communication equipment

Abstract

The present technology relates to a communication device with which it is possible to improve the opportunity of acquiring a transmission right in a plurality of links. A transmission device is provided that comprises a control unit for performing an exchange of frames with other communication devices using wireless communication utilizing a plurality of links and exercising control to: transmit, utilizing a first link, a first frame to the other communication devices that includes a request for acquiring a transmission right of the first link; generate, when a second frame transmitted from the other transmission devices utilizing the first link is received that includes permission for acquiring the transmission right of the first link, a third frame that includes information that induces the other communication devices to acquire the transmission right of a second link which is different from the first link; and transmit the third frame to the other communication devices utilizing the first link. The present technology may be applied to, for example, a communication device constituting a wireless LAN system.

Description

[Technical Field]

[0001] The present technology relates to a communication device, and more particularly to a communication device that can improve the chances of acquiring a transmission right on a plurality of links. [Background technology]

[0002] In recent years, with the spread of wireless LAN (Local Area Network), there has been a demand for an expansion of the frequency bandwidth used for transmission. Therefore, transmission over a wider frequency bandwidth by simultaneously using multiple frequency bands such as the 5 GHz and 6 GHz bands is being considered. This frequency band is called a link.

[0003] As a technique relating to transmission using a plurality of links, for example, the technique disclosed in Non-Patent Document 1 is known. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Yongho Seok, et al., "Proposed Draft Text for MLO Multi-Link Channel Access: PPDU End Time Alignment," IEEE 802.11-20 / 1271r8, Sep. 9, 2020 Summary of the Invention [Problem to be solved by the invention]

[0005] When receiving signals simultaneously over multiple links, the end times of the received signals on each link must be synchronized, which raises the risk that another terminal may acquire the transmission right before all links become available. Therefore, there is a need for a method to improve the chances of acquiring the transmission right over multiple links.

[0006] The present technology has been made in view of such circumstances, and is intended to improve the chances of acquiring the transmission right on a plurality of links. [Means for solving the problem]

[0007] A communication device according to one aspect of the present technology exchanges frames with other communication devices wirelessly using multiple links, transmits a first frame to the other communication device using a first link, the first frame including a request to acquire transmission rights for the first link, and when receiving a second frame including permission to acquire transmission rights for the first link transmitted from the other communication device using the first link, generates a third frame including information that induces the other communication device to acquire transmission rights for a second link different from the first link, and is equipped with a control unit that controls the transmission of the third frame to the other communication device using the first link.

[0008] In a communication device according to one aspect of the present technology, frames are exchanged with other communication devices via wireless communication using multiple links, and a first frame including a request to acquire transmission rights for a first link is transmitted to the other communication device using a first link, and when a second frame including permission to acquire transmission rights for the first link is received from the other communication device using the first link, a third frame including information that induces the other communication device to acquire transmission rights for a second link different from the first link is generated, and the third frame is transmitted to the other communication device using the first link.

[0009] A communication device according to one aspect of the present technology exchanges frames with other communication devices wirelessly using multiple links, and when it receives a first frame transmitted from the other communication device using a first link and including a request to acquire transmission rights for the first link, it transmits a second frame to the other communication device using the first link and including permission to acquire transmission rights for the first link, and when it receives a third frame transmitted from the other communication device using the first link and including information that induces acquisition of transmission rights for a second link different from the first link, it generates a fifth frame including information indicating the transmission rights acquired for the second link, and is equipped with a control unit that controls the transmission of the fifth frame to the other communication device using the first link.

[0010] In a communication device according to one aspect of the present technology, frames are exchanged with other communication devices via wireless communication using multiple links; when a first frame including a request to acquire transmission rights for the first link is received from the other communication device using a first link, a second frame including permission to acquire transmission rights for the first link is sent to the other communication device using the first link; when a third frame including information inducing acquisition of transmission rights for a second link different from the first link is received from the other communication device using the first link, a fifth frame including information indicating the transmission rights acquired for the second link is generated, and the fifth frame is sent to the other communication device using the first link.

[0011] It should be noted that the communication device according to one aspect of the present technology may be an independent device or an internal block constituting a single device. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 10 is a diagram showing frames transmitted by each terminal in time sequence. [Figure 2] FIG. 10 is a diagram showing frames transmitted by each terminal in time sequence. [Figure 3] 1 is a diagram illustrating an example of the configuration of a wireless network system to which the present technology is applied. [Figure 4] 1 is a block diagram illustrating a configuration example of a communication device to which the present technology is applied. [Figure 5] FIG. 10 is a diagram illustrating an example of an entire sequence. [Figure 6] FIG. 10 is a diagram illustrating an example of transmission in DL Transmission. [Figure 7] FIG. 10 is a diagram illustrating an example of the configuration of a frame notified in Capabilities Exchange. [Figure 8] This is a diagram showing the frames transmitted by each terminal in a time series in a series of processes after Capabilities Exchange. [Figure 9] FIG. 10 is a diagram illustrating an example of the configuration of a Support Link CTS Trigger frame. [Figure 10] FIG. 10 is a diagram illustrating an example of the configuration of a Support Link CTS-A frame. [Figure 11] FIG. 10 is a diagram illustrating an example of the configuration of an Ack+Trigger frame. [Figure 12] 10 is a diagram showing frames transmitted by each terminal in time sequence when uplink transmission precedes downlink transmission. [Figure 13] FIG. 10 is a diagram illustrating an example of the structure of a frame included in a data unit when DL Transmission is performed. [Figure 14] 10 is a diagram showing in chronological order the frames transmitted by each terminal when the CTS-A frame is not correctly received by STR AP MLD on the second link. [Figure 15] FIG. 10 is a diagram showing, in time sequence, frames transmitted by each terminal when the transmission right acquired in the second link is released. [Figure 16] FIG. 10 is a diagram illustrating an example of the configuration of a Support Link End frame. [Figure 17] 10 is a flowchart illustrating the flow of processing performed in non-STR non-AP MLD. [Figure 18] 10 is a flowchart illustrating the flow of processing performed in STR AP MLD. DETAILED DESCRIPTION OF THE INVENTION

[0013] (Overview of this technology) In wireless LANs, in the unlicensed band, within one basic service set (BSS), an access point (AP (Access Point) or BS (Base Station)) and a user terminal (STA (Station) or UE (User Equipment)) autonomously acquire the right to transmit within the BSS and communicate.

[0014] In recent years, the amount of data handled in high-definition video transmissions such as AR (Augmented Reality), VR (Virtual Reality), 4K, and 8K has become extremely large, requiring further improvements in transmission capacity in wireless transmissions and an expansion of the frequency bandwidth used for transmission. 4K has approximately 4,000 pixels in the horizontal direction, and 8K has approximately 8,000 pixels in the horizontal direction.

[0015] However, the unlicensed frequency band is limited, making it difficult to secure a wide frequency bandwidth. Against this backdrop, the IEEE 802.11 Task Group (TG) be is considering transmission over a substantially wider frequency bandwidth by simultaneously using multiple frequency bands, such as the 5 GHz and 6 GHz bands.

[0016] Here, a frequency band is also called a link, and a terminal that can transmit using multiple frequency bands, i.e., multiple links simultaneously, is called an MLD (Multi-Link Device). In particular, an access point and user terminal that are MLDs are called as follows:

[0017] That is, an access point (AP) that is an MLD is called an AP MLD (Access Point Multi-Link Device), and a user terminal (STA) that is an MLD is called a non-AP MLD (non-Access Point Multi-link Device).

[0018] The term "transmitting using multiple links simultaneously" mentioned here does not mean transmitting by controlling multiple links independently, but rather means separately controlling the communication operations between multiple links in order to improve communication quality. For example, the purpose is to achieve the following operations:

[0019] That is, the objective can be, first, to transmit synchronized signals across multiple links, and, second, to perform uplink transmission from a user terminal to an access point on one link and downlink transmission from the access point to the user terminal on a different link.

[0020] Note that a link refers to a wireless transmission path over which data can be transmitted between two communication devices, and each link may use a different frequency band.

[0021] In this case, since there are terminals that can transmit over multiple links and terminals that can only transmit over a single frequency, it is possible to acquire the transmission right for each frequency band. Also, it is possible that one user terminal may perform uplink transmission to an access point in the 5 GHz band and downlink transmission in the 6 GHz band, or may perform only uplink transmission or only downlink transmission over both links.

[0022] In other words, it is assumed that multiple links will be used, with transmission and reception performed on each link (STR: Simultaneous Transmit and Receive), or that either transmission or reception will be performed between multiple links (NSTR: non-STR).

[0023] According to the above-mentioned Non-Patent Document 1 (hereinafter referred to as Document 1), when non-AP MLD performs STR, the signal it transmits leaks into the signal it receives, causing self-interference and degrading communication quality. This problem is caused by, for example, the following factors.

[0024] That is, first, the proximity between links (frequency bands); second, when non-AP MLD uses different antennas for each link, the correlation between non-AP MLD antennas and the characteristics of the bandpass filters attached to the antennas are factors.

[0025] The non-AP MLD in which the above problem occurs is defined as a terminal that does not implement STR, and is defined as non-STR non-AP MLD or NSTR limited (STA is NSTR limited).

[0026] However, because it depends not only on the terminal profile but also on the links used at the same time, it may be controlled to operate as non-STR MLD on a specific link pair and as STR MLD on another link pair.In the following explanation, non-STR non-AP MLD is defined as "non-AP MLD that operates as non-STR for at least the link pair in question."

[0027] Here, when non-STR non-AP MLD receives signals from any one terminal simultaneously over multiple links, the reception end times of the received signals on each link must be the same.

