Wireless communication device and communication method

Abstract

A wireless communication device comprising: a reception unit for receiving an Inter BSS PPDU; a transmission unit for transmitting a PSRTPPDU; and a control unit provided with the capability of configuring both configured dRU configurations. When the dRU configurations are set to the PSRT PPDU, the maximum transmission power set for the PSRT PPDU is set on the basis of the reception power of the Inter BSS PPDU, a first parameter acquired from the Inter BSS PPDU, and the number of first subcarriers per MHz, the first subcarrier being a subcarrier constituting the PSRT PPDU.

Description

Wireless communication device and communication method

[0001] This application claims priority to Japanese Patent Application No. 2024-130165, filed Aug. 6, 2024, the contents of which are incorporated herein by reference.

[0002] The Institute of Electrical and Electronics Engineers Inc. (IEEE) continues to update the specifications of the wireless LAN (Local Area Network) standard, IEEE 802.11, to achieve faster wireless LAN communications and more efficient frequency utilization. Wireless LANs enable wireless communication using unlicensed frequency bands, which can be used without a license from a national or regional authority. For personal use, such as at home, wireless Internet access from within a home has become possible by incorporating a wireless LAN access point function into 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 to the line termination device. This allows wireless LAN station devices, such as smartphones and personal computers, to connect to the wireless LAN access point device and access the Internet.

[0003] The IEEE 802.11ax standard was completed in 2021, and wireless LAN devices compliant with this standard, as well as communication devices such as smartphones and personal computers equipped with such wireless LAN devices, have appeared on the market as Wi-Fi 6 (a registered trademark, the name for IEEE 802.11ax-compliant products certified by the Wi-Fi Alliance). Currently, standardization activities for IEEE 802.11be, the successor standard to IEEE 802.11ax, are underway, and discussions are also underway for its successor, IEEE 802.11bn. With the rapid spread of wireless LAN devices, recent IEEE 802.11 standardization efforts are being considered to further improve throughput per user in environments where wireless LAN devices are densely deployed.

[0004] In the IEEE 802.11be standardization, discussions are underway regarding multi-link operation (MLO), which enables wireless communication devices to simultaneously maintain multiple link connections using multiple frequency bands, channels, etc. (see Non-Patent Document 1). One example of MLO is the simultaneous operation of three link connections in different frequency bands: a 2.4 GHz band connection, a 5 GHz band (5.2 GHz band, 5.3 GHz band, 5.6 GHz band, etc.), and a 6 GHz band connection. Of course, the combinations of frequency bands, channels, etc. are not limited to these, and various combinations are possible. In terms of frequency bands, in the future, high-frequency bands such as millimeter waves (28 GHz band, 45 GHz band, 60 GHz band, etc.) and (sub)terahertz waves (100 GHz to 300 GHz band) may also be used as one link constituting a multi-link. MLO allows wireless communication devices to simultaneously maintain multiple link connections using different wireless resources and communication settings. A wireless communication device can not only transmit and receive frames using multiple links simultaneously, but also switch the link connections for transmitting and receiving frames, i.e., change the frequency band, without performing a reconnection operation. Note that each link constituting a multilink is also called a physical layer link. A wireless communication device that supports MLO is called a multi-link device (MLD).

[0005] Furthermore, in the IEEE 802.11bn standardization, in order to expand the communication range, discussions are being held on a distributed resource unit (dRU), which discretely arranges subcarriers (tones) that have previously been arranged continuously (Non-Patent Document 2). In a wireless LAN where communication is generally performed in an unlicensed band, if the maximum transmit power is specified based on the occupied bandwidth of the signal, discretely allocating tones makes it possible to set a higher maximum transmit power than when the tones are arranged continuously. In other words, the introduction of dRUs improves the communication range of wireless LAN devices.

[0006] IEEE 802.11-19 / 0773-08-00be, Nov. 2019IEEE 802.11-24 / 0882r2, May 2024

[0007] In a wireless LAN, it is necessary to maintain backward compatibility to support conventional communication standards, so if dRU is implemented, wireless communication devices that implement the conventional method of consecutively arranging tones (rRU: regular resource unit) will coexist with wireless communication devices that implement dRU. In an environment where many wireless communication devices exist, the exposed terminal problem reduces the rate of obtaining communication opportunities, but there is a problem that the signal transmitted by the dRU has a longer propagation distance than the signal transmitted by the rRU, which accentuates the exposed terminal problem.

[0008] The wireless communication device and communication method according to the present invention for solving the above-mentioned problems are as follows.

[0009] (1) That is, a wireless communication device according to one aspect of the present invention includes a receiver that receives an Inter BSS (Basic Service Set) PPDU (PHY Protocol Data Unit), a transmitter that transmits a PSRT (Parameterized Spatial Reuse Transmission) PPDU, and a controller that is capable of configuring both a dRU (Distributed Resource Unit) configuration consisting of a plurality of subcarriers spread across a predetermined bandwidth, wherein when the dRU configuration is configured in the PSRT PPDU, a maximum transmit power that is configured in the PSRT PPDU is set based on the received power of the Inter BSS PPDU, a first parameter acquired from the Inter BSS PPDU, and a first number of subcarriers per 1 MHz, and the first subcarriers are subcarriers that configure the PSRT PPDU.

