First terminal device and wireless communication method

Abstract

To provide a wireless communication device, a wireless terminal device, and a wireless communication method that perform intra-BSS SR on data used by applications that are designated as high-priority traffic and low latency, and improve communication efficiency in cooperation with the applications.SOLUTION: In a method, a base station device AP that communicates with a terminal device STA receives configuration information for direct communication, generates SR link information that includes a color index linked to the terminal device that performs direct communication and a power detection level applied to combinations that perform direct communication if intra-BSS Spatial Reuse (SR) is enabled, and notifies the terminal device. When the radio wave propagation state of the terminal device changes, information identifying the terminal device and information about the power detection level are transmitted to the base station device.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present invention relates to a wireless communication device, a wireless terminal device, and a wireless communication method. [Background technology]

[0002] The Institute of Electrical and Electronics Engineers Inc. (IEEE) is continuously working on updating the specifications of IEEE802.11, the standard for wireless LAN (Local Area Network), to realize faster wireless LAN (Local Area Network) communication and more efficient frequency utilization. Wireless LAN can perform wireless communication using unlicensed bands that can be used without permission (license) from a country or region. For personal use such as at home, wireless LAN access from within the home has been made wireless by including a wireless LAN access point function in a line termination device for connecting to a WAN (Wide Area Network) line to the Internet, or by connecting a wireless LAN access point device (AP) to the line termination device. In other words, wireless LAN station devices (STAs) such as smartphones and PCs can connect to a wireless LAN access point device and access the Internet.

[0003] The IEEE802.11ax specification was completed in February 2021, and wireless LAN devices that comply with the specification, as well as communication devices such as smartphones and PCs (Personal Computers) equipped with the wireless LAN devices, have appeared on the market as Wi-Fi6 (registered trademark, the name for IEEE802.11ax-compliant products certified by the Wi-Fi Alliance). Currently, standardization activities for IEEE802.11be have begun as the successor to IEEE802.11ax. With the rapid spread of wireless LAN devices, the IEEE802.11be standardization is considering further improving throughput per user in environments where wireless LAN devices are densely deployed.

[0004] In the IEEE802.11n and later standards, a frame aggregation mechanism has been introduced as a technology to increase throughput by reducing overhead. Frame aggregation is broadly divided into A-MSDU (Aggregated MAC Service Data Unit) and A-MPDU (Aggregated MAC Protocol Data Unit). Frame aggregation allows a large amount of data to be transmitted at once, improving transmission efficiency, but it also increases the possibility of transmission errors. For this reason, in the IEEE802.11ax and later standards, in addition to improving transmission efficiency through frame aggregation, efficient error control for each MPDU is expected to be introduced as a key element technology for increasing throughput. In addition, mechanisms to increase TXOP (Transmit Opportunity), such as OFDMA (Orthogonal Frequency Division Multiple Access) and inter-BSS spatial reuse, are being adopted, and it is expected that transmission efficiency will be improved. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] IEEE 802.11-20 / 1046-08-0be, July.2020 Summary of the Invention [Problem to be solved by the invention]

[0006] As wireless LAN devices become more widespread, the areas where wireless LAN devices are used are expanding in urban areas, and in some places, double-digit numbers of wireless LAN devices are in use in the vicinity. If traffic increases in such a congested environment, when wireless medium access based on CSMA (Carrier Sense Multiple Access) used in the IEEE802.11 specification is used, the transmission efficiency decreases because the time that TXOP can be secured decreases due to collisions and the occurrence of exposed terminals. The IEEE802.11ax standard adopts Inter-BSS spatial reuse technology to partially alleviate this problem, but it is not sufficient.

[0007] The present invention has been made in consideration of the above circumstances, and discloses a communication device and a communication method that increase the opportunities to secure TXOP by realizing spatial reuse operation within the same wireless system (BSS), thereby improving transmission efficiency and reducing latency. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, a communication device and a communication method according to the present invention are as follows.

[0009] (1) That is, a wireless communication device according to one embodiment of the present invention includes a receiving unit that receives received frames and a transmitting unit that transmits transmitted frames, and receives first information from a first wireless terminal device that approves a direct communication setting with a second wireless terminal device, and if the first information includes information that intra-BSS SR is enabled, generates SR link information including information indicating the first wireless terminal device, information indicating the second wireless terminal device, a color index linked to the information indicating the first wireless terminal device and the information indicating the second wireless terminal device, and information on a power detection level to be applied to a combination of the first wireless terminal device and the second wireless terminal device.

[0010] (2) Furthermore, a wireless communication device according to an embodiment of the present invention generates the SR link information and then transmits the SR link information to one or more wireless terminal devices.

[0011] (3) Furthermore, when a wireless communication device according to one embodiment of the present invention receives information from the first wireless terminal device to release direct communication with the second wireless terminal device, the wireless communication device deletes from the SR link information a color index linked to the information indicating the first wireless terminal device and the information indicating the second wireless terminal device, the information indicating the first wireless terminal device corresponding to the color index, the information indicating the second wireless terminal device, and the information on the power detection level.

[0012] (4) In addition, in a wireless communication device according to one embodiment of the present invention, the receiving unit receives an association request, and the transmitting unit transmits an association response corresponding to the received association request, and the association response includes capability information including information that intra-BSS SR is valid.

[0013] (5) Furthermore, a wireless terminal device according to one embodiment of the present invention includes a transmitting unit that transmits a transmission frame and a receiving unit that receives a reception frame, and transmits information that intra-BSS SR is enabled to a wireless communication device and receives SR link information from the wireless communication device, the SR link information including at least information indicating a second wireless terminal device, information indicating a third wireless terminal device, a color index linked to the information indicating the second wireless terminal device and the information indicating the third wireless terminal device, and information on a power detection level applied to a combination of the first wireless terminal device and the second wireless terminal device.

[0014] (6) Furthermore, a wireless terminal device according to one embodiment of the present invention transmits a direct communication setting request to a fourth wireless terminal device, transmits a direct communication setting approval to the fourth wireless terminal device, and includes information indicating that intra-BSS SR is valid in the direct communication setting approval.

[0015] (7) Furthermore, in a wireless terminal device according to one embodiment of the present invention, the transmitting unit transmits an association request to the wireless communication device, and the association request includes capability information, and when the capability information includes information indicating that intra-BSS SR is enabled, the capability information includes information indicating that direct communication is enabled.

[0016] (8) Furthermore, a wireless terminal device according to one embodiment of the present invention transmits a direct communication discovery request to a fifth wireless terminal device via the wireless communication device, receives a direct communication discovery response directly from the fifth wireless terminal device, the direct communication discovery request includes information indicating that intra-BSS SR is valid, and the direct communication discovery response includes information indicating that intra-BSS SR is valid.

[0017] (9) Furthermore, when a wireless terminal device according to one embodiment of the present invention communicates directly with a sixth wireless terminal device, it transmits information identifying the sixth wireless terminal device and information on a power detection level to the wireless communication device.

[0018] (10) Furthermore, a wireless communication method according to one embodiment of the present invention receives, from a first wireless terminal device, first information approving a direct communication setting with a second wireless terminal device, and if the first information includes information that intra-BSS SR is enabled, generates SR link information including information indicating the first wireless terminal device, information indicating the second wireless terminal device, a color index linked to the information indicating the first wireless terminal device and the information indicating the second wireless terminal device, and information on a power detection level to be applied to a combination of the first wireless terminal device and the second wireless terminal device.

[0019] (11) Furthermore, a wireless communication method according to one embodiment of the present invention includes transmitting information indicating that intra-BSS SR is enabled to a wireless communication device, and receiving SR link information from the wireless communication device, the SR link information including at least information indicating a second wireless terminal device, information indicating a third wireless terminal device, a color index linked to the information indicating the second wireless terminal device and the information indicating the third wireless terminal device, and information on a power detection level applied to a combination of a first wireless terminal device and the second wireless terminal device. Effect of the Invention

[0020] The present invention can contribute to improving communication efficiency in communication using a wireless communication device conforming to the IEEE802.11 standard. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 is a schematic diagram illustrating an example of division of radio resources according to an aspect of the present invention. [Diagram 2] FIG. 2 is a diagram illustrating an example of a frame configuration according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a diagram illustrating an example of a frame configuration according to an embodiment of the present invention. [Figure 4] FIG. 2 is a diagram illustrating an example of communication according to an embodiment of the present invention. [Diagram 5] FIG. 1 is a diagram illustrating an example of a configuration of a communication system according to an aspect of the present invention. [Figure 6] 1 is a block diagram showing an example of a configuration of a wireless communication device according to an aspect of the present invention. [Figure 7] 1 is a block diagram showing an example of a configuration of a wireless communication device according to an aspect of the present invention. [Figure 8] FIG. 2 is a schematic diagram of a radio frame transmission according to one aspect of the present invention. [Figure 9] FIG. 2 is a schematic diagram illustrating an example of a frame format according to an embodiment of the present invention. [Figure 10] 1 is a diagram illustrating an example of the configuration of a base station device and a terminal device according to an embodiment of the present invention. [Figure 11]1 is a diagram illustrating an example of the configuration of a base station device and a terminal device according to an embodiment of the present invention. [Figure 12] FIG. 2 is a diagram illustrating an example of a message flow between wireless communication devices according to an embodiment of the present invention. [Figure 13] FIG. 2 is a diagram illustrating an example of a message flow between wireless communication devices according to an embodiment of the present invention. [Figure 14] FIG. 1 is a diagram illustrating an example of power detection levels and transmission power according to an embodiment of the present invention. [Figure 15] FIG. 1 is a diagram showing an example of an information element according to one aspect of the present invention. [Figure 16] FIG. 2 is a diagram illustrating an example of a message flow between wireless communication devices according to an embodiment of the present invention. [Figure 17] FIG. 2 is a diagram showing transmission and reception timing according to one embodiment of the present invention. [Figure 18] FIG. 2 is a diagram showing transmission and reception timing according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The communication system in this embodiment includes an access point device (also referred to as a base station device) and a plurality of station devices (or terminal devices, wireless terminal devices). A communication system or network configured with the access point device and the station devices is called a basic service set (BSS: Basic service set, management range, cell). The station device according to this embodiment can have the functions of an access point device. Similarly, the access point device according to this embodiment can have the functions of a station device (also referred to as a terminal device). Therefore, hereinafter, when simply referring to a communication device or a wireless communication device, the communication device or the wireless communication device can indicate both a station device and an access point device. The access point device may communicate with other access point devices.

