Method and apparatus for recovering error in wireless LAN

Abstract

Disclosed are a method and an apparatus for recovering an error in a wireless LAN. The method performed by the STA MLD comprises the steps of: transmitting, by a first STA linked with the STA MLD, a first frame on a first link to a first AP linked with the AP MLD; transmitting, by a second STA linked with the STA MLD, a second frame on a second link to a second AP linked with the AP MLD; if the transmission of the first frame fails, retransmitting, by the first STA, the first frame to the first AP on the first link; and receiving a first receive response frame of the first frame from the first AP on the first link.

Description

Technical Field

[0001] The present invention relates to a wireless local area network (LAN) communication technology, and more particularly, to a technology for recovering frame errors in communication of a non-simultaneous transmit and receive (NSTR) device. Background Art

[0002] Recently, with the popularity of mobile devices, wireless local area network technology that can provide fast wireless communication services to mobile devices has become a focus. Wireless local area network technology can be a technology that supports mobile devices (e.g., smart phones, smart tablets, laptops, portable multimedia players, embedded devices, etc.) to access the Internet in a wireless manner based on wireless communication technology.

[0003] The standards using wireless LAN technology are mainly developed as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. As the above wireless LAN technology has been developed and widely adopted, applications using wireless LAN technology have been diversified, and there has been a demand for wireless LAN technology supporting higher throughput.

[0004] With the emergence of applications that require higher throughput and applications that require real-time transmission, the IEEE 802.11be standard is being developed, which is an extreme high throughput (EHT) wireless LAN technology. The goal of the IEEE 802.11be standard may be to support a high throughput of 30 Gbps. The IEEE 802.11be standard may support technologies for reducing transmission delays. In addition, the IEEE 802.11be standard may support a more extended frequency bandwidth (e.g., 320 MHz bandwidth), multi-link transmission and aggregation operations including multi-band operations, multi-access point (AP) transmission operations, and / or efficient retransmission operations (e.g., hybrid automatic repeat request (HARQ) operations).

[0005] In a wireless local area network, improvements to the carrier sensing multiple access with collision avoidance (CSMA / CA) scheme may be necessary for low-power operation. When utilizing the CSMA / CA scheme, a communication node (e.g., AP, station (STA), multi-link device (MLD)) may perform a channel access operation to send data. If the result of the channel access operation indicates an idle state, the communication node may transmit data. Therefore, the communication node may compete with other communication nodes to transmit data. Since time is consumed due to competition, data may not be transmitted in a timely manner. In other words, the requirements for low-latency communication may not be met.

[0006] On the other hand, the technical writing in the background art of the present invention is to enhance the understanding of the background art of the present invention, and may include contents unknown to those of ordinary skill in the art to which the present invention belongs. Summary of the invention

[0007] Technical issues

[0008] The present invention is directed to providing a method and apparatus for recovering frame errors in communications of a non-simultaneous transmit and receive (NSTR) device.

[0009] Technical Solution

[0010] According to an exemplary embodiment of the present invention, a method of a station (STA) multi-link device (MLD) for achieving the above-mentioned purpose may include: enabling a first STA associated with the STA MLD to send a first frame to a first access point (AP) associated with the AP MLD on a first link; enabling a second STA associated with the STA MLD to send a second frame to a second AP associated with the APMLD on a second link; in response to a transmission failure of the first frame, enabling the first STA to retransmit the first frame to the first AP on the first link; and receiving a first reception response frame of the first frame from the first AP on the first link, wherein the first reception response frame includes first reception status information of the first frame and second reception status information of the second frame.

[0011] The STA MLD may be a non-simultaneous transmission and reception (NSTR) STA MLD that does not support simultaneous transmission and reception (STR) operation, and when retransmission of the first frame interferes with reception of a second reception response frame of the second frame, second reception status information may be included in the first reception response frame.

[0012] The first reception response frame may include a first medium access control (MAC) layer protocol data unit (MPDU) including first reception status information and a second MPDU including second reception status information.

[0013] The transmission of the first frame and the transmission of the second frame may be performed simultaneously, and the transmission end time of the first frame may be earlier than the transmission end time of the second frame.

[0014] Transmission of the first frame may be performed in a first transmission opportunity (TXOP) configured by the first STA, and transmission of the second frame may be performed in a second TXOP configured by the second STA.

[0015] The method may further include enabling the second STA to receive a second reception response frame of the second frame from the second AP on the second link after the retransmission operation of the first frame is completed on the first link.

[0016] According to an exemplary embodiment of the present invention, a method of an access point (AP) MLD for achieving the above-mentioned purpose may include: enabling a first AP associated with the AP MLD to send a first frame to a first station (STA) associated with the STA MLD on a first link; enabling a second AP associated with the AP MLD to send a second frame to a second STA associated with the STA MLD on a second link; in response to a transmission failure of the first frame, enabling the first AP to retransmit the first frame to the first STA on the first link; and receiving a first reception response frame of the first frame from the first STA on the first link, wherein the first reception response frame may include first reception status information of the first frame and second reception status information of the second frame.

[0017] The STA MLD may be a non-simultaneous transmission and reception (NSTR) STA MLD that does not support simultaneous transmission and reception (STR) operation, and when transmission of a second reception response frame of a second frame interferes with reception of a first frame, second reception status information may be included in the first reception response frame.

[0018] The first reception response frame may include a first medium access control (MAC) layer protocol data unit (MPDU) including first reception status information and a second MPDU including second reception status information.

[0019] The transmission of the first frame and the transmission of the second frame may be performed simultaneously, and the transmission end time of the first frame may be earlier than the transmission end time of the second frame.

[0020] Transmission of the first frame may be performed in a first transmission opportunity (TXOP) configured by the first STA, and transmission of the second frame may be performed in a second TXOP configured by the second STA.

[0021] The method may further include enabling the second AP to receive a second reception response frame of the second frame from the second STA on the second link after the retransmission operation of the first frame is completed on the first link.

