Communication device, communication method, and program

Abstract

To efficiently specify a device that can execute relay communication when using relay communication in communication between an access point and a station.SOLUTION: A communication device operating as an access point conforming to the IEEE802.11 series standard can execute, in communication between the communication device and a station, a first communication method of performing communication via another station device that performs relay of a data frame, and a second communication method of performing direct communication, acquires, from the station device, first capability information indicating that the station device has a first capability for executing the first communication method, when the station device has the first capability, selects one of the first communication method and the second communication method as a communication method used in communication with the station device, and when the station device does not have the first capability, selects the second communication method, and performs communication with the station device on the basis of a result of the selection.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a technique for relaying data frames in communication between an access point and a station. [Background technology]

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

[0003] For the successor to the IEEE 802.11be standard, studies are being conducted with the aim of further improving throughput and expanding communication range. For example, in addition to a direct communication method in which communication is performed directly between an access point (hereinafter, AP) and a station (hereinafter, STA), a relay communication method using a relay communication device is being considered. Relay communication may also be called relay communication. In the relay communication method, a STA, which is a relay communication device, receives a data frame transmitted by an AP and transmits the data frame to another STA, or receives a data frame transmitted by another STA and transmits the data frame to the AP. For example, Patent Document 1 describes the use of a trigger frame defined in the IEEE 802.11 series of standards for controlling relay communication. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-72638 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a technique for efficiently identifying a device capable of performing relay communication when relay communication is used in communication between an access point and a station. [Means for solving the problem]

[0006] A communication device according to one embodiment of the present invention is a communication device capable of operating as an access point compliant with the IEEE 802.11 series standard, and comprises: communication means capable of executing a first communication method in which communication is performed via another station device that relays data frames, and a second communication method in which communication is performed directly, in communication between the communication device and a station device; acquisition means for acquiring first capability information from the station device indicating that the station device has a first capability for executing the first communication method; and selection means for selecting either the first communication method or the second communication method as the communication method to be used in communication with the station device if the station device has the first capability, and selecting the second communication method if the station device does not have the first capability, and the communication means communicates with the station device based on the result of the selection. [Effects of the Invention]

[0007] According to the present invention, when relay communication is used in communication between an access point and a station, it is possible to efficiently identify a device capable of performing relay communication. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. [Figure 2] FIG. 2 illustrates an example of a hardware configuration of a communication device. [Figure 3] FIG. 2 is a diagram illustrating an example of a functional configuration of an AP. [Figure 4] FIG. 10 is a diagram illustrating an example of the functional configuration of an STA. [Figure 5] FIG. 10 is a schematic diagram illustrating an example of a time chart when a communication device establishes a connection. [Figure 6] FIG. 10 is a diagram illustrating an example of a UHR Capability element. [Figure 7] FIG. 10 is a diagram illustrating an example of a UHR Operation element. [Figure 8] FIG. 10 is a diagram illustrating an example of a UHR Protected Action frame. [Figure 9] FIG. 10 is a schematic diagram illustrating an example of a time chart when a communication device establishes a connection. [Figure 10] FIG. 10 is a diagram illustrating an example of a UHR Protected Action frame. [Figure 11] 10 is an example of a processing flow executed by an AP. [Figure 12] 10 is an example of a processing flow executed by an STA. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0010] (System Configuration) FIG. 1 shows an example of the configuration of a wireless communication system according to this embodiment. The wireless communication system includes, for example, an access point (AP) 101 and stations (STAs) 111 and 112. In this embodiment, the STAs 111 and 112 may be collectively referred to as STAs 110. The AP 101 and STAs 110 may be collectively referred to as communication devices 100. The AP 101 and STAs 110 are each communication devices capable of performing wireless communication in accordance with the IEEE 802.11 series standards. IEEE stands for Institute of Electrical and Electronics Engineers. FIG. 1 shows a configuration in which the STAs 111 and 112 participate in a network 131 established by the AP 101. The network 131 may also be referred to as a Basic Service Set (BSS). The STA 110's participation in the network 131 may be referred to as the STA 110 belonging to the network 131 (or the AP 101). The AP 101 and the STAs 111 are connected using a wireless channel 121. AP 101 and STA 112 are connected using wireless channel 122. STA 111 and STA 112 can be connected using wireless channel 123. The geographical distance between AP 101 and STA 111 is assumed to be longer than both the distance between AP 101 and STA 112 and the distance between STA 111 and STA 112. For example, STA 112 is assumed to be located between AP 101 and STA 111. While network 103 in FIG. 1 shows a configuration in which one AP 101 and two STAs 110 exist, there may be multiple APs, or there may be three or more STAs. In this case, multiple STAs may be connected to one AP, or one STA may be connected to multiple APs.

[0011] In this embodiment, the communication device 100 is configured to be able to execute a communication method compliant with a successor standard to the IEEE 802.11. For example, the communication device 100 is configured to be able to execute a communication method compliant with the IEEE 802.11bn standard. The IEEE 802.11bn standard is a successor standard to the IEEE 802.11be standard, which targets a maximum transmission speed of 46.08 Gbps (Giga bit per second). The main features of the IEEE 802.11bn standard are its functions of realizing highly reliable communication, low latency communication, and improved throughput when communication traffic is congested. The IEEE 802.11bn standard may also be referred to as the UHR standard. The communication device 100 may execute a communication method compliant with a successor standard to the IEEE 802.11bn standard. The communication device 100 may also support at least one legacy standard that predates the IEEE 802.11bn standard. The legacy standard is, for example, the IEEE 802.11a / b / g / n / ac / ax / be standard. The communication device 100 may also support other communication standards, such as Bluetooth (registered trademark), NFC, UWB, ZigBee, and MBOA. UWB stands for Ultra Wide Band, and MBOA stands for Multi-Band OFDM Alliance. NFC stands for Near Field Communication. UWB includes wireless USB, wireless 1394, WiNET, and the like. The communication device 100 may also support communication standards, such as a wired LAN. The AP 101 may be, for example, a wireless LAN router or a personal computer (PC), but is not limited to these. The AP 101 may also be an information processing device, such as a wireless chip, capable of performing wireless communication compliant with the IEEE 802.11bn standard. The STA 110 may be, for example, a camera, a tablet, a smartphone, a PC, a mobile phone, a video camera, a headset, or the like, but is not limited to these. The STA 110 may be an information processing device such as a wireless chip capable of performing wireless communication conforming to the IEEE802.11bn standard, etc. The STA 110 may also be a communication device having an AP function.

[0012] Communication device 100 may communicate using radio signals in frequency bands such as the 2.4 GHz band, 3.6 GHz band, 5 GHz band, and 6 GHz band, as well as the 45 GHz band and 60 GHz band known as millimeter waves. The frequency bands used by communication device 100 are not limited to these and may be, for example, the Sub-1 GHz band. Communication device 100 may also communicate using bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, 540 MHz, 640 MHz, 1080 MHz, and 2160 MHz. The bandwidths used by communication device 100 are not limited to these and may be, for example, 240 MHz, 4 MHz, etc.

[0013] The IEEE 802.11 series of standards specifies a function for increasing communication speeds by performing multi-user (MU) communication, in which an AP multiplexes wireless resources to communicate simultaneously with multiple STAs. For example, an AP may communicate with multiple STAs in parallel using OFDMA communication. OFDMA stands for Orthogonal Frequency Division Multiple Access. In OFDMA communication, portions of a divided frequency band (Resource Units, or RUs) are allocated to communications between the AP and each STA so that they do not overlap. In OFDMA communication, the carriers used for communications between the AP and each STA are orthogonal on the frequency axis. This configuration utilizing orthogonality on the frequency axis allows the AP to communicate with multiple STAs in parallel within a single specified bandwidth. The AP allocates RUs to each STA. The AP 101 may also communicate with multiple STAs in parallel using multi-user MIMO (Multiple-Input and Multiple-Output) communication. In this case, the AP has multiple antennas, and different signals are transmitted from each antenna using the same frequency channel. Each STA simultaneously receives the signals transmitted from each antenna, separates the signals, and decodes them. In MIMO communication, the propagation paths used for communication between the AP and each STA are spatially orthogonal. This spatial orthogonality allows the AP to communicate with multiple STAs in parallel within a single specified bandwidth. In this way, by performing multi-user communication, the AP can communicate more data with each STA in the same amount of time than if multi-user communication were not performed.

[0014] Generally, in a communication method conforming to the IEEE 802.11 series of standards, the AP 101 communicates with the STA 110 by directly exchanging wireless frames. The available communication method may vary depending on the distance between the AP 101 and the STA 110. For example, in FIG. 1, the STA 112 is closer to the AP 101 than the STA 111, and therefore may use a more efficient communication method. Here, the communication method may be, for example, a modulation method, a coding method, a MIMO multiplexing number, a guard interval length, a frequency bandwidth, or the like. That is, when the distance between the communication devices 100 is short, the RSSI and SNR are high, and therefore a highly efficient communication method, such as a modulation method with a high number of modulation levels or a coding method with low redundancy, may be used. RSSI is an abbreviation for Received Signal Strength Indicator, and is also referred to as received signal strength. Furthermore, SNR is an abbreviation for Signal-to-Noise Ratio, and is also referred to as signal-to-noise ratio. That is, a STA located far from the AP may use a less efficient communication method, and therefore the communication capacity of the entire network may decrease. Furthermore, as the distance between the AP and the STA increases, the error rate of wireless frames may increase. In such a situation where the distance between the AP and the STA is large, it may be possible to improve the efficiency and stability of communication by having another STA relay the communication between these communication devices. For example, in FIG. 1, communication between the AP 101 and the STA 111 may be performed via relay by the STA 112, which may improve the efficiency compared to direct communication between the AP 101 and the STA 111. However, in order to relay communication between communication devices, each communication device must be capable of performing relayed communication, and each communication device must be able to recognize that the other communication device can perform relayed communication. Here, the STA 112 that performs relaying may be called a relay STA. Furthermore, the STA 111, which is the communication partner of the AP 101, may be called an end STA. In this embodiment, the terms relay and relay are interchangeable.

[0015] In consideration of these circumstances, the AP in this embodiment performs first communication with an end STA using relay via a relay STA when a predetermined condition is met. Communication using a relay STA may be called relay communication. For example, the AP 101 may communicate with the end STA 111 via the relay STA 112. On the other hand, when the predetermined condition is not met, the AP 101 performs second communication in which the end STA 111 communicates directly with the end STA without using relay. For example, the AP 101 may acquire first capability information indicating that the end STA 111 has a first capability for performing relay communication. Then, if the end STA 111 has the first capability, the AP 101 selects either the first communication method or the second communication method to perform communication. Furthermore, if the end STA 111 does not have the first capability, the AP 101 selects the second communication method to perform communication. Furthermore, the end STA 111 may notify the AP 101 of first capability information indicating that the end STA 111 has the first capability for performing relay communication. The end STA 111 may communicate with the AP 101 based on the selection by the AP 101. Furthermore, the relay STA 112 may notify the AP 101 of capability information indicating that the STA 112 has a predetermined capability for performing relaying. The AP 101 may determine, based on this capability information, whether to use the STA 112 as a relay STA in the communication between the AP 101 and the end STA 111. The relay STA 112 may then relay the communication between the AP 101 and the end STA 111 based on this determination. With this configuration, the AP 101 can determine whether each STA 110 is capable of performing relayed communication. Meanwhile, the AP 101 may notify the STA 110 of second capability information indicating that the AP 101 has a second capability for performing relayed communication. The STA 110 may obtain the second capability information from the AP 101. With this configuration, the STA 110 can determine whether the AP 101 is capable of performing relayed communication.