[0023] The base station device and the terminal device in the BSS communicate with each other based on CSMA / CA (Carrier sense multiple access with collision avoidance). In this embodiment, the base station device communicates with a plurality of terminal devices in the infrastructure mode, but the method of this embodiment can also be implemented in the ad-hoc mode in which the terminal devices communicate directly with each other. In the ad-hoc mode, the terminal devices form a BSS in place of the base station device. The BSS in the ad-hoc mode is also called an IBSS (Independent Basic Service Set). In the following, the terminal devices forming the IBSS in the ad-hoc mode can also be considered as the base station device. The method of this embodiment can also be implemented in P2P (Peer to Peer) communication in which the terminal devices communicate directly with each other. One of the methods for implementing P2P communication is TDLS (Tunneled Direct Link Setup). In TDLS, traffic flowing between the terminal devices connected to the base station device is transmitted and received directly between the terminal devices without passing through the base station device. The method of this embodiment can also be implemented in Wi-Fi Direct (registered trademark). In Wi-Fi Direct, a terminal device forms a group instead of a base station device. In the following, a terminal device that is a group owner that forms a group in Wi-Fi Direct can also be considered as a base station device.

[0024] In the IEEE802.11 system, each device can transmit frames of multiple frame types that have a common frame format. The transmission frames are defined in the physical (PHY) layer, the medium access control (MAC) layer, and the logical link control (LLC) layer. The physical layer is also called the PHY layer, and the MAC layer is also called the MAC layer.

[0025] The transmission frame of the PHY layer is called a physical protocol data unit (PPDU, physical layer frame). The PPDU is composed of a physical layer header (PHY header) that contains header information for signal processing in the physical layer, and a physical service data unit (PSDU, MAC layer frame), which is a data unit processed in the physical layer. The PSDU can be composed of an aggregated MPDU (A-MPDU), which aggregates multiple MAC protocol data units (MPDUs), which are the units of retransmission in the wireless section.

[0026] The PHY header includes reference signals such as a short training field (STF) used for signal detection and synchronization, a long training field (LTF) used to acquire channel information for data demodulation, and control signals such as a signal (SIG) containing control information for data demodulation. STFs are classified into legacy STF (L-STF), high throughput STF (HT-STF), very high throughput STF (VHT-STF), high efficiency STF (HE-STF), and extremely high throughput STF (EHT-STF), depending on the corresponding standard, and LTFs and SIGs are similarly classified into L-LTF, HT-LTF, VHT-LTF, HE-LTF, L-SIG, HT-SIG, VHT-SIG, HE-SIG, and EHT-SIG. VHT-SIG is further classified into VHT-SIG-A1, VHT-SIG-A2, and VHT-SIG-B. Similarly, HE-SIG is classified into HE-SIG-A1 to HE-SIG-A4 and HE-SIG-B. In addition, it can include a Universal SIGNAL (U-SIG) field that contains additional control information in anticipation of technical updates in the same standard.

[0027] Furthermore, the PHY header can include information for identifying the BSS that is the source of the transmission frame (hereinafter, also referred to as BSS identification information). The information for identifying the BSS can be, for example, the SSID (Service Set Identifier) ​​of the BSS or the MAC address of the base station device of the BSS. The information for identifying the BSS can also be a value unique to the BSS (for example, BSS Color, etc.) other than the SSID or MAC address.

[0028] The PPDU is modulated according to a corresponding standard, for example, in the case of the IEEE802.11n standard, it is modulated into an Orthogonal Frequency Division Multiplexing (OFDM) signal.

[0029] MPDU is composed of a MAC layer header (MAC header) that contains header information for signal processing at the MAC layer, a MAC service data unit (MSDU) or frame body that is a data unit processed at the MAC layer, and a frame check sequence (FCS) that checks whether there are any errors in the frame. In addition, multiple MSDUs can be aggregated as an aggregated MSDU (A-MSDU).

[0030] The frame types of MAC layer transmission frames are broadly classified into three types: management frames that manage the connection status between devices, control frames that manage the communication status between devices, and data frames that contain the actual transmission data. Each type is further classified into multiple subframe types. Control frames include acknowledgement (Ack) frames, request to send (RTS) frames, and clear to send (CTS) frames. Management frames include beacon frames, probe request frames, probe response frames, authentication frames, association request frames, and association response frames. Data frames include data frames and polling (CF-poll) frames. Each device can determine the frame type and subframe type of the received frame by reading the contents of the frame control field included in the MAC header.

[0031] The Ack may include a Block Ack. The Block Ack can be used to notify a plurality of MPDUs of completion of reception. The Ack may also include a Multi-STA Block Ack (M-BA) that includes a reception completion notification for a plurality of communication devices.

[0032] The beacon frame includes a field that describes the period (Beacon interval) at which the beacon is transmitted and the SSID. The base station device can periodically broadcast the beacon frame within the BSS, and the terminal device can identify the base station devices around the terminal device by receiving the beacon frame. The terminal device's identification of the base station device based on the beacon frame broadcast by the base station device is called passive scanning. On the other hand, the terminal device's exploration of the base station device by broadcasting a probe request frame within the BSS is called active scanning. The base station device can transmit a probe response frame in response to the probe request frame, and the contents of the probe response frame are equivalent to those of the beacon frame.

[0033] After recognizing a base station device, the terminal device performs a connection process with the base station device. The connection process is classified into an authentication procedure and an association procedure. The terminal device transmits an authentication frame (authentication request) to the base station device to which it wishes to connect. When the base station device receives the authentication frame, it transmits an authentication frame (authentication response) to the terminal device that includes a status code indicating whether the terminal device has been authenticated or not. By reading the status code written in the authentication frame, the terminal device can determine whether or not it has been authorized to be authenticated by the base station device. Note that the base station device and the terminal device can exchange authentication frames multiple times.

[0034] Following the authentication procedure, the terminal device transmits a connection request frame to the base station device to perform a connection procedure. When the base station device receives the connection request frame, it determines whether or not to permit the connection of the terminal device, and transmits a connection response frame to notify the result. The connection response frame contains a status code indicating whether or not the connection process is possible, as well as an association identifier (AID) for identifying the terminal device. The base station device can manage multiple terminal devices by setting different AIDs for each terminal device for which it has issued connection permission.

[0035] After the connection process is performed, the base station device and the terminal device perform actual data transmission. In the IEEE802.11 system, a distributed coordination function (DCF), a point coordination function (PCF), and their extended functions (enhanced distributed channel access (EDCA) and hybrid coordination function (HCF), etc.) are defined. In the following, a case where a base station device transmits a signal to a terminal device using DCF will be described as an example, but the same applies when a terminal device transmits a signal to a base station device using DCF.

[0036] In DCF, a base station device and a terminal device perform carrier sense (CS) to check the usage status of a wireless channel around the device before communication. For example, when a base station device, which is a transmitting station, receives a signal higher than a predetermined clear channel assessment level (CCA level) on the wireless channel, it postpones the transmission of a transmission frame on the wireless channel. Hereinafter, a state in which a signal of CCA level or higher is detected on the wireless channel is called a busy state, and a state in which a signal of CCA level or higher is not detected is called an idle state. In this way, CS performed by each device based on the power of a signal actually received (received power level) is called physical carrier sense (physical CS). The CCA level is also called a carrier sense level (CS level) or a CCA threshold (CCA threshold: CCAT). When a signal of CCA level or higher is detected, the base station device and the terminal device start an operation of demodulating at least a PHY layer signal.

[0037] The base station device performs carrier sensing for an inter frame space (IFS) that corresponds to the type of transmission frame to be transmitted, and judges whether the wireless channel is busy or idle. The period during which the base station device performs carrier sensing varies depending on the frame type and subframe type of the transmission frame that the base station device is about to transmit. In the IEEE802.11 system, multiple IFSs with different periods are defined, including a short inter frame space (SIFS: Short IFS) used for transmission frames assigned the highest priority, a polling inter frame space (PCF IFS: PIFS) used for transmission frames with relatively high priority, and a distributed control inter frame space (DCF IFS: DIFS) used for transmission frames with the lowest priority. When the base station device transmits a data frame using DCF, the base station device uses DIFS.

[0038] After waiting for the DIFS, the base station device waits for a random backoff time to prevent frame collision. In the IEEE802.11 system, a random backoff time called a contention window (CW) is used. In CSMA / CA, it is assumed that a transmission frame transmitted by a certain transmitting station is received by a receiving station without interference from other transmitting stations. Therefore, if transmitting stations transmit transmission frames at the same timing, the frames collide with each other and the receiving station cannot receive the frames correctly. Therefore, frame collision is avoided by having each transmitting station wait for a randomly set time before starting transmission. When the base station device determines that the wireless channel is in an idle state by carrier sense, it starts counting down the CW, and only when the CW reaches 0 does it acquire the right to transmit and can transmit a transmission frame to the terminal device. Note that if the base station device determines that the wireless channel is in a busy state by carrier sense during the CW countdown, it stops the CW countdown. Then, when the wireless channel becomes idle, the base station device resumes the countdown of the remaining CW following the previous IFS.

[0039] Next, the details of frame reception will be described. A terminal device, which is a receiving station, receives a transmission frame, reads the PHY header of the transmission frame, and demodulates the received transmission frame. The terminal device can then read the MAC header of the demodulated signal to determine whether the transmission frame is addressed to the terminal device itself. The terminal device can also determine the destination of the transmission frame based on information written in the PHY header (for example, a group identification number (GID: Group identifier, Group ID) written in VHT-SIG-A).

[0040] When a terminal device judges that the received transmission frame is addressed to itself and demodulates the transmission frame without error, it must transmit an ACK frame indicating that the frame was received correctly to the base station device, which is the transmitting station. The ACK frame is one of the highest priority transmission frames that is transmitted only by waiting for the SIFS period (no random backoff time is taken). The base station device ends a series of communications by receiving the ACK frame transmitted from the terminal device. Note that if the terminal device does not receive the frame correctly, the terminal device does not transmit an ACK. Therefore, if the base station device does not receive an ACK frame from the receiving station for a certain period (SIFS + ACK frame length) after transmitting a frame, it terminates the communication as it has failed. In this way, the end of one communication (also called a burst) in the IEEE802.11 system is always determined by the presence or absence of the reception of an ACK frame, except in special cases such as the transmission of a notification signal such as a beacon frame or the use of fragmentation to divide the transmission data.

[0041] When a terminal device determines that a received transmission frame is not addressed to the terminal device, the terminal device sets a network allocation vector (NAV) based on the length of the transmission frame described in the PHY header or the like. The terminal device does not attempt communication during the period set in the NAV. In other words, the terminal device performs the same operation as when the terminal device determines that the wireless channel is busy by the physical CS during the period set in the NAV, so communication control by the NAV is also called virtual carrier sense (virtual CS). In addition to being set based on information described in the PHY header, the NAV is also set by a request to send (RTS) frame or a clear to send (CTS) frame introduced to solve the hidden terminal problem.

[0042] In contrast to DCF, in which each device performs carrier sensing and autonomously acquires the transmission right, in PCF, a control station called a Point Coordinator (PC) controls the transmission right of each device within the BSS. In general, a base station device becomes the PC and acquires the transmission right for terminal devices within the BSS.

