Method and apparatus for updating parameter in multi-link supporting communication system

Abstract

The present invention relates to a method and an apparatus for updating parameters in a communication system supporting multiple links. A method and an apparatus for updating parameters in a communication system supporting multiple links are disclosed. An operation method for a first device comprises the steps of: transmitting a first frame to a second device through a first link of a plurality of links, the first frame including an updated parameter for a communication operation in the first link; transmitting a second frame to a second device over a second link of the plurality of links, the second frame including information indicating the presence of the updated parameter; and transmitting a third frame to the second device over one of the plurality of links, the third frame including the updated parameter.

Description

[0001] This application is a divisional application of Chinese PCT patent application No. 202180026680.2, entitled "Method and apparatus for updating parameters in a communication system supporting multiple links", filed on March 25, 2021. Technical Field

[0002] This invention relates to a wireless local area network (WLAN) communication technology, and more specifically to a technique for updating parameters in a multi-link wireless local area network. Background Technology

[0003] Recently, with the increasing distribution of mobile devices, wireless local area network (WLAN) technology, which provides fast wireless communication services for mobile devices, has attracted attention. WLAN technology is a technology that uses wireless communication to enable mobile devices such as smartphones, tablets, laptops, portable multimedia players, and embedded devices to wirelessly access the internet.

[0004] The standard for wireless LAN technology is primarily standardized within the Institute of Electrical and Electronics Engineers (IEEE) as the IEEE 802.11 standard. Initial versions of the IEEE 802.11 standard supported communication speeds of 1 to 2 megabits per second (Mbps). Later versions of the IEEE 802.11 standard have been standardized in the direction of increasing communication speeds.

[0005] The revised version of the IEEE 802.11a standard can support communication speeds of up to 54 Mbps in the 5 GHz band using Orthogonal Frequency Division Multiplexing (OFDM). The IEEE 802.11b standard, in its initial version operating in the 2.4 GHz band, uses Direct Sequence Spread Spectrum (DSSS) to support communication speeds of up to 11 Mbps.

[0006] Due to the demand for higher speeds, the IEEE 802.11n standard, supporting high-throughput (HT) wireless LAN technology, has been developed. The IEEE 802.11n standard supports OFDM schemes. By supporting channel bandwidth extension technology and multiple-input multiple-output (MIMO) technology in the IEEE 802.11n standard, the maximum communication speed in the 2.4 GHz and 5 GHz frequency bands can be improved. For example, the IEEE 802.11n standard can support communication speeds up to 600 Mbps by utilizing four spatial streams and a 40 MHz bandwidth.

[0007] With the development and widespread adoption of the aforementioned wireless LAN technologies, their applications have diversified, and a demand has emerged for wireless LAN technologies supporting higher throughput. Therefore, the frequency bandwidth utilized in the IEEE 802.11ac standard (e.g., "maximum 160 MHz bandwidth" or "80+80 MHz bandwidth") has been expanded, and the number of supported spatial streams has also increased. The IEEE 802.11ac standard can be a Very High Throughput (VHT) wireless LAN technology, supporting throughput of 1 gigabit per second (Gbps) or higher. The IEEE 802.11ac standard can support downlink transmission for multiple stations by utilizing MIMO technology.

[0008] With the increasing demand for wireless LAN technology, the IEEE 802.11ax standard has been developed to improve frequency efficiency in dense environments. The IEEE 802.11ax standard utilizes Multi-User (MU) Orthogonal Frequency Division Multiple Access (OFDMA) technology to perform communication. Uplink communication can be performed using MU MIMO and / or OFDMA technologies.

[0009] With the emergence of applications requiring higher throughput and real-time transmission, the IEEE 802.11be standard, an Extreme High Throughput (EHT) wireless LAN technology, is under development. The goal of the IEEE 802.11be standard is to support high throughput of 30 Gbps. The IEEE 802.11be standard can support technologies to reduce transmission latency. Furthermore, the IEEE 802.11be standard can support extended frequency bandwidth (e.g., 320 MHz bandwidth), multi-link transmission, and aggregation operations including multi-band operation, multiple access point (AP) transmission operation, and / or efficient retransmission operations (e.g., Hybrid Automatic Repeat Request (HARQ) operation).

[0010] However, since multilink operation is not defined in existing wireless LAN standards, detailed operation may need to be defined based on the environment in which it is performed. Specifically, when two or more frequency bands performing multilink operation are close to each other, simultaneous transmission and reception via multiple links may not be possible within a single device due to signal interference between adjacent links. In particular, when the signal interference level between adjacent links is equal to or greater than a certain level, backoff operations for transmission on another link may be impossible due to interference when performing transmission operations on one link. Therefore, in the above situations, a method for updating parameters for multilink operation is needed.

[0011] On the other hand, the techniques described in the background section are intended to enhance the understanding of the background of the present invention, and these techniques may include content that is not yet known to those skilled in the art to which the present invention pertains. Summary of the Invention

[0012] Technical issues The present invention aims to provide a method and apparatus for updating parameters in a wireless local area network system that supports multiple links.

[0013] Technical solution An operation method of the first device according to a first embodiment of the present invention for achieving the above-mentioned objective may include: sending a first frame to a second device via a first link in a multi-link network, the first frame including updated parameters for communication operations in the first link; sending a second frame to the second device via a second link in the multi-link network, the second frame including information indicating the existence of the updated parameters; and sending a third frame to the second device via one of the links in the multi-link network, the third frame including the updated parameters.

[0014] The first and second frames can be beacon frames, and the third frame can be a beacon frame or a probe response frame.

[0015] Beacon frames and probe response frames can be sent to multiple devices, including a second device, based on a broadcast scheme.

[0016] When the second device does not support simultaneous transmit and receive (STR) operation in multiple links and transmits data frames in the second link during the reception period of the first frame in the first link, the first frame may not be received by the second device.

[0017] The first and second frames can be sent periodically, and the third frame can be sent periodically or at the request of the second device or another device.

[0018] To ensure that the third frame is received in the second device, a transmission prohibition period can be configured on a link other than the one that transmits the third frame to prohibit transmission during the time when the third frame is transmitted.

[0019] The transmission prohibition period can be configured via instructions from the first device. The transmission prohibition period can be configured together with the link or channel to which transmission is prohibited.

[0020] The operation method of the second device according to a second embodiment of the present invention for achieving the above-mentioned objective may include: sending a data frame to a first device via a second link in a multi-link system; receiving a response frame from the first device via the second link in response to the data frame, the response frame including a response to the receipt of the data frame and a key update flag indicating that the parameters have been updated; and receiving a management frame including the updated parameters from the first device.

[0021] The response frame can be an acknowledgment (ACK) frame or a block ACK (BA) frame for a data frame.

[0022] Management frames can be received in the first link and a network allocation vector (NAV) for the second link can be set in the second device to ensure the reception of management frames.

[0023] Management frames can be beacon frames or probe response frames.

[0024] Beneficial effects According to the present invention, multiple links can be used to perform communication between the STA and the AP. When some of the multiple links (e.g., some channels) are adjacent, making simultaneous transmission / reception operations difficult, parameter update information may not be received on the first link if transmission operations are being performed on links other than the first link. To solve this problem, information indicating that the parameters used for the first link have changed can be transmitted on the second link. The transmission resources (e.g., time and / or frequency resources) used to indicate that the parameters have changed can be distinguished from the transmission resources used for other frames. Therefore, parameters can be updated quickly, and transmission efficiency can be improved. Attached Figure Description

[0025] Figure 1 This is a block diagram illustrating a first embodiment of a communication node constituting a wireless local area network system.

[0026] Figure 2 This is a conceptual diagram illustrating a first embodiment of multiple links configured between multi-link devices (MLDs).

[0027] Figure 3 This is a sequence diagram illustrating a first implementation of the negotiation process for multi-link operation in a wireless local area network system.

[0028] Figure 4a This is a timing diagram illustrating a first embodiment of a channel access method in a wireless local area network system that supports multiple links.

[0029] Figure 4b This is a timing diagram illustrating a second embodiment of a channel access method in a wireless local area network system that supports multiple links.

[0030] Figure 5 This is a timing diagram illustrating a first embodiment of a method for updating parameters in a wireless local area network system that supports multiple links.

[0031] Figure 6 This is a block diagram illustrating a first embodiment of a BA frame, which includes information indicating whether parameters have changed.

[0032] Figure 7 This is a block diagram illustrating a first embodiment of an ACK frame, which includes information indicating whether parameters have changed.

[0033] Figure 8 This is a timing diagram illustrating a second embodiment of a method for updating parameters in a multi-link wireless local area network system.

[0034] Figure 9This is a timing diagram illustrating a first embodiment of a method for setting up a Virtual Network Assignment Vector (NAV) for non-simultaneous transmission and reception (non-STR) in a wireless LAN system that supports multiple links.

[0035] Figure 10 This is a timing diagram illustrating a third embodiment of a method for updating parameters in a multi-link wireless local area network system.

[0036] Figure 11 This is a timing diagram illustrating a fourth embodiment of a method for updating parameters in a multi-link wireless local area network system.