[0016] The first capability for performing relay communication may be that the end STA 111 receives a data frame from the relay STA 112 based on an instruction from the AP 101. The first capability for performing relay communication may be that the end STA 111 transmits a data frame to the relay STA 112 based on an instruction from the AP 101. The first capability for performing relay communication may be that the end STA 111 instructs the relay STA 112 to relay to the AP 101. The first capability for performing relay communication may be that the end STA 111 transmits a data frame to the relay STA 112 based on an instruction from the AP 101. The first capability for performing relay communication may be that the end STA 111 can transmit using a frame in a format for relay communication. Also, the first capability for performing relay communication may be that the end STA 111 can receive using a frame in a format for relay communication. The first capability for performing relay communication may be that the end STA 111 can communicate a frame using a frame exchange procedure for relay communication. The first capability for performing relay communication may be that the end STA 111 is capable of communicating using a communication method for relay communication. For example, the communication method may be a modulation method, an encoding method, a data multiplexing method, an encryption method, etc. The first capability for performing relay communication may be that the end STA 111 is capable of processing frames for relay communication. Processing frames for relay communication may include extracting data frames from frames for relay communication and encapsulating data frames into frames for relay communication. Furthermore, processing frames for relay communication may include converting headers of frames for direct communication into a frame format for relay communication, converting headers of frame formats for relay communication into headers for direct communication, etc.

[0017] The second capability for performing relay communication may be that the AP 101 instructs the relay STA 112 to relay to the end STA 111. The second capability for performing relay communication may be that the AP 101 instructs the end STA 111 to perform relay communication. The second capability for performing relay communication may be that the AP 101 determines whether to perform direct communication or relay communication with the end STA 111. The second capability for performing relay communication may be that the AP 101 is capable of transmitting using frames in a format for relay communication. The AP 101 may be capable of transmitting using frames in a format for relay communication. The second capability for performing relay communication may be that the AP 101 is capable of receiving using frames in a format for relay communication. The second capability for performing relay communication may be that the AP 101 is capable of communicating frames using a frame exchange procedure for relay communication. The second capability for performing relay communication may be that the AP 101 is capable of communicating using a communication method for relay communication. A second capability for performing relay communication may be that the AP 101 is capable of processing frames for relay communication.

[0018] The predetermined capability for performing relaying may be that the relay STA 112 relays communication between the AP 101 and the end STA 111 based on instructions from the AP 101. The predetermined capability for performing relaying may be that the relay STA 112 is capable of transmitting using frames in a format for relay communication. The predetermined capability for performing relaying may be that the relay STA 112 is capable of receiving using frames in a format for relay communication. The predetermined capability for performing relaying may be that the relay STA 112 is capable of communicating frames using a frame exchange procedure for relay communication. The predetermined capability for performing relaying may be that the relay STA 112 is capable of communicating using a communication method for relay communication. The predetermined capability for performing relaying may be that the relay STA 112 is capable of processing frames for relay communication.

[0019] The AP 101 may also acquire the communication quality between itself and the end STA 111, the communication quality between itself and the relay STA 112, and the communication quality between the end STA 111 and the relay STA 112. Based on these communication qualities, the AP 101 may determine whether communication with the end STA 111 should be performed by direct communication or by relay communication via the relay STA 112. The communication quality may be acquired, for example, by measuring the RSSI, SNR, data rate, delay time, etc. when receiving a wireless frame. The wireless frame may include a data frame, a management frame, a control frame, etc. This configuration enables the AP 101 to select whether communication with each STA 110 should be performed directly or by relay, based on the status of the network 131. The device configurations, functional configurations, and processing flows of the AP 101, the end STA 111, and the relay STA 112 are described below.

[0020] (Device configuration) 2 shows an example of the hardware configuration of the communication device 100 (AP 101 and STA 110) according to this embodiment. As an example of the hardware configuration, the communication device 100 has, for example, a storage unit 201, a control unit 202, a function unit 203, an input unit 204, an output unit 205, a communication unit 206, and an antenna 207. The communication device 100 may have multiple antennas.

[0021] The storage unit 201 is configured with one or more memories including ROM, RAM, etc., and may store various information such as control programs for each functional unit constituting the communication device 100 to perform various operations, and parameters for communication. ROM and RAM stand for Read Only Memory and Random Access Memory, respectively. In addition to memories such as ROM and RAM, the storage unit 201 may also be configured to include storage media such as a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory card, and a DVD.

[0022] The control unit 202 is configured with one or more processors including, for example, a CPU, an MPU, etc., and controls the entire communication device 100 by executing a control program stored in the storage unit 201. The control unit 202 may control the entire communication device 100 in cooperation with the control program stored in the storage unit 201 and an OS (Operating System). The CPU and MPU are abbreviations for Central Processing Unit and Micro Processing Unit, respectively. When the control unit 202 has multiple processors that can be implemented using a multi-core or the like, the entire communication device 100 may be configured to be controlled by the multiple processors.

[0023] Furthermore, the control unit 202 controls the functional unit 203 to execute predetermined processes such as communication, image capture, printing, and projection. The functional unit 203 is hardware that enables the communication device 100 to execute the predetermined processes described above. For example, if the device is a camera, the functional unit 203 is an image capture unit that performs image capture processing. Also, for example, if the device is a printer, the functional unit 203 is a print unit that performs print processing. Also, for example, if the device is a projector, the functional unit 203 is a projection unit that performs projection processing.

[0024] The input unit 204 receives various operations from the user. The output unit 205 outputs various types of information to the user via a monitor screen or a speaker. The output from the output unit 205 may be a display on a monitor screen, an audio output from a speaker, a vibration output, or the like. The input unit 204 and the output unit 205 may both be implemented as a single module, such as a touch panel. The input unit 204 and the output unit 205 may be integrated into the communication device 100 or may be separate devices.

[0025] The communication unit 206 controls wireless communication compliant with the IEEE 802.11bn standard. The communication unit 206 may also control wireless communication compliant with other IEEE 802.11 series standards, such as legacy standards, in addition to the IEEE 802.11bn standard. The communication unit 206 controls the antenna 207 to transmit and receive signals for wireless communication generated by the control unit 202. The communication unit 206 is a so-called wireless chip and may itself include one or more processors and memories. If the communication device 100 supports other wireless communication standards, such as the NFC standard or the Bluetooth standard, or wired communication, such as a wired LAN, in addition to the IEEE 802.11bn standard, the communication unit 206 may control communication compliant with these communication standards. If the communication device 100 can perform wireless communication compliant with multiple communication standards, the communication device 100 may be configured to have separate communication units and antennas compatible with each communication standard. The communication device 100 communicates data with a partner communication device via the communication unit 206. The antenna 207 may be configured as a separate unit from the communication unit 206, or may be configured together with the communication unit 206 as a single module.

[0026] Antenna 207 is an antenna capable of communication in, for example, the 2.4 GHz band, the 5 GHz band, the 6 GHz band, millimeter waves, etc. Although Fig. 2 shows a configuration in which communication device 100 has two antennas 207, communication device 100 may have one or three or more antennas, or may have one or more antennas for each frequency band that the device can use. Furthermore, if communication device 100 has multiple antennas, communication device 100 may have a communication unit 206 for each antenna.

[0027] (Functional configuration) The functional configuration of the communication device 100 (AP 101 and STA 110) in this embodiment will be described. FIG. 3 shows an example of a block diagram of the AP 101. The AP 101 may be configured to include a data frame processing unit 301, a communication frame transmitting / receiving unit 302, an information acquisition unit 303, a relay control unit 304, a relay condition determination unit 305, and a frame analysis unit 306. The AP 101 may also be configured to include an information notification unit 307, an STA list notification unit 308, and a request reception unit 309. The data frame processing unit 301 processes data frames to be transmitted or received data frames. When the AP 101 transmits data, it generates a data frame. When the AP 101 receives data, it performs reception processing for the received data frame. The communication frame transmitting / receiving unit 302 transmits and receives frames to be communicated with the STA. For example, the communication frame transmitting / receiving unit 302 may transmit a Beacon frame, a Probe Response frame, an Authentication frame, and an Association Response frame. The communication frame transmitting / receiving unit 302 may transmit management frames such as a Reassociation Response frame, a BA (Block Ack) frame, and an Action frame, as well as data frames. For example, the communication frame transmitting / receiving unit 302 may receive a Probe Request frame, an Association Request frame, and a Reassociation Request frame. The communication frame transmitting / receiving unit 302 may also receive management frames such as a BA (Block Ack) frame and an Action frame, as well as data frames. The information acquiring unit 303 acquires information about the STA 110. For example, the information acquiring unit 303 may acquire information about the STA 110 from a frame received by the communication frame transmitting / receiving unit 302. The information about the STA 110 may be, for example, capability information about the STA 110. The relay control unit 304 controls relay communication. For example, when relay communication is performed with an end STA, the relay control unit 304 transmits and receives trigger frames and data frames via the communication frame transmitting / receiving unit 302. The relay condition determining unit 305 determines conditions related to relay communication.For example, the relay condition determination unit 305 selects whether to perform direct communication or relay communication with the end STA. The frame analysis unit 306 analyzes a frame received by the communication frame transmission / reception unit 302. The information notification unit 307 notifies information related to the device itself. For example, the information notification unit 307 may use the communication frame transmission / reception unit 302 to notify a frame including information related to the device itself. The information related to the device itself may be, for example, capability information of the device itself. The STA list notification unit 308 notifies information related to relay STAs. For example, the STA list notification unit 308 notifies information that can identify STAs that can operate as relay STAs. The request reception unit 309 receives a request from the STA 110. For example, the request reception unit 309 may receive a request to use or not use relay communication from the STA 110.

[0028] FIG. 4 shows an example of a block diagram of the STA 110. The STA 110 may include a data frame processing unit 401, a communication frame transmitting / receiving unit 402, an information acquisition unit 403, a relay control unit 404, an AP function execution unit 405, and a frame analysis unit 406. The STA 110 may also include an information notification unit 407, an STA list acquisition unit 408, and a request transmission unit 409. The data frame processing unit 401 processes data frames to be transmitted or received, similar to the data frame processing unit 301. The communication frame transmitting / receiving unit 402 transmits and receives frames for communication with the AP. For example, the communication frame transmitting / receiving unit 402 may receive Beacon frames, Probe Response frames, Authentication frames, and Association Response frames. The communication frame transmitting / receiving unit 402 may also receive management frames such as Reassociation Response frames, BA (Block Ack) frames, and Action frames, as well as data frames. For example, the communication frame transceiver 402 may transmit a Probe Request frame, an Association Request frame, and a Reassociation Request frame. The communication frame transceiver 402 may also transmit management frames such as a Block Ack (BA) frame and an Action frame, and data frames. The information acquirer 403 acquires information about the AP 101. For example, the information acquirer 403 may acquire information about the AP 101 from a frame received by the communication frame transceiver 402. The information about the AP 101 may be, for example, capability information about the AP 101. The relay control unit 404 controls relay communication. For example, when relay communication is performed with the AP 101, the relay control unit 404 transmits and receives trigger frames and data frames via the communication frame transceiver 402. The AP function execution unit 405 executes some of the same functions as those executed by the AP when operating as a relay STA. For example, the AP function execution unit 405 transmits beacons and performs connection processing with other STAs. The frame analysis unit 406 analyzes the frame received by the communication frame transmission / reception unit 402 .The information notification unit 407 notifies information related to the own device. For example, the information notification unit 407 may use the communication frame transmission / reception unit 402 to notify a frame including information related to the own device. The information related to the own device may be, for example, capability information of the own device. The STA list acquisition unit 408 acquires information related to relay STAs. For example, the STA list acquisition unit 408 acquires information that can identify STAs that can operate as relay STAs. The request transmission unit 409 transmits a request from the STA 110. For example, the request transmission unit 409 may transmit a request to use or not use relay communication to the AP 101.

[0029] (Processing example) A connection procedure between communication devices 100 in this embodiment will be described. Fig. 5 is a diagram showing an example of a message sequence between communication devices 100. This example shows a connection procedure when AP 101 communicates with STA 111 via STA 112. In this embodiment, a communication method in which a relay STA relays communication between an AP and an end STA is referred to as relay communication. Furthermore, STA 112 that relays in relay communication is referred to as a relay STA.

