Communication equipment and communication methods

Abstract

Provided is a communication device which performs wireless communication by using multiple links so that the difference between transmission termination times of the respective links is within a prescribed time.　The communication device comprises: a first communication unit which performs communication via a first link; a second communication unit which performs communication via a second link; and a control unit which controls communication operations using the first link and the second link by means of the first communication unit and the second communication unit. The control unit controls the length of a transmission frame in the first link or the second link when the first communication unit starts transmission first via the first link.

Description

Technical Field

[0001] The technology disclosed in this specification (hereinafter referred to as "the present disclosure") relates to a communication device and a communication method for performing wireless communication using a plurality of links.

Background Art

[0002] As a method for coping with high-resolution image data such as 8K and high transmission speed requirements such as XR (a general term for VR, AR, MR, and SR), wireless communication using a plurality of links (Multi-link Operation: MLO) has been studied. The "link" mentioned here is a wireless transmission path capable of transmitting data between two communication devices. When performing MLO, each link is selected from a plurality of mutually independent wireless transmission paths divided, for example, in the frequency domain. Specifically, channels respectively selected from a plurality of channels included in any one of frequency bands such as the 2.4 GHz band, 5 GHz band, 6 GHz band, and 920 MHz band are used.

[0003] A communication device corresponding to MLO is called an MLD (Multi-link Device). An MLD is a logical entity that includes one or more communication terminals (STation: STA) and has only one SAP (Service Access Point) to the upper layer. An MLD in which each included STA is an access point (AP) is called an AP MLD. Also, an MLD that is not an access point, that is, a non-AP STA, is called a non-AP MLD.

[0004] MLDs transmit signals using multiple links, but due to factors such as the proximity of frequencies between links, transmission signals may leak from one link, strongly interfering with received signals on other links and degrading communication quality. A pair of links that has such constraints when simultaneously transmitting and receiving signals between links is called an NSTR (Non-Simultaneous Transmit and Receive) link pair. In contrast, a pair of links that has no constraints when simultaneously transmitting and receiving signals between links, such as when leakage power between links does not affect communication quality, is called an STR (Simultaneous Transmit and Receive) link pair. In this specification, when an AP MLD and a non-AP MLD are communicating using a certain link pair, and that link pair is an STR link pair for the AP MLD but an NSTR link pair for the non-AP MLD, the AP MLD is defined as an STR AP MLD, and the non-AP MLD is defined as a non-STR non-AP MLD.

[0005] For example, when an AP MLD sends a DL (Downlink) PPDU (PLCP (Physical Layer Convergence Protocol) Protocol Data Unit) to an NSTR non-AP MLD on multiple links, if the NSTR non-AP MLD attempts to send an ACK on a link where transmission has already finished, the transmitted signal may leak and interfere with the received signal on other links where transmission has not yet finished, potentially degrading communication quality.

[0006] Therefore, Non-Patent Document 1 states that when an AP MLD sends a DL PPDU to an NSTR non-AP MLD via multiple links, if the DL PPDU is a PPDU that requests an immediate response from the NSTR non-AP MLD after SIFS (Short Inter Frame Space) has elapsed since the end of transmission, the AP MLD will send the DL PPDU so that the difference in the end times of DL PPDU transmission on each link is within a predetermined range, so that the reception of the DL PPDU and the transmission of the immediate response after SIFS, in which the DL PPDU has been received, do not occur simultaneously in the NSTR non-AP MLD. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] Edward Au,et al.,"Specification Framework for TGbe,"IEEE 802.11-19 / 1262r23,Jan.17,2021 [Non-Patent Document 2] Robert Stacy,et al.,"Proposed TGax draft specification,"IEEE 802.11-16 / 0024r1,March.2,2016 [Overview of the project] [Problems that the invention aims to solve]

[0008] The object of the present invention is to provide a communication device and a communication method that perform wireless communication using multiple links such that the difference in the transmission completion times of each link is within a predetermined range. [Means for solving the problem]

[0009] This disclosure has been made in consideration of the above issues, and its first aspect is: A first communication unit that communicates via the first link, A second communication unit that communicates via the second link, A control unit that controls the communication operation using the first link and the second link by the first communication unit and the second communication unit, It is equipped with, The control unit controls the transmission frame length in the first link or the second link when the first communication unit starts transmitting first on the first link. It is a communication device.

[0010] The control unit controls the transmission frame length in the first link or the second link based on information regarding the transmission data initiated by the first communication unit and information regarding the transmission data to be transmitted by the second communication unit. The information regarding the transmission data includes at least the OFDM symbol length, the number of OFDM symbols, and the transmission start time (including the scheduled transmission start time).

[0011] The control unit controls the transmission frame length so that the difference between the transmission end time on the first link by the first communication unit and the scheduled transmission end time on the second link by the second communication unit is less than a predetermined value, if the difference between the transmission end time and the scheduled transmission end time is less than a predetermined value.

[0012] Furthermore, a second aspect of this disclosure is a communication method in which a communication device communicates using a first link and a second link, The first step is to start sending using the aforementioned link, A step of controlling the transmission frame length in the first link or the second link so that the difference between the transmission end time in the first link and the scheduled transmission end time in the second link is less than a predetermined value, It is a communication method that has [a certain feature]. [Effects of the Invention]

[0013] According to the present disclosure, when performing wireless communication using a plurality of links, a communication apparatus and a communication method can be provided that align the transmission end times of each link by adjusting the length of a transmission frame on a specific link.

[0014] Note that the effects described in this specification are merely examples, and the effects brought about by the present disclosure are not limited thereto. Further, the present disclosure may also exhibit additional effects other than the above effects.

[0015] Still other objects, features, and advantages of the present disclosure will become apparent from more detailed descriptions based on the embodiments described later and the accompanying drawings.

Brief Description of the Drawings

[0016] [Figure 1] FIG. 1 is a diagram showing a configuration example of a communication system. [Figure 2] FIG. 2 is a diagram showing a functional configuration example of the communication apparatus 200. [Figure 3] FIG. 3 is a flowchart showing a processing procedure for performing MLO so that the transmission end times on a plurality of links are aligned. [Figure 4] FIG. 4 is a diagram showing a configuration example of a frame including Capability information. [Figure 5] FIG. 5 is a diagram showing a communication sequence in which the AP MLD adjusts the PPDU length on a specific link to align the transmission end times between links. [Figure 6] FIG. 6 is a diagram showing another communication sequence in which the AP MLD adjusts the PPDU length on a specific link to align the transmission end times between links. [Figure 7] FIG. 7 is a diagram showing OFDM symbols used in a PPDU format before IEEE802.11ax and OFDM symbols used in a PPDU format after IEEE802.11ax.