[0043] The communication period by PCF includes a contention free period (CFP) and a contention period (CP). During the CP, communication is performed based on the DCF described above, and during the CFP, the PC controls the transmission right. The base station device, which is the PC, broadcasts a beacon frame in which the CFP period (CFP Max duration) and the like are described in the BSS prior to PCF communication. Note that the PIFS is used for transmitting the beacon frame broadcast at the start of PCF transmission, and it is transmitted without waiting for the CW. The terminal device that receives the beacon frame sets the CFP period described in the beacon frame to the NAV. After that, until the NAV elapses or a signal (e.g., a data frame including CF-end) that broadcasts the end of CFP in the BSS is received, the terminal device can acquire the transmission right only when it receives a signal (e.g., a data frame including CF-poll) that signals the acquisition of the transmission right transmitted from the PC. During the CFP period, frame collisions do not occur within the same BSS, so each terminal device does not take the random backoff time used in DCF.

[0044] A wireless medium can be divided into a number of resource units (RUs). FIG. 1 is a schematic diagram showing an example of a division state of a wireless medium. For example, in resource division example 1, a wireless communication device can divide a frequency resource (subcarrier) which is a wireless medium into nine RUs. Similarly, in resource division example 2, a wireless communication device can divide a subcarrier which is a wireless medium into five RUs. Of course, the resource division example shown in FIG. 1 is merely an example, and for example, a number of RUs can be configured with different numbers of subcarriers. In addition, the wireless medium divided into RUs can include not only frequency resources but also spatial resources. A wireless communication device (e.g., an access point device) can transmit frames to a number of terminal devices (e.g., a number of station devices) simultaneously by arranging frames addressed to different terminal devices in each RU. An access point device can write information indicating the division state of a wireless medium (resource allocation information) in the PHY header of a frame transmitted by the device itself as common control information. Furthermore, the access point device can write information indicating the RU in which the frame addressed to each station device is placed (resource unit assignment information) as unique control information in the PHY header of the frame transmitted by the access point device itself.

[0045] Furthermore, multiple terminal devices (e.g., multiple station devices) can transmit frames simultaneously by placing frames in the assigned RUs and transmitting them. After receiving a frame (Trigger frame: TF) including trigger information transmitted from an access point device, multiple station devices can transmit frames after waiting for a predetermined period of time. Each station device can grasp the RU assigned to itself based on the information written in the TF. Furthermore, each station device can acquire an RU by random access based on the TF.

[0046] The access point device can simultaneously allocate multiple RUs to one station device. The multiple RUs can be configured with consecutive subcarriers or non-consecutive subcarriers. The access point device can transmit one frame using the multiple RUs allocated to one station device, and can allocate multiple frames to different RUs for transmission. At least one of the multiple frames can be a frame including common control information for transmitting resource allocation information to multiple station devices.

[0047] A single station device can be assigned multiple RUs by the access point device. The station device can transmit one frame using the assigned multiple RUs. Also, the station device can assign multiple frames to different RUs and transmit them using the assigned multiple RUs. The multiple frames can be frames of different frame types.

[0048] The access point device can also assign multiple AIDs to one station device. The access point device can assign RUs to the multiple AIDs assigned to one station device. The access point device can transmit different frames to the multiple AIDs assigned to one station device using the assigned RUs. The different frames can be frames of different frame types.

[0049] One station device can also be assigned multiple AIDs by the access point device. One station device can be assigned RUs for each of the assigned AIDs. One station device recognizes all RUs assigned to the multiple AIDs assigned to the own device as RUs assigned to the own device, and can transmit one frame using the assigned multiple RUs. One station device can also transmit multiple frames using the assigned multiple RUs. At this time, the multiple frames can be transmitted with information indicating the AIDs associated with the assigned RUs written therein. One station device can transmit different frames for the assigned AIDs using the assigned RUs. The different frames can be frames of different frame types.

[0050] Hereinafter, information exchanged when one wireless communication device communicates with another wireless communication device will also be referred to as data.

[0051] The wireless communication device has either or both of a function for transmitting and receiving a PPDU. Fig. 2 is a diagram showing an example of the configuration of a PPDU transmitted by a wireless communication device. A PPDU conforming to the IEEE802.11a / b / g standard is configured to include an L-STF, an L-LTF, an L-SIG, and a Data frame (MAC Frame, a MAC frame, a payload, a data section, data, information bits, etc.). A PPDU conforming to the IEEE802.11n standard is configured to include an L-STF, an L-LTF, an L-SIG, an HT-SIG, an HT-STF, an HT-LTF, and a Data frame. A PPDU conforming to the IEEE802.11ac standard is configured to include an L-STF, an L-LTF, an L-SIG, a VHT-SIG-A, a VHT-STF, a VHT-LTF, a VHT-SIG-B, and a part or all of a Data frame. The PPDU in the IEEE802.11ax standard includes some or all of the following: L-STF, L-LTF, L-SIG, RL-SIG in which L-SIG is repeated over time, HE-SIG-A, HE-STF, HE-LTF, HE-SIG-B, and Data frames. The PPDU considered in the IEEE802.11be standard includes some or all of the following: L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-SIG, EHT-STF, EHT-LTF, and Data frames.

[0052] The L-STF, L-LTF, and L-SIG enclosed by dotted lines in Fig. 2 are configurations commonly used in the IEEE 802.11 standard (hereinafter, L-STF, L-LTF, and L-SIG are also collectively referred to as L-header). For example, a wireless communication device compatible with the IEEE 802.11a / b / g standard can properly receive an L-header in a PPDU compatible with the IEEE 802.11n / ac / ax / be standard. A wireless communication device compatible with the IEEE 802.11a / b / g standard can receive a PPDU compatible with the IEEE 802.11n / ac / ax / be standard as a PPDU compatible with the IEEE 802.11a / b / g standard.

[0053] However, wireless communication devices that comply with the IEEE802.11a / b / g standards cannot demodulate the PPDU that follows the L-header and complies with the IEEE802.11n / ac / ax / be standards, and therefore cannot demodulate information related to the transmitter address (TA: Transmitter Address), receiver address (RA: Receiver Address), or the Duration / ID field used to set the NAV.

[0054] IEEE802.11 specifies a method of inserting Duration information into L-SIG as a method for wireless communication devices conforming to the IEEE802.11a / b / g standards to appropriately set NAV (or to perform reception for a predetermined period of time). Information on the transmission rate in the L-SIG (RATE field, L_RATE field, L_RATE, L_DATARATE, L_DATARATE field) and information on the transmission period (LENGTH field, L_LENGTH field, L_LENGTH) are used by wireless communication devices conforming to the IEEE802.11a / b / g standards to appropriately set NAV.

[0055] FIG. 3 is a diagram showing an example of a method of inserting Duration information into an L-SIG. In FIG. 3, a PPDU configuration corresponding to the IEEE802.11ac standard is shown as an example, but the PPDU configuration is not limited to this. A PPDU configuration corresponding to the IEEE802.11n standard and a PPDU configuration corresponding to the IEEE802.11ax standard may also be used. TXTIME includes information on the length of the PPDU, aPreambleLength includes information on the length of the preamble (L-STF+L-LTF), and aPLCPHeaderLength includes information on the length of the PLCP header (L-SIG). L_LENGTH includes a Signal Extension, which is a virtual period set to achieve compatibility with the IEEE802.11 standard, and an N related to L_RATE. opsIt is calculated based on aSymbolLength, which is information about the duration of one symbol (symbol, OFDM symbol, etc.), aPLCPServiceLength, which indicates the number of bits included in the PLCP Service field, and aPLCPConvolutionalTailLength, which indicates the number of tail bits of the convolutional code. The wireless communication device can calculate L_LENGTH and insert it into the L-SIG. The wireless communication device can also calculate L-SIG Duration. The L-SIG Duration indicates information about the duration obtained by adding up the duration of the PPDU including L_LENGTH and the duration of the Ack and SIFS that are expected to be transmitted from the destination wireless communication device in response to the PPDU.

[0056] An example of the format of a MAC Frame is shown in Figure 9. The MAC Frame here refers to the Data Frame (MAC Frame, MAC frame, payload, data section, data, information bits, etc.) in Figure 2 and the MAC Frame in Figure 3. The MAC Frame includes Frame Control, Duration / ID, Address 1, Address 2, Address 3, Sequence Control, Address 4, QoS Control, HT Control, Frame Body, and FCS.

[0057] FIG. 4 is a diagram showing an example of L-SIG Duration in L-SIG TXOP Protection. DATA (frame, payload, data, etc.) is composed of a MAC frame and a part or both of the PLCP header. Also, BA is Block Ack or Ack. PPDU includes L-STF, L-LTF, and L-SIG, and can further include any one or more of DATA, BA, RTS, and CTS. In the example shown in FIG. 4, L-SIG TXOP Protection using RTS / CTS is shown, but CTS-to-Self may also be used. Here, MAC Duration is a period indicated by the value of the Duration / ID field. Also, the Initiator can transmit a CF_End frame to notify the end of the L-SIG TXOP Protection period.

[0058] Next, a method for identifying a BSS from a frame received by a wireless communication device will be described. In order for a wireless communication device to identify a BSS from a frame received, it is preferable for the wireless communication device transmitting a PPDU to insert information for identifying the BSS (BSS Color, BSS identification information, a value unique to the BSS) into the PPDU, and it is possible to describe information indicating the BSS Color in the HE-SIG-A.

[0059] The wireless communication device can transmit the L-SIG multiple times (L-SIG Repetition). For example, the receiving wireless communication device receives the L-SIG transmitted multiple times using MRC (Maximum Ratio Combining), thereby improving the demodulation accuracy of the L-SIG. Furthermore, when the wireless communication device has correctly received the L-SIG using MRC, the wireless communication device can interpret the PPDU including the L-SIG as a PPDU that complies with the IEEE802.11ax standard.

[0060] The wireless communication device can receive a part of a PPDU other than the PPDU (for example, a preamble, L-STF, L-LTF, PLCP header, etc., defined by IEEE802.11) even during a PPDU reception operation (also referred to as a dual reception operation). When the wireless communication device detects a part of a PPDU other than the PPDU during a PPDU reception operation, the wireless communication device can update a destination address, a source address, and part or all of information related to the PPDU or DATA period.