[0010] (2) Furthermore, in a wireless communication device according to one aspect of the present invention, the control unit is further configured to configure an rRU (regular resource unit) configuration consisting of a plurality of subcarriers arranged adjacently, the first parameter obtained from the Inter BSS PPDU is obtained from a numerical value written in a predetermined field included in the Inter BSS PPDU, the numerical value written in the predetermined field and the first parameter are associated with a first table and a second table, and when setting the dRU configuration in the PSRT PPDU, the first table is referenced, and when setting the rRU configuration in the PSRT PPDU, the second table is referenced.

[0011] (3) Furthermore, a wireless communication device according to one aspect of the present invention is described in (1) above, wherein the control unit further has the ability to configure an rRU (regular resource unit) configuration consisting of multiple adjacently arranged subcarriers, and when the dRU configuration is set in the Inter BSS PPDU, the control unit sets the dRU configuration in the PSRT frame, and when the rRU configuration is set in the Inter BSS PPDU, the control unit sets the rRU configuration in the PSRT PPDU.

[0012] (4) Furthermore, a communication method according to one aspect of the present invention is a communication method for a wireless communication device, comprising the steps of receiving an Inter BSS (Basic Service Set) PPDU (PHY Protocol Data Unit), transmitting a PSRT (Parameterized Spatial Reuse Transmission) PPDU, and configuring both a dRU (Distributed Resource Unit) configuration consisting of a plurality of subcarriers spread across a predetermined bandwidth, wherein when the dRU configuration is configured in the PSRT PPDU, a maximum transmit power set in the PSRT PPDU is set based on the received power of the Inter BSS PPDU, a first parameter acquired from the Inter BSS PPDU, and a first number of subcarriers per 1 MHz, and the first subcarriers are subcarriers that configure the PSRT PPDU.

[0013] According to the wireless communication device and communication method of the present invention, even when wireless communication devices using dRUs and rRUs are mixed, the exposed terminal problem is not circumvented and the rate of obtaining communication opportunities is improved, thereby contributing to improving frequency utilization efficiency.

[0014] FIG. 1 is a diagram showing an example of a MAC layer frame configuration related to a wireless LAN system. FIG. 2 is a diagram showing an example of a PPDU configuration related to a wireless LAN system. FIG. 3 is a diagram showing an example of a sounding procedure related to a wireless LAN system. FIG. 4 is a diagram showing an example of a configuration of a communication system according to an aspect of the present invention. FIG. 5 is a block diagram showing an example of a configuration of a station device according to an aspect of the present invention. FIG. 6 is a block diagram showing an example of a configuration of an access point device according to an aspect of the present invention. FIG. 7 is a diagram showing an example of a configuration of a communication system according to an aspect of the present invention. FIG. 8 is a diagram showing an example of a signal configuration related to an aspect of the present invention. FIG. 9 is a diagram showing an example of a signal configuration related to an aspect of the present invention. FIG. 10 is a diagram showing an example of a table referenced by a wireless communication device according to an aspect of the present invention. FIG. 11 is a diagram showing an example of a table referenced by a wireless communication device according to an aspect of the present invention.

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

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

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

[0018] A PHY layer frame is called a physical protocol data unit (PPDU, PHY layer frame). A PPDU is composed of a physical layer header (PHY header) containing information for signal processing in the physical layer, and a physical service data unit (PSDU, PHY service data unit), which is a data unit processed in the physical layer. A PSDU can be composed of an aggregated MPDU (A-MPDU), which aggregates multiple MAC protocol data units (MPDU, MAC layer frames), which serve as retransmission units in wireless sections.

[0019] The PHY header includes reference signals such as a short training field (STF) used for signal detection and synchronization, and a long training field (LTF) used to acquire channel information for data demodulation, as well as control signals such as a signal (SIG) containing control information for data demodulation. Furthermore, STF is classified into Legacy-STF (L-STF), High Throughput-STF (HT-STF), Very High Throughput-STF (VHT-STF), High Efficiency-STF (HE-STF), Extremely High Throughput-STF (EHT-STF), etc. depending on the corresponding standard, and LTF and SIG are similarly classified into L-LTF, HT-LTF, VHT-LTF, HE-LTF, L-SIG, HT-SIG, VHT-SIG, HE-SIG, and EHT-SIG. VHT-SIG is further classified into VHT-SIG-A1, VHT-SIG-A2, and VHT-SIG-B. Similarly, HE-SIG is classified into HE-SIG-A1 to HE-SIG-A4 and HE-SIG-B. In addition, a Universal SIGNAL (U-SIG) field containing additional control information may be included, assuming technology updates within the same standard.

[0020] Furthermore, the PHY header can include information for identifying the BSS that is the sender of the frame (hereinafter also referred to as BSS identification information). The information for identifying the BSS can be, for example, the SSID (Service Set IDentifier) ​​of the BSS or the MAC address of the access point device of the BSS. The information for identifying the BSS can also be a value unique to the BSS (for example, a BSS Color) other than the SSID or MAC address. Information indicating the BSS Color can be included in the HE-SIG-A or U-SIG.

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

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

[0023] Frame types in the MAC layer are broadly classified into three types: management frames that manage the connection status between devices, control frames that manage the communication status between devices, and data frames that contain actual transmission data. Each type is further classified into multiple subframe types. Control frames include acknowledgement (Ack or ACK) frames, block acknowledgement (BA or BlockAck) frames, request to send (RTS) frames, and clear to send (CTS) frames. BlockAck can acknowledge (notify completion of reception) multiple MPDUs. Management frames include beacon frames, probe request frames, probe response frames, authentication frames, association request frames, and association response frames. Data frames include data frames and polling (CF-poll) frames. Each device can recognize the frame type and subframe type of a received frame by reading the contents of the frame control field included in the MAC header.