Embodiments for Carrying Out the Invention

[0017] The present disclosure will be described below in the following order, with reference to the drawings.

[0018] A. System Configuration B. Configuration of communication equipment C. Transmission operation D. Example of a communication sequence E. Effects

[0019] A. System Configuration Figure 1 schematically shows an example of the configuration of a communication system to which this disclosure applies. The illustrated communication system consists of an AP MLD and a Non-AP MLD, and MLO is implemented. The AP MLD is a communication device equivalent to a base station that supports MLO. The Non-AP MLD is a communication device equivalent to a terminal that supports MLO. The Non-AP MLD is connected to the AP MLD by multiple links. In Figure 1, the solid and dashed lines drawn between the AP MLD and the Non-AP MLD indicate different links (link1 and link2) that wirelessly connect the AP MLD and the Non-AP MLD, respectively.

[0020] The links used in the communication system shown in Figure 1 are wireless transmission paths that enable data transmission between two communication devices. Each link is selected from, for example, multiple independent wireless transmission paths (channels) divided by frequency domain. A single link may consist of two channels selected from the same frequency band, or two channels selected from different frequency bands. Furthermore, the number of links used between the AP MLD and Non-AP MLD is not limited to two; communication may be conducted using three or more links.

[0021] In this embodiment, it is also assumed that data frames in different formats with different OFDM (Orthogonal Frequency Division Multiplexing) symbol lengths may be transmitted for each link. For example, it is assumed that one link transmits a non-HE PPDU (hereinafter also referred to as "non-HE (High-Efficiency) PPDU") based on a format prior to IEEE 802.11ax, while the other link transmits an HE / EHT PPDU (HE PPDU or EHT (Extreme High Throughput) PPDU, hereinafter referred to as "HE / EHT PPDU" in this specification) based on a format later than IEEE 802.11ax (see Non-Patent Document 2).

[0022] B. Configuration of communication equipment Figure 2 shows an example of the internal configuration of the communication device 200. The communication device 200 is an MLO-compatible communication device and is intended to operate as an AP MLD or Non-AP MLD in the communication system shown in Figure 1. The communication device 200 mainly consists of a communication unit 210, a control unit 220, a storage unit 230, and an antenna 240. The communication unit 210 also includes a communication control unit 211, a communication storage unit 212, a data processing unit consisting of a common data processing unit 213 and an individual data processing unit 214, a signal processing unit 215, a wireless interface (IF) unit 216, and an amplification unit 217.

[0023] An individual data processing unit 214, a signal processing unit 215, a wireless interface (IF) unit 216, an amplification unit 217, and an antenna 240 are provided for each link. The communication device 200 is intended to perform MLO using two links, a first link and a second link. For example, an individual data processing unit 214-1, a signal processing unit 215-1, a wireless interface unit 216-1, an amplification unit 217-1, and an antenna 240-1 are designated as an individual communication set for transmission and reception processing on the first link, and an individual data processing unit 214-2, a signal processing unit 215-2, a wireless interface unit 216-2, an amplification unit 217-2, and an antenna 240-2 are designated as another individual communication set for transmission and reception processing on the second link. For example, one individual communication set transmits and receives non-HE PPDU based on an IEEE 802.11ax or earlier format on the first link, while the other individual communication set transmits and receives HE / EHT PPDU based on an IEEE 802.11ax or later format on the second link.

[0024] The communication control unit 211 controls the operation of each part within the communication unit 210 and the transmission of information between each part. The communication control unit 211 also controls the transfer of control information and management information to be notified to other communication devices to the data processing units (common data processing unit 213, individual data processing unit 214-1, and individual data processing unit 214-2).

[0025] In this disclosure, the communication control unit 211 includes a first individual control unit and a second individual control unit that control each individual communication set, a common data processing unit, and a common control unit that performs control common to each individual communication set. Each individual control unit transmits control information (such as OFDM symbol length) related to the transmission data unit to other individual control units. This information may be transmitted via the common control unit.

[0026] The communication storage unit 212 stores information used by the communication control unit 211. The communication storage unit 212 also stores data transmitted by the communication device 200 and data received by the communication device 200.

[0027] When transmitting, the common data processing unit 213 performs sequence management of the data held in the communication storage unit 212 and the control and management information received from the communication control unit 211, generates data units through encryption and other processes, and allocates them to the individual data processing units 214-1 and 214-2. When receiving, the common data processing unit 213 performs decryption and reordering of the data units.

[0028] Individual data processing units 214-1 and 214-2 perform, during transmission, channel access operations based on carrier sense on their respective links, the addition of MAC (Media Access Control) headers and error detection codes to the data to be transmitted, and the concatenation of multiple data units. Furthermore, during reception, individual data processing units 214-1 and 214-2 perform, respectively, the deconcatenation of MAC headers of received data units on their respective links, analysis, error detection, and retransmission request operations.

[0029] Furthermore, the operation of the common data processing unit 213 and the individual data processing units 214-1 and 214-2 is not limited to the above. For example, the common data processing unit 213 may also perform the operations of the individual data processing units 214-1 and 214-2, or one of the individual data processing units 214-1 and 214-2 may perform at least a part of the operation of the common data processing unit 213, or one of the individual data processing units 214-1 and 214-2 may perform the operation of the other.

[0030] Signal processing units 215-1 and 215-1-2 perform encoding, interleaving, and modulation of data units during transmission, add a physical header, and generate a symbol stream. During reception, signal processing units 215-1 and 215-2 analyze the physical header, demodulate, deinterleave, and decode the symbol stream, and generate data units. Furthermore, signal processing units 215-1 and 215-2 perform complex channel characteristic estimation and spatial separation processing as needed.

[0031] During transmission, wireless interface units 216-1 and 216-2 perform digital-to-analog signal conversion, filtering, upconversion, and phase control on the symbol stream to generate a transmission signal. During reception, wireless interface units 216-1 and 216-2 perform downconversion, filtering, and analog-to-digital signal conversion on the received signal to generate a symbol stream.

[0032] Amplifiers 217-1 and 217-2 amplify the signals input from wireless interface units 216-1 and 216-2 during transmission. Amplifiers 217-1 and 217-2 also amplify the signals input from antennas 240-1 and 240-2 during reception. Parts of amplifiers 217-1 and 217-2 may be components outside the communication unit 210. Furthermore, parts of amplifiers 217-1 and 217-2 may be incorporated into wireless interface units 216-1 and 216-2.