[0037] Figure 12 This is a timing diagram illustrating a fifth embodiment of a method for updating parameters in a multi-link wireless local area network system. Detailed Implementation

[0038] Since various modifications and multiple forms can be made to some embodiments of the present invention, specific embodiments will be shown in the accompanying drawings and described in detail. However, it should be understood that the invention is not intended to be limited to the specific embodiments. Rather, the invention is intended to cover all modifications and alternatives falling within the spirit and scope of the invention.

[0039] 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. For example, without departing from the scope of the invention, a first component may be named a second component, and a second component may similarly be named a first component. The term "and / or" refers to any one or a combination of a plurality of related and described items.

[0040] When it is said that a component is "connected" or "connected" to another component, it should be understood that the component is directly "connected" or "connected" to the other component, or that another component may be provided between them. Conversely, when it is said that a component is "directly connected" or "directly linked" to another component, it should be understood that no other component is provided between them.

[0041] The terminology used in this invention is for describing particular embodiments only and is not intended to limit the invention. Singular expressions include plural expressions unless the context clearly specifies otherwise. In this invention, terms such as “comprising” or “having” are intended to indicate the presence of features, values, steps, operations, components, parts, or combinations thereof described in the specification. However, it should be understood that these terms do not preclude the presence or addition of one or more features, values, steps, operations, components, parts, or combinations thereof.

[0042] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms commonly used in dictionaries and already in dictionaries should be interpreted as having the meaning corresponding to their contextual meaning in this field. In this specification, unless explicitly defined, terms are not necessarily to be interpreted as having a formal meaning.

[0043] The forms or embodiments of the invention are described in detail below with reference to the accompanying drawings. In describing the embodiments, for ease of full understanding of the invention, the same reference numerals refer to the same elements throughout the description of the drawings. Repeated descriptions thereof have been omitted.

[0044] The following describes a wireless communication system employing an embodiment of the present invention. The wireless communication system employing an embodiment of the present invention is not limited to the following description, and embodiments of the present invention can be applied to various wireless communication systems. The wireless communication system may be referred to as a "wireless communication network".

[0045] Figure 1 This is a block diagram illustrating a first embodiment of a communication node constituting a wireless local area network system.

[0046] like Figure 1 As shown, communication node 100 can be an access point, a station, an access point (AP) multi-link device (MLD), or a non-AP MLD. An access point can refer to an AP, and a station can refer to a STA or a non-AP STA. The operating channel width supported by the access point can be 20 MHz, 80 MHz, 160 MHz, etc. The operating channel width supported by the station can be 20 MHz, 80 MHz, etc.

[0047] Communication node 100 may include at least one processor 110, memory 120, and multiple transceivers 130 connected to a network to perform communication. Transceivers 130 may be referred to as transceivers, radio frequency (RF) units, RF modules, etc. Furthermore, communication node 100 may further include input interface devices 140, output interface devices 150, storage devices 160, etc. Components included in communication node 100 can be connected to each other via bus 170 to communicate.

[0048] However, the individual components included in communication node 100 can be connected via separate interfaces or a separate bus centered on processor 110 instead of the common bus 170. For example, processor 110 can be connected via a dedicated interface to at least one of memory 120, transceiver 130, input interface device 140, output interface device 150, or storage device 160.

[0049] Processor 110 can execute at least one instruction stored in at least one of memory 120 or storage device 160. Processor 110 may refer to a central processing unit (CPU), graphics processing unit (GPU), or dedicated processor that performs the methods according to embodiments of the present invention. Memory 120 and storage device 160 may each be configured as at least one volatile storage medium and at least one non-volatile storage medium. For example, memory 120 may be configured with at least one read-only memory (ROM) or random access memory (RAM).

[0050] Figure 2 This is a conceptual diagram illustrating a first implementation of multiple links configured between MLDs.

[0051] like Figure 2 As shown, an MLD can have a Medium Access Control (MAC) address. In an implementation, an MLD can refer to an AP MLD and / or a non-AP MLD. The MAC address of the MLD can be used for the multi-link establishment process between the non-AP MLD and the AP MLD. The MAC address of the AP MLD can be different from the MAC address of the non-AP MLD. APs associated with an AP MLD can have different MAC addresses, and stations (STAs) associated with a non-AP MLD can have different MAC addresses. Each AP with a different MAC address can be responsible for each of the multiple links supported by the non-AP MLD and can act as an independent AP.

[0052] Each STA with a different MAC address can be responsible for each of the multiple links supported by a non-AP MLD and can perform the function of an independent STA. A non-AP MLD can be referred to as a STA MLD. An MLD can support Simultaneous Transmit and Receive (STR) operations. In this case, the MLD can perform a transmit operation on link 1 and a receive operation on link 2. An MLD that supports STR operations can be referred to as a STR MLD (e.g., a STR AP MLD, a STR non-AP MLD). In implementations, a link can refer to a channel or frequency band. A device that does not support STR operations can be referred to as a non-STR (NSTR) AP MLD or an NSTR non-AP MLD (or an NSTR STA MLD).

[0053] MLDs can transmit and receive frames across multiple links (i.e., multi-link) by utilizing discontinuous bandwidth extension schemes (e.g., 80 MHz + 80 MHz). Multi-link operation can include multi-band transmission. An AP MLD can include multiple APs, and these APs can operate on different links. Each of the multiple APs can perform the functions of a lower-level MAC layer. Each of the multiple APs can be referred to as a "communication node" or a "lower-level entity." A communication node (i.e., an AP) can operate at a higher-level layer (or...) Figure 1 The processor 110 shown operates under the control of the processor. A non-AP MLD may include multiple STAs, and these STAs may operate on different links. Each of the multiple STAs may be referred to as a "communication node" or a "lower-level entity." A communication node (i.e., a STA) may operate at a higher-level layer (or...) Figure 1 It operates under the control of the processor 110 shown.

[0054] MLDs can perform communication across multiple frequency bands (i.e., multi-band). For example, an MLD can perform communication using 40 MHz of bandwidth in the 2.4 GHz band according to a channel extension scheme (e.g., a bandwidth extension scheme), and can perform communication using 160 MHz of bandwidth in the 5 GHz band according to a channel extension scheme. An MLD can also perform communication using 160 MHz of bandwidth in the 5 GHz band and 160 MHz of bandwidth in the 6 GHz band. A frequency band (e.g., a channel) utilized by an MLD can be defined as a link. Alternatively, multiple links can be configured in a frequency band utilized by an MLD. For example, an MLD can configure one link in the 2.4 GHz band and two links in the 6 GHz band. These links can be referred to as Link 1, Link 2, and Link 3. Alternatively, these links can be referred to as Link 1, Link 2, and Link 3. Link numbers can be set by the AP, and identifiers (IDs) can be assigned to each link.

[0055] Multilink operations (MLDs) (e.g., AP MLDs and / or non-AP MLDs) can be configured to use multiple links by performing access and / or negotiation procedures for multilink operation. In this case, the number and / or links utilized in the multilink operation can be configured. A non-AP MLD (e.g., a STA) can identify information about the frequency bands that can communicate with the AP MLD. During the negotiation process for multilink operation between the non-AP MLD and the AP MLD, the non-AP MLD can configure one or more links supported by the AP MLD for multilink operation. Stations that do not support multilink operation (e.g., IEEE 802.11a / b / g / n / ac / ax STAs) can connect to one or more links in the multilink operation supported by the AP MLD.

[0056] When the bandwidth spacing between multiple links is sufficient (e.g., the bandwidth spacing between link 1 and link 2 in the frequency domain), the MLD can perform STR operations. For example, the MLD can use link 1 to transmit Physical Layer Convergence Procedure (PLCP) Protocol Data Unit (PPDU) 1 and use link 2 to receive PPDU 2. On the other hand, if the MLD performs STR operations when the bandwidth spacing between multiple links is insufficient, in-device coexistence (IDC) interference will occur, i.e., interference between multiple links. Therefore, when the bandwidth spacing between multiple links is insufficient, the MLD may not be able to perform STR operations. The link pairs with the above-mentioned interference relationship can be Non-Simultaneous Transmit and Receive (NSTR) restricted link pairs. Here, the MLD can be an NSTR AP MLD or an NSTR non-AP MLD.

[0057] For example, multiple links, including Link 1, Link 2, and Link 3, can be configured between the AP MLD and non-AP MLD 1. If the bandwidth spacing between Link 1 and Link 3 is sufficient, the AP MLD can perform STR operations using Link 1 and Link 3. In other words, the AP MLD can transmit frames using Link 1 and receive frames using Link 3. If the bandwidth spacing between Link 1 and Link 2 is insufficient, the AP MLD may not be able to perform STR operations using Link 1 and Link 2. If the bandwidth spacing between Link 2 and Link 3 is insufficient, the AP MLD may not be able to perform STR operations using Link 2 and Link 3.

[0058] On the other hand, in a wireless LAN system, a negotiation process for multi-link operation can be performed during the access process between the STA and the AP.

