Wireless communication device and wireless communication method, wireless communication system and wireless communication method

Abstract

This enables more efficient retransmission of undeliverable data in communications using multiple links. [Solution] The first wireless communication device starts transmitting a first A-MPDU to the second wireless communication device on the first link within a first transmission opportunity secured on the first link, starts transmitting a second A-MPDU to the second wireless communication device on the second link within a second transmission opportunity secured on the second link, adjusts the number of MPDUs included in the first A-MPDU so that the transmission of the first A-MPDU is completed within the first transmission opportunity and during the transmission of the second A-MPDU, and includes a control unit that performs control to acquire the first reception status in the second wireless communication device for at least one MPDU included in the first A-MPDU and at least one MPDU included in the second A-MPDU. This disclosure can be applied to communication devices that perform communication using multiple links.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication device and a wireless communication method, a wireless communication system and a wireless communication method, and particularly to a wireless communication device, a wireless communication method, a wireless communication system and a wireless communication method that can realize more suitable retransmission of undelivered data in communication using a plurality of links.

Background Art

[0002] Conventionally, a technique related to multi-user communication that can simultaneously transmit different data to a plurality of wireless terminals is known.

[0003] For example, Patent Document 1 discloses a communication method for receiving a data frame in which retransmission data and data addressed to other users are multiplexed when retransmission of data is required in multi-user communication.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in Patent Document 1, retransmission of undelivered data in communication using a plurality of links is not mentioned.

[0006] The present disclosure has been made in view of such a situation, and aims to realize more suitable retransmission of undelivered data in communication using a plurality of links.

Means for Solving the Problems

[0007] The first aspect of the present disclosure is a first wireless communication device, which includes a control unit that performs control to acquire a first reception status in the second wireless communication device for at least one MPDU in the first A-MPDU and at least one MPDU in the second A-MPDU, within a first transmission opportunity secured in the first link, and within a second transmission opportunity secured in the second link, and to perform control to acquire a first reception status in the second wireless communication device for at least one MPDU in the first A-MPDU and at least one MPDU in the second A-MPDU.

[0008] A wireless communication method according to the first aspect of this disclosure is a wireless communication method in which a first wireless communication device initiates the transmission of a first A-MPDU to a second wireless communication device on the first link within a first transmission opportunity secured on the first link, initiates the transmission of a second A-MPDU to a second wireless communication device on the second link within a second transmission opportunity secured on the second link, adjusts the number of MPDUs included in the first A-MPDU so that the transmission of the first A-MPDU is completed within the first transmission opportunity and during the transmission of the second A-MPDU, and acquires the reception status at the second wireless communication device for at least one MPDU included in the first A-MPDU and at least one MPDU included in the second A-MPDU.

[0009] A wireless communication system of a second aspect of the present disclosure includes a first wireless communication device having a first control unit and a second wireless communication device having a second control unit, wherein the first control unit initiates the transmission of a first A-MPDU to the second wireless communication device on the first link within a first transmission opportunity secured on the first link, initiates the transmission of a second A-MPDU to the second wireless communication device on the second link within a second transmission opportunity secured on the second link, performs control to adjust the number of MPDUs included in the first A-MPDU so that the transmission of the first A-MPDU is completed within the first transmission opportunity and during the transmission of the second A-MPDU, and the second control unit performs control to communicate the reception status in the second wireless communication device to the first wireless communication device for at least one MPDU included in the first A-MPDU and at least one MPDU included in the second A-MPDU.

[0010] A second aspect of the present disclosure is a wireless communication method comprising: a first wireless communication device initiating the transmission of a first A-MPDU to a second wireless communication device on the first link within a first transmission opportunity secured on the first link; initiating the transmission of a second A-MPDU to a second wireless communication device on the second link within a second transmission opportunity secured on the second link; adjusting the number of MPDUs included in the first A-MPDU so that the transmission of the first A-MPDU is completed within the first transmission opportunity and during the transmission of the second A-MPDU; and the second wireless communication device informing the first wireless communication device of the reception status at the second wireless communication device for at least one MPDU included in the first A-MPDU and at least one MPDU included in the second A-MPDU.

[0011] In a first aspect of this disclosure, the first wireless communication device initiates the transmission of a first A-MPDU to the second wireless communication device on the first link within a first transmission opportunity secured on the first link, and initiates the transmission of a second A-MPDU to the second wireless communication device on the second link within a second transmission opportunity secured on the second link, and the number of MPDUs included in the first A-MPDU is adjusted so that the transmission of the first A-MPDU is completed within the first transmission opportunity and during the transmission of the second A-MPDU, and the reception status at the second wireless communication device is obtained for at least one MPDU included in the first A-MPDU and at least one MPDU included in the second A-MPDU.

[0012] In a second aspect of the present disclosure, the first wireless communication device initiates the transmission of a first A-MPDU to the second wireless communication device on the first link within a first transmission opportunity secured on the first link, and initiates the transmission of a second A-MPDU to the second wireless communication device on the second link within a second transmission opportunity secured on the second link, and adjusts the number of MPDUs included in the first A-MPDU so that the transmission of the first A-MPDU is completed within the first transmission opportunity and during the transmission of the second A-MPDU, and the second wireless communication device transmits to the first wireless communication device the reception status at the second wireless communication device for at least one MPDU included in the first A-MPDU and at least one MPDU included in the second A-MPDU. [Brief explanation of the drawing]

[0013] [Figure 1] This diagram shows an example of a wireless LAN system configuration. [Figure 2] This diagram illustrates the available frequency bands and channel allocations. [Figure 3] This is a sequence diagram illustrating interference during data reception. [Figure 4]This is a sequence diagram for explaining interference during data reception. [Figure 5] This is a diagram showing an example of retransmission of missing data using multiple links. [Figure 6] This is a diagram showing an example of retransmission of missing data in the technology according to the present disclosure. [Figure 7] This is a diagram showing an example of retransmission of missing data in the technology according to the present disclosure. [Figure 8] This is a diagram showing an example of retransmission of missing data in the technology according to the present disclosure. [Figure 9] This is a diagram showing an example of retransmission of missing data in the technology according to the present disclosure. [Figure 10] This is a diagram showing an example of retransmission of missing data by the technology according to the present disclosure. [Figure 11] This is a sequence diagram for explaining retransmission of missing data. [Figure 12] This is a sequence diagram for explaining retransmission of missing data. [Figure 13] This is a diagram showing a configuration example of a frame transmitted and received during setup of Multi-Link Operation. [Figure 14] This is a diagram showing a configuration example of an A-MPDU frame. [Figure 15] This is a diagram showing a configuration example of a block ACK frame. [Figure 16] This is a diagram showing a configuration example of a block ACK frame. [Figure 17] This is a diagram showing a configuration example of a block ACK frame. [Figure 18] This is a diagram showing a configuration example of a block ACK frame. [Figure 19] This is a block diagram showing a configuration example of a communication device to which the technology according to the present disclosure is applied. [Figure 20] This is a block diagram showing a configuration example of a wireless communication module. [Figure 21] This is a flowchart showing the operation flow of a communication device during setup of Multi-Link Operation. [Figure 22]This flowchart shows the operation flow of the communication device during the setup of Multi-Link Operation. [Figure 23] This is a flowchart showing the operation flow of the transmitting communication device. [Figure 24] This is a flowchart showing the operation flow of the transmitting communication device. [Figure 25] This is a flowchart showing the operation flow of the receiving communication device. [Figure 26] This is a flowchart showing the operation flow of the receiving communication device. [Modes for carrying out the invention]

[0014] The following describes the forms for implementing this disclosure (hereinafter referred to as embodiments). The explanation will be given in the following order.

[0015] 1. Multi-Link Operation and its Challenges 2. Overview of the technology related to this disclosure 3. Embodiments of the Disclosure 3-1. Example of a Wireless LAN System Configuration 3-2. Interference during data reception 3-3. Example of resending undeliverable data 3-4. Example of Dataframe Structure 3-5. Example of a communication device configuration 3-6. Operation of the communication device 4. Summary

[0016] <1. Multi-Link Operation and its Challenges> (Regarding Multi-Link Operation) Conventionally, in wireless LAN systems, a frequency channel with an arbitrary bandwidth within a single frequency band is used for communication as a single communication link (hereinafter simply referred to as a link). Specifically, technologies standardized by IEEE 802.11b, 11g, and 11n are used for communication in the 2.4GHz frequency band, while technologies standardized by IEEE 802.11a, 11n, and 11ac are used for communication in the 5GHz frequency band.

[0017] Furthermore, in recent years, technologies standardized by IEEE 802.11ax have begun to utilize communication in the 6GHz frequency band.

[0018] These standards define the structure of the A-MPDU frame, which uses frame aggregation technology to combine multiple data (MAC layer protocol data units: MPDUs) into a single data frame.

[0019] Currently, the IEEE 802.11 Task Group (TG)be is investigating Multi-Link Operation (MLO), a technology that transmits and receives data using multiple links (frequency bands).

[0020] In this Multi-Link Operation, a method is being considered in which, when sending an acknowledgment (ACK) for data received on one link, the ACK also includes the reception status of data transmitted on other links.

[0021] On the other hand, conventionally, the method used to retransmit undelivered data in wireless LAN systems has been to receive an ACK (acknowledgment) returned after data transmission on each link and then retransmit the undelivered data on that link.

[0022] (Challenges of Multi-Link Operation) In conventional data transmission sequences, data transmitted via a particular link is assigned a sequence number for management purposes. Therefore, if data transmitted via another link is retransmitted, data outside the managed sequence number range will be retransmitted, disrupting the sequence number management system. In other words, unless sequence numbers across all links are managed centrally, it was impossible to identify which link's data had not been delivered.

[0023] Furthermore, since the sequence number space is composed of a predetermined information length (approximately 12 bits), it was not possible to manage sequence numbers beyond this range. In other words, if retransmitted data containing the sequence number of data transmitted on one link was transmitted on another link, the sequence numbers within the expected range would not match, and it would be impossible to identify the undelivered data and the data to be retransmitted on each link.

[0024] Furthermore, if retransmission was not completed by the predetermined retransmission timing, new data could not be sent. In other words, even when data transmitted over multiple links was managed collectively in Multi-Link Operation, the sequence number space could not be used until retransmission was complete, and new data could not be sent.

[0025] Furthermore, even when using a conventional virtual carrier sensing method based on network allocation vectors, once data transmission and ACK reception were completed, it was not possible to retransmit the undelivered data in a short period of time once data transmission from another communication device began.

[0026] Therefore, in wireless LAN systems, once an error occurs during data reception, it takes time to recover from the error. In particular, with the A-MPDU frame configuration, even if an error occurs in an intermediate MPDU, an ACK cannot be sent back until the last MPDU arrives, and the transmitting communication device could not immediately detect the occurrence of the error.

[0027] Furthermore, when identifying and resending undeliverable data, it was not possible to identify the undeliverable data until an ACK (acknowledgment) was received. Moreover, resending that undeliverable data was not possible until access rights were acquired on a newly available link. Therefore, when resending a large amount of data, it took time to confirm the receipt of all data. In particular, if there were errors in some of the data, a backoff time had to be set to send the data over a new link, potentially adding further delays.

[0028] In addition, when sending data with different access categories via each link, differences in the backoff time required for retransmission occurred, making it difficult to retransmit data quickly. In other words, if there was data with sequence numbers that were not retransmitted, the sequence number space could no longer be used, potentially preventing data transmission in priority access categories, such as applications where rapid transmission is required.

[0029] <2. Overview of the technology related to this disclosure> In the technology disclosed herein, when transmitting data using multiple links in Multi-Link Operation, undelivered data is retransmitted using an available link from among the predetermined links.