[0033] The control unit 220 controls the communication unit 210 and the communication control unit 211. The control unit 220 may also perform some of the operations of the communication control unit 211. Furthermore, the communication control unit 211 and the control unit 220 may be configured as a single block.

[0034] The storage unit 230 holds information used by the communication unit 210 and the control unit 220. The storage unit 230 may also perform some of the operations of the communication storage unit 212. Furthermore, the storage unit 230 and the communication storage unit 212 may be configured as a single block.

[0035] The individual data processing unit 214-1, signal processing unit 215-1, wireless interface unit 216-1, amplification unit 217-1, and antenna 240-1 are configured as one individual communication set to perform wireless communication on the first link. Additionally, the individual data processing unit 214-2, signal processing unit 215-2, wireless interface unit 216-2, amplification unit 217-2, and antenna 240-2 are configured as another individual communication set to perform wireless communication on the second link. Although only two individual communication sets are shown in Figure 2, the communication device 200 can consist of three or more individual communication sets, with each set performing wireless communication on its respective link. Furthermore, a storage unit 230 or a communication storage unit 212 may be included in each individual communication set.

[0036] A link is a wireless transmission path that enables data transmission between two communication devices, and each link is selected from, for example, multiple independent wireless transmission paths (channels) divided in the frequency domain. The links used by each of the above individual communication sets may be two channels selected from the same frequency band, or two channels selected from different frequency bands. Alternatively, an individual data processing unit 214 and a signal processing unit 215 may be considered as one set, and two or more sets may be configured to connect to a single common wireless interface unit 216.

[0037] The wireless interface unit 216, the amplification unit 217, and the antenna 240 are considered as one set, and two or more sets may constitute components of the communication device 200.

[0038] The communication unit 210 can also be composed of one or more LSIs (Large Scale Integrations).

[0039] The common data processing unit 213 is also called the Upper MAC or Higher MAC, and the individual data processing unit 214 is also called the Lower MAC. The combination of the individual data processing unit 214 and the signal processing unit 215 is also called the AP entity or Non-AP entity. Furthermore, the communication control unit 211 is also called the MLD management entity.

[0040] Furthermore, in this specification, the functional blocks (or individual communication sets) from the antenna 240 to the individual data processing unit 214 and the individual control unit are collectively referred to as STA.

[0041] In this embodiment, it is also assumed that the communication device 200 transmits data frames in a format with different OFDM symbol lengths for each link. For example, on the first link, a non-HE PPDU based on a format prior to IEEE 802.11ax is transmitted, and on the second link, an HE / EHT PPDU based on a format later than IEEE 802.11ax is transmitted.

[0042] C. Transmission operation For example, when an AP MLD sends a DL PPDU (Physical Layer Protocol Data Unit) to an NSTR non-AP MLD via multiple links, if the NSTR non-AP MLD attempts to send an ACK (immediate response) on a link where transmission has already finished, the transmitted signal may leak and interfere with the received signal on other links where transmission has not yet finished, potentially degrading communication quality.

[0043] Therefore, Non-Patent Document 1 stipulates that when an AP MLD transmits a DL PPDU to an NSTR non-AP MLD via multiple links, if the DL PPDU is a PPDU that requests an immediate response from the NSTR non-AP MLD after SIFS (Short Inter Frame Space) has elapsed since the end of transmission, the difference in the end time of transmission of the DL PPDU should be within 8 microseconds (however, if the frame requests the return of the PPDU to the destination and includes a frame that requests carrier sense before the destination transmits the PPDU (specifically, if the DL PPDU is a trigger frame and the CS Required subfield in the trigger frame is set to 1, and carrier sense is requested before the transmission of the PPDU induced by the trigger), the difference should be within 4 microseconds).

[0044] However, the OFDM symbol length differs between PPDUs transmitted using IEEE 802.11ax or earlier formats and those transmitted using IEEE 802.11ax or later formats. Figure 7 shows the OFDM symbols used in PPDU formats prior to IEEE 802.11ax and those used in PPDU formats later than IEEE 802.11ax. Specifically, non-HE PPDUs have 3.2 microseconds of OFDM symbols with a 0.4 microsecond or 0.8 microsecond GI (Guard Interval) inserted, resulting in a symbol length of either 3.6 microseconds or 4.0 microseconds (see Figures 7(A) and 7(B)). In contrast, in the data portion of HE / EHT PPDU, a GI of 0.8 microseconds, 1.6 microseconds, or 3.2 microseconds is inserted for each 12.8 microsecond OFDM symbol, resulting in a total length of 13.6 microseconds, 14.4 microseconds, or 16.0 microseconds per symbol (see Figures 7(C) to (E)). Therefore, when transmitting a non-HE PPDU based on an IEEE 802.11ax or earlier format on one link and simultaneously transmitting an HE / EHT PPDU based on an IEEE 802.11ax or later format on the other link, and attempting to synchronize the transmission end times, a difference of 8 microseconds (or 4 microseconds) or more may occur due to the difference in the number of symbols. For example, even if the number of MPDUs aggregated or padding is performed in a non-HE PPDU based on a format prior to IEEE 802.11ax, it is conceivable that the transmission completion time may end up being 8 microseconds (or 4 microseconds) or more earlier than that of an HE / EHT PPDU based on a format later than IEEE 802.11ax.

[0045] Therefore, in this disclosure, for example, in a communication system implementing MLO as shown in Figure 1, when an AP MLD transmits PPDUs with different OFDM symbol lengths to a non-AP MLD, information on the transmission start time and OFDM symbol count of the previously transmitted PPDU is shared between links so that the transmission end times between links are synchronized. Accordingly, according to this disclosure, the AP MLD can adjust the length of the PPDU on the other link so that transmission ends simultaneously with the PPDU that started earlier, based on the information shared between links. This prevents deterioration of communication quality due to interference between the transmitted signal sent back on the link that has already finished transmission and the received signal on other links that have not yet finished transmission, when the receiving non-AP MLD is an NSTR.

[0046] Figure 3 shows a flowchart illustrating the process by which the communication device 200 (e.g., AP MLD) performs MLO (Multi-Link Ordering) to synchronize the transmission completion times across multiple links.

[0047] First, capability information is exchanged between MLDs (step S301).

[0048] Next, when an STA within the MLD acquires the right to transmit and begins transmitting a PPDU, the STAs within the MLD exchange information regarding the length of the PPDU (step S302).

