First wireless communication device, second wireless communication device, and wireless communication system

Abstract

To provide a communication device that improves transmission efficiency by using a plurality of links.SOLUTION: A communication device that performs wireless communication by using a plurality of links provides information about changes of a transmission period in a first link which are associated with performing of transmission by further using a second link during the transmission period using the first link. The communication device provides, in the first link, information indicating whether acquisition of transmission right is being attempted in the second link, and provides, in the second link, information indicating whether information on at least a transmission period described in a frame being transmitted in the first link has been changed and the information about the changes of the transmission period in the first link.SELECTED DRAWING: Figure 8

Description

[Technical Field]

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

[0002] In a wireless LAN (Local Area Network), in the unlicensed band, an access point (AP or BS) and a user terminal (STA or UE (User Equipment)) autonomously acquire transmission rights within a single basic service set (BSS) and communicate within the BSS.

[0003] In recent years, the amount of data handled in high-definition video transmissions such as AR (Augmented Reality), VR (Virtual Reality), and 4K / 8K has become extremely large, requiring further transmission capacity in wireless transmissions, and therefore there is a demand for an expansion of the frequency bandwidth used for transmission.

[0004] However, there is a problem that the unlicensed frequency band is limited and it is difficult to secure a wide frequency bandwidth. For this reason, the IEEE 802.11 TG (Task Group) be is studying a transmission method that effectively uses a wider frequency bandwidth by simultaneously using multiple frequency bands such as the 5 GHz band and the 6 GHz band. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Yongho Seok,et al.,"Proposed Draft Text for MLO Multi-Link Channel Access: PPDU End Time Alignment," IEEE802.11-20 / 1271r8,Sep.9,2020 [Non-patent document 2] Zhou Lan,et al., "MLO a-synchronize and synchronize operation discussions," IEEE 802.11-20 / 291r1 Jan.20,2020 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a communication device and a communication method for performing wireless communication using multiple frequency bands. [Means for solving the problem]

[0007] The present disclosure has been made in consideration of the above-described problems, and a first aspect thereof provides a communication device that performs wireless communication using a plurality of links, notifying information regarding a change in the transmission period of the first link due to transmission using a second link during the transmission period using the first link; It is a communication device.

[0008] A communication device according to a first aspect notifies a transmission partner of the information via the second link. Specifically, the communication device according to the first aspect describes, for each transmission unit constituting a data frame transmitted via the first link, information indicating whether or not acquisition of a transmission right on the second link is being attempted, and also describes, for each transmission unit constituting a data frame transmitted via the second link, information indicating whether or not information relating to at least the transmission period described in the frame transmitted via the first link has changed, and the information relating to the change in the transmission period on the first link.

[0009] A communication device according to a first aspect can perform another transmission using at least one of the first link and the second link during an original transmission period on the first link.

[0010] Alternatively, the communication device according to the first aspect can notify another terminal of the release of the second link within the original transmission period of the first link.

[0011] A second aspect of the present disclosure is a communication method for performing wireless communication using a plurality of links, comprising: initiating transmission on a first link; During the transmission period using the first link, further starting transmission using a second link; notifying information about a change in a transmission period in the first link due to transmission using the second link; It is a communication method having the following.

[0012] A third aspect of the present disclosure is a communication device that performs wireless communication using a plurality of links, receiving information about a change in the transmission period of the first link due to transmission using the second link when data is received via the second link while data is being received via the first link; It is a communication device.

[0013] A communication device according to a second aspect controls communication operations in the first link based on the information received in the second link.

[0014] Specifically, a communication device according to a second aspect performs a receiving process on the second link when it receives information on the first link indicating that a communication partner is attempting to acquire the transmission right for the second link, and receives information on the second link indicating whether or not at least information on the transmission period described in a frame transmitted on the first link has changed, and the information on the change in the transmission period on the first link, and controls communication operations on the first link.

[0015] A communication device according to a second aspect includes a MAC layer processor that performs processing in the MAC layer for each link, and a common data processor that performs data processing common to all links, and the MAC layer processor of the second link notifies the MAC layer processor of the first link of the information received on the second link via the common data processor.

[0016] A fourth aspect of the present disclosure is a communication method for performing wireless communication using a plurality of links, comprising: receiving data on a first link; performing a receiving process on the second link when receiving information on the first link indicating that a communication partner is attempting to acquire a transmission right on the second link; receiving, when receiving data via the second link, information relating to a change in a transmission period of the first link due to transmission using the second link; controlling communication operations in the first link based on the information received in the second link; It is a communication method having the following. [Effects of the Invention]

[0017] According to the present disclosure, it is possible to provide a communication device and a communication method that improve transmission efficiency by using multiple links.

[0018] It should be noted that the effects described in this specification are merely examples, and the effects brought about by the present disclosure are not limited to these. Furthermore, the present disclosure may also bring about additional effects in addition to the effects described above.

[0019] Further objects, features, and advantages of the present disclosure will become apparent from the following detailed description based on the embodiments and accompanying drawings. [Brief explanation of the drawings]

[0020] [Figure 1]FIG. 1 is a diagram showing an example of an operation for transmitting data from an STR AP MLD to a non-STR non-AP MLD. [Figure 2] FIG. 2 is a diagram showing an example of an operation in which an STR MLD receives data from another MLD using multiple links. [Figure 3] FIG. 3 is a diagram showing an example of the configuration of a wireless network system to which the present disclosure is applied. [Figure 4] FIG. 4 is a diagram showing an example of the configuration of the communication device 400. As shown in FIG. [Figure 5] FIG. 5 is a diagram showing an example of a communication sequence (first embodiment) performed in a wireless network system. [Figure 6] FIG. 6 is a diagram showing an example of a transmission operation in DL Transmission. [Figure 7] FIG. 7 is a diagram showing an example of the structure of a frame notified in Capabilities Exchange. [Figure 8] FIG. 8 is a diagram showing a specific example of the operation of DL Transmission and UL Transmission. [Figure 9] FIG. 9 is a diagram showing an example of the configuration of a PPDU. [Figure 10] FIG. 10 is a diagram showing an example of the operation within the communication unit 410 in non-STR non-AP MLD1. [Figure 11] FIG. 11 is a flowchart showing the operation performed by a common entity in a non-STR non-AP MLD. [Figure 12] FIG. 12 is a diagram showing an example of a communication sequence (second embodiment) performed in a wireless network system. [Figure 13] FIG. 13 is a diagram showing a specific example of the operation of DL Transmission and UL Transmission. [Figure 14] FIG. 14 is a diagram showing an example of the structure of a frame notified by Enhanced CF-End. [Figure 15]FIG. 15 is a diagram showing an example of the operation within communication unit 410 in non-STR non-AP MLD1. [Figure 16] FIG. 16 is a diagram showing an example of a communication sequence (third embodiment) performed in a wireless network system. [Figure 17] FIG. 17 is a diagram showing an example of the structure of a frame notified in Capabilities Exchange. [Figure 18] FIG. 18 is a diagram showing an example of the structure of a frame notified in Capabilities Exchange. [Figure 19] FIG. 19 is a diagram showing a specific example of the operation of DL Transmission and UL Transmission. [Figure 20] FIG. 20 is a diagram showing an example of the configuration of a PPDU. [Figure 21] FIG. 21 is a diagram showing an example of the operation within the communication unit 410 in STR non-AP MLD1. DETAILED DESCRIPTION OF THE INVENTION

[0021] The present disclosure will be described below in the following order with reference to the drawings.

[0022] A. Current status of multi-link transmission B. Summary of this Disclosure C. System configuration example D. Equipment configuration example E. First Example F. Second Example G. Third Example H. Summary

[0023] A. Current status of multi-link transmission A-1. Introduction of multi-link In order to secure a wider frequency band within a limited frequency band, methods of transmitting using multiple frequency bands simultaneously are being considered (as mentioned above). Here, a frequency band is also called a "link." A terminal that can transmit using multiple frequency bands, i.e., multiple links simultaneously, is also called an MLD (Multi-Link Device). An AP that is an MLD is called an "AP MLD (Access Point Multi-Link Device)," and an STA that is an MLD is called a "non-AP MLD."

[0024] "Transmitting using multiple links simultaneously" does not mean transmitting by controlling multiple links independently, but rather means separately controlling the communication operations between multiple links to improve communication quality. For example, transmission using multiple links simultaneously can be achieved by the following operations. However, a link refers to a wireless transmission path that can transmit data between two communication devices, and the frequency bands of each link may be different.

[0025] (1) Transmitting synchronized signals across multiple links. (2) Performing uplink transmission from a STA to an AP on one link and downlink transmission from the AP to the STA on a different link.

[0026] A-2. Introduction of STR and NSTR in multi-link transmission 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 transmission rights for each frequency. For this reason, it is possible that a single STA may transmit to an AP, for example, uplink in the 5 GHz band and downlink in the 6 GHz band, or may transmit only uplink or only downlink over both links. In other words, it is possible to use multiple links to simultaneously transmit and receive on each link (Simultaneous Transmit and Receive (STR)), or to perform either transmission or reception between multiple links (NSTR: non-STR).

[0027] When non-AP MLD performs STR, the signal it transmits leaks into the signal it receives, resulting in increased self-interference and a deterioration in communication quality (see Non-Patent Document 1). This problem is caused, for example, by the following:

[0028] (1) Proximity between links (frequency bands). (2) When the STA-MLD uses a different antenna for each link, the correlation between the STA-MLD antennas and the characteristics of the bandpass filters attached to the antennas.

[0029] Non-AP MLD that causes the above problem is defined as a terminal that does not implement STR, and is called "non-STR non-AP MLD" or "STA is NSTR limited." However, because this depends not only on the terminal profile but also on the links used simultaneously, the same terminal may be controlled to operate as a non-STR MLD on a specific link pair and as an STR MLD on another link pair. Hereinafter, non-STR non-AP MLD is defined as "a non-AP MLD that operates as a non-STR on at least the link pair of interest."

[0030] A-3. Issues with non-STR terminals: Necessity of controlling the end time of received data When a non-STR non-AP MLD receives signals from a single terminal simultaneously over multiple links, the end-of-reception times of the received signals on each link must be synchronized. 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. In other words, if the end-of-reception times of each received signal are not synchronized, the non-STR non-AP MLD will send an Ack on one link while independently receiving a signal on another link, which could result in an unintentional STR (i.e., sending an Ack and receiving a signal simultaneously).

[0031] The above signal is a data unit with a certain time width, and is called a PPDU (Physical Layer Convergence Protocol (PLCP) Protocol Data Unit) (see Non-Patent Document 2). Non-Patent Document 1 also states that the above specified period is set to approximately 16 microseconds, although the value depends on the implementation of the device, and that when signals are transmitted using multiple links with the same non-STR non-AP MLD as the destination, the difference between the transmission end times of the transmitted signals on each link must be within 8 microseconds.

[0032] A-4. Overview of current proposals and methods for multi-link transmission: Synchronous and asynchronous transmission Non-Patent Document 2 defines the following two types of transmissions over multiple links for non-AP MLD: In particular, for transmissions over non-STR non-AP MLD, the reception termination times (or transmission end times of transmission signals) of each link must be synchronized.

[0033] (1) Synchronized Transmission (Sync.Tx) - Data is sent across different links with the same start time. (2) Asynchronous Transmission (Async.Tx) - Data is sent across different links without aligning the start time of transmission.

[0034] A-5. Problems with synchronous transmission and advantages of asynchronous transmission The conditions for performing synchronous transmission will be explained mainly based on the description in Non-Patent Document 1.

[0035] In a wireless LAN, typically, each terminal cannot acquire the transmission right until a random waiting time (backoff) has expired. The condition for synchronous transmission described in Non-Patent Document 1 is that synchronous transmission is performed only 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 to ensure fairness for each link, since the backoff is determined by the degree of transmission congestion on each link.

[0036] However, if there is a bias in the degree of congestion of transmissions on each link, the backoff applied to each link will be different. Therefore, when backoffs on all links are completed, synchronous transmission will inevitably be performed in the most congested environment. Therefore, while waiting for the completion of backoffs on all links before performing synchronous transmission, other terminals may acquire the transmission right on some links, reducing the probability of performing synchronous transmission.