[0030] (Notification of AP101's capabilities) First, the AP 101 notifies capability information indicating that the AP 101 is capable of performing relay communication (F501). For example, the AP 101 may notify capability information using a beacon that it periodically transmits. The AP 101 may also notify capability information using a method other than beacon notification. For example, the AP 101 may notify capability information using a probe response or the like. The capability information indicating that the AP 101 is capable of performing relay communication may be notified using a UHR Capability element included in a beacon or the like. Note that, although the present invention will be described assuming the use of a UHR Capability element, this element is not limited to this, and other elements such as a UHR MAC capability element or a Multi Link element may also be used. The HR MAC capability element is an element capable of notifying MAC layer information. The Multi Link element is an element capable of notifying capability information for each link when communicating using multiple links. FIG. 6 shows an example of the configuration of a UHR Capability element. The UHR Capability element includes an Element ID field 601, a Length field 602, and an Extended Element ID field 603. The UHR Capability element may also include a Relay Transmit Capable field 604 and a Relay Receive Capable field 605. The UHR Capability element may also include a Relay AP Capable field 606 and a Relay STA Capable field 607. The Element ID field 601 and the Extended Element ID field 603 indicate that this element is a UHR Capability element. For example, if the Element ID field 601 is set to 255 and the Extended Element ID field 603 is set to 138, this indicates that this element is a UHR Capability Element. The Length field 602 indicates the length of this element.

[0031] The Relay Transmit Capable field 604 indicates that the source device of a wireless frame including this element is capable of transmitting using relay communication. For example, the AP 101 may use this field to indicate that it can transmit data frames to the end STA 111 through the relay STA 112. As an example, setting this field to 1 may indicate that it can transmit data frames to the end STA 111 through the relay STA 112. The Relay Receive Capable field 605 indicates that the source device of a wireless frame including this element is capable of receiving using relay communication. For example, the AP 101 may use this field to indicate that it can receive data frames transmitted by the end STA 111 through the relay STA 112. As an example, setting this field to 1 may indicate that it can receive data frames from the end STA 111 through the relay STA 112. Note that the Relay Transmit Capable field 604 and the Relay Receive Capable field 605 may be combined. In this case, the combined field or bit indicates that communication using relay communication is possible. That is, it can be shown that both sending and receiving operations using relay communication are feasible.

[0032] The Relay AP Capable field 606 and the Relay STA Capable field 607 are fields used when the STA 110 transmits a UHR Capability element, and will be described in detail later. For example, the AP 101 may set both the Relay AP Capable field 606 and the Relay STA Capable field 607 to 0.

[0033] (Notification of relay STA112 capability information and connection processing) When the STA 112 detects an AP, it executes a connection process (F502). For example, the STA 112 may execute the connection process by transmitting a Probe Request, an Association Request, an Authentication, etc., and receiving a response from the AP 101 in response to these. Furthermore, when the STA 112 acquires capability information indicating that the AP 101 is capable of relay communication via a Beacon, a Probe Response, etc., it may notify the AP 101 of its own capability information in the connection process. For example, the STA 112 may transmit a Probe Request, an Association Request, an Authentication, etc. frame including capability information indicating that the STA 112 is capable of relay communication. For example, the STA 112 may transmit these frames including a UHR Capability element. The STA 112 may notify the AP 101 that it can operate as a relay STA using the Relay AP Capable field 606 and the Relay STA Capable field 607. The Relay AP Capable field 606 and the Relay STA Capable field 607 indicate that the source device of a wireless frame containing these elements can operate as a relay STA in relay communication. That is, when either of these fields is set to 1, it indicates that the source device is capable of receiving a data frame transmitted by the AP 101 and transmitting it to another STA. Similarly, it indicates that the source device is capable of receiving a data frame transmitted by another STA and transmitting it to the AP 101. Note that when the Relay AP Capable field 606 is set to 1, it may indicate that the source device can operate as a relay STA capable of performing some of the functions performed by an AP. On the other hand, when the Relay STA Capable field 607 is set to 1, it may indicate that the source device operates as a relay STA but does not perform some of the functions performed by the AP described above. Some of the functions performed by an AP will be described later.Note that the ability to operate as a relay STA may be indicated in one field instead of the Relay AP Capable field 606 and the Relay STA Capable field 607. In this case, another field may indicate whether the source STA 112 performs some of the same functions as the AP.

[0034] (Notification of list of relay STAs) The AP 101 may share the list of STAs capable of operating as relay STAs with communication devices other than the AP 101 (F503). For example, when a connection procedure between the AP 101 and the STA 112 is completed, a connection between the AP 101 and the STA 112 is established. When the AP 101 acquires capability information indicating that the STA 112 can operate as a relay STA in relay communication during the connection procedure, the AP 101 stores the STA 112 as a STA that can be used as a relay STA when the AP 101 performs relay communication. Such a STA that can be used as a relay STA is referred to as a candidate STA. The AP 101 may create a list of candidate STAs. The AP 101 may then share the list of candidate STAs with communication devices other than the AP 101. For example, the AP 101 may notify the list of candidate STAs using a beacon that it periodically transmits. The list of candidate STAs may include first identification information that can identify each candidate STA. The first identification information that can identify the candidate STA may be the MAC address of the candidate STA. The list of candidate STAs may also include second identification information that can identify the operating parameters of each candidate STA. The second identification information may include the size of A-MSDU or A-MPDU that the candidate STA can handle, frequency bandwidth, whether STBC is enabled, etc. A-MSDU is an abbreviation for Aggregate Medium Access Control (MAC) Service Data Unit. A-MPDU is an abbreviation for Aggregate Medium Access Control (MAC) Protocol Data Unit. STBC is an abbreviation for Space Time Block Coding. The second identification information may also include information that can identify the number of wireless links that the candidate STA can use and each link. Note that the first and second identification information are not limited to these. The AP 101 may notify the list of candidate STAs using a method other than notification by beacon. This allows each STA 110 belonging to the AP 101 to identify relay STAs that can be used when the AP 101 performs relay communication. For example, the AP 101 may notify the list of candidate STAs using a probe response, etc.

[0035] The list of candidate STAs can be notified using a UHR Operation element included in a Beacon or the like. Fig. 7 shows an example of the configuration of a UHR Operation element. The UHR Operation element includes an Element ID field 701, a Length field 702, and an Extended Element ID field 703. The UHR Operation element can also include a UHR Control field 704, a Relay STA List field 705, and a Relayed AP Address field 706. The Element ID field 701 and the Extended Element ID field 703 are the same as the Element ID field 601 and the Extended Element ID field 603. The values ​​can be 255 and 139, respectively. The Length field 702 indicates the length of this element.

[0036] The UHR Control field 704 includes a Relay STA List present field 711 and a Relayed AP Address present field 711. The Relay STA List present field 710 indicates whether the Relay STA List field 705 is present in the subsequent field. If the Relay STA List field 705 is present, 1 may be set thereto. The Relayed AP address present field 711 indicates whether the Relayed AP address field 706 is present in the subsequent field. If the Relayed AP address field 706 is present, 1 may be set thereto.

[0037] The Relay STA List field 705 indicates the list of candidate STAs described above. That is, when the AP 101 performs relay communication, information is indicated that can identify the STA 110 that can perform relay operation as a relay STA. The Relay STA List field 705 includes a STA Number field 721 and one or more STA Info fields 722. The STA Number field 721 indicates the number of subsequent STA Info fields. For example, if the AP 101 establishes connections with two STAs 110 and both of them can operate as relay STAs, the STA Number field 721 is set to 2. In this case, the Relay STA List field 705 can include two STA Info fields. Note that the Relay STA List field 705 may further include a Length field, and the Length field may indicate the length of the Relay STA List field 705.

[0038] Each STA Info field 722 contains information about a candidate STA included in the list. The STA Info field 722 may include a Relay STA Address field 731, a MAX A-MSDU Length field 732, and a Bandwidth field 733. The STA Info field 722 may also include a MAX A-MPDU Length field 734, an STBC field 735, and a Relay Parameter field 736. The Relay STA Address field 731 indicates the MAC address of the candidate STA. The MAX A-MSDU Length field 732 indicates the maximum size of an A-MSDU in a radio frame that the candidate STA can handle when operating as a relay STA. When the value of the MAX A-MSDU Length field 732 is 0 or 1, respectively, the maximum A-MSDU size may correspond to 3839 octets or 7935 octets, respectively. The STA Info field 722 may further include a Max Number Of Fragmented MSDU / A-MSDU field (not shown). The Max Number Of Fragmented MSDU / A-MSDU field may indicate the maximum number of fragments a received MSDU may be fragmented into when the candidate STA operates as a relay STA. In this case, the received MSDU may be transmitted in fragmented units. The Bandwidth field 733 indicates the maximum frequency bandwidth that the candidate STA can use when operating as a relay STA. For example, the values ​​0, 1, 2, 3, and 4 of the Bandwidth field 733 may correspond to frequency bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz, respectively. The MAX A-MPDU Length field 734 indicates the maximum size of an A-MPDU that the candidate STA can handle when operating as a relay STA. For example, the values ​​0, 1, and 2 of the MAX A-MPDU Length field 734 may correspond to the maximum A-MPDU sizes of 3895 octets, 7991 octets, and 11454 octets, respectively.The maximum size of the A-MPDU may be expressed in other ways, for example, 2, where α is the value of the MAX A-MPDU Length field 734. 13 ×2 α In this representation, 2 13 is 2 20 or 2 23 Alternatively, instead of subtracting 1, it may be subtracted by 16500631 or 115523200. The STBC field 735 indicates whether the candidate STA is capable of STBC transmission and reception when operating as a relay STA. The STBC field may be configured to include an STBC TX field and an STBC RX field. In this case, the STBC TX field may indicate whether STBC transmission is possible, and the STBC RX field may indicate the number of receivable streams.

[0039] The Relay Parameter field 736 indicates operation parameters when the candidate STA operates as a relay STA. The Relay Parameter field 736 includes a Link Number field 741, one or more Link ID fields 742, and a TID mapping field 743. The Link Number field 741 indicates the maximum number of Links that the candidate STA can use simultaneously when operating as a relay STA. For example, the Link Number field 741 may be set to a value obtained by subtracting 1 from the number in the following Link ID field 742. The Link ID field 742 indicates the value of a Link ID that the candidate STA can use for relaying when operating as a relay STA. Note that a field indicating a Channel value that can be used for relaying may be included instead of a Link ID. In this case, a field indicating an Operating Class may be included in addition to the field indicating the Channel value, so that the frequency band in which the Channel is set may be indicated. The TID mapping field 743 indicates the association between each Link that the candidate STA can use when operating as a relay STA and a TID. TID is an abbreviation for Traffic Identifier. Note that the TID mapping field 743 may be represented by a bitmap. As an example, the TID mapping field 743 may be configured such that multiple bits corresponding to the TIDs for one link are provided, and the bit corresponding to the TID associated with that link is set to 1. In this case, one different bit may be provided for each of the communication directions, uplink and downlink. Note that instead of the TID mapping field 743, a TID-To-Link Mapping element defined in the IEEE 802.11be standard may be used.

[0040] The fields included in the Relay Parameter field 736 are not limited to these, and may include, for example, information on each field included in the STA Info 722. The STA Info field 722 may also include a field included in an HT Capability element, a VHT Capability element, or an EHT Capability element. The STA Info field 722 may also include a field included in a UHR Capability element or an Extended Capability element. Alternatively, the above fields included in the STA Info field 722 may be included in another element of the radio frame for notification. For example, the above fields may be included in an HT Capability element, a VHT Capability element, or an EHT Capability element. The STA Info field 722 may also be included in a UHR Capability element or an Extended Capability element. In these cases, the STA Info field 722 may include information indicating that information on the candidate STA is included in another element. In other words, information about the AP 101 included in another element may be notified as information on the candidate STA.

[0041] The Relayed AP address field 706 is a field used in a Beacon transmitted when the STA 110 operates as a relay STA, and will be described in detail later.

[0042] As described above, the capability information of the AP 101 and the list of candidate STAs are notified in the Capability element and Operation element of the Beacon transmitted by the AP 101. This enables the STA 110 belonging to the AP 101 to determine whether the AP 101 supports relay communication and to identify candidate STAs that can operate as relay STAs for relay communication. Note that the information included in the UHR Operation element may be notified by other elements. For example, it may be notified using a Wrapped Data element. This allows the information included in the Relay STA List field 705 to be encrypted and notified. Encryption allows only STAs that have established a connection with the AP 101 to obtain the information of the candidate STAs included in the Relay STA List field 705. For example, it is possible to prevent man-in-the-middle attacks, such as spoofing a relay STA.