[0049] Next, using the information regarding the transmitted PPDU and the information regarding the PPDU scheduled to be transmitted, it is determined whether or not to control the transmission completion time of other STAs' PPDUs (step S303).

[0050] Then, if it is determined in the preceding step S303 to control the transmission end time of the PPDU of another STA (Yes in step S303), the PPDU length of the other STA is controlled (step S304).

[0051] Step S301: Cap Job Information Exchange The capability information to be exchanged in step S301 includes the following information:

[0052] (1) Is it possible to change the length of a PPDU during transmission and notify within the PPDU that the length has been changed? (2) If information regarding a change in the length of the PPDU is notified within the PPDU being received, can the demodulation and decoding operations be completed within the specified time based on that information? (3) Whether a pair of links can send and receive simultaneously (whether it is STR or NSTR). (3) Number of available links (4) Number of available radios

[0053] The following are possible locations where the above-mentioned capability information can be included. Figure 4 shows an example of a frame structure that includes capability information.

[0054] (1) Within the MLD common Info field, which stores information about the MLD within the Multi-link element. (2) Within the STAn Info field, which stores information for each STA within the Multi-Link element.

[0055] Furthermore, the following can be cited as timings for exchanging capability information:

[0056] (1) When establishing a connection between MLDs. (2) When sending or receiving beacons. (3) When transmitting data.

[0057] Step S302: Information exchange regarding PPDU length In step S302, when an STA within the MLD acquires transmission rights and begins transmitting a PPDU, information regarding the length of the PPDU is exchanged among the STAs within the MLD. The following are examples of the information regarding the length of the PPDU that is exchanged among the STAs within the MLD:

[0058] (1) Number of OFDM symbols (2) OFDM symbol length (guard interval length) (3) Transmission start time (or scheduled transmission start time) (4) Padding length The length of the padding is, for example, the following: (4-1) Length of the Paddig field within the trigger frame (4-2) Post-EOF A-MPDU (MAC Protocol Data Unit) padding length (4-3) Length of the Packet extension field (5)MCS(Modulation and Coding Scheme) (6) Number of MPDUs being aggregated (7) Transmission bandwidth (8) Number of transmission streams (9) Coding method (10) PPDU format (11) Whether the frame requesting the recipient to send back a PPDU contains a frame requesting carrier sense before the recipient sends the PPDU. Specifically, it is one of the following: (11-1) Whether or not the trigger frame contains a CS Required subfield=1 (11-2) RTS (Request To Send) or not (12) Transmit power (13) Presence or absence of Signal extension (14) How many LTFs (Long Training Fields) are included? (15) Whether or not it includes a high-priority frame

[0059] Step S303: Determination to perform transmission end time control. In step S303, the system uses information regarding the transmitted PPDU and information regarding the scheduled transmitted PPDU to determine whether or not to control the transmission completion time of other STAs' PPDUs.

[0060] The following information can be used to determine whether or not to implement PPDU transmission end time control regarding the scheduled transmission of PPDUs:

[0061] (1) Number of OFDM symbols (2) OFDM symbol length (guard interval length) (3) Transmission start time (or scheduled transmission start time) (4) Padding length The length of the padding is, for example, the following: (4-1) Length of the Paddig field within the trigger frame (4-2) Post-EOF A-MPDU padding length (4-3) Length of the Packet extension field (5)MCS(Modulation and Coding Scheme) (6) Number of MPDUs being aggregated (7) Transmission bandwidth (8) Number of transmission streams (9) Coding method (10) PPDU format (11) Whether the frame requesting the recipient to send back a PPDU contains a frame requesting carrier sense before the recipient sends the PPDU. Specifically, it is one of the following: (11-1) Whether or not the trigger frame contains a CS Required subfield=1 (11-2) RTS (Request To Send) or not (12) Transmit power (13) Presence or absence of Signal extension (14) How many LTFs does it contain? (15) Whether or not it includes a high-priority frame (16) Number of frames in the buffer for each access category (17) Number of retransmissions

[0062] The decision to implement PPDU transmission end time control is made based on at least one of the following pieces of information: Capability information obtained in step S301, information on transmitted PPDUs obtained in step S302, and information on scheduled transmitted PPDUs.

[0063] For an AP MLD to control the PPDU transmission completion time, it must have the capability to change the length of the PPDU and notify that the length within the PPDU has been changed. Furthermore, the non-AP MLD receiving the transmission must have the capability to complete demodulation and decoding operations within a specified time based on the information provided in the received PPDU regarding the change in the PPDU's length.

[0064] Furthermore, the assumption that the link pair performing MLO is an NSTR link pair for the receiving non-AP MLD can also be used as a prerequisite for controlling the PPDU transmission end time. This is because, if it is an STR link pair for the non-AP MLD, even if the transmission end times of link1 and link2 do not match, there will be no degradation of communication quality due to inter-link interference, and therefore there is no need to share information between links or adjust the transmission start time.

[0065] Basically, the system calculates the transmission completion time of the transmitted PPDU based on the information about the transmitted PPDU, calculates the scheduled transmission completion time of the scheduled PPDU based on the information about the transmitted PPDU, and then calculates the difference between these two completion times. If the difference exceeds a predetermined time, it is determined to implement PPDU length control. If the frame requesting the recipient to return the PPDU contains a frame requesting carrier sense from the recipient before the PPDU is transmitted, the predetermined time difference is set to 4 microseconds; otherwise, the predetermined time difference is set to 8 microseconds.

[0066] Here, the type of frame included in the transmitted PPDU or the transmitted PPDU may be determined to determine whether or not to perform PPDU length control. For example, if the transmitted PPDU that finishes transmission first contains a high-priority frame, it may be determined that PPDU length control should not be performed. This is to avoid delaying the transmission completion time of the high-priority frame due to adjusting the PPDU length with unnecessary padding, etc.

[0067] Furthermore, when it is determined that PPDU length control should be implemented, it is also determined, based on Capability information, information about the transmitted PPDU, and information about the PPDU scheduled to be transmitted, whether to apply the length control to the PPDU that was first transmitted or the PPDU scheduled to be transmitted. If the destination terminal of the transmitted PPDU is capable of receiving when the PPDU length changes during reception, it may be determined that the length of the previously transmitted PPDU should be controlled.

[0068] Step S304: PPDU length control If it is determined in step S303 to control the transmission end time, the PPDU length control is performed.