[0030] Specifically, when the transmitting communication device detects the existence of undelivered data, it retransmits the undelivered data using an available link. In this case, a specific link may be reserved in advance as an available link, or the undelivered data may be retransmitted using the link that becomes available at the latest.

[0031] Furthermore, the transmitting communication device, in order to understand the reception status of the receiving communication device, constructs A-MPDU frames with a shorter frame length using frame aggregation as needed, so that acknowledgment information (ACK) is returned promptly. This allows the transmitting communication device to detect the existence of undelivered data early. In other words, the transmitting communication device performs backoff control in advance on the link in use, and immediately after detecting the existence of undelivered data, retransmits that data.

[0032] Furthermore, the transmitting communication device reserves a transmission opportunity (TXOP) in advance to send data in order to retransmit undelivered data in a short time. When it detects the existence of undelivered data, it completes the retransmission of the undelivered data within the TXOP without going through a new backoff procedure.

[0033] On the other hand, the receiving communication device recognizes that data transmitted on another link is being retransmitted using a certain link, and combines the data received on the other link to construct the complete data. Here, acknowledgment of receipt is sequentially sent back to the transmitting communication device via a designated link, and the transmitting communication device retransmits the undelivered data using an available link.

[0034] Furthermore, when the receiving communication device constructs the acknowledgment information, it identifies data that has not been delivered on each link by including the sequence number of the received data in the block ACK frame, thereby identifying the data that needs to be retransmitted.

[0035] Furthermore, the receiving communication device notifies the transmitting communication device of available links for retransmission, allowing it to understand that undelivered data will be retransmitted on a designated link and centrally manage data received on multiple links. In addition, the receiving communication device includes the latest sequence number of the data received on each link as parameter information in the block ACK frame so that it can understand the error status of the received data.

[0036] This allows for early detection of undelivered data when multiple MPDUs are aggregated and transmitted via frame aggregation, and enables retransmission of the undelivered data using available links, thereby reducing the time required from the return of the ACK to the retransmission of the undelivered data.

[0037] Furthermore, since the latest sequence number of the data received at each link is included as parameter information in the block ACK frame, even if there is a time delay required for data decoding and the return of the block ACK frame, undelivered data will be reliably notified.

[0038] <3. Embodiments of this Disclosure> The following describes a wireless communication system according to an embodiment of this disclosure.

[0039] (3-1. Example of a Wireless LAN System Configuration) Figure 1 shows an example configuration of a wireless LAN system to which the technology described herein may be applied.

[0040] In the wireless LAN system shown in Figure 1, a first wireless network is established by connecting communication devices 11 and 12 to access point 10. Near the first wireless network, a second wireless network is established by access point 20 and communication device 21, and a third wireless network is established by access point 30 and communication device 31.

[0041] Access point 10 is located in a position where it can receive signals from access point 20, communication device 21, access point 30, and communication device 31. Communication device 11 is located in a position where it can receive signals from access point 20 and access point 30. Communication device 12 is located in a position where it can receive signals from communication device 21 and communication device 31.

[0042] In such a wireless LAN system, communication devices 11 and 12 that constitute the first network need to have fair access to each other, even if a second wireless network or a third wireless network exists.

[0043] Figure 2 illustrates the available frequency bands and channel allocations in a wireless communication system to which the technology described herein is applied.

[0044] As shown in Figure 2A, in the 2.4GHz band, when applying an OFDM wireless signal with a 20MHz bandwidth based on the IEEE802.11g standard, at least two channels are allocated.

[0045] Furthermore, as shown in Figure 2B, in the 5GHz band, when applying a 20MHz bandwidth OFDM wireless signal based on standards such as IEEE802.11a, many channels are allocated.

[0046] However, the operation of channel allocation in the 5GHz band varies from country to country and region to region, and each country's legal system stipulates the available frequency range, transmission power, and conditions for determining whether transmission is permitted.

[0047] For example, in Japan, eight channels from channel 36 to channel 64 (5GHz band A), shown in white in Figure B, and eleven channels from channel 100 to channel 140 (5GHz band B) are available for use.

[0048] In countries and regions other than Japan, channels 32, 68, 96, 144, and even channels 149 through 173 are available, as shown by the blacked-out or dashed lines in Figure B.

[0049] Furthermore, as shown in Figure 2C, more channels will be allocated in the 6GHz band, which is currently being standardized. Specifically, for example, 25 channels will be available in the UNII-5 band of 6GHz band A, 5 channels in the UNII-6 band of 6GHz band B, 17 channels in the UNII-7 band of 6GHz band C, and 12 channels in the UNII-8 band of 6GHz band D.

[0050] (3-2. Regarding interference during data reception) Interference during data reception will be explained with reference to Figures 3 and 4.

[0051] Figure 3 is a sequence diagram showing an example of a data-ACK collision in a conventional data transmission sequence.

[0052] In conventional communication methods, data transmission and ACK (acknowledgment) return are performed on the same channel. As a result, signals transmitted from neighboring networks can interfere with reception on one's own network, and signals transmitted from one's own network can interfere with reception on neighboring networks.

[0053] In the example shown in Figure 3, the self-network 50 is composed of a transmitting communication device 51 and a receiving communication device 52, and the adjacent network, the OBSS (Overlapping Basic Service Set) network 60, is composed of a transmitting communication device 61 and a receiving communication device 62.

[0054] For example, in the self-network 50, while the receiving communication device 52 is receiving data (A-MPDU) from the transmitting communication device 51, in the OBSS network 60, the receiving communication device 62 sends a CTS in response to the RTS from the transmitting communication device 61. At this time, the CTS from the receiving communication device 62 interferes with the data reception of the receiving communication device 52, and the receiving communication device 52 is unable to correctly receive and decode the data from the transmitting communication device 51.

[0055] Subsequently, in the OBSS network 60, while the receiving communication device 62 is receiving data (A-MPDU) from the transmitting communication device 61, in its own network 50, the receiving communication device 52 sends a block ACK back for the data from the transmitting communication device 51. At this time, the block ACK from the receiving communication device 52 interferes with the data reception of the receiving communication device 62, and the receiving communication device 62 is unable to correctly receive and decode the data from the transmitting communication device 61.

[0056] Furthermore, in the self-network 50, while the receiving communication device 52 is receiving data (retransmitted A-MPDU) retransmitted from the transmitting communication device 51, in the OBSS network 60, the receiving communication device 62 is sending a block ACK back for the data from the transmitting communication device 61. At this time, the block ACK from the receiving communication device 62 interferes with the data reception of the receiving communication device 52, and the receiving communication device 52 is unable to correctly receive and decode the retransmitted data from the transmitting communication device 51.

[0057] Furthermore, in the OBSS network 60, while the receiving communication device 62 is receiving data (retransmitted A-MPDU) retransmitted from the transmitting communication device 61, in its own network 50, the receiving communication device 52 sends a block ACK back for the retransmitted data from the transmitting communication device 51. At this time, the block ACK from the receiving communication device 52 interferes with the data reception of the receiving communication device 62, and the receiving communication device 62 is unable to correctly receive and decode the retransmitted data from the transmitting communication device 61.

[0058] Thus, the signals from the receiving communication device 52 of the self-network 50 and the signals from the receiving communication device 62 of the OBSS network 60 interfered with each other, causing a significant delay before all the data could be transmitted.

[0059] Figure 4 is a sequence diagram showing an example of a Multi-Link Operation using nearby frequency bands.

[0060] In multi-link operation, when using multiple links with similar frequency bands, signals transmitted back on one link may interfere with the reception of data transmitted on another link.

[0061] In the example shown in Figure 4, the transmitting communication device 71 uses the 5GHz band in Link 1 and the 6GHz band in Link 2. Similarly, the receiving communication device 72 uses the 5GHz band in Link 1 and the 6GHz band in Link 2.

[0062] For example, a transmitting communication device 71 transmits data (A-MPDU) asynchronously using Link 1 and Link 2. The receiving communication device 72 receives data via Link 2 earlier than it receives data via Link 1, and sends back a block ACK via Link 2. In this case, the block ACK on Link 2 may interfere with the reception of data on Link 1.

[0063] Subsequently, while the receiving communication device 72 is receiving the retransmitted data (retransmitted A-MPDU) on Link 2, it finishes receiving the data on Link 1 and sends back a block ACK using Link 1. At this time, the block ACK on Link 1 may interfere with the reception of the retransmitted data on Link 2.

[0064] Furthermore, while the receiving communication device 72 is receiving the retransmitted data (retransmitted A-MPDU) on Link 1, the reception of the retransmitted data on Link 2 is completed, and the device sends back a block ACK using Link 2. At this time, the block ACK on Link 2 may interfere with the reception of the retransmitted data on Link 1.

[0065] Thus, in Multi-Link Operation using similar frequency bands, the ACK sent back by the receiving communication device 72 becomes an interference signal, causing a significant delay before all data can be transmitted.

[0066] (3-3. Example of resending undeliverable data) Here, we will specifically illustrate examples of retransmission of undelivered data using conventional communication methods and examples of retransmission of undelivered data using the technology related to this disclosure.

[0067] Figure 5 shows an example of retransmitting undelivered data using multiple links in a conventional communication method.

[0068] In the example shown in Figure 5, data is transmitted from the first link (Link1) to the third link (Link3). Here, a data sequence number is managed for each link, an acknowledgment (ACK) is sent back, and any undelivered data is retransmitted for each link.

[0069] In Link 1, when the transmitting communication device acquires access rights through predetermined access control, it transmits data with sequence numbers 1 to 8 (Data1 to Data8), aggregated by frame aggregation, as an A-MPDU frame.

[0070] The receiving communication device acknowledges receipt of Data1 through Data8. In this diagram, Data3 and Data7, which were not received correctly due to errors, are shown in black. That is, after receiving the A-MPDU frame, the receiving communication device sends an acknowledgment (ACK) to the transmitting communication device, specifying the correctly received data (Data1, 2, 4 through 6, 8).

[0071] When the transmitting communication device becomes aware of the existence of undelivered data upon receiving an ACK from the receiving communication device, it retransmits that undelivered data (Data3 and Data7).

[0072] The receiving communication device, after acknowledging receipt of the undelivered data (Data3 and Data7), sends back an acknowledgment (ACK) to the transmitting communication device, specifying all the correctly received data (Data1 through Data8).

[0073] In Link 2, when the transmitting communication device acquires access rights through predetermined access control, it transmits the data with sequence numbers 9 to 16 (Data9 to Data16), which has been aggregated by frame aggregation, as an A-MPDU frame.

[0074] The receiving communication device acknowledges receipt of Data9 through Data16. In this diagram, Data10 and Data16, which were not received correctly due to errors, are shown in black. That is, after receiving the A-MPDU frame, the receiving communication device sends back acknowledgment information (ACK) to the transmitting communication device, specifying the correctly received data (Data9, 11 through 15).

[0075] When the transmitting communication device receives an ACK from the receiving communication device and becomes aware of the existence of undelivered data, it retransmits that undelivered data (Data10 and Data16).

[0076] After the receiving communication device confirms receipt of the undelivered data (Data10 and Data16), it sends back an acknowledgment (ACK) to the transmitting communication device specifying all the correctly received data (Data9 through Data16).

[0077] In Link 3, when the transmitting communication device acquires access rights through predetermined access control, it transmits the data with sequence numbers 17 to 24 (Data17 to Data24), which has been aggregated by frame aggregation, as an A-MPDU frame.

[0078] The receiving communication device acknowledges receipt of Data 17 through Data 24. In this diagram, Data 20, which was not received correctly due to an error, is shown in black. That is, after receiving the A-MPDU frame, the receiving communication device sends an acknowledgment (ACK) to the transmitting communication device, specifying the correctly received data (Data 17 through 19, 21 through 24).

[0079] When the transmitting communication device becomes aware of the existence of undelivered data upon receiving an ACK from the receiving communication device, it retransmits that undelivered data (Data20).