[0059] A device that supports multiple links (e.g., an AP or a STA) can be called a multi-link device (MLD). An AP that supports multiple links can be called an AP MLD, and a STA that supports multiple links can be called a non-AP MLD or a STA MLD. An AP MLD can have a physical address (e.g., a MAC address) for each link. An AP MLD can be implemented as if it were a separate AP responsible for each link. Multiple APs can be managed within a single AP MLD. Therefore, cooperation between multiple APs belonging to the same AP MLD is possible. Similarly, a STA MLD can have a physical address (e.g., a MAC address) for each link. A STA MLD can be implemented as if it were a separate STA responsible for each link. Multiple STAs can be managed within a single STA MLD. Therefore, cooperation between multiple STAs belonging to the same STA MLD is possible.

[0060] For example, AP1 of the AP MLD and STA1 of the STA MLD can each be responsible for the first link and can communicate using the first link. AP2 of the AP MLD and STA2 of the STA MLD can each be responsible for the second link and can communicate using the second link. STA2 can receive state change information from the first link in the second link. In this case, the STA MLD can collect information received from each link (e.g., state change information) and can control the operations performed by STA1 based on the collected information.

[0061] Figure 3 This is a sequence diagram illustrating a first implementation of the negotiation process for multi-link operation in a wireless local area network system.

[0062] like Figure 3 As shown, the access process between a STA and an AP in a basic service set (BSS) can generally be divided into a detection step to detect the AP, an authentication step to authenticate between the STA and the detected AP, and an association step to associate between the STA and the authenticated AP.

[0063] During the detection step, the STA can detect one or more APs using either a passive scanning scheme or an active scanning scheme. When using a passive scanning scheme, the STA can detect one or more APs by listening to beacons sent by one or more APs. When using an active scanning scheme, the STA can send probe request frames and can detect one or more APs by receiving probe response frames (responses to probe request frames) from one or more APs.

[0064] When one or more access points (APs) are detected, the STA can perform authentication steps with the detected APs. In this case, the STA can perform authentication steps with multiple APs. Authentication algorithms according to the IEEE 802.11 standard can be categorized into open system algorithms that exchange two authentication frames, shared key algorithms that exchange four authentication frames, etc.

[0065] The STA can send authentication request frames based on the authentication algorithm according to the IEEE 802.11 standard. The STA can also complete authentication with the AP by receiving authentication response frames (which are responses to the authentication request frames) from the AP.

[0066] Once authentication with the AP is complete, the STA can perform the association steps with the AP. Specifically, the STA can select an AP from the APs for which it has already performed authentication steps, and can then perform the association steps with the selected AP. In other words, the STA can send an association request frame to the selected AP, and can complete the association with the AP by receiving an association response frame (which is a response to the association request frame) from the selected AP.

[0067] On the other hand, multi-link operation can be supported in a wireless LAN system. A multi-link device (MLD) can include one or more STAs associated with the MLD. The MLD can be a logical entity. MLDs can be divided into AP MLDs and non-AP MLDs. Each STA associated with an AP MLD can be an AP, and each STA associated with a non-AP MLD can be a non-AP STA. To configure multi-link, a multi-link discovery process, a multi-link establishment process, etc., can be performed. The multi-link discovery process can be performed during the probe step between the STA and the AP. In this case, the multi-link information element (MLIE) can be included in the beacon frame, probe request frame, and / or probe response frame.

[0068] For example, to perform multi-link operation, during the probing step, an AP (e.g., an AP associated with an MLD) can exchange information with a STA (e.g., a non-AP STA associated with an MLD) indicating whether multi-link operation is available, as well as information about available links. During the multi-link operation negotiation process (e.g., the multi-link establishment process), the STA can send link information to be used for the multi-link operation. The multi-link operation negotiation process can be performed during the access process between the STA and the AP (e.g., the association step), and the information elements required for multi-link operation can be configured or changed via action frames during the negotiation process.

[0069] Furthermore, during the access process between the STA and AP (e.g., the association step), the available links of the AP can be configured, and an identifier (ID) can be assigned to each link. Subsequently, during the negotiation and / or change process of multi-link operation, information indicating whether each link is active can be sent, and the link ID can be used to represent the information.

[0070] During the exchange of performance information elements (e.g., EHT performance information elements) between the STA and AP, information indicating whether multi-link operation is available can be sent and received. Performance information elements may include information about supported frequency bands, information about supported links (e.g., the ID and / or number of supported links), and information about links capable of simultaneous transmit and receive (STR) operations (e.g., information about the frequency band of the links, information about the spacing between links), etc. Furthermore, performance information elements may include information specifically indicating which links are capable of STR operations.

[0071] Figure 4a This is a timing diagram illustrating a first embodiment of a channel access method in a multi-link wireless local area network system. Figure 4b This is a timing diagram illustrating a second embodiment of a channel access method in a wireless local area network system that supports multiple links.

[0072] like Figure 4a and Figure 4b As shown, when the bandwidth spacing between multiple links is sufficient, transmission operations in the first link and reception operations in the second link can be performed simultaneously. Transmission operations utilizing multiple links can be implemented with independent transmission schemes for each link. These transmission operations can be performed in devices capable of supporting STR operations (e.g., AP or STA). In other words, these transmission operations can be performed on link pairs other than NSTR-restricted link pairs.

[0073] When using an independent transmission scheme, lower-level layers (e.g., the physical (PHY) layer and / or the MAC layer) can perform channel access operations independently in each link (e.g., the first link and the second link) to transmit frames (e.g., PDUs) obtained from the upper-level layer. When a transmission opportunity (TXOP) is secured through a channel access operation, the lower-level layer can transmit frames within the corresponding TXOP.

[0074] Channel access operations can be carrier sensing operations performed within the Arbitration Interframe Space (AIFS) based on the data included in the frame (e.g., the data's access category (AC)). A carrier sensing operation can be referred to as a "channel sensing operation." Channel access operations can include carrier sensing operations and backoff operations within the AIFS when a carrier sensing operation determines that the channel (e.g., a link) is busy or when the transmission of a data frame from another station has completed.

[0075] Carrier sensing operations can be categorized into physical (PHY layer) carrier sensing operations and virtual carrier sensing operations. Physical carrier sensing operations can be energy detection (ED) operations that sense the received power in the operational channel (e.g., operational link). Virtual carrier sensing operations can include setting operations based on the value of the length field contained in the preamble of a frame received from another station (e.g., PPDU or MPDU) and network allocation vector (NAV) setting operations based on the value of the duration field or TXOP field in the MAC header of a frame received from another station. NAV setting operations can involve setting parameters to configure a transmission prohibition period or to configure a transmission prohibition period as a time when a terminal has not started transmission (i.e., the time when another terminal performs a transmission operation). Transmission time can be independent of the physical channel sensing results. NAV setting operations can also involve setting a period (e.g., a busy period) during which frame transmission is prohibited by the value of the duration field contained in the MAC header of frames transmitted by terminals within and / or outside the Basic Service Set (BSS). When virtual carrier sensing is successful and NAV is set, the time period set by NAV can be designated as a busy period, and actual carrier sensing will not be performed.

[0076] When using an independent transmission scheme, the transmission times of frames in links (e.g., link 1 and link 2) may not match. Since channel access operations in each link are performed independently, the links can be utilized efficiently. In implementations, a backoff operation (e.g., a backoff procedure, a random backoff operation) can refer to a channel access procedure performed when the channel state is determined to be busy.

[0077] On the other hand, when the bandwidth spacing between multiple links is insufficient, transmission operations in the first link can interfere with the second link of the same device. This interference can be intra-device coexistence interference (IDC). In embodiments, "device" can refer to an MLD, AP, and / or STA. When such IDC interference occurs, STR operations may not be possible on multiple links. Link pairs that cannot perform STR operations can be referred to as "NSTR-restricted link pairs." For example, when a device utilizes two links operating in the 5 GHz band (e.g., the first and second links), if the bandwidth between the links is insufficient, it may not be possible to simultaneously perform a transmission operation on the first link and a reception operation on the second link. Therefore, multi-link operation cannot be implemented with an independent transmission scheme for each link. In this case, multi-link operation can be implemented with a synchronous transmission scheme. In embodiments, multi-link operation can refer to the use of multiple links for transmission / reception operations.

[0078] When a transmission event occurs, the device can perform channel connection operations. For example, the device can identify the channel occupancy status, and when the channel status is idle, the device can perform additional channel listening operations within a specific time period (e.g., AIFS). When the channel status is idle within the specific time period, the device can finally determine that the channel is idle. In other words, the device can determine that channel access is successful. In this case, backoff operations may not be performed, and the backoff counter value can be 0.

[0079] On the other hand, when the channel state is busy (e.g., occupied), the device can wait until the channel state becomes idle. When the channel state changes from busy to idle, the device can perform a backoff operation after waiting for AIFS. AIFS can start from the time the channel state changes from busy to idle. When the backoff operation is successfully completed, the device can transmit a frame.

[0080] When performing a backoff operation, the device can select any value from 0 to the contention window (CW) (e.g., a backoff counter value). The CW can be set differently depending on the access class (AC) of the data. The device can perform channel listening operations in the time slots corresponding to the selected backoff counter value. For example, when the backoff counter value is 5, the device can perform channel listening operations in 5 time slots (e.g., time slots 1 to 5).