[0037] Therefore, by adopting asynchronous transmission, it is possible to acquire the transmission right from a link whose backoff has expired, and the probability of performing multi-link transmission from AP MLD to non-STR non-AP MLD can be improved, and asynchronous transmission contributes to improving the throughput of the entire system.

[0038] A-6.Currently under discussion: Asynchronous transmission methods Non-Patent Document 2 mentions that asynchronous transmission is performed using the following methods (A) to (C). However, the link that first acquires the transmission right is called "Link 1" (or Basic Link), and the link that later acquires the transmission right is called "Link 2" (or Support Link). Also, the data to be transmitted is called PPDU.

[0039] (A) Each link transmits a PPDU asynchronously after the backoff expires. (B) On link 1, a PPDU is transmitted after obtaining a TXOP (Transmission Opportunity) by notifying an RTS (Request to send) frame and a CTS (Clear to send) frame, but on link 2, a PPDU is transmitted without sending an RTS or CTS frame. (C) An RTS frame and a CTS frame are notified on each link, and a PPDU is transmitted after acquiring a TXOP for each link.

[0040] In particular, in the case of transmission for non-STR non-AP MLD, the transmission end times of PPDUs transmitted on each link must be synchronized.

[0041] However, in asynchronous transmission, there may occur cases where the end time t1 of the receiving operation on link 1 is later than the end time t2 of the receiving operation on link 2. In this case, the transmission time of the Ack frame at the receiving terminal becomes an issue.

[0042] Figure 1 shows an example of an operation for transmitting data (PPDU) from an STR AP MLD to a non-STR non-AP MLD. In the figure, the horizontal axis represents time. However, the upper part of Figure 1 shows an example of an operation for transmission using only link 1, and the lower part of Figure 1 shows an example of an operation for transmission using links 1 and 2. The PPDU also contains a preamble and multiple MPDUs (Media Access Control Protocol Data Units).

[0043] As shown in the upper part of Figure 1, when transmission is performed using only link 1, the STR AP MLD transmits the PPDU to the non-STR non-AP MLD after the backoff expires. After demodulating the PPDU, the non-STR non-AP MLD returns an Ack via link 1. As shown in the figure, the transmission period is T1 and the transmission end time is t1.

[0044] On the other hand, when transmission is performed using link 1 and link 2 as shown in the lower part of Figure 1, the STR AP MLD transmits a PPDU for each link to the non-STR non-AP MLD after the backoff expires for each link. The non-STR non-AP MLD demodulates the PPDU on link 1 and link 2, and then returns an Ack on link 1 and link 2. As shown in the figure, the transmission period is T2, and the transmission end time is t2. There is a difference in transmission period ΔT (T1 - T2) between transmission using only link 1 and transmission using link 1 and link 2.

[0045] In a wireless LAN, information indicating the length of a PPDU (i.e., the time length of data) is included in the preamble, which is the beginning of a PPDU. The terminal determines whether reception of a received signal has ended when the PHY (Physical) layer in the terminal notifies the MAC (Media Access Control) layer of the PHY-RXEND.indication, which indicates the end of reception. Furthermore, the PHY-RXEND.indication is not notified to the MAC layer until after the reception time estimated based on the PPDU length included in the preamble of the received signal.

[0046] When STR AP MLD acquires the transmission right on Link 2 while transmitting data on Link 1, it transmits data that would normally be transmitted using only Link 1 on Link 2, thereby shortening the data transmission period by ΔT from T1 to T2, as shown in the bottom of Figure 1. However, due to the restriction on the notification timing of the PHY-RXEND.indication mentioned above, the MAC layer of Link 1 behaves as a receiver until the transmission period before the shortening, that is, until time t1. This is essentially because the MAC layers of Link 1 and Link 2 do not define the information to notify that the transmission period has been shortened, nor the interface for notifying this information.

[0047] For this reason, in asynchronous transmission, the end time of the receiving operation on link 1 is delayed relative to the end time of the receiving operation on link 2. As a result, in non-STR non-AP MLD, Ack can only be sent on link 1 after time t1, not time t2, and data cannot be transmitted during the shortened transmission period (ΔT in Figure 1) and must wait. In other words, in asynchronous transmission, although a certain transmission period can be shortened, the Ack transmission time is delayed, resulting in a problem of deterioration in transmission efficiency as a system.

[0048] Furthermore, although not shown in Figure 1, even if it were possible for the non-STR non-AP MLD to send an Ack at time t2, if another terminal other than the non-STR non-AP MLD in Figure 1 is present on link 1, that terminal will refrain from transmitting until time t1, when the transmission period T1 notified in the original PPDU ends. As a result, transmission will not be possible from the time the non-STR non-AP MLD finishes sending an Ack until time t1, resulting in a problem of a deterioration in the transmission efficiency of the system.

[0049] The same problem as above also exists when an STR MLD receives data from another MLD using multiple links. Figure 2 shows an example of operation when transmitting data (PPDU) from an STR AP MLD to an STR non-AP MLD. In the figure, the horizontal axis represents the time axis. However, the upper part of Figure 2 shows an example of operation when transmission is performed using only link 1, while the lower part of Figure 2 shows an example of operation when transmission is performed using links 1 and 2. When transmission is performed using links 1 and 2, unlike when reception is performed by a non-STR MLD as shown in the lower part of Figure 1, the reception end times of each link do not need to be the same. This is due to the removal of the constraints of non-STR MLD.

[0050] As shown in the lower part of Figure 2, if STR AP MLD has an opportunity to transmit on link 2 while transmitting on link 1, the transmission period on link 1 will be shortened by ΔT (T1 - T2) compared to when transmission is performed using only link 1, as shown in the upper part of Figure 2. However, in STR non-AP MLD, unless information indicating the shortened transmission period ΔT on link 1 is not notified from the MAC layer of link 2 to the MAC layer of link 1, reception will continue on link 1 for the transmission period T1 before the shortening, in accordance with the information indicating the PPDU length included in the PPDU received on link 1.

[0051] For this reason, even with STR non-AP MLD, Ack can only be sent on link 1 after time t1, not time t2, and data cannot be transmitted during the shortened transmission period (ΔT in Figure 2) and must wait. In other words, although the transmission period can be shortened, the Ack transmission time is delayed, resulting in a similar problem of a deterioration in transmission efficiency as a system.

[0052] B. Summary of this Disclosure In order to solve the problem described in Section A above, this disclosure proposes the following operations (1) to (3) when STR AP MLD is transmitting to non-AP MLD using link 1 and then transmitting using link 2.

[0053] (1) The STR AP MLD notifies the non-AP MLD of the shortened transmission period (period ΔT in Figures 1 and 2) on link 1 by using link 2. (Here, non-AP MLD includes non-STR non-AP MLD and STR non-AP MLD.) (2) When a non-AP MLD receives asynchronously transmitted signals on multiple links, within the non-AP MLD, the MAC layer of link 2 notifies the MAC layer of link 1 of the shortened transmission period ΔT on link 1. (3) During the shortened transmission period ΔT, transmission from non-AP MLD to STR AP MLD is performed at least on link 1.

[0054] C. System configuration example 3 shows an example configuration of a wireless network system to which the present disclosure is applied. In the wireless network system shown, one access point (AP MLD) is connected to one non-STR non-AP MLD1, as well as non-AP STA2 and non-AP STA3, which are terminals that are not access points. However, the non-AP STA may be any of a non-STR non-AP MLD, an STR non-AP MLD, and a non-AP STA that is not an MLD.

[0055] In the example shown in Figure 3, two non-AP STAs (i.e., non-AP STA 2 and non-AP STA 3) are connected to the AP MLD, but the number of non-AP STAs is not particularly limited. There may be no non-AP STAs other than non-STR non-AP MLD 1, or there may be one or three or more non-AP STAs other than non-STR non-AP MLD 1. Furthermore, an STR non-AP MLD may be connected to the AP MLD instead of the non-STR non-AP MLD.

[0056] In the following explanation, the set of non-AP STAs other than non-STR non-AP MLD1 is defined as non-AP STAs, and unless otherwise specified, non-AP STAs refers to one or more non-AP STAs. Also, unless otherwise specified, AP MLD is assumed to be STR AP MLD.

[0057] The links in the wireless network system shown in Figure 3 will now be explained. There are multiple links over which non-STR non-AP MLD1 can transmit with AP MLD, and each non-AP STA among the non-AP STAs can transmit with AP MLD over one or more links. Note that the links over which each non-AP STA can transmit do not have to match each other. The link that first acquires the right to transmit AP MLD to non-STR non-AP MLD is called "Link 1" (or Basic Link), and the link that later acquires the right to transmit is called "Link 2" (or Support Link).

[0058] D. Equipment configuration example Fig. 4 shows an example configuration of a communication device 400 that operates as an MLD (AP MLD or non-AP MLD) capable of multi-link transmission using link 1 and link 2 in the wireless network system shown in Fig. 3. The communication device 400 shown in the figure includes a communication unit 410, a control unit 420, a storage unit 430, and an antenna 440. The communication unit 410 includes a communication control unit 411, a communication storage unit 412, a common data processing unit 413, an individual data processing unit 414, a signal processing unit 415, a wireless interface unit 416, and an amplifier 417.

[0059] Each of the individual data processing unit 414, signal processing unit 415, wireless interface unit 416, amplifier unit 417, and antenna 440 in the communication unit 410 is provided for each link, and each unit for link 1 has the suffix "-1" added to its name, and each unit for link 2 has the suffix "-2" added to its name. However, in the following, when the explanation is common, the notations "-1" and "-2" will be omitted. Each unit will be explained below.

[0060] The amplifier 417 amplifies a signal input from the wireless interface 416 or the antenna 440. A part of the amplifier 417 may be a component outside the communication unit 410. Alternatively, a part of the amplifier 417 may be included in the wireless interface unit 414.

[0061] During transmission, the wireless interface unit 416 performs digital-to-analog signal conversion, filtering, up-conversion, and phase control on the symbol stream to generate a transmission signal, and during reception, the wireless interface unit 416 performs down-conversion, filtering, and analog-to-digital signal conversion on the received signal to generate a symbol stream.

[0062] During transmission, the signal processing unit 415 performs encoding, interleaving, modulation, etc. on the data unit, adds a physical header, and generates a symbol stream. During reception, the signal processing unit 415 analyzes the physical header, and performs demodulation, deinterleaving, decoding, etc. on the symbol stream to generate a data unit. The signal processing unit 415 also estimates complex channel characteristics and performs spatial separation processing as necessary.

[0063] The communication device 400 includes a common data processing unit 413 as a data processing unit, and an individual data processing unit 414 for each link.

[0064] During transmission, the common data processing unit 413 performs sequence management of the data stored in the communication storage unit 412 and the control information and management information received from the communication control unit 411, performs encryption processing and the like to generate data units, and allocates them to the individual data processing units 414 for each link. During reception, the common data processing unit 413 performs decryption processing and reordering processing of the data units.

[0065] During transmission, the individual data processing unit 414 performs channel access based on carrier sense, adds a MAC 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 414 performs MAC header deconcatenation processing, analysis and error detection, and retransmission request operations for the received data units.

[0066] The operations of the common data processing unit 413 and the individual data processing unit 414 are not limited to those described above, and one may perform the operation of the other.

[0067] The individual data processing unit 414, signal processing unit 415, wireless interface unit 416, amplifier unit 417, and antenna 440, each provided for a link, are grouped together (hereinafter also referred to as an "individual communication set"), and two or more individual communication sets are components of the communication device 400, with each individual communication set performing wireless communication via its respective link. Each individual communication set may also include a storage unit (not shown). A link is a wireless transmission path over which data can be transmitted between two communication devices, and the links used by each individual communication set may use different frequency bands. The individual data processing unit 414 and the signal processing unit 415 may also be grouped together, and two or more groups may be connected to one wireless interface unit 416.

[0068] The communication control unit 411 controls the operation of each unit and the transmission of information between each unit, and also controls the transfer of control information and management information to each data processing unit to be notified to other communication devices.

[0069] As shown in FIG. 4, the communication control unit 411 includes individual control units 411-1 and 411-2 that control the individual communication sets, and a common control unit 411-3 that performs common control of the common data processing unit 413 and the individual communication sets. In the present disclosure, each of the individual control units 411-1 and 411-2 has a function of transmitting information indicating the period for receiving the data unit in its own individual communication set or the end of reception of the data unit (PHY-RXEND.indication) from control information (length and duration information) included in the received data unit to another individual control unit. Each of the individual control units 411-1 and 411-2 may perform the above transmission via the common control unit 411-3. In the present disclosure, it is assumed that the signal reception period can be controlled between the individual communication sets or the individual control units while signals are being received from multiple links.