[0022] Beneficial Effects

[0023] According to the present invention, in consideration of the multi-link operation of a non-simultaneous transmission and reception (NSTR) device, transmission that interferes with the reception operation of the NSTR device may not be performed. Through this operation, the reception operation of the NSTR device can be effectively performed. If an error occurs in the data, the NSTR device can quickly recover from the error in the data. Therefore, the reliability of data transmission can be improved, and transmission delay can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a block diagram showing a first exemplary embodiment of a communication node constituting a wireless LAN system.

[0025] Figure 2 is a conceptual diagram showing a first exemplary embodiment of multi-links configured between multi-link devices (MLDs).

[0026] Figure 3a is a timing diagram showing a first exemplary embodiment of an error recovery method in multi-link transmission for an NSTR device.

[0027] Figure 3b is a timing diagram showing a second exemplary embodiment of an error recovery method in multi-link transmission of an NSTR device.

[0028] Figure 4a is a timing diagram showing a third exemplary embodiment of an error recovery method in multi-link transmission of an NSTR device.

[0029] Figure 4b is a timing diagram showing a fourth exemplary embodiment of an error recovery method in multi-link transmission of an NSTR device.

[0030] Figure 5a is a timing diagram showing a fifth exemplary embodiment of an error recovery method in multi-link transmission of an NSTR device.

[0031] Figure 5b is a timing diagram showing a sixth exemplary embodiment of an error recovery method in multi-link transmission of an NSTR device. DETAILED DESCRIPTION

[0032] Since the present invention can be variously modified and has several forms, specific exemplary embodiments will be shown in the attached drawings and described in detail in the specific embodiments. However, it should be understood that this is not intended to limit the present invention to specific exemplary embodiments, on the contrary, the present invention is intended to cover all modifications and alternative forms falling within the spirit and scope of the present invention.

[0033] Relational terms such as first, second, etc. can be used to describe various elements, but these elements should not be limited by the terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the present invention, the first component can be named as the second component, and the second component can also be similarly named as the first component. The term "and / or" means any one or a combination of multiple related and described matters.

[0034] In an exemplary embodiment of the present invention, "at least one of A and B" may mean "at least one of A or B" or "at least one of a combination of one or more of A and B". In addition, "one or more of A and B" may mean "one or more of A or B" or "one or more of a combination of one or more of A and B".

[0035] When it is mentioned that a certain component is "coupled" or "connected" to another component, it should be understood that the certain component is directly "coupled" or "connected" to the other component, or other components may be arranged between them. On the contrary, when it is mentioned that a certain component is "directly coupled" or "directly connected" to another component, it should be understood that no other components are arranged between them.

[0036] The terms used in the present invention are only used to describe specific exemplary embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In the present invention, terms such as "including" or "having" are intended to indicate the presence of features, values, steps, operations, components, parts, or combinations thereof described in the specification, but it should be understood that these terms do not exclude the presence or addition of one or more features, values, steps, operations, components, parts, or combinations thereof.

[0037] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as those generally understood by ordinary technicians in the field to which the present invention belongs. Terms that are commonly used and have appeared in dictionaries should be interpreted as having meanings that match the contextual meanings in the field. In this specification, unless explicitly defined, terms are not necessarily interpreted as having formal meanings.

[0038] Hereinafter, the form of the present invention will be described in detail with reference to the attached drawings. In describing the present invention, in order to facilitate a comprehensive understanding of the present invention, the same reference numerals refer to the same elements throughout the description of the drawings, and their repeated description will be omitted.

[0039] Hereinafter, a wireless communication system according to an exemplary embodiment of the present invention will be described. The wireless communication system according to the exemplary embodiment of the present invention is not limited to the content described below, and can be applied to various wireless communication networks according to the exemplary embodiment of the present invention. The wireless communication system can be referred to as a "wireless communication network".

[0040] In an exemplary embodiment, "configuration of an operation (e.g., a transmission operation)" may mean signaling "configuration information (e.g., information element, parameter) of an operation" and / or "information indicating execution of an operation". "Configuration of an information element (e.g., parameter)" may mean signaling an information element. "Configuration of a resource (e.g., a resource region)" may mean signaling setting information of a resource.

[0041] Figure 1 is a block diagram showing a first exemplary embodiment of a communication node constituting a wireless LAN system.

[0042] like Figure 1 As shown, the communication node 100 may be an access point, a station, an access point (AP) multi-link device (MLD), or a non-AP MLD. An access point may be referred to as an "AP", and a station may be referred to as a "STA" or a "non-AP STA". The operating channel width supported by the AP may be 20 megahertz (MHz), 80 MHz, 160 MHz, etc. The operating channel width supported by the STA may be 20 MHz, 80 MHz, etc.

[0043] The communication node 100 may include at least one processor 110, a memory 120, and a transceiver 130 connected to a network to perform communication. The transceiver 130 may be referred to as a transceiver, a radio frequency (RF) unit, an RF module, etc. In addition, the communication node 100 may further include an input interface device 140, an output interface device 150, a storage device 160, etc. The various components included in the communication node 100 may be connected to communicate with each other through a bus 170.

[0044] However, the respective components included in the communication node 100 may be connected through a separate interface or a separate bus centered around the processor 110 instead of the common bus 170. For example, the processor 110 may be connected to at least one of the memory 120, the transceiver 130, the input interface device 140, the output interface device 150, and the storage device 160 through a dedicated interface.

[0045] The processor 110 may execute program instructions stored in at least one of the memory 120 and the storage device 160. The processor 110 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor that executes a method according to an exemplary embodiment of the present invention. Each of the memory 120 and the storage device 160 may be configured as at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 120 may be configured with at least one of a read-only memory (ROM) and a random access memory (RAM).

[0046] Figure 2 is a conceptual diagram showing a first exemplary embodiment of multi-links configured between multi-link devices (MLDs).

[0047] like Figure 2 As shown, the MLD may have a media access control (MAC) address. In an exemplary embodiment, the MLD may refer to an AP MLD and / or a non-AP MLD. The MAC address of the MLD may be used in a multi-link establishment process between a non-AP MLD and an AP MLD. The MAC address of the AP MLD may be different from the MAC address of the non-AP MLD. The AP associated with the AP MLD may have a different MAC address, and the station associated with the non-AP MLD may have a different MAC address. Each AP with a different MAC address within the AP MLD may be responsible for each link and may function as an independent AP.