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

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

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

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

[0028] First, an example of the operation when an access point device transmits a signal to a station device based on DCF will be described. In DCF, the access point device and the station device perform carrier sense (CS) to check the usage status of the wireless channel around the device before communication. For example, if the access point device or the station device that is about to transmit a frame receives a signal with a received power higher than a predetermined clear channel assessment level (CCA level) on the wireless channel during the carrier sense period performed prior to transmission, the access point device or the station device postpones the transmission of the frame on the wireless channel. Hereinafter, a state in which a signal with a received power equal to or higher than the CCA level is detected on the wireless channel is referred to as a busy state, and a state in which a signal with a received power equal to or higher than the CCA level is not detected is referred to as an idle state. In this way, CS performed by each device based on the power level of the signal actually received is referred to as physical carrier sense (physical CS). The CCA level is also referred to as the carrier sense level (CS level) or the CCA threshold (CCAT). When the access point device and station device detect a signal with a reception power equal to or higher than the CCA level, they begin to demodulate at least the PHY layer signal.

[0029] An access point device performs carrier sensing during an interframe space (IFS) period set according to the type of frame to be transmitted, and determines whether the wireless channel is busy or idle. The period during which the access point device performs carrier sensing varies depending on the frame type and subframe type of the frame to be transmitted. The IEEE 802.11 system defines multiple IFS periods with different periods, including a short interframe space (SIFS) used for frames assigned the highest priority, a polling interframe space (PIFS: PCF IFS) used for frames with relatively high priority, and a distributed arbitration interframe space (DIFS: DCF IFS) used for frames with low priority. When transmitting data frames using DCF, the access point device uses the DIFS.

[0030] After waiting for the DIFS period, the access point device further waits for a random backoff time to prevent frame collisions. In the IEEE 802.11 system, a random backoff time based on a contention window (CW) is used. CSMA / CA assumes that a frame transmitted by a transmitting station is received by a receiving station without interference from other transmitting stations. Therefore, if multiple transmitting stations transmit frames at the same time, the frames may collide with each other, potentially preventing the receiving station from receiving the frames correctly. Therefore, frame collisions are avoided by each transmitting station waiting for a randomly set time before starting transmission. When the access point device determines that the wireless channel is idle through carrier sense, it starts counting down a backoff counter set based on the CW. Only when the backoff counter reaches 0 can it acquire the right to transmit and transmit a frame to the station device. If the access point device determines that the wireless channel is busy through carrier sense during the backoff counter countdown, it stops counting down the backoff counter. Then, when the wireless channel becomes idle again, the access point device waits for the same period as the previous IFS, and then resumes counting down the remaining part of the previous backoff counter.

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

[0032] If a station device determines that a received frame is addressed to itself and demodulates the frame without error, it must transmit an Ack frame to the access point device, which is the transmitting station, indicating that the frame was received correctly. The Ack frame is one of the highest-priority frames that is transmitted after waiting only an SIFS period (without a random backoff time). The access point device terminates a series of communications upon receiving the Ack frame from the station device. If the station device fails to receive a frame correctly, it will not transmit an Ack frame. Therefore, if the access point device does not receive an Ack frame from the receiving station (station device) within a certain period (SIFS + Ack frame length) after transmitting the frame, it will determine that the communication has failed and terminate the communication. Thus, the end of a single communication (also called a burst) in an IEEE 802.11 system is always determined by whether or not an Ack frame is received, except in special cases such as when a beacon frame or other notification signal is transmitted or when fragmentation is used to divide the transmitted data.

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

[0034] Next, an example of the operation when an access point device transmits a signal to a station device based on PCF will be described. Unlike DCF, in which each device performs carrier sensing and autonomously acquires the transmission right, in PCF, a control station called a Point Coordinator (PC) controls the transmission right of each device within the BSS. Generally, an access point device becomes the PC and acquires the transmission right of the station device within the BSS.

[0035] The communication period by PCF includes a contention-free period (CFP) and a contention period (CP). During the CP, communication is performed based on the DCF described above, and the PC controls the transmission right during the CFP. The access point device, which is the PC, broadcasts a beacon frame including information such as the CFP duration (CFP Max duration) within the BSS prior to PCF communication. Note that the beacon frame broadcast at the start of PCF transmission uses PIFS and is transmitted without waiting for the CW. A station device that receives the beacon frame sets the CFP Max duration included in the beacon frame in its NAV. Thereafter, until the period set in the NAV elapses or a signal announcing the end of the CFP (e.g., a data frame including CF-end) is received within the BSS, the station device can acquire the transmission right only when it receives a signal signaling acquisition of the transmission right for the device from the PC (e.g., a data frame including CF-poll). During the CFP period, no packet collisions occur within the same BSS, so each station device does not take the random backoff time used in DCF.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[0063] Next, an example will be described in which the access point device 4001 and the station device 4002 support multi-link operation (MLO), in which communication is performed simultaneously using two wireless links: a first wireless link and a second wireless link that uses a frequency band (or frequency channel) different from that of the first wireless link. Note that MLO is not limited to two wireless links, and multiple wireless links in different frequency bands (or frequency channels) can be used.

