Wireless communication device and wireless communication method

Abstract

To provide a wireless communication device and a wireless communication method that can suppress the influence of interference between links in multi-link communication.SOLUTION: A wireless communication device according to an embodiment is connected to another wireless communication device via first and second links that have restrictions on use, transmits a first frame notifying the other wireless communication device of frequencies of the first and second links and notifying the same that one of the first and second links is set as a primary link, and executes at least one of first, second, third, and fourth operations. The first operation receives a second frame from the other wireless communication device over the primary link. The second operation transmits a third frame to the other wireless communication device over the primary link. The third operation receives a fourth frame from the other wireless communication device over the primary link and a secondary link simultaneously. The fourth operation transmits a fifth frame to the other wireless communication device over the primary link and the secondary link simultaneously.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] Embodiments of the present invention relate to a wireless communication device and a wireless communication method for performing multi-link communication.

Background Art

[0002] Multi-link communication in which wireless communication devices communicate via a plurality of wireless links is known. When transmitting and receiving independently over each of the plurality of wireless links, the bandwidth expands and the throughput improves. However, due to interference between wireless links, etc., it may not be possible to transmit and receive independently over each of the plurality of wireless links.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a wireless communication device and a wireless communication method capable of suppressing the influence of interference between links in multi-link communication.

Means for Solving the Problems

[0005] The wireless communication device according to the embodiment is connected to another wireless communication device via first and second links, transmits a first frame that notifies the frequencies of the first and second links and that one of the first and second links is set as the primary link, and performs at least one of the first, second, third, and fourth operations. There are constraints on the use of the first and second links. The first operation is to receive a second frame from the other wireless communication device on the primary link. The second operation is to transmit a third frame to the other wireless communication device on the primary link. The third operation is to receive a fourth frame from the other wireless communication device simultaneously on the primary and secondary links. The fourth operation is to transmit a fifth frame to the other wireless communication device simultaneously on the primary and secondary links. The secondary link is the other link between the first and second links. The radio communication device does not transmit the first frame on the secondary link, but transmits it on the primary link. [Brief explanation of the drawing]

[0006] [Figure 1] This figure shows an example of a wireless link used in multilink communication. [Figure 2] This figure shows an example of a wireless communication device that performs multilink communication. [Figure 3] This figure shows an example of a beacon frame format. [Figure 4] This figure shows an example of the format of the Reduced Neighbor Report element included in the frame body of a beacon frame. [Figure 5] This figure shows an example of the format of the Reduced Neighbor Report element in the first example of notifying information for multilink communication. [Figure 6] This figure shows an example of the format of a Reduced Neighbor Report element in a second example of notifying information for multilink communication. [Figure 7] This figure shows an example of the format of a Reduced Neighbor Report element in a third example of notifying information for multilink communication. [Figure 8]This table shows the relationship between the value of the TBTT Information Length subfield and the types of subfields included in the TBTT Information subfield. [Figure 9] This figure shows an example of the format of the Reduced Neighbor Report element in the fourth example of notifying information for multilink communication. [Figure 10] This diagram shows an example of three wireless links where Link2 and Link3 are in a non-STR link relationship, and Link1 and the other two wireless links are in an STR link relationship. [Figure 11] This figure shows an example of the format of ML elements included in the frame body of an association request frame. [Figure 12] This figure shows another example of the three wireless link states, where Link2 is in a non-STR link relationship with Link3, and also with Link1. [Figure 13] This figure shows another example of the ML element format. [Figure 14] This figure shows yet another example of the ML element format. [Figure 15] This figure shows yet another example of the ML element format. [Figure 16] This figure shows yet another example of the ML element format. [Figure 17] This figure shows some examples of relationships between wireless links that are non-STR and relationships between wireless links that are STR. [Figure 18] This figure shows several examples of relationships between wireless links that are non-STR and relationships between wireless links that are STR. [Figure 19] This figure shows yet another example of the ML element format. [Figure 20] This is a diagram showing an example of a wireless link. [Figure 21]This is a diagram showing an example of an AP MLD transmitting to a STA MLD. [Figure 22] This is a diagram showing an example of the format of a data frame. [Figure 23] This is a diagram showing an example of the format of an RTS frame. [Figure 24] This is a diagram showing an example of padding by frame aggregation. [Figure 25] This is a diagram showing an example of the format of a trigger frame. [Figure 26] This is a diagram showing an example of the format of an ML element in the second embodiment. [Figure 27] This is a diagram showing an example of a channel in the wireless LAN standard. [Figure 28] This is a diagram showing an example of a Status Code in the wireless LAN standard. [Figure 29] This is a diagram showing an example of a Status Code in the third embodiment. [Figure 30] This is a diagram showing an example of a table created by an AP MLD according to the fourth embodiment. [Figure 31] This is a diagram showing another example of a table created by an AP MLD according to the fourth embodiment. [Figure 32] This is a diagram showing yet another example of a table created by an AP MLD according to the fourth embodiment. [Figure 33] This is a flowchart showing an example of the classification process of a STA MLD by an AP MLD in the fourth embodiment. [Figure 34] This is a diagram showing an example of a Status Code in the sixth embodiment. [Figure 35] This is a diagram showing an example of the format of a MU EDCA parameter set element according to the seventh embodiment. [Figure 36] This is a diagram showing an example of a Status Code in the ninth embodiment. [Figure 37] This is a diagram showing an example of a Status Code in the tenth embodiment. [Figure 38] This figure shows an example of a trigger type subfield in the 11th embodiment. [Figure 39] This figure shows a first implementation example of the antenna in the 15th embodiment. [Figure 40] This figure shows a second implementation example of the antenna in the 15th embodiment. [Figure 41] This figure shows a third implementation example of the antenna in the 15th embodiment. [Figure 42] This figure shows a fourth implementation example of the antenna in the 15th embodiment. [Modes for carrying out the invention]

[0007] The embodiments will be described below with reference to the drawings. The following description exemplifies devices and methods for realizing the technical concept of the embodiments, and the technical concept of the embodiments is not limited to the structure, shape, arrangement, material, etc. of the components described below. Modifications that a person skilled in the art can easily conceive of are naturally included within the scope of disclosure. In order to make the explanation clearer, the size, thickness, planar dimensions, or shape of each element may be schematically represented in the drawings with modifications from the actual embodiments. Multiple drawings may include elements with different dimensional relationships or ratios. In multiple drawings, the same reference numeral may be used for corresponding elements to omit redundant explanations. Some elements may be given multiple names, but these examples of names are merely illustrative and do not preclude the use of other names for these elements. Similarly, elements that do not have multiple names may also be given other names. In the following description, "connection" means not only direct connection but also connection via other elements.

[0008] This embodiment will be described in detail below with reference to the drawings.

[0009] (First embodiment) Multilink communication In multilink communication, communication takes place between wireless communication devices using multiple wireless links. Multilink communication is also called multi-link operation (MLO).

[0010] A wireless link corresponds to frequency channels in different frequency bands or within the same frequency band. In IEEE 802.11-compliant wireless LANs using the 2.4GHz, 5GHz, and 6GHz bands, frequency channels are determined using channel bonding technology based on a 20MHz channel. That is, wireless LAN channels include 40MHz channels using two adjacent 20MHz channels, 80MHz channels using four adjacent 20MHz channels, 160MHz channels using eight adjacent 20MHz channels, or 80+80MHz channels using two sets of four adjacent 20MHz channels. These channels correspond to the frequency channels of a wireless link. Furthermore, especially in the 6GHz band, 320MHz channels, 160+160MHz channels, 240MHz channels, and 160+80MHz channels are also envisioned as wireless LAN channels.

[0011] In other words, a wireless link is the frequency channel used in a Basic Service Set (BSS), which is the unit of a wireless LAN system composed of an access point (AP) with a single Medium Access Control (MAC) address. The frequency channel used in the BSS is notified to wireless communication devices by the AP using beacon frames and probe response frames.

[0012] Figure 1 shows an example of a wireless link used in multilink communication. Three wireless links, Link 1, Link 2, and Link 3, are used, operating in three different frequency bands. For example, Link 1 operates in the 2.4 GHz band with a channel width of 20 MHz. Link 2 operates in the 5 GHz band with a channel width of 80 MHz. Link 3 operates in the 6 GHz band with a channel width of 160 MHz.

[0013] Naturally, the number of wireless links used in a multilink system is not limited to three; it could be two, four, or more. Multiple wireless links do not necessarily have to be in different frequency bands; they may be in the same frequency band. For example, two wireless links on 160MHz channels may be in the 6GHz band. The frequency bands are not limited to 2.4GHz, 5GHz, and 6GHz; as the number of available frequency bands for the wireless system increases, these may naturally be included as well.

[0014] For the 2.4GHz band, channels 1, 6, and 11 are usable without significant interference. Since channel numbers are assigned at 5MHz intervals, these three channels are spaced 25MHz apart. Therefore, although the IEEE 802.11 standard allows the use of 40MHz channels, channel bonding is not appropriate. Consequently, it is expected that a single 20MHz channel will be frequently selected for use in the 2.4GHz band.

[0015] 《AP MLD, STA MLD》 Generally, in multilink communication, the wireless communication device that acts as an AP on each wireless link is called an AP Multi-link Device (hereinafter referred to as AP MLD), and the wireless communication device that operates as a non-AP (terminal (STA)) on each wireless link is called a non-AP MLD. In wireless LANs compliant with the IEEE 802.11 standard, since an AP is a type of STA, an STA that is not an AP is expressed as a non-AP. However, a non-AP MLD can also be intuitively expressed as an STA as the terminal that communicates with an AP, so in this specification, for convenience, non-APs are referred to as STAs and non-AP MLDs are referred to as STA MLDs.

[0016] Wireless communication equipment Figure 2 shows an example of a wireless communication device that performs multilink communication.

[0017] AP MLD22 can perform multilink communication with STA MLD24A and 24B using multiple wireless links, for example, Link1 and Link2. The number of STA MLD24A and 24B units is not limited to two; it can be three or more, or even just one. The number of wireless links used for multilink communication is not limited to two; it can be three or more. When performing multilink communication using two wireless links, it is not limited to Link1 and Link2; it can be Link1 and Link3, or Link2 and Link3, for example. The combination of wireless links between AP MLD22 and STA MLD24A may be the same as, or different from, the combination of wireless links between AP MLD22 and STA MLD24B.

[0018] The basic structure of multilink communication between AP MLD22 and STA MLD24A and 24B is generally the same. Although not shown in Figure 2, AP MLD22 may also be connected to a wired infrastructure network. Furthermore, the implementation of AP MLD22 and STA MLD24A and 24B will differ depending on whether the two wireless links are in a non-STR link relationship or an STR link relationship (details will be described later).

[0019] One way to implement multilink communication is to provide a processing unit that controls access to the wireless medium and a physical processing unit in the wireless communication device for each wireless link. AP MLD22 and STA MLD24A, 24B each include a first physical processing unit (PHY1) 32 and a first lower MAC processing unit (LowerMAC1) 36 for Link1, and a second physical processing unit (PHY2) 34 and a second lower MAC processing unit (LowerMAC2) 38 for Link2, and further include a higher MAC processing unit 40 and a management entity 44. The lower MAC processing units 36 and 38 correspond to the processing units that control access to the wireless medium. In both AP MLD22 and STA MLD24A, 24B, the lower MAC processing unit 36 ​​and physical processing unit 32 use Link1, and the lower MAC processing unit 38 and physical processing unit 34 use Link2. Note that the first physical processing unit 32 and the second physical processing unit 34 may be configured to share some processing.

[0020] When performing multilink communication using three or more wireless links, a number of physical processing units and lower-level MAC processing units are provided corresponding to the number of links.

[0021] In a wireless LAN compliant with the IEEE 802.11 standard, the Media Access Control (MAC) layer controls access to the wireless medium and the higher-level logical link control (Logical The system defines processes such as data transfer between the Link Control (hereinafter referred to as LLC) layer and data queuing in response to power saving operations. Lower MAC processing units 36 and 38 perform the former processes, while the upper MAC processing unit 40 performs the latter processes. Note that the division of functions between the upper MAC processing unit 40 and the lower MAC processing units 36 and 38 is not limited to this example and may be changed.

[0022] The upper MAC processing unit 40 handles the data received from the upper layer, along with the information necessary to convert it into a data frame, as a MAC Service Data Unit (hereinafter referred to as MSDU). Furthermore, the upper MAC processing unit 40 also handles the management entity 44 (the management entity corresponding to the MAC layer is MAC The information necessary to generate a management frame, as instructed by the Layer Management Entity (hereinafter referred to as MLME), is treated as a MAC Management Protocol Data Unit (hereinafter referred to as MMPDU).

[0023] When the lower MAC processing units 36 and 38 receive the MSDU and MMPDU from the upper MAC processing unit 40, they generate a MAC frame (MAC Protocol Data Unit; hereinafter referred to as MPDU). A MAC frame consists of a MAC header, a Frame Body, and a Frame Check Sequence (hereinafter referred to as FCS).

[0024] The MAC header includes a field that indicates the frame type. This field is further subdivided into a Type field and a Subtype field.

[0025] MAC frames can be broadly categorized into data frames, management frames, and control frames. The type is identified in the Type field, and more specific type identifications are found in the Subtype field.

[0026] The MAC header also includes a field containing a sequence number indicating the transmission order of the data frame or management frame. Preferably, the sequence number is assigned by the higher-level MAC processing unit 40. For data frames, if QoS functionality is supported, the sequence number assignment is divided by the Traffic Identifier (TID) and the destination. Similarly, for management frames, the sequence number assignment is divided by the destination. Therefore, multiple sequence number spaces are provided for assigning sequence numbers. Generally, sequence The number space is a modulo 4096 counter.

[0027] FCS includes a 32-bit CRC (cyclic redundancy code) for error detection.

[0028] As described later, in multilink communication, each lower MAC processing unit 36, 38 has a MAC address. Therefore, following the previous rules, the resolution of the destination would be each MAC address of the destination link, and a sequence number space would have to be set up for each. However, in order to flexibly switch the link on which frames are transmitted, it is desirable to use the same sequence number between links, that is, to share the sequence number space between links. Therefore, in multilink communication, it is desirable to set up a sequence number space for each destination wireless communication device. As a way to handle destination wireless communication devices with multiple wireless links as a whole, for example, one can assign a MAC address (also called an MLD MAC address) to the upper MAC processing unit 40 in Figure 2 and use that. In this way, even at the data source, when the upper layer passes data, it is sufficient to know the MAC address of the upper MAC processing unit 40, and the upper MAC processing unit 40 can distribute the data to the appropriate lower MAC processing units 36, 38 for transmission. Another method is to use one of the MAC addresses of multiple wireless links as a representative.

[0029] The lower MAC processing units 36 and 38 perform access control to the wireless medium, such as Carrier Sense Multiple Access with Collision Avoidance (hereinafter referred to as CSMA / CA), and then send MAC frames to the wireless medium via the physical processing units 32 and 34. The MAC frames are ultimately converted into PHY packets (PHY Protocol Data Units; hereinafter also referred to as PPDUs) by the physical processing units 32 and 34 and transmitted to the wireless medium via an antenna (not shown). The lower MAC processing units 36 and 38 each have different MAC addresses. When generating MAC frames, the lower MAC processing units 36 and 38 write the MAC address for each wireless link in the Transmitting Address (TA) field of the MAC header. When generating MAC frames, the lower MAC processing units 36 and 38 write the MAC address at the link level of the opposing wireless link in the Receiving Address (RA) field of the MAC header. In broadcast frames, the lower MAC processing units 36 and 38 include the broadcast address in the RA, and in multicast frames, they include the multicast address in the RA.

[0030] The control frame within the MAC frame is a frame deeply involved in the operation when accessing the wireless medium, and therefore it is desirable that it be generated by the lower MAC processing units 36 and 38. Note that the aforementioned sequence number is not assigned to the control frame.

[0031] Management frames within a MAC frame include Beacon frames, Probe Request frames, and Probe Response frames. This includes Response frames, Authentication frames, Association Request frames, Association Response frames, etc.

[0032] Beacon frames are periodically transmitted from APs to notify STAs of BSS operation information and the modulation and coding scheme (MCS) used. Beacon frames are also transmitted from APs within AP MLDs. When APs within AP MLDs transmit beacon frames, they also include information related to AP MLDs, as described below. When an STA within an STA MLD receives a beacon frame transmitted by an AP within an AP MLD, it shares the information within that beacon frame as part of the STA MLD.

[0033] A probe request frame is a request from an STA to an AP to send information similar to that of a beacon frame. Probe request frames are also sent from STAs within the STA MLD. The recipient may also be an AP within the AP MLD. A probe response frame is sent to the STA as a response by an AP that received a probe request frame. Probe response frames are also sent from APs within the AP MLD. The recipient may also be an STA within the STA MLD. Probe response frames notify information similar to that of a beacon frame. When an AP within the AP MLD sends a probe response frame, it also includes information related to the AP MLD, as described below. When an STA within the STA MLD receives a probe response frame sent by an AP within the AP MLD, the STA MLD shares the information within that probe response frame.

[0034] Authentication frames, association request frames, and association response frames are used in the procedure for APs and STAs to connect. Frames are exchanged between any AP in an AP MLD and an STA in an STA MLD using the same radio link, and can be applied to the entire connection between the AP MLD and the STA MLD. Authentication frames are used to authenticate the other party and are sent by both the AP and the STA. Association request frames are sent from the STA to the AP, requesting a connection from the AP. When an association request frame is sent from an STA in an STA MLD to an AP in an AP MLD, the assignment of the radio link to be used between the STA MLD and the AP MLD is also requested in the association request frame. Association response frames are sent from the AP to the STA, notifying the STA of acceptance or rejection of the association request.

[0035] A data frame is basically a frame that stores data passed from a higher layer. However, in wireless LANs compliant with the IEEE 802.11 standard, there are also data frames that are not generated from the MSDU and have no data, i.e., no Frame Body. In wireless LANs compliant with the IEEE 802.11 standard, a concrete example of a data frame is the QoS Null frame. Data frames are used for purposes confined to the MAC layer. In particular, since the sequence number of a QoS Null frame can be set to any value, the higher MAC processing unit 40 is not involved, and it may be generated confined to the lower MAC processing units 36 and 38.

[0036] The management entity 44 corresponds to the Service Management Entity (hereinafter referred to as SME) in the IEEE 802.11 standard. It is further divided into the MLME for the MAC layer and the PHY Layer Management Entity (hereinafter referred to as PLME) for the PHY layer. Although not strictly represented in Figure 2, the MLME exchanges information with the higher-level MAC processing unit 40, and the PLME exchanges information with the physical processing units 32 and 34.