[0043] (Notification of capability information of end STA111 and connection processing) When the STA 111 detects an AP, it performs a connection process (F504). For example, the STA 111 may perform the connection process by transmitting a Probe Request, Association Request, Authentication, or the like and receiving a response from the AP 101 in response to these. Furthermore, when the STA 111 acquires capability information indicating that the AP 101 is capable of relay communication via a Beacon, Probe Response, or the like, it may notify the AP 101 of its own capability information during the connection process. For example, the STA 111 may transmit a Probe Request, Association Request, Authentication, or other frame containing capability information indicating that the STA 111 is capable of relay communication. For example, the STA 111 may transmit these frames including a UHR Capability element. The STA 111 may use the Relay Transmit Capable field 604 to notify the AP 101 that it can transmit data frames via the relay STA 112. For example, a value of 1 in this field may indicate that the STA 111 can transmit data frames to the AP 101. Furthermore, the STA 111 may use the Relay Receive Capable field 605 to notify that the STA 111 can receive data frames from the AP 101 via relay by the relay STA. As an example, if this field is set to 1, it may indicate that the STA 111 can receive data frames from the AP 101 through the relay STA 112. When the AP 101 receives a Probe Request including information indicating the capability information of the STA 111, the AP 101 transmits a Probe Response including a UHR Capability element indicating the capability information of the STA 111 (F505). Upon receiving the Probe Response, the STA 111 may confirm that the AP 101 is capable of performing relay communication. This allows the AP 101 and the STA 111 to mutually confirm that each other is capable of performing relay communication.STA 111 may obtain a list of candidate STAs that can operate as relay STAs based on a UHR Operation element included in a Beacon, Probe Response, Association Response, or the like. This allows STA 111 to ascertain candidate STAs when communicating with AP 101 using relay communication. For example, STA 111 may recognize STA 112 as a candidate STA. If the list of STAs that can operate as relay STAs is periodically transmitted by Beacon, STA 111 can obtain the updated list by receiving Beacon, even if the contents of the list are changed after the connection process is completed.

[0044] (Determining whether to perform relay communication in AP) When a connection is established between the AP 101 and the STA 111, the AP 101 may determine whether to perform relay communication in communication with the STA 111. The AP 101 may determine whether to perform relay communication based on the establishment of a connection with the STA 111, periodically, or each time data frames are communicated. For example, the AP 101 may make this determination by measuring the communication environment between the AP 101 and the STA 111. As an example, the AP 101 may make this determination by acquiring from the STA 111 the reception quality at the STA 111 of radio waves transmitted from the AP 101 itself and the reception quality at the STA 111 of radio waves transmitted from the STA 112. First, the AP 101 may send a notification to the STA 111 requesting measurement of communication quality (F507, F508). This notification may be made using an SNR Request frame. The SNR Request frame may be sent directly from the AP 101 to the STA 111 or via the STA 112. When the notification is made via STA 112, an SNR Request frame is transmitted from AP 101 to STA 112 (F507), and an SNR Relay frame may be transmitted from STA 112 to STA 111 (F508). For example, when there are multiple candidate STAs, AP 101 may transmit an SNR Request frame to each of the candidate STAs. By transmitting an SNR Relay frame from each candidate STA to STA 111, the communication quality when relay communication is performed using each candidate STA as a relay STA can be measured. FIG. 5 shows an example in which AP 101 requests communication quality measurement via STA 112. The SNR Request frame may be included in a UHR Protected Action frame. FIG. 8(A) shows an example of an SNR Request frame. The UHR Protected Action frame includes a Category field 801, a Protected UHR Action field 802, and a Dialog Token field 803.The UHR Protected Action frame may also include a Relay Control field 804 and a Dest STA Address field 805 or an SNR List field 806 .

[0045] The Category field 801 stores an identification number indicating Protected UHR. For example, a value of 40 may be set thereto. The Protected UHR Action field 802 indicates an identifier of this Action field in the Protected UHR category. For example, if this Action field is a Relay Mode Notification Frame Action field, the Protected UHR Action field 802 may be set to 2. The Dialog Token field 803 indicates an identifier that uniquely identifies a series of information exchanges between the AP 101 and the STA 111. For example, an identifier assigned by the AP 101 that transmitted the SNR Request frame is stored in the Dialog Token field 803. In response to the SNR Request frame, the STA 111 stores the value contained in the received Dialog Token field 803 in the Dialog Token field 803 of a response frame and transmits the response frame.

[0046] The Relay Control field 804 includes a Relay Action field 811. The Relay Action field 811 indicates a value corresponding to a process to be performed in relation to relay communication, as shown in Table 1. For example, in the case of an SNR Request frame transmitted in F507, the Relay Action field 811 may be set to 2. Also, in the case of an SNR Relay frame transmitted in F508, the Relay Action field 811 may be set to 3. Note that in the case of SNR Response frames transmitted in F509 and F510, the Relay Action field 811 may be set to 3. Table 1 The SNR Request frame may include a Destination STA Address field 805. The Destination STA Address field 805 indicates the STA 110 that should perform communication quality measurement. For example, the Destination STA Address field 805 may include the MAC address or AID of the STA 110 that should perform SNR measurement. AID is an abbreviation for Association ID. The Destination STA Address field 805 may be expressed in a manner other than these, as long as it includes information that uniquely identifies the STA 110 that should perform communication quality measurement. In this example, the AP 101 may include information that identifies the STA 111 in the Destination STA Address field 805 to determine whether relay communication is possible in communication with the STA 111 and to identify the relay STA to be used for relay communication. When the SNR Request frame is forwarded to the destination STA 110 via one or more STAs 110, each STA 110 that receives the SNR Request frame may measure communication quality. In this case, each STA 110 that has performed communication quality measurement can add the measurement results to an SNR Relay frame or an SNR Response frame, which will be described later.

[0047] A candidate STA that receives an SNR Request frame may generate an SNR Relay frame. For example, when STA 112 receives an SNR Request frame that includes information identifying STA 111 in the Destination STA Address field 805, it may generate an SNR Relay frame addressed to STA 111. This allows each candidate STA to notify STA 111, which is to measure communication quality, of a measurement request. The SNR Relay frame may also include information on the communication quality measured by STA 110 that transmitted this frame. In other words, STA 110 transmitting an SNR Relay frame may transmit an SNR Relay frame that includes the results of communication quality measurements performed before transmission. FIG. 8B shows an example of an SNR Relay frame. The SNR Relay frame may include an SNR List field 806. The SNR List field 806 includes a Measure STA Num field 821 and a Measure STA Address field 822. The SNR List field 806 also includes a Measured STA Num field 823 , a Measured Address field 824 , an RSSI field 825 , and an SNR field 826 .

[0048] The Measure STA Num field 821 indicates the number of STAs 110 that performed the measurement of the communication quality included in this field. For example, in the case of the SNR Relay frame in F508, the measurement result of the communication quality measured by the STA 112 may be included, and therefore the Measure STA Num field 821 may be set to a value of 0. This may indicate that the number of STAs 110 that performed the measurement of the communication quality is 1. The Measure STA Address field 822 includes information that identifies the STA 110 that performed the measurement of the communication quality. For example, in the case of the SNR Relay frame in F508, the MAC address of the STA 112 or the like may be included. The Measured STA Num field 823 indicates the number of communication devices 100 that were the targets of the measurement of the communication quality. For example, in the SNR Relay frame in F508, if the target of the measurement of the communication quality by the STA 112 was only the AP 101, the Measured STA Num field 823 may be set to a value of 0. This may indicate that the number of communication devices 100 that were the targets of the measurement of the communication quality is 1. The Measured Address field 824 includes information for identifying the communication device 100 that is the target of communication quality measurement. For example, in the SNR Relay frame in F508, if the target of communication quality measurement by the STA 112 is only the AP 101, the MAC address and BSSID of the AP 101 may be set in the Measured Address field 824. The RSSI field 825 and the SNR field 826 include information for identifying the measurement result. For example, if the STA 110 that performed the measurement acquired the RSSI based on a signal received from the communication device 100 that is the target of measurement, the measurement result is set in the RSSI field 825. Furthermore, if the STA 110 that performed the measurement acquired the SNR based on a signal received from the communication device 100 that is the target of measurement, the measurement result is set in the SNR field 826.

[0049] When the STA 111 receives an SNR Request frame transmitted from the AP 101 to the STA 111 itself or an SNR Relay frame transmitted from the relay STA 112 to the STA 111 itself, the STA 111 performs measurement of communication quality. The STA 111 also notifies the AP 101 or the relay STA 112 of the measurement results. The STA 111 may notify the AP 101 of the measurement results directly or via the relay STA 112. The notification of the measurement results may be performed using an SNR Response frame. When notifying via the relay STA 112, the STA 111 transmits an SNR Response frame to the STA 112 (F509), and in response to receiving this frame, the STA 112 may transmit an SNR Response frame to the AP 101 (F510). The SNR Response frame may be a UHR Protected Action frame with the Relay Action field set to 4. The SNR Response frame may include an SNR List 806, similar to the SNR Relay frame. The SNR Response frame may include the communication quality measurement results included in the SNR Relay frame that triggered the generation of this frame and the SNR Response frame. For example, in F509, the SNR Response frame transmitted from STA 111 may include the communication quality measurement results measured by STA 111 and the measurement results included in the SNR Relay frame. In this case, the Measure STA Num field 821 may be set to a value of 1, indicating that the number of STAs 110 that performed the communication quality measurement is two. The SNR Response frame may include, following the Measure STA Num field 821, a Measure STA Address field 822 for each STA 110 that performed the communication quality measurement. That is, each Measure STA Address field 822 may include information identifying STA 111 and STA 112. The SNR Response frame may also include one Measured STA Num field 823 for each Measure STA Address field 822.That is, when one STA 110 measures the communication quality of a plurality of communication devices 110, the number of communication devices 100 whose communication quality was measured may be indicated by the respective Measured STA Num fields 823. For example, when STA 111 measures communication quality based on signals received from each of AP 101 and STA 112, 1 may be set in the Measured STA Num field 823. In this case, it may be indicated that the number of communication devices 100 whose communication quality was measured is 2. The SNR Response frame may also include a Measured Address field 824 corresponding to each of the communication devices 100 whose communication quality was measured. That is, the MAC addresses of the AP 101 and the STA 112 may be set in each Measured Address field 824. The SNR Response frame may also include an RSSI field 825 and an SNR field 826 corresponding to each of the measurement results based on signals received from each of the communication devices 100 whose communication quality was measured. In this way, the measurement result of the communication quality between the AP 101 and the STA 112 by the STA 111 can be reported using one SNR Response frame. As described above, the SNR Response frame can include the measurement result of the communication quality by the STA 112, which was included in the SNR Relay frame, in addition to the measurement result of the communication quality by the STA 111. The measurement result of the communication quality by the STA 112 can be included in a field following the field indicating the measurement result of the communication quality by the STA 111. When the STA 111 receives SNR Relay frames addressed to the STA 111 from multiple relay STAs, the STA 111 can report the measurement result to one relay STA. This can reduce the consumption of radio resources compared to reporting the measurement result via each relay STA. In this case, each relay STA can include the measurement result of the communication quality measured between the STA 111 and the STA 111 in the SNR Relay frame.This allows the SNR Request frame and SNR Relay frame to be relayed, and the measurement results of communication quality between each communication device to be accumulated and notified in bulk from STA111 to AP101, so that the measurement results can be notified efficiently.

[0050] When the STA 112 receives the SNR Response frame transmitted from the STA 111 to the STA 112, the STA 112 generates an SNR Response frame addressed to the AP 101. As described above, the SNR Response frame generated by the relay STA 112 may include the measurement result included in the SNR Response frame received from the STA 111. Furthermore, if the relay STA 112 measures communication quality based on a signal received from the STA 111 after transmitting the SNR Relay frame to the STA 111, the relay STA 112 may include the measurement result in the SNR Response frame. Therefore, in the case of an SNR Response frame transmitted from the STA 112 in F510, the measurement result of the communication quality measured by the STA 112 and the measurement result included in the SNR Response frame in F509 may be included. For example, the Measure STA Num field 821 may be set to a value of 1, indicating that the number of STAs 110 that performed communication quality measurements is two. Furthermore, the Measured STA Num field 823 following the field indicating the relay STA 112 as the Measure STA Address field 822 is set to 1. That is, it may indicate that the number of communication devices 100 that were the targets of communication quality measurement is two. Furthermore, in each of the subsequent Measured Address fields 824, the MAC addresses and the like of AP 101 and STA 111 are set, and it may indicate that STA 112 measured communication quality targeting AP 101 and STA 111. Furthermore, following this, an RSSI field 825 and an SNR field 826 may be included that correspond to measurement results based on signals received from AP 101 and STA 111, respectively, that were the targets of communication quality measurement.