[0070] The communication storage unit 412 stores information used by the communication control unit 411. The communication storage unit 412 also stores data to be transmitted through each link and data received from each link.

[0071] The control unit 420 controls the communication unit 410 and the communication control unit 411. The control unit 420 may also perform part of the operations of the communication control unit 411. The communication control unit 411 and the control unit 420 may also be physically configured as one block.

[0072] The storage unit 430 holds information used by the control unit 420 and the communication unit 410. The storage unit 430 may also perform part of the operations of the communication storage unit 412. The storage unit 430 and the communication storage unit 412 may be physically configured as one block.

[0073] The wireless interface unit 416, the amplifier unit 417, and the antenna 440 may be one set, and two or more sets may be components of the communication device. The communication unit 410 may be realized by one or more LSIs (Large Scale Integration). The common data processing unit 413 is also referred to as an upper MAC or a higher MAC, and the individual data processing unit 414 is also referred to as a lower MAC.

[0074] The set of the individual data processing unit 414 and the signal processing unit 415 is also called an AP entity or a non-AP entity. The communication control unit 411 is also called an MLD management entity.

[0075] E. First Example Fig. 5 shows an example of a communication sequence performed in a wireless network system as a first embodiment. The vertical axis represents time. As in Fig. 3, a wireless network system is assumed in which one AP MLD, one non-STR non-AP MLD, and one or more STAs (hereinafter referred to as "STAs") exist.

[0076] The following four types of transmission are shown in the example communication sequence in Figure 5. Details of the frames notified in each transmission will be described later.

[0077] (1) Capabilities Exchange: Notification of information indicating the capabilities of each device (2) DL (Downlink) Transmission: Data transmission from AP MLD to non-STR non-AP MLD (3) UL (Uplink) Transmission: Data transmission from non-STR non-AP MLD to AP MLD (4) Ack: Acknowledgment of receipt of each data transmission in (2) and (3) above

[0078] E-1. Points to note Before describing each transmission shown in FIG. 5, a few points should be noted.

[0079] E-1-1. Points to note regarding transmission rights 5 shows the sequence of transmission between AP MLD and non-STR non-AP MLD, but does not show transmission with STAs. This is because FIG. 5 shows an example in which AP MLD or non-STR non-AP MLD acquires the transmission right before STAs and performs each transmission. Although not shown, transmission from STAs to AP MLD or transmission from AP MLD to STAs may occur. For example, DL Transmission may be performed after transmission occurs between AP MLD and some STAs immediately after Capabilities Exchange.

[0080] In DL transmission, while transmission is taking place on one link (hereinafter referred to as "Link 1"), transmission on another link occurs. Also, Ack transmission and UL transmission on the two links from non-STR non-AP MLD may be performed within the transmission right (period during which transmission is permitted) secured by AP MLD transmission on Link 1.

[0081] E-1-2. Points to note regarding DL Transmission As described above, in DL Transmission, while transmission is taking place on one link (link 1), transmission is taking place on another link (link 2).

[0082] Figure 6 shows an example of operation in which transmission is performed on link 1 and link 2 in DL transmission. The horizontal axis represents time. This figure shows an example in which transmission on link 2 occurs after transmission on link 1 starts when DL transmission is performed using two links, link 1 and link 2, between a STR AP MLD and a non-STR non-AP MLD.

[0083] The AP MLD transmits a data unit (PPDU) on link 1. The PPDU contains control information such as the PPDU length in a preamble, which is the beginning of the PPDU. The preamble is followed by the MPDU, which is the data.

[0084] Due to the constraints of the non-STR non-AP MLD that serves as the receiving terminal, the transmission end time or reception end time of each PPDU must be the same (non-AP MLD must send an Ack within a specified period on the link where reception has finished. If the reception end times are not the same, an Ack must be sent on one link while reception is in progress on the other link, which violates the non-STR constraints.) However, this end time only needs to be within a certain time range, and an error within a range of, for example, 16 microseconds is acceptable.

[0085] E-1-3. Points to note regarding transmission order 5 shows a case where Capabilities Exchange is performed from the AP MLD to the non-STR non-AP MLD, but Capabilities Exchange may be transmitted simultaneously to the non-STR non-AP MLD and STAs. As a specific example, Capabilities Exchange may be performed using a beacon signal that the AP MLD periodically transmits to multiple nearby terminals.

[0086] Although not shown in Fig. 5, Capabilities Exchange may also occur from STAs to AP MLD. As a specific example, after AP MLD transmits a beacon signal, Capabilities Exchange may be transmitted from STAs to AP MLD. Note that the order of Capabilities Exchange performed by non-STR non-AP MLD and STAs is not particularly limited.

[0087] If necessary, parts of each sequence may be omitted, and the order may not be as shown in Fig. 5. For example, if it is determined that an Ack is not necessary depending on the type of data being transmitted, an Ack may not be sent.

[0088] E-2.Capabilities Exchange AP MLD and non-STR non-AP MLD exchange information about their own capabilities (hereafter referred to as "Capabilities Exchange"). The capabilities here refer to, but are not limited to, whether the terminal can perform STR transmission and the number of links that can transmit simultaneously.

[0089] Capability Exchange may be carried out 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.

[0090] Figure 7 shows an example of the structure of a frame notified in Capabilities Exchange. The frame shown in the figure is composed of the following fields: Frame Control, RA (Receiving STA address), TA (Transmitting STA address), and Multi-Link element. However, the components of the frame are not limited to these.

[0091] The Frame Control field stores information indicating that the frame is a frame notified by Capabilities Exchange. The RA and TA fields store information indicating the source terminal and destination terminal, respectively. The Multi-Link element field stores information indicating whether STR transmission is possible, the links that can be used, and the number of links that can be used simultaneously for the terminal sending the frame.

[0092] The RA and TA may indicate, for example, a MAC address specific to a terminal. Furthermore, particularly when the source terminal or destination terminal is an MLD, multiple MAC addresses may be assigned to one MLD. Specifically, this is the case when a MAC address is assigned to each individual communication set within one MLD or each link used by one MLD. In other words, the 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.

[0093] The Multi-Link element stores the following fields: Element ID, Length, Element ID Extension, Multi-Link Control, MLD MAC Address, and Per-STA Profile.

[0094] The Element ID field stores information indicating that the element is a Multi-Link element. The Length field stores information indicating the bit length of the Multi-Link element. The Multi-Link Control field stores information indicating whether or not there is a subsequent MLD MAC Address. The MLD MAC Address field stores identification information that is individually assigned to MLD terminals, regardless of link or individual communication set. The Per-STA Profile field stores information about each link or each individual communication set.

[0095] The Multi-Link Control field contains the subfields MLD MAC Address Present and Rapid Non-STR Rx. The MLD MAC Address Present field contains information indicating the presence of an MLD MAC Address. The Rapid Non-STR Rx field contains information indicating that the terminal transmitting the frame can receive asynchronous transmission (i.e., asynchronous transmission in which the transmission start times are not aligned across multiple links) as shown in Figure 6 when operating as a non-STR MLD in DL Transmission.

[0096] The Per-STA Profile field stores the sub-fields of Sub element ID, Length, and Per-STA Control. Note that there may be multiple Per-STA Profiles, each representing information for a different link or individual communication set.

[0097] The Subelement ID field stores information indicating that the subfield is a Per-STA Profile. The Length field stores information indicating the bit length of the Per-STA Profile. The Per-STA Control field stores information about the link or individual communication set indicated in the Per-STA Profile field.

[0098] Specifically, the Per-STA Control field may store subfields of Link ID, Bandwidth, and Non-STR Pair Link ID. The Link ID field stores information indicating the target link or individual communication set. The Bandwidth field stores information indicating the frequency band that the link or individual communication set indicated by the Link ID can transmit through. The Non-STR Pair Link ID field stores information indicating the 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.

[0099] For example, if information indicating "Link 1" is stored in the Link ID field and information indicating "Link 2" is stored in the Non-STR Pair Link ID field, it can be interpreted that when the terminal notifying the frame receives (or transmits) using Link 1 and Link 2 simultaneously, transmission that satisfies the operational constraints of non-STR MLD is required.

[0100] E-3. DL Transmission and beyond In DL Transmission, data is transmitted from the AP MLD to the non-STR non-AP MLD. In UL Transmission, data is transmitted from the non-STR non-AP MLD to the AP MLD. As mentioned above, in this case, the AP MLD acquires the transmission right on one link (Link 1) and transmits data, but during transmission, data transmission begins on another link (Link 2). However, the end times of transmission on each link are synchronized within a certain error range.

[0101] Figure 8 shows a detailed example of the specific operation of DL Transmission and UL Transmission. The horizontal axis represents time. In Figure 8, AP MLD transmits to non-STR non-AP MLD1 on link 1, but immediately thereafter also transmits on link 2. It is assumed that, through a prior Capabilities Exchange, AP MLD knows that non-STR non-AP MLD1 supports multi-link transmission using links 1 and 2 and is capable of receiving asynchronous transmissions.

[0102] At the start of transmission, AP MLD determines that a transmission period T1 is required to transmit the PPDU previously transmitted on Link 1. After that, AP MLD acquires a new transmission right on Link 2, allowing it to transmit on Link 2 some of the data that was originally to be transmitted on Link 1, thereby shortening the PPDU transmission period on Link 1 from T1 to T2. At this time, because the receiving terminal is an NSTR, the PPDU transmission end times on Link 1 and Link 2 are aligned within a specific error range.

[0103] In the above case, the preamble in the PPDU transmitted by AP MLD on link 1 contains information indicating the PPDU length transmitted on link 1. However, because the preamble is placed at the beginning of the PPDU, even if the PPDU length is changed after the preamble is notified, the receiving terminal will not be able to recognize the changed PPDU length.

[0104] Here, it is assumed that apart from the non-STR non-AP MLD1, there are also STA2, which is a terminal that does not use link 2, and STA3, which is a terminal that does not use link 1.

[0105] When AP MLD acquires the transmission right on link 2 and can notify it, it can notify non-STR non-AP MLD1 that the transmission period on link 1 has been shortened by including information indicating that the PPDU length transmitted on link 1 has been changed from T1 to T2 in the PPDU transmitted on link 2. STA3, which is using link 2, receives a similar notification and can determine whether link 1 is in an idle state after transmission period T2. On the other hand, STA2 is not using link 2, so it is not notified that the transmission period on link 1 has been shortened from T1 to T2. For this reason, STA2 cannot determine whether link 1 is in an idle state until after T1.

[0106] Therefore, the AP MLD and non-STR non-AP MLD1 transmit another PPDU again within the transmission period T1 previously notified in the preamble of link 1. In Figure 8, of the newly transmitted PPDUs, the one transmitted on link 1 is designated PPDU #2-1, and the one transmitted on link 2 is designated PPDU #2-2. This shows an example in which both are transmitted uplink from the non-STR non-AP MLD to the AP MLD, not from the AP MLD. In other words, the non-STR non-AP MLD1 transmits to the AP MLD within the period T1 during which the transmission right acquired by the AP MLD lasts. The AP MLD can transmit another PPDU again within the period T1 by notifying the non-STR non-AP MLD of permission for uplink transmission (i.e., Reverse Direction Grant: RDG) using the RDG / More PPDU written in the PPDUs transmitted on links 1 and 2.

[0107] Figure 9 shows an example of the structure of a PPDU transmitted over link 1 and link 2. A PPDU consists of a preamble and one or more MPDUs. If necessary, the PPDU may include an area (padding) at the end to adjust the data length.

[0108] The preamble includes information necessary for a terminal receiving the PPDU to demodulate the subsequent MPDU, as well as time synchronization, frequency synchronization, and channel estimation. As described above, in addition to the information indicating the PPDU length, the preamble may also include information such as the frequency band in which the MPDU is transmitted and the MCS (Modulation and Coding Scheme) indicating the modulation and coding scheme used.