[0037] Each physical processing unit 32 and 34 passes the payload of the PHY packet received on each wireless link of the multilink communication, along with the MCS information used for reception and decoding, to the lower MAC processing units 36 and 38. The lower MAC processing units 36 and 38 extract the MAC frame from the payload. Each physical processing unit 32 and 34 also passes the reception level and reception timing information for signals that could not be decoded to the lower MAC processing units 36 and 38. The lower MAC processing units 36 and 38 use this information to perform carrier sensing.

[0038] The lower MAC processing units 36 and 38 extract the MAC frame. If the FCS determines that there are no errors, the lower MAC processing units 36 and 38 determine whether the MAC frame is addressed to their own terminal by checking the RA field in the MAC header. If the MAC address of the wireless link is listed in the RA field, the lower MAC processing units 36 and 38 extract the Frame Body from the MAC frame and determine whether it is necessary to send a response frame using the information in the MAC header. If it is necessary to send a response frame, the lower MAC processing units 36 and 38 generate an appropriate response frame and send it via the physical processing units 32 and 34. If the RA field is a broadcast address, the Frame Body is extracted from the MAC frame if it is a frame within the same BSS. Whether it is a frame within the same BSS is confirmed by the address field which contains the BSS Identifier (hereinafter referred to as BSSID), which is the MAC address of the AP. In MAC frames sent from the AP, the TA represents the BSSID. If the RA field is a multicast address, and the frame is within the same BSS and its multicast address includes the MAC address of the wireless link, then the Frame Body is extracted from that MAC frame. Broadcast addresses and multicast addresses are collectively called group addresses. When treating group addresses as MLDs, the MAC address of the AP MLD may be used instead of the BSSID.

[0039] The response frame is a control frame and includes Ack frames and Block Ack frames. Control frames always contain an RA, but do not necessarily contain a TA. In the case of a response frame, if the RA field is the MAC address of the wireless link, the lower MAC processing units 36 and 38 extract the Frame Body. Also, if the RA field in the response frame is a broadcast address, or if the RA field is a multicast address and includes the MAC address of the wireless link, and the MAC address to be received is listed in the TA, the lower MAC processing units 36 and 38 extract the Frame Body. The lower MAC processing units 36 and 38 pass the Frame Body, along with the sequence number extracted from the MAC header, the TA, the traffic identifier in the case of QoS data frames, and the final address of the data (Destination Address; hereinafter referred to as DA) in the case of AP MLD described later, if present, to the upper MAC processing unit 40.

[0040] The higher-level MAC processing unit 40 identifies the MAC address or representative MAC address of the higher-level MAC processing unit 40 of the source wireless communication device associated with the TA, and frames according to the traffic identifier. The Body is rearranged in sequence number order. In other words, the higher MAC processing unit 40 has a reordering buffer. In the case of a data frame, if the final destination is the local wireless communication device, the higher MAC processing unit 40 passes the Frame Body to the higher layer. When AP MLD22 receives a data frame and the DA is not the local wireless communication device, it performs forwarding. As a means of deriving the MAC address or representative MAC address of the higher MAC processing unit 40 of the wireless communication device that is sending the data from the TA, one method is to know in advance through negotiation between wireless communication devices which MAC address of which wireless link is used under which higher MAC processing unit 40 address or representative address. Another method is to notify each other of this information during the process of establishing communication on one of the wireless links. Furthermore, a rule may be set in advance for assigning some address to the MAC address or representative address of the higher MAC processing unit 40 and the MAC address of each wireless link, so that it can be determined from that rule.

[0041] In multilink communication between wireless communication devices, one wireless communication device acts as an AP (Access Point) on each wireless link. In a relationship where one device acts as an MLD and the other wireless communication device acts as an STA MLD on each wireless link, there is a method in which one of the multiple wireless links performing multilink communication is designated as the primary link, and at least one of the remaining wireless links are designated as secondary links. In the first embodiment, the AP MLD is assumed to set the primary link. Since links are related to frequency, the primary link is also called the primary frequency, and the secondary link is also called the secondary frequency.

[0042] In this system, the STA MLD checks the status of the wireless medium on the primary link. If the primary link is free, it acquires access rights to the primary link. If the secondary link is also free at the same time, it acquires access rights to the secondary link and transmits on both the primary and secondary links simultaneously.

[0043] When an AP MLD transmits a signal to an STA MLD, it acquires access rights based on the primary link, similar to the STA MLD, and transmits the signal to the STA MLD on the primary link. If the STA MLD is communicating on the primary link, and the AP MLD transmits a signal to that STA MLD on the secondary link of that STA MLD, interference will occur between the primary and secondary links of that STA MLD.

[0044] Therefore, in this method, if interference occurs between links, AP MLD will STA It is stated that sending messages to the STA MLD via a secondary link in the MLD should not be done.

[0045] However, depending on the wireless communication device, interference between wireless links can be a problem in some cases and not in others. When interference between wireless links is not a problem, multilink communication between wireless communication devices can transmit independently on each link. Therefore, there is no need to perform multilink communication based on the primary link, such as checking the status of the wireless medium to acquire access rights and transmitting on the secondary link simultaneously with the primary link if the secondary link is also free.

[0046] In the above-described multilink communication method based on the primary link, if transmission is possible on the secondary link but not on the primary link, the system is controlled to prevent transmission on the secondary link, thus reducing the transmission opportunities for the wireless communication device.

[0047] Furthermore, AP MLD can only send data frames to STA MLD if it is sent only on the primary link, or if both the primary and secondary links are available at the same time. However, if STA MLD is not performing a transmission, the transmission will only be made on the secondary link. Sending dataframes to MLD is technically feasible.

[0048] However, the above method does not consider a technique for transmitting data frames using only the secondary link. This would reduce the opportunities for AP MLD transmission.

[0049] Furthermore, in this scheme, if the STA MLD is transmitting data frames only on the primary link, the AP MLD should not transmit data frames to the STA MLD on the secondary link, taking into consideration interference between links.

[0050] However, in actual communication, even when the STA MLD sends a response frame on the receiving end of a data frame, the transmission to the STA MLD should not be performed over the secondary link at that time, but this measure has not been considered.

[0051] Therefore, this embodiment aims to enable AP MLDs to transmit without causing interference on wireless links where interference is a problem for each STA MLD. It also aims to enable sharing of wireless links in situations where STA MLDs that do not cause interference between wireless links are also present. Furthermore, this embodiment aims to prevent increased control complexity even when the primary links differ among the STA MLDs.

[0052] 《non-STR MLD, non-STR link》 Depending on the implementation method of wireless communication devices that perform multilink communication, limitations may arise between wireless links.

[0053] To actually transmit a signal from the physical processing units 32 and 34 to the wireless medium via the antenna, the signal must pass through an analog processing unit (not shown). The analog processing unit converts the digital PHY packet into an analog signal with a frequency corresponding to the wireless link and transmits it from the antenna. Upon reception, the analog processing unit converts the analog signal received by the antenna into a digital signal so that it can be processed by the physical processing units 32 and 34. It is conceivable that the RF filter used by this analog processing unit be shared across multiple physical processing units 32 and 34. The RF filter is a filter that allows only signals within the frequency range corresponding to the wireless link to pass through, and when shared across multiple physical processing units 32 and 34, the RF filter will have a frequency range wide enough to cover the frequencies of multiple wireless links that the multiple physical processing units 32 and 34 correspond to.

[0054] For example, if the analog processing unit of Link 2 and the analog processing unit of Link 3 in Figure 1 share an RF filter, when a signal is transmitted on Link 2, that transmitted signal leaks into Link 3, causing interference during reception on Link 3. In such a situation, even if Link 3 receives a PHY packet containing a frame with Link 3's MAC address as the RA (and thus destined for its own wireless communication device), it may not be able to receive and decode it correctly. For example, in wireless LANs compliant with IEEE 802.11, the minimum receiving sensitivity required by each MCS is specified, but even if the PHY packet is received with a receiving power exceeding that minimum receiving sensitivity, it may not be able to be decoded. In addition, there are situations where PHY packets cannot be decoded even if the adjacent channel rejection level is met. In other words, even if the requirements for receiving normal PHY packets are met, reception and decoding may not be possible.

[0055] Depending on the implementation method, it may be possible to decode PHY packets using low-level multi-level modulation such as Binary Phase Shift Keying (BPSK) by limiting the frequency range used for each wireless link with digital filters in the physical processing units 32 and 34, or by having a local oscillator (LO) for each wireless link.

[0056] However, if operating on only a single link, even under identical conditions of receive power and MCS (Multi-Card Score), where reception and decoding are possible without radio signal collisions, if one of two radio links is transmitting, the other may not be able to receive MAC frames addressed to its own radio communication device. Two radio links that cannot transmit and receive simultaneously on one side, i.e., two links that cannot transmit and receive simultaneously in parallel, are said to be in a non-simultaneous transmission and reception (hereinafter referred to as non-STR) link relationship.

[0057] Furthermore, a non-STR link can be defined as a radio link whose reception is restricted by transmission on another radio link, or a radio link that cannot transmit or receive independently of another radio link.

[0058] Depending on the implementation method, in two wireless links that are in a non-STR link relationship, carrier sensing may not be possible on the other link while one link is transmitting.

[0059] By separating the RF filter of the analog processing unit of Link 1 in Figure 1 from the RF filters of the analog processing units of Link 2 and Link 3, Link 1 can transmit and receive independently of Link 2 or Link 3, provided that Link 1's transmission and reception are not affected by the transmission and reception of Link 2 and Link 3. In this case, it is possible to receive and decode normally, satisfying the requirements for receiving normal PHY packets, and to perform standby operations that satisfy carrier sense specifications. In the following explanation, two wireless links that can transmit and receive simultaneously are referred to as being in a simultaneous transmission and reception (STR) link relationship.

[0060] Furthermore, an STR link can be defined as a wireless link whose reception is not restricted by transmission on another wireless link, or a wireless link that can transmit and receive independently of other wireless links.

[0061] If the relationship between two radio links is not STR, it is a non-STR relationship; if it is not non-STR, it is a STR relationship. It can also be said that whether or not two radio links are in a non-STR relationship depends on the frequency separation distance between the two radio links.

[0062] For example, in Figure 1, Link 2 and Link 3 may both be STR links if their frequencies are sufficiently far apart. Wireless communication devices that have the potential to produce non-STR links depending on how the wireless links are combined are called non-STR MLDs.

[0063] Furthermore, a non-STR MLD can communicate over one or more radio links, but when it is transmitting or receiving frames on one radio link, it cannot transmit or receive frames on other radio links. A non-STR MLD can (1) only transmit or receive data frames / management frames to or from other MLDs on one radio link at a time, and (2) can listen on one or more radio links. The listening operation is initiated by an initial control message (e.g., Request). The system includes receiving to Send (hereinafter referred to as RTS) / Multi-User RTS (hereinafter referred to as MU RTS) and Clear Channel Access (hereinafter referred to as CCA). The initial control message may include one or more of the following: spatial stream, MCS (data rate), PPDU type, frame type. Link switching delay is non-AP. MLD may be used as a guide.

[0064] On the other hand, a wireless communication device in which, regardless of the combination of wireless links, there is no possibility of two wireless links being in a non-STR link relationship, and any link can be used as an STR link, is called an STR MLD.

[0065] Furthermore, if, as a result of selecting the wireless links, all wireless links can be used as STR links, the wireless communication device is referred to as an STR MLD, and if at least two wireless links are in a non-STR link relationship, the wireless communication device may be referred to as a non-STR MLD. In the following description, unless otherwise specified, the definitions of STR MLD and non-STR MLD are those of the former. In this embodiment, the wireless communication device is a non-STR The main point of contention is not whether it's MLD or STR MLD, but whether the two wireless links are in an STR link relationship or a non-STR link relationship.

[0066] In this embodiment, AP MLD is an STR MLD in which two radio links are in an STR link relationship, regardless of the combination of radio links. On the other hand, STA MLD may be a non-STR MLD or an STR MLD. A wireless communication device that is both an STA MLD and a non-STR MLD is referred to as a non-STR STA MLD. A wireless communication device that is both an STA MLD and an STR MLD is referred to as an STR This is referred to as STA MLD. Even if non-STR STA MLD and STR STA MLD are mixed in a wireless communication system, both non-STR STA MLD and STR STA MLD can perform multilink communication with AP MLD.

[0067] 《Setting up the primary link for STA MLD via AP MLD and notifying STA MLD》 When the AP MLD22 transmits a beacon frame on each wireless link, it also notifies information about the communication status of other wireless links. For example, in a wireless LAN compliant with the IEEE 802.11 standard, information about the communication status of other AP MLDs can be notified using an information element called the Reduced Neighbor Report element. This embodiment also uses this element to notify the primary link.

[0068] Figure 3 shows an example of the format of a beacon frame transmitted by AP MLD22. More precisely, it is a beacon frame transmitted by AP MLD22 via one of the radio links. If transmitted from Link1, it is transmitted from the AP with the MAC address of the lower MAC processing unit 36; if transmitted from Link2, it is transmitted from the AP with the MAC address of the lower MAC processing unit 38. The beacon frame includes a MAC header, a Frame Body (variable length in octets), and an FCS (4 octets).

[0069] The MAC header includes a Frame Control field (2 octets), a Duration field (2 octets), an Address1 field (6 octets), an Address2 field (6 octets), an Address3 field (6 octets), a Sequence Control field (2 octets), and an HT Control field (0 or 4 octets).

[0070] The Frame Control field includes a Type subfield and a Subtype subfield. AP MLD sends a beacon frame, with the management frame's identification information in the Type subfield and the beacon's identification information in the Subtype subfield.

[0071] The Frame Body contains information specific to the frame type and frame subtype. The Frame Body contains numerous information elements.

[0072] Figure 4 shows an example of the format of a Reduced Neighbor Report element, which is an example of an information element included in the Frame Body of a beacon frame. The Reduced Neighbor Report element includes an Element ID field (1 octet), a Length field (1 octet), and a Neighbor AP Information field (variable length in octets).

[0073] The Neighbor AP Information field includes the Target Beacon Transmission Time (TBTT) Information Header subfield (2 octets), the Operating Class subfield (1 octet), the Channel Number subfield (1 octet), and the TBTT Information Set subfield (variable).

[0074] In wireless LANs compliant with the IEEE 802.11 standard, the center frequency position of the wireless link can be determined by the channel number. Channel numbers are assigned at 5MHz intervals. The AP MLD records this value in the Channel Number subfield. The AP MLD also records information including the channel width and the regulations (such as output restrictions) for each country and region in the Operating Class subfield.

[0075] These two subfields allow the STA MLD to determine at what frequency position and with what channel width the AP MLD is operating.

[0076] The TBTT Information Header field is a TBTT Information Field Type subfield (2 bits), Filtered It includes the Neighbor AP subfield (1 bit), the Reserved subfield (1 bit), the TBTT Information Count subfield (4 bits), and the TBTT Information Length subfield (8 bits). The Reserved field is currently unused and reserved for future use.

[0077] A TBTT Information Set subfield contains one or more TBTT Information subfields.

[0078] Each TBTT Information field includes a Neighbor AP TBTT Offset subfield (1 octet), a BSS Identifier (hereinafter referred to as BSSID) subfield (optional) (0 or 6 octets), a Short-SSID subfield (optional) (0 or 4 octets), and a BSS Parameters subfield (optional) (0 or 1 octet). The AP MLD enters the BSSID, which is the BSS identifier, in the BSSID subfield. The AP MLD enters the SSID, which is the service identifier of the wireless LAN system, in the Short-SSID subfield. The BSSID and Short-SSID subfields are not mandatory, and the Neighbor AP Information field does not need to include these subfields.

[0079] The BSS Parameters field consists of the OCT Recommended subfield (1 bit), Same SSID subfield (1 bit), Multiple BSSID subfield (1 bit), Transmitted BSSID subfield (1 bit), and Member Of ESS With 2.4 / 5 GHz. Co-Located AP subfield (1 bit), Unsolicited It includes a Probe Response Active subfield (1 bit), a Co-Located AP subfield (1 bit), and a Reserved subfield (1 bit).

[0080] The STA MLD can determine the frequency position and channel width used by surrounding APs (including the same device) by receiving a beacon frame containing the Reduced Neighbor Report element shown in Figure 4, but it cannot determine which APs are involved in multilink operation under the same AP MLD as the AP that sent the beacon frame.

[0081] The Reduced Neighbor Report element can include additional information fields. Therefore, the AP MLD according to this embodiment can notify the STA MLD of information by adding information to the information fields indicating whether the AP notified by the Reduced Neighbor Report element is used under the same AP MLD, and whether the radio link transmitting the beacon frame is the primary link.

[0082] Additionally, the AP MLD may assign a link identifier (hereinafter referred to as Link ID) to each wireless link and include the link identifier in this information field as well.

[0083] Figure 5 shows an example of the format of a Reduced Neighbor Report element with this information field added. Although not shown in Figure 5, TBTT The Information Header field contains subfields similar to those in Figure 4, and the TBTT Information Set field also contains subfields similar to those in Figure 4.

[0084] The Neighbor AP Information field, as in Figure 4, includes the TBTT Information Header subfield, the Operating Class subfield, the Channel Number subfield, and the TBTT Information Set subfield, and also includes the MLO subfield (1 octet).

[0085] The MLO subfield is an information field used to notify the STA MLD of information for multilink communication. It is added when the AP notified by the Reduced Neighbor Report element is used under the same AP MLD. The MLO field includes the Primary Link subfield (1 bit), the Link ID subfield (3 bits), and the Reserved subfield (4 bits).

[0086] The AP MLD includes information in the Primary Link subfield indicating whether the wireless link used by the AP notifying in the Reduced Neighbor Report element is the primary link. The AP MLD includes the link identifier of the wireless link used by the AP in the Link ID subfield. In order to notify that the wireless link used by the transmitted beacon frame is the primary link, information about the AP transmitting the beacon frame is also included in the Reduced Neighbor Report element. This should be included in the Neighbor Report element.

[0087] The Primary Link field only needs to be one bit in size. Set the Primary Link subfield to "1" if the wireless link used by the AP is the primary link, and to "0" if it is not the primary link. Limiting the maximum number of wireless links that the AP MLD can handle will limit the number of bits in the Link ID subfield. For example, if the maximum number of wireless links is limited to 8 and link identifiers are assigned starting from 0, the size of the Link ID subfield will be 3 bits. If the case where the link identifier is 0 is not used (reserved) to give it special meaning, then with 3 bits, the maximum number of links becomes 7. If the size of the MLO subfield is 1 octet as shown in Figure 5, and the Primary Link field is 1 bit and the Link ID field is 3 bits, the remaining 4 bits can be reserved for future use.