[0048] Each STA with a different MAC address within a non-AP MLD may be responsible for each link and may function as an independent STA. A non-AP MLD may be referred to as a STA MLD. An MLD may support simultaneous transmit and receive (STR) operations. In this case, the MLD may perform a transmit operation in link 1 and may perform a receive operation in link 2. An MLD that supports STR operations may be referred to as an STR MLD (e.g., STR AP MLD, STR non-AP MLD). In an exemplary embodiment, a link may mean a channel or a frequency band. A device that does not support STR operations may be referred to as a non-STR (NSTR) AP MLD or an NSTR non-AP MLD (or NSTR STAMLD).

[0049] MLD can send and receive frames in multiple links by utilizing a non-contiguous bandwidth extension scheme (e.g., 80MHz+80MHz). Multi-link operation can include multi-band transmission. AP MLD can include multiple APs, and the multiple APs can operate in different links. Each of the multiple APs can perform the function of a lower MAC layer. Each of the multiple APs can be referred to as a "communication node" or a "lower entity". The communication node (i.e., AP) can be in the upper layer (or Figure 1 The non-AP MLD may include multiple STAs, and the multiple STAs may operate in different links. Each of the multiple STAs may be referred to as a "communication node" or a "lower entity". The communication node (i.e., STA) may be in an upper layer (or Figure 1 Operates under the control of the processor 110 shown.

[0050] MLD can perform communication in multiple frequency bands (i.e., multi-band). For example, MLD can perform communication using 40MHz bandwidth according to a channel extension scheme (e.g., bandwidth extension scheme) on the 2.4GHz band, and perform communication using 160MHz bandwidth according to a channel extension scheme on the 5GHz band. MLD can perform communication using 160MHz bandwidth in the 5GHz band, and can perform communication using 160MHz bandwidth in the 6GHz band. A frequency band (e.g., a channel) utilized by MLD can be defined as a link. Alternatively, multiple links can be configured in a frequency band utilized by MLD. For example, MLD can configure one link in the 2.4GHz band, and two links in the 6GHz band. Each link can be referred to as a first link, a second link, and a third link. Alternatively, each link can be referred to as link 1, link 2, link 3, etc. The link number can be set by the access point, and an identifier (ID) can be assigned to each link.

[0051] MLD (e.g., AP MLD and / or non-AP MLD) can configure multi-link by performing an access process and / or a negotiation process for multi-link operation. In this case, the number and / or links to be utilized in the multi-link can be configured. Non-AP MLD (e.g., STA) can identify information on a frequency band that can communicate with AP MLD. In the negotiation process of multi-link operation between non-AP MLD and APMLD, non-AP MLD can configure one or more links of the links supported by AP MLD for multi-link operation. A station that does not support multi-link operation (e.g., IEEE 802.11a / b / g / n / ac / ax STA) can be connected to one or more links of the multi-link supported by AP MLD.

[0052] When the frequency band spacing between multiple links (for example, the frequency band spacing between link 1 and link 2 in the frequency domain) is sufficient, the MLD may be able to perform the STR operation. For example, the MLD can use link 1 among the multiple links to send physical layer protocol data unit (PHY (physical) layer protocol data unit, PPDU) 1, and can use link 2 among the multiple links to receive PPDU2. On the other hand, if the MLD performs the STR operation when the frequency band spacing between the multiple links is insufficient, in-device coexistence (IDC) interference, which is interference between the multiple links, may occur. Accordingly, when the bandwidth spacing between the multiple links is insufficient, the MLD may not be able to perform the STR operation. The link pair having the above-mentioned interference relationship may be a link pair with non-simultaneous transmit and receive (NSTR) restrictions. Here, the MLD may be referred to as an "NSTR AP MLD" or an "NSTR non-AP MLD."

[0053] For example, a multilink including link 1, link 2, and link 3 may be configured between the AP MLD and the non-AP MLD 1. When the frequency band interval between link 1 and link 3 is sufficient, the AP MLD may perform the STR operation using link 1 and link 3. That is, the AP MLD may send a frame using link 1 and receive a frame using link 3. When the frequency band interval between link 1 and link 2 is insufficient, the AP MLD may not be able to perform the STR operation using link 1 and link 2. When the frequency band interval between link 2 and link 3 is insufficient, the AP MLD may not be able to perform the STR operation using link 2 and link 3.

[0054] On the other hand, in a wireless local area network system, a negotiation process for multi-link operation can be performed in an access process between a station and an access point. A device (e.g., access point, station) that supports multiple links can be referred to as a "multi-link device (MLD)". An access point that supports multiple links can be referred to as an "AP MLD", and a station that supports multiple links can be referred to as a "non-APMLD" or "STAMLD". AP MLD can have a physical address (e.g., MAC address) for each link. AP MLD can be implemented as if there is an AP responsible for each link alone. Multiple APs can be managed within one AP MLD. Therefore, coordination between multiple APs belonging to the same AP MLD is possible. STAMLD can have a physical address (e.g., MAC address) for each link. STA MLD can be implemented as if there is an STA responsible for each link alone. Multiple STAs can be managed within one STA MLD. Therefore, coordination between multiple STAs belonging to the same STAMLD is possible.

[0055] For example, AP 1 of AP MLD and STA 1 of STAMLD may each be responsible for the first link and perform communication using the first link. AP 2 of AP MLD and STA 2 of STAMLD may each be responsible for the second link and perform communication using the second link. STA 2 may receive state change information for the first link on the second link. In this case, STAMLD may collect information (e.g., state change information) received on each link and control the operation performed by STA 1 based on the collected information.

[0056] Hereinafter, a data transmission and reception method in a wireless local area network system will be described. Even when describing a method (e.g., transmission or reception of a signal) performed at a first communication node among communication nodes, the corresponding second communication node may also perform a method (e.g., reception or transmission of a signal) corresponding to the method performed at the first communication node. That is, when describing the operation of an STA, an AP corresponding thereto may perform an operation corresponding to the operation of the STA. Conversely, when describing the operation of an AP, an STA corresponding thereto may perform an operation corresponding to the operation of the AP.

