Wireless communication apparatus and communication method

Abstract

To provide a radio communication device which avoids an exposed terminal problem under an environment where different RU configurations are mixed while maintaining backward compatibility.SOLUTION: A wireless communication device comprising: a reception unit configured to receive an OBSS frame; a transmission unit configured to transmit a PSRT frame; and a control unit capable of configuring both an rRU configuration composed of a plurality of tones arranged adjacently and a dRU configuration composed of a plurality of tones in which at least one tone is arranged away from another tone by more than a subcarrier spacing, when the dRU configuration is set in the PSRT frame, the maximum transmission power set in the PSRT frame is set based on the reception power of the OBSS frame, the first parameter acquired from the OBSS frame, and the number of tones per 1MHz occupied by the tones included in the OFDM signal constituting the PSRT frame.SELECTED DRAWING: Figure 9

Description

[Technical Field]

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

[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 (Local Area Network) communications and more efficient frequency utilization. Wireless LANs enable wireless communications 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 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 with densely packed wireless LAN devices.

[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. (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 connection (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. From the perspective 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 of the links constituting a multi-link. MLO allows wireless communication devices to simultaneously maintain multiple link connections using different wireless resources and communication-related settings. A wireless communication device can not only send and receive frames using multiple links simultaneously, but also switch the link connections for sending and receiving frames, i.e., change the frequency band, without performing a reconnection operation. 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, discussions are underway on a distributed resource unit (dRU), which discretely allocates subcarriers (tones) instead of continuously allocated subcarriers (as previously described) in order to expand the communication range (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 continuously allocated. In other words, the introduction of a dRU improves the communication range of wireless LAN devices. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] IEEE 802.11-19 / 0773-08-00be, Nov.2019 [Non-patent document 2] IEEE 802.11-24 / 0882r2, May 2024 Summary of the Invention [Problem to be solved by the invention]

[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 with many wireless communication devices, the exposed terminal problem reduces the rate of obtaining communication opportunities, but the signal transmitted by dRU has a longer propagation distance than the signal transmitted by rRU, which exacerbates the exposed terminal problem. [Means for solving the 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 embodiment of the present invention comprises a receiving unit that receives an OBSS (Overlap Basic Service Set) frame, a transmitting unit that transmits a PSRT (Parameterized Spatial Reuse Transmission) frame, and a control unit that is capable of configuring both an rRU (regular Resource Unit) configuration consisting of a plurality of adjacently arranged tones and a dRU (distributed Resource Unit) configuration consisting of a plurality of tones, at least one of which is arranged farther away from the other tones than the subcarrier spacing, and when the dRU configuration is set in the PSRT frame, the maximum transmission power set in the PSRT frame is set based on the received power of the OBSS frame, a first parameter obtained from the OBSS frame, and the number of tones per 1 MHz occupied by the tones of the OFDM signal that constitutes the PSRT frame.

[0010] (2) Furthermore, a wireless communication device according to one embodiment of the present invention is described in (1) above, wherein the first parameter obtained from the OBSS frame is obtained from a numerical value written in a predetermined field provided in the OBSS frame, 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 frame, the first table is referenced, and when setting the rRU configuration in the PSRT frame, the second table is referenced.

[0011] (2) Furthermore, a wireless communication device according to one embodiment of the present invention is described in (1) above, and when the dRU configuration is set in the OBSS frame, sets the dRU configuration in the PSRT frame, and when the rRU configuration is set in the OBSS frame, sets the rRU configuration in the PSRT frame.