[0088] Next, we will describe second and third examples of methods for notifying information for multilink communication. In the first example, a new information field, such as the MLO field shown in Figure 5, is added to the Reduced Neighbor Report element. In the second and third examples, no new information field is added; instead, the Reserved bit in the existing Reduced Neighbor Report element is used to notify information for multilink communication.

[0089] As shown in Figure 4, the TBTT Information Header field in the Reduced Neighbor Report element includes the Reserved bit (B3). Figure 6 shows an example of the format of the Reduced Neighbor Report element in a second example that uses this bit B3 to notify information for multilink communication.

[0090] In the second example, the AP MLD includes Multi-Link (hereinafter referred to as ML) information in bit B3 of the TBTT Information Header field, which identifies whether the AP notified by the Reduced Neighbor Report element is performing multi-link operation under the same AP MLD. The AP MLD sets the ML bit to "1" if the AP is used under the same AP MLD, and to "0" if the AP is not performing multi-link operation under the same AP MLD.

[0091] When an STA MLD receives a beacon frame containing this ML bit, it reduces If the ML bit of the Neighbor Report element is "1", the radio link notified by that Reduced Neighbor Report element will be considered a candidate radio link to be used in multilink operation with the AP MLD that sent the beacon frame.

[0092] Furthermore, as shown in Figure 4, the BSS Parameters subfield within the TBTT Information field in the Reduced Neighbor Report element also includes the Reserved subfield (bit B7). Figure 7 shows an example of the format of the Reduced Neighbor Report element in a third example where this bit B7 is used to notify information for multilink communication.

[0093] The AP MLD records ML information similar to that in the second example in bit B7 of the BSS Parameters field. The method for setting the ML subfield in Figure 7 is the same as the ML subfield in Figure 6. Alternatively, while using the ML subfield in Figure 6, the last bit B7 of the BSS Parameters field may be used instead of Figure 7 to indicate whether it is the primary link or not. In this way, it is also possible to indicate which radio link will operate as the primary link. This bit B7 is the same as the Primary Link subfield in Figure 5.

[0094] Thus, in the examples of Figures 6 and 7, the AP MLD notifies the STA MLD via the ML bit whether the AP notified by the Reduced Neighbor Report element is operating in multilink mode under the same AP MLD. In the examples of Figures 6 and 7, a one-octet field similar to the MLO subfield in Figure 5 may be added to the end of the Reduced Neighbor Report element to notify whether the AP MLD has set the radio link from which it transmits beacon frames as the primary link. The MLO subfield in Figure 5, when present, indicates Reduced The Neighbor Report element notifies that the AP being notified is being used under the same AP MLD, thus replacing the ML subfield in Figures 6 and 7. On the other hand, if an MLO subfield is added in the examples of Figures 6 and 7, the ML field notifies whether the AP being notified by the Reduced Neighbor Report element is being used under the same AP MLD. This ML subfield exists when it is set to "1" and the AP being notified by the Reduced Neighbor Report element is operating in multilink mode under the same AP MLD. Thus, the combination of the MLO subfield and the ML subfield becomes a multi-stage notification method that additionally notifies primary link information and Link ID information.

[0095] Next, we will describe a fourth example in which AP MLD notifies STA MLD of information regarding the primary link.

[0096] The TBTT Information subfield within the Reduced Neighbor Report element is variable in size. The size of the TBTT Information subfield is determined by the value of the TBTT Information Length subfield. The type of subfields contained within the TBTT Information subfield is determined by the size of the TBTT Information subfield specified in the TBTT Information Length subfield.

[0097] Figure 8 is a table showing an example of the relationship between the value of the TBTT Information Length subfield in a wireless LAN standard and the types of subfields included in the TBTT Information subfield. For example, a value of 1 for the TBTT Information Length subfield indicates that the TBTT Information subfield includes only the Neighbor AP TBTT Offset subfield. A value of 2 for the TBTT Information Length subfield indicates that the TBTT Information subfield includes the Neighbor AP TBTT Offset subfield and the BSS parameters subfield. A value of 5 for the TBTT Information Length subfield indicates that the TBTT Information subfield includes the Neighbor AP TBTT Offset subfield and the Short-SSID subfield. Similarly, a value of 12 for the TBTT Information Length subfield indicates that the TBTT Information subfield includes the Neighbor AP TBTT Offset subfield, the BSSID subfield, the Short-SSID subfield, and the BSS parameters subfield.

[0098] The TBTT Information Length subfield currently has a value that is not in use (Reserved). A new subfield can be added to the TBTT Information field by defining the size of the new subfield included in the TBTT Information field so that the value of the TBTT Information Length subfield becomes one of these Reserved values. The AP MLD may use this subfield to notify whether the AP notified in the Reduced Neighbor Report element is used under the same AP MLD, and whether the wireless link of that AP is the primary link.

[0099] Furthermore, the AP MLD may include information in this subfield that identifies whether the AP is used under the same AP MLD, as well as the link identifier for the AP's wireless link in multilink operation, and may notify the link identifier of the wireless link set as the primary link using other information elements.

[0100] This link identifier may be, for example, the X written as LinkX in Figures 1 and 2. Figure 9 shows an example of the format of a Reduced Neighbor Report element in which a new ML Link ID subfield (1 octet) is defined after the BSS Parameters subfield in the TBTT Information field. The AP MLD enters the link identifier of the AP's wireless link to be notified in the Reduced Neighbor Report element in the ML Link ID subfield.

[0101] If the ML Link ID subfield is included in the TBTT Information field, then the BSSID subfield, Short-SSID subfield, and BSS Parameters subfield must also be included in the TBTT Information field. In this case, the value of the TBTT Information Length subfield should be set to 13.

[0102] If a rule is established that each wireless link used in multilink communication must have the same SSID, then the ML Link ID subfield will be the BSSID subfield and the BSS The TBTT Information field is always included in conjunction with the Parameters subfield. In this case, the value of the TBTT Information Length subfield should be set to 9.

[0103] One example of a wireless LAN standard is TBTT Information, as shown in Figure 8. The values ​​13 and 9 in the Length subfield are unused. If the values ​​13 or 9 are used for other purposes in the TBTT Information Length subfield, you can adjust the value in the ML Link ID subfield to satisfy one of the values ​​that remain Reserved.

[0104] Although the term "primary link" is used here, it may also be referred to as an "anchor link."

[0105] The AP MLD can use the ML Link ID subfield to notify the STA MLD of the wireless link set as the primary link, similar to the MLO subfield shown in Figure 5.

[0106] For example, AP MLD sets up three wireless links as shown in Figure 1 and uses a beacon frame transmitted via Link 1 to notify that Link 2 and Link 3 are available for multilink communication and that Link 2 is the primary link.

[0107] AP MLD notifies that Link1 and Link3 are available for multilink communication and that Link2 is the primary link using a beacon frame transmitted from Link2. In this case, since Link2 is the radio link being notified, if the Reduced Neighbor Report element does not include information about Link2 itself, it will not be possible to notify that Link2 is the primary link. In that case, AP MLD should notify that Link2 is the primary link using other information elements. Furthermore, AP MLD may also notify the identifier of the radio link being notified.

[0108] AP MLD notifies that Link1 and Link2 are available for multilink communication and that Link2 is the primary link using a beacon frame transmitted via Link3.

[0109] In the above explanation, it was stated that this information is notified to the STA MLD using information elements within the beacon frame, but it may also be notified to the STA MLD using information elements within the probe response frame. The probe response frame is a type of management frame that the AP MLD sends to the STA MLD in response to a probe request frame sent by the STA MLD, containing functional information, supported data rates, etc. The information elements related to the MLO can be added to this probe response frame, referring to the case of the beacon frame.

[0110] Alternatively, similar information may be communicated through other management frames, such as the Action frame. In this case, refer to the case of the Beacon frame and add the MLO-related information element to the Action frame.

[0111] In addition to the information mentioned above, notification may also be provided using the aforementioned information elements or new information elements. As mentioned earlier, the MAC address (6 octets) of the AP MLD is essential for sequence number processing in the STA MLD, so it needs to be included in some information element and notified to the STA MLD in a frame such as a beacon.

[0112] Notification of non-STR / STR link from STA MLD to AP MLD By the AP MLD notifying the STA MLD of the information described above, the STA MLD can determine which other radio links are available for multilink communication in the AP MLD simply by receiving the information from the AP MLD on any one radio link before connecting to the AP MLD on any radio link. Furthermore, before connecting to the AP MLD on any radio link, the STA MLD can determine which pairs of radio links that can communicate with the AP MLD via multilink are in a non-STR link relationship (or which radio links are non-STR links) in the STA MLD, or whether all pairs of radio links that can communicate with the AP MLD via multilink are in an STR link relationship (all radio links are STR links) in the STA MLD.

[0113] For example, similar to AP MLD, let's say we want STA MLD to perform multilink communication using Link1, Link2, and Link3. Figure 10 shows an example of three wireless links where Link2 and Link3 are in a non-STR link relationship, and Link1 and the other two wireless links, Link2 and Link3, are in an STR link relationship.

[0114] In the state shown in Figure 10, when the STA MLD establishes communication with the AP MLD, it notifies at least one AP within the AP MLD of the non-STR link relationship and the STR link relationship between the wireless links for which multilink communication is desired. In this case, the AP MLD may or may not notify the link identifier.

[0115] Since each BSSID, i.e., the MAC address of each AP within the AP MLD, is associated one-to-one with each wireless link, the STA MLD can use the MAC address of the AP within the BSSID / AP MLD as a substitute for the link identifier if the AP MLD has not notified it.

[0116] This section explains an example where the STA MLD notifies the AP MLD of the non-STR link relationship and the STR link relationship between wireless links, assuming the AP MLD has notified each link identifier.

[0117] Assume that the AP MLD has the MAC address AP1 for Link1, AP2 for Link2, and AP3 for Link3, and the STA MLD has the MAC address STA1 for Link1, STA2 for Link2, and STA3 for Link3.

[0118] First, let's assume that the STA MLD is connected to the AP MLD via Link1. In this case, the STA with MAC address STA1 receives beacon frames etc. containing the information elements shown in Figures 5 to 9 transmitted by the AP with MAC address AP1, and the AP The system understands that the MLD is performing multilink communication on Link 2 and Link 3 in addition to Link 1, and that Link 2 is the primary link. Furthermore, the STA with MAC address STA1 understands that the AP MLD uses the MAC address of AP2 on Link 2 and AP3 on Link 3. Based on this, the STA with MAC address STA1 sends an association request frame on Link 1 to the AP with MAC address AP1, attempting to establish a connection with the AP with MAC address AP1.

[0119] An association request frame is a type of management frame sent from an STA MLD to an AP MLD, and it includes information such as the data rates supported by the STA MLD and the SSID of the network to which the user wishes to connect.

[0120] The association request frame, like the beacon frame in Figure 3, includes a MAC header, Frame Body, and FCS. The Type subfield of the Control field contains the identification information of the management frame, and the Subtype subfield contains the identification information of the association request.

[0121] An STA with MAC address STA1 uses an information element in the Frame Body of the association request frame to notify the AP with MAC address AP1 of other link information available in the STA MLD. The STA with MAC address STA1 may also notify this information using an information element defined, for example, a Multi-Link (ML) element. The STA with MAC address STA1 may also notify this information by including it in other information elements added as extensions to the wireless LAN standard, such as the Extremely High Throughput (hereinafter referred to as EHT) Capabilities element.

[0122] This section explains the case where notification is made using an ML element, which is defined as one of the information elements within the Frame Body of an association request frame. However, the method of notification on the STA MLD side and the method of obtaining the information on the AP MLD side remain basically the same even if the type of information element changes. Therefore, even if an EHT Capabilities element is used instead of an ML element, the same processing as described below will be performed.

[0123] Furthermore, when an STA MLD transfers a connection from one AP MLD to another, if those AP MLDs constitute the same Extended Service Set (hereinafter referred to as ESS), the STA MLD can use the reassociation process with the destination AP MLD. An ESS is a set of interconnected BSSs that can be treated as a single BSS in the Logical Link Control (hereinafter referred to as LLC) layer within the data link layer of the OSI reference model.

[0124] The re-association request frame that STA MLD sends to AP MLD during the re-association process can also be used for notification in the same way as the association request frame described above. The re-association request frame is also a type of management frame. The basic structure of the re-association request frame is the same as the beacon frame shown in Figure 3. The difference between the re-association request frame and the beacon frame is the Subtype and the information elements included in the Frame Body. The Subtype of the re-association request frame is re-association request.

[0125] STA MLD notifies AP MLD in the ML element within the association request frame sent by STA1 that Link2 and Link3, configured by AP MLD, are available, and whether Link2 and Link3 are in a non-STR link relationship with other links. Note that if there is no non-STR link relationship, it is an STR link relationship, so whether there is a non-STR link relationship can also be interpreted as whether there is an STR link relationship.

[0126] In the example in Figure 10, STA MLD indicates that Link2 has an STR link relationship with Link1 and a non-STR link relationship with Link3, and that Link3 has an STR link relationship with Link1 and a non-STR link relationship with Link2, as indicated by AP. This LD will be notified.

[0127] The STA MLD selects all or a subset of the multiple radio links notified by the AP MLD and notifies the AP MLD of the selected radio links to be used. In this selection, the STA MLD selects radio links that are non-STR relative to the radio link designated as the primary link, but selects radio links in a way that avoids the relationship shown in Figure 18(b) described later. If it is possible to determine whether a link is non-STR or STR based on the difference in frequency separation between the links, the STA MLD determines that the two links are non-STR links if the difference in frequency separation between the links is within a threshold. If the STA MLD has an information management database for radio links that are in an STR relationship, the MAC processing layer may access this information management database, retrieve the information, and determine whether the two radio links are in an STR relationship.

[0128] Figure 11 shows an example of the format of ML elements included in the Frame Body of an association request frame. The STA MLD can use the ML elements shown in Figure 11 to notify the AP MLD of information regarding non-STR links and STR links.

[0129] The basic structure of an association request frame is the same as that of a beacon frame, as shown in Figure 3. The difference between an association request frame and a beacon frame lies in the subtype and the information elements included in the frame body. While the subtype of a beacon frame is beacon, the subtype of an association request frame is association request. The frame body of an association request frame can also contain numerous information elements. Figure 11 shows an example of the format of an ML element, which is an example of an information element included in the frame body of an association request frame.

[0130] The ML element consists of the Element ID field (1 octet), Length field (1 octet), Element ID Extension field (1 octet), STA MLD field (6 octets), Number Of Link Information Sets field (1 octet), and Link Includes an Information Set field (variable length in octets).

[0131] The ML element in Figure 11 differs from the Reduced Neighbor Report element in Figure 4 in that a new Element ID Extension field has been added after the Length field. This is because the number of Element IDs used to identify information elements in wireless LAN standards compliant with the 802.11 standard has reached the upper limit of what can be represented in one octet, making it impossible to define a new ML element as is. Only when the Element ID takes the maximum value of "255" is the Element ID Extension field added, allowing for the addition of a Subelement ID to identify the information element.

[0132] The Element ID Extension field also has one octet. In current 802.11 compliant wireless LAN standards, a value of "0" in this field means it is reserved, and a value of "1" or greater is assigned to identify the information element, similar to the Element ID. This is where the unique value for identifying the ML element is recorded.

[0133] In the ML element shown in Figure 11, the STA MLD field is placed after the Element ID Extension field. The STA MLD field is STA Notify the MAC address of the MLD.

[0134] The Number Of Link Information Sets field is placed after the STA MLD field. The Number Of Link Information Sets field indicates the number of Link Information subfields that make up the Link Information Set field.

[0135] The Link Information Set field is placed after the Number of Link Information Sets field. The Link Information Set field contains one or more Link Information subfields (3 octets).

[0136] The Link Information subfield consists of the Link ID subfield (1 octet), the Non-STR Link 1 subfield (1 octet), and the Non-STR Link 2 subfield (1 octet). The Link ID subfield indicates the link identifier of wireless links other than the wireless link that notifies the ML element. The Non-STR Link 1 subfield is Link The ID subfield notifies the link identifier of another first radio link that is a non-STR link to the radio link with the link identifier notified in the Link ID subfield. The Non-STR Link 2 subfield notifies the link identifier of another second radio link that is a non-STR link to the radio link with the link identifier notified in the Link ID subfield. Radio links other than those notified as non-STR links become STR links.

[0137] Assuming the wireless link status in AP MLD is as shown in Figure 10, STA The MLD (Multi-Level Database) records the link identifier for Link2 in the Link ID subfield of the first Link Information field. Since Link3 is the other first wireless link that has a non-STR link relationship with Link2, the STA MLD records the link identifier for Link3 in the Non-STR Link 1 subfield. The link identifiers for Link2 and Link3 are, for example, "2" and "3". Since Link3 is the only wireless link that has a non-STR link relationship with Link2, the STA MLD records information indicating Not Available (hereinafter referred to as N / A) in the non-STR Link 2 subfield. The information indicating N / A is, for example, "0". If numbers starting from 0 are assigned to the link identifiers of wireless links, then, for example, the maximum value of this subfield, "255", could be used as information to identify N / A.

[0138] STA MLD is the Link in the second Link Information field. The link identifier for Link3 is entered in the ID subfield. Since Link2 is the only other wireless link with which Link3 is a non-STR link, the STA MLD enters the link identifier for Link2 in the Non-STR Link 1 subfield and enters information indicating N / A in the non-STR Link 2 subfield.

[0139] Since the relationship between Link3 and Link2 as non-STR links has already been notified in the first Link Information field, STA MLD may omit this notification in the second Link Information field and instead enter N / A information in the Non-STR Link 1 subfield and Non-STR Link 2 subfield.

[0140] In this example, STA MLD first notified the non-STR / STR link relationship for Link2, then the non-STR / STR link relationship for Link3, and so on, in ascending order of link identifiers. However, since the Link Information field includes the Link ID subfield, STA MLD does not necessarily need to notify the links in ascending or descending order of link identifiers. However, adopting a rule of notifying in ascending or descending order of link identifiers is convenient for managing wireless link information in implementation.

[0141] Figure 12 shows another example of the three wireless links. Here, Link 2 is in a non-STR link relationship with Link 3, and Link 2 is also in a non-STR link relationship with Link 1.

[0142] If the wireless link status is as shown in Figure 12, the STA MLD will enter the link identifier for Link2 in the Link ID subfield of the first Link Information subfield of the ML element shown in Figure 11, enter the link identifier for Link1 in the Non-STR Link 1 subfield, and enter the link identifier for Link3 in the Non-STR Link 2 subfield.