[0057] In an exemplary embodiment, the operation of STA may be interpreted as the operation of STA MLD, the operation of STAMLD may be interpreted as the operation of STA, the operation of AP may be interpreted as the operation of AP MLD, and the operation of AP MLD may be interpreted as the operation of AP. The STA of STAMLD may refer to the STA associated with STAMLD, and the AP of AP MLD may refer to the AP associated with AP MLD. When STA MLD includes a first STA operating on a first link and a second STA operating on a second link, the operation of STA MLD on the first link may be interpreted as the operation of the first STA, and the operation of STAMLD on the second link may be interpreted as the operation of the second STA. When AP MLD includes a first AP operating on the first link and a second AP operating on the second link, the operation of AP MLD on the first link may be interpreted as the operation of the first AP, and the operation of AP MLD on the second link may be interpreted as the operation of the second AP. In an exemplary embodiment, the transmission time of a frame may refer to the transmission start time or the transmission end time, and the reception time of a frame may refer to the reception start time or the reception end time. The transmission time may be interpreted as corresponding to the reception time. The time point may be interpreted as time, and the time may be interpreted as the time point.

[0058] Figure 3a is a timing diagram showing a first exemplary embodiment of an error recovery method in multi-link transmission for an NSTR device.

[0059] like Figure 3a As shown, STAMLD 1 may be an NSTR STA MLD that does not support STR operation. The first link and the second link (on which STAMLD 1 operates) may be an NSTR link pair. In other words, STA1 and STA 2 may be STAs operating on an NSTR link pair. STA MLD 1 may perform synchronous transmissions on multiple links, and AP MLD 1 may perform synchronous transmissions on multiple links for STAMLD 1 (e.g., NSTR STA MLD). For example, STA 1 and STA 2 may transmit frames simultaneously.

[0060] STA1 can perform an initial transmission of a frame (e.g., a data frame, an uplink frame) on a first link, and can receive a response frame for the frame. Through the transmission operation of the frame, STA 1 can configure a transmission opportunity (transmit opportunity, TXOP) on the first link. In other words, STA1 can be granted a TXOP, and STA1 can be a TXOP holder. STA2 can perform an initial transmission of a frame (e.g., a data frame, an uplink frame) on a second link, and can receive a response frame for the frame. Through the transmission operation of the frame, STA2 can configure a TXOP on a second link. In other words, STA 2 can be granted a TXOP, and STA2 can be a TXOP holder. In the present invention, a frame may refer to a physical layer protocol data unit (PPDU), a MAC layer protocol data unit (MPDU), or an aggregate (A)-MPDU. The response frame may be an acknowledgment (ACK) frame or a block ACK (BA) frame.

[0061] Frame transmission can be performed multiple times within a TXOP. In other words, if the initial transmission of a frame is successful, STA1 and STA2 can perform multiple frame transmissions within a TXOP. The time difference between the end time of the first frame transmitted by STA 1 on the first link and the end time of the second frame transmitted by STA 2 on the second link can be up to 8 μs. The end time of the first frame transmitted by STA1 on the first link can be earlier than the end time of the second frame transmitted by STA 2 on the second link.

[0062] STA 1 may transmit a first frame on a first link, and may not receive a reception response frame (e.g., a BA frame) within a preset time (e.g., a priority interframe space (PIFS)) from the transmission time of the first frame. In other words, the transmission of the first frame may fail. Since STA 1 is a TXOP holder, STA 1 may perform a PIFS recovery operation and perform a retransmission operation of the first frame.

[0063] AP MLD 1 may recognize that the reception operation of the first frame on the first link is completed before the reception operation of the second frame on the second link. In this case, AP 2 may transmit a reception response frame of the second frame after a preset time (e.g., PIFS) from the reception end time of the second frame on the second link. When AP 2 waits for the preset time (e.g., PIFS) to transmit the reception response frame of the second frame, STA 1 may perform a retransmission operation of the first frame on the first link. AP1 may receive the first frame (e.g., the retransmitted frame) from STA 1. In this case, if AP 2 transmits the reception response frame on the second link, since STA MLD 1 operates on the NSTR link pair, STA 2 may not be able to receive the reception response frame of the second frame on the second link due to the retransmission of the first frame on the first link. In other words, the retransmission of the first frame on the first link may interfere with the reception of the reception response frame of the second frame on the second link.

[0064] Therefore, when performing a retransmission operation (e.g., a retransmission operation of the first frame) of STA 1 on the first link, AP 2 may not transmit a reception response frame of the second frame on the second link. If AP 2 does not transmit a reception response frame on the second link, AP MLD 1 may notify the reception status of the second frame based on one or more of the following methods.

[0065] (Method 1)

[0066] AP MLD 1 may notify the reception status of the second frame using a reception response frame for the first frame retransmitted by STA 1. For example, AP MLD 1 (e.g., AP 1) may generate a reception response frame including reception status information of the first frame retransmitted on the first link and reception status information of the second frame on the second link, and transmit the reception response frame on the first link in response to the retransmitted first frame. The reception status of the first frame and the reception status of the second frame may be indicated by a single reception response frame. Alternatively, a first reception response frame indicating the reception status of the first frame and a second reception response frame indicating the reception status of the second frame may be generated, and a single reception response frame including both the first reception response frame and the second reception response frame may be generated. The single reception response frame may have the form of an A-MPDU. In other words, the reception response frame may include a first MPDU containing the reception status information of the first frame and a second MPDU containing the reception status information of the second frame.

[0067] (Method 2)

[0068] AP 2 of AP MLD 1 may suspend transmission of a reception response frame of a second frame until a retransmission operation of a first frame of STA 1 is completed. After the retransmission operation of the first frame of STA 1 is completed, AP 2 may perform a channel access operation (e.g., a backoff operation) on the second link before transmitting the reception response frame of the second frame. Alternatively, after the retransmission operation of the first frame by STA 1 is completed, AP 2 may transmit the reception response frame of the second frame on the second link without performing a channel access operation. Alternatively, AP 2 may transmit the reception response frame of the second frame after a preset time (e.g., short interframe space (SIFS), PIFS, extended interframe space (EIFS), distributed coordination function interframe space (DCF (distributed coordination function) interframe space, DIFS), or arbitrary interframe space (AIFS)) from the completion time of the retransmission operation of the first frame of STA 1.