[0109] The MPDU contains data to be transmitted other than the preamble. Each MPDU may contain the fields Control, Duration, RA and TA, HT (High Throughput) Control, and Payload. The Frame Control field contains information indicating the frame type of the MPDU. The Duration field contains information indicating the transmission period in DL Transmission. The RA and TA fields contain information indicating the source terminal and destination terminal, respectively. The HT Control field contains other control information. The Payload field contains data information to be transmitted other than the above control information.

[0110] When a plurality of MPDUs are stored in a PPDU, Frame Control, Duration, RA, TA, and HT Control are stored in the first MPDU, but these do not necessarily have to be stored in subsequent MPDUs.

[0111] In particular, the HT Control field contains the subfields EHT variant ID, Control ID, and ML-CAS (Command and Status). Each of the EHT variant ID and Control ID contains information indicating the type of HT Control. The ML-CAS field contains the type of data transmitted over the link and information about links other than the link over which the frame is transmitted.

[0112] At least one of the following subfields is stored in the ML-CAS field: AC Constraint, RDG / More PPDU, Support Link Effort, Basic Link Overwrite Flag, and Renewal Length.

[0113] The AC Constraint field stores information indicating that there are restrictions on the traffic types that can be transmitted in the DL Transmission. The RDG / More PPDU field stores information indicating either (1) or (2) below.

[0114] (1) Information indicating that, if the terminal transmitting the frame has acquired the transmission right, the destination terminal is permitted to transmit within the scope of the transmission right (i.e., Reverse Direction Grant: RDG). (2) When permission is notified in (1) and a PPDU is to be transmitted, this information indicates whether a subsequent PPDU exists.

[0115] The Support Link Effort field stores information indicating whether the terminal that notifies the frame is attempting to acquire the transmission right on a link other than the link notified by the frame.

[0116] The Basic Link Overwrite Flag field stores information indicating to the receiving terminal whether or not to overwrite some of the information contained in the preamble and ML-CAS when a link other than the link notifying the frame is already being used for transmission.

[0117] The Renewal Length field is included in the PPDU sent on link 2, and stores information indicating the change in the PPDU length of link 1 or the PPDU length of link 1 after the change.

[0118] For example, in DL Transmission, the MPDU in PPDU #1-1 transmitted by AP MLD on link 1 contains a Support Link Effort subfield, and PPDU #1-2 transmitted by AP MLD on link 2 contains a Basic Link Overwrite Flag subfield and a Renewal Length subfield.

[0119] In the operation example shown in Fig. 8, the AP MLD can indicate in the Support Link Effort field of the PPDU transmitted on Link 1 (i.e., Basic Link) that it is attempting to acquire the transmission right on Link 2 (i.e., Support Link). Furthermore, when Link 2 (i.e., Support Link) is already being used for transmission, the AP MLD can indicate in the Basic Link Overwrite Flag subfield that the information included in the ML-CAS (specifically, the change in the PPDU length of Link 1 (i.e., Basic Link) or the changed PPDU length of Link 1, which is written in the subsequent Renewal Length field) has been overwritten.

[0120] 9 shows that ML-CAS is stored in each MPDU, but it is not necessary that ML-CAS be stored in every MPDU. For example, ML-CAS may be stored only in the first MPDU, or ML-CAS may be stored in the preamble rather than in an MPDU.

[0121] Referring again to Figure 8, in order to perform transmission not only on Link 1 but also on Link 2 during the shortened period on Link 1, information indicating T3' in Figure 8 is stored in the Duration field of PPDU #1-2 transmitted on Link 2. Furthermore, the RDG / More PPDU subfields of the PPDUs transmitted on Link 1 and Link 2 contain information indicating to the non-STR non-AP MLD that it may transmit data to the AP MLD within the period of T3' (i.e., Reverse Direction Grant: RDG). By indicating permission to transmit within transmission period T1 in the RDG / More PPDU field of each PPDU transmitted by the AP MLD on Link 1 and Link 2, the non-STR non-AP MLD can again transmit another (i.e., uplink) PPDU on Link 1 and Link 2 during transmission period T1.

[0122] E-4. Control operation of non-STR non-AP MLD1 10 shows an example of the operation of each logical entity in the communication unit 410 in non-STR non-AP MLD1 in which PPDU #1-1 and PPDU #1-2 are notified in DL Transmission. The horizontal axis represents the time axis. In FIG. 10, multiple MPDUs in a PPDU are collectively referred to as a PSDU (PHY Service Data Unit).

[0123] Within the communication unit 410, an individual control unit 1 for link 1 and an individual control unit 2 for link 2 are arranged. The individual control unit 1 and individual control unit 2 are respectively composed of logical entities: PHY Layer #1 and PHY Layer #2 that control the physical layers of link 1 and link 2, and MAC Lower Sublayer #1 and MAC Lower Sublayer #2 that control data processing of link 1 and link 2. Furthermore, within the communication unit 410, a Common Entity is arranged as a logical entity that controls data processing common to link 1 and link 2.

[0124] Furthermore, information is exchanged between layers and between layers and entities, and this interface is also called a Service Access Point (SAP). In the common entity, in addition to parameters used by the common data processing unit 413 in the communication unit 410, parameters to be applied in each MAC lower sublayer and PHY layer are calculated.

[0125] The PHY layer is composed of the antenna 440, the amplifier 417 in the communication unit 410, the wireless interface unit 416, the signal processing unit 415, and the individual control unit 414, and the MAC lower sublayer is composed of the individual data processing unit 414 in the communication unit 410 and the corresponding individual control unit in the communication control unit 411. However, the components of the PHY layer and the MAC lower sublayer are not limited to these.

[0126] In a normal communication operation, an Ack is sent from the non-STR non-AP MLD1 when each PSDU is received, but for the sake of convenience, this sequence of events is omitted from Fig. 10. For example, within period T3, in addition to receiving a PSDU including a preamble and padding, an Ack is sent, but for the sake of convenience, the description of the Ack transmission is omitted from Fig. 10.

[0127] The information communicated between the entities and the operation of each entity will be described below with reference to FIG.

[0128] 10, data transmitted from AP MLD1 in link 1 is received by PHY Layer #1, demodulated, and then the MPDU is passed to MAC Lower Sublayer #1. A similar operation is performed in link 2.

[0129] E-4-1. PHY Layer operation in link 1, information transmitted between PHY and MAC The arrow indicated by reference number 1001 in Figure 10 indicates the operation in which, based on the information indicated in the preamble, each MPDU is notified from PHY Layer #1 to MAC Lower Sublayer #1, in addition to control information such as received power (RSSI: Received Signal Strength Indicator), number of spatial streams, and PPDU format (hereinafter also referred to as RXVECTOR).

[0130] Based on the information in the preamble, PHY Layer #1 calculates the demodulation operation period T1 and performs demodulation. After the demodulation operation is completed, PHY Layer #1 notifies MAC Lower Sublayer #1 that reception is complete. The calculated T1 determines the time when this PSDU reception completion notification is issued (the end of period T1 in the example shown in Figure 10). The arrow indicated by reference number 1001' in Figure 10 indicates the reception completion notification. This reception completion notification not only notifies the MAC Lower Sublayer #1 of the completion of reception, but also notifies the MAC Lower Sublayer #1 of the availability of the channel determined by PHY Layer #1.

[0131] If the received signal is lost (carrier lost) within the period T1, PHY Layer #1 does not need to perform demodulation.

[0132] E-4-2. Operation of the MAC Lower Sublayer in Link 1, and information transmitted between the MAC Lower and Common Entity After receiving the notification indicated by arrow 1001 from PHY Layer #1, MAC Lower Sublayer #1 analyzes the information included in the MPDU and notifies the common entity of the necessary information. The arrow indicated by reference number 1002 in FIG. 10 indicates this notification. For example, MAC Lower Sublayer #1 analyzes whether the Support Link Effort subfield in the MPDU indicates that AP MLD is attempting to acquire the transmission right on link 2, and notifies the common entity of this information. Similarly, MAC Lower Sublayer #1 may analyze whether the RDG / More PPDU subfield indicates that another transmission is permitted within the period T1, and notify the common entity of the information indicated in this field.

[0133] If the preamble contains Support Link Effort, the information in Support Link Effort may be analyzed in the PHY Layer #1 in a similar manner, and the information may be notified to the Common Entity via the MAC Lower Sublayer #1.

[0134] E-4-3. PHY Layer operation in link 2, information transmitted between PHY and MAC As described in section E-4-1 above, as indicated by the arrow with reference number 1003 in Figure 10, PHY Layer #2 notifies MAC Lower Sublayer #2 of each MPDU, in addition to control information (RXVECTOR) such as received power (RSSI), number of spatial streams, and PPDU format, based on the information indicated in the preamble.

[0135] Based on the information in the preamble, PHY Layer #2 calculates the demodulation operation period T3 and performs demodulation. After the demodulation operation is completed, PHY Layer #2 notifies MAC Lower Sublayer #2 that reception is complete. The calculated T3 determines the time when this PSDU reception completion notification is issued (the end of period T3 in the example shown in Figure 10). The arrow indicated by reference number 1003' in Figure 10 indicates the reception completion notification. This reception completion notification not only notifies the MAC Lower Sublayer #2 that reception is complete, but also notifies the MAC Lower Sublayer #2 of the channel availability status determined by PHY Layer #2.

[0136] If the received signal is lost (carrier lost) within the period T3, PHY Layer #2 does not need to perform demodulation.

[0137] E-4-4. MAC Lower Sublayer Operation in Link 2, Information Transmitted Between MAC Lower and Common Entity After receiving the notification indicated by arrow 1003 from PHY Layer #2, the MAC Lower Sublayer #2 analyzes the information contained in the MPDU and notifies the Common Entity of the necessary information. The arrow indicated by reference number 1004 in FIG. 10 indicates this notification. For example, the MAC Lower Sublayer #2 analyzes the reception of a signal from the AP MLD and the information indicated in the ML-CAS including the Renewal Length (i.e., information indicating changes to the information indicated in the preamble notified on Link 1), and notifies the Common Entity of this information. For example, the MAC Lower Sublayer #2 analyzes whether the Basic Link Overwrite Flag subfield indicates that the preamble already transmitted on Link 1 and the information in the ML-CAS are to be overwritten, and notifies the Common Entity of this indication and the information to be changed. Similarly, the MAC Lower Sublayer #2 may analyze the RDG / More PPDU subfield to determine whether permission for another transmission within the period T1 is indicated, and notify the Common Entity of the information indicated in this field.

[0138] In addition, if the preamble includes an ML-CAS field, the information in the ML-CAS field may be analyzed in the same manner in PHY Layer #1, and the information may be notified to the Common Entity via MAC Lower Sublayer #1.

[0139] E-4-5. Common Entity Operation Based on the notification from the MAC Lower Sublayer #2, the Common Entity notifies the PHY Layer #1 or MAC Lower Sublayer #1 of the link 1 included in the individual control unit 1 of information indicating at least the changed reception period (or reception end time), as indicated by the arrows of reference numbers 1005 and 1006 in Fig. 10. At this time, the Common Entity has been notified of the following information (1) and (2) from the PHY Layer of each link via the MAC Lower Sublayer:

[0140] (1) Information indicating that AP MLD is attempting to acquire transmission rights on Link 2 (2) Information indicating that the information notified by the preamble on Link 1 is to be changed

[0141] Note that if it is indicated that the information in the ML-CAS notified via link 1 is to be changed, the Common Entity may also notify the MAC Lower Sublayer #1 of this information. That is, if the RDG / More PPDU subfield in the ML-CAS notified via link 2 contains information indicating that transmission from non-STR non-AP MLD1 to AP MLD is permitted during the redundant period resulting from the shortened reception period, the Common Entity notifies the MAC Lower Sublayer #1 or PHY Layer #1 of this information. In Fig. 10, the Common Entity notifies the PHY Layer #1 via the MAC Lower Sublayer #1, but the Common Entity may also notify the PHY Layer #1 directly.

[0142] FIG. 11 shows in the form of a flowchart the operations performed by a common entity in a non-STR non-AP MLD.

[0143] When the Common Entity is notified by MAC Lower Sublayer #1 that Support Link Effort="1" is indicated in the PPDU transmitted over Link 1 (Yes in step S1101), it checks whether it has been notified by MAC Lower Sublayer #2 that Basic Link Overwrite Flag="1" is indicated in the PPDU transmitted over Link 2 (step S1102).