[0028] This is because in a wireless LAN, it is common for a terminal to send an acknowledgement (Ack) to a received signal within a specified period after the end of reception. Therefore, if the end times of the received signals are not aligned, the user terminal will send an Ack on one of the multiple links, but will receive the signal on the other link, resulting in an unintentional STR.

[0029] The above signal is a data unit with a certain time width, and is called a PPDU (PHY Protocol Data Unit) in Reference 2. Reference 1 also states that the above specified period is set at approximately 16 us, although this value depends on the device implementation, and that when signals are sent using multiple links with the same non-STR non-AP MLD as the destination, the difference in the transmission end times of the signals on each link must be within 8 us.

[0030] Reference 2: IEEE Std 802.11 TM -2016

[0031] As mentioned above, when transmitting over multiple links for non-STR non-AP MLD, the reception termination time (or transmission end time of the transmission signal) of each link must be synchronized. Reference 3 defines the following two types of transmission methods to satisfy this requirement:

[0032] That is, first, synchronous transmission (Sync. TX: Synchronized Transmission) is defined as transmitting data between different links with the same start time of transmission, and second, asynchronous transmission (Asnyc TX: Asynchronized Transmission) is defined as transmitting data between different links without the same start time of transmission.

[0033] Document 3: Zhou Lan, et al., "MLO a-synchronize and synchronize operation discussions," IEEE 802.11-20 / 291r1 Jan. 20, 2020

[0034] Reference 1 mentions the conditions for implementing synchronous transmission. In wireless LANs, typically, each terminal cannot acquire the transmission right until a random waiting time (backoff) has expired. The above condition means that synchronous transmission is only performed when the transmission right has been acquired on each link after the backoffs on each of the multiple links have expired. This condition is necessary because backoff is determined by the degree of transmission congestion on each link, ensuring fairness for each link.

[0035] However, if there is a difference in the degree of congestion of transmissions on each link, the backoff applied to both links will be different. Therefore, when all backoffs on each link are completed, synchronous transmission will inevitably be performed in the most congested environment. Therefore, while waiting for the backoffs on all links to be completed before synchronous transmission is performed, other terminals may acquire the transmission right on some links, reducing the probability of performing synchronous transmission.

[0036] Therefore, by adopting asynchronous transmission, it is possible to acquire the transmission right from a link whose backoff has expired, improving the probability of multiple link transmission to non-STR non-AP MLD, which ultimately contributes to improving the throughput of the entire system.

[0037] In the following, the link that first obtained the transmission right will be referred to as the first link (Link 1), the link that later obtained the transmission right will be referred to as the second link (Link 2), and the data transmitted will be referred to as a PPDU (PHY Data Protocol Data Unit).

[0038] As a method for implementing the above-mentioned asynchronous transmission, Document 3 mentions the use of the following methods A to C.

[0039] A: Each link transmits PPDUs asynchronously after the backoff expires. B: After sending an RTS (Ready to send) frame on the first link, the first and second links receive a CTS (Clear to send) frame to acquire a TXOP (Transmission Opportunity) and send a PPDU. C: On the first link, after acquiring a TXOP by notifying an RTS frame and a CTS frame, a PPDU is transmitted, but on the second link, a PPDU is transmitted without transmitting an RTS frame and a CTS frame.

[0040] Methods B and C essentially have in common that they acquire the transmission right for each link before data transmission by sending RTS and CTS frames on the first link (Link 1). However, the frames transmitted on the second link (Link 2) differ depending on the time difference when the backoff expires on each link and the NSTR constraint.

[0041] Figure 1 shows, in time sequence, frames transmitted by each terminal when method B is applied. Figure 2 shows, in time sequence, frames transmitted by each terminal when method C is applied.

[0042] 1 and 2 show a case where the STR AP MLD and non-STR non-AP MLD transmit a data unit (PPDU) from the STR AP MLD to the non-STR non-AP MLD using two links, the first link (Link 1) and the second link (Link 2). In Figures 1 and 2, the upper side of the time axis for each of the first and second links represents frames transmitted by the STR AP MLD, and the lower side of the time axis represents frames transmitted by the non-STR non-AP MLD.

[0043] 1 shows a case where the difference between the backoff expiration time of the first link and the backoff expiration time of the second link in the STR AP MLD is shorter than the transmission period of the RTS frame. In this case, the CTS-A (Announcement) frame is transmitted from the STR AP MLD in the second link at the same time as the CTS frame is transmitted from the non-STR non-AP MLD in the first link.

[0044] The CTS-A frame can notify surrounding terminals that the transmitting terminal has acquired the transmission right. If an RTS frame is used instead of a CTS-A frame, non-STR non-AP MLD must transmit a CTS frame, but in this case, the CTS frame will be transmitted on the second link during the reception period of PPDU#1-1, so the NSTR constraints cannot be met.

[0045] It is also possible that the CTS-A frame may not be transmitted. In this case, however, there is a risk that another terminal may acquire the transmission right because no signal is transmitted from the STR AP MLD or non-STR non-AP MLD on the second link.

[0046] 2 shows a case where the difference between the backoff expiration time of the first link and the backoff expiration time of the second link in STR AP MLD is longer than the transmission period of the RTS frame. In this case, the second link transmits a data unit (PPDU) without transmitting an RTS frame or a CTS frame.

[0047] Strictly speaking, the case where the difference between the backoff expiration time of the first link and the backoff expiration time of the second link in STR AP MLD is longer than the transmission period of the RTS frame and the CTS frame is shown, but the same applies to the case where this time difference is "longer than the transmission period of the RTS frame but shorter than the transmission period of the RTS frame and the CTS frame."

[0048] In all of the methods described so far, the STR AP MLD acquires the transmission right. That is, in methods A to C, it is assumed that some frame will be transmitted after the STR AP MLD backoff expires.

[0049] However, in reality, due to the placement of surrounding terminals and the fact that the backoff expiration time is set randomly, there are cases where the backoff expires earlier in the non-STR non-AP MLD than in the STR AP MLD. In this case, the non-STR non-AP MLD acquires the transmission right, and by inducing data unit transmission from the STR AP MLD within that transmission right and transmitting the data unit, for example, the following effects can be obtained.

[0050] In other words, it improves the chances of acquiring transmission rights for multiple links in non-STR non-AP MLD and also improves the data rate within the system. However, the latter effect is essentially due to the reduction of transmission waiting time by adopting diversity in the backoff counter.

[0051] Hereinafter, the link (first link (Link 1)) through which STR AP MLD first transmits an RTS frame is defined as the basic link, and the link (second link (Link 2)) other than the basic link that STR AP MLD and non-STR non-AP MLD use for transmission is defined as the support link.

[0052] In order to solve the above-mentioned current problem, this technology proposes the following method: In other words, if the backoff counter of the non-STR non-AP MLD expires earlier than that of the STR AP MLD in the second link, the necessary control signal is transmitted so that the non-STR non-AP MLD can acquire the transmission right in the second link.

[0053] More specifically, the STR AP MLD sends an RTS frame to the non-STR non-AP MLD over the basic link, and when a CTS frame is returned from the non-STR non-AP MLD, it sends a Support Link CTS Trigger frame, which triggers the non-STR non-AP MLD to acquire the transmission right on the support link.

[0054] Furthermore, when a Support Link CTS Trigger frame is sent from the STR AP MLD over the basic link, the non-STR non-AP MLD returns a Support Link CTS-A frame over the basic link and simultaneously transmits a CTS-A frame over the support link, allowing the non-STR non-AP MLD to acquire the transmission right in advance over the support link.

[0055] Hereinafter, embodiments of the present technology will be described with reference to the drawings.

[0056] <1. Embodiments of the present technology>

[0057] (System configuration example) FIG. 3 is a diagram showing an example of the configuration of a wireless network system to which the present technology is applied.

[0058] 3, communication devices 10A to 10D exist in the wireless LAN system. The communication device 10A is a STR AP MLD (Simultaneous Transmit and Receive, Access Point Multi-Link Device). The communication device 10B is a non-STR non-AP MLD (non-Simultaneous Transmit and Receive, non-Access Point Multi-link Device). The communication devices 10C and 10D are non-AP STAs (non-Access Point Stations).

[0059] That is, in FIG. 3, communication device 10A, which is one access point (STR AP MLD), is connected to communication device 10B, which is one non-STR non-AP MLD, as well as communication devices 10C and 10D, which are non-AP STAs, which are terminals that are not access points.

[0060] However, a non-AP STA is defined as a terminal that is either a non-STR non-AP MLD, an STR non-AP MLD, or a non-AP STA that is not an MLD. While Fig. 3 shows a case where two non-AP STAs (non-AP STA 2 and non-AP STA 3) exist, the number of non-AP STAs may be other than this. That is, there may be no non-AP STAs other than the non-STR non-AP MLD (non-STR non-AP MLD 1 in Fig. 3), or there may be one, three, or more non-AP STAs other than the non-STR non-AP MLD.

[0061] In the following explanation, the set of non-AP STAs other than non-STR non-AP MLD 1 will be referred to as STAs, and unless otherwise specified, STAs refers to one or more non-AP STAs. Furthermore, there are multiple links over which non-STR non-AP MLD 1 can transmit STR AP MLD, and each non-AP STA in the non-AP STAs can transmit STR AP MLD over one or more links. However, the links over which each non-AP STA can transmit do not have to match each other.

[0062] (Device configuration example) FIG. 4 is a block diagram showing an example configuration of a communication device to which the present technology is applied.

[0063] The communication device 10 is a communication device that performs wireless communication and corresponds to the communication device 10A or the communication device 10B in Fig. 3. In Fig. 4, the communication device 10 is composed of a control unit 100, a communication unit 101, and a storage unit 102. Antennas 118-1 and 118-2 are connected to the communication unit 101.