[0064] A multi-link device (MLD) is a device capable of multi-link communication through multi-link operation, and an access point device that supports MLO will be referred to as an MLD access point device, and a station device that supports MLO will be referred to as an MLD station device. Furthermore, MLD access point devices and MLD station devices will also be collectively referred to as MLD wireless communication devices. In this embodiment, the wireless communication devices 4001-1, 4001-2, 4002A, and 4002B described above will be described as MLD wireless communication devices, but in actual operation, not all wireless communication devices in a wireless communication system will necessarily support MLO.

[0065] The MLD access point device 10001 and the MLD station device 10002 will be described using FIG. 7 . The MLD wireless communication device is composed of multiple sub-wireless communication devices corresponding to the frequency bands (or frequency channels) of each wireless link (also referred to as a physical layer link) that constitutes the multilink. Each sub-wireless communication device may support all frequency bands (and frequency channels) supported by the MLD wireless communication device, or each may support only one of the frequency bands (or frequency channels). FIG. 8 shows an example in which the MLD access point device 10001 is composed of two sub-wireless communication devices, in this case, two sub-access point devices 10001-1 and 10001-2, and a multilink control unit 10011, but the number of sub-access point devices may be any number greater than or equal to two. Note that, hereinafter, when any one of the multiple sub-access point devices is described as a representative, it will be referred to as the sub-access point device 10001-N. 8 similarly shows an example in which the MLD station device 10002 is configured with two sub-wireless communication devices, in this case two substation devices 10002-1 and 10002-2, and a multi-link control unit 10012, but the number of substation devices may be any number greater than or equal to two. Note that, hereinafter, when any one of the multiple substation devices is described as a representative, it will be referred to as substation device 10002-N. Furthermore, the sub-wireless communication devices (sub-access point devices and substation devices) may be configured with some circuits within the wireless communication device, and may be referred to as sub-wireless communication units (sub-access point units, substation units).

[0066] 8 shows an example in which multiple sub-wireless communication devices are configured as logically separate blocks, but they may be physically configured as a single wireless communication device. Alternatively, multiple sub-wireless communication devices may be configured as physically separate devices. In this embodiment, a case in which each sub-wireless communication device is configured as a physically separate device will be described as an example.

[0067] The number of sub-access point devices included in one MLD access point device and the number of substation devices included in one MLD station device may vary depending on the grade, class, capabilities, etc. of each MLD wireless communication device. The higher the grade, class, and capabilities of an MLD wireless communication device, the greater the number of sub-wireless communication devices (sub-access point devices, substation devices) it may have. In other words, for each MLD wireless communication device present in a wireless communication system, the sub-wireless communication devices (sub-access point devices, substation devices) that make up each MLD wireless communication device may differ depending on the grade, class, capabilities, etc., and the numbers of these devices do not have to be the same.

[0068] The substation apparatus 10002-1 associates with the sub-access point apparatus 10001-1 and establishes a wireless link 10003-1 (first wireless link), and the substation apparatus 10002-2 associates with the sub-access point apparatus 10001-2 and establishes a wireless link 10003-2 (second wireless link).

[0069] The configuration of the sub-access point devices 10001-N in Fig. 7 is the same as the configuration of the access point device 4001 in Fig. 6, except that a multi-link control unit 10011 is connected to the wireless control unit 6001 of each sub-access point device 10001-N. The multi-link control unit 10011 controls the wireless links for each sub-access point device 10001-N and exchanges control information and transmitted / received data with each sub-access point device 10001-N. The multi-link control unit 10011 distributes transmitted data frames to the sub-access point devices 10001-1 and 10001-2, i.e., the wireless links 10003-1 and 10003-2, and aggregates received data frames from the sub-access point devices 10001-1 and 10001-2, i.e., the wireless links 10003-1 and 10003-2.

[0070] 7 is the same as the configuration of the station device 4002 in FIG. 5, except that a multilink control unit 10012 is connected to the wireless control unit 5001 of each substation device 10002-N. The multilink control unit 10012 controls the wireless links for each substation device 10002-N and exchanges control information and transmitted / received data with each substation device 10002-N. The multilink control unit 10012 distributes transmitted data frames to each of the substation devices 10002-1 and 10002-2, i.e., to each of the wireless links 10003-1 and 10003-2, and aggregates received data frames from each of the substation devices 10002-1 and 10002-2, i.e., to each of the wireless links 10003-1 and 10003-2.

[0071] In the following description, for the sake of simplicity, an example will be described in which the wireless links constituting the multilink are two, wireless link 10003-1 (first wireless link) and wireless link 10003-2 (second wireless link), but this is not limiting and the present invention is similarly applicable to a case in which the number of wireless links is three or more. Furthermore, an example will be described in which the frequency band of the first wireless link is 2.4 GHz and the frequency band of the second wireless link is 5 GHz, but the frequency band used by each wireless link can be set arbitrarily from frequency bands (or frequency channels) supported by the wireless communication system, such as the 2.4 GHz band, 5 GHz band, 6 GHz band, and 60 GHz band, and these frequency bands may change according to the laws and regulations of each country.

[0072] 8 and 9 are diagrams showing an example of the configuration of a transmission signal generated by a wireless communication device according to this embodiment. As described above, the wireless communication device according to this embodiment can use an orthogonal frequency division multiplexing (OFDM) signal as the modulated signal constituting the transmission frame. Furthermore, the wireless communication device (mainly an access point device) according to this embodiment can implement orthogonal frequency division multiple access (OFDMA), which divides a predetermined number of subcarriers (tones) constituting the OFDM signal into resource units (RUs) and assigns each RU to a wireless communication device (mainly a station device) under its control, thereby achieving simultaneous multiplexed transmission. The OFDMA transmission includes downlink OFDMA transmission in which an access point device transmits to multiple station devices, and uplink OFDMA transmission in which multiple station devices transmit to the access point device simultaneously (at the same timing) based on a trigger frame from the access point device. The wireless communication device and communication method according to this embodiment are not limited to a specific OFDMA transmission scheme, but the following description will be given taking as an example a state in which uplink OFDMA transmission (UL OFDMA) is being performed.