[0012] (3) Also, a communication method according to one embodiment of the present invention is a communication method for a wireless communication device, comprising the steps of receiving an OBSS (Overlap Basic Service Set) frame, transmitting a PSRT (Parameterized Spatial Reuse Transmission) frame, and configuring both an rRU (regular Resource Unit) configuration consisting of a plurality of adjacently arranged tones and a dRU (distributed Resource Unit) configuration consisting of a plurality of tones, at least one of which is arranged farther away from the other tones than the subcarrier spacing, and when the dRU configuration is set in the PSRT frame, the maximum transmission power set in the PSRT frame is set based on the received power of the OBSS frame, a first parameter obtained from the OBSS frame, and the number of tones per 1 MHz occupied by the tones of the OFDM signal constituting the PSRT frame. [Effects of the Invention]

[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 mitigated and the rate of obtaining communication opportunities is improved, thereby contributing to improved frequency utilization efficiency. [Brief explanation of the drawings]

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

[0015] The wireless communication system in this embodiment includes an access point device (AP, also referred to as a base station device) and multiple station devices (STA, also referred to as terminal devices). The communication system and network configured with the access point device and the station devices are called 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, one 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 that forms 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 forms a group in place of an access point device. 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. The frames 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 consists of a Physical layer header (PHY header) containing information for signal processing at the Physical layer, and a Physical Service Data Unit (PSDU, PHY layer frame), which is the data unit processed at the Physical layer. A PSDU can be configured to include an Aggregated MPDU (A-MPDU), which aggregates multiple MAC Protocol Data Units (MPDU, MAC layer frames), which are the units of retransmission in the wireless section.

[0019] 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. Depending on the corresponding standard, STFs are classified as Legacy-STF (L-STF), High Throughput-STF (HT-STF), Very High Throughput-STF (VHT-STF), High Eficiency-STF (HE-STF), and Extremely High Throughput-STF (EHT-STF). Similarly, LTFs and SIGs are classified as 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, assuming technical updates in the same standard, a Universal SIGNAL (U-SIG) field containing additional control information can be included.

[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, 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 the data unit processed at the MAC layer, and a Frame Check Sequence (FCS), which checks whether the frame is error-free (Figure 1). Multiple MSDUs can also be aggregated into an Aggregated MSDU (A-MSDU).

[0023] Frame types at the MAC layer are broadly classified into three: management frames, which manage the connection status between devices; control frames, which manage the communication status between devices; and data frames, which contain the actual transmitted data. Each of these 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 frame control field in the MAC header.

[0024] A beacon frame includes a field indicating the period (beacon interval) at which beacons are 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, which includes a status code indicating whether the station device has been authenticated. By reading the status code included in the authentication response frame, the station device can determine whether its own authentication request has been approved by the access point device. Note that 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 initiate a connection procedure. Upon receiving the connection request frame, the access point device determines whether to permit the station device to connect and transmits a connection response frame to notify the result. The connection response frame contains a status code indicating whether the connection process is successful, as well as an association ID (AID) for identifying the station device. The access point device can manage multiple station devices by assigning different AIDs to each station device for which it has issued a connection permission.

[0027] After the connection process is completed, the access point device and station device perform actual data transmission. The IEEE 802.11 system defines the Distributed Coordination Function (DCF), Point Coordination Function (PCF), and their extended Hybrid Coordination Function (HCF) as media access methods. Specific implementation methods for 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 wireless channels around the device before communication. For example, if an access point device or a station device that is about to transmit a frame receives a signal with a received power higher than a predetermined clear channel assessment level (CCA level) on the wireless channel during the carrier sense period performed prior to transmission, the access point device or the station device postpones the transmission of the frame on the wireless channel. Hereinafter, a state in which a signal with a received power equal to or higher than the CCA level is detected on the wireless channel is referred to as a busy state, and a state in which a signal with a received power equal to or higher than the CCA level is not detected is referred to as an idle state. This 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 a carrier sense level (CS level) or a 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) that is 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 the access point device is about to transmit. The IEEE 802.11 system defines several IFSs with different durations, including the short interframe space (SIFS) used for frames assigned the highest priority, the polling interframe space (PIFS: PCF IFS) used for frames with relatively high priority, and the distributed arbitration interframe space (DIFS: DCF IFS) used for frames with low priority. When transmitting data frames using DCF, the access point device uses 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 frame correctly. Therefore, frame collisions are avoided by having each transmitting station wait for a randomly set time before starting transmission. When the access point device determines through carrier sense that the wireless channel is idle, it starts counting down a backoff counter set based on the CW. Only when the backoff counter reaches 0 does it acquire the right to transmit and transmit a frame to the station device. If the access point device determines through carrier sense that the wireless channel is busy 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 Identifier, 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 an Ack frame from the station device. Note that if the station device does not 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 a frame, it determines that the communication has failed and terminates the communication. In this way, 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 transmitting a beacon frame or other notification signal, or when fragmentation is used to divide the transmitted data.