[0081] A channel listening operation can be performed in each time slot, and the backoff counter value can be decremented by 1 when the channel listening operation is successful in each time slot. When the channel state in time slot 1 is determined to be idle as a result of the channel listening operation in time slot 1, the backoff counter value can be set to 4 (e.g., 5-1). When the channel state in time slot 2 (following time slot 1) is determined to be idle as a result of the channel listening operation, the backoff counter value can be set to 3 (e.g., 4-1). When the channel state in time slot 5 (the last time slot) is determined to be idle as a result of the channel listening operation, the backoff counter value can be set to 0 (e.g., 1-1). When the backoff counter value becomes 0, the device can determine that the backoff operation was successful.

[0082] When a channel access operation is successful but no transmission event occurs, the device can wait for the transmission of a frame (e.g., data). Subsequently, when a transmission event occurs, since the channel access operation has been successful, the device can immediately transmit the frame without a backoff operation. In other words, when the backoff counter value remains at 0, the device can transmit the frame without a backoff operation.

[0083] When using a synchronous transmission scheme, the start and / or end times of transmission for frames transmitted on each link can be set identically. To ensure consistent frame transmission times in multi-link operations based on a synchronous transmission scheme, if the lengths of frames transmitted on different links differ, padding bits can be added to frames with shorter lengths to match the frame lengths. When performing a simultaneous transmission channel access operation, a backoff operation is performed on the first link, and the channel state of the second link is idle from a specific time until the end time of the backoff operation on the first link (e.g., the success time), the apparatus can perform transmission operations using multiple links (e.g., the first and second links). The time from the specific time to the end time of the backoff operation on the first link can be the point coordination function (PCF) inter-frame interval (PIFS), the distributed coordination function (DCF) inter-frame interval (DIFS), AIFS, or the total time of the backoff operation on the first link.

[0084] "Identifying the channel occupancy status of the second link during the period from a specific time to the end time of the backoff operation in the first link" can be used to "identify whether the channel occupancy status of the second link is in an idle state where frame transmission can take place." In other words, "identifying the channel occupancy status of the second link during the period from a specific time to the end time of the backoff operation in the first link" can mean "performing a channel sensing operation (e.g., a carrier sensing operation) in the second link during the period from a specific time to the end time of the backoff operation in the first link."

[0085] To perform simultaneous transmission using both the first and second links, a channel access operation can be performed. In this case, the channel access operation can be performed simultaneously on both the first and second links. If the second link is idle at the start time of the channel access operation, and this idle state is maintained for a specific time (e.g., AIFS), the device can determine that the second link is idle. In this case, since a backoff operation can be omitted on the second link, its backoff counter value can be 0. Here, a link other than the first link can be configured as the second link.

[0086] On the other hand, after the backoff operation in the first link ends, the operation of identifying the channel occupancy status can be performed in the second link within a specific time period. When the channel state of the second link is busy for some time within the specific time period, the device can transmit frames using only the first link. Alternatively, the device can perform a backoff operation in the second link. Alternatively, the device can perform a backoff operation in multiple first links for channel access. Multiple first links can be configured, and backoff operations can be performed in multiple first links. In this case, when the channel state of the second link is idle during the time period from the end time of the backoff operation in the link where the backoff operation is first completed to the time before the specific time (hereinafter referred to as the "specific time period") (e.g., PIFS, DIFS, AIFS, or the total time of the backoff operation in the first link), the device can perform transmission operations using multiple links.

[0087] "Identifying whether another link is idle within a specific time period" can mean "identifying whether a link is in an idle state where frame transmission is possible." "Identifying whether another link is idle within a specific time period" can also mean "performing a channel sensing operation (e.g., carrier sensing operation) within a specific time period from the end of the backoff operation in the first link to the time preceding that specific time." To perform simultaneous transmission using the first link and other links, a channel access operation can be performed. In other words, when a channel access operation begins in the first link, channel access operations can begin simultaneously in other links. When there is an idle link at the start time of the channel access operation and that link remains idle for a specific time period (e.g., AIFS), the corresponding link can be identified as a link capable of simultaneous transmission. Since links idle at the start of the channel access operation do not perform backoff operations, the backoff counter value can be 0 in idle links.

[0088] When performing multi-link operation based on a synchronous transmission scheme, the receiving device (e.g., STA or AP) can receive multiple frames simultaneously. This simplifies frame reception operations. Frames (e.g., data) transmitted in a synchronous transmission scheme can include information about the links used for simultaneous transmission. This information (e.g., link ID, etc.) can be indicated in bitmap form by an EHT signal (SIG) that includes information about the IEEE 802.11be signal in the preamble of the PPDU. Alternatively, the information about the links used for simultaneous transmission (e.g., link ID, etc.) can be indicated by an EHT control field included in the frame.

[0089] Figure 5 This is a timing diagram illustrating a first embodiment of a method for updating parameters in a wireless local area network system that supports multiple links.

[0090] like Figure 5 As shown, a non-STR STA can refer to an STA that cannot simultaneously perform a transmit operation on the first link and a receive operation on the second link. Due to interference caused by the transmit operation on the first link, the receive operation on the second link may not be performed. A non-STR STA can also be an STA that cannot perform STR operations on NSTR-restricted link pairs (which are specific link pairs based on performance). Alternatively, a non-STR STA can be an STA that cannot perform STR operations regardless of the link pair.

[0091] A STA MLD may include STA1, which is responsible for the first link, and STA2, which is responsible for the second link. An AP MLD may include AP1, which is responsible for the first link, and AP2, which is responsible for the second link. Communication between STA1 and AP1 can be performed using the first link, and communication between STA2 and AP2 can be performed using the second link. A STA MLD may be a non-STR STA MLD that cannot perform STR operations. STA1 in a non-STR STA MLD may not occupy the first link if the first link is busy, and STA2 in a non-STR STA MLD may utilize the second link to send PPDU1 in the second link if the second link is available (e.g., because the second link is idle).

[0092] When the parameters of AP1 responsible for the first link in the communication parameters applied to each BSS (e.g., each AP in the AP MLD) change (e.g., Basic Service Set (BSS) parameters), AP1 in the AP MLD can send a beacon frame (or probe response frame) in the first link that includes the changed parameters. Furthermore, the beacon frame (or probe response frame) may further include change sequence information, information indicating the target of the updated parameters (e.g., a specific AP, all APs included in the AP MLD, or a BSS), information indicating the time period for which the parameters are valid, and / or information indicating the area (e.g., BSS, geographic region) where the parameters are applied. When the parameters are updated, the change sequence information may indicate the value increased from the previous value (e.g., an increase of 1).

[0093] AP1 of the AP MLD can be responsible for the first link and can send beacon frames according to the transmission period. A beacon frame including updated parameters can be sent during the transmission of PPDU1 by STA2. STA1 of a STA MLD that does not support STR operation may not receive beacon frames from AP1. Therefore, the STA MLD (e.g., STA1 and / or STA2) may not update the changed parameters and may not utilize the changed parameters in the next communication process.

[0094] For example, since the updated parameters required for communication in the first link have not been received, STA1 may attempt to send a frame (e.g., a data frame) in the first link using unchanged parameters after the beacon frame's transmission and reception time. In this case, STA1's frame transmission may fail because it is using unchanged parameters. Even when STA1's frame is transmitted, AP1 may not receive (e.g., decode) STA1's frame because it is using changed parameters after the transmission time of the beacon frame that includes updated parameters. In other words, AP1's frame reception may fail. Because STA1 failed to update its parameters, it may not receive (e.g., decode) the frame transmitted by AP1 using changed parameters.

[0095] When STA1 of a STA MLD supporting STR operation is operating in power-saving mode, or when communication in a STA MLD supporting STR operation is performed on a second link without utilizing the first link, STA1 of the STA MLD may not receive beacon frames (or probe response frames) including updated parameters on the first link. In this case, after STA1's operating state changes from power-saving mode to normal mode, STA1 may be unable to communicate with AP1 without updated parameters.

[0096] The procedures for updating parameters (e.g., procedures 1, 2, and 3) are described in the following implementation. A combination of one or more of these procedures may be utilized.

[0097] Process 1 In process 1, in response to PPDU1 received from STA2, AP2 can send a response frame (e.g., an ACK frame or a block ACK (BA) frame) to STA2 via the second link. This response frame includes information indicating that parameters have changed (e.g., a critical update flag, an urgent update indicator, or a parameter change indicator). STA2 can also receive a response frame from AP2 via the second link that includes a critical update flag (e.g., an urgent update indicator or a parameter change indicator). The critical update flag can be an indicator indicating that a critical parameter of a specific link has changed. To indicate that the parameters of the AP responsible for a specific link or the parameters of the BSS under the corresponding AP's responsibility have changed, the identifier of the AP or BSS can be included in the corresponding frame along with the critical update flag. In an implementation, the critical update flag may refer to an urgent update indicator or a parameter change indicator.