[0080] After the receiving communication device confirms receipt of the undelivered data (Data20), it sends back an acknowledgment (ACK) to the transmitting communication device, specifying all the correctly received data (Data17 to Data24).

[0081] As described above, in conventional communication methods, when retransmitting undelivered data using multiple links, the block ACK frame sent back for each link does not contain acknowledgment information (ACK) for data transmitted on other links. Therefore, it was necessary to retransmit the data independently for each link.

[0082] Therefore, the following describes an example of how the technology related to this disclosure can be used to resend undelivered data using an available link when undelivered data occurs at a predetermined link.

[0083] Figure 6 illustrates an example of retransmitting undeliverable data using the technology described herein.

[0084] In the example shown in Figure 6, data is transmitted from the first link (Link1) to the third link (Link3). Here, the sequence numbers of the data across all links are managed collectively, and a block ACK frame containing the data reception status on other links is returned as acknowledgment information (ACK), while any undelivered data is retransmitted using any link.

[0085] In the example shown in Figure 6, similar to the example in Figure 5, Data1 through Data8 are transmitted as A-MPDU frames using Link 1, Data9 through Data16 are transmitted using Link 2, and Data17 through Data24 are transmitted using Link 3.

[0086] On Link 1, after receiving A-MPDU frames (Data1 to Data8), the receiving communication device checks the data reception status on the other links (Link 2 and Link 3). Specifically, the receiving communication device checks the reception status of data with sequence numbers 1 to 8, 9 to 14, and 17 to 19 (Data1 to Data8, Data9 to Data14, Data17 to Data19), and sends acknowledgment information (ACK) including this reception status back to the transmitting communication device as a block ACK frame.

[0087] At this time, as shown in black in the diagram, the block ACK information indicates that Data3 and Data7 were not received correctly on Link1, and that Data10 was not received correctly on Link2. In other words, an ACK containing block ACK information describing the reception status of data, including data from other links, collected up to the time the A-MPDU frame was received on Link1 is sent back to the transmitting communication device. At this time, the receiving communication device may take some time to decode the received data, so it may take a certain amount of time for the block ACK information to be reflected.

[0088] When the transmitting communication device receives an ACK containing block ACK information that describes the undelivered data, it retransmits the undelivered data (Data3, Data7, Data10) using Link1, which has become available at that time.

[0089] In Link 2, after receiving A-MPDU frames (Data 9 to Data 16), the receiving communication device checks the data reception status on other links (Link 1 and Link 3). Specifically, the receiving communication device checks the reception status of data with sequence numbers 1 to 8, 9 to 16, and 17 to 21 (Data 1 to Data 8, Data 9 to Data 16, Data 17 to Data 21), and sends acknowledgment information (ACK) including this reception status back to the transmitting communication device as a block ACK frame.

[0090] At this point, as shown in black in the diagram, the block ACK information will indicate that Data16 was not received correctly on Link2 and Data20 was not received correctly on Link3. Since the retransmission of the previously undelivered data (Data3, Data7, Data10) has not yet begun, the block ACK information may also indicate that Data3, Data7, and Data10 were undelivered.

[0091] When the transmitting communication device receives an ACK containing block ACK information that lists the undelivered data, it retransmits the undelivered data (Data16, Data20) using Link2, which has become available at that time, excluding the undelivered data (Data3, Data7, Data10) that were previously decided to be retransmitted.

[0092] In Link 3, after receiving A-MPDU frames (Data 17 to Data 24), the receiving communication device checks the data reception status on the other links (Link 1 and Link 2). Specifically, the receiving communication device checks the reception status of all data with sequence numbers 1 to 24 (Data 1 to Data 24) and sends acknowledgment information (ACK) containing this reception status back to the transmitting communication device as a block ACK frame.

[0093] At this time, if the retransmitted data (Data3, Data7, Data10, Data16) has been received, this fact will also be recorded in the block ACK information.

[0094] At this point, only Data20 remains undelivered. However, since the transmitting communication device is retransmitting the undelivered data, including Data20, using Link2, it does not immediately begin retransmitting Data20 even after receiving an ACK containing block ACK information indicating that Data20 is undelivered. In other words, the transmitting communication device is configured to wait for an ACK in return for the retransmitted data via Link2 to determine whether further retransmission is necessary.

[0095] Then, the transmitting communication device receives an ACK (acknowledgment) for the retransmitted data, which includes block ACK information indicating that all data, including Data20, has been received, and this completes the series of operations.

[0096] Figure 7 illustrates another example of retransmitting undeliverable data in the technology relating to this disclosure.

[0097] In the example in Figure 7, by shortening the A-MPDU frame configuration on a link that starts transmitting data earlier, acknowledgment information (ACK) is returned on that link at an earlier time.

[0098] In other words, in the example shown in Figure 7, Data1 to Data5 are transmitted using Link1 as an A-MPDU frame, Data6 to Data15 are transmitted using Link2, and Data16 to Data24 are transmitted using Link3. However, other configurations are also possible.

[0099] On Link 1, after receiving A-MPDU frames (Data1 to Data5), the receiving communication device checks the data reception status on the other links (Link 2 and Link 3). Specifically, the receiving communication device checks the reception status of data with sequence numbers 1 to 5, 6 to 8, and 16 (Data1 to Data5, Data6 to Data8, Data16), and sends acknowledgment information (ACK) including this reception status back to the transmitting communication device as a block ACK frame.

[0100] At this time, as shown in black in the diagram, the block ACK information indicates that Data3 was not received correctly on Link1, Data7 on Link2, and Data16 on Link3. An ACK containing this block ACK information is then sent back to the transmitting communication device.

[0101] The transmitting communication device may be configured to retransmit the undelivered data (Data3, Data7, Data16) using Link1, which becomes available at that time, upon receiving an ACK containing block ACK information that describes the undelivered data.

[0102] The receiving communication device sends back an ACK for the retransmitted data (Data3, Data7, Data16) transmitted as an A-MPDU frame. This ACK includes block ACK information that describes the reception status of the data with sequence numbers 1 to 5, 6 to 13, and 16 to 21 (Data1 to Data5, Data6 to Data13, Data16 to Data21).

[0103] At this time, as shown in black in the diagram, the block ACK information indicates that Data10 was not received correctly on Link2, and that Data20 was not received correctly on Link3.

[0104] The transmitting communication device may be configured to retransmit the undelivered data (Data10, Data20) using Link1, which becomes available at that time, upon receiving an ACK containing block ACK information that describes the undelivered data.

[0105] In Link 2, after receiving A-MPDU frames (Data 6 to Data 15), the receiving communication device checks the data reception status on other links (Link 1 and Link 3). Specifically, the receiving communication device checks the reception status of data with sequence numbers 1 to 5, 6 to 15, and 16 to 23 (Data 1 to Data 5, Data 6 to Data 15, Data 16 to Data 23), and sends acknowledgment information (ACK) including this reception status back to the transmitting communication device as a block ACK frame.

[0106] At this point, the block ACK information will indicate that Data10 and Data20, including the retransmitted data, have not been received and are therefore undelivered.

[0107] In Link 3, after receiving A-MPDU frames (Data 16 to Data 24), the receiving communication device checks the data reception status on the other links (Link 1 and Link 2). Specifically, the receiving communication device checks the reception status of all data with sequence numbers 1 to 24 (Data 1 to Data 24) and sends acknowledgment information (ACK) containing this reception status back to the transmitting communication device as a block ACK frame.

[0108] At this point, the block ACK information will indicate that Data20, which was being retransmitted, has not yet been delivered.

[0109] Then, the transmitting communication device receives an ACK (acknowledgment) on Link 1 that includes block ACK information indicating that all data, including Data 20, has been received, and this completes the series of operations.

[0110] Figure 8 illustrates another example of retransmitting undeliverable data in the technology relating to this disclosure.

[0111] In the example shown in Figure 8, by setting the A-MPDU frame to a shorter configuration for all links, acknowledgment information (ACK) is returned earlier on all links, thereby facilitating the retransmission of undelivered data.

[0112] In other words, in the example shown in Figure 8, for example, Link1, which is the first to acquire access rights, sends an A-MPDU frame consisting of four MPDUs, while other links send an A-MPDU frame consisting of six MPDUs. However, other configurations are also possible.

[0113] On Link 1, after receiving A-MPDU frames (Data1 to Data4), the receiving communication device checks the data reception status on other links (Link 2). Specifically, the receiving communication device checks the reception status of data with sequence numbers 1 to 4, 5 to 7 (Data1 to Data4, Data5 to Data7), and sends acknowledgment information (ACK) containing this reception status back to the transmitting communication device as a block ACK frame.

[0114] At this time, as shown in black in the diagram, the block ACK information indicates that Data3 was not received correctly on Link1 and Data7 was not received correctly on Link2, and an ACK containing this block ACK information is sent back to the transmitting communication device.

[0115] When the transmitting communication device receives an ACK containing block ACK information that indicates undelivered data, it retransmits the undelivered data (Data3, Data7) using Link3, which is currently in a data transmission waiting state. Specifically, the transmitting communication device constructs an A-MPDU frame by combining the undelivered data (Data3, Data7) with the newly transmitted data (Data11 to Data14), and transmits it to the receiving communication device.

[0116] Link1, which becomes available after receiving an ACK, may be configured to subsequently transmit an A-MPDU frame consisting of newly transmitted data (Data15 to Data20).

[0117] In Link 2, after receiving A-MPDU frames (Data 5 to Data 10), the receiving communication device is aware of the data reception status on other links (Link 1). Specifically, the receiving communication device is aware of the reception status of data with sequence numbers 1 to 4, 5 to 10, and 15 (Data 1 to Data 4, Data 5 to Data 10, Data 15), and sends acknowledgment information (ACK) containing this reception status back to the transmitting communication device as a block ACK frame.

[0118] At this time, as shown in black in the diagram, Link1 records in its block ACK information that Data10 was not received correctly, and an ACK containing this block ACK information is sent back to the transmitting communication device.

[0119] When the transmitting communication device receives an ACK containing block ACK information that describes the undelivered data, it retransmits the undelivered data (Data10) using Link2, which has become available at that time. Specifically, the transmitting communication device may construct an A-MPDU frame by combining the undelivered data (Data10) with newly transmitted data (Data21 to Data24) and transmit it to the receiving communication device.

[0120] In Link 3, after receiving A-MPDU frames (Data3, Data7, Data11 to Data14), the receiving communication device checks the data reception status on other links (Link 1, Link 2). Specifically, the receiving communication device checks the reception status of data with sequence numbers 1 to 4, 5 to 10, 11 to 14, 15 to 19, 21, and 22 (Data1 to Data4, Data5 to Data10, Data11 to Data14, Data15 to Data19, Data21, Data22), and sends acknowledgment information (ACK) including this reception status back to the transmitting communication device as a block ACK frame.

[0121] At this time, as shown in black in the diagram, Link1 records in its block ACK information that Data16 was not received correctly, and an ACK containing this block ACK information is sent back to the transmitting communication device.

[0122] When the transmitting communication device receives an ACK containing block ACK information with undelivered data, it retransmits the undelivered data (Data16) using Link3, which has become available at that time. Specifically, the transmitting communication device may be configured to construct an A-MPDU frame containing the undelivered data (Data16) and transmit it to the receiving communication device.

[0123] Furthermore, in Link 1, after receiving the A-MPDU frame (Data 15 to Data 20), the receiving communication device sends back an ACK to the transmitting communication device that includes block ACK information indicating that Data 16 and Data 20 were not received correctly.

[0124] In this case, since Data16 is retransmitted using Link3, the transmitting communication device may be configured to retransmit only Data20 using Link1, which becomes available at that time, upon receiving an ACK containing block ACK information with undelivered data.

[0125] In Link 2, the transmitting communication device receives an ACK containing block ACK information indicating that all data (Data1 through Data24) has been received.