[0144] If the Basic Link Overwrite Flag="1" is notified from the MAC Lower Sublayer #2 (Yes in step S1102), the transmission time of the PPDU on link 1 has been shortened, and the Common Entity notifies the individual control unit 1 of the shortened reception end time based on the Renewal Length information notified from the MAC Lower Sublayer #2 (step S1103).

[0145] On the other hand, if the Basic Link Overwrite Flag="1" has not been notified from the MAC Lower Sublayer #2 (No in step S1102), the PPDU transmission time on link 1 has not been shortened, so the Common Entity does not notify the individual control unit 1 of the shortened reception end time (step S1104). In other words, the demodulation process continues on each link.

[0146] E-4-6. Notification of reception end time When the PHY Layer #1 is notified of a change in the reception period directly or indirectly from the Common Entity, it notifies the MAC Lower Sublayer #1 of the reception end time at the reception end time changed based on the notified information, as indicated by the arrow with reference number 1007 in Fig. 10. At this time, the PHY Layer #1 may notify the MAC Lower Sublayer #1 of the availability of the channel.

[0147] Furthermore, at the time when the PHY Layer #2 issues a notification of the end of reception of the PSDU transmitted on the link 2, the PHY Layer #2 notifies the MAC Lower Sublayer #2 of the end of reception, as indicated by the arrow with reference number 1003' in FIG.

[0148] Here, the operation of the MAC Lower Sublayer #1 when a notification is sent to the PHY Layer #1 as indicated by the arrow 1006 in FIG. 10, and when a notification is sent from the PHY Layer #1 as indicated by the arrow 1007, will be explained in more detail.

[0149] The timing at which the MAC Lower Sublayer #1 notifies the PHY Layer #1 may be after all data (MPDUs) have been notified from the PHY Layer #1 to the MAC Sublayer #1.

[0150] For example, when an MPDU is notified from PHY Layer #1 to MAC Lower Sublayer #1 one octet (byte at a time), the post-change transmission data length of Link 1 can be estimated based on the information indicated by the Renewal Length notified from PHY Layer #2. Therefore, after PHY Layer #1 notifies MAC Lower Sublayer #1 of data with the number of octets equivalent to the estimated post-change transmission data length, MAC Lower Sublayer #1 may notify PHY Layer #1 of information indicating a request to terminate reception operation in PHY Layer #1. Upon receiving this request, PHY Layer #1 may notify MAC Lower Sublayer #1 of at least one of the reception end time and channel availability information.

[0151] According to Non-Patent Document 1, the data notified from PHY Layer #1 to MAC Lower Sublayer #1 for each octet is notified by PHY-DATA.indication.

[0152] E-4-7. Details of Common Entity and MAC Lower Sublayer Operation When the Common Entity receives notification of the reception end time from each PHY layer, it performs the following operations (1) to (3) on the MAC Lower Sublayer, as indicated by the arrow with reference number 1008 in FIG.

[0153] (1) Generation of a response confirmation frame The Common Entity generates the information necessary to generate a response confirmation frame when an error is detected in the received MPDU. For example, if the received MPDU is managed by a certain number (such as a sequence number), it determines which MPDU number was received correctly or not, and passes the recorded information to each MAC Lower Sublayer.

[0154] (2) Generating information necessary for preamble generation The Common Entity passes control information required for non-STR non-AP MLD operation to the MAC Lower Sublayer or PHY Layer. This control information includes information indicating synchronous transmission over multiple links as non-STR non-AP MLD and information indicating the length of the PPDU generated by the PHY Layer.

[0155] (3) Delivering the MPDU to be transmitted to each MAC Lower Sublayer or each PHY Layer The Common Entity delivers MPDU information corresponding to the data to be transmitted to each MAC Lower Sublayer or each PHY Layer (corresponding to the operation indicated by arrow 1009 in FIG. 10). At this time, the length of the data to be transmitted is within a range not exceeding the period T1 in link 1, and is indicated as T2' in FIG. 10. In addition, the type of data may be restricted according to the information indicated in the AC Constraint notified immediately before from the AP MLD. For example, if transmission of only prioritized data such as voice communication is permitted, the Common Entity delivers only permitted data to the MAC Lower Sublayer or PHY Layer, and controls the PHY Layer to transmit only this data.

[0156] The above (1) to (3) may be partially performed by the MAC Lower Sublayer, in addition to the Common Entity, as necessary.

[0157] After each MAC lower sublayer passes information to each PHY layer, each PHY layer simultaneously transmits a PPDU. At this time, the acknowledgement frame and the MPDU representing the received data may be transmitted together in a single PPDU.

[0158] F. Second Example In the first embodiment described above in Section E, a multi-link transmission method was described in which, during the redundant period, non-STR non-AP MLD1 simultaneously uses link 1 and link 2. In contrast, in the second embodiment described in this Section F, during the redundant period, non-STR non-AP MLD1 transmits using only link 1, while another STA (STA2 in the example shown in FIG. 12) transmits on link 2 for that period or longer.

[0159] Fig. 12 shows an example of a communication sequence performed in a wireless network system as a second embodiment. The vertical axis represents time. In the first embodiment shown in Fig. 5, UL transmission is performed only with non-STR non-AP MLD in the redundant period after DL transmission. In contrast, in the second embodiment shown in Fig. 12, UL transmission is performed from another STA (STA2 in the example shown in Fig. 12) in the redundant period after DL transmission. Note that the operations of Capabilities Exchange and DL transmission are basically the same as those in the first embodiment.

[0160] F-1. DL Transmission and UL Transmission Operation Fig. 13 shows in detail specific examples of the operation of DL Transmission and UL Transmission. The horizontal axis represents the time axis. In Fig. 8, AP MLD transmits to non-STR non-AP MLD1 on link 1, and immediately thereafter also transmits on link 2. In contrast, in Fig. 13, after AP MLD transmits PPDU#1-2 on link 2, AP MLD notifies other terminals of Enhanced CF (Contention Free)-End, indicating the release of the transmission right for link 2.

[0161] At the start of transmission, AP MLD determines that a transmission period of T1 is required to transmit the PPDU previously transmitted on Link 1. After that, AP MLD acquires a new transmission right on Link 2, allowing it to transmit on Link 2 some of the data that was originally to be transmitted on Link 1, thereby shortening the PPDU transmission period on Link 1 to T2. At this time, the PPDU transmission end times on Link 1 and Link 2 are aligned within a specific error range.

[0162] In the above case, the preamble in the PPDU sent by AP MLD on link 1 contains information indicating the PPDU length transmitted on link 1. Because the preamble is placed at the beginning of the PPDU, even if the PPDU length is changed after the preamble is notified, the receiving terminal will not be able to recognize the changed PPDU length.

[0163] In addition to the non-STR non-AP MLD1, assume that there exists STA2, a terminal that does not use link 2, and STA3, a terminal that does not use link 1. After the AP MLD transmits PPDU #1-2 on link 2, if it is acceptable to allow transmission from terminals other than the non-STR non-AP MLD1, it sends an Enhanced CF-End to the other terminals, indicating the release of the transmission right. Therefore, if STA3 subsequently obtains the transmission right on link 2, it can transmit PPDU #3. The AP MLD includes a transmission prohibition period for the non-STR non-AP MLD1 in the Enhanced CF-End (in the example shown in FIG. 13, the transmission prohibition period is T3'-T3). Upon receiving this Enhanced CF-End, the non-STR non-AP MLD1 refrains from obtaining the transmission right for the specified transmission prohibition period. The frame structure of the Enhanced CF-End will be explained in the next section F-2 with reference to FIG. 14.

[0164] In addition, the AP MLD indicates permission for transmission within the transmission period T1 in the RDG / More PPDU field of the PPDU transmitted over link 1, so that the non-STR non-AP MLD can transmit another PPDU (i.e., uplink) over link 1 within the transmission period T1. In addition, the AP MLD indicates prohibition of transmission within the transmission period T1 in the RDG / More PPDU field of the PPDU transmitted over link 2, so that the non-STR non-AP MLD does not transmit another PPDU over link 1 within the transmission period T1.

[0165] F-2. Overview of Enhanced CF-End An example of the structure of a frame notified by Enhanced CF-End is shown in Figure 14. Enhanced CF-End is a frame for notifying the communication partner of a multi-link transmission including the link of a transmission prohibition period in the link, and by transmitting this frame, it is possible to indicate to other terminals that the transmission right for the link has been released.

[0166] The frame shown in FIG. 14 includes the fields Frame Control, Duration, RA, BSSID or TA, HT Control, and FCS, but may also include other components not shown.

[0167] The Frame Control field stores information indicating that the frame is Enhanced CF-End. The Duration field stores information indicating the time to transmit the frame as well as the period for obtaining the transmission period. The RA field stores information indicating one or more destination terminals. The BSSID (TA) field stores information indicating the terminal to which the frame is to be sent or the BSSID to which the terminal to which the frame is to be sent belongs. The HT Control field stores other control information. The FCS (Frame Check Sequence) field stores information for error correction to be performed when the frame is received.

[0168] Of the above, the HT Control field includes the subfields EHT variant ID, Control ID, STA ID, and Prohibited period.

[0169] The subfields EHT variant ID and Control ID store information indicating the type of HT Control. The STA ID field stores identification information of a terminal that is prohibited from being used as a transmission destination. The Prohibited period stores information indicating a period during which transmission to the terminal specified in the STA ID field is prohibited. The STA ID field may also store information indicating the MAC address of the terminal in question on the link.

[0170] 13, information indicating non-STR non-AP MLD1 is stored in the STA ID field in the Enhanced CF-End frame, and information indicating the transmission prohibition period (T3'-T3) is stored in the Prohibited period. Therefore, a terminal that receives the Enhanced CF-End frame refrains from transmitting to non-STR non-AP MLD1 during the transmission prohibition period (T3'-T3). Note that the STA ID field may also store information indicating the MAC address of non-STR non-AP MLD1 on link 2.

[0171] A terminal that has received an Enhanced CF-End frame is restricted from notifying information to non-STR non-AP MLD1 for a specific period based on the information indicated in the STA ID and Prohibited period subfields.

[0172] F-3. Control operation of non-STR non-AP MLD1 15 shows an example of the operation of the communication unit 410 in the non-STR non-AP MLD1 in which PPDU #1-1 and PPDU #1-2 are notified in DL Transmission. The horizontal axis represents the time axis. In FIG. 15, multiple MPDUs in a PPDU are collectively referred to as a PSDU.

[0173] The communication unit 410 includes an individual control unit 1 for link 1 and an individual control unit 2 for link 2. The individual control units 1 and 2 are respectively configured with the logical entities of PHY Layer #1 and PHY Layer #2, which control the physical layers of link 1 and link 2, and MAC Lower Sublayer #1 and MAC Lower Sublayer #2, which control data processing of link 1 and link 2. The communication unit 410 also includes a Common Entity, which is a logical entity that controls data processing common to link 1 and link 2. Information is exchanged between layers and between layers and entities via SAP. The Common Entity calculates parameters to be applied to each MAC Lower Sublayer and PHY Layer in addition to parameters used by the common data processing unit 413 in the communication unit 410. In a normal communication operation, an Ack is transmitted from the non-STR non-AP MLD1 upon receiving each PSDU, but for convenience of explanation, the sequence of events related to the transmission of the Ack is omitted in FIG. 15.

[0174] The control operations from receiving the preamble on link 1 to notifying the reception end time are the same as those in the first embodiment (see above items E-4-1 to E-4-6), and therefore will not be described here.

[0175] When the Common Entity receives notification of the reception end time from each PHY layer, it performs the following operations (1) to (3) on the MAC Lower Sublayer, as indicated by the arrow with reference number 1508 in FIG.

[0176] (1) Generation of a response confirmation frame The Common Entity generates the information necessary to generate a response confirmation frame when an error is detected in the received MPDU. For example, if the received MPDU is managed by a certain number (such as a sequence number), it determines which MPDU number was received correctly or not, and passes the recorded information to each MAC Lower Sublayer.

[0177] (2) Generating information necessary for preamble generation The Common Entity passes control information required for non-STR non-AP MLD operation to the MAC Lower Sublayer or PHY Layer. This control information includes information indicating synchronous transmission over multiple links as non-STR non-AP MLD and information indicating the length of the PPDU generated by the PHY Layer.