[0064] Communication unit 101 is composed of communication control unit 111, communication storage unit 112, common data processing unit 113, individual data processing units 114-1 and 114-2, signal processing units 115-1 and 115-2, wireless interface units 116-1 and 116-2, and amplifiers 117-1 and 117-2. Amplifier unit 117-1 is connected to antenna 118-1, and amplifier unit 117-2 is connected to antenna 118-2. Communication unit 101 can have the same configuration for AP MLD and non-AP MLD.

[0065] The individual data processing unit 114-1, signal processing unit 115-1, wireless interface unit 116-1, amplifier unit 117-1, and antenna 118-1 are grouped together, and the individual data processing unit 114-2, signal processing unit 115-2, wireless interface unit 116-2, amplifier unit 117-2, and antenna 118-2 are grouped together. These groups are called individual communication sets, and two or more of these groups are components of the communication device 10, with each group in the individual communication sets performing wireless communication over its respective link.

[0066] Furthermore, the individual communication set may include a storage unit. Note that a link is a wireless transmission path that allows data transmission between two communication devices, and the links used by each pair of individual communication sets may have different frequency bands. Also, the individual data processing unit 114 and the signal processing unit 115 may be configured as one pair, and two or more pairs may be connected to one wireless interface unit 116.

[0067] The communication control unit 111 controls the operation of each unit and the transmission of information between each unit. The communication control unit 111 also controls the transfer of control information and management information to be notified to other communication devices to the data processing unit.

[0068] The communication control unit 111 has individual control units 121-1 and 121-2 that control the individual communication sets, and a common control unit 122 that performs common control over the common data processing unit 113 and the individual communication sets.

[0069] The individual control unit 121-1 transmits information indicating the period for receiving the data unit in its own individual communication set or the end of reception of the data unit (e.g., PHY-RXEND.indication) to another individual control unit 121-2 based on control information included in the received data unit (e.g., LENGTH or information to which the present technology is applied). This information may be transmitted via the common control unit 122. The individual control unit 121-2 has the same configuration as the individual control unit 121-1. In the communication unit 101 to which the present technology is applied, the signal reception period can be controlled between the individual communication sets or the individual control units while receiving signals from multiple links. Note that the information disclosed in Document 2 can be used for LENGTH and PHY-RXEND.indication.

[0070] The communication storage unit 112 is composed of a memory, a buffer, and the like, and stores information used by the communication control unit 111. The communication storage unit 112 also stores data to be transmitted and received data.

[0071] The data processing unit is made up of the common data processing unit 113, the individual data processing unit 114-1, and the individual data processing unit 114-2.

[0072] At the time of transmission, the common data processing unit 113 performs sequence management of the data stored in the communication storage unit 112 and the control information and management information received from the communication control unit 111, performs encryption processing etc. to generate data units, and allocates them to the individual data processing units 114-1 and 114-2. At the time of reception, the common data processing unit 113 performs decryption processing and reordering processing of the data units.

[0073] During transmission, the individual data processing unit 114-1 performs channel access based on carrier sense, adds a MAC (Media Access Control) header and an error detection code to the data to be transmitted, and performs concatenation of multiple data units. During reception, the individual data processing unit 114-1 performs concatenation release of the MAC header of the received data unit, analysis and error detection, and retransmission request operations. The individual data processing unit 114-2 is configured in the same way as the individual data processing unit 114-1, so a description thereof will be omitted.

[0074] The operations of the common data processing unit 113 and the individual data processing units 114-1 and 114-2 are not limited to those described above, and for example, one data processing unit may perform the operation of the other data processing unit.

[0075] During transmission, signal processing unit 115-1 performs encoding, interleaving, modulation, etc. on a data unit, adds a physical header, and generates a symbol stream. During reception, signal processing unit 115-1 analyzes the physical header, and performs demodulation, deinterleaving, decoding, etc. on the symbol stream to generate a data unit. Signal processing unit 115-1 estimates complex channel characteristics and performs spatial separation processing as necessary. Signal processing unit 115-2 has the same configuration as signal processing unit 115-1, so its description will be omitted.

[0076] During transmission, radio interface unit 116-1 performs digital-to-analog signal conversion, filtering, up-conversion, and phase control on the symbol stream to generate a transmission signal. During reception, radio interface unit 116-1 performs down-conversion, filtering, and analog-to-digital signal conversion on the received signal to generate a symbol stream. Radio interface unit 116-2 has the same configuration as radio interface unit 116-1, and therefore its description will be omitted.

[0077] Amplification unit 117-1 amplifies a signal input from wireless interface unit 116-1 or antenna 118-1. A part of amplification unit 117-1 may be a component outside communication unit 101. Alternatively, a part of amplification unit 117-1 may be included in wireless interface unit 116-1. Amplification unit 117-2 has the same configuration as amplification unit 117-1, and therefore a description thereof will be omitted.

[0078] The control unit 100 controls the communication unit 101 and the communication control unit 111. The control unit 100 may also perform part of the operations of the communication control unit 111. The control unit 100 and the communication control unit 111 may be configured as a single block.

[0079] The storage unit 102 is configured from a memory or the like, and holds information used by the control unit 100 and the communication unit 101. The storage unit 102 may also perform part of the operations of the communication storage unit 112. The storage unit 102 and the communication storage unit 112 may be configured as a single block.

[0080] 4, the wireless interface unit 116, the amplifier unit 117, and the antenna 118 may be one group, and two or more groups may be components of the communication device 10. The communication unit 101 may be realized by one or more LSIs. The common data processing unit 113 is also referred to as an upper MAC or a higher MAC, and the individual data processing unit 114 is also referred to as a lower MAC. The group of the individual data processing unit 114 and the signal processing unit 115 is also referred to as an AP entity or a non-AP entity. The communication control unit 111 is also referred to as an MLD management entity.

[0081] (Example of overall sequence) FIG. 5 is a diagram showing an example of an overall sequence showing signal exchange between devices along a time axis.

[0082] In Fig. 5, there are one STR AP MLD, one non-STR non-AP MLD, and one or more STAs (STAs), similar to the configuration example in Fig. 3. Also, in Fig. 5, the first link (Link 1) is the basic link, and the second link (Link 2) is the support link.

[0083] First, the STR AP MLD and the non-STR non-AP MLD notify each other of information indicating the capabilities of each terminal, and exchange information indicating the capabilities of their own terminals (S1: Capabilities Exchange).

[0084] After the backoff on the first link has expired, the STR AP MLD sends an RTS frame to the non-STR non-AP MLD using the first link (S2:RTS(Link 1)). The non-STR non-AP MLD that received the RTS frame sends a CTS frame to the STR AP MLD using the first link (S2:CTS(Link 1)). Note that if the backoff on the second link has expired, the non-STR non-AP MLD may send a CTS-A frame to STAs using the second link (S2:optional:CTS-A(Link 2)).

[0085] Upon receiving the CTS frame, the STR AP MLD uses the first link to send a Support Link CTS Trigger frame to the non-STR non-AP MLD, notifying it of a request for a transmission opportunity on the second link (S3: Support Link CTS Trigger (Link 1)).

[0086] Upon receiving the Support Link CTS Trigger frame, the non-STR non-AP MLD transmits a CTS-A frame to the STR AP MLD and STAs over the second link, acquiring a transmission opportunity over the second link (S4: CTS-A (Link 2)). In addition, the non-STR non-AP MLD transmits a Support Link CTS-A frame to the STR AP MLD over the first link (S5: Support Link CTS-A (Link 1)).

[0087] After receiving a Support Link CTS-A frame from the non-STR non-AP MLD, the STR AP MLD transmits data to the non-STR non-AP MLD (S6: DL Transmission). The non-STR non-AP MLD sends an Ack using the first link as a reception acknowledgement response to the data transmitted from the STR AP MLD (S7: Ack (Link 1)). The non-STR non-AP MLD also sends a frame containing transmission trigger information (hereinafter referred to as an Ack + Trigger frame) using the second link (S7: Ack + Trigger (Link 2)).

[0088] Thereafter, data transmission continues from the STR AP MLD to the non-STR non-AP MLD (S8: DL Transmission), and an Ack is sent as a reception acknowledgment response notification from the non-STR non-AP MLD to the STR AP MLD (S9: Ack).

[0089] As mentioned above, in DL (Downlink) Transmission, transmission on another link occurs while transmission on the first link is in progress. Figure 6 shows an example of transmission in DL Transmission. Figure 6 shows an example in which there are two links, the first link (Link 1) and the second link (Link 2), and transmission on the second link occurs after transmission on the first link has started.

[0090] The STR AP MLD transmits a data unit (PPDU) using the first link. The PPDU contains control information, including information indicating the length of the PPDU, in a preamble at the beginning of the PPDU. The preamble is followed by an MPDU (MAC Protocol Data Unit), which is data.

[0091] Due to the constraints of the non-STR non-AP MLD that serves as the receiving terminal, the transmission end time and reception end time of each PPDU are aligned. However, these end times only need to be within a predetermined time range, and an error within a range of, for example, 16 μs is acceptable.

[0092] Returning to FIG. 5, the STR AP MLD notifies the non-STR non-AP MLD and STAs of the release of the transmission right acquired on the first link by transmitting a CF-End (Contention Free) frame (S10: CF-End (Link 1)).

[0093] 5 mainly shows the transmission sequence between the STR AP MLD and non-STR non-AP MLD, but does not show the sequence of transmission from the STAs, except for Capabilities Exchange (S1). This is because it shows an example in which the STR AP MLD or non-STR non-AP MLD obtains the transmission right before the STAs and performs each transmission. Although not shown, transmission of data units from the STAs or transmission of data units to the STAs may occur. For example, immediately after Capabilities Exchange (S1), transmission may occur between the STR AP MLD and some STAs, and then DL Transmission (S6) may be performed.