[0061] ACK and BA may also be called responses (response frames). In addition, a probe response, an authentication response, and a connection response may also be called responses. [1. First embodiment]

[0062] FIG. 5 is a diagram showing an example of a wireless communication system according to the present embodiment. The wireless communication system 3-1 includes a wireless communication device 1-1 and wireless communication devices 2-1 to 2-3. The wireless communication device 1-1 is also referred to as a base station device 1-1, and the wireless communication devices 2-1 to 2-3 are also referred to as terminal devices 2-1 to 2-3. The wireless communication devices 2-1 to 2-3 and the terminal devices 2-1 to 2-3 are also referred to as a wireless communication device 2A and a terminal device 2A, as devices connected to the wireless communication device 1-1. The wireless communication device 1-1 and the wireless communication device 2A are wirelessly connected, and are in a state in which they can transmit and receive PPDUs to each other. The wireless communication system according to the present embodiment may include a wireless communication system 3-2 in addition to the wireless communication system 3-1. The wireless communication system 3-2 includes a wireless communication device 1-2 and wireless communication devices 2-4 to 2-6. The wireless communication device 1-2 is also referred to as a base station device 1-2, and the wireless communication devices 2-4 to 2-6 are also referred to as terminal devices 2-4 to 2-6. Moreover, the wireless communication devices 2-4 to 2-6 and the terminal devices 2-4 to 2-6 are also referred to as the wireless communication device 2B and the terminal device 2B as devices connected to the wireless communication device 1-2. The wireless communication system 3-1 and the wireless communication system 3-2 form different BSSs, but this does not necessarily mean that the ESSs (Extended Service Sets) are different. The ESS indicates a service set forming a LAN (Local Area Network). In other words, wireless communication devices belonging to the same ESS can be considered to belong to the same network from a higher layer. The BSSs are also coupled via a DS (Distribution System) to form an ESS. Each of the wireless communication systems 3-1 and 3-2 can further include a plurality of wireless communication devices.

[0063] In the following description of FIG. 5, it is assumed that a signal transmitted by the wireless communication device 2A reaches the wireless communication device 1-1 and the wireless communication device 2B, but does not reach the wireless communication device 1-2. In other words, when the wireless communication device 2A transmits a signal using a certain channel, the wireless communication device 1-1 and the wireless communication device 2B determine that the channel is busy, while the wireless communication device 1-2 determines that the channel is idle. Also, it is assumed that a signal transmitted by the wireless communication device 2B reaches the wireless transmission device 1-2 and the wireless communication device 2A, but does not reach the wireless communication device 1-1. In other words, when the wireless communication device 2B transmits a signal using a certain channel, the wireless communication device 1-2 and the wireless communication device 2A determine that the channel is busy, while the wireless communication device 1-1 determines that the channel is idle.

[0064] 6 is a diagram showing an example of the device configuration of wireless communication devices 1-1, 1-2, 2A, and 2B (hereinafter, collectively referred to as wireless communication device 10-1, station device 10-1, or simply station device). Wireless communication device 10-1 includes an upper layer unit (upper layer processing step) 10001-1, an autonomous distributed control unit (autonomous distributed control step) 10002-1, a transmitting unit (transmitting step) 10003-1, a receiving unit (receiving step) 10004-1, and an antenna unit 10005-1.

[0065] The upper layer unit 10001-1 performs information processing on layers higher than the physical layer, such as the MAC layer and LLC layer, for information handled within the wireless communication device itself (such as information related to transmitted frames and MIB (Management Information Base)) and frames received from other wireless communication devices.

[0066] The upper layer unit 10001-1 can notify the autonomous distributed control unit 10002-1 of information about frames and traffic being transmitted to a wireless medium. The information about frames and traffic may be, for example, control information included in a management frame such as a beacon, or measurement information reported by another wireless communication device to the wireless communication device itself. Furthermore, the information may be control information included in a management frame or a control frame without limiting the destination (it may be addressed to the device itself, may be addressed to another device, or may be broadcast or multicast).

[0067] 7 is a diagram showing an example of the device configuration of the autonomous distributed control unit 10002-1. The autonomous distributed control unit 10002-1 is also called a control unit 10002-1, and includes a CCA unit (CCA step) 10002a-1, a backoff unit (backoff step) 10002b-1, and a transmission decision unit (transmission decision step) 10002c-1.

[0068] The CCA unit 10002a-1 can use either or both of information on the power of a signal received via a wireless resource and information on the received signal (including information after decoding) notified from the receiving unit 10004-1 to perform a state determination of the wireless resource (including a determination of whether the wireless resource is busy or idle). The CCA unit 10002a-1 can notify the backoff unit 10002b-1 and the transmission determination unit 10002c-1 of the state determination information of the wireless resource.

[0069] The backoff unit 10002b-1 can perform backoff using wireless resource state determination information. The backoff unit 10002b-1 generates a CW and has a countdown function. For example, when the wireless resource state determination information indicates an idle state, the backoff unit 10002b-1 can execute a CW countdown, and when the wireless resource state determination information indicates a busy state, the backoff unit 10002b-1 can stop the CW countdown. The backoff unit 10002b-1 can notify the transmission determination unit 10002c-1 of the value of the CW.

[0070] The transmission decision unit 10002c-1 makes a transmission decision using either or both of the wireless resource status decision information and the CW value. For example, when the wireless resource status decision information indicates "idle" and the CW value is 0, the transmission decision unit 10003-1 can be notified of the transmission decision information. Also, when the wireless resource status decision information indicates "idle," the transmission decision unit 10003-1 can be notified of the transmission decision information.

[0071] The transmitting unit 10003-1 includes a physical layer frame generating unit (physical layer frame generating step) 10003a-1 and a wireless transmitting unit (wireless transmitting step) 10003b-1. The physical layer frame generating unit (physical layer frame generating step) may be called a frame generating unit (frame generating step). The physical layer frame generating unit 10003a-1 has a function of generating a physical layer frame (hereinafter also called a frame or PPDU) based on the transmission decision information notified from the transmission decision unit 10002c-1. The physical layer frame generating unit 10003a-1 includes an encoding unit that performs error correction encoding processing on data received from a higher layer to generate an encoded block. The physical layer frame generating unit 10003a-1 also has a function of performing modulation, precoding filter multiplication, etc. The physical layer frame generating unit 10003a-1 sends the generated physical layer frame to the wireless transmitting unit 10003b-1.

[0072] The frame generated by the physical layer frame generator 10003a-1 includes a trigger frame that instructs the wireless communication device, which is the destination terminal, to transmit the frame. The trigger frame includes information indicating the RU to be used when the wireless communication device instructed to transmit the frame transmits the frame.

[0073] The wireless transmission unit 10003b-1 converts the physical layer frame generated by the physical layer frame generation unit 10003a-1 into a radio frequency (RF) band signal to generate a radio frequency signal. The processing performed by the wireless transmission unit 10003b-1 includes digital-to-analog conversion, filtering, frequency conversion from the baseband band to the RF band, and the like.

[0074] The receiving unit 10004-1 includes a wireless receiving unit (wireless receiving step) 10004a-1 and a signal demodulating unit (signal demodulating step) 10004b-1. The receiving unit 10004-1 generates information about the received signal power from the RF band signal received by the antenna unit 10005-1. The receiving unit 10004-1 can notify the CCA unit 10002a-1 of the information about the received signal power and the information about the received signal.

[0075] The wireless receiver 10004a-1 has a function of converting an RF signal received by the antenna unit 10005-1 into a baseband signal and generating a physical layer signal (e.g., a physical layer frame). The processing performed by the wireless receiver 10004a-1 includes frequency conversion from the RF band to the baseband, filtering, and analog-to-digital conversion.

[0076] The signal demodulation unit 10004b-1 has a function of demodulating the physical layer signal generated by the wireless receiving unit 10004a-1. The processing performed by the signal demodulation unit 10004b-1 includes channel equalization, demapping, error correction decoding, and the like. The signal demodulation unit 10004b-1 can extract, for example, information contained in the PHY header, information contained in the MAC header, and information contained in the transmission frame from the physical layer signal. The signal demodulation unit 10004b-1 can notify the extracted information to the upper layer unit 10001-1. The signal demodulation unit 10004b-1 can extract any or all of the information contained in the PHY header, information contained in the MAC header, and information contained in the transmission frame. The evaluation unit (evaluation step) (10004c-1) performs a predetermined evaluation of the information contained in the PHY header, MAC header, and the like thus extracted, and notifies the upper layer unit of the contents according to the evaluation.

[0077] The antenna unit 10005-1 has a function of transmitting the radio frequency signal generated by the radio transmission unit 10003b-1 into a radio space, and also has a function of receiving the radio frequency signal and passing it to the radio reception unit 10004a-1.

[0078] The wireless communication device 10-1 can cause the wireless communication devices around the wireless communication device to set NAV for only the period by describing information indicating the period during which the wireless communication device uses the wireless medium in the PHY header or MAC header of the frame to be transmitted. For example, the wireless communication device 10-1 can describe information indicating the period in the Duration / ID field or LENGTH field of the frame to be transmitted. The NAV period set in the wireless communication devices around the wireless communication device is called the TXOP period (or simply TXOP) acquired by the wireless communication device 10-1. The wireless communication device 10-1 that has acquired the TXOP is called a TXOP acquirer (TXOP holder). The frame type of the frame transmitted by the wireless communication device 10-1 to acquire the TXOP is not limited to any particular type, and may be a control frame (for example, an RTS frame or a CTS-to-self frame) or a data frame.

[0079] The wireless communication device 10-1, which is a TXOP holder, can transmit frames to wireless communication devices other than the wireless communication device itself during the TXOP. When the wireless communication device 1-1 is a TXOP holder, the wireless communication device 1-1 can transmit frames to the wireless communication device 2A during the TXOP period. Furthermore, the wireless communication device 1-1 can instruct the wireless communication device 2A to transmit a frame addressed to the wireless communication device 1-1 during the TXOP period. The wireless communication device 1-1 can transmit a trigger frame including information instructing the wireless communication device 2A to transmit a frame addressed to the wireless communication device 1-1 during the TXOP period.

[0080] The wireless communication device 1-1 may reserve a TXOP for all communication bands (e.g., Operation bandwidth) over which frames may be transmitted, or may reserve a TXOP for a specific communication band (Band), such as a communication band (e.g., Transmission bandwidth) over which frames will actually be transmitted.

[0081] The wireless communication device that instructs the wireless communication device 1-1 to transmit a frame during the period of the TXOP acquired by the wireless communication device 1-1 is not necessarily limited to the wireless communication device connected to the wireless communication device itself. For example, the wireless communication device can instruct a wireless communication device that is not connected to the wireless communication device itself to transmit a frame in order to make a wireless communication device in the vicinity of the wireless communication device itself transmit a management frame such as a Reassociation frame or a control frame such as an RTS / CTS frame.

[0082] In addition, we will also explain TXOP in EDCA, which is a data transmission method different from DCF. The IEEE802.11e standard is related to EDCA, and specifies TXOP from the viewpoint of QoS (Quality of Service) guarantee for various services such as video transmission and VoIP (Voice over IP). Services are roughly classified into four access categories: VO (VOice), VI (VIdeo), BE (Best Effort), and BK (Background). Generally, the order of priority is VO, VI, BE, and BK. Each access category has parameters such as the minimum value of CW, CWmin, the maximum value, AIFS (Arbitration IFS), which is a type of IFS, and TXOP limit, which is the upper limit of transmission opportunities, and the values ​​are set to give a difference in priority. For example, the CWmin, CWmax, and AIFS of VO, which has the highest priority for voice transmission, can be set to relatively small values ​​compared to other access categories, enabling data transmission with priority over other access categories. For example, in a VI where the amount of data transmitted is relatively large for video transmission, by setting the TXOP limit large, it is possible to secure a longer transmission opportunity than in other access categories.In this way, the values ​​of the four parameters for each access category are adjusted to guarantee QoS according to various services.