[0126] Then, although not shown in the diagram, the transmitting communication device receives an ACK (acknowledgment) for the retransmitted data on Link1 and Link3, which includes block ACK information indicating that all data, including Data16 and Data20, has been received, and this completes the series of operations.

[0127] Figure 9 illustrates another example of retransmission of undeliverable data in the technology relating to this disclosure.

[0128] In the example shown in Figure 9, a retransmission link for retransmitting undelivered data is pre-configured between the transmitting and receiving communication devices. This ensures that if undelivered data occurs, it is retransmitted using the retransmission link. Specifically, in the example shown in Figure 9, data is transmitted using Links 1 through 3, and if undelivered data occurs, it is retransmitted using Link 4, which is configured as a retransmission link. However, other configurations are also possible.

[0129] In the example shown in Figure 9, Data1 through Data8 are transmitted as A-MPDU frames using Link1, Data9 through Data16 are transmitted using Link2, and Data17 through Data24 are transmitted using Link3.

[0130] On Link 1, after receiving A-MPDU frames (Data1 to Data8), the receiving communication device checks the data reception status on the other links (Link 2 and Link 3). Specifically, the receiving communication device checks the reception status of data with sequence numbers 1 to 8, 9 to 14, and 17 to 20 (Data1 to Data8, Data9 to Data14, Data17 to Data20), and sends acknowledgment information (ACK) including this reception status back to the transmitting communication device as a block ACK frame.

[0131] At this time, as shown in black in the diagram, the block ACK information indicates that Data3 and Data7 were not received correctly in Link1, Data10 in Link2, and Data20 in Link3. An ACK containing this block ACK information is then sent back to the transmitting communication device.

[0132] The transmitting communication device is configured to retransmit the undelivered data (Data3, Data7, Data10, Data20) using Link4, which is set as the retransmission link, upon receiving an ACK containing block ACK information that indicates undelivered data.

[0133] In Link 4, prior to retransmitting undeliverable data, carrier sensing for access control may be performed in advance to ensure that Link 4 is not being used by other communication devices for a predetermined period of time.

[0134] Alternatively, a transmission opportunity (TXOP) of a predetermined duration may be set, and if the existence of undelivered data is detected, the undelivered data may be retransmitted sequentially.

[0135] In other words, the transmitting communication device can only determine that Data16 was not delivered via Link2 from the block ACK information included in the ACK sent via Link2. Therefore, when an ACK is returned via Link2, retransmission of the undelivered data (Data3, Data7, Data10, Data20) is initiated using Link4, but immediately afterward, the undelivered Data16 is added and retransmitted.

[0136] In the example shown in Figure 9, the transmitting communication device receives an ACK (acknowledgment) containing block ACK information indicating that all data has been received, as an ACK for the retransmitted data sent using Link 4, and this completes the series of operations.

[0137] Figure 10 illustrates another example of retransmission of undeliverable data in the technology relating to this disclosure.

[0138] In the example shown in Figure 10, a retransmission link for retransmitting undelivered data is pre-configured between the transmitting and receiving communication devices. This ensures that if undelivered data occurs, it is retransmitted using the retransmission link. Specifically, in the example shown in Figure 10, data is transmitted using Links 1 through 3, and if undelivered data occurs, it is retransmitted using Link 4, which is configured as the retransmission link. However, in the example shown in Figure 10, the receiving communication device notifies the transmitting communication device of undelivered data by appropriately returning an ACK on the retransmission link (Link 4), but other configurations are also possible.

[0139] In the example shown in Figure 10, Data1 through Data5 are transmitted as A-MPDU frames using Link1, Data6 through Data15 are transmitted using Link2, and Data16 through Data24 are transmitted using Link3.

[0140] On Link 1, after receiving A-MPDU frames (Data1 to Data5), the receiving communication device checks the data reception status on the other links (Link 2 and Link 3). Specifically, the receiving communication device checks the reception status of data with sequence numbers 1 to 5, 6 to 8, and 16 (Data1 to Data5, Data6 to Data8, Data16), and sends acknowledgment information (ACK) including this reception status back to the transmitting communication device as a block ACK frame.

[0141] At this time, as shown in black in the diagram, the block ACK information indicates that Data3 was not received correctly on Link1, Data7 on Link2, and Data16 on Link3. An ACK containing this block ACK information is then sent back to the transmitting communication device.

[0142] The transmitting communication device may be configured to retransmit the undelivered data (Data3, Data7, Data16) using Link4, which is set as the retransmission link, upon receiving an ACK containing block ACK information that describes the undelivered data.

[0143] In Link 4, after receiving the retransmitted data (Data3, Data7, Data16), the receiving communication device checks the data reception status on other links (Link 1 to Link 3). Specifically, the receiving communication device checks the reception status of data with sequence numbers 1 to 5, 6 to 13, and 16 to 21 (Data1 to Data5, Data6 to Data13, Data16 to 21), and sends acknowledgment information (ACK) including this reception status back to the transmitting communication device as a block ACK frame.

[0144] At this time, as shown in black in the diagram, the block ACK information indicates that Data10 was not received correctly in Link2 and that Data20 was not received correctly in Link3. An ACK containing this block ACK information is then sent back to the transmitting communication device.

[0145] The transmitting communication device may be configured to retransmit the undelivered data (Data10, Data20) using a retransmission link (Link4) upon receiving an ACK containing block ACK information that indicates undelivered data.

[0146] In addition, in Link2 and Link3, after receiving an A-MPDU frame, the receiving communication device sends back the latest ACK to the transmitting communication device, which includes block ACK information describing the data reception status at that time.

[0147] In the example shown in Figure 10, the transmitting communication device completes the series of operations when it receives an ACK containing block ACK information indicating that all data has been received, as an ACK for the retransmitted data sent using Link 4.

[0148] Here, we will explain the retransmission of undelivered data by referring to a sequence diagram between the transmitting and receiving communication devices.

[0149] Figure 11 is a sequence diagram illustrating the retransmission of undelivered data corresponding to the example in Figure 7 described above. Figure 11 shows the transmission and reception of data in Multi-Link Operation between the transmitting communication device 110 and the receiving communication device 120.

[0150] First, the transmitting communication device 110 and the receiving communication device 120 exchange setup data frames for setting up Multi-Link Operation using a specific link (Link1). This setup data frame contains parameter information, such as information about the multiple links used for sending and receiving data.

[0151] Specifically, the transmitting communication device 110 sends a Multi-link Setup Request as a setup data frame to the receiving communication device 120, and the receiving communication device 120 returns a Multi-link Setup Response.

[0152] This allows various parameter information to be set between the transmitting communication device 110 and the receiving communication device 120. For example, it is set that Link 2 and Link 3, in addition to Link 1, will be used for sending and receiving data.

[0153] As a result, the transmitting communication device 110 transmits data using multiple links (Link1 to Link3) and receives acknowledgment information (ACK) using these links. The receiving communication device 120 receives data using multiple links (Link1 to Link3) and sends back acknowledgment information (ACK) using these links.

[0154] Here, as described above, an A-MPDU frame, which is aggregated from multiple MPDUs, is transmitted using each link, with the specified data being combined into a single data frame through frame aggregation. On each link, data is transmitted when the transmission path becomes available after a predetermined backoff time has elapsed.

[0155] Specifically, the transmitting communication device 110 transmits data with sequence numbers 1 to 5 (data (1) to (5)) using Link 1, which becomes available first. Next, the transmitting communication device 110 transmits data with sequence numbers 6 to 15 (data (6) to (15)) using Link 2, which becomes available second. Finally, the transmitting communication device 110 transmits data with sequence numbers 16 to 24 (data (16) to (24)) using Link 3, which becomes available last.

[0156] In response, the receiving communication device 120 receives the A-MPDU frames transmitted using each link (Link1 to Link3) and collects error-free data by sequentially decoding the data contained therein. Data is received on each link at different times.

[0157] Furthermore, the receiving communication device 120, at the time after it has finished receiving A-MPDU frames on each link, sends back an acknowledgment (ACK) to the transmitting communication device 110, which includes block ACK information that identifies the MPDUs received up to that point.

[0158] In other words, Link1 sends back block ACK information (NACK(3,7,16)) that identifies data (3), (7), and (16) that did not arrive (shown by dashed lines in the diagram) by the time after the reception of data (1) through (5) is complete.

[0159] The transmitting communication device 110 is configured to retransmit the undelivered data (3), (7), and (16) using Link 1, which has become available, upon receiving a NACK (3, 7, 16) on Link 1.

[0160] The receiving communication device 120, after completing the reception of data (3), (7), and (16) on Link 1, sends back an acknowledgment (ACK) to the transmitting communication device 110 as acknowledgment information, which includes block ACK information that identifies the MPDUs received up to that point.

[0161] In other words, Link1 sends back block ACK information (NACK(10,20)) that identifies data (10) and (20) that did not arrive (shown by dashed lines in the diagram) by the time after the reception of data (3), (7), and (16) is complete.

[0162] The transmitting communication device 110 is configured to retransmit the undelivered data (10) and (20) using Link 1, which has become available, upon receiving a NACK (10, 20) on Link 1.

[0163] Furthermore, Link2 sends back block ACK information (NACK(20)) that identifies data (20) that has not been received (indicated by a dashed line in the diagram) by the time after the reception of data (6) through (15) is complete.

[0164] However, since the transmitting communication device 110 is in the process of retransmitting the data (20) using Link 1, it does not retransmit the data (20) again on Link 2, but instead waits for the ACK (block ACK information) to be returned afterward.

[0165] Then, in Link3, after receiving data (16) through (24), block ACK information (ACK(1-24)) is sent back, which allows all data (1) through (24) to be identified.

[0166] Similarly, on Link1, after receiving the undelivered data (10) and (20), block ACK information (ACK(1-24)) that identifies all data (1) through (24) is returned.

[0167] As described above, the example in Figure 7 shows a configuration in which undelivered data is retransmitted during Multi-Link Operation between the transmitting communication device 110 and the receiving communication device 120.

[0168] Although not shown in the diagram, in the example of Figure 8, the configuration may also be such that undelivered data is retransmitted in Multi-Link Operation between the transmitting communication device 110 and the receiving communication device 120.

[0169] Figure 12 is a sequence diagram illustrating the retransmission of undelivered data corresponding to the example in Figure 9 described above. Figure 12 also shows the transmission and reception of data in Multi-Link Operation between the transmitting communication device 110 and the receiving communication device 120.

[0170] First, the transmitting communication device 110 and the receiving communication device 120 exchange setup data frames for setting up Multi-Link Operation using a specific link (Link1). This setup data frame contains parameter information, such as information about the multiple links used for sending and receiving data.

[0171] Specifically, the transmitting communication device 110 sends a Multi-link Setup Request as a setup data frame to the receiving communication device 120, and the receiving communication device 120 returns a Multi-link Setup Response.

[0172] This allows various parameter information to be set between the transmitting communication device 110 and the receiving communication device 120. For example, it is set that Link 2 and Link 3 will be used in addition to Link 1 for sending and receiving data, and that Link 4 will be used as a retransmission link.

[0173] As a result, the transmitting communication device 110 transmits data using multiple links (Link1 to Link3) and receives acknowledgment information (ACK) using these links. The receiving communication device 120 receives data using multiple links (Link1 to Link3) and sends back acknowledgment information (ACK) using these links.

[0174] Furthermore, if undelivered data occurs, the transmitting communication device 110 will retransmit the undelivered data using the retransmission link (Link 4), and the receiving communication device 120 will receive the undelivered data using the retransmission link (Link 4).

[0175] Here too, the predetermined data is aggregated into a single data frame through frame aggregation, and as described above, an A-MPDU frame, which is an aggregate of multiple MPDUs, is transmitted using each link. On each link, data is transmitted when the transmission path becomes available after a predetermined backoff time has elapsed.