[0143] The STA MLD sends an association request frame containing this ML element over Link1. The above notification method does not explicitly and directly notify whether Link1 and the other radio link are in a non-STR link relationship. However, if the STA MLD notifies the AP MLD whether Link1 and the other radio link are in a non-STR link relationship, the AP MLD can, based on the symmetry of that notification, automatically determine whether Link1 and the other radio link are in an STR link relationship or a non-STR link relationship.

[0144] Another way to notify that two radio links are in an STR link or non-STR link relationship is to include a field that indicates which other radio links the link transmitting the ML element (Link1 in the examples in Figures 10 and 12) is in an STR link or non-STR link relationship with. Figure 13 shows an example of the format of an ML element with this notification field added. The Link Information field contains multiple pairs of Link ID subfields (3 bits) and STR / Non-STR Flag subfields (1 bit). If the Link Information field is limited to, for example, one octet, then the Link Information field will contain a maximum of two sets of Link ID subfield (3 bits) and STR / Non-STR Flag subfield (1 bit) pairs.

[0145] This document explains how to indicate that the remaining fields contain no information when a Link Information field is generated that includes only one pair of Link ID subfields (3 bits) and STR / Non-STR Flag subfields (1 bit).

[0146] If the link identifier for a wireless link is set to a value of 1 or greater, with 0 designated as Reserved, setting the Link ID subfield to 0 allows the AP MLD to determine that the subfields after that subfield contain no information, and the AP MLD does not need to process the remaining subfields. The same applies if the range for assigning the link identifier for a wireless link is 0 to 6, with 7 designated as Reserved.

[0147] Alternatively, as shown in Figure 14, instead of using Figure 13, the Link Information field can be limited to one octet, and only one set of Link ID subfield (3 bits) and STR / non-STR Flag subfield (1 bit) can be included. While the Link ID subfield is 3 bits here, it can be made longer to adequately represent the identifiers for all necessary wireless links. The remaining area of ​​the octet becomes Reserve. Furthermore, if the last bit B7 is made into a More subfield indicating whether there is a subsequent Link Information field, the Number Of Link Information Sets field (1 octet) as in Figure 13 becomes unnecessary. With this 1-bit More subfield, the Reserved field becomes 3 bits, as shown in Figure 14.

[0148] STA MLD enters the link identifiers of radio links other than the radio link transmitting the ML element (in this case, Link1) (Link2 and Link3 in the examples in Figures 10 and 12) in the Link ID subfield. STA MLD enters flag information in the STR / Non-STR Flag subfield indicating whether the radio link transmitting the ML element and the radio link with the link identifier entered in the Link ID subfield are in an STR link relationship or a non-STR link relationship. STA MLD sets the flag information to "1" if Link1 and the radio link with the link identifier entered in the Link ID subfield are in an STR link relationship, and Link1 and Link If the wireless link of the link identifier listed in the ID subfield is a non-STR link, the flag information should be set to "0". The STR / Non-STR Flag subfield may also be called the STR Flag subfield. Alternatively, Link1 and Link If the wireless link of the link identifier listed in the ID subfield is in a non-STR relationship, the flag information may be set to "1". If the wireless link of Link1 and the link identifier listed in the Link ID subfield is in an STR link relationship, the flag information may be set to "0". In this case, the STR / Non-STR Flag subfield may be replaced with a Non-STR / STR Flag subfield or a Non-STR Flag subfield.

[0149] If there are other radio links that are not in a non-STR link relationship with Link1, STA MLD may notify the non-STR link relationship of those other radio links. In that case, the link identifier of the radio link to be compared must be explicitly specified. For example, as shown in Figure 15, instead of Figure 13, the Link Information field may consist of a Link ID1 subfield (3 bits), a Link ID2 subfield (3 bits), a STR / Non-STR Flag subfield (1 bit), and the remaining 1 bit set to Reserved, so that the Link Information field is 1 octet. The Link ID1 subfield contains the link identifier of the radio link to be compared, and the Link ID2 subfield contains the link identifier of the radio link to be compared. The usage of the STR / Non-STR Flag subfield is the same as in Figure 13, and the radio link listed in the Link ID2 subfield is Link The ID1 subfield indicates whether the wireless link has an STR (Structured Link) or non-STR (Structured Link) relationship.

[0150] Alternatively, as shown in Figure 16, instead of Figure 13, the Link Information field consists of a Link ID subfield (3 bits) and STR / Non-STR A Flag Bitmap subfield (5 bits) may also be used. The link identifier of the wireless link to be compared is placed in the Link ID subfield, and the link identifiers of other wireless links to be compared are omitted. The bits in the STR / Non-STR Flag Bitmap subfield indicate whether the wireless link to be compared has an STR relationship or a non-STR relationship with the wireless link to be compared, in order of Link ID. In the STR / Non-STR Flag Bitmap subfields B3-B7, B3 represents Link1, B4 represents Link2, and B5 represents Link3. For example, if Link1 is set in the Link ID subfield, then as shown in Figure 12, if Link2 has a non-STR relationship with Link1 and Link3 has an STR relationship with Link1, then B4 will contain "0" indicating a non-STR relationship and B5 will contain "1" indicating an STR relationship. Rules should be established such as putting "0" in the corresponding bit when the wireless link to be compared is the wireless link to be compared, and putting "0" in the bits assigned to identifiers of non-existent wireless links (in the above example, up to Link5 can be represented by this bitmap, but only up to Link3 is used). By setting the STR / Non-STR Flag Bitmap subfields to B3-B6 and leaving B7, it is possible to represent up to Link 4, and as mentioned above, assigning B7 to the More subfield eliminates the need for the Number of Link Information Sets field (1 octet) as shown in Figure 13.

[0151] The AP MLD only needs to know which wireless links the STA MLD can handle and which two of those wireless links are in a non-STR link relationship.

[0152] Thus, it is more efficient for the STA MLD to notify the relationship between wireless links when the AP MLD notifies the STA MLD of the link identifier in a beacon / probe response frame than when the AP MLD does not. If the MAC address is included in the field to represent the wireless link, 6 octets are required. However, if the AP MLD has previously notified the link identifier in a beacon / probe response frame, the length of the field representing the wireless link can be reduced to 1 octet or less when the STA MLD notifies the relationship between wireless links. As a result, the information elements used in notifications from the STA MLD, and consequently the frame length, can be shortened.

[0153] On the other hand, when representing a wireless link with a BSSID / MAC address, it is usually 6 octets, but if certain conditions are met, such as the AP MLD performing multilink communication, then it is possible to omit the value being represented, for example, by extracting and using a portion of the area, such as the last octet, in order to distinguish it from other APs within the AP MLD under multilink communication.

[0154] In the above explanation, it was assumed that the STA MLD can use all the same wireless links that the AP MLD can use, but it may not always be able to support all of them. In such cases, the STA MLD notifies the AP MLD of the wireless links it can support using an ML element. For example, if the STA MLD cannot support Link 3, it will not put the Link Information for Link 3 into the ML element, but will only put the Link Information for Link 2 into the ML element. In this case, if we consider the state after removing Link 3 based on Figure 10, there will be no wireless links that have a relationship with Link 2 as a non-STR link, so the STA MLD will enter N / A information in both the non-STR Link1 and Non-STR Link2 subfields of Link 2 according to the notification method in Figure 11.

[0155] Furthermore, aside from cases where it is simply unable to support a link, STA MLD may also use some algorithm to limit the number of wireless links it uses to a portion of those notified by AP MLD, even if it is capable of supporting all of them. This may be due to implementation reasons such as minimizing the number of wireless links managed by STA MLD, or QoS reasons such as avoiding the Dynamic Frequency Selection (DFS) band for stream data transmission.

[0156] In such cases, STA MLD will only include Link Information for the restricted (actually intended data exchange) wireless links in the ML element for the AP. You should notify MLD.

[0157] 《Constraints on non-STR link relationships》 In the ML element shown in Figure 11, the Link ID subfield is followed by two subfields: the Non-STR Link1 subfield and the Non-STR Link2 subfield. This limits the number of wireless links that have a non-STR relationship to one wireless link to two.

[0158] The role of the primary link Next, we will explain the relationships between non-STR wireless links and the primary link.

[0159] A primary link is the link used to gain access (channel access) among multiple wireless links that are in a non-STR link relationship. Even when there are multiple pairs of wireless links that are in a non-STR link relationship, one of them becomes the primary link, and the other wireless links become secondary links.

[0160] In this embodiment, the AP MLD determines the primary link. The STA MLD identifies multiple wireless links that the AP MLD has notified it of as available, and also identifies the primary link determined by the AP MLD. Based on the identified links, the STA MLD determines which wireless link it will use, notifies the AP MLD, and, once the AP MLD grants permission to connect, performs multilink communication with the AP MLD.

[0161] At that time, STA MLD takes into account the notification information from AP MLD and the non-STR / STR relationships between the candidate radio links that STA MLD itself will use and other radio links to determine which radio links it will use, and notifies AP MLD of the radio links to be used and the STR / non-STR relationships between them.

[0162] The STA MLD determines which radio links to use based on the conditions relating to the non-STR links. One of the constraints is to keep the number of radio links that are in a non-STR relationship with a given radio link within an upper limit. As mentioned above, based on the configuration of the ML element in Figure 11, the number of radio links that are in a non-STR relationship with a given radio link is limited to two. The STA MLD can see that if the received ML element is configured as shown in Figure 11, the number of radio links that are in a non-STR relationship with a given radio link is limited to two. This upper limit may be explicitly notified in advance by the AP MLD via a beacon frame or the like, or it may be specified in advance by the standard.

[0163] For STA MLD to transmit data frames or management frames over multilink communication, it must be able to obtain access rights on at least the primary link. For example, if STA MLD can obtain access rights on the primary link via CSMA / CA, STA MLD will transmit frames only on that primary link. Before configuring multilink communication, such as by sending an association request frame, STA MLD can access channels regardless of the primary link, but in that case, it is limited to any one wireless link. In the example above, an association request frame is being sent on Link 1.

[0164] If the STA MLD can acquire access rights on the secondary link simultaneously with the primary link, or if the STA MLD can tolerate a time difference in the start of transmission and transmit on the secondary link in accordance with the Transmission Opportunity (TXOP) on the primary link, the STA MLD may transmit on the secondary link as well. This restriction does not apply to independent radio links that are not in a non-STR link relationship.

[0165] Now, let's consider the transmission of STA MLD.

[0166] If STA MLD communication is limited to the primary link, fairness with STA MLDs communicating on other wireless links is not an issue.

[0167] On the other hand, if STA MLD can communicate on the secondary link based on the primary link, we can assume a scenario where it communicates simultaneously on both the primary and secondary links. In this case, if NAV (described later) or random backoff is used as the channel access method in CSMA / CA on the secondary link, the opportunities for STA MLD to communicate on the secondary link are likely to be few.

[0168] On the other hand, if PIFS access (described later) is allowed on the secondary link, as in the case of channel bonding, channel access in STA MLDs where any two radio links are in an STR link relationship will be disadvantageous, and it will also be unfair to Overlapping BSS (hereinafter referred to as OBSS) STAs.

[0169] Furthermore, in order for the AP MLD to be able to understand the communication status of the STA MLD, including other wireless links that are in a non-STR link relationship, once the AP MLD has confirmed the communication status on the primary link, the STA MLD should immediately release the access rights acquired on the secondary link if it fails to acquire access rights on the primary link, even if it acquires access rights on the secondary link, although a slight time lag may be allowed.

[0170] In this way, the AP MLD can determine whether the STA MLD is communicating (i.e., acting as a TXOP holder or TXOP responder) by observing the communication status of the primary link only before transmitting to the STA MLD. Therefore, it is possible to avoid the AP MLD's transmission interfering with the STA MLD's communication.

[0171] A TXOP holder is the party that has acquired transmission access rights, and a TXOP responder is the communication partner of the TXOP holder. The premise here is that the communication partner of an STA MLD is an AP MLD. In an infrastructure BSS centered around APs, there is also communication between STAs (Direct Link communication), but this will be discussed in a separate implementation.

[0172] Examples of non-STR / STR link relationships Figures 17 and 18 show some examples of two wireless links in a non-STR link relationship and two wireless links in an STR link relationship.

[0173] Figure 17(a) shows a slightly different relationship between the wireless links described above, where Link1 is the primary link, and in STA MLD, Link1 and Link2 are in a non-STR link relationship, while Link3 is in an STR link relationship with the other two wireless links, Link1 and Link2.

[0174] AP MLD sets one of the two wireless links with close frequency separation as the primary link. For example, if Link 3 is sufficiently far from both Link 1 and Link 2, AP MLD sets either Link 1 or Link 2 as the primary link. In the example in Figure 17(a), AP MLD sets the wireless link at one end (Link 1) when the three wireless links are arranged in frequency order as the primary link.

[0175] Figure 17(b) shows the case where the frequencies of the three radio links are relatively close together. In this case, AP MLD sets the middle radio link (Link2) as the primary link when the three radio links are arranged in frequency order. The middle Link2 is selected as the primary link because it is the link that is likely to have the most non-STR link relationships (2 non-STR link relationships).

[0176] In this case, with STA MLD, Link1 and Link2 are in a non-STR link relationship, and Link2 and Link3 are also in a non-STR link relationship. On the other hand, Link1 and Link3 have a long frequency separation distance and are in an STR link relationship.

[0177] However, even if there are three wireless links, and as shown in Figure 17(c), the central Link2 is in a non-STR link relationship with the left and right Link1 and Link3, and the left and right Link1 and Link3 are also in a non-STR link relationship, if the central one, Link2 in this figure, is set as the primary link, the STA MLD can transmit based on the primary link.

[0178] AP MLD can determine whether STA MLD is acting as a TXOP holder or TXOP responder simply by observing the communication status of the primary link.

[0179] The example in Figure 17 shows the case where there are three wireless links, but the same applies when there are four. For example, consider the case shown in Figure 18(a) where Link1 and Link2 are non-STR links, Link3 and Link4 are non-STR links, and all other links are STR links. In such a case, the non-STR link set 1 of Link1 and Link2 and the non-STR link set 2 of Link3 and Link4 can be treated independently. Therefore, if one of the two links constituting each link set is set as the primary link, the AP MLD can determine whether the STA MLD is a TXOP holder or TXOP responder simply by observing the communication status of the primary link.

[0180] The number of links that make up a link set does not have to be limited to two; it can be three or more. For example, as shown in Figures 17(a), (b), and (c), the same applies when three wireless links that are in a non-STR link relationship can each independently form a link set. The AP MLD only needs to set one of the three or more wireless links as the primary link within an independent link set. The AP MLD can pre-determine the wireless links that can form a wireless link set based on the separation distance between the frequencies of each wireless link, and then set the primary link for each set.

[0181] On the other hand, consider a configuration where two wireless links, Link2 and Link3, which are in a non-STR link relationship with each other, have further distinct non-STR links, such as Link1 and Link4, respectively. For example, assume that Link2 is set as the primary link, and the STA MLD attempts to use all four wireless links, Link1 to Link4, with the AP MLD.

[0182] In this case, Link4 has an STR link relationship with Link2, so according to the primary link rules mentioned above, Link4 should be able to transmit independently of Link2. However, Link4 has a non-STR link relationship with Link3, and Link3 has a non-STR link relationship with Link2, so it is affected by Link2 and Link3. Therefore, when an STA MLD attempts to transmit on Link4, it must check the communication status of Link2 in addition to Link3. Furthermore, if the STA MLD does not do this, the original simple verification operation, which would allow the AP MLD to avoid interference with the STA MLD's transmission by checking the communication status of the STA MLD (which has a non-STR link relationship) only on the primary link after setting the primary link, becomes impossible.

[0183] The same problem occurs when Link3 is set as the primary link.

[0184] Therefore, in the case of Figure 18(b), there is no benefit in setting a primary link. As shown in Figure 18(a), if non-STR link set 1 and non-STR link set 2 are far apart in frequency, one primary link can be set for each, but a primary link cannot be set for non-STR link set 1 and non-STR link set 2, which are mutually non-STR links.

[0185] To solve this problem simply, the STA MLD should select wireless links that have a relationship like those shown in Figures 17(a) and (b). For example, if Link 2 is set as the primary link, the STA MLD will avoid using either Link 1, Link 3, or Link 4. In this way, the STA MLD should select wireless links so that two links in a non-STR relationship (Link 2 and Link 3 in Figure 18(b)) do not further form non-STR relationships with other different links. In the above example, there can be a maximum of two other wireless links that are in a non-STR relationship with one wireless link.

[0186] Furthermore, in cases where a non-STR link relationship indirectly arises between a wireless link that is part of an STR link and the primary link, there is another solution: the access rights acquisition decision is made to establish a non-STR link relationship. In this case, it is not necessary to exclude the case shown in Figure 18(b).

[0187] The purpose of setting a primary link is to ensure that, when an AP MLD attempts to transmit on another wireless link, the communication status of an STA MLD that has a non-STR link relationship can be monitored by observing the communication status of the primary link, thereby guaranteeing whether the STA MLD is communicating on other wireless links. Therefore, if this guarantee can be achieved, the conditions for wireless links that have a non-STR link relationship may be relaxed.

[0188] For example, if the AP MLD can determine whether to transmit to the STA MLD by observing only the communication status of the primary link, the condition that there can be up to two non-STR link relationships can be relaxed, and the number of non-STR link relationships can be increased to, for example, three. In this case, the number of subfields indicating non-STR link relationships in the ML element that the STA MLD transmits to the AP MLD, as shown in Figure 11, increases from two to three. That is, a non-STR Link3 subfield is added after the non-STR Link2 subfield shown in Figure 11.

[0189] 《STA MLD Wireless Link Selection》 The STA MLD may recognize the primary link set by the AP MLD, select a wireless link that is in a non-STR link relationship with it and is operational, and notify the AP MLD of the selection result using an ML element. Alternatively, the STA MLD may recognize the primary link set by the AP MLD, select a wireless link that is in an STR link relationship with the primary link, and notify the AP MLD of the selection result using an ML element.

[0190] [A modified version of the STA MLD non-STR / STR link relationship notification] In the ML element in Figure 11, the non-STR link notifies the relationship of the non-STR link. The number of Link subfields was fixed at two. However, as explained earlier, there are cases where the notification of a link in a non-STR link relationship is omitted because the information has already been notified by other links, or when there are no wireless links in a non-STR link relationship. This section describes variations of the notification when the Link subfield contains information indicating N / A.

[0191] Figure 19 shows the format of the ML element relating to the first modified example.