[0098] A critical update flag can be included in another control frame and / or another management frame transmitted by AP2 on the second link. For example, AP2 may transmit a beacon frame, probe response frame, and / or another management frame that includes the critical update flag on the second link. STA2 can identify the critical update flag by receiving the beacon frame, probe response frame, and / or another management frame from AP2 on the second link. In this case, STA MLDs (e.g., STA1 and / or STA2) can determine, based on the critical update flag, that the parameters used for communication (e.g., parameters applied to the first link) have changed. Therefore, STA MLDs can stop or wait for transmission operations on the first and / or second links. STA MLDs supporting STR operations can perform transmission operations on the second link.

[0099] After receiving a key update flag included in a frame in the second link, STA2 can receive a frame from AP2 in the second link that includes changed parameters (e.g., updated parameters). The frame including the changed parameters can be an unsolicited probe response frame. An unsolicited probe response frame can be a probe response frame sent without a probe request frame. Alternatively, the frame including the changed parameters can be a probe response frame that is a response to a probe request frame sent by another communication node (e.g., STA).

[0100] After sending a BA or ACK frame on the second link, an active probe response frame can be sent unicast on the first and / or second link. In other words, the destination address of the active probe response frame can indicate a specific STA (e.g., STA2). When a probe response frame (e.g., an active probe response frame) including changed parameters is sent on the second link, information indicating that the changed parameters apply to the first link (e.g., link identifier or AP identifier (e.g., AP ID or BSS ID)) can be included in the probe response frame. The probe response frame can be broadcast, allowing another communication node (e.g., an STA without updated parameters) to listen for probe response frames including changed parameters.

[0101] When a critical update flag is received on the second link, a non-STR STA MLD can send a probe request frame on the first and / or second link to receive a probe response frame that includes updated parameters. The probe request frame sent on the second link may include information requesting the sending of updated parameters for the first link (e.g., link identifier or AP identifier (e.g., AP ID or BSS ID)).

[0102] AP MLD can send beacon frames that include updated parameters instead of probe response frames (e.g., active probe response frames). Beacon frames may only include updated parameters. Updated parameters can be sent on the first and / or second link. Available links among the supported links can be utilized to send updated parameters.

[0103] Process 2 Process 2 can be executed independently. Alternatively, process 2 can be executed together with one or more operations of process 1. When process 2 is executed independently, since the AP MLD can identify that the beacon frame including the updated parameters is being transmitted simultaneously with STA2 transmitting PPDU1, and can identify that STA1 and STA2 did not receive the updated parameters because STA1 and STA2 of the STA MLD do not support STR operations, the AP MLD can still perform the reception operation (e.g., decoding operation) of the frame (e.g., PPDU2) transmitted by STA1 of the STA MLD using the unchanged parameters even after the transmission of the beacon frame. Here, the frame of the STA MLD may be the frame first transmitted in the first link after the time of transmitting and receiving the beacon frame including the updated parameters. The period during which frames cannot be received in the first link due to the transmission of PPDUs in the second link can be called a "deaf period". As a method for the AP MLD to perform the reception operation of PPDU2 using the unchanged parameters, the AP MLD can identify the STA (e.g., STA1) of the STA MLD that did not receive the beacon frame including the updated parameters during the deaf period. AP MLD can also receive (e.g., decode) PPDUs sent by the corresponding STA using the previous parameters until the next beacon frame with updated parameters is sent. As another method for AP MLD to perform the reception operation of PPDU2 using the unchanged parameters, AP MLD can receive (e.g., decode) PPDU2 sent by STA1 using the parameters before the update if it fails to receive (e.g., decode) PPDU2 using the updated parameters (e.g., when a CRC check error occurs).

[0104] The AP MLD can generate a response frame (e.g., ACK or NACK) that includes a response to the frame received by the STA MLD and a key update flag (e.g., BA or ACK frame), and can send the response frame to the STA MLD (e.g., STA1). The STA MLD (e.g., STA1) can receive the response frame for PPDU2 from the AP MLD (e.g., AP1) and can identify that the parameters have changed based on the key update flag included in the response frame.

[0105] After sending the critical update flag, the AP MLD (e.g., AP1) can send a probe response frame (e.g., an active probe response frame) and / or a beacon frame that includes the updated parameters. The probe response frame and / or beacon frame that includes the updated parameters can be sent on the first link and / or the second link. The transmission / reception operation of the probe response frame and / or beacon frame that includes the updated parameters in process 2 can be performed in the same or similar manner as the transmission / reception operation of the probe response frame and / or beacon frame that includes the updated parameters in process 1 described above.

[0106] Process 3 Process 3 can be performed after sending and receiving frames including key update flags (e.g., BA frames or ACK frames including key update flags) in Process 1 and / or Process 2. The AP MLD (e.g., AP1) can send beacon frames including updated parameters. Beacon frames can be sent in the first link. The STA MLD (e.g., STA1) can receive beacon frames from the AP MLD and identify the updated parameters included in the beacon frames. Beacon frames can be sent / received during a pre-configured beacon transmission period (e.g., target beacon transmission time (TBTT)). The STA MLD can update the parameters based on the information included in the beacon frames and can use the updated parameters to perform the transmission / reception of frames (e.g., data frames).

[0107] If STA2 of the STA MLD does not perform a transmission operation on the second link during the next beacon transmission period, STA1 of the STA MLD can receive beacon frames including updated parameters on the first link. Therefore, the STA MLD can set a self-network allocation vector (NAV) for the next beacon transmission period. The self-NAV setting operation can be performed as follows: within a predetermined reception period on the current link (e.g., the first link), set parameters or a transmission prohibition period that prohibits its own transmission on another link (e.g., the second link) that may interfere with the current link (e.g., the first link). The self-NAV can be used to ensure reception of beacons including updated parameters on the first link. When the NAV for the next beacon transmission period is set, STA1 of the STA MLD can receive beacon frames on the first link.

[0108] Whether to set up self-NAV can also be indicated by the AP MLD. AP1 or AP2 of the AP MLD can send a self-NAV operation indication information element as an indication to set up self-NAV, so that no transmission is performed on the second link, while AP1 of the AP MLD sends a beacon frame including updated parameters on the first link. The self-NAV operation indication information element may include information about a "quiet period" and information about the identifier of the AP, channel, or BSS to which the self-NAV operation is targeted. The self-NAV operation indication information element may be included in the beacon frame or probe response frame sent by AP1 or AP2 of the AP MLD. The quiet period can be replaced by a "do-not-transmit" indicator or information element. The terminal to which the self-NAV operation is targeted can be any terminal operating on the link or channel to which the self-NAV operation is targeted, as indicated by the self-NAV operation indication information element.

[0109] When a beacon frame includes information indicating the beacon transmission interval, the start time of the self-NAV can be after the beacon transmission interval from the reception time of the last beacon frame. When a beacon frame does not include information indicating the beacon transmission interval, STAMLD can estimate the beacon transmission interval based on multiple beacon frames received from the AP MLD and can set the self-NAV for another link based on the estimated beacon transmission interval. When a beacon frame is received from the AP MLD in the first link, STAMLD can release the self-NAV set in the second link. When there are frames to be received in the first link and beacon frames, the self-NAV can be set in a link belonging to an NSTR link pair with the first link (e.g., the second link).

[0110] The critical update flag can be 1 bit in size. The critical update flag indicates whether a parameter has changed on any of multiple links. In other words, the critical update flag indicates whether a parameter has changed on which link among multiple links. The critical update flag can indicate the existence of a changed parameter via a change sequence. The critical update flag can be associated with a change sequence. The change sequence can be called a "change counter." Each time a parameter changes, the change sequence (i.e., the value of the change sequence) can increment. The change sequence can indicate the version of the parameter. An AP identifier or BSS identifier can be included in the frame along with the critical update flag. An AP identifier or BSS identifier can be included to indicate which link's parameter has changed. In other words, since an AP is assigned (mapped) to each link and that AP is responsible for a BSS, the link can be identified by the AP identifier or BSS identifier.

[0111] The AP MLD can send a critical update flag on the second link and can send beacon frames and / or probe response frames including a change sequence on the first link. When parameters change, the value of the change sequence can increase compared to the value of a previous change sequence (e.g., a change sequence associated with unchanged parameters). The critical update flag can include information indicating that its parameters have changed (e.g., link identifier, AP identifier, BSS identifier).

[0112] When a critical update flag is received in the second link (e.g., when the critical update flag indicates that a parameter has changed), the STA MLD can obtain the change sequence by receiving beacon frames and / or probe response frames in the first link. Upon receiving the change sequence from the AP MLD, the STA MLD can compare the received change sequence with the change sequence stored in the STA MLD and determine whether the parameter has changed based on the comparison result. For example, if the received change sequence is the same as the change sequence stored in the STA MLD, the STA MLD can determine that the parameter has not changed. When the received change sequence is different from the change sequence stored in the STA MLD, the STA MLD can determine that the parameter has changed. In this case, the STA MLD can perform a parameter update operation based on the parameters received from the AP MLD.