[0069] When implementing PPDU length control, the system controls the inclusion of information within the PPDU indicating that the PPDU length will be changed. Possible locations for this information include the following:

[0070] (1) Within the Aggregated Control (A-Control) field (2) Frame body

[0071] Methods for controlling the transmission timing of PPDUs can be broadly categorized into two types: one that lengthens the length of one PPDU to match the transmission end time of other STAs' PPDUs, and another that shortens the length of one PPDU to match the transmission end time of other STAs' PPDUs.

[0072] The following are examples of control methods to lengthen or shorten the length of a PPDU so that it matches the transmission end time of other STAs' PPDUs:

[0073] (1) Set the OFDM symbol length of the PPDU transmitted by one STA to an integer multiple of the OFDM symbol length of the PPDU transmitted by the other STA. (2) Adjust the number of OFDM symbols. (3) Adjust the length of the padding.

[0074] Of the above, when adjusting the padding length, adjust the length of the padding field in the trigger frame, the length of the post-EOF A-MPDU padding, or the length of the packet extension field.

[0075] Furthermore, the control to shorten the length of a PPDU so that it matches the transmission end time of other STAs is performed by stopping the transmission of the PPDU.

[0076] D. Example of a communication sequence When two MLDs communicate using two links, the following two possible PPDU transmission sequences are expected:

[0077] (1) When the PPDU to be sent first is an HE / EHT PPDU (2) When the PPDU to be sent first is a non-HE PPDU

[0078] Furthermore, the following two scenarios are anticipated as targets for implementing PPDU transmission end time control.

[0079] (1) Control the length of the PPDU to be sent first. (2) Control the PPDU length of the next PPDU to be transmitted.

[0080] The following describes two communication sequence examples where the PPDU transmitted first is an HE / EHT PPDU.

[0081] Communication sequence example 1: The PPDU to be transmitted first is an HE / EHT PPDU, and the PPDU length of the HE / EHT PPDU transmitted first is controlled. Communication sequence example 2: The PPDU transmitted first is an HE / EHT PPDU, and the PPDU length of the non-HE PPDU transmitted later is controlled.

[0082] Note that we will omit the explanation of the communication sequence example where the PPDU transmitted first is a non-HE PPDU, but please understand that it operates in the same way as the communication sequence example described below, with only the information exchanged and the control execution judgment results differing.

[0083] Furthermore, MLDs may communicate with each other using three or more links. For example, an EHT PPDU (PPDU1) may be sent first, followed by a non-HE PPDU (PPDU2) whose PPDU length is adjusted to match the transmission end time of the EHT PPDU, and then a new EHT PPDU (PPDU3) may be sent, with its PPDU length adjusted to match the transmission end times of PPDU1 and PPDU2.

[0084] D-1. Communication Sequence Example 1 Section D-1 describes an example of a communication sequence in which the first transmitted PPDU is an HE / EHT PPDU, and the PPDU length of the previously transmitted HE / EHT PPDU is controlled.

[0085] Figure 5 shows an example of a communication sequence when an STR AP MLD containing STA1 and STA2 transmits a DL PPDU to an NSTR non-AP MLD. The link used by STA1 is designated as link1, and the link used by STA2 is designated as link2. Furthermore, it is assumed that the PPDU transmitted first by STA1 is an EHT / HE PPDU (PPDU1), and the PPDU transmitted later by STA2 is a non-HE PPDU (PPDU2). It is also assumed that each PPDU does not contain a high-priority frame.

[0086] Before the start of the communication sequence shown in Figure 5, for example, when the AP MLD and non-AP MLD connect, they exchange capability information indicating that the link1 and link2 pair is an STR link pair for the AP MLD and an NSTR link pair for the non-AP MLD. Furthermore, they exchange capability information indicating whether or not it is possible to adjust the PPDU length and decode the PPDU with the adjusted length. Note that if the link1 and link2 pair is not an NSTR link pair for the non-AP MLD (i.e., it is an STR link pair), then even if the transmission end times of link1 and link2 do not match, there will be no degradation of communication quality due to inter-link interference, so there is no need to share information between links or adjust the transmission start times.

[0087] Then, in the communication sequence shown in Figure 5, first, MAC lower sublayer #1 of STA1 sends a primitive called PHY-TXSTART.request(TXVECTOR) to PHY sublayer #1, requesting the start of PSDU (Physical Layer Service Data Unit) transmission. At this time, TIME_OF_DEPARTURE_REQUESTED=true is set in PHY-TXSTART.request so that information regarding the transmission start time is included in PHY-TXSTART.confirm(TXSTATUS) sent from PHY sublayer #1.

[0088] STA1's PHY sublayer#1 notifies MAC lower sublayer#1 of information regarding the transmission start time using PHY-TXSTART.confirm(TXSTATUS). Here, the information regarding the transmission start is TIME_OF_DEPARTURE, TIME_OF_DEPARTURE_ClockRate, and TX_START_OF_FRAME_OFFSET. TIME_OF_DEPARTURE is between 0 and 2 32 A value expressed in units of 1 / TIME_OF_DEPARTURE_ClockRate, ranging from -1, indicating the time the frame's energy was transmitted from the antenna. TIME_OF_DEPARTURE_ClockRate is expressed in MHz, ranging from 0 to 2. 16 The value is in the range of -1. TX_START_OF_FRAME_OFFSET is expressed in units of 10 nanoseconds, from 0 to 2. 32 A value in the range of -1 is an estimate of the time from when the preamble started transmitting from the antenna until this primitive was sent to MAC lower sublayer #1. This allows MAC lower sublayer #1 of STA1 to know precisely when PHY sublayer #1 started transmitting the frame.

[0089] Next, MAC lower sublayer #1 of STA1 notifies MAC lower sublayer #2 of STA2 via the Common entity of information about the PPDU (PPDU1) being transmitted by STA1. This information includes the number of OFDM symbols in PPDU1, the length of each OFDM symbol, the length of the PE (Packet Extension) field, the transmission start time, and whether or not a Trigger frame with CS required=1 is included in PPDU1. Based on this, MAC lower sublayer #2 of STA2 can calculate the transmission end time (T1) of PPDU1.

[0090] When STA2 acquires transmission rights on link2, STA2's MAC lower sublayer#2 sends a PHY-TXSTART.request(TXVECTOR) primitive to PHY sublayer#2, requesting the transmission of PPDU (PPDU2). At this time, as with STA1, TIME_OF_DEPARTURE_REQUESTED=true is set in PHY-TXSTART.request so that information regarding the transmission start time is included in PHY-TXSTART.confirm(TXSTATUS) sent from PHY sublayer#2. This allows STA2's MAC lower sublayer#2 to accurately know the transmission start time (T2) of PPDU2.