[0073] In OFDMA transmission, a wireless communication device (access point device) divides a communication band secured by carrier sensing to allocate the communication band to other wireless communication devices (station devices). The wireless communication device according to this embodiment divides the communication band based on RUs. FIG. 8 shows an example of a method for dividing the communication band according to this embodiment, in which the communication band is divided into RUs (rRUs) each consisting of contiguous tones. Meanwhile, FIG. 9 shows an example of a method for dividing the communication band according to this embodiment, in which the communication band is divided into RUs (dRUs) each consisting of discretely arranged tones. The wireless communication device according to this embodiment can be configured to enable either or both of the rRUs and dRUs. Furthermore, the number of tones constituting each rRU and the number of rRUs and dRUs to be allocated to the communication band are not limited. Note that, in a dRU according to this embodiment, at least one of the tones constituting the dRU is arranged farther away from the other tones than the frequency interval between adjacent tones. Meanwhile, in an rRU, all of the tones constituting the rRU are arranged adjacent to each other. For simplicity, the following description will be given taking as an example a case where the number of tones allocated per station device is the same for the dRU and the rRU.

[0074] In the rRU method shown in Figure 8, the wireless communication device according to this embodiment divides the reserved 20 MHz into nine RUs 801 to 809, with each RU consisting of 26 tones. The access point device can allocate the nine RUs to other station devices. The access point device can allocate one RU to one station device, or it can allocate multiple RUs to one station device.

[0075] 9, the wireless communication device according to this embodiment divides the reserved 20 MHz into nine RUs 901 to 909, but RU 901 is made up of RUs 901-1 and 901-2, and RUs 901-1 and 901-2 are each made up of 13 tones, so RU 901 and RU 801 have the same number of tones. The same is true for RUs 902 to 909.

[0076] In the station device according to this embodiment, the number of available tones is the same when an RU 801 consisting of a dRU is assigned and when an RU 901 consisting of an rRU is assigned. However, when transmitting an OFDM signal consisting of the assigned tones, the maximum transmission power that can be set for the OFDM signal differs. This is because the maximum transmission power that can be set for an OFDM signal in the wireless communication device according to this embodiment varies depending on the state of the occupied band of the OFDM signal. For example, consider a case in which the maximum transmission power per unit frequency in 10 MHz units is specified as 10 dBm for the station device according to this embodiment. In this case, if an RU 801, which is an rRU, is assigned to the station device, the RU 801 will set the maximum transmission power to 10 dBm because all tones are included in the 10 MHz bandwidth. On the other hand, when RU901, which is a dRU, is set in a station device, RU901-1 contains half of all tones transmitted in the lower 10 MHz frequency band of the entire communication bandwidth, while RU-901-2 contains the remaining half of all tones transmitted in the higher 10 MHz frequency band, so the station device can set 10 dBm as the maximum transmission power for each of RU901-1 and RU902-2, and therefore the station device can set a maximum transmission power for the OFDM signal formed using RU901 that is twice the maximum transmission power set for the OFDM signal formed using RU801. The above explanation has been given using an example of the number of tones constituting an RU, their arrangement, and a method for specifying the maximum transmission power, but it goes without saying that the wireless communication device and communication method according to this embodiment are not limited to this example setting method.

[0077] In a dRU according to this embodiment, multiple resource allocations with different periods for discretely allocated tones can be configured. For example, when a dRU is configured by periodically allocating tones one by one, multiple periods for allocating tones can be configured. The wireless communication device according to this embodiment can also change the period for allocating tones. The wireless communication device according to this embodiment can set information indicating the period for allocating tones (or the number of tones allocated per 1 MHz) in the PHY header of the PPDU to be transmitted. Furthermore, the wireless communication device according to this embodiment can notify other wireless communication devices of information indicating the period for allocating tones (or the number of tones allocated per 1 MHz) using information indicating the RU to be allocated. For example, when allocating an RU to another wireless communication device, the wireless communication device according to this embodiment can notify the other wireless communication device of the allocated RU by assigning a number to the RU and notifying the other wireless communication device of the number. Since different numbers are assigned to RUs with different periods for allocating tones, the wireless communication device according to this embodiment can notify the other wireless communication device of the tone period of the allocated RU.

[0078] In order to avoid the exposed terminal problem, the wireless communication device according to this embodiment can change reference parameters when performing channel access in CSMA / CA. Unlike normal carrier sense, when a received signal has a predetermined attribute, the wireless communication device according to this embodiment can enter channel access operation on the premise that a transmit power lower than a value calculated based on the received power of the received signal and information acquired from the received signal is used. Here, the channel access operation includes at least a random backoff operation. The channel access method is not limited to any particular method, but an example will be described below.

[0079] The wireless communication device according to this embodiment determines whether a received signal (received frame) is a received frame (Intra-BSS PPDU) transmitted from a BSS to which the device belongs or a received frame (Inter-BSS PPDU, OBSS PPDU, OBSS frame) transmitted from a BSS to which the device does not belong (OBSS: Overlapped BSS), and can change the CSMA / CA channel access method based on the result. Hereinafter, the channel access method implemented by the wireless communication device when the received frame is an OBSS frame will be referred to as spatial reuse (SR) operation.