[0094] 5 shows a case where Capabilities Exchange (S1) is performed from the STR AP MLD to the non-STR non-AP MLD, but it may also be transmitted simultaneously to the non-STR non-AP MLD and STAs. For example, this can be performed using a beacon signal that the STR AP MLD periodically transmits to multiple surrounding terminals. While FIG. 5 shows a case where Capabilities Exchange (S1) is performed between the STR AP MLD and the non-STR non-AP MLD, and then between the STR AP MLD and STAs, the order in which they are performed is not limited, and they may also be reversed.

[0095] 5 may be omitted as necessary, and the order may differ from that shown in the figure. For example, if it is determined that an ACK is not required depending on the type of data being transmitted, there is no need to exchange an ACK. Also, for example, an ACK exchanged immediately after a DL Transmission (S6, S8) or a UL Transmission does not necessarily have to be performed at this timing, and may be performed together immediately before a CF-End (S10).

[0096] Below, as details of each sequence in FIG. 5, examples of transmission and configuration of frames notified in each sequence will be described.

[0097] (S1:Capabilities Exchange) In the Capabilities Exchange, STR AP MLD and non-STR non-AP MLD communicate information about their own capabilities to each other. Capabilities here refer to, but are not limited to, whether a terminal can perform STR transmission and the number of links it can transmit simultaneously.

[0098] Capability Exchange may be implemented by being included in, for example, a beacon signal periodically transmitted by each terminal, or in information notification (Association) for establishing a connection between terminals after a beacon signal is transmitted.

[0099] FIG. 7 is a diagram showing an example of the structure of a frame notified in Capabilities Exchange.

[0100] The frame notified in the Capabilities Exchange is composed of Frame Control, RA (Receiving STA address), TA (Transmitting STA address), and Multi-Link element. The components of the frame are not limited to these, and other components may also be included.

[0101] The Frame Control contains information indicating that the frame is a frame notified by Capabilities Exchange. The RA and TA contain information indicating the source terminal and destination terminal, respectively.

[0102] For example, the RA and TA may indicate a MAC (Media Access Control) address specific to the terminal. In particular, when the source terminal or destination terminal is an MLD, multiple MAC addresses may be assigned to one MLD.

[0103] Specifically, they may be assigned to each individual communication set within one MLD or each link used by one MLD. In other words, RA and TA do not indicate only the MLD, but are information for identifying not only the MLD that notifies the frame but also the individual communication set or link of the MLD. Note that, as will be described later, they may also be identified together with the MLD MAC Address in the Multi-Link element.

[0104] The Multi-Link element includes information indicating the links that can be used as links for the terminal itself that transmits the frame, the links that can be used simultaneously as STRs, and the links that can be used as NSTRs.

[0105] The Multi-Link element includes fields for Element ID, Length, Element ID Extension, Multi-Link Control, MLD MAC Address, and Per-STA Profile.

[0106] The Element ID contains information indicating that the element is a Multi-Link element. When storing this information, the Element ID Extension may be used together with the Element ID. The Length contains information indicating the bit length of the Multi-Link element.

[0107] The Multi-Link Control includes information indicating whether there is a subsequent MLD MAC Address and whether downlink transmission can be performed even if the transmission right is acquired in the second link. The MLD MAC Address includes identification information assigned individually to the MLD terminal, regardless of the link or individual communication set. The Per-STA Profile includes information about each link or each individual communication set.

[0108] The Multi-Link Control contains subfields MLD MAC Address Present and Rapid Non-STR TXOP.

[0109] MLD MAC Address Present contains information indicating the presence of an MLD MAC Address. Rapid Non-STR TXOP contains the following information (a) and (b).

[0110] (a) Information indicating that if the terminal transmitting the frame is an STR AP MLD, it can transmit a data unit in accordance with a control signal notified from the non-STR non-AP MLD even when the non-STR non-AP MLD has acquired the transmission right on the second link. (b) Information indicating that, if the terminal transmitting the frame is a non-STR non-AP MLD, even if it acquires the transmission right on the second link, it can transmit a control signal to induce the STR AP MLD to transmit a data unit, and that it can receive a data unit transmitted from the STR AP MLD after transmitting the control signal.

[0111] The Per-STA Profile includes subfields for Sub element ID, Length, and Per-STA Control.

[0112] The Sub-element ID contains information indicating that the subfield is a Per-STA Profile. The Length contains information indicating the bit length of the Per-STA Profile. The Per-STA Control contains information about the link or individual communication set indicated by the Per-STA Profile. Note that there may be multiple Per-STA Profiles, each indicating information about a different link or individual communication set.

[0113] The Per-STA Control further includes subfields for Link ID, Bandwidth, Non-STR Pair Link ID, and STR Pair Link ID.

[0114] The Link ID includes information indicating the target link or individual communication set. The Bandwidth includes information indicating the frequency band in which the link or individual communication set indicated by the Link ID can transmit.

[0115] The Non-STR Pair Link ID includes information indicating a link or individual communication set that operates as a non-STR MLD when used simultaneously with the link or individual communication set indicated by the Link ID.

[0116] For example, if the Link ID contains information indicating the first link (Link 1) and the Non-STR Pair Link ID contains information indicating the second link (Link 2), it can be interpreted that the terminal notifying the frame must transmit in a manner that satisfies the operational constraints of non-STR MLD when receiving (or transmitting) using the first and second links simultaneously.

[0117] The STR Pair Link ID includes information indicating a link or individual communication set that operates as a non-STR MLD when used simultaneously with the link or individual communication set indicated by the Link ID.

[0118] In the Capabilities Exchange, the AP MLD and non-STR non-AP MLD notify each other of their capabilities, and then secure the transmission right and transmit the data unit. Figure 8 shows the frames transmitted by each terminal in the series of processes (S2 to S10) after the Capabilities Exchange in chronological order.

[0119] In Fig. 8, similar to the configuration example in Fig. 3, there is one STR AP MLD, one non-STR non-AP MLD1, and multiple STAs, non-AP STA2 and non-AP STA3. In Fig. 8, the two upper time series represent frames transmitted by the STR AP MLD on the upper side of the time axis for the first link (Link 1) and the second link (Link 2), and frames transmitted by the non-STR non-AP MLD 1 on the lower side of the time axis. The first link (Link 1) is the basic link, and the second link (Link 2) is the support link. Also, in Fig. 8, the two lower time series represent the usage of the first link by non-AP STA2 and the second link by non-AP STA3.

[0120] A series of processes (S2 to S10) after Capabilities Exchange will be described below with reference to the timeline in FIG. 8 as needed.

[0121] (S2:RTS / CTS(Link l),CTS-A(Link 2)) The STR AP MLD whose backoff has expired in the first link transmits an RTS frame to the non-STR non-AP MLD 1. The RTS frame includes information indicating a request to acquire the right to transmit for period D1 (FIG. 8) in communication with the non-STR non-AP MLD 1.

[0122] The non-STR non-AP MLD1, which received the RTS frame on the first link, transmits a CTS frame to the STR AP MLD using the first link. The CTS frame contains information indicating that the RTS frame from the STR AP MLD has been notified of the RTS frame and that the MLD has been granted (approved) the right to transmit.

[0123] At this time, if the backoff of non-STR non-AP MLD1 has expired in the second link, non-STR non-AP MLD1 may transmit a CTS-A frame to surrounding terminals. The CTS-A frame transmitted in the second link includes information indicating that the transmission right for period D2' (FIG. 8) has been acquired.

[0124] Among the terminals that receive the above RTS and CTS frames, terminals other than those that receive STR AP MLD or non-STR non-AP MLD1 refrain from transmitting during the period indicated by each frame. For example, terminals that receive the RTS and CTS frames transmitted over the first link refrain from transmitting during period D1 (or the period until time t1) in Figure 8.

[0125] Here, the RTS frame and CTS frame correspond to the RTS frame and CTS frame disclosed in the above-mentioned document 2. In document 2, the period during which transmission is refrained within a terminal other than the STR AP MLD or non-STR non-AP MLD1 is called NAV (Network Allocation Vector), and as shown in Fig. 8, for example, non-AP STA2 connected to the STR AP MLD via the first link sets this period as its NAV.

[0126] (S3: Support Link CTS Trigger(Link l)) The STR AP MLD that receives the CTS frame transmitted from the non-STR non-AP MLD1 over the first link transmits a Support Link CTS Trigger frame to the non-STR non-AP MLD1 over the first link.

[0127] FIG. 9 is a diagram illustrating an example of the configuration of a Support Link CTS Trigger frame.

[0128] The Support Link CTS Trigger frame is composed of Frame Control, RA, TA, HT (High Throughput) Control, and FCS (Frame Check Sequence). The components of the frame are not limited to these, and other components may be included.

[0129] The Frame Control includes information indicating that the frame is a Support Link CTS Trigger frame.

[0130] As will be described later, the information included in the Frame Control field may include information indicating that the frame is a Support Link CTS Trigger frame when combined with the information included in the EHT variant ID and Control ID in the HT Control. That is, a terminal receiving the frame can interpret the frame as a Support Link CTS Trigger frame based on the information included in the Frame Control, EHT variant ID, and Control ID.

[0131] The RA and TA contain information indicating the source terminal and destination terminal, respectively. For example, the RA and TA may indicate a MAC address specific to the terminal. Furthermore, particularly when the source terminal or destination terminal is an MLD, the RA and TA may be a MAC address defined for the individual communication set of the terminal or for each link used by the terminal, and may also be a MAC address identified as an MLD.