[0033] When a station device determines that a received frame is not addressed to itself, it sets a network allocation vector (NAV) based on the length of the frame contained 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 based on physical CS during the period set in the NAV, so communication control using NAV is also called virtual carrier sense (virtual CS). In addition to being set based on information contained 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 a 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 a CW. The 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 within the BSS (e.g., a data frame including CF-end) is received, the station device can acquire the transmission right only when it receives a signal signaling acquisition of the transmission right for itself (e.g., a data frame including CF-poll) from the PC. 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] A 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 structure 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 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 Data frame. The 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 Data frames.The PPDU considered for the IEEE 802.11be standard is configured to include some or all of the following: 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 conforming to the IEEE 802.11a / g standard can properly receive an L-header in a PPDU conforming to the IEEE 802.11n / ac / ax / be standard. A wireless communication device conforming to the IEEE 802.11a / g standard can receive a PPDU conforming to the IEEE 802.11n / ac / ax / be standard, treating it as a PPDU conforming to the IEEE 802.11a / g standard.

[0038] However, wireless communication devices that comply with the IEEE 802.11a / g standard 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 for inserting duration information into L-SIG as a method for wireless communication devices conforming to the IEEE 802.11a / g standard to appropriately set NAV (or perform reception for a predetermined period of time). Information about the transmission rate in the L-SIG (RATE field, L-RATE field, L-RATE, L_DATARATE, L_DATARATE field) and information about the transmission duration (LENGTH field, L-LENGTH field, L-LENGTH) are used by wireless communication devices 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 successfully 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 while receiving a PPDU, the wireless communication device can receive 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 the 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). In addition, 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 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 sounding to be performed (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] 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, wireless communication device 4001-1 and wireless communication device 4001-2 (access point devices 4001-1, 4001-6) will also be referred to as wireless communication device 4001 (access point device 4001) when described without specifying each individual device, and wireless communication devices 4002-1 to 4002-6 (station devices 4002-1 to 4002-6) will also be referred to as wireless communication device 4002 (station device 4002) when described without specifying each individual device. 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. Also, 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 further 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 radio control unit (radio control step) 5001, a timer unit (timer step) 5002, a radio communication unit (radio communication step) 5003, and an antenna unit 5004. Furthermore, radio communication unit 5003 includes a physical layer frame generation unit (physical layer frame generation step) 5003a, a radio transmission unit (radio transmission step) 5003b, a radio reception unit (radio 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] Timer unit 5002 includes one or more timers and manages the timers related to the sounding process. Details of timer unit 5002 will be described later. Note that, in the example of Fig. 5, timer unit 5002 is shown as being included in wireless control unit 5001, but is not limited to this configuration, and may be configured to be provided outside wireless control unit 5001 and to operate under control from 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 (e.g., 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 a received signal of an 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 result in the received power measuring unit 5003d and the information acquired in the signal demodulation unit 5003f, 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, or the like 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, when the wireless channel state determination information indicates an idle state, the wireless control unit 5001 can countdown the backoff counter, and when the wireless channel state determination information indicates a busy state, the wireless control unit 5001 can stop the countdown. 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, when the wireless channel state determination information indicates an idle state and the backoff counter value is 0, the wireless control unit 5001 can notify the wireless communication unit 5003 of transmission decision information. Furthermore, when the wireless resource state determination information indicates an idle state, the wireless control unit 5001 can notify the wireless communication unit 5003 of transmission decision information.

[0056] FIG. 6 is a diagram showing 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 in FIG. 6 is basically configured similarly to the station device 4002 in 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 in FIG. 5 will be described using the same reference numerals.

[0057] The wireless control unit 6001 performs information processing for 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.