[0080] The wireless communication device according to this embodiment can perform parameterized spatial reuse (PSR) operation as the SR operation. A frame transmitted by the wireless communication device based on the PSR operation is referred to as a PSRT PPDU (Parameterized Spatial Reuse Transmission, PSRT frame). In the PSR operation, the wireless communication device determines that a received frame is an OBSS frame, and if the received power of the received frame is RPL0, a parameter (first parameter) acquired from the OBSS frame is PSR0, and the maximum transmit power set in the PSRT PPDU is P0, the wireless communication device can begin transmitting the PSRT PPDU if P0 is smaller than the value obtained by subtracting RPL0 from PSR0. Note that P0 may be defined in dBm. Furthermore, P0 may be defined as a value obtained by subtracting the decibel value of the value obtained by dividing the bandwidth of the PSRT frame by PPDU_BW by 20 MHz.

[0081] In CSMA / CA, as a general rule, while a wireless communication device is transmitting, other wireless communication devices do not transmit frames to avoid frame collisions. On the other hand, even if station devices in adjacent BSSs simultaneously transmit frames to the access point devices managing their respective BSSs, the frames will interfere with the station devices in the adjacent BSSs, but will not necessarily interfere with the access point devices in the adjacent BSSs. Taking this into consideration, as long as a station device does not set a transmission power higher than necessary for its frames, it can exchange frames within its own BSS without affecting frame exchanges in adjacent BSSs. In PSR operation, a wireless communication device can calculate the maximum transmission power of a PSRT frame that does not affect frame exchanges in adjacent BSSs using the parameter PSR0. The parameter PSR0 is set by the access point device of the OBSS to which the wireless communication device that transmitted the OBSS frame belongs, and is set based on the allowable interference power I0 of the access point device AP. For example, an access point device can measure the received power of frames transmitted from surrounding BSSs during periods when the device itself is not communicating. If this received power is set to RPLx, and the difference between the device's allowable interference power I0 and RPLx is set to PSR0, the impact on frame exchange within the device itself can be reduced even if a wireless communication device in an adjacent BSS transmits a frame at the maximum transmission power calculated based on PSR0.

[0082] By performing PSR operations, the wireless communication device according to this embodiment can transmit a PSRT frame by satisfying certain conditions even when receiving an OBSS frame, thereby resolving the exposed terminal problem and avoiding a decrease in the transmission right acquisition rate. In PSR, P0 is controlled by the parameter PSR0. This is based on the premise that in a wireless LAN, each wireless communication device basically transmits at the same transmission power, so that the interference power between them remains constant. On the other hand, as explained above, the wireless communication device according to this embodiment can transmit OFDM signals with different RU configurations, namely, rRU and dRU. As already explained, even if the rRU and dRU occupy the same bandwidth, the maximum transmission power actually set for the OFDM signal may differ. This suggests that if a PSRT frame is transmitted by a dRU at P0 calculated assuming an rRU, there is a possibility that interference exceeding the allowable interference power I0 may be caused to an OBSS access point device.

[0083] Therefore, the wireless communication device according to this embodiment controls PSR operation based on the configuration of the RU set in the OFDM signal. The wireless communication device according to this embodiment changes the calculation method of P0 based on the configuration of the RU set in the PSRT frame. For example, when the wireless communication device transmits a PSRT frame using an rRU, P0 < PSR0 - RPL0 is the conditional expression for transmitting the PSRT frame, whereas when the wireless communication device transmits a PSRT frame using a dRU, P0 < PSR0 - RPL0 - X can be the conditional expression for transmitting the PSRT frame. Here, X is expressed as a real number, and can be, for example, log10(1 MHz / (T1 x B1)) using the number of tones T1 set per 1 MHz in the dRU and the occupied bandwidth B1 per tone. Furthermore, when the bandwidth occupied by the tones allocated per 1 MHz in the dRU is B2, X can also be log10(1 MHz / (T1 x B1)). Here, log10 represents a function that returns a logarithm with base 10. In other words, when a wireless communication device transmits a PSRT frame using a dRU, the settable maximum transmission power is larger than when transmitting using an rRU, and therefore, there is a possibility that the interference power will be greater than the interference power expected by the access point device that manages the BSS to which the wireless communication device that transmitted the OBSS frame belongs. Therefore, in the wireless communication device according to this embodiment, when transmitting a PSRT frame using a dRU, X can be a real number greater than or equal to 0 in order to set a lower maximum transmission power for the PSRT frame than when transmitting a PSRT frame using an rRU.

[0084] Furthermore, the wireless communication device according to this embodiment can set the value of X based on the period in which the tones set in the RU to which the received PPDU is assigned are allocated. For example, the wireless communication device according to this embodiment can obtain the number indicating the RU to which the received PPDU is assigned and the period in which the tones set in the RU indicated by the number, thereby obtaining the bandwidth occupied by the tones allocated per 1 MHz, and can calculate the value of X using the method described above.

[0085] Furthermore, when a dRU is set in a received PPDU and information indicating the tone allocation period is known, the wireless communication device according to this embodiment can also set the value of X based on information relating the allocation period to the value of X (for example, a table indicating the correspondence between the allocation period and the value of X, or a mathematical formula using the allocation period as a variable).