[0132] The HT Control contains information about the link that transmits the CTS frame to the receiving terminal and the transmission right acquired by the CTS frame. The FCS contains parity information for the receiving terminal to perform error correction on the information contained in the frame.

[0133] The HT Control contains fields such as EHT variant ID, Control ID, Support Link ID, Support Link Req TXOP, and Support Link DL / UL.

[0134] The EHT variant ID and Control ID include information in Frame Control that indicates that the frame is a Support Link CTS Trigger frame. The Support Link ID includes information that indicates the link for which the destination terminal is requested to transmit a CTS-A frame.

[0135] The Support Link Req TXOP includes information indicating the transmission right (or transmission period, for example, period D2 in FIG. 8) to be acquired with the requested CTS-A frame.

[0136] The Support Link DL / UL includes information indicating permission to transmit a data unit (PPDU) to the destination terminal (non-STR non-AP MLD1) over the first and second links. That is, after transmitting the frame, the non-STR non-AP MLD1 transmits a Support Link CTS-A frame over the first link, and the Support Link DL / UL includes information indicating permission to transmit a data unit (PPDU) over the first and second links to the non-STR non-AP MLD1 in the transmission immediately following that.

[0137] 9 shows a configuration in which the Support Link ID and Support Link Req TXOP fields are included in the HT Control, but they do not necessarily have to be included in the HT Control and may be included in another field. Also, the EHT variant ID and Control ID may be defined as one field.

[0138] (S4:CTS-A(Link 2),S5:Support Link CTS-A(Link l)) Upon receiving the Support Link CTS Trigger, the non-STR non-AP MLD1 transmits a Support Link CTS-A frame using the first link, and also transmits a CTS-A frame using the second link.

[0139] FIG. 10 is a diagram illustrating an example of the configuration of a Support Link CTS-A frame.

[0140] The Support Link CTS-A frame is composed of Frame Control, RA, TA, HT Control, and FCS. The components of the frame are not limited to these, and other components may be included.

[0141] The Frame Control field contains information indicating that the frame is a Support Link CTS-A frame. As will be described later, the information contained in the Frame Control field may be combined with the information contained in the EHT variant ID and Control ID in the HT Control field to contain information indicating that the frame is a Support Link CTS-A frame. In other words, a terminal receiving the frame can interpret the frame as a Support Link CTS-A frame based on the information contained in the Frame Control field, EHT variant ID, and Control ID.

[0142] The RA and TA contain information indicating the source terminal and destination terminal, respectively. For example, the RA and TA may indicate a MAC address specific to the terminal. Furthermore, particularly when the source terminal or destination terminal is an MLD, the RA and TA may be a MAC address defined for the individual communication set of the terminal or for each link used by the terminal, and may also be a MAC address identified as an MLD.

[0143] The HT Control contains information about the link that transmits the CTS frame to the receiving terminal and the transmission right acquired by the CTS frame. The FCS contains parity information for the receiving terminal to perform error correction on the information contained in the frame.

[0144] The HT Control contains fields for EHT variant ID, Control ID, Support Link ID, Support Link TXOP, and Support Link More PPDU.

[0145] The EHT variant ID and Control ID include information in Frame Control that indicates that the frame is a Support Link CTS-A frame. The Support Link ID includes information that indicates the link over which the terminal transmitting the frame transmitted the CTS-A frame.

[0146] The Support Link TXOP includes information indicating the transmission right (or transmission period, for example, period D2 in FIG. 8) that the terminal transmitting the frame has acquired by using the CTS-A frame.

[0147] The Support Link More PPDU contains information indicating whether the terminal transmitting the frame will transmit a data unit (PPDU) immediately after transmitting the frame on the link indicated by the Support Link ID in the frame.

[0148] Note that the information indicating the transmission right contained in the Support Link TXOP does not necessarily have to match the Support Link Req TXOP in the Support Link CTS Trigger notified immediately before, and similarly, the information indicating the link contained in the Support Link ID does not necessarily have to match the Support Link ID in the Support Link CTS Trigger notified immediately before.

[0149] Furthermore, the information contained in the Support Link More PPDU can include information indicating that a data unit will be transmitted immediately after transmitting the frame only when the Support Link DL / UL in the Support Link CTS Trigger notified from the STR AP MLD, which is the destination terminal of the frame, includes information indicating that data transmission is permitted to the non-STR non-AP MLD1, and only when the non-STR non-AP MLD1 holds at least a data unit to transmit to the STR AP MLD.

[0150] Also, in Figure 10, a configuration is shown in which the fields Support Link ID and Support Link TXOP are included in the HT Control, but in essence they do not need to be included in the HT Control and may be included in another field, and the EHT variant ID and Control ID may be defined as a single field.

[0151] Next, an example of the structure of the CTS-A frame will be described. The structure of the CTS-A frame transmitted using the second link can be the same as the CTS frame disclosed in Document 2. However, the CTS-A frame includes information indicating that the transmission right will be acquired for the link indicated by the Support Link ID in the most recently notified Support Link CTS Trigger during the period indicated by the Support Link Req TXOP in the most recently notified Support Link CTS Trigger.

[0152] 8 shows a case where the "link indicated by the Support Link ID in the most recently notified Support Link CTS Trigger" is the "second link (Link 2)" and the "period indicated by the Support Link Req TXOP in the most recently notified Support Link CTS Trigger" is "period D2." In this case, among the terminals that received the CTS-A frame on the second link, terminals excluding the STR AP MLD set this period D2 as their NAV and refrain from transmission.

[0153] Note that Literature 2 mentions that information indicating TXOP extension may be included in any frame. While Fig. 8 shows a case where the CTS-A frame acquires the transmission right for period D2, the TXOP may be extended by transmitting a frame including information indicating TXOP extension on the second link after the transmission of the CTS-A frame. For example, the CTS-A frame may acquire a TXOP for a period shorter than period D2, but a frame transmitted after the CTS-A frame may ultimately acquire the transmission right for period D2.

[0154] Furthermore, if the STR AP MLD that notified the Support Link CTS Trigger frame fails to correctly receive a CTS-A frame from the non-STR non-AP MLD1 on the second link within a specific time from the end of transmission of the Support Link CTS Trigger frame, it may notify the Support Link CTS Trigger frame again.

[0155] At this time, the non-STR non-AP MLD1 may again transmit a Support Link CTS-A frame using the first link and a CTS-A frame using the second link in the same manner as described above, in accordance with the Support Link CTS Trigger frame notified again. However, the transmission right (or transmission period) acquired by the CTS-A frame may indicate the same time as the end time of the transmission right (or transmission period) notified in the first CTS-A frame.

[0156] (S6:DL Transmission,S7:Ack(Link l), Ack + Trigger(Link 2)) After the non-STR non-AP MLD1 sends a Support Link CTS-A frame over the first link, either DL (Downlink) Transmission or UL (Uplink) Transmission is performed. DL Transmission is the transmission of data units from the STR AP MLD to the non-STR non-AP MLD1. UL Transmission is the transmission of data units from the non-STR non-AP MLD1 to the STR AP MLD.

[0157] At this time, agreement on performing uplink (UL) or downlink (DL) between the STR AP MLD and the non-STR non-AP MLD1 can be formed, for example, as follows.

[0158] Downlink (DL) is performed when the Support Link More PPDU in the Support Link CTS-A frame notified on the first link by the non-STR non-AP MLD immediately before contains information indicating that "a data unit will be transmitted after the Support Link More PPDU frame."

[0159] An uplink (UL) is implemented when the Support Link More PPDU in the Support Link CTS-A frame notified on the first link by the non-STR non-AP MLD immediately before contains information indicating that "no data units will be transmitted after the Support Link More PPDU frame."

[0160] In addition, when uplink (UL) is implemented, non-STR non-AP MLD1 allows the sequence numbers assigned to MPDUs transmitted on each link to be consecutive, and the set of arbitrary sequence numbers assigned to MPDUs transmitted on the first link can be smaller than the set of arbitrary sequence numbers transmitted on other links.

[0161] This is because if the STR AP MLD fails to receive the CTS-A frame correctly on the second link, it may also fail to receive it correctly on the uplink (UL). In this case, the retransmission request notifies the sequence number of the MPDU that was not received correctly. However, if consecutive numbers are not assigned on the first link, the field length indicating the sequence number to be retransmitted will be too long.

[0162] 8 shows a case where the downlink (DL) is still being performed, but in this case the entity that has acquired the transmission right in the second link is not the STR AP MLD but the non-STR AP MLD 1. In this case, the non-STR non-AP MLD 1 that has acquired the transmission right in the second link needs to notify the STR AP MLD of an Ack + Trigger frame that includes control information indicating a transmission trigger in the second link before transmitting PPDU#2-1.

[0163] FIG. 11 is a diagram illustrating an example of the configuration of an Ack+Trigger frame.

[0164] The Ack + Trigger frame is composed of Frame Control, RA, TA, Multi Link ID, Support Link Grant, and FCS. The components of the frame are not limited to these, and other components may be included.

[0165] The Frame Control includes information indicating that the frame is an Ack+Trigger frame.

[0166] The RA and TA contain information indicating the source terminal and destination terminal, respectively. For example, the RA and TA may indicate a MAC address specific to the terminal. Furthermore, particularly when the source terminal or destination terminal is an MLD, the RA and TA may be a MAC address defined for the individual communication set of the terminal or for each link used by the terminal, and may also be a MAC address identified as an MLD.

[0167] The Multi Link ID includes information indicating to the destination terminal of the frame the link to be used for transmission after receiving the frame.

[0168] The Support Link Grant includes information indicating that the destination terminal of the frame is permitted to transmit after receiving the frame.

[0169] The FCS includes parity information for performing error correction on the information included in the frame at the receiving terminal.