[0083] Next, an example of implementation of a direct link will be described with reference to FIG. 8. Among the symbols used in FIG. 8, the same symbols as those in FIG. 5 are the same as those described in FIG. 5. The wireless system 3-1 includes a base station device 1-1, a terminal device 2-1 (wireless communication device 2-1), a terminal device 2-2 (wireless communication device 2-2), and a terminal device 2-3 (wireless communication device 2-3). When the terminal device 2-2 transmits data to the terminal device 2-1, a direct link is defined as a communication (4-1) via the base station device 1-1 and a direct communication (4-2) from the terminal device 2-2 to the terminal device 2-1 without passing through the base station device 1-1. When a direct link is used, the terminal device 2-1 transmits a direct link discovery request to the terminal device 2-2 via the base station device 1-1. The terminal device 2-2 that receives the direct link discovery request via the base station device 1-1 transmits a direct link discovery response to the terminal device 2-1 using a direct path. When the terminal device 2-1 successfully receives this direct link discovery response, it becomes clear that direct communication is possible between the terminal device 2-1 and the terminal device 2-2.

[0084] Thereafter, the terminal device 2-1 transmits a direct link setup request to the terminal device 2-2 via the base station device 1-1. The terminal device 2-1 that transmits this direct link setup request may also be called an initiator. The terminal device 2-2 that receives the direct link setup request transmits a direct setup response to the terminal device 2-1 via the base station device 1-1. The terminal device 2-2 that transmits this direct setup response may also be called a responder. After the direct link setup request and the direct link setup response are normally exchanged, a direct link is established, and the terminal devices 2-1 and 2-2 can communicate directly with each other without passing through the base station device 1-1. The direct link setup request and the direct link setup response may include various control information, such as information used in encrypted communication, for example, control information such as information related to a key. If information used in encrypted communication is exchanged at the time of exchanging the direct link setup request and the direct link setup response, encryption may be used in the direct link.

[0085] Next, the inter-BSS spatial reuse operation will be described with reference to FIG. 8. Even if an interference signal is added to a desired signal in wireless communication, if the ratio of the power of the interference signal and noise to the power of the desired signal is equal to or greater than a predetermined value, the desired signal can be demodulated and decoded. This means that when communication is being performed at a long distance, that is, when the terminal device performing the communication is sufficiently far away, communication between multiple terminal devices at a relatively short distance can be performed simultaneously with the distant communication. A transmission operation using overlapping wireless media utilizing the difference in path loss caused by the arrangement of the terminal devices in this way is called a spatial reuse operation. Hereinafter, the spatial reuse operation may be abbreviated as SR.

[0086] As an example, a case will be described in which a wireless communication device 2-6 in a wireless system 3-2 performs simultaneous transmission by SR for a signal transmitted by a terminal device 2-3 to a base station device 1-1 in a wireless system 3-1. In this case, whether transmission by SR can be performed without problems depends on how much the SINR (Signal to Interference Noise Ratio) of the signal of the terminal device 2-3 received by the base station device 1-1 is degraded by the transmission of the terminal device 2-6. If the path loss from the terminal device 2-6 to the base station device 1-1 is sufficiently large and the transmission power of the terminal device 2-6 is sufficiently small, degradation of the SINR of the signal of the terminal device 2-3 received by the base station device 1-1 is allowed. Various methods can be used to ensure the path loss from the terminal device 2-6 to the base station device 1-1. One example is inter-BSS SR, which performs SR assuming that sufficient path loss is guaranteed when the wireless systems (BSSs) to which the terminal devices belong are different. When the terminal device 2-6 in the wireless system 3-2 receives the signal 4-3 transmitted by the terminal device 2-3 in the wireless system 3-1, it reads the PHY header of the wireless frame of the signal 4-3 and determines which wireless system the signal 4-3 is transmitted from. At this time, it may use information contained in the PHY header that is an abbreviation of an identifier indicating a wireless system called BSS Color to identify that the signal is a wireless frame transmitted from a wireless system other than the wireless system 3-2.

[0087] After identifying that the signal 4-3 is a wireless frame signal received from another wireless system, the terminal device 2-6 may read a NAV (Network Allocation Vector) indicating the transmission time of the signal 4-3 from the PHY header of the signal 4-3, prepare transmission data (wireless frame) so that the transmission is completed by the time indicated by the NAV, and transmit the data to the base station device 1-2 (signal 4-4). During this transmission, the terminal device 2-6 may control the transmission power so as to reduce interference with the base station device and the terminal device included in the wireless system 3-1. Information used for this transmission power may be received from the base station device 1-2. In addition, the terminal device 2-6 may perform transmission power control using the reception power when various LTFs included in the preamble of the signal 4-3 are received. In addition, the reception power when various LTFs included in the preamble of the signal 4-3 are received may be used as the representative reception power of the signal 4-3.

[0088] In this embodiment, communication within the same wireless system is used as the target for SR (intra-BSS SR operation). SR for direct link communication within the same wireless system is taken as an example and will be described with reference to FIG. 10. Among the symbols used in FIG. 10, the same symbols as those in FIG. 5 are the same as those described in FIG. 5. The wireless system 3-1 includes a base station device 1-1 and terminal devices 2-1 to 2-3. It is assumed that the terminal device 2-1 and the terminal device 2-2 have already been set up for a direct link. The terminal device 2-3 transmits to the base station device 1-1 (signal 5-1). The terminal device 2-2 has data to transmit to the terminal device 2-1, in other words, data that can be transmitted using a direct link, but once it detects the signal 5-1 by carrier sense, it stops transmitting. After detecting the signal 5-1, the terminal device 2-2 receives the PHY header of the signal 5-1. From this PHY header, it obtains NAV (duration information) indicating the length of the signal 5-1. Thereafter, terminal device 2-2 sets the length of the transmission data (length of the radio frame) so that it does not exceed the NAV indicating the length of signal 5-1 (length of the radio frame), and after setting the transmission power, may transmit data (radio frame) to terminal device 2-1 by superimposing it on signal 5-1 (signal 5-2).

[0089] The procedure for performing SR will be described in detail below with reference to the drawings. FIG. 11 shows an overview of the positional relationship of devices. Among the symbols used in FIG. 11, the same symbols as those in FIG. 5 are the same as those explained in FIG. 5. The wireless system 3-1 includes a base station device 1-1 and terminal devices 2-1 to 2-5. The base station device 1-1 and the terminal devices 2-1 to 2-5 are assumed to support SR using a direct link. When participating in the wireless system 3-1, the wireless communication devices 2-1 to 2-5 transmit an association request to the base station device 1-1 and receive an association response transmitted from the base station device. FIG. 13(b) shows the message flow at this time. In FIG. 13(b), as an example, the terminal device 2-1 transmits an association request to the base station device 1-1. 2111 is the association request transmitted from the terminal device 2-1 to the base station device 1-1, and 2112 is the association response transmitted from the base station device 1-1 to the terminal device 2-1. The association request includes the capability information of the terminal device 2-1, and the association response includes the capability information of the base station device 1-1. The base station device 1-1 may also notify the BSS Color used to identify the BSS managed by the base station device 1-1. The base station device 1-1 may also change the BSS Color and notify the associated terminal device of the change.

[0090] In this embodiment, the capability information includes information indicating that intra-BSS SR is supported. As an example, it is assumed that there are two types of intra-BSS SR methods, PD-based SR and PSR-based SR, and information indicating whether or not each of PD-based SR and PSR-based SR is supported is included in the capability information. From the capability information obtained from the base station device 1-1, the terminal device 2-1 can know whether the wireless system 3-1 supports intra-BSS SR, and if intra-BSS SR is supported, whether each of PD-based SR and PSR-based SR is supported. In addition, the base station device 1-1 can know whether the terminal device 2-1 supports intra-BSS SR, and if intra-BSS SR is supported, whether each of PD-based SR and PSR-based SR is supported.

[0091] Next, an example of a flow when a terminal device sets up direct communication will be described with reference to FIG. 12. As an example, a flow will be described when the terminal device 2-1 sets up direct communication with the terminal device 2-2, and then the terminal device 2-3 sets up direct communication with the terminal device 2-4. First, the terminal device 2-1 transmits a direct link setup request to the terminal device 2-2 via the base station device 1-1. 2001 is a direct link setup request from the terminal device 2-1 to the base station device 1-1, and 2002 is a direct link setup request from the base station device 1-1 to the terminal device 2-2. After receiving the direct link setup request transmitted from the terminal device 2-1 via the base station device 1-1, the terminal device 2-2 transmits a direct link setup response to the terminal device 2-1 via the base station device 1-1. 2003 is a direct link setup response from the terminal device 2-2 to the base station device 1-1, and 2004 is a direct link setup response from the base station device 1-1 to the terminal device 2-1. After receiving the direct link setup response, the terminal device 2-1 transmits a direct link setup acknowledgement to the terminal device 2-2 via the base station device 1-1. 2005 is a direct link setup acknowledgement from the terminal device 1-1 to the base station device 1-1, and 2006 is a direct link setup acknowledgement from the base station device to the terminal device 2-2.

[0092] The terminal device 2-1 may include information indicating whether the terminal device 2-1 supports intra-BSS SR in the direct link setup request 2001. This information indicating whether the terminal device 2-1 supports intra-BSS SR is transmitted to the terminal device 2-2 via the base station device 1-1. The terminal device 2-2 may include information (capability information) indicating whether the terminal device 2-2 supports intra-BSS SR in the direct link setup response 2003. This information indicating whether the terminal device 2-2 supports intra-BSS SR is transmitted to the terminal device 2-1 via the base station device 1-1. The terminal device 2-1 and the terminal device 2-2 can determine which terminal among the base station device 1-1, the terminal device 2-1, and the terminal device 2-2 supports intra-BSS SR from this capability information and the capability information exchanged at the time of association. Furthermore, when terminal device 2-1 and terminal device 2-2 support intra-BSS SR, they can determine whether they support PD-based SR, whether they support PSR-based SR, or whether they support both PD-based SR and PSR-based SR. Having received information indicating whether terminal device 2-2 supports intra-BSS SR, terminal device 2-1 transmits a direct link setup acknowledgement including information specifying one of the intra-BSS SR methods supported by terminal device 2-1, terminal device 2-2, and base station device 1-1 to terminal device 2-2 via base station device 1-1. By exchanging a direct link acknowledgement including information specifying one of the intra-BSS SR methods, direct transmission is set up between terminal device 2-1 and terminal device 2-2, and base station device 1-1 can know that direct transmission is set up between terminal device 2-1 and terminal device 2-2, and can know whether this direct communication corresponds to intra-BSS SR, intra-BSS SR using PD-base SR, or intra-BSS SR using PSR-based SR.