[0091] After receiving PHY-TXSTART.confirm(TXSTATUS) from PHY sublayer#2, MAC lower sublayer#2 of STA2 notifies MAC lower sublayer#1 of STA1 via the Common entity of information regarding the transmission of PPDU2. This information includes the number of OFDM symbols in the PPDU2, the length of each OFDM symbol, and the transmission start time. This allows MAC lower sublayer#1 of STA1 to calculate the transmission end time (T2) of PPDU2.

[0092] STA1's MAC lower sublayer#1 compares the transmission end time T1 of PPDU1 with the transmission end time T2 of PPDU2, and controls the transmission (PPDU length) of PPDU1 based on the comparison result.

[0093] If T2-8 microseconds ≤ T1 ≤ T2+8 microseconds (or T2-4 microseconds ≤ T1 ≤ T2+4 microseconds if PPDU1 includes a trigger frame with CS Required=1), STA1's MAC lower sublayer#1 does not control the PPDU length for PPDU1 transmissions.

[0094] When T1 > T2 + 8 microseconds (when PPDU1 contains a Trigger frame with CS Required = 1, then T1 > T2 + 4 microseconds), that is, when the transmission end time of PPDU1 is later than the transmission end time of PPDU2 by a predetermined time or more, the MAC lower sublayer#1 of STA1 instructs the PHY sublayer#1 to stop the transmission of PPDU1 so that the transmission end time of PPDU1 becomes T2 ± 8 microseconds. At this time, in order for an immediate response to be transmitted from the non-AP MLD after SIFS after stopping the transmission of PPDU1, the new Length of PPDU1 is notified within the MPDU. The location for describing the new Length of PPDU1 is the A-Control field or the Frame Body within the HT-Control field. On the non-AP MLD side of the destination, based on this description, the demodulation and decoding operations of PPDU1 with the changed length can be completed within the specified time.

[0095] When T1 < T2 - 8 microseconds (when PPDU1 contains a Trigger frame with CS Required = 1, then T1 < T2 - 4 microseconds), that is, when the transmission end time of PPDU1 is earlier than the transmission end time of PPDU2 by a predetermined time or more, the MAC lower sublayer#1 of STA1 performs Padding on PPDU1 so that the transmission end time T1 of PPDU1 becomes T2 -  8 microseconds or more (when PPDU1 contains a Trigger frame with CS Required = 1, then T1 becomes T2 - 4 microseconds or more). At this time, when the time requiring adjustment is 16 microseconds or less (the difference between T2 - 8 microseconds and T1 is within 16 microseconds, that is, the difference between T2 and T1 is within 24 microseconds), the transmission end time of PPDU1 may be adjusted by extending the PacketExtension field. Also, at this time, the new Length of PPDU1 is notified within PPDU1.

[0096] As a result, the transmission end time of PPDU1 can be aligned with the transmission end time of PPDU2, allowing communication within the NSTR non-AP MLD without simultaneous reception of DL PPDUs and transmission of immediate responses.

[0097] D-2. Communication Sequence Example 2 Section D-2 describes an example of a communication sequence in which the first transmitted PPDU is an HE / EHT PPDU, and the second transmitted PPDU is a non-HE PPDU. The number of OFDM symbols, OFDM symbol length, and transmission start time of the HE / EHT PPDU transmitted on each link are shared between links, and the number of OFDM symbols and OFDM symbol length of the non-HE PPDU transmitted later are adjusted accordingly. In the following explanation, it is assumed that the OFDM symbol length of the HE / EHT PPDU is transmitted at 16 microseconds.

[0098] Figure 6 shows an example of a communication sequence when an STR AP MLD containing STA1 and STA2 transmits a DL PPDU to an NSTR non-AP MLD. However, the link used by STA1 is designated as link1, and the link used by STA2 is designated as link2. Furthermore, it is assumed that the PPDU transmitted first by STA1 is an EHT / HE PPDU (PPDU1), and the PPDU transmitted later by STA2 is a non-HE PPDU (PPDU2). It is also assumed that each PPDU does not contain a high-priority frame.

[0099] Before the start of the communication sequence shown in Figure 6, for example, when the AP MLD and non-AP MLD connect, they exchange capability information indicating that the link1 and link2 pair is an STR link pair for the AP MLD and an NSTR link pair for the non-AP MLD. Furthermore, they exchange capability information indicating whether or not it is possible to adjust the PPDU length and decode the PPDU with the adjusted length. Note that if the link1 and link2 pair is not an NSTR link pair for the non-AP MLD (i.e., it is an STR link pair), then even if the transmission end times of link1 and link2 do not match, there will be no degradation of communication quality due to inter-link interference, so there is no need to share information between links or adjust the transmission start times.

[0100] Then, in the communication sequence shown in Figure 6, first, MAC lower sublayer#1 of STA1 sends a primitive called PHY-TXSTART.request(TXVECTOR) to PHY Sublayer#1, requesting the start of transmission of PSDU#1-1. At this time, TIME_OF_DEPARTURE_REQUESTED=true is set in PHY-TXSTART.request so that information regarding the transmission start time is included in PHY-TXSTART.confirm(TXSTATUS) sent from PHY sublayer#1.

[0101] STA1's PHY sublayer#1 notifies MAC Lower Sublayer#1 of information regarding the transmission start time using PHY-TXSTART.confirm(TXSTATUS). This allows STA1's MAC lower sublayer#1 to know exactly when PHY sublayer#1 started transmitting frames.

[0102] Next, MAC lower sublayer #1 of STA1 notifies MAC lower sublayer #2 of STA2 via the Common entity about the PPDU (PPDU1) that STA1 is sending. This allows MAC Lower Sublayer #2 of STA2 to calculate the end time (T1) of PPDU1.

[0103] When STA2 acquires transmission rights on link2, STA2's MAC Lower Sublayer#2 sends a PHY-TXSTART.request(TXVECTOR) primitive to PHY sublayer#2, requesting the transmission of PPDU (PPDU2).

[0104] In this case, STA2's MAC Lower Sublayer#2 determines whether to adjust the transmission end time of PPDU1 or PPDU2 based on Capability information, information regarding the transmission of PPDU1, information regarding the planned transmission of PPDU2 that it holds, and Capability information of the terminal (non-AP MLD) to which PPDU2 will be sent (whether or not it supports receiving non-HE PPDUs with adjusted PPDU lengths). At this time, STA2's MAC Lower Sublayer#2 may also calculate the planned transmission end time (T2) when the PPDU is constructed using each of the various symbol lengths it supports.