[0170] In Fig. 8, the STR AP MLD, which is a terminal that has been notified of the Ack + Trigger frame as the desired destination, may start transmission using any link indicated by the Multi Link ID. Also, as shown in Fig. 8, the Ack + Trigger frame can be transmitted together with an acknowledgment (Ack) frame.

[0171] In addition, when uplink (UL) is performed consecutively or when downlink (DL) and uplink (UL) are performed alternately, a similar frame, i.e., an Ack + Trigger frame, is exchanged immediately before transmission. However, when uplink (UL) is performed after downlink (DL) or when downlink (DL) is performed after uplink (UL), it cannot be transmitted together with the acknowledgement (Ack) frame, so for example, the following notification can be performed:

[0172] Fig. 12 is a diagram showing, in time series, frames transmitted by each terminal when uplink transmission is performed first and then downlink transmission is performed. In the time series of Fig. 12, as in the time series of Fig. 8, there is one STR AP MLD, one non-STR non-AP MLD1, and multiple STAs, non-AP STA2 and non-AP STA3.

[0173] In Figure 12, if uplink transmission is performed first and then downlink transmission is performed, the Ack + Trigger frame shown in Figure 11 must be transmitted from non-STR non-AP MLD before transmitting PPDU#2-2, and in this case, the control information contained in the frame can be included in PPDU#1-2 and notified.

[0174] Similarly, when uplink transmission is performed following downlink transmission, the control information included in the Ack+Trigger frame can be included in the PPDU transmitted in the downlink transmission.

[0175] FIG. 13 is a diagram showing an example of the structure of a frame included in a data unit when DL Transmission is performed.

[0176] The frame included in the data unit when DL Transmission is performed is composed of Frame Control, RA, TA, Support Link ID, Support Link CTS-A Error, and Support Link Backoff Count. The components of the frame are not limited to these, and other components may be included.

[0177] The Frame Control contains information indicating that the frame is included in a data unit. The RA and TA contain information indicating the source terminal and destination terminal, respectively.

[0178] For example, RA and TA may indicate MAC addresses specific to the terminals. In particular, when the source terminal or destination terminal is an MLD, RA and TA may be MAC addresses defined for the individual communication set of the terminal or for each link used by the terminal, and may also be MAC addresses identified as MLDs.

[0179] The Support Link ID includes information indicating the link used in the CTS-A frame transmitted immediately before from the non-STR non-AP MLD1.

[0180] The Support Link CTS-A Error contains information indicating the link that was unable to correctly receive the CTS-A frame among the links indicated in the Support Link ID.

[0181] The Support Link Backoff Count includes information indicating the remaining transmission waiting time due to backoff in the terminal transmitting the frame for each link indicated in the Support Link ID.

[0182] The Support Link Backoff Count may indicate the value of a backoff counter present in the terminal transmitting the frame. In this case, the backoff counter may indicate a value for each link.

[0183] Furthermore, the Support Link ID, Support Link CTS-A Error, and Support Link Backoff Count may not be included in the data unit, but may be included in a Control Frame or Management Frame, as disclosed in Reference 2. However, if they are included in such a frame, the information indicated in Frame Control and information in other fields indicates that the notified frame contains the Support Link ID, Support Link CTS-A Error, and Support Link Backoff Count.

[0184] The FCS includes parity information for performing error correction on the information contained in the frame at the receiving terminal.

[0185] Fig. 14 is a time series diagram showing frames transmitted by each terminal when the CTS-A frame is not correctly received by the STR AP MLD on the second link. In the time series of Fig. 14, there is one STR AP MLD, one non-STR non-AP MLD1, and multiple STAs, non-AP STA2 and non-AP STA3, just like the time series of Fig. 8. In Fig. 14, DL Transmission is being performed.

[0186] In Figure 14, a CTS-A frame is transmitted from non-STR non-AP MLD1 using the second link, but for a certain period of time, due to interference from terminals around the STR AP MLD, the STR AP MLD is unable to correctly receive and demodulate the CTS-A frame ("BUSY" in the figure).

[0187] In this case, since the transmission right has already been acquired by the STR AP MLD on the first link, the STR AP MLD relies on the Support Link CTS-A frame notified by non-STR non-AP MLD1 on the first link to notify that the CTS-A frame was not correctly received on the second link by a frame transmitted on the first link. The information used at this time is the information included in the Support Link ID and Support Link CTS-A Error shown in Figure 13.

[0188] If the interference is due to a WLAN signal, the STR AP MLD can estimate the duration of the interference and the time when its backoff expires and transmission can start on the second link after the interference has ended. Information indicating the start time or information for estimating the start time is included in the Support Link Backoff count shown in FIG. 13.

[0189] 14, while non-STR non-AP MLD1 is receiving PPDU#1-1 in the first link, it cannot transmit any signal due to NSTR restrictions. Also, after receiving PPDU#1-1, the STR AP MLD becomes ready to transmit and starts transmitting.

[0190] At this time, even though non-STR non-AP MLD1 has acquired the transmission right in the second link, STR AP MLD1 starts transmission without a control signal (trigger) inducing transmission from non-STR non-AP MLD1. This is because, as shown in Fig. 14, PPDU#2-1 is received by non-STR non-AP MLD1 in the first link, and during this reception period non-STR non-AP MLD1 cannot transmit any signals due to NSTR restrictions.

[0191] However, for example, if the Support Link Backoff count (FIG. 13) indicates (or includes information that can be estimated) that the time when STR AP MLD transmission can start on the second link is after the completion of reception of PPDU#1-1, the non-STR non-AP MLD1 can transmit a frame that includes, for example, the following information. That is, first, it can include information indicating that transmission for the STR AP MLD will be triggered on the second link using the second link at the same time as the reception acknowledgment (Ack) on the first link, and second, it can include information indicating that the transmission right acquired on the second link will be released. However, a frame including the information shown in the latter paragraph can be implemented using the CF-End frame disclosed in Document 2.

[0192] Fig. 15 is a time series diagram showing frames transmitted by each terminal when the transmission right acquired in the second link is released. In the time series of Fig. 15, as in the time series of Fig. 8, there is one STR AP MLD, one non-STR non-AP MLD1, and multiple STAs, non-AP STA2 and non-AP STA3.

[0193] In FIG. 15, it is shown that a CF-End frame is used as a frame containing the information shown in the latter part above, i.e., information indicating that the transmission right acquired in the second link is to be released.

[0194] At this time, at the same time as the CF-End frame is transmitted over the second link, the non-STR non-AP MLD1 notifies the STR AP MLD of information indicating that the non-STR non-AP MLD will use the first link to release the transmission right it acquired over the second link.

[0195] FIG. 16 is a diagram showing an example of the structure of a Support Link End frame that is notified when the transmission right acquired on the link is released.

[0196] The Support Link End frame is composed of Frame Control, RA, TA, Support Link ID, TXOP End Request, and FCS. The components of the frame are not limited to these, and other components may be included.

[0197] The Frame Control contains information indicating that the frame contains Support Link ID and TXOP End Request. The RA and TA contain information indicating the source terminal and destination terminal, respectively.

[0198] The Support Link ID includes information indicating a link other than the link through which the frame is transmitted that will release the transmission right acquired by the terminal transmitting the frame.

[0199] The TXOP End Request includes information indicating that the terminal transmitting the frame will release the transmission right acquired on the link indicated by the Support Link ID.

[0200] The FCS includes parity information for performing error correction on the information contained in the frame at the receiving terminal.

[0201] Here, the above-mentioned operations of the non-STR non-AP MLD and STR AP MLD will be explained with reference to a systematically summarized flowchart. In Figures 17 and 18, as in the configuration example of Figure 3, it is assumed that there are one STR AP MLD, one non-STR non-AP MLD, and one or more STAs (STAs). Also in Figures 17 and 18, the first link (Link 1) is the basic link, and the second link (Link 2) is the support link.

[0202] (Example of processing non-STR non-AP MLD) First, the flow of processing performed in non-STR non-AP MLD will be described with reference to the flowchart in FIG.

[0203] The processing performed by the non-STR non-AP MLD starts when an RTS frame is notified from the STR AP MLD over the first link, and the non-STR non-AP MLD receives the RTS frame sent from the STR AP MLD over the first link (S101).

[0204] The non-STR non-AP MLD that has received the RTS frame determines whether the backoff counter (or backoff) of the second link has expired and the channel in the second link is in an idle state (unused state) (S102).

[0205] If it is determined that the channel in the second link is idle ("Yes" in S102), the non-STR non-AP MLD generates a CTS frame and a CTS-A frame, and simultaneously transmits the CTS frame on the first link and the CTS-A frame on the second link to the STR AP MLD (S103).

[0206] On the other hand, if it is determined that the channel in the second link is not idle ("No" in S102), the non-STR non-AP MLD generates a CTS frame and transmits the CTS frame to the STR AP MLD over the first link (S106). In this case, the transmission of a CTS-A frame over the second link is not performed.

[0207] Thereafter, in the first link, a Support Link CTS Trigger frame is notified from the STR AP MLD, and the non-STR non-AP MLD receives the Support Link CTS Trigger frame transmitted from the STR AP MLD (S104, S107).

[0208] At this time, if a CTS-A frame has been transmitted in advance on the second link (S103, S104), the non-STR non-AP MLD has acquired the transmission right on the second link. To extend this transmission right, the non-STR non-AP MLD transmits a CTS-A frame on the second link to the STR AP MLD (S105).

[0209] Furthermore, the non-STR non-AP MLD generates a Support Link CTS-A frame and transmits it to the STR AP MLD via the first link at the same time as the CTS-A frame (S105). This notifies the STR AP MLD that the non-STR non-AP MLD has acquired the transmission right via the second link and the period of the acquired transmission right.