[0093] When the base station device 1-1 receives the direct link setup acknowledgement 2005, it generates SR link information. This SR link information can include multiple pieces of information, and may include, for example, information indicating a terminal device that has set up direct communication corresponding to the intra-BSS SR, and information indicating the intra-BSS SR method that the direct communication corresponding to the intra-BSS SR supports. As an example, the SR link information generated after the direct link setup acknowledgement 2006 may include information indicating the terminal device 2-1, information indicating the terminal device 2-2, and a color index linked to the information indicating the terminal device 2-1 and the information indicating the terminal device 2-2. The information indicating the terminal device 2-1 and the information indicating the terminal device 2-2 may use the MAC address of the terminal device 2-1 and the MAC address of the terminal device 2-2, respectively. Also, they may be the AID (association ID) of the terminal device 2-1 and the AID of the terminal device 2-2. Also, they may be shortened MAC addresses and AIDs. The color index is information for distinguishing one or more set direct communications corresponding to the intra-BSS SR. The total number of color indexes may be less than the total number of all combinations of direct communication that can be set. As an example, 0 to 63 that can be expressed by 6 bits may be used. Also, a part of the color index, for example, 0 in the case of a 6-bit color index, may be used as a value indicating direct communication that does not support intra-BSS SR. In this embodiment, 1 is set as the color index corresponding to the direct link setup acknowledgement 2005. Also, if SR link information has been generated before receiving the direct link setup acknowledgement 2005, the generated SR link information may be updated by adding information indicating the terminal device 2-1, information indicating the terminal device 2-2, and color indexes linked to the information indicating the terminal device 2-1 and the information indicating the terminal device 2-2. The base station device 1-1 transmits the generated or updated SR link information to one or more terminal devices by broadcast communication, multicast communication, or unicast communication.In this embodiment, SR link information is included in the intraBSS-SR announce information 2007, and the intraBSS-SR announce information 2007 is transmitted by broadcast communication to terminal device 2-1, terminal device 2-2, terminal device 2-3, and terminal device 2-4 connected to base station device 1-1.

[0094] Terminal device 2-1 and terminal device 2-2, which receive the intraBSS-SR announce information 2007, can know the color index (1) to be used in the direct link set up in the direct link setup acknowledgments 2005 and 2006, and terminal device 2-3 and terminal device 2-4, which receive the intraBSS-SR announce information 2007, can know that direct communication corresponding to intra-BSS SR has been set up between terminal device 2-1 and terminal device 2-2, and that the color index to be used in that direct communication is 1.

[0095] In this embodiment, the color index set by the base station device 1-1 is notified by intraBSS-SR announce information, but the color index may be included in the direct link setup acknowledgement 2006 sent by the base station device 1-1. In this case, the color index corresponding to the information of the direct communication set up between the terminal device 2-1 and the terminal device 2-2 may be notified to the terminal device 2-1 by unicast communication.

[0096] Next, the terminal device 2-3 sets up direct communication with the terminal device 2-4. The messages and flow used for the setting are the same as when the terminal device 2-1 sets up direct communication with the terminal device 2-2. The terminal device 2-3 transmits a direct link setup request to the terminal device 2-4 via the base station device. 2001-1 is a direct link setup request directed to the base station device, and 2002-1 is a direct link setup request directed to the terminal device 2-4. The terminal device 2-4 that receives the direct link setup request 2002-1 transmits a direct link setup response to the terminal device 2-3 via the base station device 1-1. 2003-1 is a direct link setup response directed to the base station device 1-1, and 2004-1 is a direct link setup response directed to the terminal device 2-3. The terminal device 2-3 that receives the direct link setup response 2004-1 transmits a direct link setup acknowledgement to the terminal device 2-4 via the base station device 1-1. 2005-1 is a direct link setup acknowledgement directed to the base station apparatus 1-1, and 2006-1 is a direct link setup acknowledgement directed to the terminal apparatus 2-4. Subsequently, the base station apparatus 1-1, which has received the direct link setup acknowledgement 2005-1, transmits intraBSS-SR announce information 2007-1 by broadcast communication to the terminal apparatus 2-1, terminal apparatus 2-2, terminal apparatus 2-3, and terminal apparatus 2-4. The direct link setup requests 2001-1 and 2002-1 may include capability information related to intra-BSS SR of the terminal apparatus 2-3. Furthermore, the direct link setup responses 2003-1 and 2004-1 may include capability information related to intra-BSS SR of the terminal apparatus 2-4. Furthermore, the direct link setup acknowledgements 2005-1 and 2006-1 may include information specifying one of the intra-BSS SR methods supported by the terminal apparatus 2-3, terminal apparatus 2-4, and base station apparatus 1-1.The intraBSS-SR announce information 2007-1 may include updated SR link information, and in addition to the SR link information included in the intraBSS-SR announce information 2007, may include information indicating the terminal device 2-3, information indicating the terminal device 2-4, and a color index linked to the information indicating the terminal device 2-3 and the information indicating the terminal device 2-4. As an example, 2 may be used as this color index. As a result, the updated SR link information may include the MAC address of the terminal device 2-1, the MAC address of the terminal device 2-2, a color index (1) linked to the MAC address of the terminal device 2-1 and the MAC address of the terminal device 2-2, the MAC address of the terminal device 2-3, the MAC address of the terminal device 2-4, and a color index (2) linked to the MAC address of the terminal device 2-3 and the MAC address of the terminal device 2-4.

[0097] An example of the structure of an information element indicating a color index and two terminal devices linked to the color index is shown in FIG. 15(b). Hereinafter, this information element is referred to as a color index information element. 1531 is an element ID, and 1533 is an element ID extension. These two fields identify the type of information element. 1532 is a length field indicating the length of the color index information element, and 1534 is an Intra-BSS Color Bitmap field indicating which color index is valid, with each bit of the 8 octets (=64 bits) indicating which color index is being used. The lowest bit corresponds to color index 0, and the highest bit corresponds to color index 63. When the bit value is 0, the corresponding color index is not being used, and when the bit value is 1, the corresponding color index is being used. The Intra-BSS Color Bitmap field 1534 is followed by the MAC address of the terminal device corresponding to the color index being used. 1535 corresponds to color index 0 and is the MAC address of the terminal device that initiated the setup of direct communication, 1536 corresponds to color index 0 and is the MAC address of the terminal device that responded to the setup of direct communication, 1537 corresponds to color index 1 and is the MAC address of the terminal device that initiated the setup of direct communication, and 1538 corresponds to color index 1 and is the MAC address of the terminal device that responded to the setup of direct communication. Below, the MAC address pairs are arranged in the order of the color index, 1539 corresponds to color index 63 and is the MAC address of the terminal device that initiated the setup of direct communication, and 1540 corresponds to color index 63 and is the MAC address of the terminal device that responded to the setup of direct communication. The field indicating each MAC address is assigned a length of 6 octets when the corresponding bit in the Intra-BSS Color Bitmap field 1534 is 1, and a length of 0 octet when the corresponding bit is 0. In other words, when the bit corresponding to a certain color index is 0, the MAC address information is not included, and the corresponding information is omitted.In this example, a small color index value is assigned to the low-order bit of the Intra-BSS Color Bitmap field, but this is not limited to this and a small color index value may be assigned to the high-order bit. Also, the fields indicating the MAC addresses of each terminal device are arranged in ascending order of color index, but this is not limited to this and they may be arranged in ascending order of color index. When direct communication is set between terminal devices corresponding to intra-BSS SR, the base station device 1-1 updates the content of this color index information element. This updated color index information element may be transmitted to one or more terminal devices connected to the base station device 1-1 by broadcast communication, multicast communication, or unicast communication. When the base station device 1-1 receives a request for this color index information element from any of the connected terminal devices, it may transmit the color index information element to that terminal device.

[0098] When specifying PD-based SR as the intra-BSS SR method when setting up direct communication, the base station device 1-1 may include information on the power detection level used in PD-based SR in the SR link information. Various methods can be used to set the power detection level, but one example is a method in which the transmission power and the power detection level are defined by a relational equation and upper and lower limits are set for the power detection level. An example of setting the transmission power and the power detection level is shown in Figure 14. When the transmission power is TX_PWR ref The power detection level set when min The maximum power detection level is PD max And use the following relational expression: PD level ≦ max(PD min , min(PD max , P.D. min +(TX_PWR ref -TX_PWR)))+log10(PPDU_BW / 20MHz) (Number 1) PD levelis the power detection level to be set, TX_PWR is the transmission power to be set when transmitting PPDU, and PPDU_BW is the frequency bandwidth of the PPDU (wireless frame) to be transmitted. max and P.D. min There is a default value, and you can set an offset value for each. max and P.D. min The default value of is not uniquely determined, but as an example, PD max Change the default value of -62dBm, PD min The default value of the PD may be set to -82 dBm. max and P.D. min You may change either or both of the PD for direct communication corresponding to a certain color index. max and P.D. min You may change either or both of these settings. max or PD min As a way to change PD max or PD minThe value of may be changed by directly specifying it, or may be changed by specifying an offset value for the default value. The base station device 1-1 may notify the terminal device of information indicating whether to use the default value or the changed value by broadcast communication, multicast communication, or unicast communication. As an example, the Spatial Reuse Parameter Set element may be extended to generate information for notifying the intra-BSS SR parameters together with the inter-BSS SR parameter set. FIG. 15(a) shows an example of the outline of the structure of an extended Spatial Reuse Parameter Set element (hereinafter, extended Spatial Reuse Parameter Set element). 1501 is an element ID, 1503 is an element ID extension, and these two fields identify the type of information element. 1502 is a length field indicating the length of the entire information element. 1504 is an SR control field, which includes information indicating, for example, whether PSR-based SR is not permitted as inter-BSS SR, whether Non-SRG OBSS PD SR is not permitted as inter-BSS SR, whether a Non-SRG Offset field for inter-BSS SR exists, whether an SRG information field for inter-BSS SR exists, whether a specific value is used in the SIG field, and whether a control field for intra-BSS SR is included. 1505 is a Non-SRG Offset field, which may not exist depending on the value of the SR control field. 1506 is an SRG OBSS PD Min Offset field, 1507 is an SRG OBSS PD Max Offset field, 1508 is an SRG BSS Color Bitmap, and 1509 is an SRG Partial BSSID Bitmap, which may not exist depending on the value of the SR control field 1504. 1510 is a control field for intra-BSS SR, which may not exist depending on the value of the SR control field 1504.The intra-BSS SR control field 1510 includes information indicating whether PSR-based SR is not recognized as intra-BSS SR, whether PD-based SR is not recognized as intra-BSS SR, whether bitmap information (Intra-BSS Color Bitmap1) corresponding to offset information applied to PDmin referenced when performing PD-based SR with intra-BSS SR exists, and whether bitmap information (Intra-BSS Color Bitmap2) corresponding to offset information applied to PDmax referenced when performing PD-based SR with intra-BSS SR exists. 1511 is bitmap information, and each bit of the 8 octets (=64 bits) indicates which color index the PDmin offset value is set for. The lowest bit corresponds to color index 0, and the highest bit corresponds to color index 63. When the bit value is 0, it indicates that the PDmin offset value is not set for the corresponding color index, and when the bit value is 1, it indicates that the PDmin offset value is set for the corresponding color index. 1512 is bitmap information, and each bit of the 8 octets indicates which color index the PDmax offset value is set for. The lowest bit corresponds to color index 0, and the highest bit corresponds to color index 63. When the bit value is 0, the PDmax offset value is not set for the corresponding color index, and when the bit value is 1, the PDmax offset value is set for the corresponding color index. 1513 to 1518 are fields containing the PDmin and PDmax offset values ​​set for the color index. In the example shown in FIG. 15(a), both the PDmin offset value and the PDmax offset value are arranged in ascending order of color index, but the PDmin offset value may be arranged in the order of color index, and then the PDmax offset value may be arranged in the order of color index. Also, the color index may be arranged in ascending or descending order.In this embodiment, a color index is set for PD-based intra-BSS SR, and a field is prepared in which the offset value is set to 0 when no offset is applied to PDmax or PDmin, but as a modified example, a bitmap indicating whether PD-based intra-BSS SR is executed for each color index and a bitmap indicating whether offset values ​​of PDmin and PDmax used when executing PD-based intra-BSS SR are set may be provided separately. Also, a bitmap indicating whether PSR-based intra-BSS SR is executed for each color index may be provided.