[0192] The Link Information subfield consists of the Link ID subfield (1 octet), the Number Of Non-STR Links subfield (1 octet), and the Non-STR Link subfield (variable length in octets) (Non-STR Link 1, ..., Non-STR Link n in Figure 19).

[0193] The Number of Non-STR Links subfield indicates the number of links that are in a non-STR link relationship. The number of Non-STR Link subfields is the value of the Number of Non-STR Links subfield.

[0194] In this way, if the number of other wireless links with non-STR link relationships increases depending on the situation, for example, to 3 slots, STA MLD will be Number of Non-STR Flexible handling is possible by entering 3 in the Links subfield and placing three Non-STR Link subfields after the Number Of Non-STR Links subfield. If the number of links in a non-STR link relationship is 0, STA MLD enters 0 in the Number Of Non-STR Links subfield and does not place any Non-STR Link subfields.

[0195] Let's explain a second variation of efficiency improvements. Assume that STA MLD uses Link1, Link2, and Link3, similar to AP MLD, and that none of the links are non-STR links; that is, all are STR links. In this case, STA MLD can omit the Number Of Non-STR Links subfield and the Non-STR Link subfield by setting a special value in the Link ID subfield of the Link Information field in Figure 19, for example.

[0196] Let's explain a third variation. If the number of wireless links used in multilink communication is limited, then not all bits of the octet are required as the Number Of Link Information Sets subfield of the ML element shown in Figures 11 and 19, and some of those bits can be used for other purposes.

[0197] For example, if the number of wireless links is limited to 8, then only 3 bits of the Number Of Link Information Sets subfield can be allocated to represent the number of wireless links, and the number of wireless link sets can be defined as the value of the Number Of Link Information Sets subfield + 1. The "Of Link Information Sets" subfield only needs to be 3 bits long, and the remaining 5 bits can be used for other purposes. For example, if the value of the "Number Of Link Information Sets" subfield is 0, the number of wireless link sets is 1; if it is 1, the number of wireless link sets is 2; and if it is 7 (the maximum value that can be represented with 3 bits), the number of wireless link sets is 8. Therefore, one bit can be used, for example, to identify the case where all wireless links used are in an STR link relationship. In that case, the "Non-STR Link" subfield can be omitted. This shortens the notification field length of the ML element, improving efficiency.

[0198] [Understanding the non-STR link relationship between AP MLD and STA MLD] The processing of an AP MLD that receives an association request frame containing the ML elements described above is basically the same as the association process in a standard 802.11 compliant wireless LAN.

[0199] In AP MLD, the AP with MAC address AP1 passes the Frame Body information of the association request frame and the MAC address STA1 of the STA to the higher MAC processing unit 40. The higher MAC processing unit 40 passes this information to the MLME. The MLME notifies the higher MAC processing unit 40 of the instruction to generate an association response frame. The higher MAC processing unit 40 prepares the Frame Body information of the association response frame and the information of STA1 as the destination MAC address, and passes these to the AP with MAC address AP1. The AP with MAC address AP1 sends the association response frame via the first physical processing unit 32.

[0200] If the AP MLD accepts the association request from the STA with MAC address STA1, the MLME sets the Status Code of the ML element included in the association response frame to "SUCCESS". If the AP MLD rejects the association request from the STA with MAC address STA1, the MLME sets the Status Code to "REFUSED" or includes information indicating the reason for the rejection.

[0201] Furthermore, new grounds for rejection related to multilink communication may be defined. The same applies to the transmission of reassociation response frames in the reassociation process.

[0202] The AP MLD also obtains the MAC address of the STA MLD by receiving an association response frame containing an ML element. Note that although the ML element in Figure 11 directly notifies the MAC address of the STA MLD, this direct notification may be omitted.

[0203] For example, if the AP MLD can obtain the MAC address of the STA MLD by knowing the MAC address of each wireless link and some kind of regularity in that information, such as the MAC address of STA1, or by combining the MAC address of STA1, etc., with additional information, then direct notification of the MAC address can be omitted.

[0204] The AP MLD stores the acquired MAC address of the STA MLD in a memory that can be accessed commonly by the higher-level MAC processing unit 40, or by the MLME, i.e., the AP MLD.

[0205] Furthermore, the AP MLD also maintains, at least, the radio links used by the STA MLD, which are in a primary link and non-STR link relationship, as acquired by the ML element.

[0206] When AP MLD sets Link2 as the primary link, and STA MLD notifies AP MLD that Link3 is in a non-STR link relationship with Link2 (the primary link) as shown in Figure 10, AP MLD will at least retain this information and enable the following actions in AP MLD.

[0207] 《Transmission of AP MLD considering the communication status of STA MLD》 Figures 20 and 21 illustrate the operation of the AP MLD performing a downlink (DL) transmission to the STA MLD. Figure 20 shows an example of two wireless links that are in a non-STR link relationship. Here, the AP MLD notifies the STA MLD that Link1 is the primary link, and the STA MLD notifies the AP MLD that Link2 and Link1 are in a non-STR link relationship.

[0208] The AP MLD is assumed to contain, in addition to the STA MLD described above, several other STA MLDs in which Link1 and Link2 are in an STR link relationship. For convenience, here, an STA MLD in which Link1 and Link2 are in a non-STR link relationship will be referred to as non-STR MLD1, and several other STA MLDs in which Link1 and Link2 are in an STR link relationship will be referred to as STR MLDs. STR MLDs may include the AP MLD itself.

[0209] The MAC address for non-STR MLD1 is STA1 on Link1 and STA2 on Link2. The MAC address for AP MLD is AP1 on Link1 and AP2 on Link2.

[0210] Assume that AP MLD has data to send to non-STR MLD1. For example, as shown in Figure 21, suppose STR MLDs have obtained a TXOP on Link 1 ("TXOP between STR MLDs" in Figure 21) and Link 2 is free.

[0211] The AP MLD determines whether non-STR MLD1 is not communicating on Link1 (i.e., non-STR MLD1 is not a TXOP holder / responder). After confirming that non-STR MLD1 is not communicating on Link1, the AP MLD sends a DL containing a frame destined for non-STR MLD1 (see "DL including" in Figure 21). The non-STR MLD1") operation is performed on Link2. The frame can be, for example, a data frame or an RTS frame. An RTS frame is a type of control frame.

[0212] If non-STR MLD1 is communicating via Link1, non-STR Until MLD1 stops communicating on Link1, AP MLD will not send DLs containing frames destined for non-STR MLD1 on Link2.

[0213] Although this example uses a DL transmission that includes a data frame addressed to non-STR MLD1, it is also acceptable to use a DL transmission that includes only frames addressed to non-STR MLD1, or a DL multi-user (MU) transmission that includes frames addressed to other STA MLDs.

[0214] In DL transmissions over Link 2, the RA for frames destined for non-STR MLD1 is naturally STA1. In DL MU, the PHY packet notifies the Association Identifier (AID) assigned to STA2 other than STA1 using the PHY header. The PHY header is configured to identify the stream, Resource Unit (RU), or stream and the RU within it that each STA receives and decodes, and the MAC address of each STA MLD is specified in the RA within the received and decoded data frame.

[0215] If a DL transmission includes frames destined for other STA MLDs, and Link2 and Link1 in those other STA MLDs are in a non-STR link relationship, then the non-STR Similar to MLD1, the condition for executing DL transmission is that the STA MLD is not communicating via Link1. This condition is unnecessary if Link2 and Link1 are in an STR link relationship with another STA MLD.

[0216] As described above, if the AP MLD can determine whether non-STR MLD1 is communicating on Link 1 until just before it starts a DL transmission including non-STR MLD1 on Link 2 ("DL including non-STR MLD1" in Figure 21), and if it confirms that there is a transmission in progress, then delaying the DL transmission will prevent interference.

[0217] However, implementation differences can cause a time lag in the control of Link1 and Link2 by AP MLD. In this case, for example, if non-STR MLD1 has not communicated on Link1 before the Priority Interframe Space (hereinafter referred to as PIFS) is reached when a DL transmission including non-STR MLD1 is initiated on Link2, the DL transmission may be executed.

[0218] This approach cannot completely avoid interference when non-STR MLD1 devices communicate within the PIFS time, but it can minimize interference. PIFS is a frame interval (Interframe Space) that is only available under limited conditions in wireless LANs compliant with the 802.11 standard. PIFS is defined by Short Interframe Space (hereinafter referred to as SIFS) + Slot. SIFS is the minimum frame interval used when transmitting a response frame to a received data frame, and does not require understanding the carrier sense state. Slot is the smallest unit for backoff, and requires carrier sense. In the 2.4GHz band, typically SIFS is 10us, Slot is 20us, and PIFS is 30us. In the 5GHz band, typically SIFS is 16us, Slot is 9us, and PIFS is 25us.

[0219] If direct link communication is not taking place via BSS, then AP MLD can determine that a non-STR MLD1 is not communicating on Link1 (not a TXOP holder / responder) by checking whether the RA of the frame it sends contains the MAC address of the non-STR MLD1 on Link1, i.e., STA1, or, if there is a TA for the frame addressed to it, whether that TA contains the MAC address of the non-STR MLD1 on Link1, i.e., STA1. This is because the communication partner of STR MLDs on Link1 is always AP MLD.

[0220] Since direct link communication is essentially an optional feature and is used infrequently, the above criteria should suffice for determining whether or not to enable DL transmission.

[0221] Furthermore, by understanding the purpose of the application used by the connected STA MLD, the possibility of using direct link communication can be determined, and the criteria for determining whether or not DL transmission is permitted may be changed accordingly. For example, if it is determined that direct link communication is being used, the AP The MLD will also check all frames received on Link1, not just frames addressed to itself, to determine if the TA contains the MAC address of a non-STR MLD1 on Link1.

[0222] Furthermore, if AP MLD determines from the frame address that non-STR MLD1 is communicating on Link1, it will determine the end of the TXOP based on the Network Allocation Vector (hereinafter referred to as NAV) set in the Duration field of the MAC header of that frame, and will not transmit to non-STR MLD1 on wireless links that are in a Link1-non-STR link relationship, in this case Link2, until the end time.

[0223] A typical example of a frame that AP MLD sends via DL to non-STR MLD1 is a data frame. Figure 22 shows an example of the basic structure of a data frame. Like the beacon frame shown in Figure 3, the data frame includes a MAC header, a Frame Body (variable length in octets), and an FCS (4 octets).

[0224] The MAC header includes the Frame Control field (2 octets), Duration field (2 octets), Address 1 field (6 octets), Address 2 field (6 octets), Address 3 field (6 octets), Sequence Control field (2 octets), Address 4 field (0 or 6 octets), QoS Control field (0 or 2 octets), and HT Control field (0 or 4 octets).

[0225] The Frame Control field includes a Type subfield and a Subtype subfield. AP MLD uses the Type subfield as the data frame identifier and the Subtype subfield as, for example, QoS Data.

[0226] The Frame Body contains data received from higher layers.

[0227] Another example of a typical frame that AP MLD sends via DL to non-STR MLD1 is the RTS frame. Figure 23 shows an example of the basic structure of an RTS frame. An RTS frame includes a MAC header and an FCS (4 octets).

[0228] The MAC header includes the Frame Control field (2 octets), Duration field (2 octets), RA field (6 octets), and TA field (6 octets). The RA field is the address of the STA that will receive the single-destination data frame, management frame, or control frame that is scheduled to be sent after this RTS frame is transmitted. The TA field is the address of the STA that is sending the RTS frame.

[0229] The Frame Control field includes a Type subfield and a Subtype subfield. AP MLD uses the Type subfield as the identification information for the control frame and the Subtype subfield as the identifier for the RTS frame.

[0230] As described above, AP MLD determines that non-STR MLD1 is not communicating on Link1 and sends a DL to non-STR MLD1 on Link2, but non-STR MLD1 only needs to be able to receive and decode on Link2. Therefore, even if interference from Link2 leaks into Link1 via non-STR MLD1, the operation on Link1 does not affect the operation of non-STR MLD1.

[0231] As shown in Figure 21, even after the TXOP by STR MLDs ("TXOP between STR MLDs" in Figure 21) has finished, DL transmission including data frames destined for non-STR MLD1 continues on Link 2 ("DL including" in Figure 21). In the case of non-STR MLD1"), interference components from the DL transmission leak into Link1, and it is thought that the CCA becomes busy on Link1 in non-STR MLD1. However, in non-STR MLD1, there is no need for reception decoding on Link1, so no effect occurs.

[0232] In this situation, there is a possibility that the non-STR MLD1 may have trouble acquiring access rights via Link1. The solution for this will be described later.

[0233] Furthermore, if non-STR MLD1 is not communicating on Link1 and Link1 is free, AP MLD may, of course, also perform DL transmission on Link1, including frames addressed to non-STR MLD1. The frames transmitted via DL are not limited to data frames; they may also be RTS frames addressed to non-STR MLD1, or MU RTS frames (a type of trigger frame) that include non-STR MLD1 as the destination. In this case, AP The MLD may be configured so that the TXOP on Link1 terminates simultaneously with or after the TXOP on Link2 terminates. As an example of configuration, the AP MLD may include padding bits in the frames transmitted via DL on Link2.

[0234] Figure 24 shows an example of the format of an A-MPDU generated by frame aggregation. An A-MPDU consists of a sequence of n (where n is one or more) A-MPDU subframes and a single EOF Padding of variable length in octets.

[0235] Each A-MPDU subframe contains an MPDU delimiter (4 octets), followed by any MPDU (variable length in octets). All A-MPDU subframes except the last one are A-MPDU This includes padding (0-3 octets) to make the subframe length 4n octets.

[0236] EOF Padding consists of an EOF Padding subframe (4n octets) and an EOF Padding octet (0-3 octets).

[0237] AP MLD can adjust the frame length using these padding fields within the A-MPDU.

[0238] Furthermore, considering the timing of non-STR MLD1's transmission of response frames on Link1 and Link2, AP MLD may synchronize the end time of data frame transmission for DL ​​transmission on Link1 and Link2, and also synchronize the response frame length of non-STR MLD1. This allows for synchronization of data frames transmitted via DL and response frames transmitted via UL.

[0239] 《Download transmission of AP MLD trigger frames》 In the explanation for Figure 21, AP MLD transmitted a frame containing non-STR MLD1 to Link 2 via DL (Figure 21's “DL including non-STR MLD1”). This assumes DL single-user (DL SU) transmission or DL ​​multi-user (DL MU) transmission. However, an AP MLD may send a trigger frame that allows UL transmission to a non-STR MLD1 or multiple STA MLDs including non-STR MLD1s.

[0240] When AP MLD sends a frame destined for MAC address STA2 over Link 2, and STA with MAC address STA2 receives it, STA with MAC address STA2 sends a response frame such as Ack or BlockAck after SIFS to AP with MAC address AP2 via UL. The DL transmission performed by AP with MAC address AP2 over Link 2 is a DL MU containing the frame destined for MAC address STA2, and the destination STA When requesting a response frame from MLD, the AP with MAC address AP2 may include a trigger frame instructing the UL MU transmission of the response frame in its DL MU transmission. This trigger frame is of type Multi-user Block Ack Request (referred to as MU-BAR). Upon receiving the MU-BAR, each STA transmits the response frame as UL MU.

[0241] Figure 21 includes cases like this, as well as "UL including non-STR". It is labeled as "MLD1". Note that when an STA with MAC address STA2 is sending a response frame via UL on Link2, an STA with MAC address STA1 within the same non-STR MLD1 will not be able to perform carrier sense (hereinafter referred to as CS) on Link1 (see "non-STR" in Figure 21). It is thought that "MLD1 can't CS."

[0242] However, there are two types of CSs in a wireless LAN compliant with the 802.11 standard. One is the one that directly checks the busy / idle state of the wireless medium, which is the physical CS. The other is the virtual CS that sets the NAV from the end time of the PHY packet including the frame until the end time when the notified time length ends, based on the time length notified in the Duration field of the received frame. The CS when normal CS cannot be established in a wireless link related to other non-STR links while transmitting on one wireless link refers to the physical CS. In the physical CS, the CCA state is examined for busy or idle.

[0243] The trigger frame is a type of control frame. The trigger frame instructs the STA MLD to perform uplink (Up Link; hereinafter referred to as UL) MU transmission. When instructing multiple terminals to perform UL MU transmission, the frame first transmitted by the AP MLD is the trigger frame. The AP MLD uses the trigger frame to instruct the STA MLD which STA MLDs are allowed to perform UL MU transmission, what length the packet length of the UL MU transmission should be, and which MCS each STA MLD should use, etc.

[0244] When performing UL MU transmission after transmitting the trigger frame, since the AP MLD obtains the access right to access and occupy the UL channel by the trigger frame, the determination of whether it is allowed to obtain the access right on Link2 is the same as in the case of transmitting the DL frame described above by the AP MLD. If the STA MLD notifies the AP MLD in advance that there is a UL transmission request, the AP MLD can schedule the transmission of the trigger frame to the STA MLD. Furthermore, the STA MLD may request in advance which wireless link it wants to receive the trigger frame on from the AP MLD or negotiate with the AP MLD in advance which wireless link to receive the trigger frame on. In that case, Figure 21 shows the state after it is determined which link to use.

[0245] Figure 25 shows the format of a trigger frame. A trigger frame includes a MAC header, a Common Info field (8 octets or more), a User Info List field (variable length in octets), a Padding field (variable length in octets), and an FCS field (4 octets).

[0246] The MAC header field includes the Frame Control subfield (2 octets), Duration subfield (2 octets), RA subfield (6 octets), and TA subfield (6 octets). The Common Info field includes the UL Length subfield. The User Info List field includes zero or more User Info subfields, each of which includes the AID12 subfield, UL HE-MCS subfield, etc. Note that depending on the frame type, the AID subfield in the MAC header may have the same 2 octets as the Duration field and can be used in place of the Duration field. However, since the range of AIDs that the AP actually assigns to the STA is 1 to 2007, a 12-bit AID12 subfield is sufficient to represent the STA's AID in the User Info subfield of this trigger frame, and is therefore set to 12 bits.

[0247] AP MLD specifies the AID of each STA MLD in the AID12 subfield, the MCS to be used when transmitting UL MU in the UL HE-MCS subfield, and the PHY packet length in the UL Length subfield.

[0248] If the User Info field specifies a single terminal as the destination terminal for sending trigger frames, the RA will be the address of that single terminal. If the User Info field specifies multiple terminals as the destination terminals for sending trigger frames, the RA will be the broadcast address.