[0051] The AP 101 may acquire the results of reception quality measurements from the relay STA 112 using the SNR Response frames received from the relay STA 112. For example, the reception quality of a signal from the AP 101 at each of the STA 111 and the STA 112, and the reception quality of a signal from a counterpart communication device at each of the STA 111 and the STA 112 may be acquired. Based on these communication qualities, the AP 101 may determine whether to perform communication with the STA 111 directly or by relay communication via the STA 112. For example, the AP 101 may determine to perform relay communication if both the communication quality between the AP 101 and the STA 112 and the communication quality between the AP 101 and the STA 111 are higher than the communication quality between the AP 101 and the STA 111. The method by which the AP 101 determines whether to perform relay communication is not limited to the above. For example, AP 101 may determine to perform relay communication if a value indicating the communication quality between itself and STA 111 is lower than a predetermined threshold, and both the communication quality between itself and STA 112 and the communication quality between STA 111 and STA 112 are higher than predetermined thresholds. AP 101 may then perform communication with STA 111 using the determined communication method (F511, F512).

[0052] The STA 110 may measure communication quality using a predetermined frame. For example, the STA 110 may perform measurement using the received power when receiving an SNR Request frame, an SNR Response frame, an SNR Relay frame, or the like. The method by which the STA 110 measures communication quality is not limited to this. For example, the transmitting STA 110 may transmit a Null Data Packet and the receiving STA 110 may perform measurement using the received power when receiving the Null Data Packet. The STA 110 may also perform measurement using the received power of a Beacon transmitted from the AP 101 or a data frame previously received from the AP 101. The STA 110 may also notify the measurement results using a CSI Report frame instead of an SNR Response frame. The configuration of the SNR List field 806 may be different from the configuration shown in FIG. 8(B). For example, the Measured Address field 824 may be eliminated by fixing the order of the RSSI fields 825 and SNR fields 826 associated with each of the communication devices 100 to be measured. In addition to or instead of the RSSI field 825 and the SNR field 826, the value of a communicable MCS (Modulation and coding scheme) may be notified.

[0053] The above describes an example in which the AP 101 determines whether to perform relay communication based on the communication quality between the AP 101 and the candidate STA 112, the communication quality between the candidate STA 112 and the end STA 111, and the SNR between the AP 101 and the end STA 111. This determination can be made using measurement information other than SNR. For example, the measurement information can include SINR, transmission delay time, and frame error rate. SINR can be an abbreviation for Signal to Interference and Noise Ratio. The method for determining whether to perform relay communication is not limited to these, and the AP 101 may determine whether to perform relay communication based on information other than communication quality. For example, the AP 101 may determine whether to perform relay communication based on the geographical distance between the AP 101 and the end STA 111 or location information of the end STA 111. The AP 101 may also determine whether to perform relay communication based on traffic characteristics, such as the required delay for traffic communicated with the end STA.

[0054] The AP 101 may determine whether to perform relay communication between the AP 101 and the STA 111 based on a request from the STA 111. For example, the STA 111 may receive a list of candidate STAs notified by the AP 101. The STA 111 may also receive frames, such as data frames, transmitted from other STAs 110 in the BSS to which the STA 111 belongs. At this time, the STA 111 may determine the communication quality with each STA 110 based on the received power of the received frame. If a value indicating the communication quality exceeds a predetermined threshold and the frame was transmitted from a candidate STA, the STA 111 may notify the AP 101 of the measurement result. The STA 111 may also notify the AP 101 of the communication quality between the AP 101 and the STA 111. For example, the STA 111 may notify the AP 101 of the measurement result via the candidate STA that was the subject of the measurement using an SNR Response. In this case, before transmitting an SNR Response to AP 101, the candidate STA may measure the communication quality between itself and STA 111 and the communication quality between itself and AP 101, and notify the AP of an SNR Response including the results. As a result, AP 101 may obtain the communication quality between itself and STA 111, the communication quality between itself and STA 112, and the communication quality between STA 111 and STA 112. Based on these results, AP 101 may determine whether to perform relay communication in communication with STA 111. With this configuration, STA 111 determines whether to perform relay communication and measures the communication quality for candidate STAs with high communication quality, thereby enabling efficient use of wireless resources and processing resources.

[0055] (Notification of whether or not to perform relay communication at the end STA) STA 111 may request to use or not use relay communication in communication with AP 101. FIG. 9 is a diagram showing another example of a message sequence between communication devices 100. The same reference numerals are assigned to the same processes as in FIG. 5, and descriptions thereof will be omitted. That is, it is assumed that a connection has been established between AP 101 and STA 112 (F501 to F502) and between AP 101 and STA 111 (F504 to F505). It is also assumed that STA 112 is capable of operating as a relay STA in communication between AP 101 and STA 111 (F503, F506). After establishing a connection with AP 101, STA 111 may request AP 101 to use or not use relay communication. For example, in FIG. 9, STA 111 requests not to use relay communication (F901). In this case, STA 111 may make the request using a UHR Protected Action frame in which the value of the Relay Action field 811 is set to 0. A UHR Protected Action frame in which the value of the Relay Action field 811 is set to 0 may be a Relay Mode Request frame. An example of the structure of a Relay Mode Request frame is shown in Fig. 10. In Fig. 10, the same reference numerals are used for the same components as in Fig. 8, and descriptions thereof will be omitted. That is, the Relay Mode Request frame includes a Relay Control field 804, a Relay Mode field 1001, and a Relay Parameter Update field 1002. The Relay Control field 804 includes a Relay Action field 811 and a Relay Parameter Update Present field 1012. The Relay Action field 811 may be set to 0 as described above. The Relay Parameter Update Present field 1012 indicates whether or not a subsequent Relay Parameter Update field 1002 is present.

[0056] The Relay Mode field 1001 indicates whether or not relay communication is to be used. For example, the Relay Mode field 1001 may be a field for switching between enabling and disabling relay communication. As an example, the STA 111 may indicate that relay communication is to be used by setting this field to 1, and indicate that relay communication is to be used by setting this field to 0. In FIG. 9 , setting the Relay Mode field 1001 to 0 may indicate that relay communication is not to be used. Note that one Relay Mode field 1001 may be provided for each of the uplink and downlink. For example, setting the Relay Mode field 1001 corresponding to the uplink to 1 indicates that relay communication is to be used in the direction from the STA 111 to the AP 101. Setting the Relay Mode field 1001 corresponding to the downlink to 0 indicates that relay communication is not to be used in the direction from the AP 101 to the STA 111. When the delay required for the uplink and the downlink differs depending on the application executed by the STA 110, higher communication performance may be expected by using relay communication in the direction requiring a lower delay.

[0057] The Relay Parameter Update field 1002 indicates parameters used during relay communication. For example, the Relay Parameter Update field 1002 may include the TID mapping field 743. The Relay Parameter Update field 1002 may also include other parameters. For example, it may include the Link Number field 741, the Link ID field 742, etc. shown in FIG. 7. The Relay Parameter Update field 1002 may also include the STA Info field 722.

[0058] When the AP 101 receives a Relay Mode Request frame from the STA 111, the AP 101 may respond with a Relay Mode Response frame. The Relay Mode Response frame may include a Status Code field. The AP 101 may use the Status Code field to notify whether or not it accepts the request indicated in the Relay Mode Request frame. For example, the Status Code field may include information indicating success if the request is accepted, or information indicating the reason for not accepting the request if the request is not accepted. The Relay Mode Response frame may include some or all of the fields shown in FIG. 10.

[0059] If the AP 101 accepts the request from the STA 111 via the Relay Mode Request frame, it transmits a data frame directly to the STA 111 (F902). This configuration allows the STA 111 to switch whether or not to perform relay communication depending on its own device status. For example, if the STA 111 is a portable device, control can be performed depending on the remaining battery level, the running status of an application in the STA 111, the allowable delay and total amount of data handled by the application, etc. Note that, when the AP 101 determines whether or not to perform relay communication, it can notify the STA 111 of its decision by transmitting a Relay Mode Request frame. This allows the AP 101 to notify the STA 111 of whether or not to perform relay communication depending on the STA 110 connected to the AP 101. Note that the request for whether or not to perform relay communication can be executed only if the AP 101 and the STA 111 support relay communication. Furthermore, when the Relay Mode field 1001 is provided for each of the uplink and downlink, the AP 101 and the STA 111 can request that only communication in the supported direction be used based on the capability information notified by the AP 101 or the Beacon when establishing a connection. Since a request to use relay communication in a communication direction that is not supported by the communication partner cannot be used even if a request is made, such a configuration can avoid wasting wireless resources and power of the device itself.

[0060] (Processing flow in AP101) FIG. 11 shows an example of a processing flow when the AP 101 determines whether to perform relay communication. This processing may be the processing of the AP 101 when the AP 101 in FIG. 1 operates as an AP and the STA 111 connects to the AP 101. Note that this processing may be repeatedly executed after a connection with the STA 111 is established. First, the AP 101 executes a connection process with the STA 111 (S1101). In the connection process, the AP 101 acquires capability information of the STA 111. For example, the AP 101 determines whether a UHR Capability element is included in a received Association Request frame or Probe Request frame (S1102). If the UHR Capability element is not included (NO in S1102), the AP 101 may determine that the STA 111 does not support the UHR function and may not use relay communication in communicating data frames (S1106). In other words, the AP 101 may choose to communicate data frames directly with the STA 111. On the other hand, if the UHR Capability element is included (YES in S1102), the AP 101 acquires the values ​​of the Relay Transmit Capable field 604 and the Relay Receive Capable field 605. If the value of each field is 0 (NO in S1103), the AP 101 determines that the STA 111 does not support relay communication functionality and may select to perform direct communication without using relay communication in data frame communication (S1106). If the value of at least one field is 1 (YES in S1103), the AP 101 stores this information as indicating that the STA 111 has relay communication functionality (S1104). That is, the AP 101 may select either direct data frame communication with the STA 111 or relay communication based on subsequent processing. Note that if one of the Relay Transmit Capable field 604 and the Relay Receive Capable field 605 is 1 and the other is 0, normal transmission and reception processing is performed for the communication direction corresponding to the setting of 0 (S1106).In this case, a determination is made as to whether or not to execute relay communication for a communication direction corresponding to relay communication. For example, assume that the Relay Transmit Capable field 604 is 1 and one of the Relay Receive Capable fields 605 is 0. Assume also that the AP 101 is capable of executing relay processing for both transmission and reception. In this case, the AP 101 may execute the processing from S1104 onward when receiving a data frame from the STA 111, and may execute the processing from S1106 when transmitting a data frame to the STA 111. On the other hand, if the AP 101 is capable of transmission using relay communication but not reception, the AP 101 may execute the processing from S1106 for both communication directions. In other words, the processing from S1104 onward may be executed for a communication direction in which both the AP 101 and the STA 111 can execute relay communication. During the connection process, the AP 101 may acquire capability information indicating that the STA 111 can operate as a relay STA. For example, the AP 101 may acquire capability information indicating that the STA 111 can operate as a relay STA using a UHR Operation element. If the STA 111 is capable of acting as a relay STA, the AP 101 may store the STA 111 as a candidate STA.

[0061] The processing from S1105 onwards will be described. The AP 101 determines whether relay communication can be used when communicating data frames with the STA 111 (S1105). Whether relay communication can be used can be switched, for example, by exchanging a Relay Mode Request frame and a Relay Mode Response frame between the AP 101 and the STA 111. For example, the default setting when the STA 111 connects to the AP 101 may enable relay communication. In this case, the AP 101 or the STA 111 may notify a Relay Mode Request frame for disabling (disabling) relay communication. Furthermore, when relay communication is disabled, the AP 101 or the STA 111 may notify a Relay Mode Request frame for enabling (enabling) relay communication. If relay communication is disabled (NO in S1105), the AP 101 performs the processing of S1106. If relay communication is enabled (YES in S1105), the AP 101 performs the processing of S1107.