[0069] One of (method 1) or (method 2) may be used. Alternatively, (method 1) and (method 2) may be performed together. For example, based on (method 1), a reception response frame including reception status information of the first retransmission frame and reception status information of the second frame may be sent and received on the first link. In addition, based on (method 2), after the retransmission operation of the first frame is completed, a reception response frame of the second frame may be sent and received on the first link.

[0070] On the first link, STA 1 may not perform a retransmission operation of the first frame based on the PIFS recovery operation. If a retransmission operation of the first frame is not performed on the first link, AP 2 may transmit a reception response frame of the second frame on the second link after a preset time (e.g., PIFS or SIFS) from the reception time of the second frame.

[0071] Figure 3b is a timing diagram showing a second exemplary embodiment of an error recovery method in multi-link transmission of an NSTR device.

[0072] like Figure 3bAs shown, STAMLD 1 may be an NSTR STA MLD that does not support STR operation. The first link and the second link (on which STA MLD 1 operates) may be an NSTR link pair. In other words, STA 1 and STA 2 may be STAs operating on an NSTR link pair. STA MLD 1 may perform synchronous transmissions on multiple links, and AP MLD 1 may perform synchronous transmissions on multiple links for STAMLD 1 (e.g., NSTR STA MLD). For example, STA 1 and STA 2 may transmit frames simultaneously.

[0073] AP 1 may perform an initial transmission of a frame (e.g., a data frame, a downlink frame) on a first link, and may receive a reception response frame for the frame. Through the transmission operation of the frame, AP 1 may configure a TXOP on the first link. In other words, a TXOP may be granted to AP 1, and AP 1 may be a TXOP holder. AP 2 may perform an initial transmission of a frame (e.g., a data frame, a downlink frame) on a second link, and may receive a reception response frame for the frame. In other words, a TXOP may be granted to AP 2. Through the transmission operation of the frame, AP 2 may configure a TXOP on the second link, and AP 2 may be a TXOP holder.

[0074] Frame transmission can be performed multiple times within a TXOP. In other words, if the initial transmission of the frame is successful, AP 1 and AP 2 can perform multiple frame transmissions within the TXOP. The time difference between the end time of the first frame transmitted by AP 1 on the first link and the end time of the second frame transmitted by AP 2 on the second link can be up to 8 μs. The end time of the first frame transmitted by AP 1 on the first link can be earlier than the end time of the second frame transmitted by AP 2 on the second link.

[0075] AP 1 may transmit the first frame on the first link, and may not receive a reception response frame (e.g., a BA frame) within a preset time (e.g., PIFS) from the transmission time of the first frame. In other words, the transmission of the first frame may fail. Since AP 1 is the TXOP holder, AP 1 may perform a PIFS recovery operation and perform a retransmission operation of the first frame.

[0076] STA MLD 1 may recognize that the reception operation of the first frame on the first link is completed before the reception operation of the second frame on the second link. In this case, STA 2 may transmit a reception response frame of the second frame after a preset time (e.g., PIFS) from the reception end time of the second frame on the second link. While STA2 waits for the preset time (e.g., PIFS) to transmit the reception response frame of the second frame, AP 1 may perform a retransmission operation of the first frame on the first link. STA 1 may receive the first frame (e.g., the retransmitted frame) from AP 1. In this case, if STA 2 transmits the reception response frame on the second link, since STA MLD 1 operates on the NSTR link pair, the transmission of the reception response frame of STA 2 may interfere with the reception of the first frame retransmitted by AP 1. A reception error of the retransmitted first frame may occur.

[0077] Therefore, when performing a retransmission operation (e.g., a retransmission operation of the first frame) of AP 1 on the first link, STA2 may not transmit a reception response frame of the second frame on the second link. If STA2 does not transmit a reception response frame on the second link, STAMLD 1 may notify the reception status of the second frame based on one or more of the following methods.

[0078] (Method 1)

[0079] STA MLD 1 may notify the reception status of the second frame using a reception response frame for the first frame retransmitted by AP 1. For example, STA MLD 1 (e.g., STA 1) may generate a reception response frame including reception status information of the first frame retransmitted on the first link and reception status information of the second frame on the second link, and transmit the reception response frame on the first link in response to the retransmitted first frame. The reception status of the first frame and the reception status of the second frame may be indicated by a single reception response frame. Alternatively, a first reception response frame indicating the reception status of the first frame and a second reception response frame indicating the reception status of the second frame may be generated, and a single reception response frame including both the first reception response frame and the second reception response frame may be generated. The single reception response frame may have the form of an A-MPDU. In other words, the reception response frame may include a first MPDU containing the reception status information of the first frame and a second MPDU containing the reception status information of the second frame.

[0080] (Method 2)

[0081] STA 2 of STAMLD 1 may suspend transmission of a reception response frame of the second frame until the retransmission operation of the first frame of AP 1 is completed. After the retransmission operation of the first frame of AP 1 is completed, STA 2 may perform a channel access operation (e.g., a backoff operation) on the second link before transmitting the reception response frame of the second frame. Alternatively, after the retransmission operation of the first frame is completed by AP 1, STA 2 may transmit the reception response frame of the second frame on the second link without performing a channel access operation. Alternatively, STA 2 may transmit the reception response frame of the second frame after a preset time (e.g., SIFS, PIFS, EIFS, DIFS, or AIFS) from the completion time of the retransmission operation of the first frame of AP 1.

[0082] One of (method 1) or (method 2) may be used. Alternatively, (method 1) and (method 2) may be performed together. For example, based on (method 1), a reception response frame including reception status information of the first retransmission frame and reception status information of the second frame may be sent and received on the first link. In addition, based on (method 2), after the retransmission operation of the first frame is completed, a reception response frame of the second frame may be sent and received on the first link.