[0113] The AP MLD can send information indicating changed parameters to the STA MLD. In this case, the STA MLD can perform an update operation on the specific parameters indicated by the AP MLD. Parameter types can include: Enhanced Distributed Channel Access (EDCA) parameters, High Throughput (HT) operating parameters, Very High Throughput (VHT) operating parameters, High Efficiency (HE) operating parameters, Extremely High Throughput (EHT) operating parameters, Direct Sequence Spread Spectrum (DSS) parameter sets, etc. When the AP MLD indicates that the EHT operating parameters have changed, the STA MLD can perform an update operation on the EHT operating parameters.

[0114] On the other hand, the STA MLD can configure the first link as the primary link, and STA1 of the STA MLD can be configured to perform beacon frame reception operations in the first link. In this case, if STA1 of the STA MLD does not support STR operations, it can set up a self-NAV in the second link during the preset beacon transmission time period (TBTT) in the first link. Since no frame transmission operations are performed in the second link with the self-NAV set, STA1 of the STA MLD can receive beacon frames in the first link. STA2 of the STA MLD, which performs transmission operations in the second link, can adjust the length of the PPDU so that the transmission operation terminates before the start time of the self-NAV. When beacon frame reception is scheduled in the first link and the self-NAV setting is scheduled for the second link for beacon frame reception in the first link, STA2 of the STA MLD can successfully perform channel access operations (e.g., channel listening operations, backoff operations) in the second link before the start time of the self-NAV. In this case, after the STA MLD successfully performs channel access operations for PPDU transmission in the second link, the STA MLD can wait for PPDU transmission until the self-NAV terminates without PPDU transmission. After receiving a beacon frame in the first link, STAMLD can immediately begin transmission operations in the second link without having to perform channel access operations again.

[0115] Figure 6 This is a block diagram illustrating a first embodiment of a BA frame, which includes information indicating whether parameters have changed.

[0116] like Figure 6As shown, a critical update flag (e.g., information indicating whether parameters have changed) can be indicated by information included in the header of the BA frame. For example, the value of the duration field included in the header can be set to be longer than the transmission time of the corresponding BA frame. A duration field indicating a time longer than the transmission time of the BA frame can indicate that parameters have changed. In other words, the duration field can be used as a critical update flag and can indicate that a frame including the changed parameters should be sent after the BA frame is sent. A time longer than the transmission time of the BA frame (e.g., the value of the duration field) can be set to "the transmission time of the BA frame + the shortest inter-frame interval (SIFS) + the transmission time of the frame including the changed parameters". Alternatively, a time longer than the transmission time of the BA frame (e.g., the value of the duration field) can be set to be less than or equal to "the transmission time of the BA frame + 1 slot time". In this case, additional channel contention operations can be performed for the transmission of the frame including the changed parameters. TID information can be used to indicate links whose parameters have changed. Since TIDs are mapped to links, links mapped to TIDs can be identified based on the mapping relationship between TIDs and links. Here, a link's parameters have changed. Alternatively, AP identifiers, BSS identifiers, or link identifiers can be inserted and transmitted by placing additional information elements in the BA information.

[0117] Alternatively, reserved bits in the BA frame (e.g., BA control fields included in the BA frame) can be configured as critical update flags. One reserved bit in the BA frame can be used, in which case one reserved bit can indicate whether a parameter has changed. Alternatively, multiple reserved bits in the BA frame can be used, in which case multiple reserved bits can indicate the changed parameters. Multiple reserved bits can be configured in the form of a bitmap. For example, when using three reserved bits, the first reserved bit can indicate whether VHT operating parameters have changed, the second reserved bit can indicate whether HE operating parameters have changed, and the third reserved bit can indicate whether EHT operating parameters have changed. Links with changed parameters can be identified based on identifiers included in the TID or BA information (e.g., AP identifier, BSS identifier, or link identifier).

[0118] Figure 7 This is a block diagram illustrating a first embodiment of an ACK frame, which includes information indicating whether parameters have changed.

[0119] like Figure 7As shown, a critical update flag (e.g., information indicating whether parameters have changed) can be indicated by information included in the header of the ACK frame. For example, the value of the duration field included in the header can be set to be longer than the transmission time of the corresponding ACK frame. A duration field indicating a time longer than the transmission time of the ACK frame can indicate that parameters have changed. In other words, the duration field can be used as a critical update flag and can indicate that a frame including the changed parameters should be sent after the ACK frame. The time longer than the transmission time of the ACK frame (e.g., the value of the duration field) can be set to "the transmission time of the ACK frame + SIFS + the transmission time of the frame including the changed parameters". Alternatively, the time longer than the transmission time of the ACK frame (e.g., the value of the duration field) can be set to be less than or equal to "the transmission time of the ACK frame + 1 time slot". In this case, an additional channel access operation can be performed for the transmission of the frame including the changed parameters. In the case of the ACK frame, the transmission time indicating parameter changes can be set differently for each link so that the link can be identified. For example, if the number of supported links is four, the time can be increased as a result of an operation (incrementing the time modulo 4).

[0120] Figure 8 This is a timing diagram illustrating a second embodiment of a method for updating parameters in a multi-link wireless local area network system.

[0121] like Figure 8 As shown, when a STAMLD that does not support STR operations performs a transmission operation on a link, a beacon frame (hereinafter referred to as an "update beacon frame") including changed parameters can be transmitted after the aforementioned transmission operation. A transmission operation can be performed on a second link, and the update beacon frame can be sent / received on the first link. In this case, the STAMLD can receive the update beacon frame on the first link after the transmission operation on the second link has ended.

[0122] The AP MLD may send an update beacon frame after a SIFS or Point Coordination Function (PCF) inter-frame interval (PIFS) starting from a specific time. Alternatively, the AP MLD may perform a backoff operation after a SIFS or PIFS starting from a specific time and may send the update beacon frame when the backoff operation is complete. In other words, the transmission of the update beacon frame can be delayed. The specific time may be the end time of the transmission operation of the STA MLD (e.g., STA2) in the second link (e.g., the time when the reception of the BA frame (or ACK frame) for PPUD1 is completed). The update beacon frame may have a higher priority than frames that have applied a longer time than SIFS or PIFS (e.g., DIFS or Arbitration Inter-Frame ...

[0123] If the transmission delay of a delayed update beacon frame is T2, and the time from the end of the transmission delay to the next beacon transmission period (TBTT) when the beacon frame is transmitted without transmission delay is T1, then the beacon transmission period (TBTT) of the delayed update beacon frame can be T1+T2. In this case, the TBTT (e.g., T1+T2) can be the time excluding the execution time of the channel access operation. Alternatively, since the transmission delay is only abnormal for the current update beacon frame, the TBTT indicated by the information included in subsequent beacon frames can be T2. In this case, a beacon frame following the delayed beacon frame can be transmitted quickly, and then that beacon frame can be transmitted according to the originally planned beacon transmission period.

[0124] AP MLDs can configure non-STR virtual NAVs to update beacon frame transmission delays. Since STA2 of an AP MLD that does not support STR operations performs STA MLD transmission operations on the second link while STA1 of the AP MLD cannot receive data on the first link, a non-STR virtual NAV can be configured to delay frame transmission to STA1 of the AP MLD on the first link during the corresponding time period. In other words, a non-STR virtual NAV can be used to ensure that during the time STA2 performs STA MLD transmissions on the second link, no frame transmissions to STA1 of the AP MLD occur on the first link. The non-STR virtual NAV can be configured on the first link based on frames (e.g., PPDU1) transmitted by STA2 of the AP MLD on the second link.

[0125] For example, STA2 of STA MLD can transmit PPDU1 on a second link, and AP2 of AP MLD can receive PPDU1 on the second link. AP MLD can identify during the initial access process that STA MLD does not support STR operation. Therefore, when PPDU1 is received from STA2 of STA MLD that does not support STR operation, AP MLD can set a non-STR virtual NAV to prevent the transmission of frames to the STA MLD's STA responsible for another link during the transmission time of PPDU1. AP MLD can identify that the STA transmitting PPDU1 does not support STR operation and the transmission time of PPDU1 based on the value of the duration field included in PPDU1, the address of the transmitter sending PPDU1, and / or the length value of the preamble. In this case, AP MLD can set a non-STR virtual NAV for the other STA of STA MLD responsible for other links for that duration. When the duration of PPDU1 includes the reception time of BA frames, a non-STR virtual NAV can be set only for the transmission time of PPDU1. The transmission time of PPDU1 can be identified based on the length parameter (e.g., 12 bits) included in the signal field of the preamble of PPDU1. When AP1 of APMLD sets a non-STR virtual NAV for STA1 of STA MLD in the first link, during the time period corresponding to the non-STR virtual NAV in the first link, AP1 of AP MLD can perform transmissions to other communication nodes but can choose not to perform transmission operations to STA1 of STA MLD. When a data packet to be sent to STA1 of STA MLD is generated during the time period in which the non-STR virtual NAV is set, the data packet can be transmitted after the end of the time period in which the non-STR virtual NAV is set. In other words, the transmission of data packets can be delayed.