[0062] When transmitting a data frame (YES in S1107), the AP 101 determines whether there is a candidate STA that can serve as a relay STA in communication with the STA 111 (S1108). If there is no candidate STA (NO in S1108), the AP 101 decides to communicate directly with the STA 111 (S1112). On the other hand, if there is a candidate STA (YES in S1108), the AP 101 checks the communication quality between the AP 101 and the candidate STA and the communication quality between the candidate STA and the STA 111. For example, the AP 101 may determine whether the SNR is sufficiently high as the communication quality of each. As an example, the AP 101 may determine that the communication quality is sufficient if a value indicating each communication quality exceeds a predetermined threshold. If the AP 101 determines that any of the communication qualities is insufficient, the AP 101 decides to communicate directly with the STA 111 (S1112). If the AP 101 determines that both communication qualities are sufficient, the AP 101 determines whether to perform relay communication. For example, the AP 101 may determine whether to perform relay communication by determining whether the communication quality between the AP 101 and the STA 111 is sufficient. As an example, the AP 101 may determine that the communication quality is sufficient when the SNR of the signal received from the STA 111 exceeds a predetermined threshold, and may determine not to perform relay communication (NO in S1110). If it is determined not to perform relay communication, the AP 101 may communicate directly with the STA 111 (S1112). Furthermore, the AP 101 may determine that the communication quality is insufficient when the SNR of the signal received from the STA 111 is below a predetermined threshold, and may determine to perform relay communication (YES in S1110).

[0063] When performing relay communication, the AP 101 transmits a data frame to the end STA 111 via the relay STA 112 (S1111). For example, the AP 101 may transmit a signal to reserve a period required for relay communication in advance, and transmit the data frame to the relay STA 112 within that period. As an example, the AP 101 may reserve a period required for relay communication by transmitting a Trigger frame. For example, a period including a period for the AP 101 to transmit a data frame to the relay STA 112 and a period for the relay STA 112 to transmit a data frame to the end STA 111 may be set in the Duration field of the Trigger frame. In addition, the Duration field may also include a period for the end STA 111 to return an ACK or BlockACK. In this case, a period including a period for the end STA 111 to transmit an ACK or BlockACK to the relay STA 112 and a period for the relay STA 112 to transmit an ACK or BlockACK to the AP 101 may be set in the Duration field in addition to the above periods. The settings in the Duration field are not limited to these, and may be set to, for example, a period required for the procedure for performing relay communication, which will be described later. In this way, relay communication can be performed using the period secured by the Trigger frame.

[0064] The Trigger frame may include information indicating that relay communication will be performed. That is, the AP 101 may use the Trigger frame to notify the end STA 111 and the relay STA 112 in advance that communication will be performed via relay communication, and then transmit a data frame addressed to the end STA 111. In this case, the Trigger frame may include information indicating that the STA 111 and the STA 112 should receive this Trigger frame. For example, the relay STA 112 and the end STA 111 may be indicated as the destinations of the Trigger frame. This allows the relay STA 112 and the end STA 111 to recognize that relay communication will be performed. Then, a data frame transmitted from the AP 101 after this Trigger frame may be received by the relay STA 112 and transmitted by the relay STA 112 to the end STA 111. Alternatively, the destination field of the Trigger frame may indicate the relay STA 112, and another field of the Trigger frame may indicate the end STA 111 as the destination of the data frame. In this case, the relay STA 112 may transmit another Trigger frame indicating that relay communication will be performed to the end STA 111 in response to receiving the Trigger frame. This may notify the end STA 111 that relay communication will be performed. In this case, the AP 101 may transmit a subsequent data frame based on the transmission of the Trigger frame from the relay STA 112. The relay STA 112 transmits the received data frame to the end STA 111. Note that the STA 112 does not need to transmit the Trigger frame to the end STA 111. In this case, the AP 101 transmits a data frame following the transmission of the Trigger frame addressed to the relay STA 112. The relay STA 112 may transmit the data frame received from the AP 101 to the end STA 111. This allows for more efficient use of wireless resources than when Trigger frames are transmitted separately from the AP 101 and the relay STA 112. Note that the Trigger frame may notify the frequency resources to be used in relay communication.For example, the Trigger frame may include information indicating the RU to be used when transmitting a data frame from the AP 101 to the relay STA 112, and information indicating the RU to be used when transmitting a data frame from the relay STA 112 to the end STA 111. When OFDMA communication is used, it becomes possible to flexibly select the RU to be used in each transmission. The frame used for notifying relay communication and reserving radio resources is not limited to the Trigger frame. For example, the AP 101 may transmit an RTS frame including a Duration field in which the period required for relay communication is set, and may reserve the period required for relay communication by receiving a CTS frame in response to this. In addition, the RTS frame may be used to notify information indicating that relay communication will be performed.

[0065] The AP 101 may also perform relay communication using a data frame formatted for relay communication without prior notification of the execution of relay communication using a trigger frame or the like. For example, the AP 101 may transmit a data frame addressed to the relay STA 112, including information indicating relay communication and information that can identify the end STA. The information indicating relay communication and the information that can identify the end STA may be included in the header of this data frame. In this case, upon receiving this data frame, the relay STA 112 may transmit a data frame of the same format with the destination changed to the end STA. The relay STA 112 may also generate and transmit a data frame in a format for direct communication using the received data frame. In this case, the destination of the data frame becomes the end STA 111, and the information indicating relay communication may be deleted. In these cases, the end STA 111 performs reception processing for the data frame addressed to itself. The AP 101 may also transmit a data frame for relay communication that includes information that can identify the relay STA and the end STA, and information indicating that the data frame is for relay communication. In this case, the relay STA 112 may transmit the received data frame to the end STA as is. The end STA can perform reception processing of the received data frame based on the information indicating that the data format is for relay communication.

[0066] On the other hand, if the AP 101 does not transmit a data frame (NO in S1107), it determines whether to receive data from the STA 111 (S1113). For example, the AP 101 may obtain the data storage status from all STAs 110 connected to the AP 101 and receive data frames from the STAs 110 that are storing data. As an example, the AP 101 may transmit a frame requesting a BSR to each STA 110. For example, the frame requesting a BSR may be a BSR Request frame. Alternatively, the frame requesting a BSR may be a BSR Poll frame. BSR is an abbreviation for Buffer Status Report. Upon receiving a BSR Request frame, the STA 110 may report to the AP 101 whether or not data is stored for each TID, and the amount of data. This allows the AP 101 to determine whether or not to receive data frames from each STA 110. The BSR Request frame and the response to this frame may be communicated via relay communication. If the AP 101 determines not to receive a data frame (NO in S1113), it may return to S1105 and repeat the process. On the other hand, if the AP 101 decides to receive data from the STA 111 (YES in S1113), it determines whether or not there is a candidate STA that can serve as a relay STA in communication with the STA 111 (S1114). If there is no candidate STA (NO in S1114), the AP 101 decides to communicate directly with the STA 111 (S1118). For example, the AP 101 may transmit a frame to cause the STA 111 to transmit a data frame. As an example, the AP 101 may transmit a Trigger frame to the STA 111. For example, the Trigger frame may include information indicating to the STA 111 that it should transmit a data frame directly to the AP 101. The information indicating that a data frame should be transmitted directly to the AP 101 may be, for example, information indicating that the destination of data transmitted by the STA 111 should be the AP 101. Furthermore, the information indicating that a data frame should be transmitted directly to the AP 101 may be information indicating that direct communication should be performed.On the other hand, if there is a candidate STA (YES in S1114), the AP 101 checks the communication quality between the AP 101 and the candidate STA and the communication quality between the candidate STA and STA 111. If the AP 101 determines that either communication quality is insufficient (NO in S1115), it decides to perform direct communication with STA 111 (S1118). If the AP 101 determines that both communication qualities are sufficient (YES in S1115), it determines whether to perform relay communication. For example, the AP 101 may determine whether to perform relay communication by determining whether the communication quality between itself and STA 111 is sufficient. If the AP 101 determines not to perform relay communication (NO in S1116), it may perform direct communication with STA 111 (S1118). If the AP 101 determines that the communication quality is insufficient, it may determine to perform relay communication (YES in S1116). In this case, the AP 101 may notify the STA 111 to transmit the data frame using relay communication (S1117).

[0067] The AP 101 may use a Trigger frame to notify the STA 111 to transmit a data frame using relay communication. As described above, the Trigger frame may reserve radio resources for relay communication and notify that relay communication should be performed. For example, the Duration field of the Trigger frame may be set to a period including a period for the end STA 111 to transmit a data frame to the relay STA 112 and a period for the relay STA 112 to transmit a data frame to the AP 101. The Duration field may also include a period for an ACK or BlockACK to be returned from the AP 101. In this case, the Duration field may be set to a period including, in addition to the above periods, a period for the AP 101 to transmit an ACK or the like to the relay STA 112 and a period for the relay STA 112 to transmit an ACK or the like to the end STA 111. The Duration field may be set to a period not limited to the above, and may be set to a period required for a procedure for performing relay communication, for example. The AP 101 may use the Trigger frame to instruct the end STA 111 and the relay STA 112 to transmit a data frame using relay communication. In this case, the Trigger frame may include information indicating that STA 111 and STA 112 should receive this Trigger frame and information indicating that a data frame should be transmitted by relay communication. For example, the relay STA 112 and the end STA 111 may be indicated as the destinations of the Trigger frame. This allows the relay STA 112 and the end STA 111 to recognize that relay communication should be performed. The end STA 111 may then transmit a data frame following this Trigger frame. The relay STA 112 may transmit the received data frame to the AP 101. Furthermore, the destination field of the Trigger frame may indicate the relay STA 112, and another field of the Trigger frame may indicate STA 111 as the end STA to which the data frame should be transmitted.In this case, in response to receiving this Trigger frame, the relay STA 112 may transmit another Trigger frame to the end STA 111, including information indicating that the data frame should be transmitted via relay communication. This allows the end STA 111 to recognize that transmission should be via relay communication. In this case, the end STA 111 may transmit a data frame to the AP 101 based on receiving the Trigger frame from the relay STA 112. The relay STA 112 transmits the received data frame to the AP 101. Note that the Trigger frame may include information indicating the RU to be used when transmitting a data frame from the end STA 111 to the relay STA 112 and information indicating the RU to be used when transmitting a data frame from the relay STA 112 to the AP 101. The AP 101 may transmit an RTS frame including a Duration field in which the period required for relay communication is set, and may receive a CTS frame in response to this, thereby securing the period required for relay communication. The RTS frame may also be used to notify information indicating that a data frame should be transmitted via relay communication.

[0068] (Processing flow in STA111) 12 shows an example of a processing flow when the STA 111 determines whether to perform relay communication. This processing may be the processing performed by the STA 111 in FIG. 1 when the STA 111 connects to the AP 101. For example, the STA 111 may execute this processing based on detecting the AP 101. Note that this processing may be executed repeatedly after the connection with the AP 101 is established. First, the STA 111 executes a connection process with the AP 101 (S1201). In the connection process, the STA 111 acquires capability information of the AP 101. For example, the STA 111 determines whether a UHR Capability element is included in a received Association Response frame or Probe Response frame (S1202). Note that the STA 111 may also determine whether a UHR Capability element is included in a Beacon received from the AP 101. If the UHR Capability element is not included (NO in S1202), the STA 111 determines that the AP 101 does not support the UHR function and may decide not to use relay communication in communicating data frames (S1206). That is, the STA 111 may communicate data frames directly with the AP 101. On the other hand, if the UHR Capability element is included (YES in S1202), the STA 111 acquires the values ​​of the Relay Transmit Capable field 604 and the Relay Receive Capable field 605. The determination of whether relay communication with the AP 101 is possible based on these fields is performed in the same manner as for the AP 101, and therefore a description thereof will be omitted. That is, the STA 111 determines whether relay communication is possible for each of the transmission and reception communication directions based on the capability information acquired from the AP 101 and its own capability information. The STA 111 then executes the process of S1206 for communication directions in which relay communication is not possible, and executes the process of S1204 and subsequent steps for communication directions in which relay communication is possible. If the value of at least one of the fields is 1 (YES in S1203), the STA 111 stores the AP 111 as having the relay communication function (S1204).