[0176] Specifically, the transmitting communication device 110 transmits data with sequence numbers 1 to 8 (data (1) to (8)) using Link 1, which becomes available first. Next, the transmitting communication device 110 transmits data with sequence numbers 9 to 16 (data (9) to (16)) using Link 2, which becomes available second. Finally, the transmitting communication device 110 transmits data with sequence numbers 17 to 24 (data (17) to (24)) using Link 3, which becomes available last.

[0177] In response, the receiving communication device 120 receives the A-MPDU frames transmitted using each link (Link1 to Link3) and collects error-free data by sequentially decoding the data contained therein. Data is received on each link at different times.

[0178] Furthermore, the receiving communication device 120, at the time after it has finished receiving A-MPDU frames on each link, sends back an acknowledgment (ACK) to the transmitting communication device 110, which includes block ACK information that identifies the MPDUs received up to that point.

[0179] In other words, Link1 sends back block ACK information (NACK(3,7,10,20)) that identifies data (3), (7), (10), and (20) that did not arrive (shown by dashed lines in the diagram) by the time after the reception of data (1) through (8) is complete.

[0180] The transmitting communication device 110 is configured to start retransmitting the undelivered data (3), (7), (10), and (20) using Link 4, which is set as the retransmission link, when it receives a NACK (3, 7, 10, 20) on Link 1.

[0181] On the other hand, Link2 sends back block ACK information (NACK(16)) that identifies data (16) which has not been received by the time after the reception of data (9) through (16) is complete (indicated by a dashed line in the figure). At this time, the block ACK information may also include a statement that data (10) and (20) are undelivered among the undelivered data being retransmitted using Link4.

[0182] The transmitting communication device 110 is configured to receive a NACK (16) on Link 2 and then use Link 4, which is set as the retransmission link, to retransmit data (16) in addition to the undelivered data (3), (7), (10), and (20).

[0183] Furthermore, in Link 3, after receiving data (17) through (24), block ACK information (ACK(1-24)) is returned that identifies all data (1) through (24). Of the undelivered data being retransmitted using Link 4, the block ACK information may also indicate that data (20) and (16) are undelivered.

[0184] Then, in Link 4, after receiving all retransmitted data (data (3), (7), (10), (20), (16)), block ACK information (ACK(1-24)) that identifies all data (1) through (24) is returned.

[0185] As described above, in the example shown in Figure 9, the configuration is such that undelivered data is retransmitted in Multi-Link Operation between the transmitting communication device 110 and the receiving communication device 120, but the configuration is not limited to this.

[0186] Although not shown in the diagram, in the example of Figure 10, undelivered data is retransmitted in a similar manner during Multi-Link Operation between the transmitting communication device 110 and the receiving communication device 120.

[0187] (3-4. Example of Dataframe Structure) Here, we will explain an example of the data (data frame) structure transmitted and received in a Multi-Link Operation between a transmitting communication device and a receiving communication device.

[0188] Figure 13 shows an example of the configuration of frames (setup data frames) that are transmitted and received during Multi-Link Operation setup.

[0189] The frame shown in Figure 13 is sent from the transmitting communication device as a Multi-link Setup Request and returned from the receiving communication device as a Multi-link Setup Response.

[0190] The setup data frame consists of a MAC header and multilink information elements.

[0191] The MAC header consists of Frame Control, which contains information such as the frame type; Duration, which indicates the frame's duration (the time required for transmission); Transmit Address, which indicates the source address; and Receive Address, which indicates the destination address.

[0192] For example, a multilink information element consists of Element ID (ML IE), Number of Multi Links, Ch.No., Reverse Links, Resend Links, and Parameter.

[0193] Element ID (ML IE) indicates the type of element. Number of Multi Links indicates the number of links that can be configured with multilinks. Ch.No. indicates the channel number of the link that can be configured with multilinks, and is set as many times as the Number of Multi Links. Reverse Links indicates the links configured as reverse links (return links) among the links configured with multilinks. Resend Links indicate the links configured as retransmission links among the links configured with multilinks.

[0194] The Parameter consists of parameter information related to data transmission and reception, such as Feedback Timing, ACK / NACK, Buffer Size, Bitmap Length, and Multi-Links Retransmit.

[0195] Feedback Timing indicates the timing of feedback in the reverse link. ACK / NACK indicates whether ACK or NACK information is sent back as acknowledgment. Buffer Size indicates the buffer capacity. Bitmap Length indicates the bitmap length of the ACK information. Multi-Links Retransmit contains information about data retransmission in Multi-Link Operation, including, for example, whether or not frame aggregation is performed.

[0196] For example, the Parameters in the Multi-link Setup Request sent from the transmitting communication device are set to desired values ​​as various parameter information, and the Parameters in the Multi-link Setup Response sent back from the receiving communication device are set to confirmed values ​​as various parameter information. As a result, the transmitting and receiving communication devices can perform the setup of Multi-Link Operation by exchanging the Multi-link Setup Request and Multi-link Setup Response.

[0197] Figure 14 shows an example of the configuration of an A-MPDU frame in the Multi-Link Operation of this disclosure.

[0198] The A-MPDU frame shown in Figure 14 is basically constructed in the same way as a conventional A-MPDU frame. That is, the A-MPDU frame in Figure 14 consists of a predetermined PLCH Header, a number of A-MPDU Subframes aggregated by frame aggregation, and EOF Padding.

[0199] An A-MPDU subframe consists of a predetermined delimiter, individual MPDUs, and padding. An MPDU consists of a predetermined MAC header, a Frame Body where the actual data is stored, and an FCS (Frame Check Sequence) that checks whether the frame is error-free.

[0200] In the A-MPDU frame of this disclosure, the Delimiter includes, for example, Quick, in addition to the conventional EOF, Length, and CRC. Quick is a bit used in Multi-Link Operation to identify data that was not delivered on another link and has been retransmitted. Quick may be set, for example, when an acknowledgment (ACK) is received from the receiving communication device.

[0201] In the example in Figure 14, Quick is assumed to be set within the Delimiter of all A-MPDU Subframes, but it may also be set within the PLCH Header or within the EHT Control in the MAC header of individual MPDUs.

[0202] Figure 15 shows an example of the configuration of a block ACK frame in the Multi-Link Operation of this disclosure.

[0203] The block ACK frame shown in Figure 15 is basically constructed in the same way as a conventional block ACK frame. That is, the block ACK frame in Figure 15 consists of a predetermined MAC Header, BA Control, and BA Information.

[0204] In the block ACK frame shown in Figure 15, the value "Multi-Link" is provided as the BA Control value to identify it as a block ACK frame in Multi-Link Operation.

[0205] Furthermore, in the block ACK frame shown in Figure 15, the BA Information includes the same Block Ack Starting Sequence Control and Block Ack Bitmap as before, as well as the Link Count. For example, the Link Count indicates the number of links in a Multi-Link Operation.

[0206] Furthermore, in the Multi-Link Operation described herein, since ACK information for multiple links is returned together, the Block Ack Bitmap is configured to have a longer information length than the information length of a conventional block ACK frame.

[0207] Figure 16 shows another example of the configuration of a block ACK frame in the Multi-Link Operation of this disclosure.

[0208] The block ACK frame shown in Figure 16 is also basically constructed in the same way as a conventional block ACK frame. That is, the block ACK frame in Figure 16 consists of a predetermined MAC Header, BA Control, and BA Information.

[0209] In the block ACK frame shown in Figure 16, the value "MLO" is provided as the BA Control value to identify that it is a block ACK frame for retransmitting undelivered data in Multi-Link Operation.

[0210] Furthermore, in the block ACK frame shown in Figure 16, the BA Information includes, in addition to the conventional Block Ack Starting Sequence Control and Block Ack Bitmap, Link Count and Link1 S / N to LinkN S / N. Link Count indicates the number of links in Multi-Link Operation. Link1 S / N to LinkN S / N indicates up to which sequence number data has been received on each link (Link1 to LinkN).

[0211] This type of block ACK frame configuration makes it possible to identify the range of undelivered data that the transmitting communication device cannot fully grasp due to differences in the processing capabilities of the receiving communication device. In other words, the transmitting communication device can accurately identify the undelivered data at the receiving communication device.

[0212] Figure 17 shows yet another example of the configuration of a block ACK frame in the Multi-Link Operation of this disclosure.

[0213] The block ACK frame shown in Figure 17 is also basically constructed in the same way as a conventional block ACK frame. That is, the block ACK frame in Figure 17 consists of a predetermined MAC Header, BA Control, and BA Information.

[0214] In the block ACK frame shown in Figure 17, the BA Control value is set to "Resend," which identifies it as a block ACK frame for retransmitting undelivered data in Multi-Link Operation.

[0215] Furthermore, in the block ACK frame shown in Figure 17, the BA Information includes, for example, Link Count, Link1 S / N to LinkN S / N, NACK Starting Sequence Control, and NACK Bitmap. Link Count indicates the number of links in Multi-Link Operation. Link1 S / N to LinkN S / N indicates up to which sequence number data has been received on each link (Link1 to LinkN).

[0216] Furthermore, the NACK Starting Sequence Control area replaces the conventional Block Ack Starting Sequence Control and is where the first sequence number of the data requesting retransmission is set. The NACK Bitmap replaces the conventional Block Ack Bitmap and indicates the sequence number of the data requesting retransmission.

[0217] Figure 18 shows yet another example of the configuration of a block ACK frame in the Multi-Link Operation of this disclosure.

[0218] The block ACK frame shown in Figure 18 is also basically constructed in the same way as a conventional block ACK frame. That is, the block ACK frame in Figure 18 consists of a predetermined MAC Header, BA Control, and BA Information.

[0219] In the block ACK frame shown in Figure 18, the value "ML NACK" is provided as the BA Control value to identify that it is a block ACK frame used to identify only information about undelivered data in Multi-Link Operation.

[0220] Furthermore, in the block ACK frame shown in Figure 18, the BA Information includes, for example, NACK Counts and NACK Sequence Number. NACK Counts indicate the number of data points that were not delivered in the Multi-Link Operation. NACK Sequence Number indicates the sequence number of the data points that were not delivered in the Multi-Link Operation, and is set to the number indicated by NACK Counts.

[0221] With this type of block ACK frame configuration, only the sequence number of the undelivered data is notified to the transmitting communication device, without the need to send redundant bitmap information back.

[0222] (3-5. Example of a communication device configuration) Figure 19 is a block diagram showing an example configuration of a communication device to which the technology described herein is applied.

[0223] The communication device 200 in Figure 19 can function as at least one of the transmitting and receiving communication devices described above, and can also function as an access point.

[0224] The communication device 200 is configured to include a network connection module 210, an information input module 220, an equipment control module 230, an information output module 240, and a wireless communication module 250.

[0225] The network connection module 210 is configured, for example, as a communication modem for connecting to a network such as the Internet when the communication device 200 functions as an access point.

[0226] The network connection module 210 does not necessarily have to be integrated into the communication device 200. The network connection module 210 may be configured, for example, as an ONU (Optical Network Unit) that connects to the Internet via a public communication line and an Internet service provider.

[0227] The information input module 220 is a module that inputs information representing user instructions (instruction information), and is composed of buttons, a keyboard, a touch panel, etc. The information input module 220 also does not necessarily need to be incorporated into the communication device 200.

[0228] The device control module 230 controls the communication device 200 to operate as a transmitting communication device, a receiving communication device, or an access point, based on the instruction information input to the information input module 220.

[0229] For example, when the communication device 200 is operated as a transmitting communication device, the device control module 230 supplies data for a predetermined application to the wireless communication module 250, causing it to transmit the data to the transmitting communication device. On the other hand, when the communication device 200 is operated as a receiving communication device, the device control module 230 causes the wireless communication module 250 to receive data from the transmitting communication device. The received data is supplied to the application executed by the device control module 230.