[0126] A non-STR virtual NAV can be set for each STA in a STA MLD that does not support STR operations. The setting information for the non-STR virtual NAV can include the identifier of the STA with the applied NAV timer and / or non-STR virtual NAV (e.g., MAC address, association identifier (AID), etc.). For example, the non-STR virtual NAV for STA1 in the STA MLD can be set independently of the non-STR virtual NAV for STA2 in the STA MLD. When a non-STR virtual NAV is set, the following transmission operations can be prohibited for the STA with the applied non-STR virtual NAV during the corresponding time period.

[0127] - Unicast transmission operation: Transmission operation of frames with a receiver address (e.g., a destination address) indicating a STA with a non-STR virtual NAV configured.

[0128] - Multicast transmission operation: Transmission operation of frames with a receiver address (e.g., a destination address) indicating the multicast group to which a STA with a non-STR virtual NAV belongs.

[0129] - Broadcast transmission operation: Transmit all frames in a broadcast scheme.

[0130] Figure 9 This is a timing diagram illustrating a first implementation of a method for setting up a non-STR virtual NAV in a multi-link wireless LAN system.

[0131] like Figure 9 As shown, as a method for setting a non-STR virtual NAV for a STA MLD (e.g., STA1 of STR STA MLD2) or AP MLD (e.g., AP1 of AP MLD), a STA of a STA MLD that does not support STR operations (e.g., STA2 of STA MLD1) can set a non-STR virtual NAV in a STA responsible for another link (e.g., STA1 of STA MLD1) of the STA MLD that does not support STR operations, based on information included in the header of frames transmitted on a specific link (e.g., duration, transmitter address, preamble length value). When a non-STR virtual NAV is set, the STA MLD (e.g., STA1 of STR STA MLD2) or AP MLD (e.g., AP1 of AP MLD) can not perform frame transmission operations on the STA (e.g., STA1 of STA MLD1) that has the non-STR virtual NAV applied during the time period corresponding to the non-STR virtual NAV. In this case, there will be no conflict between frames transmitted by the STA MLD and other STAs associated with the STA that has the non-STR virtual NAV applied. For example, when a frame is transmitted in the second link, and when STR operations are not supported in both the first and second links, a non-STR virtual NAV can be set based on the value of the duration field, the transmitter address, and / or the length of the preamble included in the header of the frame transmitted in the second link, so that in the first link associated with the STA responsible for the first link in the STA MLD (e.g., the STA MLD associated with the STA corresponding to the transmitter address) that is transmitting the frame in the second link, the frame is not transmitted to the STA responsible for the first link in the STMLD for the duration or the length of the preamble.

[0132] When the first link is occupied, STA MLD1, which does not support STR operations, can transmit frames (e.g., PPDUs) on the second link. AP2 of AP MLD can receive frames from STA2 of STA MLD1 on the second link. AP MLD can identify STAMLD1 of STA2 based on the transmitter address of the frames transmitted by STA2 of STA MLD1 and the information registered at initial access. AP MLD can identify whether STA MLD1 supports STR functionality and / or whether the first link (i.e., STA1) and the second link (i.e., STA2) are an NSTR pair by referring to the performance registered by STA MLD1 in AP MLD. After identifying that STA MLD1 cannot perform STR operations on the first link (i.e., STA1) and the second link (i.e., STA2), AP MLD can set a non-STR virtual NAV based on the value of the duration field or the length of the preamble included in the header of the frames of STA1 of STA MLD1 received on the second link to prohibit the transmission of frames of STA1 of STA MLD1 within the duration or the length of the preamble.

[0133] A non-STR virtual NAV can be set together with another NAV (e.g., a normal NAV). AP1 of AP MLD can set a normal NAV in the first link and can set a non-STR virtual NAV independently of the normal NAV in the first link. A non-STR virtual NAV can be set for STA1 of STA MLD1 in the first link based on the value of the duration field or the length value of the preamble included in the header of the frame transmitted by STA2 of STA MLD1 in the second link.

[0134] If a frame (e.g., a PPDU) needs to be transmitted to STA MLD2 after the normal NAV ends, AP1 of AP MLD can send the frame to STA1 of STA MLD2 in the first link, even during the period when the non-STR virtual NAV is applied, since the non-STR virtual NAV is not applied to STA MLD2. Frames from STA MLD2 to STA1 can be transmitted according to channel contention operation. Frames of STA MLD1 can be transmitted after the non-STR virtual NAV applied to STA1 ends. For example, AP1 of AP MLD can perform channel contention operation in the first link after the non-STR virtual NAV ends. Furthermore, if the channel contention operation is successful, AP1 of AP MLD can send a frame (i.e., a PPDU of STA MLD1) to STA MLD1. When performing direct communication between STA MLDs (e.g., peer-to-peer (P2P) communication), other STAMLDs that receive frames from STA MLD1 can set the non-STR virtual NAV applied to STA MLD1.

[0135] If the information from previous registration does not identify whether STR operations or / and NSTR link pairs are supported, links with non-STR virtual NAVs can be identified based on the value of the duration field. Links that do not support STR operations can be identified based on the result of a modulo operation between the duration field value and the slot time. For example, a modulo operation can be performed on the duration field value and the slot time (e.g., 9 μs). The results of the modulo operation can be used to determine links with non-STR virtual NAVs applied, as shown in Table 1 below.

[0136] [Table 1] The length of a non-STR virtual NAV can be set to "the value of the duration field - the result of the modulo operation". For example, when the time slot time is 9 μs and the value of the duration field is 452 μs, since the result of (452 ​​mod 9) is 2, STR operations may not be supported in link #1 (e.g., the first link). Therefore, a non-STR virtual NAV can be set in link #1, in which case the length of the non-STR virtual NAV can be 450 μs.

[0137] When the number of available links in the AP MLD is four or fewer, a bitmap can be used to indicate whether a non-STR virtual NAV is set on each link that does not perform transmission. For example, the STA MLD can transmit a frame on link #2, and the value of the duration field included in the frame can be 453 μs. In this case, since the result of (453 mod 90) is 3 and the binary number 3 is "101", a non-STR virtual NAV can be set on links #1 and #3, and a non-STR virtual NAV can be left unset on link #4. When sending an aggregated (A)-MPDU, information about links with non-STR relationships can be sent. An A-MPDU can include multiple MPDUs, and the MAC header of each of the multiple MPDUs can include information about links with non-STR relationships as described above.

[0138] Frames containing information indicating the setting of the aforementioned non-STR virtual NAV can be sent. When a frame containing information indicating the setting of a non-STR virtual NAV is received, the communication node (e.g., AP MLD or STA MLD) can identify the link, duration, and the STA of the target STA MLD that has set the non-STR virtual NAV associated with the frame, and can immediately set the non-STR virtual NAV for the STA of the STA MLD on the corresponding link. In other words, since the setting information of the non-STR virtual NAV is included in the frame header, the non-STR virtual NAV can be set on another link based on the decoding result of the header. In this case, when the APMLD or STA MLD is sending a frame to a communication node that has set the non-STR virtual NAV, the transmission operation of the corresponding frame can be stopped.

[0139] On the other hand, it can be implemented according to the following scheme (e.g., Figures 10 to 12 The following implementation scheme is used to update parameters. In the following implementation scheme, CS can refer to the change sequence, CC can refer to the change counter, and CUF can refer to the critical update flag.

[0140] Figure 10 This is a timing diagram illustrating a third embodiment of a method for updating parameters in a multi-link wireless local area network system.

[0141] like Figure 10 As shown, information indicating whether parameters used for the first link have changed (e.g., a key update flag) can be sent / received in the second link. Furthermore, parameters changed for the first link can be sent and received in the first link. AP MLD1 and STA MLD1 can utilize two links (e.g., the first link and the second link). When parameters used for the first link have changed, AP1 of AP MLD1 can increment a change sequence (e.g., a change counter) by 1 and send a beacon frame including the incremented change sequence. After the parameters change, AP2 of AP MLD1 can send a beacon frame in the second link, the beacon frame including a key update flag indicating that the parameters have changed (e.g., a key update flag set to 1). STA2 of STA MLD1 can receive the beacon frame in the second link. When the key update flag included in the beacon frame is set to 1, STA2 of STA MLD1 can determine that the parameters (e.g., parameters used for the first link) have changed.

[0142] When a critical update flag is identified, STA1 of STA MLD1 may not receive frames containing changed parameters (e.g., beacon frames) in the first link. In this case, STA1 of STA MLD1 can send a probe request frame in the first link to receive the changed parameters. The probe request frame may include information requesting the transmission of the changed parameters and / or the change sequence stored in STA1. AP1 of AP MLD1 can receive the probe request frame from STA MLD1 in the first link. Upon receiving the probe request frame, AP1 of AP MLD1 can determine that the changed parameters are requested to be transmitted. Therefore, AP1 of AP MLD1 can send a probe response frame containing the changed parameters in the first link. For example, if the change sequence of STA1 included in the probe request frame is different from the current change sequence (e.g., the change sequence related to the updated parameters), AP1 of AP MLD1 can send a probe response frame containing the changed parameters to STA MLD1. STA1 of STA MLD1 can receive the probe response frame from AP1 of AP MLD1 in the first link and can update the parameters based on the information included in the probe response frame.