[0099] After updating the extended spatial reuse parameter set element, the base station device 1-1 may transmit the extended spatial reuse parameter set element to one or more terminal devices connected to the base station device 1-1 by broadcast communication, multicast communication, or unicast communication. At this time, the base station device 1-1 may also transmit a color index information element.

[0100] Once PDmin or PDmax, which is referred to when performing PD-based SR in intra-BSS SR, is set, it may be desired to change the power detection level, i.e., the setting of PDmin or PDmax, due to a change in the position of the terminal device for which direct communication is set or the surrounding radio wave propagation environment. In such a case, the terminal device may request the base station device to change either or both of PDmin and PDmax set for the set direct communication. An example of a flow related to this request is shown in FIG. 16. In this example, the terminal device 2-1 requests the base station device 1-1 to change the power detection level. 2401 is an Intra-BSS SR PD level change message transmitted from the terminal device 2-1 to the base station device 1-1. The terminal device 2-1 may include in the Intra-BSS SR PD level change message 2401 the offset value of PDmin after the change, or the offset value of PDmax after the change, or information for the base station device 1-1 to determine the offset value of PDmin or the offset value of PDmax, for example, information indicating the path loss between the terminal device 2-1 and the terminal device 2-2. Furthermore, the terminal device 2-1 may include in the Intra-BSS SR PD level change message 2401 the color index assigned to the currently set direct communication, the MAC address of the terminal device 2-1 corresponding to the currently set direct communication, and the MAC address of the other terminal device of the direct communication. After receiving the Intra-BSS SR PD level change message 2401, the base station device 1-1 may transmit the IntraBSS-SR announcement 2402 including the updated extended Spatial Reuse Parameter Set element to one or more terminal devices connected to the base station device 1-1 by broadcast communication, multicast communication, or unicast communication. At this time, a color index information element may also be transmitted.

[0101] As a method for exchanging capability information when a terminal device sets up direct communication with another terminal device, an example of exchanging capability information related to intra-BSS SR in a series of direct link setup procedures has been shown, but the exchange of capability information related to intra-BSS SR may be performed by another method. As an example, a case where capability information related to intra-BSS SR is exchanged in a direct link discovery procedure is shown. FIG. 13(c) is an example of a direct link discovery procedure. Here, a case where the terminal device 2-1 starts a direct link discovery procedure and the terminal device 2-2 responds to it is shown. First, the terminal device 2-1 transmits a direct link discovery request to the terminal device 2-2 via the base station device 1-1. 2121 is a direct link discovery request directed to the base station device, and 2122 is a direct link discovery request directed to the terminal device 2-2. After receiving the direct link discovery request 2122, the terminal device 2-2 transmits a direct link discovery response 2123 to the terminal device 2-1. The terminal device 2-1 can include capability information regarding the intra-BSS SR of the terminal device 2-1 in the direct link discovery requests 2121 and 2122, and the terminal device 2-2 can include capability information regarding the intra-BSS SR in the direct link discovery response 2123.

[0102] Next, a procedure for canceling direct communication corresponding to intra-BSS SR will be described. FIG. 13(a) shows an example of a flow for canceling direct communication corresponding to intra-BSS SR. In this flow, direct communication corresponding to intra-BSS SR set between terminal device 2-1 and terminal device 2-2 is canceled. First, terminal device 2-1 transmits a direct link teardown (direct communication cancellation) to terminal device 2-2 via base station device 1-1. 2101 is a direct link teardown directed to base station device 1-1, and 2012 is a direct link teardown directed to terminal device 2-2. In the case of canceling direct communication not corresponding to conventional intra-BSS SR, when a terminal device transmits a direct communication cancellation to another terminal device, it determines whether to communicate directly or via a base station device. As an example, when a direct communication cancellation is sent directly to another terminal device and an error occurs, it is determined that the direct communication cancellation is to be sent via the base station device. In this embodiment, however, when canceling direct communication corresponding to intra-BSS SR, the terminal device 2-1 transmits direct link teardowns 2101 and 2102 to the terminal device 2-2 via the base station device 1-1 without determining whether to transmit directly to the terminal device 2-2 or via the base station device 1-1. At this time, the terminal device 2-1 may include color index information corresponding to the direct link teardowns 2101 and 2102. The terminal device 2-2 that receives the direct link teardown 2102 cancels the setting of the direct communication set with the terminal device 2-1, and the terminal device 2-1 that confirms the delivery of the direct link teardowns 2101 and 2102 cancels the setting of the direct communication set with the terminal device 2-2.

[0103] After receiving the direct link teardown 2101, the base station device determines whether the direct communication that the direct link teardown 2101 is trying to resolve supports intra-BSS SR based on the source and destination of the direct link teardown 2101 or the color index included in the direct link teardown 2101, and if the direct communication that the direct link teardown 2101 is trying to resolve supports intra-BSS SR, it deletes the extended spatial reuse parameter set element and the information related to the direct communication that the direct link teardown 2101 is trying to resolve from the color index information element. As an example, it sets the bit corresponding to the color index linked to the direct communication that the direct link teardown 2101 is trying to resolve in the Intra-BSS Color Bitmap field of the color index information element to 0, and deletes the MAC address field corresponding to the bit set to 0. Furthermore, the bits corresponding to the color indexes linked to the direct communication that the direct link teardown 2101 is attempting to resolve in the Intra-BSS Color Bitmap1 field and the Intra-BSS Color Bitmap2 field of the extended spatial reuse parameter set element are set to 0, and the Intra-BSS PD Min field or the Intra-BSS PD Max field corresponding to the bits set to 0 is deleted. After deleting and updating the information related to the direct communication that the direct link teardown 2101 is attempting to resolve from the extended spatial reuse parameter set element and the color index information element, the base station device 1-1 may transmit an IntraBSS-SR announce message 2103 including either or both of the extended spatial reuse parameter set element and the color index information element to one or more terminal devices.

[0104] Next, an example of a flow when performing intra-BSS SR in a BSS will be described. As a premise, it is assumed that the setting flow described using FIG. 12 is executed, intra-BSS SR compatible direct communication is set between the terminal device 2-1 and the terminal device 2-2, and intra-BSS SR compatible direct communication is set between the terminal device 2-3 and the terminal device 2-4. In addition, it is assumed that the SR link information is shared by the extended spatial reuse parameter set element and the color index information element information transmitted from the base station device 1-1 to the terminal device 2-1 to the terminal device 2-4. It is assumed that the color index associated with the direct communication between the terminal device 2-1 and the terminal device 2-2 is 1, the color index associated with the direct communication between the terminal device 2-3 and the terminal device 2-4 is 2, the color index 1 indicates the terminal device 2-1 and the terminal device 2-2, and the color index 2 indicates the terminal device 2-3 and the terminal device 2-4. It is also assumed that the offset values ​​of PDmin and PDmax corresponding to color index 1 and the offset values ​​for PDmin and PDmax corresponding to color index 2 are set by the extended Spatial Reuse Parameter Set element. In this state, an example will be described with reference to Fig. 17 in which direct communication is performed from terminal device 2-1 to terminal device 2-2, and terminal device 2-3 performs SR for direct communication with terminal device 2-4 in response to this direct communication.

[0105] First, a case where PD-based SR is performed will be described. Reference numeral 2201 denotes transmission of a wireless frame from terminal device 2-1 to terminal device 2-2. Reference numeral 2202 denotes a PHY header including a SIG field of this wireless frame to be transmitted, and reference numeral 2203 denotes a data frame following PHY header 2202. Terminal device 2-1 includes color index 1 in the SIG field in PHY header 2202. Terminal device 2-1 may also include the BSS Color received from base station device 1-1 in the SIG field in PHY header 2202.

[0106] The terminal device 2-3 has transmission data addressed to the terminal device 2-4, but detects the wireless frame that the terminal device 2-1 transmits to the terminal device 2-2 and does not start transmission. This state is called CCA busy. After that, the terminal device 2-3 receives the PHY header 2202 that the terminal device 2-1 transmits to the terminal device 2-2, and checks the color index included in the PHY header. Since this color index is 1, the terminal device 2-3 identifies that the wireless frame being received is a direct communication between the terminal device 2-1 and the terminal device 2-2 based on the information included in the color index information element received from the base station device 1-1. The terminal device 2-1 and the terminal device 2-2 determine that the wireless frame is not addressed to the terminal device 2-4, which is the destination of the transmission data to be transmitted, and is not addressed to the terminal device 2-3, and the terminal device 2-3 moves on to judging the reception power of the wireless frame being received. The terminal device 2-3 sets the transmission power when transmitting data to the terminal device 2-4. Various methods can be used as a method for setting this transmission power. As an example, a method of setting based on the path loss between the terminal device 2-3 and the terminal device 2-4 measured using a direct link discovery procedure performed by the terminal device 2-3 for the terminal device 2-4 may be used. Using this set transmission power, the power detection level is calculated using (Equation 1). When calculating this power detection level, the terminal device 2-3 uses PDmin and PDmax corresponding to the color index 1 obtained from the information included in the extended spatial reuse parameter set element received from the base station device 1-1. The terminal device 2-3 measures the reception power using the PHY header 2202 transmitted by the terminal device 2-1 to the terminal device 2-2, and executes a CCA reset when the measured reception power falls below the power detection level calculated using (Equation 1). This releases the CCA busy of the terminal device 2-3, and the terminal device 2-3 transmits data 2205 to the terminal device 2-4. Regarding the wireless frame 2206 transmitted in this data transmission 2205, the terminal device 2-3 may complete the transmission of the wireless frame 2206 before the transmission of the wireless frames 2202 and 2204 transmitted by the terminal device 2-1 to the terminal device 2-2 is completed.Furthermore, when the terminal device 2-3 checks the color index included in the PHY header, if one of the two terminal devices linked to the color index is the terminal device 2-3 or the terminal device 2-4, it does not need to perform a CCA reset while the wireless frame is being received, regardless of the reception power of the wireless frame being received. Furthermore, if the PHY header 2202 of the wireless frame being received contains information that does not allow intra-BSS SR, the terminal device 2-3 does not need to perform a CCA reset while the wireless frame is being received. If the PHY header 2202 of the wireless frame being received does not contain information that does not allow intra-BSS SR and the terminal device linked to the color index and the reception power satisfy the above-mentioned conditions, the terminal device 2-3 may perform a CCA reset. Furthermore, when determining whether to perform a CCA reset, it may also be confirmed that the BSS Color included in the PHY header 2202 is the same as the BSS Color received by the terminal device 2-3 from the base station device 1-1.