[0249] The AID12 subfield contains the association ID assigned to the STA MLD. The association ID specifies the STA MLD, or more precisely, the STA of the corresponding link, instead of the MAC address. After the STA MLD sends an association request frame to the AP MLD, the AP MLD sends an association response frame to the STA MLD, assigning the association ID to the STA MLD. This association ID is used by the STA MLD across all wireless links it uses.

[0250] Similar to when sending a data frame, AP MLD ensures that non-STR MLD1 is not communicating on the primary link before sending a trigger frame to non-STR MLD1.

[0251] When an STA MLD receives a trigger frame, if it has been assigned an association ID by the AP MLD and its own association ID is in the AID12 subfield, it recognizes that it is a target for UL MU transmission and performs UL MU transmission after the SIFS of the end time of the PHY packet containing the trigger frame. Furthermore, the AP MLD may transmit the trigger frame without specifying an individual STA MLD. In this case, the STA MLD receiving the trigger frame may decide whether to transmit using a random number. This transmission method is called UL OFDMA (Orthogonal Frequency Division Multiple Access) based Random Access (hereinafter referred to as UORA). In this case, for example, if non-STR MLD1 is not communicating on Link1, STA2, which receives a trigger frame specifying UORA, can transmit using UL.

[0252] 《Example of CS resume on Link1 of non-STR MLD1》 One way to avoid the possibility of collisions with other STAs when non-STR MLD1's CS doesn't function properly due to the unknown CCA status of the wireless medium on Link 1 is to, for example, suspend the execution of CSMA / CA for a fixed period of time from the time of interference on Link 2 or the termination of TXOP on Link 2, even if the CCA status on Link 1 is determined to be idle, and then execute normal CSMA / CA after the fixed period has elapsed.

[0253] In wireless LANs compliant with the 802.11 standard, when a terminal performing power saving transitions from doze to awake state or switches channels, there are cases where the physical CS does not recognize that a TXOP has already been acquired by another STA, and transmission occurs prematurely. Therefore, a fixed time called NAVSyncDelay is defined. The first method is conceptually similar to this NAVSyncDelay and may be used.

[0254] NAVSyncDelay is used in AP (when applying this to multilink communication, it is used in AP) The MLD and STA (STA MLD when applied to multilink communication) can each specify this individually, and depending on the specification, it can be made extremely short, which may be unsuitable for avoiding collisions. Also, it cannot be shared as a common time within the BSS. As a second method, a separate parameter including the value may be defined as a wireless LAN standard. Alternatively, the AP MLD may set the value of this new parameter and notify surrounding STA MLDs via beacon frames, etc. When the AP MLD notifies this fixed time length via beacon, etc., it may use, for example, the aforementioned ML element, EHT Capabilities element, or a new information element.

[0255] If, while waiting for this fixed time, other frame receptions are detected and NAV is acquired, the objective is achieved, meaning that the usage status of the wireless medium has been synchronized with other STAs, and the waiting period can be terminated.

[0256] As a third method, when restarting CSMA / CA after interference from Link2 has ended, the sensitivity may be increased compared to the conventional CS level, i.e., the CS threshold may be lowered. Conventionally, in wireless LANs compliant with the 802.11 standard, the CS level for detecting PHY packets of wireless LANs compliant with the 802.11 standard is specified as -82dBm / 20MHz, and the CS level for detecting other signals containing noise is specified as -62dBm / 20MHz. However, when restarting CSMA / CA on Link1 after interference from Link2 has ended, the physical CS level may be uniformly set to, for example, -82dBm / 20MHz. Even in this case, if it is determined that the CS state can be understood in the same way as other terminals that are performing CS normally, such as by receiving MAC frames on Link1, the operation of CSMA / CA using the normal CS threshold may be immediately returned.

[0257] In these examples, the STA with MAC address STA1 needs to know the transmission completion time of STA2 on Link2. Therefore, for example, the STA with MAC address STA2 on Link2 can share the occupied length or completion time of the PHY packets it sends with the STA with MAC address STA1 on Link1.

[0258] When an STA with MAC address STA2 transmits a response frame, the AP with MAC address AP2 can obtain the TXOP end time on Link 2 from the TXOP length, or NAV information (described later), obtained between it and the STA with MAC address STA2. Using this, the fourth method allows the STA with MAC address STA1 on Link 1 to share the TXOP length or TXOP end time. This allows the STA with MAC address STA1 to either wait a fixed amount of time from the end time or increase its CS sensitivity from the end time. For example, this information is shared from the lower MAC processing unit 38 that handles access control on Link 2 to the lower MAC processing unit 36 ​​that handles access control on Link 1.

[0259] A fifth method for the STA with MAC address STA1 to recover from a situation where it cannot accurately grasp the CS status on Link1 is for the AP MLD to notify the STA with MAC address STA2 of the NAV status on Link1 within the frame it sends to MAC address STA2 on Link2. This is because the AP MLD does not have the problem of a non-STR link relationship between Link1 and Link2. The STA MLD will use the NAV information on Link1 to determine when the TXOP on Link1 will end. For example, if the end time is earlier than the situation where the CCA cannot be grasped, it will perform a normal CSMA / CA from the moment the CCA becomes grasped without waiting for the fixed time mentioned above. If the end time is later than the situation where the CCA cannot be grasped, it will wait for the end time and then perform a normal CSMA / CA.

[0260] 《Delay in DL transmission from AP MLD to non-STR MLD1》 Figure 21 shows the case where AP MLD determines whether non-STR MLD1 is communicating on Link 1 when it sends the next data frame to non-STR MLD1, and confirms that non-STR MLD1 is sending a UL on Link 1 ("UL from non-STR MLD1" in Figure 21).

[0261] There are several ways AP MLD can respond in this situation. One example is that AP MLD will not attempt to send on Link 2 until it becomes possible to send to the STA with MAC address STA1 on Link 1. As a result, sending to non-STR MLD1 will be postponed.

[0262] A second example of how AP MLD can handle this is that if AP MLD has data destined for another STA, it will send a management frame or data frame to that STA via Link 2. This also delays the transmission of non-STR MLD1 to the STA.

[0263] Other STAs are: (1) other non-STR MLD STAs that are not transmitting on Link1, (2) other non-STR MLD STAs where Link1 and Link2 are in an STR link relationship, (3) STR MLD STAs that can maintain an STR link relationship in all wireless links in the first place, or (4) STAs that are connected to AP2 only via Link2.

[0264] There are conditions for the application of the second example. The second example can be applied when non-STR MLD1 can receive the PHY header of a PHY packet on one of two wireless links in a non-STR link relationship to obtain Automatic Gain Control (hereinafter referred to as AGC), and in a state where synchronization for reception and decoding can be obtained, and frame exchange can continue on Link1. Whether frame exchange can continue on Link1 depends on the condition of the Signal-to-Interference Ratio (hereinafter referred to as SIR).

[0265] However, depending on the implementation, there is a risk of interference with other links when participating in the TXOP of one link. For example, in a wireless LAN chip that can also transmit and receive Bluetooth (registered trademark) standard radio waves, it is conceivable that Bluetooth signals circulate through the wireless LAN antenna and the Bluetooth signals are distorted. In this case, the Low Noise Amplifier (hereinafter referred to as LNA) on the wireless LAN side may be turned off during the transmission of Bluetooth radio waves. A similar measure can be taken on Link2 when transmitting and receiving on Link1. That is, the LNA of Link2 may be turned off when transmitting and receiving on Link1.

[0266] STA-MLD may notify AP MLD in advance whether such a response is possible. STA-MLD may also notify AP MLD of this information when notifying AP MLD that two radio links are in a non-STR link relationship using ML elements, etc. STA-MLD may also notify AP MLD of this information as part of its capabilities. An example of an element that notifies this information collectively is the EHT Capabilities element. The EHT Capabilities element can also be included in association request frames and re-association request frames.

[0267] Without interfering with non-STR MLD1 communication on Link1, One method for transmitting to MLD1 via Link 2 is for the AP MLD to apply transmit beamforming to the Link 2 transmission, directing a null beam towards the non-STR MLD1's Link 1 communication (null steering). Alternatively, the 802.11ax standard Spatial Reuse (hereinafter referred to as SR) may be applied. SR is a technique that adjusts the CS sensitivity to match the transmit power of the terminal itself. Furthermore, SR is a technique that determines the resistance to interference from other terminals' own transmissions based on information obtained from the received frame, and if it is determined that the resistance is sufficient (no problem as SIR), it can transmit with overlapping timing with the received frame.

[0268] 《Transmission of wireless links in a primary link and STR link relationship using STA MLD》 When an AP MLD transmits data to an STA MLD whose Link1 and Link2 are in an STR link relationship, the STA MLD can send and receive data independently on Link1 and Link2. Therefore, the AP MLD does not need to determine whether or not the STA MLD is communicating on Link1.

[0269] As described above, according to the first embodiment, the AP MLD obtains link information of wireless links in a non-STR link relationship from the non-STR MLD. The AP MLD sets one of the wireless links in a non-STR link relationship as the primary link and notifies the non-STR MLD of the primary link information. When the AP MLD transmits to the non-STR MLD via a secondary link other than the primary link, it determines whether the non-STR MLD is communicating on the primary link or not. If the non-STR MLD is communicating on the primary link, the transmission is postponed.

[0270] This allows the AP MLD to determine whether transmission to a non-STR MLD is possible simply by checking the communication status of the primary link. Therefore, collisions between non-STR linked wireless links can be avoided, ensuring the performance of the non-STR MLD. Furthermore, the non-STR MLD can fully enjoy the benefits of multilink when no other non-STR linked wireless links exist.

[0271] (Second embodiment) In the first embodiment, the STA MLD directly notified the AP MLD which radio links were in a non-STR link relationship with a given radio link. In the second embodiment, instead of directly notifying the AP MLD which radio links were in a non-STR link relationship with a given radio link, the STA MLD indirectly notified the AP MLD of the frequency separation distance at which the two radio links would be in a non-STR link relationship or an STR link relationship.

[0272] The STA MLD notifies the AP MLD to treat two radio links whose frequency separation distance is greater than or equal to a threshold distance as non-STR links. The MLD determines which two radio links are in a non-STR link relationship based on the relationship between the link ID and link frequency of the radio links being used. When the AP MLD attempts to perform a transmission as shown in Figure 21, for example, the STA MLD determines whether Link1 and Link2 are in a non-STR link relationship or an STR link relationship based on the frequency separation distance between Link1 and Link2. The STA MLD notifies the threshold distance, and the AP MLD compares the separation distance to the threshold distance. If the separation distance is greater than or equal to the threshold distance, the AP MLD determines that the two radio links are in a non-STR link relationship.

[0273] Figure 26 shows an example of the format of ML elements included in the association request frame that STA MLD sends to AP MLD.

[0274] An ML element consists of an Element ID field (1 octet), a Length field (1 octet), an Element ID Extension field (1 octet), a STA MLD field (6 octets), and a Max Non-STR field. It includes a Frequency Difference field (1 octet), a Number of Links field (1 octet), and a Link ID Set field (variable length in octets). Note that the Number of Links field is not necessary if the Link ID subfield included in the Link ID Set field is fixed and it is guaranteed that no other fields follow the Link ID Set field. After the Non-STR Frequency Difference field, the area up to the end of the remaining ML element can be treated as the Link ID Set field, and then divided according to the fixed length of the Link ID subfield, with each part treated as a Link ID subfield.

[0275] The Max Non-STR Frequency Difference field indicates the threshold distance, which is the maximum frequency separation between two radio links that are in a non-STR link relationship. If the frequency separation between radio links is less than or equal to the threshold distance indicated by this field, the AP MLD determines that the STA MLD is in a non-STR link relationship. If the frequency separation between radio links is greater than the threshold distance, the AP MLD determines that the STA MLD is in an STR link relationship.

[0276] This field name may be changed to "Min STR Frequency Difference" to mean "the threshold distance, which is the minimum frequency separation distance required for an STR link relationship." In that case, if the frequency separation distance between wireless links is greater than or equal to the threshold distance notified in this field, the AP MLD will determine in the STA MLD that those wireless links are in an STR link relationship. If the frequency separation distance between wireless links is less than the threshold distance notified in this field, the AP MLD will determine in the STA MLD that those wireless links are in a non-STR link relationship.

[0277] In the following explanation, we will use the Max Non-STR Frequency Difference field name, but the Min STR Frequency Difference field name is also applicable; only the perspective of the notification content differs, and all other aspects are the same.

[0278] For example, the STA MLD notifies the AP MLD via the Max Non-STR Frequency Difference field that if the frequency separation distance is 240 MHz or less, the two radio links will be in a non-STR link relationship. In Figure 26, the Max Non-STR Frequency Difference field has one octet. For example, if the channel width is 80 MHz, then values ​​from 0 to 255 can represent channels in the frequency band from 0 to 20.4 GHz. If you want to represent 240 MHz as the threshold distance, the value of this field will be 3. Since it is meaningless to represent 0 MHz in this field, the value representing 0 MHz can be used for other purposes or left as Reserved.

[0279] For example, if a wireless system is only intended to cover the 2.4GHz to 6GHz band, then a threshold distance of 5GHz is sufficient. Therefore, values ​​other than those representing 5GHz should be used for other purposes or marked as Reserved.

[0280] A wireless system may use other fixed units, such as 20MHz units, instead of 80MHz units. Alternatively, a portion of the bit area of ​​this field may be used to identify the channel unit, and the remaining bit area may be used as a value representing the threshold distance.

[0281] For example, the first 3 bits could be used to identify the unit, with 0 being Reserved, 1 being 20MHz, 2 being 40MHz, 3 being Reserved, 4 being 80MHz, and 5-7 being Reserved. The remaining 5 bits could then be used to multiply the value represented by the unit to determine the frequency separation distance.

[0282] If we use a unit up to 160MHz, then for example, these 3 bits could be assigned as follows: 0 = Reserved, 1 = 20MHz, 2 = 40MHz, 3 = 80MHz, 4 = 160MHz, and 5-7 = Reserved.

[0283] If STA MLD can determine in advance, taking into account the implementation design, the range of frequency separations required for two wireless links to be in a non-STR link relationship, or the distance required for wireless links to be in an STR link relationship, then such a notification can be made.

[0284] If the former is the case, the notification method would be something like the Max Non-STR Frequency Difference field, and if the latter is the case, the notification method would be something like the Min STR Frequency Difference field.

[0285] In Figure 26, the Number of Links field and the Link ID Set field are sequentially placed after the Max Non-STR Frequency Difference field. Because the Max Non-STR Frequency Difference field is present, the Non-STR Link1 and Non-STR Link2 subfields in Figure 19 can be omitted, and therefore the field names of the ML element in Figure 19 have been changed. The `Of Links` field represents the number of Link ID subfields included in the subsequent `Link ID Set` field. The `Link ID Set` subfield consists of one or more Link ID subfields. The Link ID subfields are similar to those shown in Figure 11.

[0286] The STA MLD, among the multiple wireless links notified by the AP MLD, selects the STA The IDs of one or more wireless links used by the MLD are notified to the AP MLD using the Link ID subfield. When using two wireless links, the format in Figure 11 required 7 octets after the STA MLD field. However, the format in Figure 26 requires only 4 octets after the STA MLD field, thus reducing the field size. Reducing the field size also contributes to the efficiency of wireless communication.

[0287] The frequency separation distance notified using the Max Non-STR Frequency Difference field is, for example, the difference between the center frequencies of the channels used by each radio link. The frequency separation distance notified may be changed to represent the difference between the closest ends of the channels used by each radio link.

[0288] When AP MLD receives an association request frame containing an ML element as shown in Figure 26 from STA MLD, it compares the frequency separation distance between wireless links notified by its own device with the frequency separation distance notified in the Max Non-STR Frequency Difference field to determine which two wireless links are in a Non-STR link relationship with STA MLD.

[0289] Figure 27 shows the channels in the 5GHz band for a wireless LAN compliant with the 802.11 standard. In the case of 80+80MHz channels, two non-adjacent 80MHz channels are used as shown in Figure 27. Assume that AP MLD notifies STA MLD, for example, of channel number 106 as Link1 and channel number 138 as Link2. STA MLD notifies AP MLD via the Max Non-STR Frequency Difference field that the two wireless links will be non-STR links if the frequency separation distance is 240MHz or less.

[0290] Assuming the Max Non-STR Frequency Difference field is represented by the difference in center frequencies, AP MLD has a center frequency of 5,530 MHz for channel number 106 and a center frequency of 5,690 MHz for channel number 138, and the frequency difference between them is 160 MHz and less than or equal to 240 MHz, therefore STR In MLD, it is important to understand that Link1 and Link2 are in a non-STR link relationship.

[0291] Naturally, the STA MLD that transmits this information is also aware that Link1 and Link2 are in a non-STR link relationship as part of its own device. For example, as in the first embodiment, if the AP MLD has set Link1 as the primary link, the STA MLD will transmit using Link1 as the primary link. The AP MLD will then transmit using the STA MLD. When sending to the MLD, the system determines whether the STA MLD is communicating via Link1 and performs access rights acquisition actions based on that determination.

[0292] According to the second embodiment, the STA MLD indirectly notifies the AP MLD of wireless links that are in a non-STR / STR link relationship, thereby reducing the size of the notification information and improving communication efficiency.

[0293] (Third embodiment) In the first embodiment, the AP MLD sets one of the multiple wireless links used by its device as the primary link and notifies the STA MLD. In this embodiment, the AP MLD accepts association requests from the STA MLD to request a connection only on the primary link, thereby indirectly designating the primary link as the STA. We will notify MLD and omit the direct notification according to the first embodiment.

[0294] Specifically, when AP MLD sends an association response frame in response to an association request frame, one of the conditions for sending an association response frame with a Status Code of "SUCCESS" is that the association request frame was received on the primary link.

[0295] The association request frame, like the beacon frame in Figure 3, includes a MAC header, Frame Body, and FCS. The Type subfield of the frame control field in the MAC header contains the identification information of the management frame, and the Subtype subfield contains the identification information of the association response. The Frame Body of the association request frame includes a Status Code indicating whether the association request operation was successful or failed.

[0296] If the STA MLD sends an association request frame on a secondary link, the AP MLD sends an association response frame with a Status Code of "NG". When the STA MLD receives an association response frame with a Status Code of "NG", it recognizes that the radio link from which the association request frame was sent (or the association response frame was received) is not the primary link, and changes the radio link and resends the association request frame to request the connection again. When the STA MLD receives an association response frame with a Status Code of "SUCCESS", it recognizes that the radio link from which the association request frame was sent (or the association response frame was received) is the primary link.

[0297] By doing so, the transmission of the Reduced Neighbor Report element, which notifies the STA MLD of the primary link from the AP MLD, can be omitted, thereby improving the efficiency of wireless communication.