[0143] STA MLD1 can simultaneously perform a channel access procedure in both the first and second links to send probe request frames, and the channel access procedure can succeed in the second link before the first link. In this case, STA2 of STA MLD1 can send a probe request frame requesting the transmission of changed parameters to AP1 of AP MLD1 in the second link. The probe request frame transmitted in the second link may include information requesting the transmission of parameters for the first link (e.g., link identifier). AP2 of AP MLD1 can receive probe request frames from STA2 of STA MLD1 in the second link. AP2 of AP MLD1 can identify the requested transmission of parameters for the first link based on information included in the probe request frame (e.g., link identifier, AP identifier, or BSS identifier). In this case, AP MLD1 (e.g., AP1 and / or AP2) can send a frame including the changed parameters to STA MLD1.

[0144] On the other hand, after sending and receiving the aforementioned probe request / response frames, STA1 of STA MLD1 can receive beacon information in the first link and compare the changed sequence included in the received beacon information with a previous changed sequence (e.g., a changed sequence stored in STA1). When the changed sequence included in the received beacon information is different from the previous changed sequence, STA1 of STA MLD1 can determine that the parameters have changed and can perform a parameter update operation. This operation can be performed when no changed parameters are obtained from the probe response frame. A separate information request frame can be used instead of the aforementioned probe request frame, and a separate information response frame can be used instead of the aforementioned probe response frame.

[0145] Figure 11 This is a timing diagram illustrating a fourth embodiment of a method for updating parameters in a multi-link wireless local area network system.

[0146] like Figure 11 As shown, information indicating whether parameters used for the first link have changed (e.g., a key update flag) can be sent / received in the second link. Furthermore, parameters changed for the first link can be sent / received in the first link. AP2 of AP MLD1 can send a beacon frame including the key update flag in the second link. STA2 of STA MLD1 can receive beacon frames in the second link and can identify the key update flag included in the beacon frame. When the key update flag indicates that parameters used for the first link have changed (e.g., when the key update flag is set to 1), STAMLD1 can perform the operation of receiving frames including the changed parameters (e.g., beacon frames or probe response frames) in the first link for parameter updates.

[0147] STA MLD1, which does not support STR operations, can transmit data frames using the second link while receiving updated beacon frames (e.g., beacon frames with changed parameters). STA MLD1 cannot perform receive operations on the first link while transmitting data frames on the second link. Therefore, STA MLD1 may not receive beacon frames on the first link. The period during which receive operations are not performed on the first link can be a dead zone.

[0148] STA MLD1 can perform channel access operations in the first link (or the second link) to send a probe request frame after completing data frame transmission in the second link. When the channel is idle, STA MLD1 can send a probe request frame in the first link requesting the transmission of changed parameters. AP MLD1 can receive the probe request frame in the first link and determine the parameters for which the transmission change was requested. AP MLD1 can send a probe response frame in the first link including the changed parameters. STA MLD1 can receive the probe response frame in the first link and update the parameters based on the information included in the probe response frame. If the parameters are not updated by the probe request / response information, STA MLD1 can update the parameters by receiving a beacon frame in the next beacon transmission period of the first link.

[0149] Figure 12 This is a timing diagram illustrating a fifth embodiment of a method for updating parameters in a multi-link wireless local area network system.

[0150] like Figure 12 As shown, information indicating whether parameters used for the first link have changed (e.g., a key update flag) can be sent / received in the second link. Furthermore, parameters changed for the first link can be sent / received in the first link. AP2 of AP MLD1 can send a beacon frame including the key update flag in the second link. STA2 of STA MLD1 can receive beacon frames in the second link and can identify the key update flag included in the beacon frame. When the key update flag indicates that parameters used for the first link have changed (e.g., when the key update flag is set to 1), STAMLD1 can perform the operation of receiving frames including the changed parameters (e.g., beacon frames or probe response frames) in the first link for parameter updates.

[0151] STA MLD1 can be a non-STR STA MLD that does not support STR operations, and data frames for STA MLD1 can be generated when receiving an update beacon frame (e.g., a beacon frame including changed parameters). In this case, STA2 of STA MLD1 can perform a channel access operation in the second link to send data frames, and when the channel access operation is complete, the transmission of data frames can be delayed to receive update beacon frames in the first link.

[0152] STA1 of STA MLD1 can receive update beacon frames in the first link and update its parameters based on the information included in the update beacon frames. After receiving the update beacon frames, STA2 of STA MLD1 can transmit data frames in the second link after completing the channel access operation.

[0153] If the channel is idle within the "channel listening period + AIFS", the channel access operation can be considered successful. When the channel is busy, if the channel is idle within the AIFS starting from the end of the busy period, the communication node can perform a backoff operation. If the backoff operation is successful, the communication node can determine that the channel access operation was successful.

[0154] Embodiments of the present invention can be implemented as program instructions that are computer-executable and recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, or combinations thereof. The program instructions recorded on the computer-readable medium may be specifically designed and configured for the present invention, or may be known and available to those skilled in the art of computer software.

[0155] Examples of computer-readable media may include hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, and flash memory. Examples of program instructions include machine code produced by, for example, a compiler, and high-level language code executable by a computer using an interpreter. The aforementioned hardware devices may be configured to operate as at least one software module to perform embodiments of the present invention, and vice versa.

[0156] Although embodiments of the invention and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope of the invention.

Claims

1. A method for operating an access point multilink device in a wireless local area network, the method comprising: A first beacon frame is transmitted on the first link of a multi-link system. The first beacon frame includes at least one updated parameter for communication operations in the first link. On the second link of the multi-link system, a second beacon frame is sent to a non-access point multi-link device. The second beacon frame includes at least one piece of information indicating that at least one parameter has been updated or at least one piece of information including a count value for at least one parameter. Send a probe response frame, including at least one parameter, to a non-access point multilink device.

2. The method according to claim 1, further comprising: Receive probe request frames from non-access point multilink devices.

3. The method according to claim 1, wherein, The access point multi-link device includes a first access point and a second access point associated with the access point multi-link device. The first access point operates on the first link. The second access point operates on the second link. The non-access point multi-link device includes a first station and a second station associated with the non-access point multi-link device. The first station operates on the first link. The second station operates on the second link.

4. The method according to claim 1, wherein, The first beacon frame is sent to multiple devices, including non-access point multilink devices, using a broadcast method.

5. The method according to claim 1, wherein, The probe response frame is sent to multiple devices, including non-access point multi-link devices, using either broadcast or unicast methods.

6. The method according to claim 1, wherein, When a non-access point multilink device does not support simultaneous transmission and reception operations in multiple links and transmits a frame in a second link during the reception period of the first beacon frame in the first link, the first beacon frame is not received in the non-access point multilink device.

7. The method according to claim 1, wherein, The first and second beacon frames are periodically sent, and a third frame is sent upon request from a periodic or non-access point multilink device or another device.

8. The method according to claim 1, wherein, In order to receive probe response frames in a non-access point multilink device, transmission is prohibited during the period when the third frame is transmitted on links other than the link that transmitted the third frame.

9. A method for operating a non-access point multilink device in a wireless local area network, the method comprising: A beacon frame is received from an access point multilink device on the second link of the multilink, the beacon frame including first information indicating that at least one parameter for communication operation in the first link of the multilink has been updated or at least one of second information including a count value for at least one parameter. Based on the first and second information, at least one parameter is identified as being updated; Receive a probe response frame containing at least one parameter from the access point multilink device.

10. The method of claim 9, further comprising: Send a probe request frame to the access point multilink device.

11. The method according to claim 9, wherein, The access point multi-link device includes a first access point and a second access point associated with the access point multi-link device. The first access point operates on the first link. The second access point operates on the second link. The non-access point multi-link device includes a first station and a second station associated with the non-access point multi-link device. The first station operates on the first link. The second station operates on the second link.

12. The method according to claim 9, wherein, The first beacon frame is sent periodically, and the second beacon frame is sent according to requests from periodic or non-access point multilink devices or other devices.

13. The method according to claim 9, wherein, To ensure reception of the second beacon frame in a non-access point multilink device, transmission is prohibited during the period when the second beacon frame is being transmitted on links other than the link that is transmitting the second beacon frame.

14. The method of claim 9, further comprising: Perform channel access operations to probe the transmission of request frames; If the channel access operation is completed, the transmission of the probe request frame is delayed in order to receive the second beacon frame.

15. An access point multi-link device in a wireless local area network, the access point multi-link device comprising: At least one transceiver; At least one processor; as well as At least one computer memory operatively connected to at least one processor and storing instructions that, based on execution by the at least one processor, perform operations including: A first beacon frame is transmitted on the first link of a multi-link system. The first beacon frame includes at least one updated parameter for communication operations in the first link. On the second link of the multi-link system, a second beacon frame is sent to a non-access point multi-link device. The second beacon frame includes at least one piece of information indicating that at least one parameter has been updated or at least one piece of information including a count value for at least one parameter. Send a probe response frame, including at least one parameter, to a non-access point multilink device.

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