[0178] (3) Delivering the MPDU to be transmitted to each MAC Lower Sublayer or each PHY Layer The Common Entity delivers MPDU information corresponding to the data to be transmitted to each MAC Lower Sublayer or each PHY Layer (corresponding to the operation indicated by arrow 1509 in FIG. 15). At this time, the length of the data to be transmitted is within a range not exceeding period T1 on link 1, and is indicated as T2' in FIG. 15.

[0179] The above (1) to (3) may be partially performed by the MAC Lower Sublayer, in addition to the Common Entity, as necessary.

[0180] Furthermore, when the Common Entity receives notification of the reception end time from each PHY layer, it notifies the individual communication unit 2 of link 2 of a transmission prohibition period as an operation (corresponding to arrow 1508 in FIG. 15 ) to the individual communication unit 2 of link 2. In other words, the Common Entity notifies link 2 of information indicating that transmission is prohibited for at least the transmission period of PPDU#2-1.

[0181] F-4.STA3 Operation Other terminals notified of the Enhanced CF-End frame refrain from transmitting to the terminal specified in the STA ID field in the Enhanced CF-End frame for the period specified in the Prohibited period. 13, after completing multilink transmission using link 1 and link 2, the AP MLD transmits an Enhanced CF-End frame on link 2. In this Enhanced CF-End frame, the AP MLD notifies the non-STR non-AP MLD1 of the transmission prohibition period (T3'-T3). A terminal notified of Enhanced CF-End on link 2 transmits to terminals other than non-STR non-AP MLD 1. In Fig. 13, a terminal other than AP MLD, i.e., STA3, is shown transmitting on link 2, but AP MLD may also transmit on link 2 to terminals other than non-STR non-AP MLD.

[0182] G. Third Example In the above first and second embodiments, the case where the receiving terminal of the DL transmission is a non-STR non-AP MLD is described, but in the third embodiment, the case where the receiving terminal of the DL transmission is a STR non-AP MLD is described. Therefore, in the third embodiment, the transmission end times of the PPDUs transmitted to the receiving terminals on each link do not need to be the same.

[0183] Fig. 16 shows an example of a communication sequence performed in a wireless network system as a third embodiment. The vertical axis represents time. Here, a wireless network system is assumed in which one AP MLD, one STR non-AP MLD, and one or more STAs (hereinafter referred to as "STAs") exist. The example of the communication sequence shown in Fig. 16 shows the following four types of transmission. Details of the frames notified in each transmission will be described later.

[0184] (1) Capabilities Exchange: Notification of information indicating the capabilities of each device (2) DL Transmission: Data transmission from AP MLD to STR non-AP MLD (3) UL Transmission: Data transmission from STR non-AP MLD to AP MLD (4) Ack: Acknowledgment of receipt of each data transmission in (2) and (3) above

[0185] G-1. Points to note Before describing each transmission, a few points should be noted.

[0186] G-1-1. Points to note regarding transmission rights 16 shows the sequence of transmission between AP MLD and STR non-AP MLD, but does not show transmission with STAs. This is because FIG. 16 shows an example in which AP MLD or STR non-AP MLD acquires the transmission right before STAs and performs each transmission. Although not shown, transmission from or to STAs may occur. For example, DL transmission may be performed after transmission occurs between AP MLD and some STAs immediately after Capabilities Exchange.

[0187] In DL transmission, while transmission is taking place on one link (hereinafter referred to as "Link 1"), transmission on another link occurs. In addition, two ACKs and UL transmissions may be performed within the transmission right (the period during which transmission is permitted) secured by the transmission on Link 1.

[0188] G-1-2. Points to note regarding DL Transmission As described above, in DL Transmission, while transmission is taking place on one link (link 1), transmission is taking place on another link (link 2).

[0189] Figure 17 shows an example of an operation in which transmission is performed on link 1 and link 2 in DL Transmission. The horizontal axis represents time. This figure shows an example in which there are two links, link 1 and link 2, and transmission on link 2 occurs after transmission on link 1 starts.

[0190] The AP MLD transmits a data unit (PPDU) on link 1. Control information such as the PPDU length is contained in the preamble, which is the beginning of the PPDU. The preamble is followed by the MPDU, which is the data. Note that if the receiving terminal is an STR MLD, the transmission end time or reception end time of each PPDU does not need to be the same.

[0191] G-1-3. Points to note regarding transmission order 16 shows a case where Capabilities Exchange is performed from the AP MLD to the STR non-AP MLD, but it may also be transmitted simultaneously to the STR non-AP MLD and STAs. As a specific example, it may be performed using a beacon signal that the AP MLD periodically transmits to multiple nearby terminals.

[0192] Although not shown in Fig. 16, Capabilities Exchange may also occur from STAs to AP MLD. As a specific example, after AP MLD transmits a beacon signal, the STAs may transmit the Capabilities Exchange to AP MLD. Note that the order of Capabilities Exchange performed by STR non-AP MLD and STAs is not particularly limited.

[0193] Each sequence may be partially omitted as necessary, and the order may not be as shown in Fig. 16. For example, if it is determined that an Ack is not necessary depending on the type of data being transmitted, an Ack may not be sent.

[0194] G-2.Capabilities Exchange AP MLD and STR non-AP MLD communicate with each other information about their own capabilities (Capabilities Exchange). The capabilities here refer to, but are not limited to, whether a terminal can perform STR transmission and the number of links that can transmit simultaneously. Capability Exchange may be included in, for example, a beacon signal periodically transmitted by each terminal or in an information notification (Association) for establishing a connection between terminals after a beacon signal.

[0195] Figure 18 shows an example of the structure of a frame notified in Capabilities Exchange. The frame shown in the figure is composed of the fields Frame Control, RA, TA, and Multi-Link element. However, the components of the frame are not limited to these.

[0196] The Frame Control field stores information indicating that the frame is a frame notified by Capabilities Exchange. The RA and TA fields store information indicating the source terminal and destination terminal, respectively. The Multi-Link element field stores information indicating whether STR transmission is possible, the links that can be used, and the number of links that can be used simultaneously for the terminal sending the frame.

[0197] The RA and TA may indicate, for example, a MAC address specific to a terminal. Furthermore, particularly when the source terminal or destination terminal is an MLD, multiple MAC addresses may be assigned to one MLD. Specifically, this is the case when a MAC address is assigned to each individual communication set within one MLD or each link used by one MLD. In other words, the 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.

[0198] The Multi-Link element stores the following fields: Element ID, Length, Element ID Extension, Multi-Link Control, MLD MAC Address, and Per-STA Profile.

[0199] The Element ID field stores information indicating that the element is a Multi-Link element. The Length field stores information indicating the bit length of the Multi-Link element. The Multi-Link Control field stores information indicating whether or not there is a subsequent MLD MAC Address. The MLD MAC Address field stores identification information that is individually assigned to MLD terminals, regardless of link or individual communication set. The Per-STA Profile field stores information about each link or each individual communication set.

[0200] The Multi-Link Control field stores the subfields MLD MAC Address Present and Rapid STR Rx. The MLD MAC Address Present field stores information indicating the presence of an MLD MAC Address. The Rapid STR Rx field stores information indicating that the terminal transmitting the frame can receive asynchronous transmission as shown in Figure 17 when operating as an STR MLD in DL Transmission.

[0201] The Per-STA Profile field stores the subfields Subelement ID, Length, and Per-STA Control. Note that there may be multiple Per-STA Profiles, each representing information for a different link or individual communication set.

[0202] The Subelement ID field stores information indicating that the subfield is a Per-STA Profile. The Length field stores information indicating the bit length of the Per-STA Profile. The Per-STA Control field stores information about the link or individual communication set indicated in the Per-STA Profile field.

[0203] Specifically, the Per-STA Control field may store subfields of Link ID, Bandwidth, and STR Pair Link ID. The Link ID field stores information indicating the target link or individual communication set. The Bandwidth field stores information indicating the frequency band that the link or individual communication set indicated by the Link ID can transmit through. The STR Pair Link ID field stores information indicating the link or individual communication set that operates as an STR MLD when used simultaneously with the link or individual communication set indicated by the Link ID.

[0204] For example, if information indicating "Link 1" is stored in the Link ID field and information indicating "Link 2" is stored in the STR Pair Link ID field, it can be interpreted that the terminal notifying the frame can perform transmission as STR MLD if it receives (or transmits) using Link 1 and Link 2 simultaneously.

[0205] G-3. DL Transmission and beyond In DL transmission, data is transmitted from the AP MLD to the STR non-AP MLD, and in UL transmission, data is transmitted from the STR non-AP MLD to the AP MLD. As mentioned above, in this case, the AP MLD acquires the transmission right on one link (link 1) and transmits data, but during transmission, data transmission begins on another link (link 2).

[0206] Figure 19 shows a detailed example of the specific operation of DL Transmission and UL Transmission. The horizontal axis represents time. In Figure 19, AP MLD transmits to STR non-AP MLD1 on link 1, but immediately thereafter also transmits on link 2. It is assumed that, through a prior Capabilities Exchange, AP MLD knows that STR non-AP MLD1 supports multi-link transmission using links 1 and 2 and is capable of receiving asynchronous transmission.

[0207] At the start of transmission, AP MLD determines that a transmission period of T1 is required to transmit the PPDU previously transmitted on link 1. After that, AP MLD acquires a new transmission right on link 2, allowing it to transmit on link 2 some of the data that was originally to be transmitted on link 1, thereby shortening the PPDU transmission period on link 1 to T2. At this time, because the receiving terminal is an STR, the PPDU transmission end times on links 1 and 2 can be any time and do not need to be the same.

[0208] In the above case, the preamble in the PPDU transmitted by AP MLD on link 1 contains information indicating the PPDU length transmitted on link 1. However, because the preamble is placed at the beginning of the PPDU, even if the PPDU length is changed after the preamble is notified, the receiving terminal will not be able to recognize the changed PPDU length.

[0209] Here, it is assumed that, apart from STR non-AP MLD1, there exist STA2, which is a terminal that does not use link 2, and STA3, which is a terminal that does not use link 1.

[0210] When the AP MLD acquires the transmission right on link 2 and can notify it, it can notify the STR non-AP MLD1 that the transmission period on link 1 has been shortened by including information indicating that the PPDU length transmitted on link 1 has been changed from T1 to T2 in the PPDU transmitted on link 2. STA3, which is using link 2, receives a similar notification and can determine whether link 1 is in an idle state after transmission period T2. On the other hand, since STA2 is not using link 2, it is not notified that the transmission period on link 1 has been shortened from T1 to T2. For this reason, STA2 cannot determine whether link 1 is in an idle state until after T1.

[0211] Therefore, the AP MLD and STR non-AP MLD1 transmit another PPDU again within the transmission period T1 previously notified in the preamble for link 1. In FIG. 19, of the newly transmitted PPDUs, the one transmitted over link 1 is designated PPDU #2-1, and the one transmitted over link 2 is designated PPDU #2-2. It is shown that both are transmitted from the STR non-AP MLD to the AP MLD, not from the AP MLD. In other words, the STR non-AP MLD1 transmits to the AP MLD within the period T1 during which the transmission right acquired by the AP MLD lasts. The AP MLD can transmit another PPDU again within the period T1 by notifying the STR non-AP MLD of permission for uplink transmission (i.e., Reverse Direction Grant: RDG) using the RDG / More PPDU written in the PPDUs transmitted over link 1 and link 2.

[0212] 19 shows an example in which the transmission end times of PPDU#2-1 and PPDU#2-2 are aligned, but because the source non-AP MLD is an STR, the transmission end times do not need to be aligned. The STR non-AP MLD returns an Ack for PPDU#1-1 on link 1 before it finishes receiving PPDU#1-2 from the AP MLD on link 2.

[0213] Fig. 20 shows an example of the structure of a PPDU transmitted over link 1 and link 2. A PPDU consists of a preamble and one or more MPDUs. If necessary, the PPDU may include an area (padding) at the end to adjust the data length.

[0214] The preamble contains information necessary for the terminal receiving the PPDU to demodulate the following MPDU, as well as time synchronization, frequency synchronization, and channel estimation. As described above, in addition to the information indicating the PPDU length, the preamble may also contain information such as the frequency band in which the MPDU is transmitted and the MCS used.