[0083] On the first link, AP 1 may not perform a retransmission operation of the first frame based on a PIFS recovery operation. If a retransmission operation of the first frame is not performed on the first link, STA 2 may transmit a reception response frame of the second frame on the second link after a preset time (e.g., PIFS or SIFS) from the reception time of the second frame.

[0084] Figure 4a is a timing diagram showing a third exemplary embodiment of an error recovery method in multi-link transmission of an NSTR device.

[0085] like Figure 4a As shown, STA MLD 1 may be an NSTR STA MLD that does not support STR operation. The first link and the second link (on which STA MLD 1 operates) may be an NSTR link pair. In other words, STA1 and STA2 may be STAs operating on an NSTR link pair. STA MLD 1 may perform synchronous transmissions on multiple links, and AP MLD 1 may perform synchronous transmissions on multiple links for STA MLD 1 (e.g., NSTR STA MLD). For example, STA 1 and STA 2 may transmit frames simultaneously.

[0086] STA 1 can perform an initial transmission of a frame (e.g., a data frame, an uplink frame) on the first link, and can receive a reception response frame for the frame. Through the transmission operation of the frame, STA 1 can configure a TXOP on the first link. In other words, a TXOP can be granted to STA 1. STA 1 can be a TXOP holder. STA 2 can perform an initial transmission of a frame (e.g., a data frame, an uplink frame) on the second link, and can receive a reception response frame for the frame. Through the transmission operation of the frame, STA 2 can configure a TXOP on the second link. In other words, a TXOP can be granted to STA 2, and STA 2 can be a TXOP holder.

[0087] Frame transmission can be performed multiple times within a TXOP. In other words, if the initial transmission of the frame is successful, STA1 and STA2 can perform multiple frame transmissions within the TXOP. The transmission start time of STA 1's frame on the first link can be synchronized with the transmission start time of STA 2's frame on the second link. The transmission end time of STA 1's frame on the first link can be synchronized with the transmission end time of AP2's frame on the second link.

[0088] On the first link, STA1 may send a first frame to AP 1 and receive a reception response frame for the first frame from AP 1. On the second link, STA 2 may send a second frame to AP 2, but may not receive a reception response frame for the second frame within AckTimeout (e.g., aSIFSTime+aSlotTime+aRxPHYStartDelay) from the transmission time of the second frame. In this case (e.g., if the preamble detection fails), STA 2 may transmit a dummy frame. The dummy frame transmitted by STA2 may be a CTS frame including a receiver address (RA) set to STA2. In other words, the dummy frame may be a reflexive CTS (CTS (clear to send)-to-Self) frame. Alternatively, the dummy frame may be a CTS frame sent to AP 2. The dummy frame may also be a frame other than a CTS frame (e.g., a QoS data frame or a QoS empty frame).

[0089] The dummy frame of STA 2 may be transmitted until the end time (e.g., the predicted end time) of the reception response frame of the second frame. In other words, the end time of the dummy frame may be synchronized with the end time of the reception response frame of the second frame. Alternatively, the dummy frame of STA 2 may be transmitted until the end time (e.g., the predicted end time) of the reception response frame for the first frame on the first link. In other words, the end time of the dummy frame may be synchronized with the end time of the reception response frame for the first frame.

[0090] To avoid causing interference to STA1 (eg, NSTR STA MLD) associated with STA MLD 1, STA2 may transmit a dummy frame at low power. The dummy frame may be generated based on a low modulation and coding scheme (MCS). The dummy frame with low power may be decoded based on a low MCS.

[0091] The end time (e.g., predicted end time) of the reception response frame of the second frame on the second link and / or the end time (e.g., predicted end time) of the reception response frame of the first frame on the first link may be configured between AP MLD 1 and STA MLD 1 through single response scheduling (SRS). Alternatively, SRS may not be used. In this case, STA MLD 1 may predict the end time of the reception response frame based on a traffic identifier (TID) and / or a negotiated BA bitmap size.

[0092] If the preamble detection of the reception response frame on the second link fails, and the channel is determined to be in an idle state through energy detection and / or clear channel assessment (CCA), STA 2 may transmit a dummy frame. Alternatively, if the preamble detection of the reception response frame on the second link fails, and the channel is determined to be in a busy state through energy detection and / or CCA, STA 2 may transmit a dummy frame. Alternatively, if the preamble detection of the reception response frame on the second link fails, STA 2 may transmit a dummy frame without considering energy detection and / or CCA.

[0093] Figure 4b is a timing diagram showing a fourth exemplary embodiment of an error recovery method in multi-link transmission of an NSTR device.

[0094] like Figure 4b As shown, STAMLD 1 may be an NSTR STA MLD that does not support STR operation. The first link and the second link (on which STA MLD 1 operates) may be an NSTR link pair. In other words, STA 1 and STA 2 may be STAs operating on an NSTR link pair. STA MLD 1 may perform synchronous transmissions on multiple links, and AP MLD 1 may perform synchronous transmissions on multiple links for STAMLD 1 (e.g., NSTR STA MLD). For example, STA 1 and STA 2 may transmit frames simultaneously.

[0095] AP 1 may perform an initial transmission of a frame (e.g., a data frame, a downlink frame) on a first link, and may receive a reception response frame for the frame. Through the transmission operation of the frame, AP 1 may configure a TXOP on the first link. In other words, a TXOP may be granted to AP 1. AP 1 may be a TXOP holder. AP 2 may perform an initial transmission of a frame (e.g., a data frame, a downlink frame) on a second link, and may receive a reception response frame for the frame. Through the transmission operation of the frame, AP 2 may configure a TXOP on the second link. In other words, a TXOP may be granted to AP 2. AP 2 may be a TXOP holder.

[0096] Frame transmission can be performed multiple times within a TXOP. In other words, if the initial transmission of the frame is successful, AP 1 and AP 2 can perform multiple frame transmissions within the TXOP. The transmission start time of STA 1's frame on the first link can be synchronized with the transmission start time of STA 2's frame on the second link. The transmission end time of STA 1's frame on the first link can be synchronized with the transmission end time of AP 2's frame on the second link.