[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 radio waves 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 received signal of the LTF 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, when the wireless channel state determination information indicates an idle state, the wireless control unit 6001 can countdown the backoff counter, and when the wireless channel state determination information indicates a busy state, the wireless control unit 6001 can stop the countdown. 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, when the wireless channel state determination information indicates an idle state and the backoff counter value is 0, the wireless control unit 6001 can notify the wireless communication unit 5003 of transmission decision information. Furthermore, when the wireless resource state determination information indicates an idle state, the wireless control unit 6001 can notify the wireless communication unit 5003 of transmission decision information.

[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 is referred to as an MLD access point device, and a station device that supports MLO is referred to as an MLD station device. Furthermore, MLD access point devices and MLD station devices are collectively referred to as MLD wireless communication devices. In this embodiment, wireless communication devices 4001-1, 4001-2, 4002A, and 4002B described above are described as MLD wireless communication devices, but in actual operation, not all wireless communication devices in a wireless communication system necessarily support MLO.

[0065] The MLD access point device 10001 and MLD station device 10002 will be described using Figure 7. An 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 called a physical layer link) that constitutes a multilink. Each sub-wireless communication device may be compatible with all frequency bands (and frequency channels) supported by the MLD wireless communication device, or each may be compatible with one of the frequency bands (or frequency channels). Figure 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 sub-access point device 10001-N. 8 shows an example in which the MLD station device 10002 is similarly configured with two sub-wireless communication devices, in this case two substation devices 10002-1 and 10002-2, and a multilink control unit 10012, but the number of substation devices may be any number equal to or greater than 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 a portion of the circuitry 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 more sub-wireless communication devices (sub-access point devices, substation devices) it may have. In other words, for each MLD wireless communication device existing in one 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] Substation apparatus 10002-1 associates with sub-access point apparatus 10001-1 and establishes wireless link 10003-1 (first wireless link), while substation apparatus 10002-2 associates with sub-access point apparatus 10001-2 and establishes wireless link 10003-2 (second wireless link).

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

[0070] 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 explanation, 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 the present invention is not limited to this and can be similarly applied to cases in which the number of wireless links is three or more. Also, 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 2.4 GHz, 5 GHz, 6 GHz, and 60 GHz, and these 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 configured by a wireless communication device in this embodiment. As described above, the wireless communication device in this embodiment can use an orthogonal frequency division multiplexing (OFDM) signal as a modulated signal that configures a transmission frame. Furthermore, the wireless communication device (mainly an access point device) in this embodiment can implement orthogonal frequency division multiple access (OFDMA), which divides a predetermined number of subcarriers (tones) that configure 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 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). A 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 consecutive 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 allocated 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 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 allocated 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 allocated adjacent to each other. For simplicity, the following description will be given assuming that the number of tones allocated per station device is the same for a dRU and an rRU.

[0074] In the rRU method shown in Fig. 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. Note that the access point device can allocate one RU to one station device, or the access point device 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 RU 901-1 and RU 901-2, and RU 901-1 and RU 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 apparatus according to this embodiment, the number of available tones is the same when an RU 801 configured as a dRU is assigned and when an RU 901 configured as an rRU is assigned. However, when transmitting an OFDM signal configured with the assigned tones, the maximum transmit power that can be set for the OFDM signal differs. This is because the maximum transmit power that can be set for an OFDM signal in the wireless communication apparatus 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 transmit power per unit frequency in 10 MHz units is specified as 10 dBm for the station apparatus according to this embodiment. In this case, if an RU 801 that is an rRU is assigned to the station apparatus, the RU 801 will set the maximum transmit 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 configured in the station equipment, RU901-1 contains half of all tones transmitted in the lower 10 MHz frequency of the entire communication bandwidth, while RU901-2 contains the other half of all tones transmitted in the higher 10 MHz frequency, so the station equipment can set 10 dBm as the maximum transmission power for each of RU901-1 and RU902-2, and can therefore 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 of specifying the maximum transmission power, but it goes without saying that the wireless communication apparatus 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 configuring a dRU 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 setting a number in the RU and notifying the other wireless communication device of the number. Since different numbers are set for 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 in 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 SR (PSR) operation as the SR operation. A frame transmitted by the wireless communication device based on the PSR operation is called 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 to be set in the PSRT PPDU is P0, the wireless communication device can start transmitting the PSRT PPDU if P0 is smaller than the value obtained by subtracting RPL0 from PSR0. Note that P0 can be defined in dBm. Furthermore, when the bandwidth of the PSRT frame is PPDU_BW, P0 can be defined as a value obtained by subtracting the decibel value of the value obtained by dividing 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 the 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 level 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 a 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 neighboring 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 operation, the wireless communication device according to this embodiment can transmit a PSRT frame by satisfying certain conditions even when receiving an OBSS frame. This solves the exposed terminal problem and prevents a decrease in the transmission right acquisition rate. In PSR, P0 is controlled by the parameter PSR0. This is based on the assumption 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 transmitting a PSRT frame using a dRU at P0 calculated assuming an rRU may cause interference exceeding the allowable interference power I0 to an OBSS access point device.