[0210] On the other hand, if a CTS-A frame has not been transmitted in advance on the second link (S106, S107), the non-STR non-AP MLD has not acquired the right to transmit on the second link. Therefore, the non-STR non-AP MLD again determines whether the backoff counter (or backoff) for the second link has expired and the channel on the second link is in an idle state (S108).

[0211] If it is determined that the channel in the second link is idle ("Yes" in S108), the non-STR non-AP MLD generates a Support Link CTS-A frame and a CTS-A frame, and simultaneously transmits the Support Link CTS-A frame on the first link and the CTS-A frame on the second link to the STR AP MLD (S109).

[0212] On the other hand, if it is determined that the channel in the second link is not idle ("No" in S108), the non-STR non-AP MLD generates a Support Link CTS-A frame and transmits it to the STR AP MLD over the first link (S110). In this case, the CTS-A frame is not transmitted over the second link.

[0213] When the process of any one of steps S105, S109, or S110 is completed, the series of processes performed in non-STR non-AP MLD is completed.

[0214] (STR AP MLD processing example) Next, the flow of processing performed in the STR AP MLD will be described with reference to the flowchart of FIG.

[0215] The process performed by the STR AP MLD starts when the non-STR non-AP MLD notifies a Support Link CTS-A frame over the first link and a CTS-A frame over the second link. In other words, the process in step S109 in Fig. 17 is premised on the assumption that the non-STR non-AP MLD simultaneously transmits a Support Link CTS-A frame over the first link and a CTS-A frame over the second link.

[0216] The STR AP MLD determines whether or not the CTS-A frame transmitted from the non-STR non-AP MLD via the second link has been correctly received (S121).

[0217] If it is determined that the CTS-A frame transmitted from the non-STR non-AP MLD over the second link has been correctly received ("Yes" in S121), the STR AP MLD analyzes the Support Link CTS-A frame and the CTS-A frame to determine whether or not a PPDU is to be transmitted subsequently (S122).

[0218] If it is determined that a subsequent PPDU will be transmitted ("Yes" in S122), the STR AP MLD performs a receiving operation for the PPDU transmitted from the non-STR non-AP MLD on the first link and the second link (S123).

[0219] Furthermore, if it is determined that no subsequent PPDU will be transmitted ("No" in S122), the STR AP MLD performs an operation of transmitting a PPDU to the non-STR non-AP MLD in the first link and the second link (S124).

[0220] Regarding the above-mentioned "Support Link CTS-A frame and a PPDU are transmitted following the CTS-A frame" ("Yes" in S122), this interpretation can be made in the STR AP MLD when at least one of the following (c) and (d) is satisfied from the non-STR non-AP MLD to the STR AP MLD:

[0221] (c) When the RDG / More PPDU subfield in the Support Link CTS-A frame notified on the first link contains information indicating that a PPDU will be transmitted following the Support Link CTS-A frame. (d) When the RDG / More PPDU subfield in the CTS-A frame notified on the second link does not contain information indicating permission to transmit a PPDU to the destination STR AP MLD after receiving the CTS-A frame.

[0222] Furthermore, with regard to the above-mentioned "No PPDU is transmitted following the Support Link CTS-A frame and the CTS-A frame" ("No" in S122), such an interpretation can be made in the STR AP MLD when at least one of the following (e) and (f) is satisfied from the non-STR non-AP MLD to the STR AP MLD.

[0223] (e) If the RDG / More PPDU subfield in the Support Link CTS-A frame notified on the first link does not contain information indicating that a PPDU will be transmitted following the Support Link CTS-A frame. (f) When the RDG / More PPDU subfield in the CTS-A frame notified on the second link contains information indicating permission to transmit a PPDU to the destination STR AP MLD after receiving the CTS-A frame.

[0224] That is, in order to notify a Support Link CTS-A frame and information indicating that a PPDU will be transmitted following the CTS-A frame, the non-STR non-AP MLD generates and notifies information that satisfies at least one of the above (c) and (d). On the other hand, in order to notify a Support Link CTS-A frame and information indicating that a PPDU will not be transmitted following the CTS-A frame, the non-STR non-AP MLD generates and notifies information that satisfies at least one of the above (e) and (f).

[0225] On the other hand, if it is determined that the CTS-A frame transmitted from the non-STR non-AP MLD cannot be received correctly on the second link ("No" in S121), the STR AP MLD analyzes and determines whether the Support Link CTS-A frame indicates that a PPDU will be transmitted subsequently (S125).

[0226] If it is determined that a PPDU will be subsequently transmitted ("Yes" in S125), the STR AP MLD performs a receiving operation for the PPDU transmitted from the non-STR non-AP MLD at least in the first link (S126).

[0227] Furthermore, if it is determined that no subsequent PPDU will be transmitted ("No" in S125), the STR AP MLD transmits a PPDU to the non-STR no-AP MLD via the first and second links (S127). Furthermore, the STR AP MLD can transmit a PPDU including information indicating that the CTS-A frame was not received correctly to the non-STR non-AP MLD via the first link (S127).

[0228] If the CTS-A frame notified from the non-STR non-AP MLD on the second link cannot be correctly received ("No" in S121), it may be that the CTS-A frame cannot be correctly received due to an interfering signal from another wireless communication terminal near the STR AP MLD that receives the CTS-A frame. The period of the interfering signal may extend into the reception period of the PPDU notified from the non-STR non-AP MLD on the second link, and the PPDU notified from the non-STR non-AP MLD on the second link cannot be correctly received and demodulated.

[0229] In this case, the common control unit 122 (FIG. 4) can control the MPDUs transmitted over the first and second links from the non-STR non-AP MLD so that the sequence numbers of the MPDUs transmitted over the first and second links are assigned as follows, for example: That is, the set of arbitrary sequence numbers assigned to MPDUs transmitted over the first link can be controlled so as to be smaller than the arbitrary sequence numbers transmitted over other links.

[0230] When the process of any one of steps S123, S124, S126, or S127 is completed, the series of processes performed in the STR AP MLD is completed.

[0231] As described above, in a communication device to which the present technology is applied (e.g., communication device 10A that is STR AP MLD), a control unit (e.g., control unit 100 or communication control unit 111) transmits a first frame (e.g., an RTS frame) including a request to acquire the transmission right for the first link using a first link (e.g., a basic link) to another communication device (e.g., communication device 10B that is non-STR non-AP MLD), and when a second frame (e.g., a CTS frame) including permission to acquire the transmission right for the first link that is transmitted from the other communication device using the first link is received, a third frame (e.g., a Support Link CTS Trigger frame) including information that induces the other communication device to acquire the transmission right for a second link (e.g., a support link) different from the first link is generated, and control is performed to transmit the third frame to the other communication device using the first link.

[0232] Furthermore, in a communication device to which the present technology is applied (for example, communication device 10B that is non-STR non-AP MLD), when a control unit (for example, control unit 100 or communication control unit 111) receives a first frame (for example, an RTS frame) that includes a request to acquire the transmission right for the first link and is transmitted from another communication device (for example, communication device 10A that is STR AP MLD) using a first link (for example, a basic link), the control unit transmits a second frame (for example, a CTS frame) that includes permission to acquire the transmission right for the first link to the other communication device using the first link, and when a third frame (for example, a Support Link CTS Trigger frame) that includes information that triggers the acquisition of the transmission right for a second link (for example, a support link) different from the first link and is transmitted from the other communication device using the first link, the control unit generates a fifth frame (for example, a Support Link CTS-A frame) that includes information that indicates the transmission right acquired on the second link, and transmits the fifth frame to the other communication device using the first link.

[0233] Furthermore, in a communication device to which the present technology is applied (for example, communication device 10B that is non-STR non-AP MLD), when a control unit (for example, control unit 100 or communication control unit 111) receives a third frame (for example, a Support Link CTS Trigger frame) from another communication device using a first link (for example, a basic link), if the second link (for example, a support link) is unused, the control unit generates a fourth frame (for example, a CTS-A frame) including information indicating the transmission right acquired on the second link, transmits a fifth frame (for example, a Support Link CTS-A frame) using the first link, and transmits the fourth frame to the other communication device using the second link.

[0234] This improves the chances of acquiring transmission rights for multiple links. For example, a communication device (e.g., the communication device 10B, which is a non-STR non-AP MLD) can acquire the transmission right for a second link (e.g., a support link).

[0235] <2. Modifications>

[0236] (Other configuration examples) As described above, communication device 10A can be configured as a STR AP MLD, and communication device 10B can be configured as a non-STR non-AP MLD. However, communication device 10A or communication device 10B may be configured as part of a device (component) that configures the STR AP MLD or non-STR non-AP MLD (for example, a wireless communication module, a wireless chip, or the like).

[0237] Furthermore, communication device 10B configured as a non-STR non-AP MLD and communication devices 10C and 10D configured as non-AP STAs can be configured as electronic devices with wireless communication functions, such as smartphones, tablet terminals, game devices, mobile phones, personal computers, digital cameras, television sets, wearable terminals, speaker devices, etc. Furthermore, communication devices 10B to 10D may be electronic devices that are only capable of transmitting data, such as controllers that transmit command data in response to user operations, or electronic devices that are only capable of receiving data, such as display devices that receive and display video data.

[0238] The above-described series of processes of the communication device 10 can be executed by hardware or software. When the series of processes are executed by software, a program constituting the software is installed in the communication device 10.

[0239] Furthermore, the embodiments of the present technology are not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present technology. For example, in the above description, each embodiment is described using a sequence diagram, a frame configuration diagram, and a flowchart, but these embodiments are not necessarily limited to the illustrated configurations and may be used appropriately depending on the situation. Furthermore, the effects described in this specification are merely examples and are not limited thereto, and other effects may also be obtained. Note that the above-described "CTS-A frame" may be read as a "CTS-to-self frame" containing similar information.