[0298] Figure 28 shows an example of a Status Code for a wireless LAN standard. Each Status Code is assigned to a specific value. For example, the SUCCESS code, meaning success, is assigned to 0; REFUSED and REFUSED_REASON_UNSPECIFIED, meaning failure or failure for an unknown reason, are assigned to 1; TDLS_REJECTED_ALTERNATIVE_PROVIDED, meaning Tunneled Direct Link Setup (hereinafter referred to as TDLS) wake-up schedule rejection (alternative schedule available), is assigned to 2; TDLS_REJECTED, meaning TDLS wake-up schedule rejection, is assigned to 3; and SECURITY DISABLED, meaning security is disabled, is assigned to 4. Currently, there are several Reserved values ​​to which no code has been assigned. For example, 4, 8, 9, 20, 21, ... have no code assigned to them.

[0299] Figure 29 shows an example of a Status Code in the third embodiment. The code “DENIED_NOT_PRIMARY_LINK”, which means that the link is not the primary link and is therefore rejected, is assigned to one of the currently reserved values, in this case 4. When the STA MLD sends an association request frame on the secondary link, the AP MLD sends an association response frame with a Status Code of 4.

[0300] Furthermore, when AP MLD sends an association response frame with a Status Code of 4 to STA MLD to notify STA MLD of the primary link, it may add an information element containing primary link information (such as the Channel Number) to the association response frame. This allows STA MLD to recognize the primary link without having to receive multiple association response frames with a Status Code of 4.

[0301] One way to prevent the STA MLD from sending association request frames on secondary links is for the AP MLD to send beacon frames on the primary link but not on secondary links. If beacon frames are not sent, legacy STAs will also not send association request frames. For example, if only the STA MLD corresponding to the MLO is allowed to send association request frames on secondary links, the AP MLD may send a management frame of a type not recognized by legacy STAs (with a frame type different from a beacon frame) to the STA MLD instead of a beacon frame to notify it that sending association request frames is permitted.

[0302] Even when there are multiple primary links as shown in Figure 18(a), AP MLD can accept association requests from AP MLD on the primary links Link1 and Link4, respectively, but not on the secondary links Link2 and Link3.

[0303] When AP MLD indirectly notifies Link1 and Link4 of the primary link information, STA MLD understands that Link1 and Link4 are the primary links. If STA MLD can establish a connection by sending an association request frame on Link1, it does not need to send an association request frame on Link4.

[0304] According to the third embodiment, the AP MLD does not notify the STA MLD of the identifier of the wireless link set as the primary link, but instead indirectly notifies the primary link, thereby reducing the size of the notification information and improving communication efficiency.

[0305] (Fourth embodiment) In the first embodiment, when the AP MLD performs DL MU transmission on a certain secondary link, it individually determines whether the target STA constitutes an STA MLD in which the secondary link and the primary link are in a non-STR link relationship (only MLD1 is explained in Figure 21).

[0306] In the fourth embodiment, when the AP MLD configures a PHY packet to be transmitted via DL MU on a certain secondary link, the SAT MLD that is the destination for the DL MU transmission is either an STA MLD where the secondary link and the primary link are in an STR link relationship, or an STA MLD where the secondary link and the primary link are in a non-STR link relationship. Ensure that only MLDs are used. In other words, AP MLDs ensure that the destination of PHY packets transmitted over a secondary link does not contain a mix of STA MLDs where the secondary link and the primary link are in an STR link relationship and STA MLDs where the secondary link and the primary link are in a non-STR link relationship.

[0307] To achieve this, AP MLD pre-creates a table for each secondary link that shows the STA MLD where the primary and secondary links are in a non-STR link relationship.

[0308] Depending on the STA MLD, the primary and secondary links may be in an STR link relationship or a non-STR link relationship. When AP MLD wants to send a DL over the secondary link, it can look at a table to determine whether or not it needs to check the communication status of the primary link.

[0309] Figure 30(a) shows an example of a table showing the addresses of the STA MLD group in which the primary and secondary links are in a non-STR link relationship for a given secondary link. Here, the MLD assigned to the upper MAC processing unit 40 is used as the address. MAC addresses are used. Figure 30(b) shows the MLDs of the STA MLD group where the primary and secondary links are in an STR link relationship for a given secondary link. This is a table showing MAC addresses.

[0310] In this way, when sending DL MUs to multiple STA MLDs as destinations, the communication status of the primary link can be checked all at once. When an AP MLD sends a DL MU of a PHY packet to only STA MLDs on a certain secondary link that have an STR link relationship with that secondary link and the primary link, it can omit the determination of whether the destination STA MLD is communicating on the primary link or not.

[0311] Figures 31 and 32 show other examples of tables created by AP MLD. When performing DL MU transmission and generating a MAC frame, the destination MAC address RA is required in the MAC header. Also, when performing DL MU transmission and generating a PHY packet, the association identifier AID is required in the PHY header. Therefore, AP MLD may also include this information in the table. Figure 31(a) is a table showing the MLD MAC address of the STA MLD group where the primary link and the secondary link are in a non-STR link relationship, the MAC address on the secondary link, and the AID for a certain secondary link. Figure 31(b) is a table showing the MLD of the STA MLD group where the primary link and the secondary link are in an STR link relationship for a certain secondary link. This is a table showing the MAC address, the MAC address on the secondary link, and the AID. STA1-2 shows the MAC address on the secondary link (Link2) of terminal STA MLD, which has the MLD MAC address of MLD1. AID1-2 shows the AID on the secondary link (Link2) of terminal STA MLD, which has the MLD MAC address of MLD1.

[0312] Furthermore, Figure 32 shows an example of combining Figures 31(a) and (b) into a single table. Figure 32 shows a table for each MLD MAC address that summarizes the STA MLD groups where the primary and secondary links are in a non-STR link relationship and the STA MLD groups where they are in an STR link relationship for a given secondary link. The table in Figure 32 is STA It consists of the MLD MAC address of the MLD, the MAC address of the primary link (Link1), the AID of the primary link (Link1), the MAC address of the secondary link (Link2), the AID of the secondary link (Link2), and a flag indicating whether the secondary link is a non-STR link to the primary link.

[0313] As explained above, AP MLD simplifies the decision-making process for whether DL transmission is possible by ensuring that the destination of a PHY packet transmitted over a certain secondary link does not contain a mix of STA MLDs where the secondary link and the primary link are in an STR link relationship and STA MLDs where the secondary link and the primary link are in a non-STR link relationship.

[0314] The following explains an example of how AP MLD simplifies the determination of whether DL transmission is possible, even when there is a mix of STA MLDs where the secondary link and primary link are in an STR link relationship and STA MLDs where the secondary link and primary link are in a non-STR link relationship, for PHY packets transmitted over a certain secondary link.

[0315] AP MLD groups the STAs that constitute an STA MLD, where the secondary link and primary link are in a non-STR link relationship, into the first half of the Multi-Input Multi-Output (hereinafter referred to as MIMO) stream processing order.

[0316] In this way, when AP MLD detects that it has moved from processing an STA that constitutes an STA MLD where the secondary and primary links are in a non-STR link relationship to processing an STA that constitutes an STA MLD where the secondary and primary links are in an STR link relationship, AP MLD no longer needs to check the communication status of the primary link, thus simplifying the processing.

[0317] For example, when AP MLD performs DL transmission with MU MIMO, STA is sent for each stream. An MLD is assigned. In this assignment, the AP MLD assigns an STA MLD that is in a non-STR link relationship up to the processing of a certain stream, and then assigns an STA MLD that is in an STR link relationship from the processing of subsequent streams. Up to the processing of a certain stream, the AP MLD checks whether the secondary link and primary link of the STA MLD configured by the STA are in a non-STR link relationship or an STR link relationship. If the AP MLD detects that the secondary link and primary link are in a non-STR link relationship, it must check the communication status of the primary link of the STA MLD.

[0318] However, when processing a certain stream, if it is detected that the secondary link and the primary link are in an STR link relationship, then in subsequent stream processing, since the secondary link and the primary link are in an STR link relationship, it is not necessary to determine the non-STR / STR link relationship between the secondary link and the primary link, nor is it necessary to check the communication status on the primary link.

[0319] The same applies when a wireless communication device employs OFDMA, which multiplexes by frequency. In the case of OFDMA, the AP MLD assigns RUs to the STA MLD in either descending or descending frequency order. The AP MLD assigns RUs up to a certain frequency to the STA MLD which is in a non-STR link relationship, and assigns RUs at subsequent frequencies to the STA MLD which is in an STR link relationship. Assigned to the MLD. The AP MLD processes OFDMA RUs in descending or descending order of frequency.

[0320] In this scenario, when processing OFDMA RUs, the AP MLD must, up to a certain RU, check whether the secondary and primary links are in a non-STR link relationship or an STR link relationship using the STA MLD configured by the STA. If it detects that they are in a non-STR link relationship, it must check the communication status on the primary link of the STA MLD. However, if it detects that the secondary and primary links are in an STR link relationship, then in subsequent RU processing, it is no longer necessary to determine the non-STR / STR link relationship between the secondary and primary links, and it is also unnecessary to check the communication status on the primary link.

[0321] Figure 33 is a flowchart illustrating an example of how AP MLD classifies STA MLD into two types: STA MLD where the primary and secondary links are in a non-STR link relationship, and STA MLD where the primary and secondary links are in an STR link relationship.

[0322] The AP MLD determines whether the destination of the DL MU packet to be transmitted is an STA MLD group whose secondary link and primary link are in a non-STR link relationship (Figure 33, 112). If the destination is not an STA MLD group in a non-STR link relationship, the AP MLD acquires channel rights and then DL transmits a PHY packet (Figure 33, 120).

[0323] If the destination is a group of STA MLDs that are in a non-STR link relationship, the AP MLD determines whether or not TXOP has been obtained on the primary link (Figure 33, 114). If TXOP has not been obtained on the primary link, the AP MLD obtains channel rights and then sends a PHY packet via DL (Figure 33, 120).

[0324] If TXOP is acquired on the primary link, the AP MLD determines whether the destination of the PHY packet contains the same MLD as the primary link's TXOP holder / responder (Figure 33, 116). If the destination of the PHY packet does not contain the same MLD as the primary link's TXOP holder / responder, the AP MLD acquires channel rights and then DLs the PHY packet (Figure 33, 120).

[0325] If the destination of a PHY packet contains the same MLD as the primary link's TXOP holder / responder, the AP MLD will either regenerate the PHY packet to be DL-transmitted so that the destination does not contain the same MLD as the primary link's TXOP holder / responder, or postpone transmission until the TXOP on the primary link with the same MLD as the TXOP holder / responder is completed (Figure 33, 118). After this process is complete, the AP MLD acquires channel rights and then DL-transmits the PHY packet (Figure 33, 120).

[0326] (Fifth embodiment) In this embodiment, the AP MLD takes into account the frequency separation distance between radio links when selecting multiple radio links to be used for multilink communication. For example, the AP MLD selects radio links such that the frequency separation distance is greater than or equal to a certain fixed value, so that all two radio links in most of the connected STA MLDs are in an STR link relationship. The fixed value may be defined in the standard.

[0327] For example, if an AP MLD selects two wireless links, one in the 5.2GHz band and the other in the 5.3GHz band, for multilink purposes, the frequencies of these two wireless links are close together. Therefore, for most STA MLDs connected to the AP MLD, the two wireless links will be in a non-STR link relationship. To address this, the AP MLD selects wireless links with frequencies as far apart as possible, such as the 5.2GHz band and the 5.6GHz band, as a method for selecting wireless links for multilink purposes.

[0328] According to the fifth embodiment, the AP MLD selects radio links with a certain frequency separation distance or greater for multilink communication, so in the STA MLD, the relationship between radio links is less likely to be a non-STR link relationship.

[0329] (Sixth embodiment) In this embodiment, when an AP MLD connects an STA MLD, an upper limit is set on the number of STA MLDs that can be connected in a no-STR link relationship between the primary and secondary links. If the number of such STA MLD connections exceeds this limit, the AP MLD will not allow any further STA MLD connections, even if it receives an association request frame.

[0330] If the AP MLD does not allow the connection, it notifies the STA MLD of the reason using the Status Code in the association response frame. Figure 34 shows an example of a Status Code in the sixth embodiment. The code "DENIED_EXCEED_MAX_VALUE" is assigned to one of the currently reserved values, in this case 8, which means that the connection is denied because the number of STA MLD connections in which the primary and secondary links are in a non-STR link relationship has exceeded the limit. If the number of STA MLD connections in which the primary and secondary links are in a no-STR link relationship exceeds the limit, the AP MLD sends an association response frame to the STA MLD with the Status Code 8.

[0331] STA MLD can determine why an association request was rejected, thus preventing the association request frame from being unnecessarily resent.

[0332] Since different STA MLDs may use different secondary links, the maximum number of connections for each STA MLD may be limited per secondary link.

[0333] (Seventh Embodiment) In this embodiment, STA MLDs whose primary and secondary links are in a non-STR link relationship are prevented from autonomously acquiring access rights in a distributed manner via CSMA / CA. This makes it easier for AP MLDs to perform DL transmissions to such STA MLDs.

[0334] For example, there is a mechanism to improve the efficiency of AP MLD during UL MU in the 802.11ax standard, and in this embodiment, this is used to make spontaneous transmission of STA MLD difficult.

[0335] One specific example of this is making it difficult for the STA MLD to transmit frames on the primary link until it receives a trigger frame. Because the STA MLD's transmission is suppressed on the primary link, the AP MLD can more easily determine the communication status of the primary link.

[0336] Another specific example is adjusting the MU Enhanced Distributed Channel Access (hereinafter referred to as EDCA) parameters included in the Frame Body of the management frame. Figure 35 shows an example format of the MU EDCA parameter set element.

[0337] The MU EDCA parameter set element includes Element ID (1 octet), Length (1 octet), Element ID Extension (1 octet), QoS Info (1 octet), MU AC_BE Parameter Record (3 octets), MU AC_BK Parameter Record (3 octets), MU AC_VI Parameter Record (3 octets), and MU AC_VO Parameter Record (3 octets).

[0338] Each of the MU AC_BE Parameter Record (3 octets), MU AC_BK Parameter Record (3 octets), MU AC_VI Parameter Record (3 octets), and MU AC_VO Parameter Record (3 octets) includes an ACI / AIFSNF subfield (1 octet), an ECWmin / ECWmax subfield (1 octet), and a MU EDCA Timer subfield (1 octet).

[0339] The AIFSN recorded in the ACI / AIFSN subfield specifies the number of slots to be taken after SIFS. This number of slots is a fixed time before random backoff is performed in CSMA / CA. Increasing this fixed time makes access more difficult. Therefore, if the AP MLD increases this AIFSN, it becomes more difficult for the STA MLD to acquire access rights. The AIFSN can be adjusted automatically or by user settings.

[0340] (Eighth embodiment) The AP MLD may send trigger frames to the STA of its STA MLD in accordance with the conditions based on the first embodiment, on both the primary link and the secondary link which has a primary link-non-STR link relationship on the STA MLD side, but simultaneously with or partially overlapping with the sending of trigger frames to the primary link.

[0341] Based on Figure 21, the primary link is Link1. The AP MLD obtains access rights and sends a trigger frame to primary link Link1 that includes the STA MLD as the destination when the STA MLD is not communicating. Over the same period that the AP MLD is sending a trigger frame to primary link Link1 that includes the STA MLD as the destination, the AP MLD also sends a trigger frame to the secondary link, Link2, that includes the STA MLD as the destination. In other words, if the AP MLD obtains access rights to the primary link, and the secondary link is free, it will simultaneously use the secondary link to send a trigger frame to the STA MLD as the destination on both links.

[0342] The method for obtaining access rights related to the transmission of this trigger frame is the same as that for DL ​​MU transmission in the first embodiment.

[0343] To ensure that Trigger-Based PPDUs, which are UL MU transmissions, start simultaneously on both the primary and secondary links, the trigger frame end times should be the same for both links. If the secondary link's trigger frame transmission lags behind the primary link's, padding bits should be added to the primary link's trigger frame to adjust the PHY packet length and ensure the end times are the same. In addition, to ensure that Trigger-Based PPDUs on both links terminate simultaneously, the trigger-based PPDU length indicated in the trigger frames transmitted on both links should be the same. Furthermore, the Duration field value of both trigger frames (or RTS frames if access rights are acquired prior to the trigger frame) should be the same to ensure the TXOP end times are the same. If the primary link's TXOP ends earlier than the secondary link's, the secondary link's TXOP should also end at the same time as the primary link's TXOP, or within the smallest possible time difference. A CF-End can be sent to terminate the TXOP.

[0344] Trigger frames are received and transmitted simultaneously on both the primary and secondary links. After a fixed time (SIFS) of the Trigger-Based PPDU, which terminates simultaneously, the AP MLD synchronously sends response frames to the STA that sent the Trigger-Based PPDU on both the primary and secondary links. These response frames transmitted on both the primary and secondary links also have the same duration. In this way, the frame exchange sequence is maintained synchronously on both the primary and secondary links. To achieve this, the lower-level MAC processing units 36 and 38 within the AP MLD cooperate to coordinate between AP1 on Link1 and AP2 on Link2 regarding the frames to be transmitted, the timing and packet length instructed within the transmitted frames, and the TXOP length. Note that when these response frames are transmitted at the end of a TXOP, their durations do not necessarily need to be the same. This is because, although interference and CS may not function properly on the wireless link side where the TXOP terminates slightly earlier due to the TXOP not terminating synchronously, the impact is small.

[0345] (Ninth embodiment) The objective of this embodiment is the same as that of the fourth embodiment and the like. AP MLD classifies secondary links into two types. AP MLD allows the first type of secondary link to be used only by STA MLDs where the primary link and the secondary link are in a non-STR link relationship. AP MLD allows the second type of secondary link to be used only by STA MLDs where the primary link and the secondary link are in an STR link relationship.