[0215] The MPDU contains data to be transmitted other than the preamble. Each MPDU may contain the fields Control, Duration, RA and TA, HT Control, and Payload. The Frame Control field contains information indicating the frame type of the MPDU. The Duration field contains information indicating the transmission period in DL Transmission. The RA and TA fields contain information indicating the source terminal and destination terminal, respectively. The HT Control field contains other control information. The Payload field contains data information to be transmitted other than the above control information.

[0216] When a plurality of MPDUs are stored in a PPDU, Frame Control, Duration, RA, TA, and HT Control are stored in the first MPDU, but these do not necessarily have to be stored in subsequent MPDUs.

[0217] In particular, the HT Control field contains the subfields EHT variant ID, Control ID, and ML-CAS. Each of the EHT variant ID and Control ID contains information indicating the type of HT Control. The ML-CAS field contains the type of data transmitted over the link and information about links other than the link over which the frame is transmitted.

[0218] At least one of the following subfields is stored in the ML-CAS field: AC Constraint, RDG / More PPDU, Support Link Effort, Basic Link Overwrite Flag, and Renewal Length.

[0219] The AC Constraint field stores information indicating that there are restrictions on the traffic types that can be transmitted in the DL Transmission. The RDG / More PPDU field stores information indicating either (1) or (2) below.

[0220] (1) Information indicating that, if the terminal transmitting the frame has acquired the transmission right, the destination terminal is permitted to transmit within the scope of the transmission right (i.e., Reverse Direction Grant: RDG). (2) When permission is notified in (1) and a PPDU is to be transmitted, this information indicates whether a subsequent PPDU exists.

[0221] The Support Link Effort field stores information indicating whether the terminal that notifies the frame is attempting to acquire the transmission right on a link other than the link notified by the frame.

[0222] The Basic Link Overwrite Flag field stores information indicating to the receiving terminal whether or not to overwrite some of the information contained in the preamble and ML-CAS when a link other than the link notifying the frame is already being used for transmission.

[0223] The Renewal Length field is included in the PPDU sent on link 2, and stores information indicating the change in the PPDU length of link 1 or the PPDU length of link 1 after the change.

[0224] For example, in DL Transmission, the MPDU in PPDU #1-1 transmitted by AP MLD on link 1 contains a Support Link Effort subfield, and PPDU #1-2 transmitted by AP MLD on link 2 contains a Basic Link Overwrite Flag subfield and a Renewal Length subfield.

[0225] In the operation example shown in Fig. 19, the AP MLD can indicate in the Support Link Effort field of the PPDU transmitted on Link 1 (i.e., Basic Link) that it is attempting to acquire the transmission right on Link 2 (i.e., Support Link). Furthermore, when Link 2 (i.e., Support Link) is already being used for transmission, the AP MLD can indicate in the Basic Link Overwrite Flag subfield that the information included in the ML-CAS (specifically, the change in the PPDU length of Link 1 (i.e., Basic Link) or the changed PPDU length of Link 1, which is written in the subsequent Renewal Length field) has been overwritten.

[0226] 20 shows that ML-CAS is stored in each MPDU, but it is not necessary that ML-CAS be stored in every MPDU. For example, ML-CAS may be stored only in the first MPDU, or ML-CAS may be stored in the preamble rather than in an MPDU.

[0227] 19 again, in order to perform transmission not only on Link 1 but also on Link 2 during the shortened period on Link 1, information indicating T3' in FIG. 19 is stored in the Duration field of PPDU #1-2 transmitted on Link 2. Also, the RDG / More PPDU subfield contains information indicating to the non-STR non-AP MLD that it may transmit data to the AP MLD within the period T3' on Link 1 and Link 2 (i.e., Reverse Direction Grant: RDG). By indicating transmission permission within transmission period T1 in the RDG / More PPDU field of each PPDU transmitted by the AP MLD on Link 1 and Link 2, the STR non-AP MLD can again transmit another PPDU (i.e., uplink) within transmission period T1.

[0228] G-4.STR non-AP MLD1 control operation 21 shows an example of the operation of each logical entity in the communication unit 410 in the STR non-AP MLD1 to which PPDU #1-1 and PPDU #1-2 are notified in DL Transmission. The horizontal axis represents the time axis. In FIG. 21, multiple MPDUs in a PPDU are collectively referred to as a PSDU.

[0229] The communication unit 410 includes an individual control unit 1 for link 1 and an individual control unit 2 for link 2. The individual control units 1 and 2 are respectively configured with the logical entities of PHY Layer #1 and PHY Layer #2 that control the physical layers of link 1 and link 2, and MAC Lower Sublayer #1 and MAC Lower Sublayer #2 that control data processing of link 1 and link 2. The communication unit 410 also includes a Common Entity as a logical entity that controls data processing common to link 1 and link 2. Information is exchanged between layers and between layers and entities via SAP. The Common Entity calculates parameters to be applied to each MAC Lower Sublayer and PHY Layer in addition to parameters used by the common data processing unit 413 in the communication unit 410.

[0230] The PHY layer is composed of the antenna 440, the amplifier 417 in the communication unit 410, the wireless interface unit 416, the signal processing unit 415, and the individual control unit 414, and the MAC lower sublayer is composed of the individual data processing unit 414 in the communication unit 410 and the corresponding individual control unit in the communication control unit 411. However, the components of the PHY layer and the MAC lower sublayer are not limited to these.

[0231] In a normal communication operation, an Ack is sent from the STR non-AP MLD1 when each PSDU is received, but for the sake of convenience, this sequence of events is omitted from Fig. 21. That is, for example, during period T3, in addition to receiving a PSDU including a preamble and padding, an Ack is sent, but the description of the Ack transmission is omitted from Fig. 21.

[0232] The information communicated between the entities and the operation of each entity will be described below with reference to FIG.

[0233] First, data transmitted from AP MLD1 on link 1 is received by PHY Layer #1, demodulated, and the MPDU is passed to MAC Lower Sublayer #1. A similar operation is performed on link 2.

[0234] G-4-1. PHY Layer operation in link 1, information transmitted between PHY and MAC The arrow indicated by reference number 2101 in Figure 21 indicates the operation in which each MPDU is notified from PHY Layer #1 to MAC Lower Sublayer #1, in addition to control information (RXVECTOR) such as received power (RSSI), number of spatial streams, and PPDU format, based on the information indicated in the preamble.

[0235] PHY Layer #1 calculates T1, which is the demodulation operation period, based on the information indicated in the preamble and performs demodulation. After the demodulation operation is completed, PHY Layer #1 notifies MAC Lower Sublayer #1 that reception has been completed. The calculated T1 determines the time at which this PSDU reception completion notification is issued (the end of period T1 in the example shown in Figure 21). The arrow indicated by reference number 2101' in Figure 21 indicates the reception completion notification. This reception completion notification not only notifies the completion of reception, but also notifies the availability of the channel as determined by PHY Layer #1.

[0236] If the received signal is lost (carrier lost) within the period T1, PHY Layer #1 does not need to perform demodulation.

[0237] G-4-2. MAC Lower Sublayer Operation in Link 1, Information Transmitted Between MAC Lower and Common Entity After receiving the notification indicated by arrow 2101 from PHY Layer #1, MAC Lower Sublayer #1 analyzes the information included in the MPDU and notifies the common entity of the necessary information. The arrow indicated by reference number 2102 in FIG. 21 indicates this notification. For example, MAC Lower Sublayer #1 analyzes whether the Support Link Effort subfield in the MPDU indicates that AP MLD is attempting to acquire the transmission right on link 2, and notifies the common entity of this information. Similarly, MAC Lower Sublayer #1 may analyze whether the RDG / More PPDU subfield indicates that another transmission is permitted within the period T1, and notify the common entity of the information indicated in this field.

[0238] If the preamble contains Support Link Effort, the information in Support Link Effort may be analyzed in PHY Layer #1 and the information may be notified to the Common Entity via MAC Lower Sublayer #1.

[0239] G-4-3. PHY Layer operation in Link 2, information transmitted between PHY and MAC As described in section G-4-1 above, as indicated by the arrow with reference number 2103 in Figure 21, PHY Layer #2 notifies MAC Lower Sublayer #2 of each MPDU, in addition to control information (RXVECTOR) such as received power (RSSI), number of spatial streams, and PPDU format, based on the information indicated in the preamble.

[0240] Based on the information in the preamble, PHY Layer #2 calculates T3, which is the demodulation operation period, and performs demodulation. After the demodulation operation is completed, PHY Layer #2 notifies MAC Lower Sublayer #2 that reception has been completed. The calculated T3 determines the time at which this PSDU reception completion notification is issued (the end of period T3 in the example shown in Figure 21). The arrow indicated by reference number 2103' in Figure 21 indicates the reception completion notification. This reception completion notification not only notifies the MAC Lower Sublayer #2 that reception has been completed, but also notifies the MAC Lower Sublayer #2 of the availability of the channel determined by PHY Layer #2.

[0241] If the received signal is lost (carrier lost) within the period T3, PHY Layer #2 does not need to perform demodulation.

[0242] G-4-4. MAC Lower Sublayer Operation in Link 1, Information Transmitted Between MAC Lower and Common Entity

[0243] After receiving the notification indicated by arrow 2103 from PHY Layer #2, the MAC Lower Sublayer #2 analyzes the information included in the MPDU and notifies the Common Entity of the necessary information. The arrow indicated by reference number 2104 in FIG. 21 indicates this notification. For example, the MAC Lower Sublayer #2 analyzes the reception of a signal from the AP MLD and the information indicated in the ML-CAS including the Renewal Length (i.e., information indicating changes to the information indicated in the preamble notified on Link 1), and notifies the Common Entity of this information. For example, the MAC Lower Sublayer #2 analyzes whether the Basic Link Overwrite Flag subfield indicates that the preamble already transmitted on Link 1 and the information in the ML-CAS are to be overwritten, and notifies the Common Entity of this indication and the information to be changed. Similarly, the MAC Lower Sublayer #2 may analyze the RDG / More PPDU subfield to determine whether permission for another transmission within the period T1 is indicated, and notify the Common Entity of the information indicated in this field.

[0244] If the preamble contains Support Link Effort, the information in Support Link Effort may be analyzed in PHY Layer #1 and the information may be notified to the Common Entity via MAC Lower Sublayer #1.

[0245] G-4-5. Common Entity Operation Based on the notification from the MAC Lower Sublayer #2, the Common Entity notifies the PHY Layer #1 or MAC Lower Sublayer #1 of the link 1 included in the individual control unit 1 of at least information indicating the changed reception period (or reception end time), as indicated by the arrows of reference numbers 2105 and 2106 in Fig. 21. At this time, the Common Entity has been notified of the following information (1) and (2) from the PHY Layer of each link via the MAC Lower Sublayer:

[0246] (1) Information indicating that AP MLD is attempting to acquire transmission rights on Link 2 (2) Information indicating that the information notified by the preamble on Link 1 is to be changed

[0247] Note that, when it is indicated that the information in the ML-CAS notified via link 1 is to be changed, the Common Entity may also notify this information to the MAC Lower Sublayer #1. That is, when the RDG / More PPDU subfield in the ML-CAS notified via link 2 includes information indicating that transmission from STR non-AP MLD1 to AP MLD is permitted during the redundant period resulting from the shortened reception period, the Common Entity notifies the MAC Lower Sublayer #1 or PHY Layer #1 of this information. In Fig. 21, the Common Entity notifies the PHY Layer #1 via the MAC Lower Sublayer #1, but the Common Entity may also notify the PHY Layer #1 directly.

[0248] The common entity operates according to the processing procedure shown in Fig. 11. Here, a description of the operation of the common entity, that is, the flowchart shown in Fig. 11, will be omitted.

[0249] G-4-6. Notification of reception end time When the PHY Layer #1 is notified of a change in the reception period directly or indirectly by the Common Entity, it notifies the MAC Lower Sublayer #1 of the reception end time at the reception end time changed based on the notified information, as indicated by the arrow with reference number 2107 in Fig. 21. At this time, the Common Entity may notify the MAC Lower Sublayer #1 of the availability of the channel.

[0250] Furthermore, at the time when the PHY Layer #2 issues a notification of the end of reception of the PSDU transmitted on Link 2, as indicated by the arrow with reference number 2103' in FIG.