[0086] The value of X can also be set by the RU configuration of the OBSS frame. The RU configuration indicates rRU or dRU. When the RU configuration indicates dRU, the frame may be transmitted using dRU, or a mixture of rRU and dRU (hybrid) may be transmitted. When the RU configuration is rRU, it is also referred to as an rRU configuration, and when the RU configuration is dRU, it is also referred to as a dRU configuration. When the OBSS frame is a dRU frame and the PSRT frame is transmitted using rRU, the wireless communication device according to this embodiment can set X to log10 ((T1 × B1) / 1 MHz) using the number of tones T10 set per 1 MHz and the occupied bandwidth B1 per tone in the dRU of the OBSS frame. When rRU and dRU are mixed in the dRU configuration, a correction value may be added to X. When a dRU is set in an OBSS frame, the OBSS frame is likely to be received with higher reception power than an OBSS frame with an rRU set (RPL0 is likely to be larger). Therefore, P0 that satisfies P0 < PSR0 - RPL0 will also be a small value. On the other hand, if a PSRT frame is transmitted with an rRU, it is considered that there is a smaller possibility of affecting wireless communication devices in adjacent BSSs than when a PSR frame is transmitted with a dRU. Therefore, in the wireless communication device according to this embodiment, when a dRU is set in the OBSS frame, X can be a negative real number less than 0.

[0087] Furthermore, the wireless communication device according to this embodiment controls the PSR operation based on the RU set in the OBSS frame. When the OBSS frame and the PSRT frame are set to the same RU configuration, the wireless communication device according to this embodiment can transmit the PSRT frame based on the PSR operation. Furthermore, the wireless communication device according to this embodiment can include a condition that a dRU is not set in the OBSS frame as a condition that must be satisfied when performing the PSR operation. In other words, the wireless communication device according to this embodiment can include a condition that an rRU is set in the OBSS frame as a condition that must be satisfied when performing the PSR operation.

[0088] Furthermore, the wireless communication device according to this embodiment can change the interpretation of the PSR0 value acquired from the OBSS frame depending on the RU configuration set in the PSRT frame. The wireless communication device acquires the PSR0 value by reading a numerical value written in a predetermined field included in the PHY header or MAC header of the OBSS frame. At this time, the wireless communication device can share with other wireless communication devices a rule for calculating PSR0 from the numerical value written in the predetermined field. For example, the wireless communication device can share with other wireless communication devices a table that associates the numerical value (or index) written in the predetermined field with the PSR0 value. The wireless communication device according to this embodiment can share with other wireless communication devices two tables: a first table that is referenced when the RU set in the PPDU (frame) is a dRU, and a second table that is referenced when the RU set in the PPDU (frame) is an rRU. For example, the wireless communication device according to this embodiment can refer to the first table when the RU configuration set in the PSRT frame is a dRU, and can refer to the second table when the rRU configuration is set in the PSRT frame. In this case, the value of PSR0 read by the wireless communication device according to this embodiment from the first table using the numerical value entered in the predetermined field is smaller than the value of PSR0 read from the second table using the same numerical value. Furthermore, the wireless communication device according to this embodiment can share with other wireless communication devices the table referenced when the RU set in the PPDU is an rRU, and can acquire PSR0 by adding an offset (e.g., subtracting 3 dBm) to the value of PSR0 read by reference to the table when the RU set in the PPDU is a dRU.

[0089] FIG. 10 is a diagram showing an example of a table indicating PSR0 in this embodiment. This corresponds to an example of the first table in the previous description. FIG. 11 is a diagram showing an example of a table indicating PSR0 in this embodiment. This corresponds to an example of the second table in the previous description. Both illustrate the case where the numerical value written in a predetermined field included in the PHY header or the like is 4 bits. As shown in FIGS. 10 and 11, the table indicating PSR0 lists the value of PSR0 (denoted as PSR in the figures) and can also list other information. For example, in the examples of FIGS. 10 and 11, the information indicated by "0" is "PSR_DISALLOW," which means that transmission of a PSRT PPDU is not permitted.

[0090] In addition, the wireless communication device of this embodiment can refer to the second table if the RU set in the received PPDU is a dRU, and can refer to the first table if the RU set in the received PPDU is an rRU.

[0091] The wireless communication device according to the present embodiment can also obtain the value of PSR0 from a trigger frame that triggers the OBSS frame. The method of associating the numerical value written in the predetermined field with PSR0 is not limited to a table, and can also be, for example, a mathematical expression.

[0092] The wireless communication device according to this embodiment can also acquire the value of X from the OBSS frame and the trigger frame that triggers the OBSS frame. In this case, similar to the PSR0 described above, the wireless communication device according to this embodiment can share in advance with other wireless communication devices a table that associates X with a numerical value written in a predetermined field provided in the PHY header or MAC header of the OBSS frame, but the wireless communication device according to this embodiment can share multiple tables with other wireless communication devices as tables associated with X, based on the configuration of the RU set in the OBSS frame or PSRT frame.

[0093] According to the method described above, the wireless communication device according to this embodiment can efficiently solve the exposed terminal problem even in an environment where frames in which dRUs are set and frames in which rRUs are set coexist, thereby contributing to improving frequency utilization efficiency. [2. Common to all embodiments]

[0094] The communication device according to the present invention can communicate in a frequency band (frequency spectrum) that does not require permission to use from a country or region, which is called an unlicensed band, but the usable frequency band is not limited to this. The communication device according to the present invention can also be effective in, for example, a frequency band called a white band (for example, a frequency band allocated for television broadcasting but unused in some regions) that is not actually used despite permission to use it for a specific service from a country or region for the purpose of preventing interference between frequencies, or in a shared spectrum (shared frequency band) that is expected to be shared by multiple operators.

