wherein a process of encryption or decryption for the uplink transmission signal differs between when the relay operation is performed and when the relay operation is not performed.

7. The access point of claim 2, wherein the control information includes an instruction for uplink transmission to another terminal different from the first terminal, and a first transmission frequency band of the control information transferred by the second terminal to the first terminal is different from a second transmission frequency band of the signal for the uplink transmission by the other terminal.

8. The access point of claim 7, wherein the control information specifies a third transmission frequency band for the uplink transmission by the first terminal, and the first transmission frequency band is set within the third transmission frequency band.

9. The access point of claim 2, wherein if the first terminal does not receive the control information from the access point, the control information is transferred from the second terminal to the first terminal, and if the first terminal receives the control information from the access point, the control information is not transferred from the second terminal to the first terminal.

10. The access point according to claim 9, wherein said control information controls whether or not said control information is transferred from said second terminal to said first terminal.

11. The access point according to claim 2, wherein the control information controls whether or not the second terminal transmits a response signal to the uplink transmission signal from the first terminal.

12. A terminal comprising: a control circuit that controls relay operation for other terminals performing uplink transmission based on control information from an access point; and a transmission circuit that transmits the uplink transmission signal from the other terminal to the access point in accordance with the control of the relay operation.

13. A communication method, in which an access point controls relay operation for at least one of a first terminal performing uplink transmission and a second terminal relaying the uplink transmission, and receives the uplink transmission signal in accordance with the control of the relay operation.

14. A communications method in which a terminal controls relay operation for other terminals performing uplink transmission based on control information from an access point, and transmits the uplink transmission signal from the other terminal to the access point in accordance with the control of the relay operation.

Images