[0097] On the first link, AP 1 may send a first frame to STA 1 and receive a reception response frame for the first frame from STA 1. On the second link, AP 2 may send a second frame to STA 2, but may not receive a reception response frame for the second frame within the AckTimeout time (e.g., aSIFSTime+aSlotTime+aRxPHYStartDelay) from the transmission time of the second frame. In this case (e.g., if the preamble detection fails), AP 2 may transmit a dummy frame. The dummy frame transmitted by AP 2 may be a CTS frame including a receiver address (RA) set to AP 2. In other words, the dummy frame may be a reflexive CTS frame. Alternatively, the dummy frame may be a CTS frame sent to STA 2. The dummy frame may also be a frame other than a CTS frame (e.g., a QoS data frame or a QoS empty frame).

[0098] The dummy frame of AP 2 may be transmitted until the end time (e.g., the predicted end time) of the reception response frame of the second frame. In other words, the end time of the dummy frame may be synchronized with the end time of the reception response frame of the second frame. Alternatively, the dummy frame of AP 2 may be transmitted until the end time (e.g., the predicted end time) of the reception response frame for the first frame on the first link. In other words, the end time of the dummy frame may be synchronized with the end time of the reception response frame for the first frame.

[0099] The end time (e.g., predicted end time) of the reception response frame of the second frame on the second link and / or the end time (e.g., predicted end time) of the reception response frame for the first frame on the first link may be configured between AP MLD 1 and STAMLD 1 through SRS. Alternatively, SRS may not be used. In this case, AP MLD 1 may predict the end time of the reception response frame based on TID and / or the negotiated BA bitmap size.

[0100] If the preamble detection of the received response frame on the second link fails, and the channel is determined to be in an idle state through energy detection and / or clear channel assessment (CCA), AP 2 may transmit a dummy frame. Alternatively, if the preamble detection of the received response frame on the second link fails, and the channel is determined to be in a busy state through energy detection and / or CCA, AP 2 may transmit a dummy frame. Alternatively, if the preamble detection of the received response frame on the second link fails, AP 2 may transmit a dummy frame without considering energy detection and / or CCA.

[0101] Figure 5a is a timing diagram showing a fifth exemplary embodiment of an error recovery method in multi-link transmission of an NSTR device.

[0102] like Figure 5a As shown, STAMLD 1 may be an NSTR STA MLD that does not support STR operation. The first link and the second link (on which STAMLD 1 operates) may be an NSTR link pair. In other words, STA1 and STA2 may be STAs operating on an NSTR link pair. STAMLD 1 may perform synchronous transmissions on multiple links, and AP MLD 1 may perform synchronous transmissions on multiple links for STAMLD 1 (e.g., NSTR STA MLD). For example, STA 1 and STA 2 may transmit frames simultaneously.

[0103] STA 1 may perform an initial transmission of a frame (e.g., a data frame, an uplink frame) on the first link, and may receive a reception response frame for the frame. Through the frame transmission operation, STA 1 may configure a TXOP on the first link. In other words, a TXOP may be granted to STA 1. STA 1 may be a TXOP holder. STA 2 may perform an initial transmission of a frame (e.g., a data frame, an uplink frame) on the second link, and may receive a reception response frame for the frame. Through the frame transmission operation, STA 2 may configure a TXOP on the second link. In other words, a TXOP may be granted to STA 2. STA 2 may be a TXOP holder.

[0104] Frame transmission can be performed multiple times within a TXOP. In other words, if the initial transmission of a frame is successful, STA1 and STA2 can perform multiple frame transmissions within a TXOP. The time difference between the end time of the first frame transmitted by STA1 on the first link and the end time of the second frame transmitted by STA 2 on the second link can be up to 8 μs. The end time of the first frame transmitted by STA1 on the first link can be earlier than the end time of the second frame transmitted by STA 2 on the second link.

[0105] STA1 may not receive a reception response frame for the first frame within a preset time (e.g., SIFS) from the end time of the transmission of the first frame. For example, STA 1 may not detect the preamble of the reception response frame for the first frame, and may determine that the channel is in a busy state through energy detection and / or CCA. In the retransmission process for the first frame on the first link, a synchronous channel access operation between the first link and the second link may be impossible. Therefore, on the first link, STA1 may retransmit the first frame after a preset time (e.g., SIFS) from the end time of the busy state of the channel. Alternatively, after the end time of the busy state of the channel, the retransmission operation of the first frame of STA1 and the transmission operation of the third frame of STA 2 may be synchronized. In other words, the start time of the retransmission of the first frame of STA 1 may be synchronized with the start time of the transmission of the third frame of STA 2.

[0106] Figure 5b is a timing diagram showing a sixth exemplary embodiment of an error recovery method in multi-link transmission of an NSTR device.

[0107] like Figure 5b As shown, STAMLD 1 may be an NSTR STA MLD that does not support STR operation. The first link and the second link (on which STAMLD 1 operates) may be an NSTR link pair. In other words, STA1 and STA2 may be STAs operating on an NSTR link pair. STAMLD 1 may perform synchronous transmissions on multiple links, and AP MLD 1 may perform synchronous transmissions on multiple links for STAMLD 1 (e.g., NSTR STA MLD). For example, STA 1 and STA 2 may transmit frames simultaneously.

[0108] AP 1 may perform an initial transmission of a frame (e.g., a data frame, a downlink frame) on a first link, and may receive a reception response frame for the frame. Through the transmission operation of the frame, AP 1 may configure a TXOP on the first link. In other words, a TXOP may be granted to AP 1. AP 1 may be a TXOP holder. AP 2 may perform an initial transmission of a frame (e.g., a data frame, a downlink frame) on a second link, and may receive a reception response frame for the frame. Through the transmission operation of the frame, AP 2 may configure a TXOP on the second link. In other words, a TXOP may be granted to AP 2. AP 2 may be a TXOP holder.