[0095] The program running on the wireless communication device according to the present invention is a program that controls the CPU and other components (programs that cause a computer to function) to implement the functions of the above-described embodiments of the present invention. Information handled by these devices is temporarily stored in RAM during processing, then stored in various ROMs or HDDs, and read, modified, and written by the CPU as needed. Recording media for storing the program may include semiconductor media (e.g., ROM, non-volatile memory cards, etc.), optical recording media (e.g., DVDs, MOs, MDs, CDs, BDs, etc.), and magnetic recording media (e.g., magnetic tapes, flexible disks, etc.). Executing a loaded program not only implements the functions of the above-described embodiments, but may also implement the functions of the present invention by processing in cooperation with an operating system or other application programs based on instructions from the program.

[0096] Furthermore, when distributing the program on the market, the program can be stored and distributed on a portable recording medium or transferred to a server computer connected via a network such as the Internet. In this case, the storage device of the server computer also falls within the scope of the present invention. Furthermore, part or all of the communication device in the above-described embodiments may be realized as an LSI, which is typically an integrated circuit. Each functional block of the communication device may be individually formed into a chip, or part or all of the functional blocks may be integrated into a chip. When each functional block is formed into an integrated circuit, an integrated circuit control unit for controlling them is added. It goes without saying that the present invention also includes cases where programs and setting information are downloaded from a server computer to implement at least part of the functions of the above-described embodiments.

[0097] Furthermore, the method of integration is not limited to LSI, but may be realized by a dedicated circuit or a general-purpose processor. Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology, it may also be possible to use an integrated circuit based on that technology.

[0098] It should be noted that the present invention is not limited to the above-described embodiments. The wireless communication device of the present invention is not limited to application to mobile station devices, but can of course be applied to stationary or non-mobile electronic devices installed indoors or outdoors, such as AV equipment, kitchen equipment, cleaning / washing appliances, air conditioning equipment, office equipment, vending machines, and other household appliances.

[0099] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and designs that do not deviate from the gist of the present invention are also included in the scope of the claims.

[0100] The present invention is suitable for use in a wireless communication device and a communication method.

[0101] 3001 NDP Announcement frame 3002 NDP frame 3003 Compressed Beamforming / CQI frame 4001-1, 4001-2 Wireless communication device (access point device) 4002-1 to 4002-6 Wireless communication device (station device) 4003-1, 4003-2 Wireless communication system 5001 Wireless control unit 5002 Timer unit 5003 Wireless communication unit 5003a Physical layer frame generation unit 5003b Wireless transmission unit 5003c Wireless reception unit 5003d Received power measurement unit 5003e Channel estimation unit 5003f Signal demodulation unit 5004 Antenna unit 6001 Wireless control unit 10001 MLD access point device 10001-1, 10001-2, 10001-N Sub-access point device 10002 MLD station equipment 10002-1, 10002-2, 10002-N Substation equipment 10011, 10012 Multi-link control unit

Claims

1. A wireless communication device comprising: a receiver that receives an Inter BSS (Basic Service Set) PPDU (PHY Protocol Data Unit); a transmitter that transmits a PSRT (Parameterized Spatial Reuse Transmission) PPDU; and a controller that has the capability of configuring both a dRU (Distributed Resource Unit) configuration consisting of multiple subcarriers spread across a predetermined bandwidth, wherein when the dRU configuration is configured in the PSRT PPDU, the maximum transmission power set in the PSRT PPDU is set based on the received power of the Inter BSS PPDU, a first parameter acquired from the Inter BSS PPDU, and the number of first subcarriers per 1 MHz, and the first subcarriers are the subcarriers that make up the PSRT PPDU.

2. The wireless communication device according to claim 1, wherein the control unit further has the ability to configure an rRU (regular resource unit) configuration consisting of multiple subcarriers arranged adjacently, the first parameter obtained from the Inter BSS PPDU is obtained from a numerical value written in a predetermined field provided in the Inter BSS PPDU, the numerical value written in the predetermined field and the first parameter are associated with a first table and a second table, and the first table is referenced when setting the dRU configuration in the PSRT PPDU, and the second table is referenced when setting the rRU configuration in the PSRT PPDU.

3. The wireless communication device according to claim 1, wherein the control unit is further capable of configuring an rRU (regular resource unit) configuration consisting of multiple adjacently arranged subcarriers, and when the dRU configuration is set in the Inter BSS PPDU, sets the dRU configuration in the PSRT frame, and when the rRU configuration is set in the Inter BSS PPDU, sets the rRU configuration in the PSRT PPDU.

4. A communication method for a wireless communication device, comprising the steps of: receiving an Inter BSS (Basic Service Set) PPDU (PHY Protocol Data Unit); transmitting a PSRT (Parameterized Spatial Reuse Transmission) PPDU; and configuring both a dRU (Distributed Resource Unit) configuration consisting of a plurality of subcarriers spread across a predetermined bandwidth, wherein when the dRU configuration is configured in the PSRT PPDU, the maximum transmission power configured in the PSRT PPDU is set based on the received power of the Inter BSS PPDU, a first parameter acquired from the Inter BSS PPDU, and the number of first subcarriers per 1 MHz, and the first subcarriers are the subcarriers that configure the PSRT PPDU.

Images