[0230] The information output module 240 is a module that outputs and presents to the user the operating status of the communication device 200 and information acquired via the network connection module 210. The information output module 240 consists of, for example, a display device such as an LED display, an LCD panel, or an organic EL display, and a speaker that outputs sound or music.

[0231] The wireless communication module 250 communicates wirelessly with other communication devices 200 and external devices.

[0232] Figure 20 is a block diagram showing an example configuration of the wireless communication module 250.

[0233] As shown in Figure 20, the wireless communication module 250 includes an interface (I / F) 301, a transmit buffer 302, a transmit sequence management unit 303, a transmit frame construction unit 304, a transmit processing unit 305, and a transmit / receive antenna 306. Furthermore, the wireless communication module 250 includes a receive processing unit 307, a receive frame analysis unit 308, a receive sequence management unit 309, a receive buffer 310, a multilink management unit 311, and an access control unit 312.

[0234] I / F301 is connected to other modules within the communication device 200 and exchanges various information and data. Specifically, I / F301 supplies data from other modules to the transmit buffer 302 and supplies data from the receive buffer 310 to other modules.

[0235] The transmit buffer 302 temporarily stores data from the I / F 301. The data stored in the transmit buffer 302 is sequentially supplied to the transmit sequence management unit 303.

[0236] The transmission sequence management unit 303 manages the sequence of data to be transmitted in order to transmit the data from the transmission buffer 302 via wireless communication. The data, to which a sequence number has been added, is sequentially supplied to the transmission frame construction unit 304.

[0237] The transmission frame construction unit 304 constructs an A-MPDU frame by aggregating data from the transmission sequence management unit 303 using frame aggregation, and also constructs a block ACK frame containing acknowledgment information (ACK). These constructed data frames are supplied to the transmission processing unit 305.

[0238] Functionally, a transmission processing unit 305 is provided for each of the multiple links. Based on the data frame from the transmission frame construction unit 304, the transmission processing unit 305 generates a transmission signal for each individual link and performs predetermined signal processing. The transmission signal for each link is transmitted to other communication devices 200 via the transmitting and receiving antenna 306.

[0239] Furthermore, transmission signals from other communication devices 200 are received by the receiving processing unit 307 as link-specific received signals via the transmitting / receiving antenna 306.

[0240] The receiving processing unit 307 is also functionally provided for each of the multiple links. The receiving processing unit 307 decodes the received signals for each link received via the transmitting and receiving antenna 306 and acquires data frames (A-MPDU frames and block ACK frames). These acquired data frames are supplied to the received frame analysis unit 308.

[0241] Thus, the transmission processing unit 305 and the reception processing unit 307, which are provided for each link, are used simultaneously whether the communication device 200 is operating as a transmitting communication device or as a receiving communication device.

[0242] The received frame analysis unit 308 analyzes the data frame from the received processing unit 307. For example, if an A-MPDU frame is received as a data frame, the received frame analysis unit 308 analyzes the A-MPDU frame to determine whether the individual data (MPDU) was received correctly. The received individual data is supplied to the received sequence management unit 309.

[0243] The receiving sequence management unit 309 manages the sequence number of the received data from the receiving frame analysis unit 308 and supplies that data to the receiving buffer 310. In particular, when the communication device 200 operates as a receiving communication device, the receiving sequence management unit 309 generates ACK information or NACK information based on the sequence number of the received data and supplies it to the multilink management unit 311.

[0244] The receive buffer 310 temporarily stores data from the receive sequence management unit 309. The data stored in the receive buffer 310 is output to other modules within the communication device 200 via the I / F 301 at a predetermined timing.

[0245] The multi-link management unit 311 manages various settings related to Multi-Link Operation. For example, the multi-link management unit 311 configures the multiple links used in Multi-Link Operation.

[0246] The access control unit 312 controls the transmission and reception of data for each of the multiple links configured by the multilink management unit 311. For example, the access control unit 312 controls the transmission processing unit 305 and the reception processing unit 307 provided for each link to set the backoff time for each link and to acquire the usage status of the transmission path.

[0247] For example, when the communication device 200 operates as a transmitting communication device, the access control unit 312 controls the transmission of data in parallel using multiple links, and the multilink management unit 311 sets up retransmission of undelivered data using available links if undelivered data occurs on a predetermined link.

[0248] The multilink management unit 311 identifies undelivered data that needs to be retransmitted based on acknowledgment (ACK) information from the receiving communication device, which is the destination of the data.

[0249] The multilink management unit 311 configures the retransmission of undelivered data using a link from among multiple links where data transmission has finished, or using a link that is in a data transmission waiting state. The multilink management unit 311 also configures the retransmission of undelivered data using a retransmission link from among multiple links.

[0250] The multilink management unit 311 controls the construction of data frames (A-MPDU frames) with adjusted data transmission amounts for at least one link used for data transmission, and also controls the construction of data frames that combine undelivered data with newly transmitted data. Furthermore, the multilink management unit 311 is configured to control the construction of data frames including undelivered data according to the timing of receiving acknowledgment information from the data destination and the data transmission waiting status, but other configurations are also possible.

[0251] The multilink management unit 311 pre-sets a transmission opportunity (TXOP) longer than the duration of the data frame for links that may be used to retransmit undelivered data. Furthermore, the multilink management unit 311 is configured to retransmit the second undelivered data immediately following the data frame if a second undelivered data occurs while a data frame containing the first undelivered data is being transmitted, but other configurations are also possible.

[0252] On the other hand, when the communication device 200 operates as a receiving communication device, the access control unit 312 controls the reception of data in parallel using multiple links, and the multilink management unit 311 sets acknowledgment information that includes information that can identify the data reception status on other links when sending acknowledgment information (ACK) on one link. The access control unit 312 then controls the sending of the acknowledgment information, and the multilink management unit 311 sets the reception of retransmission data corresponding to the acknowledgment information using one link.

[0253] The multilink management unit 311 sets receipt confirmation information, including the sequence number of the undelivered data, as information that can identify the data reception status on other links.

[0254] The multilink management unit 311 is configured to set up a retransmission link for receiving retransmitted data in addition to the link used for receiving parallel data, but other configurations are also acceptable.

[0255] The access control unit 312 is configured to control the return of acknowledgment information using a link accessible from the transmitting communication device, which is the source of the data, but other configurations are also possible.

[0256] The multilink management unit 311 manages both the reception of data using a predetermined link and the reception of retransmitted data. Specifically, while the multilink management unit 311 is receiving a data frame containing retransmitted data using a predetermined link, it does not request the transmission of retransmitted data to the data source (it does not set receipt confirmation information including the sequence number of the undelivered data).

[0257] Furthermore, after detecting the end of the received data frame (A-MPDU frame), the multilink management unit 311 determines whether it is necessary to output the received data or whether it is necessary to send back acknowledgment information.

[0258] (3-6. Operation of communication devices) The operation of the communication device 200 described above will be explained below.

[0259] (Operation during Multi-Link Operation setup) First, referring to the flowcharts in Figures 21 and 22, we will explain the operation flow of the communication device 200 (wireless communication module 250) during the setup of Multi-Link Operation.

[0260] In step S101, the multi-link management unit 311 acquires information about the links that can be configured in Multi-Link Operation.

[0261] In step S102, the multilink management unit 311 determines whether its own device (communication device 200) can operate as a transmitting communication device, in other words, whether it can transmit data. If it is determined that its own device can operate as a transmitting communication device, the process proceeds to step S103.

[0262] In step S103, the multi-link management unit 311 determines whether or not Multi-Link Operation is possible by its own device (communication device 200). If it is determined that Multi-Link Operation is possible, the process proceeds to step S104. On the other hand, if it is determined that Multi-Link Operation is not possible, step S104 is skipped.

[0263] In step S104, the multi-link management unit 311 sets candidate data transmission links from among the links that can be configured in Multi-Link Operation, which are links for transmitting data.

[0264] In step S105, the multilink management unit 311 determines whether it is necessary to set up a retransmission link for retransmitting undelivered data. If it is determined that setting up a retransmission link is necessary, the process proceeds to step S106. On the other hand, if it is determined that setting up a retransmission link is not necessary, step S106 is skipped.

[0265] In step S106, the multi-link management unit 311 selects candidate links for retransmission from among the links that can be configured in Multi-Link Operation.

[0266] In step S107, the multi-link management unit 311 determines whether the settings of the candidates for the data transmission link and the candidates for the retransmission link are completed. If it is determined that the settings of the candidates for each link are not completed, the process returns to step S103, and the subsequent processing is repeated. On the other hand, if it is determined that the settings of the candidates for each link are completed, the process proceeds to step S108.

[0267] In step S108, the access control unit 312 controls the transmission processing unit 305 to transmit a Multi-Link Setup Request to another communication device 200 serving as the receiving-side communication device using any one of the candidates for the data transmission link that have been set. The Multi-Link Setup Request is set with parameter information regarding each candidate for the link and the like.

[0268] In step S109, the access control unit 312 controls the reception processing unit 307 to determine whether a Multi-Link Setup Response from the receiving-side communication device has been received. If it is determined that the Multi-Link Setup Response has been received, the process proceeds to step S110.

[0269] In step S110, the access control unit 312 obtains the parameter information set in the Multi-Link Setup Response received by the reception processing unit 307 via the reception frame analysis unit 308.

[0270] In step S111, the multi-link management unit 311 sets the links (data transmission link and retransmission link) to be used for data transmission based on the parameter information obtained by the access control unit 312, and the operation at the time of setup is completed.

[0271] In this way, the multi-link management unit 311 of the transmission-side communication device sets the links to be used in the Multi-Link Operation through negotiation with the receiving-side communication device.

[0272] On the other hand, if it is determined in step S109 that the Multi-Link Setup Response has not been received, the process proceeds to step S112.

[0273] In step S112, after transmitting the Multi-Link Setup Request, it is determined whether a timeout has occurred according to whether the preset time has elapsed. If it is determined that the preset time has not elapsed and no timeout has occurred, the process returns to step S109 and waits for the reception of the Multi-Link Setup Response. On the other hand, if it is determined that the preset time has elapsed and a timeout has occurred, the process ends without completing the operation during setup.

[0274] Now, if it is determined in step S102 that the own device does not operate as the transmission-side communication device, that is, if the own device operates as the reception-side communication device, the process proceeds to step S113.

[0275] In step S113, the access control unit 312 determines whether the Multi-Link Setup Request from the transmission-side communication device has been received by controlling the reception processing unit 307. If it is determined that the Multi-Link Setup Request has not been received, the process returns to step S101. On the other hand, if it is determined that the Multi-Link Setup Request has been received, the process proceeds to step S114 (FIG. 22).

[0276] In step S114, the access control unit 312 acquires the parameter information set in the Multi-Link Setup Request received by the reception processing unit 307 via the reception frame analysis unit 308.

[0277] In step S115, the multilink management unit 311 obtains information on candidate data transmission links set by the transmitting communication device from the parameter information acquired by the access control unit 312.

[0278] In step S116, the multilink management unit 311 determines whether data can be received on the candidate data transmission link set by the transmitting communication device. Here, it is assumed that the candidate data transmission link is a link that can be set in Multi-Link Operation, for which information was acquired in step S101.

[0279] If it is determined that data can be received, the process proceeds to step S117. On the other hand, if it is determined that data cannot be received, step S117 is skipped.

[0280] In step S117, the multilink management unit 311 sets parameter information regarding data reception required for the data transmission links that have been determined to be capable of receiving data, based on the capacity of the receive buffer 310 and the usage status of those links.

[0281] In step S118, the multilink management unit 311 obtains information on candidate retransmission links set by the transmitting communication device from the parameter information acquired by the access control unit 312.