[0069] In the connection process, the STA 111 may notify the AP 101 of its own capability information. For example, the STA 111 may use a UHR Capability element to notify the AP 101 of the communication direction in which the STA 111 can perform relay communication. The STA 111 may also notify the AP 101 of its capability information that it can operate as a relay STA. For example, the STA 111 may use a UHR Operation element to notify the AP 101 of its capability information that it can operate as a relay STA.

[0070] The STA 111 determines whether or not relay communication can be used when communicating data frames with the AP 101 (S1205). Whether or not relay communication can be used can be switched, for example, by exchanging a Relay Mode Request frame and a Relay Mode Response frame between the AP 101 and the STA 111. If relay communication is disabled (NO in S1205), the STA 111 performs the process of S1206. If relay communication is enabled (YES in S1205), the STA 111 performs the process of S1107.

[0071] When the STA 111 transmits a data frame (YES in S1207), the STA 111 may notify the AP 101 that the STA 111 has stored data (S1208). For example, the STA 111 may perform the notification using a BSR frame or a BSR field included in a predetermined frame. The BSR field may be a BSR Control subfield. Based on this notification, the STA 111 may receive a frame transmitted from the AP 101 instructing the STA 111 to transmit. The instruction from the AP 101 may include information indicating whether the STA 111 should transmit the data frame directly to the AP 101 or should transmit it using relay communication. For example, this instruction may be made by a Trigger frame. When the STA 111 receives a Trigger frame including information indicating that the STA 111 should transmit the data frame directly to the AP 101 (NO in S1209), the STA 111 transmits the data frame directly to the AP 101 (S1211). This Trigger frame may be a Basic Trigger frame. Furthermore, when the STA 111 receives a Trigger frame including information indicating that a data frame should be transmitted using relay communication (YES in S1209), it transmits the data frame to the relay STA 112 (S1210). This Trigger frame may be an MU-RTX Trigger frame. Note that this Trigger frame may also be referred to as an MU-RTS Trigger frame. MU-RTS may be an abbreviation for Multiuser Request to send. The STA 111 may transmit a data frame to the AP 101 after an SIFS time has elapsed since receiving the Trigger frame indicating that a data frame should be transmitted using relay communication. SIFS may be an abbreviation for Short Inter Frame Space. This data frame may be transmitted to the AP 101 via the relay STA 112. Furthermore, the STA 111 may receive an ACK, BlockACK, or the like based on this data frame from the AP 101. These frame exchanges may be performed within a period secured by the Trigger frame transmitted by the AP 101. Note that the ACK and other messages transmitted from the AP 101 can be received directly by the STA 111.The method by which the end STA 111 transmits a data frame to the AP 101 via the relay STA 112 based on the Trigger frame can be the method described above in the description of S1017 of the processing flow in the AP 101.

[0072] Furthermore, if the STA 111 does not receive a Trigger frame indicating that a data frame should be transmitted within a predetermined period of time after transmitting a BSR frame, the STA 111 may transmit a data frame directly to the AP 101. The STA 111 may also autonomously perform relay communication without receiving instructions from the AP 101. In these cases, the STA 111 may transmit a Trigger frame before transmitting a data frame to ensure the period required for transmission and to notify the AP 101 that direct communication or relay communication will be performed. The STA 111 may also perform relay communication using a data frame formatted for relay communication without using a Trigger frame. The method by which the STA 111 transmits a data frame to the AP 101 using a Trigger frame or a data frame formatted for relay communication can be the same as the method described above in the description of S1111 in the processing flow for the AP 101. In this case, the AP 101 and the STA 111 can be interchangeable.

[0073] On the other hand, if STA 111 does not transmit a data frame (NO in S1207), it waits to receive a frame. If it does not receive a frame (NO in S1212), STA 111 returns to S1205 and continues processing. If it receives a frame (YES in S1212), STA 111 may perform reception processing based on the frame's sender. For example, if the frame's sender is AP 101 (YES in S1213), STA 111 analyzes the frame in frame analysis unit 406 as a proper data frame (S1216). Also, if the frame's sender matches a STA listed in the candidate STA list included in the Beacon (YES in S1214), STA 111 analyzes the frame in frame analysis unit 406 as a proper frame (S1216). In other cases (NO in S1213 and NO in S1214), STA 111 may discard the received frame (S1215).

[0074] (Performs some of the same functions as the AP in relay STA) The relay STA 112 may be configured to perform some of the same functions as the AP. For example, the STA 112 may periodically broadcast a beacon. The beacon broadcast by the STA 112 may be the same as the beacon broadcast by the AP 101. For example, when the STA 112 receives a beacon broadcast by the AP 101, the STA 112 may transmit the beacon after a predetermined time has elapsed. By broadcasting a beacon by the STA 112, the STA 110 that cannot receive a beacon from the AP 101 may be able to recognize the presence of the AP 101. The STA 112 may also perform connection processing with other STAs 110 instead of the AP 101. That is, the STA 112 may receive a probe request frame, an association request frame, a reassociation request frame, etc. from other STAs 110. In response to the received frames, the STA 112 may transmit a probe response frame, an association response frame, or a reassociation response frame. The STA 112 may have a function for performing connection processing with another STA 110 based on the capability information of the AP 101 acquired when establishing a connection with the AP 101. In this case, when the STA 112 establishes a connection with another STA 110, the STA 112 notifies the AP 101 of the capability information of the other STA 110. This allows the AP 101 to recognize that the other STA 110 has belonged to the BSS configured by the STA 112. Furthermore, the STA 112 does not have a function for performing connection processing with the other STA 110, but may relay the exchange of frames for connection processing between the AP 101 and the other STA 110. In this case, the AP 101 performs connection processing with the other STA 110 via relay by the STA 112, and therefore may recognize that the STA 110 has belonged to the BSS configured by the AP 101.

[0075] The Beacon broadcast by the STA 112 may be partially different from the Beacon broadcast by the AP 101. When the STA 112 receives a Beacon broadcast from the AP 101, the STA 112 may modify a portion of the Beacon and transmit the Beacon after a predetermined time has elapsed. For example, the STA 112 may broadcast a Beacon that does not include information about candidate STAs. As an example, the STA 112 may broadcast a Beacon that includes a UHR Operation element that does not include a Relay STA List field 705. In this case, the Beacon may include information that can identify the STA 112 and a Relayed AP address field 706 that includes the MAC address and BSSID of the AP 101 to which the STA 112 belongs. With this information, other STAs 110 may identify that the STA 112 transmitting the Beacon is a relay STA and will perform relaying between the STA 112 and the AP 101. This eliminates the need for information about candidate STAs in the Beacon broadcast by the STA 112. For example, by broadcasting Operation parameters that the STA 112 can use via a Beacon, the information to be included in the STA Info in Fig. 7 can be notified. Note that the Relayed AP address field 706 transmitted by the STA 112 can be encrypted before transmission. This can avoid the risk of spoofing, where a malicious STA pretends to belong to the AP 101 and is relaying data.

[0076] As described above, according to this embodiment, when a predetermined condition is satisfied, relay communication with an end STA is performed via a relay STA. The predetermined condition may be that the AP and the end STA have the capability to perform relay communication. Therefore, the AP may obtain information indicating that the end STA has the capability to perform relay communication from the end STA. Furthermore, the AP may notify information indicating that the end STA has the capability to perform relay communication. This configuration allows each communication device to recognize that other communication devices can perform relay communication. This enables relay communication via a relay STA to be used when a specific end STA is located far from the AP and the communication quality is poor, thereby enabling wireless access services provided by the AP to be provided stably over a wider area. Note that in the above description, an example was given in which the UHR Capability element is used to indicate capability information indicating that the AP, relay STA, or end STA can perform relay communication. However, the element for indicating the capability information is not limited to this, and other elements may be used. For example, Extended Capability may be used. This enables general capability information to be notified to the other device. Note that the names of the above-described elements and fields are merely examples and may be referred to by other names. Furthermore, the names relay communication, relay STA, end STA, etc. are merely examples, and other names may be used.