[0083] Therefore, the wireless communication device according to the present embodiment controls the PSR operation according to the configuration of the RU set in the OFDM signal. The wireless communication device according to the present 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 being able to transmit the PSRT frame. In contrast, when the wireless communication device transmits a PSRT frame using a dRU, P0 < PSR0 - RPL0 - X can be the conditional expression for being able to transmit the PSRT frame. Here, X is expressed as a real number. For example, it can be set to log10(1MHz / (T1×B1)) using the number of tones T1 set per 1MHz and the occupied bandwidth B1 per tone in the dRU. Also, when the bandwidth occupied by the tones arranged per 1MHz in the dRU is set as B2, X can also be set to log10(1MHz / (T1×B1)). Here, log10 represents a function that returns the logarithm with base 10. That is, when the wireless communication device transmits a PSRT frame using a dRU, compared with the case of transmitting using an rRU, the maximum transmit power that can be set is larger. Therefore, there is a possibility of affecting the access point device that manages the BSS to which the wireless communication device that transmitted the OBSS frame belongs, with interference power greater than the interference power assumed by the access point device. Therefore, when the wireless communication device according to the present embodiment transmits a PSRT frame using a dRU, in order to set a smaller maximum transmit power for the PSRT frame than in the case of transmitting a PSRT frame using an rRU, X can be a real number greater than or equal to 0.

[0084] In addition, the wireless communication device according to the present 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 arranged. For example, the wireless communication device according to the present embodiment obtains the number indicating the RU to which the received PPDU is assigned, and obtains the arrangement period of the tones set in the RU indicated by the number, so that the bandwidth occupied by the tones arranged per 1MHz can be obtained. Therefore, the value of X can be calculated by the method described above.

[0085] In addition, when a dRU is set in the received PPDU and information indicating the arrangement period of tones can be grasped, the wireless communication device according to the present embodiment can also set the value of X based on information associating the arrangement period with the value of X (for example, a table showing the correspondence between the arrangement period and the value of X, or a mathematical formula with the arrangement period as a variable).

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

[0087] Furthermore, the wireless communication device according to this embodiment controls 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 PSR operation. Furthermore, the wireless communication device according to this embodiment can include the condition that a dRU is not set in the OBSS frame in the conditions that must be satisfied when performing PSR operation. In other words, the wireless communication device according to this embodiment can include the condition that an rRU is set in the OBSS frame in the conditions that must be satisfied when performing 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 to be 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 in advance 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 reference the first table when the RU configuration to be set in the PSRT frame is a dRU, and can reference the second table when the rRU configuration to be set in the PSRT frame. In this case, the value of PSR0 that the wireless communication device according to this embodiment reads from the first table using the numerical value entered in the predetermined field will be smaller than the value of PSR0 that the wireless communication device according to this embodiment reads 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 that is referenced when the RU set in the PPDU is an rRU, and when the RU set in the PPDU is a dRU, can acquire PSR0 by adding an offset (for example, subtracting 3 dBm) to the value of PSR0 that can be read by reference to the table.