[0240] The present technology can be configured as follows.

[0241] (1) Frames are exchanged with other communication devices via wireless communication using multiple links, transmitting a first frame including a request to acquire a transmission right for the first link to the other communication device using the first link; when receiving a second frame transmitted from the other communication device using the first link and including permission to acquire a transmission right for the first link, generating a third frame including information for inducing the other communication device to acquire a transmission right for a second link different from the first link; transmitting the third frame to the other communication device using the first link; Equipped with a control unit that controls Communication equipment. (2) The third frame includes information indicating a transmission right or a transmission period to be acquired by a fourth frame requesting transmission from the other communication device. The communication device according to (1) above. (3) The third frame includes information indicating the second link requesting transmission of the fourth frame. The communication device according to (2) above. (4) The third frame is transmitted temporally after a fifth frame transmitted from the other communication device using the first link temporally after the third frame, and includes information indicating permission to transmit data units on the first link and the second link to the other communication device. The communication device according to (2) or (3). (5) When the control unit receives the fifth frame, which is transmitted from the other communication device using the first link and includes information indicating the transmission right acquired on the second link, the control unit receives or transmits a data unit to or from the other communication device using at least the first link, based on information included in the fifth frame that indicates whether or not to transmit a data unit following the fifth frame. The communication device according to (4) above. (6) When the control unit normally receives the fourth frame transmitted from the other communication device using the second link and including information indicating a transmission right acquired on the second link, the control unit receives or transmits a data unit to or from the other communication device using the first link and the second link based on information indicating permission to transmit a data unit after receiving the fourth frame, which is included in the fourth frame. The communication device according to (5) above. (7) When the fourth frame is not received normally, the control unit uses at least the first link to receive or transmit a data unit to or from the other communication device. The communication device according to (6) above. (8) The control unit transmits, to the other communication device, a data unit including information indicating that the fourth frame could not be normally received using the first link. The communication device according to (7) above. (9) The access point is configured to support transmission using multiple links simultaneously and to be capable of transmitting and receiving for each link, The other communication device includes a user terminal capable of transmitting or receiving between multiple links. The communication device according to any one of (1) to (8). (10) Frames are exchanged with other communication devices via wireless communication using multiple links, when receiving a first frame including a request to acquire a transmission right for the first link, which is transmitted from the other communication device using a first link, transmitting a second frame including permission to acquire a transmission right for the first link to the other communication device using the first link; when receiving a third frame including information inducing acquisition of a transmission right for a second link different from the first link, the third frame being transmitted from the other communication device using the first link, generating a fifth frame including information indicating the transmission right acquired for the second link; transmitting the fifth frame to the other communication device using the first link; Equipped with a control unit that controls Communication equipment. (11) The control unit generating a fourth frame including information indicating a transmission right acquired through the second link when the third frame is received from the other communication device using the first link and the second link is unused; Transmitting the fifth frame using the first link and transmitting the fourth frame to the other communication device using the second link. The communication device according to (10) above. (12) The fifth frame includes information indicating the transmission right or transmission period acquired by the fourth frame. The communication device according to (11) above. (13) The fifth frame includes information indicating the second link that transmitted the fourth frame. The communication device according to (11) or (12). (14) The fifth frame includes information indicating whether a data unit is to be transmitted using the second link following the fifth frame. The communication device according to any one of (11) to (13). (15) The fourth frame includes information indicating that the transmission right for the second link will be acquired during a period corresponding to information indicating permission to transmit data units on the first link and the second link, which is included in the third frame. The communication device according to any one of (11) to (14). (16) the control unit receives the first frame from the other communication device using the first link, and when the second link is in use, receives the third frame from the other communication device using the first link, and when the second link is in use, transmits the fifth frame to the other communication device using the first link. The communication device according to any one of (11) to (15). (17) the control unit receives the first frame from the other communication device using the first link, and when the second link is in use, receives the third frame from the other communication device using the first link, and when the second link is unused, transmits the fifth frame using the first link and transmits the fourth frame to the other communication device using the second link. The communication device according to (16) above. (18) When a data unit is transmitted to the other communication device using the first link and the second link after the fifth frame is transmitted to the other communication device using the first link, sequence numbers assigned to a plurality of sub-data units constituting the data unit transmitted on each link are consecutive. The communication device according to any one of (10) to (17). (19) A set of arbitrary sequence numbers assigned to sub-data units transmitted on the first link is smaller than any set of sequence numbers assigned to sub-data units transmitted on the second link. The communication device according to (18). (20) a user terminal configured to transmit or receive data between a plurality of links; The other communication device includes an access point that supports transmission using multiple links simultaneously and can perform transmission and reception for each link. The communication device according to any one of (10) to (19). [Explanation of symbols]

[0242] 10, 10A, 10B communication device, 100 control unit, 101 communication unit, 102 memory unit, 111 communication control unit, 112 communication memory unit, 113 common data processing unit, 114-1, 114-2 individual data processing unit, 115-1, 115-2 signal processing unit, 116-1, 116-2 wireless interface unit, 117-1, 117-2 amplifier unit, 118-1, 118-2 antenna

Claims

1. Frames are exchanged with other communication devices via wireless communication using multiple links, transmitting a first frame to the other communication device using a first link, the first frame including a request to acquire a transmission right for the first link; when receiving a second frame transmitted from the other communication device using the first link and including permission to acquire a transmission right for the first link, generating a third frame including information for inducing the other communication device to acquire a transmission right for a second link different from the first link; transmitting the third frame to the other communication device using the first link; Equipped with a control unit that controls Communication equipment.

2. The third frame includes information indicating a transmission right or a transmission period to be acquired by a fourth frame requesting transmission from the other communication device. The communication device according to claim 1 .

3. The third frame includes information indicating the second link requesting transmission of the fourth frame. The communication device according to claim 2 .

4. The third frame is transmitted temporally after a fifth frame transmitted from the other communication device using the first link temporally after the third frame, and includes information indicating permission to transmit data units on the first link and the second link to the other communication device. The communication device according to claim 3 .

5. When the control unit receives the fifth frame including information indicating the transmission right acquired on the second link, which is transmitted from the other communication device using the first link, the control unit receives or transmits a data unit to or from the other communication device using at least the first link based on information indicating whether or not to transmit a data unit subsequent to the fifth frame, which is included in the fifth frame. The communication device according to claim 4.

6. When the control unit normally receives the fourth frame transmitted from the other communication device using the second link and including information indicating a transmission right acquired through the second link, the control unit receives or transmits a data unit to or from the other communication device using the first link and the second link based on information indicating permission to transmit a data unit after receiving the fourth frame, which is included in the fourth frame. The communication device according to claim 5 .

7. When the fourth frame is not received normally, the control unit uses at least the first link to receive or transmit a data unit to or from the other communication device. The communication device according to claim 6.

8. The control unit transmits, to the other communication device, a data unit including information indicating that the fourth frame was not successfully received using the first link. The communication device according to claim 7.

9. The access point is configured to support transmission using multiple links simultaneously and to be capable of transmitting and receiving for each link, The other communication device includes a user terminal capable of transmitting or receiving between multiple links. The communication device according to claim 1 .

10. Frames are exchanged with other communication devices via wireless communication using multiple links, when receiving a first frame including a request to acquire a transmission right for the first link, which is transmitted from the other communication device using a first link, transmitting a second frame including permission to acquire a transmission right for the first link to the other communication device using the first link; when receiving a third frame including information inducing acquisition of a transmission right for a second link different from the first link, the third frame being transmitted from the other communication device using the first link, generating a fifth frame including information indicating the transmission right acquired for the second link; transmitting the fifth frame to the other communication device using the first link; Equipped with a control unit that controls Communication equipment.

11. The control unit generating a fourth frame including information indicating a transmission right acquired through the second link when the third frame is received from the other communication device using the first link and the second link is unused; Transmitting the fifth frame using the first link and transmitting the fourth frame to the other communication device using the second link. The communication device according to claim 10.

12. The fifth frame includes information indicating the transmission right or transmission period acquired by the fourth frame. The communication device according to claim 11.

13. The fifth frame includes information indicating the second link that transmitted the fourth frame. The communication device of claim 12.

14. The fifth frame includes information indicating whether a data unit is to be transmitted using the second link following the fifth frame.

14. The communication device of claim 13.

15. The fourth frame includes information indicating that the transmission right for the second link will be acquired during a period corresponding to information indicating permission to transmit data units on the first link and the second link, which is included in the third frame. The communication device according to claim 11.

16. The control unit receives the first frame from the other communication device using the first link, and when the second link is in use, receives the third frame from the other communication device using the first link, and when the second link is in use, transmits the fifth frame to the other communication device using the first link. The communication device according to claim 11.

17. the control unit receives the first frame from the other communication device using the first link, and when the second link is in use, receives the third frame from the other communication device using the first link, and when the second link is unused, transmits the fifth frame using the first link and transmits the fourth frame to the other communication device using the second link.

17. The communication device of claim 16.

18. When a data unit is transmitted to the other communication device using the first link and the second link after the fifth frame is transmitted to the other communication device using the first link, sequence numbers assigned to a plurality of sub-data units constituting the data unit transmitted on each link are consecutive. The communication device according to claim 10.

19. A set of arbitrary sequence numbers assigned to sub-data units transmitted on the first link is smaller than any set of sequence numbers assigned to sub-data units transmitted on the second link.

20. The communication device of claim 18.

20. a user terminal configured to transmit or receive data between a plurality of links; The other communication device includes an access point that supports transmission using multiple links simultaneously and can perform transmission and reception for each link. The communication device according to claim 10.

Images