[0105] MAC Lower Sublayer #2 of STA2 may set the GI length of PPDU2 according to the length of each OFDM symbol notified by MAC Lower Sublayer #1 of STA1 as an adjustment for the transmission end time. Specifically, it may set [GI length of PPDU1, GI length of PPDU2] = [1.6 microseconds, 0.4 microseconds], [3.2 microseconds, 0.8 microseconds], and set [OFDM symbol length of PPDU1, OFDM symbol length of PPDU2] = [14.4 microseconds, 3.6 microseconds], [16.0 microseconds, 4.0 microseconds] so that the OFDM symbol length of PPDU1 is an integer multiple of the OFDM symbol length of PPDU2. This reduces the discrepancy in transmission end times caused by differences in GI length, and simplifies the process of matching transmission end times. For example, by simply adjusting the number of OFDM symbols in PPDU2 so that it does not exceed 4n-3 times the number of OFDM symbols in PPDU1 (where n is any natural number), the difference in transmission end times between PPDU1 and PPDU2 can be reduced to within 8 microseconds.

[0106] In this example communication sequence, the OFDM symbol length of PPDU2 is set to one-quarter of the OFDM symbol length of PPDU1, the OFDM symbol length of PPDU2 is set to 4.0 microseconds, and the number of OFDM symbols in PPDU2 is controlled to be 4n times the number of OFDM symbols in PPDU1 before transmission.

[0107] As a result, the transmission end time of PPDU2 can be aligned with the transmission end time of PPDU1, allowing communication within the NSTR non-AP MLD without simultaneous occurrence of DL PPDU reception and immediate response transmission.

[0108] E. Effects Section E summarizes the effects of this disclosure.

[0109] According to this disclosure, information regarding the length of PPDUs transmitted over a link can be shared within an MLD, and the number of OFDM symbols in a PPDU can be adjusted so that non-HE PPDU transmissions finish simultaneously. Therefore, even when transmitting PPDUs with different OFDM symbol lengths to a non-STR MLD, it is possible to generate and transmit PPDUs that satisfy the end-time alignment requirement, thereby preventing reception failures due to inter-link interference in non-STR MLDs.

[0110] Specifically, when performing MLO between AP MLD and non-AP MLD, the transmission start time and number of OFDM symbols of previously transmitted PPDUs are shared between links so that the transmission end times are synchronized between links when AP MLD sends PPDUs with different OFDM symbol lengths to Non-AP MLD. Therefore, based on the shared information, the PPDU length of either the previously transmitted PPDU or the PPDU scheduled for transmission can be adjusted so that the difference in transmission end times between each link is within a predetermined time. The receiving NSTR non-AP MLD can avoid situations where it fails to receive DL PPDUs on the other link due to simultaneous transmission of immediate responses on one link. [Industrial applicability]

[0111] The present disclosure has been described in detail above with reference to specific embodiments. However, it will be obvious that those skilled in the art can modify or substitute these embodiments without departing from the gist of the present disclosure.

[0112] This specification has primarily described embodiments of applying the disclosure to a communication system that performs multilink operation by pairing a link that transmits non-HE PPDUs based on an IEEE 802.11ax or earlier format with a link that transmits HE / EHT PPDUs based on an IEEE 802.11ax or later format. However, the gist of this disclosure is not limited thereto. The disclosure can be applied to various types of communication systems that perform multilink operation by pairing links that transmit data frames of different formats, and similarly, the effect of aligning the transmission end times between links by adjusting the data frame length can be obtained.

[0113] In short, this disclosure has been explained in the form of examples, and the contents of this specification should not be interpreted restrictively. The claims should be considered in order to determine the gist of this disclosure.

[0114] Furthermore, this disclosure may also take the following form.

[0115] (1) A first communication unit that communicates via the first link, A second communication unit that communicates via the second link, A control unit that controls the communication operation using the first link and the second link by the first communication unit and the second communication unit, It is equipped with, The control unit controls the transmission frame length in the first link or the second link when the first communication unit starts transmitting first on the first link. Communication device.

[0116] (2) The control unit controls the transmission frame length in the first link or the second link based on information relating to the transmission data that the first communication unit has started transmitting and information relating to the transmission data that the second communication unit is scheduled to transmit. The communication device described in (1) above.

[0117] (3) The information relating to the transmitted data includes at least the OFDM symbol length, the number of OFDM symbols, and the transmission start time (including the scheduled transmission start time). The communication device described in (2) above.

[0118] (4) The control unit controls the transmission frame length so that the difference between the transmission end time on the first link by the first communication unit and the scheduled transmission end time on the second link by the second communication unit is less than a predetermined value. A communication device as described in any of (1) to (3) above.

[0119] (5) The predetermined value is determined based on whether the frame that requests the recipient to return a frame contains a frame that requests carrier sense before the recipient sends the frame. The communication device described in (4) above.

[0120] (6) The control unit determines whether or not to perform control of the transmission frame length based on whether the first communication unit or the second communication unit has the capability to change the transmission frame length for adjusting the transmission end time and to notify that the transmission frame length has been changed. A communication device as described in any of (1) through (5) above.

[0121] (7) The control unit determines whether or not to perform control of the transmission frame length based on the capability information of the communication device to which the data using the first link and the second link is transmitted. The communication device described in (1) above.

[0122] (8) The control unit determines whether or not to perform control of the transmission frame length based on whether the destination communication device can complete demodulation and decoding operations within a predetermined time in response to the notification regarding the change in the transmission frame length. The communication device described in (7) above.

[0123] (9) The control unit determines whether or not to implement control of the transmission frame length when the first link and the second link form a pair of links that impose constraints on the receiving communication device when they transmit and receive simultaneously. A communication device as described in either (7) or (8) above.

[0124] (10) The control unit determines whether or not to perform control of the transmission frame length based on information relating to the transmission data that the first communication unit has started transmitting on the first link, or information relating to the transmission data that the second communication unit is scheduled to transmit on the second link. A communication device as described in any of (1) through (9) above.

[0125] (11) The control unit determines whether or not to perform control of the transmission frame length based on the type of transmission data that the first communication unit has started transmitting on the first link or the type of transmission data that the second communication unit is scheduled to transmit on the second link. The communication device described in (10) above.

[0126] (12) The control unit determines that it will not perform the control of the transmission frame length if the transmission data that is to be transmitted first contains data with a higher priority. The communication device described in (11) above.

[0127] (13) The control unit determines whether to control the frame length of the frame that was first transmitted or the frame that is scheduled to be transmitted. The communication device described in (11) above.