[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 above 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 above description. Both show 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 PSRT PPDUs is not permitted.

[0090] In addition, the wireless communication device of this embodiment can also 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 this embodiment can also obtain the value of PSR0 from the 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 obtain 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. However, 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 of this embodiment can efficiently solve the exposed terminal problem even in an environment where frames with dRUs set and frames with rRUs set are mixed, 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) called an unlicensed band, which does not require permission to use from a country or region, but the usable 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 it for a specific service is granted by a country or region, 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 a CPU and other components (a program that causes a computer to function) so as to realize the functions of the above-described embodiments of the present invention. Information handled by these devices is temporarily stored in RAM during processing, and then stored in various ROMs or HDDs, from which the CPU reads, modifies, and writes the information as needed. Recording media for storing the programs may include semiconductor media (e.g., ROMs, 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 realizes the functions of the above-described embodiments, but may also realize 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 that controls 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 integrated circuit method is not limited to LSI, and may be realized by dedicated circuits or general-purpose processors. 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 equipment, 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. [Industrial Applicability]

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

[0101] 3001 NDP Announcement Frame 3002 NDP Frame 3003 Compressed Beamforming / CQI Frame 4001-1, 4001-2 Wireless communication device (access point device) 4002-1~6 Wireless communication equipment (station equipment) 4003-1, 4003-2 Wireless communication systems 5001 Radio control unit 5002 Timer section 5003 Wireless Communication Department 5003a Physical layer frame generator 5003b Radio transmitter 5003c Wireless receiver 5003d Received power measurement unit 5003e Channel Estimation Unit 5003f signal demodulation unit 5004 Antenna part 6001 Radio control unit 10001 MLD access point device 10001-1, 10001-2, 10001-N sub-access point devices 10002 MLD station equipment 10002-1, 10002-2, 10002-N Substation Equipment 10011, 10012 Multi-link control unit

Claims

1. A wireless communication device, a receiving unit for receiving an OBSS (Overlap Basic Service Set) frame; a transmitter that transmits a parameterized spatial reuse transmission (PSRT) frame; a control unit capable of configuring both an rRU (regular resource unit) configuration consisting of a plurality of adjacently arranged tones and a dRU (distributed resource unit) configuration consisting of a plurality of tones, at least one of which is arranged at a distance greater than the subcarrier spacing from the other tones; When the dRU configuration is set in the PSRT frame, the maximum transmission power set in the PSRT frame is set based on the received power of the OBSS frame, a first parameter obtained from the OBSS frame, and the number of tones per 1 MHz occupied by the tones of the OFDM signal that constitutes the PSRT frame.

2. the first parameter acquired from the OBSS frame is acquired from a numerical value written in a predetermined field included in the OBSS frame; the numerical value written in the predetermined field and the first parameter are associated with a first table and a second table; When setting the dRU configuration in the PSRT frame, refer to the first table; The wireless communication device according to claim 1 , wherein the second table is referenced when the rRU configuration is set in the PSRT frame.

3. When the dRU configuration is set in the OBSS frame, set the dRU configuration in the PSRT frame; The wireless communication device according to claim 1 , wherein when the rRU configuration is set in the OBSS frame, the rRU configuration is set in the PSRT frame.

4. A communication method for a wireless communication device, comprising: receiving an Overlap Basic Service Set (OBSS) frame; transmitting a Parameterized Spatial Reuse Transmission (PSRT) frame; configuring both a regular resource unit (rRU) configuration consisting of a plurality of adjacently arranged tones and a distributed resource unit (dRU) configuration consisting of a plurality of tones, at least one of which is arranged at a distance greater than the subcarrier spacing from another tone; When the dRU configuration is set in the PSRT frame, the maximum transmission power set in the PSRT frame is set based on the reception power of the OBSS frame, a first parameter obtained from the OBSS frame, and the number of tones per 1 MHz occupied by the tones of the OFDM signal that constitutes the PSRT frame.

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