[0109] Frame transmission can be performed multiple times within a TXOP. In other words, if the initial transmission of the frame is successful, AP 1 and AP 2 can perform multiple frame transmissions within the TXOP. The time difference between the end time of the first frame transmitted by AP 1 on the first link and the end time of the second frame transmitted by AP 2 on the second link can be up to 8 μs. The end time of the first frame transmitted by AP 1 on the first link can be earlier than the end time of the second frame transmitted by AP 2 on the second link.

[0110] AP 1 may not receive a reception response frame for the first frame within a preset time (e.g., SIFS) from the end time of transmission of the first frame. For example, AP 1 may not detect the preamble of the reception response frame for the first frame, and may determine that the channel is in a busy state through energy detection and / or CCA. In the retransmission process for the first frame on the first link, a synchronous channel access operation between the first link and the second link may be impossible. Therefore, on the first link, AP 1 may retransmit the first frame after a preset time (e.g., SIFS) from the end time of the busy state of the channel. The start time of retransmission of the first frame of AP 1 may be synchronized with the start time of transmission of the third frame of AP 2. Alternatively, the start time of retransmission of the first frame of AP 1 may be different from the start time of transmission of the third frame of AP 2. In this case, the difference between the retransmission start time of the first frame and the transmission start time of the third frame may be within a specific time (e.g., 8 μs). The end time of retransmission of the first frame of AP 1 may be the same as the end time of transmission of the third frame of AP 2. Alternatively, the end time of retransmission of the first frame of AP 1 may be different from the end time of transmission of the third frame of AP 2. In this case, the difference between the retransmission end time of the first frame and the transmission end time of the third frame may be within a specific time (eg, 8 μs).

[0111] The operation of the method according to the exemplary embodiment of the present invention can be implemented as a computer-readable program or code in a computer-readable recording medium. The computer-readable recording medium may include a recording device of all types having data that can be read by a computer system. In addition, the computer-readable recording medium can store and execute programs or codes, which can be distributed in a computer system connected via a network and read by a computer in a distributed manner.

[0112] Computer readable recording media may include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM or flash memory. Program instructions may include not only machine language codes created by a compiler, but also high-level language codes that can be executed by a computer using an interpreter.

[0113] Although some aspects of the present invention have been described in the context of a device, these aspects may indicate the corresponding description according to the method, and a block or device may correspond to the step of the method or the feature of the step. Similarly, the aspects described in the context of the method may be represented as the feature of a corresponding block or project or a corresponding device. Some or all steps of the method may be performed by (or using) a hardware device such as a microprocessor, a programmable computer or an electronic circuit. In some embodiments, one or more of the most important steps of the method may be performed by such a device.

[0114] In some exemplary embodiments, a programmable logic device such as a field programmable gate array can be used to perform some or all of the functions of the methods described herein. In some exemplary embodiments, the field programmable gate array can be operated with a microprocessor to perform one of the methods described herein. Typically, the method is preferably performed by a specific hardware device.

[0115] The description of the present invention is merely exemplary in nature, and therefore variant forms that do not deviate from the essence of the present invention are intended to be within the scope of the present invention. Such variant forms should not be considered as departing from the spirit and scope of the present invention. Therefore, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope defined by the appended claims.

Claims

1. A method of a station (STA) multi-link device (MLD), comprising: enabling a first STA associated with the STA MLD to send a first frame to a first access point (AP) associated with the AP MLD on a first link; enabling a second STA associated with the STA MLD to send a second frame to a second AP associated with the AP MLD on a second link; In response to a transmission failure of the first frame, enabling the first STA to retransmit the first frame to the first AP on the first link; as well as receiving a first reception response frame of the first frame from the first AP on the first link, The first reception response frame includes first reception status information of the first frame and second reception status information of the second frame.

2. The method according to claim 1, wherein: The STA MLD is a non-simultaneous transmission and reception (NSTR) STA MLD that does not support a simultaneous transmission and reception (STR) operation, and when retransmission of the first frame interferes with reception of a second reception response frame of the second frame, the second reception status information is included in the first reception response frame.

3. The method according to claim 1, wherein: The first reception response frame includes a first medium access control (MAC) layer protocol data unit (MPDU) including first reception status information and a second MPDU including second reception status information.

4. The method according to claim 1, wherein: The transmission of the first frame and the transmission of the second frame are performed simultaneously, and the transmission end time of the first frame is earlier than the transmission end time of the second frame.

5. The method according to claim 1, wherein: Transmission of a first frame is performed in a first transmission opportunity (TXOP) configured by a first STA, and transmission of a second frame is performed in a second TXOP configured by a second STA.

6. The method according to claim 1, further comprising: After the retransmission operation of the first frame on the first link is completed, the second STA is enabled to receive a second reception response frame of the second frame from the second AP on the second link.

7. A method of access point (AP) multi-link device (MLD), comprising: enabling a first AP associated with the AP MLD to send a first frame to a first station (STA) associated with the STA MLD on a first link; enabling a second AP associated with the AP MLD to send a second frame to a second STA associated with the STA MLD on a second link; In response to a transmission failure of the first frame, enabling the first AP to retransmit the first frame to the first STA over the first link; as well as receiving a first reception response frame of the first frame from the first STA on the first link, The first reception response frame includes first reception status information of the first frame and second reception status information of the second frame.

8. The method according to claim 7, wherein: The STA MLD is a non-simultaneous transmission and reception (NSTR) STA MLD that does not support a simultaneous transmission and reception (STR) operation, and when transmission of a second reception response frame of a second frame interferes with reception of a first frame, the second reception status information is included in the first reception response frame.

9. The method according to claim 7, wherein: The first reception response frame includes a first medium access control (MAC) layer protocol data unit (MPDU) including first reception status information and a second MPDU including second reception status information.

10. The method according to claim 7, wherein: The transmission of the first frame and the transmission of the second frame are performed simultaneously, and the transmission end time of the first frame is earlier than the transmission end time of the second frame.

11. The method according to claim 7, wherein: Transmission of a first frame is performed in a first transmission opportunity (TXOP) configured by a first STA, and transmission of a second frame is performed in a second TXOP configured by a second STA.

12. The method according to claim 7, further comprising: After the retransmission operation of the first frame is completed on the first link, the second AP is enabled to receive a second reception response frame of the second frame from the second STA on the second link.

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