[0282] In step S119, the multi-link management unit 311 determines whether or not data can be received on the candidate retransmission link set by the transmitting communication device. Here again, it is assumed that the candidate retransmission link is a link that can be set in Multi-Link Operation, for which information was acquired in step S101.

[0283] If it is determined that data can be received, the process proceeds to step S120. On the other hand, if it is determined that data cannot be received, step S120 is skipped.

[0284] In step S120, the multilink management unit 311 sets parameter information regarding data reception required for the retransmission links that have been determined to be capable of receiving data, based on the capacity of the receive buffer 310 and the usage status of those links.

[0285] In step S121, the multi-link management unit 311 determines parameters related to the configuration of the block ACK frame, such as the method for describing block ACK information. In other words, parameters for the configuration of acknowledgment information (ACK) and data retransmission in Multi-Link Operation are set.

[0286] In step S122, the multi-link management unit 311 determines whether or not to perform a Multi-Link Operation. If it is determined that a Multi-Link Operation should be performed, the process proceeds to step S123.

[0287] In step S123, the access control unit 312 controls the transmission processing unit 305 to send a Multi-Link Setup Response to another communication device 200, which will be the transmitting communication device, using the link on which the Multi-Link Setup Request was received. The Multi-Link Setup Response contains parameter information and other details related to each candidate link.

[0288] In step S124, the multilink management unit 311 sets the links to be used for receiving data (data transmission link, retransmission link) based on the parameter information set by the access control unit 312, and the setup operation is completed.

[0289] In this way, the multi-link management unit 311 of the receiving-side communication device sets the links to be used in the Multi-Link Operation through negotiation with the transmitting-side communication device.

[0290] (Operation of the transmitting-side communication device) Referring to the flowcharts of FIGS. 23 and 24, the operation flow of the communication device 200 (wireless communication module 250) as the transmitting-side communication device will be described.

[0291] In step S201, the multi-link management unit 311 determines whether to perform data transmission. If it is determined to perform data transmission, the process proceeds to step S202.

[0292] In step S202, the multi-link management unit 311 acquires the number of available links for data transmission and the amount of data present in the transmission buffer 302.

[0293] In step S203, the multi-link management unit 311 determines whether it is possible to support the Multi-Link Operation based on the acquired number of available links and the amount of data in the transmission buffer 302. If it is determined that the Multi-Link Operation cannot be supported, the process returns to step S201. On the other hand, if it is determined that the Multi-Link Operation can be supported, the process proceeds to step S204.

[0294] In step S204, the access control unit 312 starts access control on the data transmission link by controlling the transmission processing unit 305.

[0295] In step S205, the multi-link management unit 311 calculates the transmission amount of the A-MPDU frame for each link.

[0296] In step S206, the multilink management unit 311 instructs the transmission frame construction unit 304 to construct A-MPDU frames for each link based on the transmission amount of A-MPDU frames calculated for each link. Here, the optimal number of MPDUs (number of transmitted data) is determined based on the transmission waiting time setting for each link and the congestion level of each link. Then, the number of MPDUs that is estimated to be the most efficient when all links are used is adjusted for each link.

[0297] In step S207, the access control unit 312 counts down the transmission waiting time for each link to determine whether or not any links have become ready to transmit. Step S207 is repeated until it is determined that there are links that have become ready to transmit. If it is determined that there are links that have become ready to transmit, the process proceeds to step S208.

[0298] In step S208, the access control unit 312 sets the transmission opportunity (TXOP) of the link that has become available for transmission as Duration. For example, a TXOP longer than the duration of the data frame is set. In this case, the TXOP may be set to a time that anticipates the retransmission of undelivered data.

[0299] In step S209, the access control unit 312 causes the transmission processing unit 305 to transmit the A-MPDU frame constructed within the set TXOP range.

[0300] In step S210, the multilink management unit 311 determines whether or not it is necessary to set up a retransmission link. If it is determined that it is necessary to set up a retransmission link, the process proceeds to step S211, and the multilink management unit 311 sets up the retransmission link. Here, the setting of the retransmission link is finalized to prevent the link that was set up as a retransmission link during the setup of Multi-Link Operation from being used unexpectedly when access control starts or when the link is in an idle state.

[0301] On the other hand, if it is determined that setting up a retransmission link is not necessary, step S211 is skipped and the process proceeds to step S212 (Figure 24). Also, if it is determined in step S201 that data transmission will not be performed, steps S202 to S211 are skipped and the process proceeds to step S212 (Figure 24).

[0302] In step S212, the access control unit 312 controls the reception processing unit 307 to determine whether or not it has received acknowledgment information from the receiving communication device. If it is determined that acknowledgment information (ACK) has not been received, the process returns to step S207 (Figure 23), and the transmission of A-MPDU frames on other links is repeated.

[0303] On the other hand, if it is determined that the receipt confirmation information has been received via the designated link, the process proceeds to step S213.

[0304] In step S213, the access control unit 312 obtains the ACK information (NACK information) set in the receipt confirmation information received by the reception processing unit 307 via the received frame analysis unit 308.

[0305] In step S214, the multilink management unit 311 determines whether or not there is any undelivered data that needs to be retransmitted to the receiving communication device, based on the ACK information (NACK information) obtained by the access control unit 312.

[0306] If it is determined that there is no undelivered data, that is, if all data has been successfully transmitted, the process ends. On the other hand, if it is determined that there is undelivered data, the process proceeds to step S215.

[0307] In step S215, the multilink management unit 311 identifies undelivered data on all links. Here, undelivered data is identified by determining the decryption status of the transmitted data on each link from the block ACK information included in the acknowledgment information.

[0308] In step S216, the multilink management unit 311 instructs the transmission frame construction unit 304 to construct an A-MPDU frame containing the identified undelivered data. In this way, an A-MPDU frame is constructed according to the timing of receiving acknowledgment information from the receiving communication device that is the destination of the data, and the data transmission waiting status. The A-MPDU frame constructed here may consist of a combination of undelivered data and newly transmitted data, or it may consist only of undelivered data.

[0309] In step S217, the access control unit 312 obtains the remaining time of the TXOP for the link that has finished transmitting data (the link that has received the acknowledgment information).

[0310] In step S218, the access control unit 312 determines whether or not there is no remaining time for the acquired TXOP. If it is determined that there is no remaining time, the process proceeds to step S219.

[0311] In step S219, the multilink management unit 311 determines whether there are any available links waiting to transmit. If it is determined that there are available links, the process proceeds to step S220, where the multilink management unit 311 selects the first available link from among the available links. Here, the first available link may be a link waiting to transmit, or a retransmission link may be selected.

[0312] On the other hand, if it is determined that there are no available links, the process returns to step S212 and enters a state of waiting for the next acknowledgment of receipt (ACK).

[0313] After the earliest available link is selected, in step S221, the access control unit 312 determines whether it is time to transmit on the selected link. Step S221 is repeated until it is determined that it is time to transmit. If it is determined that it is time to transmit, the process proceeds to step S222. Also, if it is determined in step S208 that there is time remaining, steps S219 to S221 are skipped and the process proceeds to step S222.

[0314] In step S222, the access control unit 312 instructs the transmission processing unit 305 to transmit the A-MPDU frame containing the undelivered data using a link that has been determined to have remaining time, or the earliest available free link. After that, the process returns to step S201.

[0315] In this way, the above process is repeated using all links configured in Multi-Link Operation until all data, including undelivered data, has been transmitted.

[0316] (Operation of the receiving communication device) Referring to the flowcharts in Figures 25 and 26, the operation flow of the communication device 200 (wireless communication module 250) as a receiving communication device will be explained. The processes in Figures 25 and 26 show the operation flow for one of multiple links, but in Multi-Link Operation, this process is executed in parallel for multiple links.

[0317] In step S301, the access control unit 312 determines, via the received frame analysis unit 308, whether or not it has received an A-MPDU frame addressed to itself. Step S301 is repeated until it is determined that an A-MPDU frame addressed to itself has been received. If it is determined that an A-MPDU frame addressed to itself has been received, the process proceeds to step S302.

[0318] In step S302, the multilink management unit 311 causes the received frame analysis unit 308 to acquire individual MPDUs based on the Length included in the Delimiter of the A-MPDU Subframe that constitutes the received A-MPDU frame.

[0319] In step S303, the multilink management unit 311 controls the receive sequence management unit 309 to determine whether the MPDU acquired by the received frame analysis unit 308 was received without errors. If it is determined that the MPDU was received without errors, the process proceeds to step S304.

[0320] In step S304, the multilink management unit 311 controls the receive sequence management unit 309 to store MPDUs that have been determined to have been received without errors in the receive buffer 310.

[0321] In step S305, the multilink management unit 311 stores the sequence number of the MPDU stored in the receive buffer 310 as ACK information in a storage area not shown.

[0322] On the other hand, if it is determined in step S303 that the data could not be received without errors, that is, if there was an error in the received MPDU, the process proceeds to step S306.

[0323] In step S306, the multilink management unit 311 stores the sequence number of the erroneous MPDU as NACK information in a storage area not shown.

[0324] After the MPDU sequence number is stored as ACK information or NACK information, in step S307, the multilink management unit 311 determines whether the received MPDU is the end of an A-MPDU frame. If it is determined that it is not the end of an A-MPDU frame, the process returns to step S302 and the subsequent processing is repeated. On the other hand, if it is determined that it is the end of an A-MPDU frame, the process proceeds to step S308.

[0325] In step S308, the multilink management unit 311 determines whether the data output conditions are met, such as whether it is time to output the data stored in the receive buffer 310. If it is determined that the data output conditions are met, the process proceeds to step S309.

[0326] In step S309, the multilink management unit 311 controls the I / F 301 to cause the I / F 301 to acquire data from the receive buffer 310.

[0327] In step S310, the multilink management unit 311 outputs the data acquired from the receive buffer 310 through the I / F 301. The output data is supplied to the application executed by the equipment control module 230.

[0328] On the other hand, if it is determined in step S308 that the data output conditions are not met, steps S309 and S310 are skipped.

[0329] In step S311, the multilink management unit 311 determines whether the conditions for returning the receipt confirmation information are met. Here, the determination of whether the conditions for returning the receipt confirmation information are met is made based on whether or not the receipt confirmation information needs to be returned and whether or not there is any undelivered data that requires retransmission.

[0330] For example, if an A-MPDU frame containing retransmitted undelivered data is being received via a designated link, it will be determined that the conditions for returning acknowledgment information are not met.

[0331] If it is determined that the conditions for returning the receipt confirmation information are not met, the process returns to step S302 and the subsequent processing is repeated. On the other hand, if it is determined that the conditions for returning the receipt confirmation information are met, the process proceeds to step S312 (Figure 26).

[0332] In step S312, the multilink management unit 311 acquires ACK information or NACK information stored in a memory area (not shown).

[0333] Here, not only ACK information (NACK information) for data on one link, but also ACK information (NACK information) including the data reception status on all other links is obtained.

[0334] In step S313, the multilink management unit 311 causes the transmission frame construction unit 304 to construct a block ACK frame containing the acquired ACK information or NACK information based on a pre-configured data format.

[0335] For example, when a block ACK frame is constructed as described with reference to Figures 16 and 17, the block ACK frame includes information that can identify the latest sequence number of the data received on each link. When a block ACK frame is constructed as described with reference to Figure 18, the block ACK frame includes NACK information that contains the sequence number of the undelivered data that needs to be retransmitted.

[0336] In step S314, the multi-link management unit 311 sets the link to be used to return the constructed block ACK frame. The link used to return the block ACK frame may be the same link that received the A-MPDU frame, or it may be the return link set as Reverse Links in the Multi-link Setup Response.

[0337] In step S315, the access control unit 312 determines whether the configured link has become available. Step S315 is repeated until it is determined that the configured link has become available. If it is determined that the configured link has become available, the process proceeds to step S316.