[0128] (13-1) The control unit determines whether or not to control the frame length of the frame that was first transmitted, based on whether or not the terminal receiving the frame is capable of receiving when the frame length being received is changed. The communication device described in (13) above.

[0129] (14) When the control unit performs control of the transmission frame length, it includes information regarding the change of the transmission frame length within the transmission frame. A communication device as described in any of (1) through (13) above.

[0130] (15) The control unit may perform control to lengthen the transmission frame length of one link so that it matches the transmission end time of the other link, or to shorten the transmission frame length of one link so that it matches the transmission end time of the other link. A communication device as described in any of (1) through (14) above.

[0131] (16) The control unit sets the OFDM symbol length of the transmission frame in one link to a length that is an integer multiple of the OFDM symbol length of the transmission frame in the other link, and lengthens or shortens the transmission frame length of one link so that it matches the transmission end time in the other link. The communication device described in (15) above.

[0132] (17) The control unit adjusts either the number of OFDM symbols or the padding length to lengthen or shorten the transmission frame length of one link so that it matches the transmission end time of the other link. The communication device described in (15) above.

[0133] (18) The control unit stops frame transmission on one link so as to coincide with the end time of transmission on the other link. The communication device described in (15) above.

[0134] (19) Either the first communication unit or the second communication unit transmits an HE / EHT PPDU, and the other transmits a non-HE PPDU. A communication device as described in any of (1) through (18) above.

[0135] (20) A communication method in which a communication device communicates using a first link and a second link, The first step is to start sending using the aforementioned link, A step of controlling the transmission frame length in the first link or the second link so that the difference between the transmission end time in the first link and the scheduled transmission end time in the second link is less than a predetermined value, A communication method that includes [something]. [Explanation of symbols]

[0136] 200...Communication device, 210...Communication unit, 211...Communication control unit 212...Communication storage unit, 213...Common data processing unit 214... Individual data processing unit, 215... Signal processing unit 216...Wireless interface unit, 217...Amplifier unit, 220...Control unit 230...Memory unit, 240...Antenna

Claims

1. A first communication unit that communicates via the first link, A second communication unit that communicates via the second link, A control unit that controls the communication operation using the first link and the second link by the first communication unit and the second communication unit, It is equipped with, The control unit controls the transmission frame length on the first link or the second link when the first communication unit starts transmitting first, based on information regarding the transmission data that the first communication unit has started transmitting and information regarding the transmission data that the second communication unit is scheduled to transmit. Communication device.

2. The information relating to the transmitted data includes at least the OFDM symbol length, the number of OFDM symbols, and the transmission start time (including the scheduled transmission start time). The communication device according to claim 1.

3. The control unit controls the transmission frame length so that the difference between the transmission end time on the first link by the first communication unit and the scheduled transmission end time on the second link by the second communication unit is less than a predetermined value, if the difference between the transmission end time and the scheduled transmission end time is less than a predetermined value. The communication device according to claim 1.

4. The predetermined value is determined based on whether the frame that requests the recipient to return a frame contains a frame that requests carrier sense before the recipient sends the frame. The communication device according to claim 3.

5. The control unit determines whether or not to perform control of the transmission frame length based on whether the first communication unit or the second communication unit has changed the transmission frame length for adjusting the transmission end time and has the capability to notify that the transmission frame length has been changed. The communication device according to claim 1.

6. The control unit determines whether or not to perform control of the transmission frame length based on the capacity information of the communication device to which the data using the first link and the second link is transmitted. The communication device according to claim 1.

7. The control unit determines whether or not to perform control of the transmission frame length based on whether the destination communication device can complete demodulation and decoding operations within a predetermined time in response to a notification regarding a change in the transmission frame length. The communication device according to claim 6.

8. The control unit determines whether or not to implement control over the transmission frame length when the first link and the second link form a pair of links that impose constraints on the receiving communication device when they transmit and receive simultaneously. The communication device according to claim 6.

9. The control unit determines whether or not to perform control of the transmission frame length based on information regarding the transmission data that the first communication unit has started transmitting on the first link, or information regarding the transmission data that the second communication unit is scheduled to transmit on the second link. The communication device according to claim 1.

10. The control unit determines whether or not to perform control of the transmission frame length based on the type of transmission data that the first communication unit has started transmitting on the first link or the type of transmission data that the second communication unit is scheduled to transmit on the second link. The communication device according to claim 9.

11. The control unit determines that it will not perform the transmission frame length control if the transmission data that is to be transmitted first contains data with a higher priority. The communication device according to claim 10.

12. The control unit determines whether to control the frame length of the frame that was first transmitted or the frame that is scheduled to be transmitted. The communication device according to claim 10.

13. When the control unit performs control of the transmission frame length, it includes information regarding the change in the transmission frame length within the transmission frame. The communication device according to claim 1.

14. The control unit performs control to lengthen the transmission frame length of one link so that it matches the transmission end time of the other link, or to shorten the transmission frame length of one link so that it matches the transmission end time of the other link. The communication device according to claim 1.

15. The control unit sets the OFDM symbol length of the transmission frame in one link to an integer multiple of the OFDM symbol length of the transmission frame in the other link, and lengthens or shortens the transmission frame length of one link so that it matches the transmission end time in the other link. The communication device according to claim 14.

16. The control unit adjusts either the number of OFDM symbols or the padding length to lengthen or shorten the transmission frame length of one link so that it matches the transmission end time of the other link. The communication device according to claim 14.

17. The control unit stops frame transmission on one link so as to coincide with the end time of transmission on the other link. The communication device according to claim 14.

18. One of the first communication unit or the second communication unit transmits an HE / EHT PPDU, and the other transmits a non-HE PPDU. The communication device according to claim 1.

19. A communication method in which a communication device communicates using a first communication unit that communicates over a first link and a second communication unit that communicates over a second link, The first communication unit initiates transmission via the first link, A step of controlling the transmission frame length on the first link or the second link when the first communication unit starts transmitting first, based on information regarding the transmission data that the first communication unit has started transmitting and information regarding the transmission data that the second communication unit is scheduled to transmit. A communication method that includes [something].

20. A first communication unit that communicates via the first link, A second communication unit that communicates via the second link, A control unit that controls the communication operation using the first link and the second link by the first communication unit and the second communication unit, It is equipped with, The control unit determines whether or not to control the transmission frame length on the first link or the second link when the first communication unit starts transmitting on the first link, based on information regarding the transmission data that the first communication unit has started transmitting on the first link, or information regarding the transmission data that the second communication unit is scheduled to transmit on the second link. Communication device.

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