[0107] Next, a case where PSR-based SR is performed will be described. The flow will be described with reference to FIG. 17. A wireless frame is transmitted from terminal device 2-1 to terminal device 2-2 (2201). 2202 is a PHY header including a SIG field of this wireless frame to be transmitted, and 2203 is a data frame following PHY header 2202. Terminal device 2-1 includes color index 1 and information indicating a PSR value in the SIG field in PHY header 2202. The information indicating the PSR value can be in various formats, but as an example, the PSR value itself or an index corresponding to the PSR value can be used.

[0108] The terminal device 2-3 has transmission data addressed to the terminal device 2-4, but it detects the wireless frame transmitted by the terminal device 2-1 to the terminal device 2-2 and does not start transmission. Subsequently, the terminal device 2-3 receives the PHY header 2202 transmitted by the terminal device 2-1 to the terminal device 2-2, and checks the color index and the information indicating the PSR value included in the PHY header. Since this color index is 1, based on the information included in the color index information element received from the base station device 1-1, it is identified that the received wireless frame is a direct communication between the terminal device 2-1 and the terminal device 2-2. It is determined that the terminal devices 2-1 and 2-2 are not the destination of the transmission data scheduled to be transmitted, which is the terminal device 2-4, nor are they addressed to the terminal device 2-3. Then, the terminal device 2-3 proceeds to determine the reception power of the received wireless frame. The terminal device 2-3 sets the transmission power when transmitting data to the terminal device 2-4. Various methods can be used for this method of setting the transmission power. As an example, a method such as setting based on the path loss between the terminal device 2-3 and the terminal device 2-4 measured using the direct link discovery procedure performed by the terminal device 2-3 for the terminal device 2-4 can be used. Using this set transmission power, the PSR opportunity is identified using the PSR value obtained from the information indicating the PSR value. The terminal device 2-3 measures the reception power using the PHY header 2202 transmitted by the terminal device 2-1 to the terminal device 2-2, and identifies the PSR opportunity when the reception power, PSR value, and transmission power satisfy a certain relationship. Various formats can be used for this relationship. As an example, when the following relational expression is satisfied, it is identified as the PSR opportunity. Transmission power < PSR value - Reception power ···(Equation 2) When the PSR opportunity is identified, the terminal device 2-3 performs data transmission 2205 to the terminal device 2-4 as it has obtained a transmission opportunity. With regard to the wireless frame 2206 transmitted in the data transmission 2205, the terminal device 2-3 may end the transmission of the wireless frame 2206 before the transmission of the wireless frames 2202 and 2204 transmitted by the terminal device 2-1 to the terminal device 2-2 is ended. Furthermore, when the terminal device 2-3 checks the color index included in the PHY header, if one of the two terminal devices linked to the color index is the terminal device 2-3 or the terminal device 2-4, it is not necessary to identify the PSR opportunity while the wireless frame is being received, regardless of the reception power of the wireless frame being received. Furthermore, if the PHY header 2202 of the wireless frame being received includes information not permitting intra-BSS SR, the terminal device 2-3 is not necessary to identify the PSR opportunity while the wireless frame is being received. When the PHY header 2202 of the wireless frame being received does not include information not allowing intra-BSS SR and the terminal device linked to the color index, the received power, and the PSR value satisfy the above-mentioned conditions, the terminal device 2-3 may identify the PSR opportunity. When identifying the PSR opportunity, it may also be confirmed that the BSS Color included in the PHY header 2202 is the same as the BSS Color received by the terminal device 2-3 from the base station device.

[0109] Up to this point, a case has been described in which PD-based SR and PSR-based SR are performed for multiple direct communications as intra-BSS SR. Intra-BSS SR is not limited to multiple direct communications, but can also be performed for communications between a base station device and a terminal device. An example of PSR-based SR will be described with reference to FIG. 18. FIG. 18 shows an example in which the base station device 1-1, which has received a direct communication 2301 sent from the terminal device 2-1 to the terminal device 2-2, performs SR on the terminal device 2-5. The base station device 1-1 receives the PHY header 2302 of the direct communication 2301 sent from the terminal device 2-1 to the terminal device 2-2, and holds off on transmission to the terminal device 2-5. The base station device 1-1 may use the color index and information indicating the PSR value included in the received PHY header to determine that the direct communication 2301 is not related to the base station device 1-1 and the other party of the pending communication, and may determine whether the PSR value calculated from the information indicating the PSR value and the relationship between the reception power and transmission power of the PHY header satisfy (Equation 2). If they do, the base station device 1-1 may determine that a PSR opportunity has been identified, and may perform a transmission 2305 using SR to the terminal device 2-5. At this time, the base station device 1-1 may adjust the length of the data section 2306 of the transmission 2305 to the terminal device 2-5 so that it fits within the length of the data section 2303 transmitted by the terminal device 2-1 to the terminal device 2-2. In addition, when identifying the PSR opportunity, it may also determine that the BSS Color included in the PHY header 2302 indicates a BSS managed by the base station device 1-1. In addition, the same can be performed for PD-based SR instead of PSR-based SR.

[0110] By operating as described above, it is possible to improve communication efficiency within the BSS by acquiring a new transmission opportunity while another terminal device is transmitting. In addition, it is possible to establish communication between a plurality of pairs by using the power of the radio frame being transmitted when the transmission opportunity is acquired and other set conditions. In the present embodiment, an example is shown in which intra-BSS SR is executed between a base station device and a terminal device that have exchanged capability information related to intra-BSS SR, but other information may be referred to when executing intra-BSS SR. As an example, intra-BSS SR may be executed for data used by a certain type of application, such as high-priority traffic and traffic specified for low latency. This makes it possible to improve communication efficiency in cooperation with the application. [2. Common to all embodiments]

[0111] The communication device according to the present invention can communicate in a frequency band (frequency spectrum) called an unlicensed band, which does not require permission to use from a country or region, but the available frequency band is not limited to this. The communication device according to the present invention can also be effective in a frequency band called a white band (for example, a frequency band allocated for television broadcasting but unused in some regions) that is not actually used for the purpose of preventing interference between frequencies even though permission to use the band for a specific service is given by a country or region, and in a shared spectrum (shared frequency band) that is expected to be shared by multiple operators.

[0112] The program that operates in the wireless communication device according to the present invention is a program that controls the CPU, etc. (a program that makes a computer function) so as to realize the functions of the above-mentioned embodiments of the present invention. Information handled by these devices is temporarily stored in the RAM during processing, and then stored in various ROMs or HDDs, and is read, modified, and written by the CPU as necessary. The recording medium that stores the program may be any of semiconductor media (e.g., ROM, non-volatile memory card, etc.), optical recording media (e.g., DVD, MO, MD, CD, BD, etc.), magnetic recording media (e.g., magnetic tape, flexible disk, etc.), etc. In addition, not only the functions of the above-mentioned embodiments are realized by executing the loaded program, but also the functions of the present invention may be realized by processing in cooperation with an operating system or other application programs, etc. based on instructions from the program.

[0113] In addition, when distributing the program on the market, the program can be stored in a portable recording medium and distributed, or transferred to a server computer connected via a network such as the Internet. In this case, the storage device of the server computer is also included in the present invention. In addition, a part or all of the communication device in the above-mentioned embodiment may be realized as an LSI, which is typically an integrated circuit. Each functional block of the communication device may be individually formed into a chip, or a part or all of the functional blocks may be integrated into a chip. When each functional block is formed into an integrated circuit, an integrated circuit control unit that controls them is added.

[0114] In addition, the method of integration is not limited to LSI, but may be a dedicated circuit or a general-purpose processor. In addition, if an integrated circuit technology that can replace LSI appears due to the advancement of semiconductor technology, it is also possible to use an integrated circuit based on that technology.

[0115] The present invention is not limited to the above-mentioned embodiment. The wireless communication device of the present invention is not limited to application to a mobile station device, but can be applied to stationary or non-movable electronic devices installed indoors or outdoors, such as AV equipment, kitchen equipment, cleaning and washing machines, air conditioners, office equipment, vending machines, and other household appliances.

[0116] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and designs and the like that do not deviate from the gist of the present invention are also included in the scope of the claims. [Industrial Applicability]

[0117] The present invention is suitable for use in a communication device and a communication method. [Explanation of symbols]

[0118] 1-1, 1-2, 2-1~2-6, 2A, 2B Wireless communication equipment 3-1, 3-2 Management scope Sectors 7-1, 7-2, 7-3, 7-4 10-1 Wireless communication equipment 10001-1 Upper layer section 10002-1 (Independent distributed) control unit 10002a-1 CCA Department 10002b-1 Backoff section 10002c-1 Transmission decision unit 10003-1 Transmitter 10003a-1 Physical layer frame generator 10003b-1 Radio transmitter 10004-1 Receiver 10004a-1 Radio receiver 10004b-1 Signal demodulation section 10004c-1 Evaluation section 10005-1 Antenna section 100-1, 100-3, 100-6, 100-11 Busy 100-4, 100-7 random backoff 100-2, 100-5, 100-8, 100-10 radio frames 1401,1421 Radio Frames

Claims

1. The first terminal device, A receiving unit that receives the received frame, A transmitting unit that transmits a transmission frame, Equipped with, It communicates with the base station equipment and directly communicates with the second terminal equipment. The transmitting / receiving unit transmits the transmission frame, which includes setting information for direct communication between the first terminal device and the second terminal device, to the base station device. The receiving unit receives the received frame from the base station device, which includes an identifier relating to direct communication between the first terminal device and the second terminal device. The identifier relating to the direct communication is generated by the base station device based on the transmission frame transmitted from the first terminal device and is used for direct communication with the second terminal device. The first terminal device.

2. A wireless communication method used in a first terminal device, Received a frame, Send the transmission frame, It communicates with the base station equipment, Direct communication is established with the second terminal device. The base station device receives the transmission frame containing the setting information for direct communication between the first terminal device and the second terminal device. The base station device receives the received frame, which includes an identifier relating to direct communication between the first terminal device and the second terminal device. The identifier relating to the direct communication is generated by the base station device based on the transmission frame transmitted from the first terminal device and is used for direct communication with the second terminal device. Wireless communication method.

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