[0077] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0078] (Summary of the embodiment) At least some of the above-described embodiments can be summarized as follows. (Item 1) A communication device capable of operating as an access point conforming to the IEEE 802.11 series standard, a communication means capable of executing a first communication method for performing communication via another station device that relays data frames and a second communication method for performing direct communication in communication between the communication device and a station device; an acquisition means for acquiring, from the station device, first capability information indicating that the station device has a first capability for executing the first communication method; a selection means for selecting either the first communication method or the second communication method as a communication method to be used in communication with the station device when the station device has the first capability, and for selecting the second communication method when the station device does not have the first capability; The communication means communicates with the station device based on the result of the selection. A communication device comprising: (Item 2) the first capability information is information indicating that communication using frames of a first format used in the first communication method, the first format being different from a second format used in the second communication method, is executable; When the communication means communicates with the station device using the first communication method, the communication means communicates using frames in the first format. 2. The communication device according to item 1, (Item 3) The frame of the first format is a Trigger frame including information indicating that radio resources for communication using the first communication method are reserved and that communication will be performed using the first communication method. 3. The communication device according to item 2. (Item 4) The first capability information is information indicating that at least one of transmission and reception using frames in the first format can be performed. 4. The communication device according to item 2 or 3. (Item 5) The acquisition means acquires the first capability information using at least one of a Probe Request frame, an Association Request frame, and a Reassociation Request frame. 5. The communication device according to any one of items 1 to 4, (Item 6) The communication device further includes a first notification means for notifying second capability information indicating that the communication device has a second capability for executing the first communication method. 6. A communication device according to items 1 to 5. (Item 7) The first notification means notifies the second capability information using at least one of a Beacon frame, a Probe Response frame, an Association Response frame, and a Reassociation Response frame. 7. The communication device according to item 6, (Item 8) The station device further includes a second notification means for notifying the first identification information that can identify the other station device. 8. The communication device according to any one of items 1 to 7, (Item 9) The first identification information is information that can identify the MAC address of the other station device. 9. The communication device according to item 8, (Item 10) The second notification means further notifies second identification information capable of identifying the operation parameters of the other station device. 10. The communication device according to item 8 or 9, (Item 11) a receiving means for receiving a request not to use the first communication method from the station device; The communication means communicates with the station device using the second communication method without using the first communication method based on the request. 2. The communication device according to item 1, (Item 12) The receiving means receives the request using an Action frame. Item 12. A communication device according to item 11. (Item 13) A communication device capable of operating as a station conforming to the IEEE 802.11 series standard, a communication means capable of executing a first communication method for performing communication via another station device that relays data frames and a second communication method for performing direct communication in communication between the communication device and an access point; a notification means for notifying an access point of first capability information indicating that the communication device has a first capability for executing the first communication method, a communication method to be used in communication between the access point and the communication device is selected when the communication device has the first capability, either the first communication method or the second communication method, and when the station device does not have the first capability, the second communication method is selected; The communication means communicates with the access point based on the result of the selection. A communication device comprising: (Item 14) the first capability information is information indicating that communication using frames of a first format used in the first communication method, the first format being different from a second format used in the second communication method, is executable; When the communication means communicates with the station device using the first communication method, the communication means communicates using frames in the first format. Item 14. The communication device according to item 13. (Item 15) The frame of the first format is a Trigger frame including information indicating that radio resources for communication using the first communication method are reserved and that communication will be performed using the first communication method. Item 15. A communication device according to item 14. (Item 16) The first capability information is information indicating that at least one of transmission and reception using frames in the first format can be performed. 16. The communication device according to item 14 or 15. (Item 17) The notification means notifies the first capability information by using at least one of a Probe Request frame, an Association Request frame, and a Reassociation Request frame. 17. The communication device according to any one of items 13 to 16, (Item 18) The access point further includes a first acquiring means for acquiring second capability information indicating that the access point has a second capability for performing the first communication method. 18. A communication device according to any one of items 13 to 17. (Item 19) The notification means performs the notification when the access point has the second capability. Item 19. A communication device according to item 18, characterized in that (Item 20) The first acquisition means acquires the second capability information using at least one of a Beacon frame, a Probe Response frame, an Association Response frame, and a Reassociation Response frame transmitted from the access point or the other station device. 20. The communication device according to item 18 or 19, (Item 21) The station device further includes a second acquisition unit for acquiring first identification information that can identify the other station device. 21. A communication device according to any one of items 13 to 20. (Item 22) The first identification information is information that can identify the MAC address of the other station device. 22. The communication device according to item 21, (Item 23) The second acquisition means further acquires second identification information capable of identifying the operating parameters of the other station device. 23. The communication device according to item 21 or 22. (Item 24) The second acquisition means acquires the first identification information using at least one of a Beacon frame, a Probe Response frame, an Association Response frame, and a Reassociation Response frame transmitted from the access point or the other station device. 24. The communication device according to any one of items 21 to 23, (Item 25) The method further includes requesting means for requesting the access point not to use the first communication method. Item 14. The communication device according to item 13. (Item 26) The requesting means makes the request using an Action frame. 26. The communication device according to item 25, (Item 27) A communication device capable of operating as a station conforming to the IEEE 802.11 series standard, a relay means capable of relaying data frames as a relay device when a communication is performed using a predetermined communication method via the relay device in a communication between an access point and another station device; a notification means for notifying the access point of capability information indicating that the access point has a predetermined capability for performing the relaying; In communication between the access point and another station device, a determination is made as to whether or not to use the communication device as the relay device based on the capability information; The relay means performs the relay in the communication between the access point and another station device based on the result of the determination. A communication device comprising: (Item 28) the predetermined capability includes being able to perform communication using frames of a predetermined format used in the predetermined communication method; The relay means performs the relay using frames in the predetermined format. 28. The communication device according to item 27, (Item 29) The frame of the predetermined format is a Trigger frame including information indicating that radio resources for communication using the predetermined communication method are reserved and that communication is to be performed using the predetermined communication method. 29. The communication device according to item 28, (Item 30) The capability information is information indicating that the access point can execute predetermined functions that are at least part of the functions executed by the access point. 30. A communication device according to any one of items 27 to 29. (Item 31) The predetermined function is to transmit a beacon. 31. The communication device according to item 30, (Item 32) The beacon includes information that can identify the access point. 32. The communication device according to item 31, (Item 33) The predetermined function is to perform connection processing for the other station device to connect to the access point. 31. The communication device according to item 30, (Item 34) The notification means notifies the capability information using at least one of a Probe Request frame, an Association Request frame, and a Reassociation Request frame. 34. A communication device according to any one of items 27 to 33, characterized in that (Item 35) A control method executed by a communication device operable as an access point conforming to the IEEE 802.11 series standards, comprising: a communication step capable of executing a first communication method for performing communication via another station device that relays data frames and a second communication method for performing direct communication in communication between the communication device and a station device; an acquiring step of acquiring first capability information from the station device, the first capability information indicating that the station device has a first capability for performing the first communication method; a selection step of selecting either the first communication method or the second communication method as a communication method to be used in communication with the station device when the station device has the first capability, and selecting the second communication method when the station device does not have the first capability; Based on the result of the selection, communication with the station device is performed. A control method comprising: (Item 36) A control method executed by a communication device operable as a station conforming to the IEEE 802.11 series standards, comprising: a communication step capable of executing a first communication method for performing communication via another station device that relays data frames and a second communication method for performing direct communication in communication between the communication device and an access point; a notification step of notifying an access point of first capability information indicating that the communication device has a first capability for executing the first communication method, a communication method to be used in communication between the access point and the communication device is selected when the communication device has the first capability, either the first communication method or the second communication method, and when the station device does not have the first capability, the second communication method is selected; Based on the result of the selection, communication with the access point is performed. A control method comprising: (Item 37) A control method executed by a communication device operable as a station conforming to the IEEE 802.11 series standards, comprising: a relay step of, when communication is performed between an access point and another station device using a predetermined communication method via a relay device that relays data frames, being capable of performing the relay as the relay device; a notification step of notifying the access point of capability information indicating that the access point has a predetermined capability for performing the relay. In communication between the access point and another station device, a determination is made as to whether or not to use the communication device as the relay device based on the capability information; Based on the result of the determination, the relay of the communication between the access point and another station device is performed. A control method comprising: (Item 38) A program for causing a computer to function as each of the means possessed by the communication device described in any one of items 1 to 34.

[0079] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0080] 101:AP, 111:STA, 112:STA

Claims

1. A communication device capable of operating as an access point conforming to the IEEE 802.11 series standard, a communication means capable of executing a first communication method for performing communication via another station device that relays data frames and a second communication method for performing direct communication in communication between the communication device and a station device; an acquisition means for acquiring, from the station device, first capability information indicating that the station device has a first capability for executing the first communication method; a selection means for selecting either the first communication method or the second communication method as a communication method to be used in communication with the station device when the station device has the first capability, and for selecting the second communication method when the station device does not have the first capability; The communication means communicates with the station device based on the result of the selection. A communication device comprising:

2. the first capability information is information indicating that communication using frames of a first format used in the first communication method, the first format being different from a second format used in the second communication method, is executable; When the communication means communicates with the station device using the first communication method, the communication means communicates using frames in the first format.

2. The communication device according to claim 1.

3. The frame of the first format is a Trigger frame that reserves radio resources for communication using the first communication method and includes information indicating that communication will be performed using the first communication method.

3. The communication device according to claim 2.

4. The first capability information is information indicating that at least one of transmission and reception using frames in the first format can be performed.

3. The communication device according to claim 2.

5. The acquisition means acquires the first capability information using at least one of a Probe Request frame, an Association Request frame, and a Reassociation Request frame.

2. The communication device according to claim 1.

6. The communication device further includes a first notification means for notifying second capability information indicating that the communication device has a second capability for executing the first communication method.

6. A communication device according to claim 1, wherein:

7. The first notification means notifies the second capability information using at least one of a Beacon frame, a Probe Response frame, an Association Response frame, and a Reassociation Response frame.

7. The communication device according to claim 6.

8. The station device further includes a second notification means for notifying the first identification information that can identify the other station device.

2. The communication device according to claim 1.

9. The first identification information is information that can identify the MAC address of the other station device.

9. The communication device according to claim 8.

10. The second notification means further notifies second identification information that can identify the operating parameters of the other station device.

9. The communication device according to claim 8.

11. a receiving means for receiving a request not to use the first communication method from the station device; The communication means communicates with the station device using the second communication method without using the first communication method based on the request.

2. The communication device according to claim 1.

12. The receiving means receives the request using an Action frame.

12. The communication device according to claim 11.

13. A communication device capable of operating as a station conforming to the IEEE 802.11 series standard, a communication means capable of executing a first communication method for performing communication via another station device that relays data frames and a second communication method for performing direct communication in communication between the communication device and an access point; notification means for notifying an access point of first capability information indicating that the communication device has a first capability for executing the first communication method; a communication method to be used in communication between the access point and the communication device is selected when the communication device has the first capability, either the first communication method or the second communication method, and when the station device does not have the first capability, the second communication method is selected; The communication means communicates with the access point based on the result of the selection. A communication device comprising:

14. the first capability information is information indicating that communication using frames of a first format used in the first communication method, the first format being different from a second format used in the second communication method, is executable; When the communication means communicates with the station device using the first communication method, the communication means communicates using frames in the first format.

14. The communication device according to claim 13.

15. The frame of the first format is a Trigger frame that reserves radio resources for communication using the first communication method and includes information indicating that communication will be performed using the first communication method.

15. The communication device according to claim 14.

16. The first capability information is information indicating that at least one of transmission and reception using frames in the first format can be performed.

15. The communication device according to claim 14.

17. The notification means notifies the first capability information using at least one of a Probe Request frame, an Association Request frame, and a Reassociation Request frame.

14. The communication device according to claim 13.

18. The access point further includes a first acquiring means for acquiring second capability information indicating that the access point has a second capability for executing the first communication method.

14. The communication device according to claim 13.

19. The notification means performs the notification when the access point has the second capability.

20. The communication device according to claim 18,

20. The first acquisition means acquires the second capability information using at least one of a Beacon frame, a Probe Response frame, an Association Response frame, and a Reassociation Response frame transmitted from the access point or the other station device.

20. The communication device according to claim 18,

21. The station device further includes a second acquisition unit for acquiring first identification information that can identify the other station device.

14. The communication device according to claim 13.

22. The first identification information is information that can identify the MAC address of the other station device.

22. The communication device according to claim 21 .

23. The second acquisition means further acquires second identification information capable of identifying the operating parameters of the other station device.

22. The communication device according to claim 21 .

24. The second acquisition means acquires the first identification information using at least one of a Beacon frame, a Probe Response frame, an Association Response frame, and a Reassociation Response frame transmitted from the access point or the other station device.

22. The communication device according to claim 21 .

25. The method further includes requesting means for requesting the access point not to use the first communication method.

14. The communication device according to claim 13.

26. The requesting means makes the request using an Action frame.

26. The communication device of claim 25.

27. A communication device capable of operating as a station conforming to the IEEE 802.11 series standard, a relay means capable of relaying data frames as a relay device when a communication is performed using a predetermined communication method via the relay device in a communication between an access point and another station device; a notification means for notifying the access point of capability information indicating that the access point has a predetermined capability for performing the relaying; In communication between the access point and another station device, a determination is made as to whether or not to use the communication device as the relay device based on the capability information; The relay means performs the relay in the communication between the access point and another station device based on the result of the determination. A communication device comprising:

28. the predetermined capability includes being able to perform communication using frames of a predetermined format used in the predetermined communication method; The relay means performs the relay using frames in the predetermined format.

28. The communication device of claim 27.

29. The frame of the predetermined format is a Trigger frame including information indicating that radio resources for communication using the predetermined communication method are reserved and that communication will be performed using the predetermined communication method.

29. The communication device of claim 28.

30. The capability information is information indicating that the access point can execute predetermined functions that are at least part of the functions executed by the access point.

28. The communication device of claim 27.

31. The predetermined function is to transmit a beacon.

31. The communication device of claim 30.

32. The beacon includes information that can identify the access point.

32. The communication device of claim 31 .

33. The predetermined function is to perform connection processing for the other station device to connect to the access point.

31. The communication device of claim 30.

34. The notification means notifies the capability information using at least one of a Probe Request frame, an Association Request frame, and a Reassociation Request frame.

28. The communication device of claim 27.

35. A control method executed by a communication device operable as an access point conforming to the IEEE 802.11 series standards, comprising: a communication step for executing a first communication method for performing communication via another station device that relays data frames and a second communication method for performing direct communication between the communication device and a station device; an acquiring step of acquiring, from the station device, first capability information indicating that the station device has a first capability for performing the first communication method; a selection step of selecting either the first communication method or the second communication method as a communication method to be used in communication with the station device when the station device has the first capability, and selecting the second communication method when the station device does not have the first capability; Based on the result of the selection, communication with the station device is performed. A control method comprising:

36. A control method executed by a communication device operable as a station conforming to the IEEE 802.11 series standard, comprising: a communication step capable of executing a first communication method for performing communication via another station device that relays data frames and a second communication method for performing direct communication in communication between the communication device and an access point; a notification step of notifying an access point of first capability information indicating that the communication device has a first capability for executing the first communication method, a communication method to be used in communication between the access point and the communication device is selected when the communication device has the first capability, either the first communication method or the second communication method, and when the station device does not have the first capability, the second communication method is selected; Based on the result of the selection, communication with the access point is performed. A control method comprising:

37. A control method executed by a communication device operable as a station conforming to the IEEE 802.11 series standard, comprising: a relay step of, when communication is performed between an access point and another station device using a predetermined communication method via a relay device that relays data frames, being capable of performing the relay as the relay device; a notification step of notifying the access point of capability information indicating that the access point has a predetermined capability for performing the relay. In communication between the access point and another station device, a determination is made as to whether or not to use the communication device as the relay device based on the capability information; Based on the result of the determination, the relay of the communication between the access point and another station device is performed. A control method comprising:

38. A program for causing a computer to function as each of the means included in the communication device according to claim 1.

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