[0251] Here, the operation of the MAC Lower Sublayer #1 when a notification is sent to the PHY Layer #1 as indicated by the arrow 2106 in FIG. 21, and when a notification is sent from the PHY Layer #1 as indicated by the arrow 2107, will be explained in more detail.

[0252] The timing at which the MAC Lower Sublayer #1 notifies the PHY Layer #1 may be after all data (MPDUs) have been notified from the PHY Layer #1 to the MAC Sublayer #1.

[0253] For example, when an MPDU is notified from PHY Layer #1 to MAC Lower Sublayer #1 one octet (byte at a time), the post-change transmission data length of Link 1 can be estimated based on the information indicated by the Renewal Length notified from PHY Layer #2. Therefore, after PHY Layer #1 notifies MAC Lower Sublayer #1 of data with the number of octets equivalent to the estimated post-change transmission data length, MAC Lower Sublayer #1 may notify PHY Layer #1 of information indicating a request to terminate reception operation in PHY Layer #1. Upon receiving this request, PHY Layer #1 may notify MAC Lower Sublayer #1 of at least one of the reception end time and channel availability information.

[0254] G-4-7. Details of Common Entity and MAC Lower Sublayer Operation When the Common Entity receives notification of the reception end time from each PHY layer, it performs the following (1) to (3) as operations for the MAC Lower Sublayer indicated by the arrow with reference number 2108 in FIG.

[0255] (1) Generation of a response confirmation frame The Common Entity generates the information necessary to generate a response confirmation frame when an error is detected in the received MPDU. For example, if the received MPDU is managed by a certain number (such as a sequence number), it determines which MPDU number was received correctly or not, and passes the recorded information to each MAC Lower Sublayer.

[0256] (2) Generating information necessary for preamble generation The Common Entity passes control information required for non-STR non-AP MLD operation to the MAC Lower Sublayer or PHY Layer. This control information includes information indicating synchronous transmission over multiple links as non-STR non-AP MLD and information indicating the length of the PPDU generated by the PHY Layer.

[0257] (3) Delivering the MPDU to be transmitted to each MAC Lower Sublayer or each PHY Layer The Common Entity delivers MPDU information corresponding to the data to be transmitted to each MAC Lower Sublayer or each PHY Layer (corresponding to the operation indicated by arrow 2109 in FIG. 21). At this time, the length of the data to be transmitted is within a range not exceeding the period T1 in link 1, and is indicated as T2' in FIG. 21. In addition, the type of data may be restricted according to the information indicated in the AC Constraint notified immediately before from the AP MLD. For example, if transmission of only prioritized data such as voice communication is permitted, the Common Entity delivers only permitted data to the MAC Lower Sublayer or PHY Layer, and controls the PHY Layer to transmit only this data.

[0258] The above (1) to (3) may be partially performed by the MAC Lower Sublayer, in addition to the Common Entity, as necessary.

[0259] After each MAC lower sublayer passes information to each PHY layer, each PHY layer simultaneously transmits a PPDU. At this time, the acknowledgement frame and the MPDU representing the received data may be transmitted together in a single PPDU.

[0260] H. Summary As described in each embodiment, according to the present disclosure, when STR AP MLD is transmitting to non-AP MLD using link 1 and then transmitting using link 2, the STR AP MLD and non-AP MLD can each perform the following operations (1) to (3).

[0261] (1) By using link 2, STR AP MLD can realize the operation of notifying non-AP MLD of the shortened transmission period in link 1 using link 2. (2) When non-AP MLD receives signals transmitted asynchronously from AP MLD on multiple links, it can realize an internal operation in which the MAC layer of link 2 notifies the MAC layer of link 1 of the shortened transmission period ΔT on link 1. (3) The non-AP MLD can transmit to the STR AP MLD at least on link 1 during the shortened transmission period ΔT.

[0262] Therefore, according to the present disclosure, if the transmission period can be shortened by transmitting using link 2 while the STR AP MLD is transmitting to the non-AP MLD using link 1, it is possible to prevent delays in the transmission time of the Ack from the non-AP MLD and improve the transmission efficiency of the system. [Industrial Applicability]

[0263] Although the present disclosure has been described in detail above with reference to specific embodiments, it is obvious that those skilled in the art can make modifications or substitutions to the embodiments without departing from the spirit and scope of the present disclosure.

[0264] The present disclosure can be applied to a wireless network system that performs transmission using multiple links in accordance with, for example, IEEE 802.11 TG (Task Group) be, but of course, can also be similarly applied to various types of wireless network systems that perform transmission using multiple links in accordance with other communication standards.

[0265] In short, the present disclosure has been described in the form of examples, and the contents of the specification should not be interpreted as limiting. To determine the gist of the present disclosure, the claims should be taken into consideration.

[0266] The present disclosure may also be configured as follows.

[0267] (1) A communication device that performs wireless communication using multiple links, notifying information regarding a change in the transmission period of the first link due to transmission using a second link during the transmission period using the first link; Communication equipment.

[0268] (2) notifying the transmission partner of the information using the second link; The communication device according to (1) above.

[0269] (3) describing the information for each transmission unit constituting a data frame transmitted using the second link; A communication device according to either (1) or (2) above.

[0270] (4) for each transmission unit constituting a data frame transmitted using the first link, information indicating whether or not acquisition of a transmission right is being attempted on the second link is written; A communication device according to any one of (1) to (3) above.

[0271] (5) For each transmission unit constituting a data frame transmitted using the second link, information indicating whether or not at least information relating to the transmission period described in the frame transmitted over the first link has changed, and the information relating to the change in the transmission period over the first link are described. A communication device according to any one of (1) to (4) above.

[0272] (6) performing another transmission using at least one of the first link and the second link during the original transmission period on the first link; A communication device according to any one of (1) to (5) above.

[0273] (7) permitting a communication partner using the plurality of links to transmit using at least one of the first link and the second link during the original transmission period of the first link; The communication device according to (6) above.

[0274] (8) notifying other terminals of the release of the second link within the original transmission period of the first link; The communication device according to (6) above.

[0275] (9) The notification includes information for identifying a terminal that is prohibited from transmitting via the second link and information indicating a transmission prohibition period. The communication device according to (8) above.

[0276] (10) A communication method for wireless communication using a plurality of links, initiating transmission on a first link; During the transmission period using the first link, further starting transmission using a second link; notifying information about a change in a transmission period in the first link due to transmission using the second link; A communication method comprising:

[0277] (11) A communication device that performs wireless communication using a plurality of links, receiving information about a change in the transmission period of the first link due to transmission using the second link when data is received via the second link while data is being received via the first link; Communication equipment.

[0278] (12) receiving the information via the second link; The communication device according to (11) above.

[0279] (13) controlling a communication operation in the first link based on the information received in the second link; The communication device according to any one of (11) and (12) above.

[0280] (14) When receiving information on the first link indicating that the communication partner is attempting to acquire the transmission right on the second link, performing a reception process on the second link. A communication device according to any one of (11) to (13) above.

[0281] (15) receiving, via the second link, information indicating whether or not at least information relating to a transmission period described in a frame transmitted via the first link has changed, and the information relating to the change in the transmission period in the first link, and controlling a communication operation in the first link; A communication device according to any one of (11) to (14) above.

[0282] (16) A MAC layer processor for performing processing in the MAC layer for each link and a common data processor for performing data processing common to all links are provided, and the MAC layer processor for the second link notifies the MAC layer processor for the first link of the information received on the second link through the common data processor. A communication device according to any one of (11) to (15) above.

[0283] (17) The MAC layer processing unit of the second link receives, via the second link, information indicating whether or not at least information regarding a transmission period described in a frame transmitted via the first link has changed, and the information regarding the change in the transmission period in the first link, and notifies the MAC layer processing unit of the first link via the common data processing unit. The communication device according to (16) above.

[0284] (18) When the communication device can only perform either transmission or reception between the plurality of links, the communication device notifies a communication partner using the plurality of links of information regarding whether asynchronous transmission in which the transmission start times are not aligned between the plurality of links is possible. A communication device according to any one of (11) to (17) above.

[0285] (19) Notifying a communication partner using the plurality of links of information regarding a combination of links that cannot transmit and receive simultaneously but can receive asynchronous transmissions; A communication device according to any one of (11) to (18) above.

[0286] (20) A communication method for wireless communication using a plurality of links, receiving data on a first link; performing a receiving process on the second link when receiving information on the first link indicating that a communication partner is attempting to acquire a transmission right on the second link; receiving, when receiving data via the second link, information relating to a change in a transmission period of the first link due to transmission using the second link; controlling communication operations in the first link based on the information received in the second link; A communication method comprising: [Explanation of symbols]

[0287] 400... communication device, 410... communication unit, 411... communication control unit 412...communication storage unit, 413...common data processing unit 414... individual data processing unit, 415... signal processing unit 416...wireless interface unit, 417...amplifier unit, 420...control unit 430...storage unit, 440...antenna

Claims

1. A communication device that performs wireless communication using a plurality of links, notifying information regarding a change in the transmission period of the first link due to further transmission using the second link during the transmission period using the first link; Communication equipment.

2. notifying the information to a transmission partner using the second link; The communication device according to claim 1 .

3. the information is written for each transmission unit constituting a data frame transmitted using the second link; 2. The communication device according to claim 1.

4. and for each transmission unit constituting a data frame transmitted using the first link, information indicating whether or not acquisition of a transmission right is being attempted on the second link is written. The communication device according to claim 1 .

5. For each transmission unit constituting a data frame transmitted using the second link, information indicating whether or not at least information relating to a transmission period described in the frame transmitted over the first link has changed, and the information relating to a change in the transmission period over the first link are described. The communication device according to claim 1 .

6. performing another transmission using at least one of the first link and the second link during an original transmission period on the first link; The communication device according to claim 1 .

7. permitting a communication partner using the plurality of links to transmit using at least one of the first link and the second link during an original transmission period of the first link; The communication device according to claim 6.

8. notifying other terminals of the release of the second link within the original transmission period of the first link; The communication device according to claim 6.

9. the notification includes information for identifying a terminal that is prohibited from transmitting via the second link and information indicating a transmission prohibition period; The communication device according to claim 8.

10. A communication method for wireless communication using a plurality of links, comprising: initiating transmission on a first link; During the transmission period using the first link, further starting transmission using a second link; notifying information about a change in a transmission period in the first link due to transmission using the second link; A communication method comprising:

11. A communication device that performs wireless communication using a plurality of links, receiving information about a change in the transmission period of the first link due to transmission using the second link when data is received via the second link while data is being received via the first link; Communication equipment.

12. receiving the information over the second link; The communication device according to claim 11.

13. controlling a communication operation in the first link based on the information received in the second link; The communication device according to claim 11.

14. performing a receiving process on the second link when receiving information on the first link indicating that a communication partner is attempting to acquire a transmission right on the second link; The communication device according to claim 11.

15. receiving, via the second link, information indicating whether or not at least information relating to a transmission period described in a frame transmitted via the first link has changed, and the information relating to the change in the transmission period on the first link, and controlling a communication operation on the first link; The communication device according to claim 11.

16. a MAC layer processing unit that performs processing in the MAC layer for each link, and a common data processing unit that performs data processing common to all links, wherein the MAC layer processing unit of the second link notifies the MAC layer processing unit of the first link of the information received on the second link through the common data processing unit; The communication device according to claim 11.

17. a MAC layer processing unit of the second link receives, via the second link, information indicating whether or not at least information relating to a transmission period described in a frame transmitted via the first link has changed, and the information relating to a change in the transmission period in the first link, and notifies the MAC layer processing unit of the first link of the information via the common data processing unit; 17. The communication device of claim 16.

18. When the communication device can only perform either transmission or reception between the plurality of links, the communication device notifies a communication partner using the plurality of links of information regarding whether or not asynchronous transmission in which transmission start times are not aligned between the plurality of links is possible. The communication device according to claim 11.

19. notifying a communication partner using the plurality of links of information about a combination of links that does not allow simultaneous transmission and reception but allows reception of asynchronous transmission; The communication device according to claim 11.

20. A communication method for wireless communication using a plurality of links, comprising: receiving data on a first link; performing a receiving process on the second link when receiving information on the first link indicating that a communication partner is attempting to acquire a transmission right on the second link; receiving, when receiving data via the second link, information relating to a change in a transmission period of the first link due to transmission using the second link; controlling communication operations in the first link based on the information received in the second link; A communication method comprising:

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