[0338] In step S316, the access control unit 312 causes the transmission processing unit 305 to send a block ACK frame using the now available link.

[0339] Subsequently, in step S317, the multilink management unit 311 determines whether or not all data (MPDU) has been received based on the MPDU sequence number managed by the reception sequence management unit 309.

[0340] If it is determined that not all data has been received, the process returns to step S301, and subsequent processing is performed on the A-MPDU frame containing the undelivered data to be retransmitted. On the other hand, if it is determined that all data has been received, the process terminates.

[0341] Through the above process, even if undelivered data occurs in a Multi-Link Operation using multiple links, the undelivered data will be retransmitted using an available link, thus enabling more efficient retransmission of undelivered data.

[0342] <4. Summary> According to the technology disclosed herein, undelivered data is retransmitted using a link other than the one used to transmit the data. Therefore, it is possible to retransmit undelivered data using the minimum necessary links while transmitting new data.

[0343] Specifically, when a transmitting communication device sends data using multiple links, undelivered data is retransmitted using the link where data transmission was completed earlier, allowing all data to be transmitted in a shorter time. Alternatively, when a transmitting communication device sends data using multiple links, undelivered data is retransmitted using a link that has not yet been used for data transmission or the link that becomes available at the latest, allowing data to be transmitted more efficiently in a shorter time.

[0344] Furthermore, since A-MPDU frames with shorter frame lengths can be formed by frame aggregation as needed, the transmitting communication device can receive acknowledgment information (ACK) in a shorter amount of time.

[0345] Furthermore, while data is being transmitted using one link, random access control backoff is performed on other links. As a result, immediately after a receiving error is detected by the receiving communication device, the transmitting communication device can efficiently retransmit the undeliverable data that resulted in the error.

[0346] Furthermore, when transmitting data using a particular link, a larger number of transmission opportunities (TXOPs) are allocated, and buffer time is included in the Duration, thus pre-allocating time for retransmitting undeliverable data using that link. In other words, by completing the retransmission within the Duration, backoff time is reduced, allowing the transmitting communication device to efficiently transmit data for applications such as RTA (Real-Time Application).

[0347] Furthermore, according to the technology relating to this disclosure, when receiving data using multiple links, information that can identify the latest sequence number of the data received on each link is included in the block ACK frame, so that the receiving communication device can more reliably notify the transmitting communication device of the sequence number of the undelivered data.

[0348] Furthermore, when receiving data via multiple links, the receiving communication device can notify the transmitting communication device of the sequence number of the erroneous data among the undelivered data by sending back a block ACK frame containing NACK information. By clearly identifying the sequence number of the erroneous data, it is possible to prevent unsent data or data that has not been decrypted incomplete, which are not represented by conventional bitmap format information, from being retransmitted multiple times.

[0349] Furthermore, the effects described herein are merely illustrative and not limiting; other effects may also occur.

[0350] Furthermore, embodiments applying the technology described herein are not limited to those described above, and various modifications are possible without departing from the gist of the technology described herein.

[0351] Furthermore, this disclosure can take the following form. (1) An access control unit that controls the transmission of data in parallel using multiple links in a wireless network, If undelivered data occurs on a predetermined link, a multilink management unit sets up a retransmission of the undelivered data using an available link. A communication device equipped with the following features. (2) The multilink management unit identifies the undelivered data that needs to be resent based on the receipt confirmation information from the data recipient. (1) The communication device described above. (3) The multilink management unit sets the retransmission of the undelivered data using the link from which the transmission of the data has ended among the multiple links. (1) or (2) the communication device described above. (4) The multilink management unit sets the retransmission of the undelivered data using the link that is in a data transmission waiting state among the multiple links. (1) or (2) the communication device described above. (5) The multilink management unit sets the retransmission of the undelivered data using the retransmission link among the multiple links for the purpose of retransmitting the undelivered data. (1) or (2) the communication device described above. (6) The multilink management unit controls the construction of a data frame with an adjusted number of data points for at least one of the links used to transmit the data. A communication device as described in any of (1) to (5). (7) The multilink management unit controls the construction of a data frame combining the undelivered data and the newly transmitted data for at least one of the links used to transmit the data. A communication device as described in any of (1) to (5). (8) The multilink management unit controls the construction of a data frame including the undelivered data, according to the timing of receiving confirmation information from the data destination and the data transmission waiting status. A communication device as described in any of (1) to (7). (9) The multilink management unit pre-sets transmission opportunities longer than the duration of the data frame for the link that can be used to retransmit the undelivered data. A communication device as described in any of (1) through (8). (10) If a second set of undelivered data occurs while a data frame containing the first set of undelivered data is being transmitted, the multilink management unit will set the retransmission of the second set of undelivered data immediately following the transmission of the first data frame. A communication device as described in any of (1) to (9). (11) The communication device Controlling parallel data transmission using multiple links in a wireless network, If undelivered data occurs on a predetermined link, the system will resend the undelivered data using an available link. Communication method. (12) An access control unit that controls the reception of data in parallel using multiple links in a wireless network, When sending confirmation of receipt information in one link, a multilink management unit sets the confirmation of receipt information which includes information that can identify the status of the receipt of the data in other links. Equipped with, The access control unit controls the return of the receipt confirmation information, The multilink management unit sets up the reception of retransmission data corresponding to the receipt confirmation information using the link 1. Communication device. (13) The multilink management unit sets the receipt confirmation information, which includes the sequence number of the undelivered data, as information that can identify the status of data reception on the other links. (12) The communication device described above. (14) The multilink management unit sets up a retransmission link for receiving the retransmitted data, in addition to the link used for receiving the parallel data. (12) or (13) the communication device described above. (15) The access control unit controls the return of the acknowledgment information using the link accessible to the data sender. A communication device as described in any of (12) to (14). (16) The multilink management unit manages both the reception of the data using the predetermined link and the reception of the retransmitted data. A communication device as described in any of (12) to (15). (17) The multilink management unit does not request the transmission of the retransmission data to the data source while it is receiving a data frame containing the retransmission data using a predetermined link. A communication device as described in any of (12) to (16). (18) After detecting the end of the received data frame, the multilink management unit determines whether or not it is necessary to output the received data. A communication device as described in any of (12) to (17). (19) After detecting the end of the received data frame, the multilink management unit determines whether or not to send the receipt confirmation information back. A communication device as described in any of (12) to (18). (20) The communication device Controlling the reception of parallel data using multiple links in a wireless network. When sending confirmation of receipt information via link 1, the confirmation of receipt information includes information that can identify the status of data reception via other links, Control the return of the aforementioned receipt confirmation information, Set the link to receive the retransmitted data. Communication method. [Explanation of symbols]

[0352] 200 Communication device, 250 Wireless communication module, 301 I / F, 302 Transmit buffer, 303 Transmit sequence management unit, 304 Transmit frame construction unit, 305 Transmit processing unit, 306 Transmit / receive antenna, 307 Receiving processing unit, 308 Receiving frame analysis unit, 309 Receiving sequence management unit, 310 Receiving buffer, 311 Multilink management unit, 312 Access control unit

Claims

1. A first wireless communication device, Within the first transmission opportunity secured on the first link, the transmission of the first A-MPDU to the second wireless communication device on the first link is initiated. Within the second transmission opportunity secured on the second link, the transmission of the second A-MPDU to the second wireless communication device on the second link is initiated. The number of MPDUs included in the first A-MPDU is adjusted so that the transmission of the first A-MPDU is completed within the first transmission opportunity and during the transmission of the second A-MPDU. A control unit that performs control to acquire the first reception status in the second wireless communication device for at least one MPDU included in the first A-MPDU and at least one MPDU included in the second A-MPDU. A wireless communication device equipped with the following features.

2. The control unit performs control to start the transmission of the second A-MPDU while the first A-MPDU is being transmitted. The wireless communication device according to claim 1.

3. The control unit performs control to acquire the first reception status while the second A-MPDU is transmitting. The wireless communication device according to claim 1.

4. The control unit acquires the first reception status from the second wireless communication device via the first link. The wireless communication device according to claim 1.

5. The control unit performs control to retransmit at least one undelivered MPDU included in the first A-MPDU or the second A-MPDU based on the first reception status. The wireless communication device according to claim 1.

6. The control unit performs control to retransmit the at least one undelivered MPDU within the first transmission opportunity. The wireless communication device according to claim 5.

7. The control unit performs control to retransmit the at least one undelivered MPDU through the first link. The wireless communication device according to claim 6.

8. The control unit performs control to retransmit the at least one undelivered MPDU through the third link. The wireless communication device according to claim 6.

9. The control unit performs control to initiate retransmission of the at least one undelivered MPDU while the second A-MPDU is being transmitted. The wireless communication device according to claim 6.

10. The control unit performs control to transmit a third A-MPDU to the second wireless communication device, which includes an MPDU not included in either the first A-MPDU or the second A-MPDU, and the at least one undelivered MPDU. The wireless communication device according to claim 5.

11. The control unit performs control to start the transmission of the third A-MPDU while the second A-MPDU is being transmitted. The wireless communication device according to claim 10.

12. The control unit performs control to transmit the third A-MPDU through the first or second link that has become available. The wireless communication device according to claim 10.

13. The control unit performs control to transmit the third A-MPDU through the third link. The wireless communication device according to claim 10.

14. The control unit, while the third A-MPDU is transmitting, performs control to acquire the second reception status of the second wireless communication device for at least one MPDU included in the first A-MPDU or the second A-MPDU. The wireless communication device according to claim 10.

15. The control unit acquires the second reception status from the second wireless communication device via the second link. The wireless communication device according to claim 14.

16. The first and second links are in different frequency bands among the 2.4 GHz, 5 GHz, and 6 GHz bands. The wireless communication device according to claim 1.

17. The device further comprises an antenna for communicating with the second wireless communication device. The wireless communication device according to claim 1.

18. The first wireless communication device is Within the first transmission opportunity secured on the first link, the transmission of the first A-MPDU to the second wireless communication device on the first link is initiated. Within the second transmission opportunity secured on the second link, the transmission of the second A-MPDU to the second wireless communication device on the second link is initiated. The number of MPDUs included in the first A-MPDU is adjusted so that the transmission of the first A-MPDU is completed within the first transmission opportunity and during the transmission of the second A-MPDU. The reception status of the second wireless communication device is acquired for at least one MPDU included in the first A-MPDU and at least one MPDU included in the second A-MPDU. Wireless communication method.

19. A first wireless communication device comprising a first control unit, A second wireless communication device comprising a second control unit and Includes, The first control unit is, Within the first transmission opportunity secured on the first link, the transmission of the first A-MPDU to the second wireless communication device on the first link is initiated. Within the second transmission opportunity secured on the second link, the transmission of the second A-MPDU to the second wireless communication device on the second link is initiated. Control is performed to adjust the number of MPDUs included in the first A-MPDU so that the transmission of the first A-MPDU is completed within the first transmission opportunity and during the transmission of the second A-MPDU. The second control unit performs control to transmit the reception status of the second wireless communication device to the first wireless communication device for at least one MPDU included in the first A-MPDU and at least one MPDU included in the second A-MPDU. Wireless communication system.

20. The first wireless communication device is Within the first transmission opportunity secured on the first link, the transmission of the first A-MPDU to the second wireless communication device on the first link is initiated. Within the second transmission opportunity secured on the second link, the transmission of the second A-MPDU to the second wireless communication device on the second link is initiated. The number of MPDUs included in the first A-MPDU is adjusted so that the transmission of the first A-MPDU is completed within the first transmission opportunity and during the transmission of the second A-MPDU. The second wireless communication device transmits to the first wireless communication device the reception status in the second wireless communication device with respect to at least one MPDU included in the first A-MPDU and at least one MPDU included in the second A-MPDU. Wireless communication method.

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