[0346] The STA MLD notifies the AP MLD of the available links, the combinations of links that have a non-STR relationship, and the combinations of links that have a STR relationship (either notifying the non-STR combinations will show that the STR combinations are between other links, or conversely, notifying the STR combinations will show that the non-STR combinations are between other links, so either one is sufficient) using an association request frame. The AP MLD notifies each STA MLD of the links available to the STA MLD using an association response frame. For example, AP Suppose an MLD uses Link1, Link2, and Link3 for multilink communication, with Link2 being the primary link. Suppose an STA MLD notifies an AP MLD via an association request frame that it wants to use Link1, Link2, and Link3, and that Link2 and Link1, and Link2 and Link3, are in a non-STR link relationship. In this case, the AP MLD will send an association response frame to the STA MLD denying it permission to use Link1. In other words, the AP MLD prevents the STA MLD from using Link1. On the other hand, suppose another STA MLD notifies an AP MLD via an association request frame that it wants to use Link1, Link2, and Link3, and that all wireless links are in an STR link relationship. In this case, the AP MLD will send an association response frame to the STA MLD denying it permission to use Link3. In other words, the AP MLD prevents the STA MLD from using Link3. In this way, some secondary links are made available only to STA MLDs where the primary and secondary links have a non-STR relationship, while other secondary links are made available only to STA MLDs where the primary link has an STR relationship. One way AP MLD notifies STA MLDs of such restrictions on the use of secondary links is to define a new value in the Status Code of the association response frame.

[0347] Figure 36 shows an example of a Status Code in the ninth embodiment. The code “DENIED_STR_LINK,” which means that the primary and secondary links are in an STR link relationship, is assigned to one of the currently reserved values, in this case 20. In other words, the Status Code “DENIED_STR_LINK” is notified when an association request frame is sent from an STA MLD where the secondary and primary links are in an STR link relationship, and there is a rule that only STA MLDs where the secondary and primary links are in a non-STR link relationship can use the secondary link.

[0348] Furthermore, the code "DENIED_NON-STR_LINK," which means that the primary and secondary links are in a non-STR link relationship and are therefore rejected, is assigned to one of the currently reserved values, in this case 21. In other words, the Status Code "DENIED_NON-STR_LINK" is notified when there is a rule that only STA MLDs where the secondary link and primary link are in an STR link relationship are allowed to use the secondary link, but when the secondary link and primary link are in a non-STR link relationship STA This occurs when an association request frame is sent from the MLD.

[0349] Alternatively, AP MLD could pre-notify users of such restrictions on secondary links using beacon frames or probe response frames. This would avoid the inefficiency of requesting a connection without knowing the secondary link usage policy and being denied access.

[0350] By consolidating STA MLDs that have a non-STR relationship with the primary link only to a specific secondary link in this way, the AP MLD only needs to check the communication status of the primary link to handle the non-STR relationship when accessing that specific secondary link, thus simplifying the process of acquiring access rights.

[0351] (Tenth embodiment) In the above embodiment, the AP MLD independently pre-configured the primary link. In this embodiment, the AP MLD configures the primary link based on a request from the STA MLD. The AP MLD can also configure different primary links for each STA MLD, for example, if each STA MLD requests a different primary link.

[0352] As described above, the AP MLD notifies the STA MLD of the available radio links for multilink communication using the Reduced Neighbor Report element of the beacon frame. The STA MLD then notifies the AP MLD of the other radio links it requests connection to and its preferred primary link using the ML element of the association request frame.

[0353] The AP MLD determines the links to be used and the primary link, and notifies the STA MLD of the result using an association response frame. When determining the primary link, the AP MLD may reject connection requests from STA MLDs whose wireless links do not meet the constraints. The AP MLD notifies the STA MLD of the reason for rejecting the connection request by defining a new value in the Status Code of the association response frame.

[0354] Figure 37 shows an example of a Status Code in the tenth embodiment. The code “DENIED_NOT_RESTRICTION_CONDITION”, which means that the constraint is not met and therefore rejected, is assigned to one of the values ​​currently in Reserved, in this case 9.

[0355] If AP MLD configures different primary links according to STA MLD's requests, the number of primary links may become excessively large. To curb this increase in the number of primary links, AP MLD may determine the primary links to keep the number of primary links for non-STR MLDs as small as possible, for example, to 1 or 2, and may even reject STA MLD's connection requests in some cases.

[0356] According to the tenth embodiment, the processing load on the AP MLD side increases, but the STA MLD side benefits greatly because it can perform multilink communication according to its own requests.

[0357] (11th embodiment) This embodiment addresses the case where the AP MLD changes the frequency of some of the multiple wireless links used in multilink communication.

[0358] Wireless LANs compliant with the 802.11 standard include a channel switching mechanism that changes the channel used by BSS to another channel. For example, in Dynamic Frequency Selection (DFS) operation, a typical example is that if radar waves are detected on the currently used channel, the currently used communication channel must be switched to another channel.

[0359] In addition, AP MLD may change the frequency channel based on some algorithm. For example, if there is interference from other BSSs, etc., making it difficult to obtain access rights, or if QoS cannot be satisfied even if access rights are obtained, AP MLD may change the frequency channel.

[0360] In conventional channel switches, an STA MLD that was connected to a certain frequency can be connected to the destination channel without going through the association process again. However, when changing the frequency of a wireless link used in a multilink system, the relationship between that wireless link and the primary link may change from an STR link relationship to a non-STR link relationship, or vice versa, depending on the STA MLD.

[0361] Therefore, if the AP MLD changes the frequency of a radio link used in a multilink configuration, the STA MLD must notify the AP MLD that the destination radio link and the primary link will be in a non-STR / STR link relationship.

[0362] For example, after an AP MLD changes a radio link, it needs to collect information from the STA MLD that identifies the changed radio link and the primary link as non-STR / STR links. Therefore, the AP MLD creates a new type of trigger frame requesting the transmission of this information. The Common Info field of the trigger frame includes a Trigger Type subfield.

[0363] Figure 38 shows an example of the relationship between the value of the Trigger Type subfield and the type of trigger frame. For example, the value of the Trigger Type subfield is between 0 and 15. For example, a value of 0 indicates the basic type. A value of 1 indicates the type that requests a beamforming report (Beamforming Report Poll (BRP)). Similarly, values ​​up to 7 indicate the current type of trigger frame. Values ​​8 to 15 are Reserved values ​​that are not currently in use.

[0364] A new type of trigger frame that requests the transmission of information that can identify the relationship between non-STR and STR links is assigned to one of these Reserved values. For example, a value of 8 is defined to indicate a type that requests link information (Link Info Report Poll (LIRP)).

[0365] When multiple (or even a single) STA MLDs receive this new type of trigger frame from an AP MLD on a radio link, they create a frame containing information that identifies the destination radio link and the primary link as non-STR / STR links, and transmit a UL MU to the AP MLD. This allows the AP MLD to efficiently collect information from the STA MLD that identifies the modified radio link and primary link as non-STR / STR links.

[0366] STA MLD puts information about the destination wireless link (channel information and channel width, etc.) into the Trigger Dependent Common Info subframe and UL You may send a MU.

[0367] If the STA MLD obtains information about the destination wireless link from the AP MLD beforehand, it will determine the non-STR / STR link relationship between the destination wireless link and the primary link. The MLD can be notified. To achieve this, the AP MLD may, similar to the operation of a channel switch, notify the STA MLD in advance of change information indicating a change in the radio link several times, giving the STA MLD time to notify again. Specifically, the change information may be notified in beacon frames several beacon intervals in advance. Alternatively, the AP MLD may notify the STA MLD of when the radio link will be changed, giving the STA MLD time to transition to the new radio link after the change. Specifically, the STA MLD may be notified of how many cycles after the beacon interval the radio link frequency will change.

[0368] The same applies when the AP MLD adds a new wireless link that supports multilink communication. The STA MLD needs to notify the AP MLD that the newly added wireless link and the primary link will be in a non-STR / STR link relationship, and therefore needs to know when the newly added wireless link will become available.

[0369] Even when the AP MLD changes the primary link itself, the relationship with other radio links may change. Therefore, the STA MLD needs to notify the AP MLD of the non-STR / STR link relationship between the primary link that the AP MLD changed and the other radio links.

[0370] According to the 11th embodiment, even if the AP MLD changes the frequency of some of the radio links used in multilink communication, multilink communication can continue to be performed.

[0371] (12th embodiment) This embodiment addresses the case where the STA MLD changes the wireless link used for multilink communication. Sometimes, after the STA MLD has associated with the AP MLD, it may want to change the wireless link being used. After changing the wireless link, it is not necessary for the STA MLD to re-associate with the AP MLD.

[0372] One example of wireless link switching by STA MLD is when STA MLD changes a wireless link that is in a primary link-STR link relationship to a wireless link that is in a primary link-non-STR link relationship. STA MLD may sometimes be unable to use a wireless link that is in a primary link-STR link relationship due to interference from other systems, for example. In this case, STA MLD may deliberately change the wireless link from a primary link-STR link relationship to a wireless link that is in a primary link-non-STR link relationship.

[0373] For example, in the 2.4GHz band, in addition to interference from other BSSs on the same wireless LAN, there is also interference from Bluetooth signals and electromagnetic waves from microwave ovens. In such cases, STA MLD is a situation where, for example, if the primary link is in the 5GHz band, and another wireless link that has a non-STR relationship with the primary link is available in the 5GHz band as a candidate for the secondary link, the primary link will be switched to this candidate. The MLD needs to inform the AP MLD that the destination wireless link is in a primary link and non-STR link relationship.

[0374] Another example of STA MLD changing wireless links is when STA MLD changes a secondary link that is in a primary link and non-STR link relationship to another wireless link. In this case, the primary and secondary links may remain in a non-STR link relationship, or they may change to an STR link relationship.

[0375] In any case, if the STA MLD changes a radio link, it needs to notify the AP MLD that the new radio link and the primary link will be in a non-STR / STR link relationship. However, since the relationship between other radio links that have not been changed and the primary link remains unchanged, the STA MLD does not need to re-notify information about the unchanged radio links. The STA MLD may notify the AP MLD if the relationship between the new radio link and other radio links will be in a non-STR link relationship.

[0376] Another example of STA MLD changing wireless links is when STA MLD changes a wireless link that was originally the primary link to another wireless link. In this case, the AP If the MLD has configured the primary link, the STA MLD will not use that primary link, and therefore must select a radio link that will have an STR link relationship with all other radio links. Provided this is guaranteed, the STA MLD may omit information about the non-STR / STR link relationship in the change notification to the AP MLD.

[0377] When the primary link is determined by negotiation between the AP MLD and STA MLD, the constraints are unnecessary, and the STA MLD re-notifies the AP MLD of the relationship between the wireless links to be used. The primary link is then determined by further negotiation between the AP MLD and STA MLD.

[0378] STA MLD may also add newly supported wireless links. For example, it may add wireless links that AP MLD had already listed as available, but which STA MLD did not notify it of during the association process. In such cases, STA MLD will also notify AP that the newly added wireless link and other wireless links (especially the primary link) will be in a non-STR / STR link relationship. This LD will be notified.

[0379] In any of the above cases, the STA MLD may share with the AP MLD the timing of changes or additions to wireless links. If the AP MLD needs to be aware of the relationships of non-STR links, it must also be aware of the timing of those changes. Furthermore, a newly defined Link Change Indication action frame can be used to notify information related to these changes or additions. This action frame may notify information using ML elements as shown in Figures 11, 13 to 16.

[0380] Furthermore, if the relationship between the original wireless link and the modified wireless link remains unchanged in relation to the primary link, notification of the non-STR / STR link relationship for that link from the STA MLD to the AP MLD may be omitted.

[0381] Even if STA MLD had previously notified AP MLD of the non-STR / STR link relationship of all potential wireless links under AP MLD, In some cases, it may be beneficial to re-notify the AP MLD of the non-STR / STR link relationship for all potential wireless links. This is because, if the STA MLD does not actually use a wireless link (for example, if there is a wireless link for which no Traffic ID (TID) is assigned), the AP MLD may not retain information that is currently unnecessary, in order to reduce the amount of information it manages as much as possible.

[0382] According to the twelfth embodiment, even if the STA MLD changes the frequency of some of the radio links used in multilink communication, multilink communication can continue to be performed.

[0383] (13th embodiment) Within the Infrastructure BSS (Infrastructure BSS) configured under the AP, there is direct link communication where a first STA and a second STA, both associated with the same AP, communicate directly without going through the AP.

[0384] In Figure 21, when the AP MLD determines whether communication on the primary link is possible, assuming the AP MLD is involved, the AP MLD can check the recipient of the transmission or reception on the primary link and determine whether that recipient terminal is a non-STR terminal. However, in direct link communication, the AP MLD, or more precisely, the AP corresponding to the relevant wireless link within the AP MLD, does not intervene in frame exchange. Therefore, the AP MLD must observe frames other than those it is transmitting or receiving. In other words, the AP MLD must check the RA and TA for frames other than those it is transmitting or receiving to determine whether they are non-STR terminals.

[0385] One possible solution is to prohibit the use of multilink communication when direct link communication is being performed. For example, this could be prohibited by standard. Methods of prohibition include the STA MLD voluntarily restricting itself so that when multilink communication is in progress under a certain AP MLD, the STA MLD does not perform direct link communication, or the AP MLD itself could be prohibited. MLD may prohibit direct link communication using beacon frames. A new information element (for example, called an EHT Operation element) may be defined to notify of this prohibition. Current wireless LAN standards define HT Operation elements, VHT Operation elements, HE Operation elements, etc. These Operation elements are used by APs to notify BSS operation-related information. The new EHT Operation element will similarly be used by APs to notify BSS operation-related information. Note that the EHT Capability element is used by terminals (including APs and STAs) to notify terminal capabilities and is different from the EHT Operation element.

[0386] This simplifies the AP MLD's determination of whether the STA MLD is communicating on a wireless link that is in a primary link or non-STR link relationship. In other words, the AP MLD only needs to confirm that it is communicating with the other terminal (the TA of the frame destined for the AP MLD, or the RA of the frame sent from the AP MLD) on the primary link.

[0387] On the other hand, multilink communication may also be enabled for direct link communication. In this case, the STA MLD performs the same verification with the destination STA MLD as the AP MLD. That is, when multilink communication is performed between STA MLDs, the STA MLD recognizes that the multiple wireless links involved in the multilink communication are in a non-STR / STR link relationship.

[0388] In the case of TDLS, where the AP MLD is not directly involved in setting up direct link communication, the STA of the first STA MLD, one of the two STA MLDs performing direct link communication, sends a TDLS Setup Request frame for setup initiation. This frame includes information about the multiple radio links to be used, for example, and is sent via the AP MLD to the STA of the second STA MLD. The STA of the second STA MLD, having received the TDLS Setup Request frame via the AP MLD, sends a TDLS Setup Response frame via the AP MLD to the STA of the first STA MLD. If the STA of the second STA MLD accepts the direct link communication connection request, it includes information in the TDLS Setup Response frame that identifies, for example, whether the multiple radio links are in a non-STR / STR link relationship, and sends this information to the AP MLD. The STA of the first STA MLD is notified via the MLD. When performing direct link communication and multilink communication, the primary link follows the settings of the AP MLD. The primary link follows the AP MLD to ensure that the AP MLD can determine whether the desired STA MLD can transmit by observing the primary link. In addition, it is generally best to select a subset of the radio links used by the AP MLD. The first STA MLD that sends the TDLS setup request frame should have an STR relationship with all selected radio links and should behave like the AP MLD in the first embodiment, etc. If there are radio links that have a non-STR relationship with the primary link, the first STA MLD also needs to include information about the non-STR / STR link in the TDLS setup request frame. Alternatively, if both STA MLDs in a direct link always acquire access rights on the primary link and the other secondary links can transmit in synchronization with it, then both STA MLDs do not need to notify each other of the non-STR / STR link relationship, assuming that all other secondary links have a non-STR relationship with the primary link. Specific examples of these notifications can follow, for example, the notification method in the first embodiment. That is, information elements similar to those in a beacon frame may be included in the TDLS setup request frame, and information elements similar to those in an association request frame may be included in the TDLS setup response frame to provide notifications.

[0389] Legacy AP MLDs can understand data frames, but they cannot understand management frames such as TDLS setup request frames and TDLS setup response frames. Therefore, to prevent legacy AP MLDs from being involved in the configuration of direct link communication, management frames such as TDLS setup request frames and TDLS setup response frames are encapsulated within data frames before transmission. Encapsulation means placing the entire management frame within the frame body of the data frame.

[0390] When direct link communication is performed between the first STA MLD and the second STA, frame transmission between the STA MLDs is not possible before direct link communication is configured. Therefore, the first STA MLD encapsulates a management frame and sends it to the legacy AP MLD. The management frame has the address of the first STA MLD set as the source and the address of the second STA MLD set as the destination.

[0391] The legacy AP MLD extracts the management frame from the frame body of the received data frame, encapsulates the management frame in the data frame, and sends the data frame to the second STA MLD, which is the destination of the management frame.

[0392] The second STA MLD extracts the management frame from the frame body of the received data frame. Since the management frame has the address of the first STA MLD set as the source, the second STA MLD sets up direct link communication with the first STA MLD.

[0393] In the first embodiment, the AP MLD notifies the STA MLD of the information of available radio links, and the STA MLD notifies the AP MLD of which radio link to use. In this embodiment, the first STA MLD among the two STA MLDs performing direct link communication The MLD may notify the second STA MLD of the radio link to be used for direct link communication using a TDLS setup request frame, and the second STA MLD may notify the first STA MLD of the non-STR / STR link relationship using a TDLS setup response frame. However, it may not be necessary for the second STA MLD to notify the first STA MLD of the non-STR / STR link relationship. Furthermore, the first STA MLD may also notify the second STA MLD of the non-STR / STR link relationship.

[0394] The AP MLD notifies each STA MLD of available wireless links using beacon frames. Therefore, each STA MLD already has detailed information about each wireless link from the AP MLD notification, and does not need to send this information redundantly to the other party with whom it is communicating via direct link. STA MLDs communicating via direct link can exchange information about each wireless link using link identifiers.

[0395] When performing direct link communication using an off-channel radio link that is not being used by the AP MLD, it is necessary to communicate information such as the frequency position of the radio link used for direct link communication between the STA MLDs performing the direct link communication, as notified by the AP MLD.

[0396] When an AP MLD, rather than TDLS, is involved in configuring direct link communication, the AP MLD is aware of the capabilities of the two STA MLDs configuring direct link communication, including the non-STR / STR link relationship. Therefore, when each STA MLD transmits configuration information for direct link communication, even if it does not include information about the non-STR / STR link relationship of the radio links in the management frame, the APMLD can supplement this information and notify both STA MLDs configuring direct link communication.

[0397] AP MLD can determine whether the desired STA MLD is communicating on the primary link, even when direct link communications are mixed within the BSS, simply by checking the TA or RA of the frames being transmitted on the primary link (regardless of whether AP MLD is transmitting them or not).

[0398] According to the 13th embodiment, a child device can also perform direct link communication during multilink communication.

[0399] (14th embodiment) In the embodiments described above, the AP MLD independently configured the primary link, or the AP MLD configured the primary link through negotiation between the AP MLD and the STA MLD. In this embodiment, when the STA MLD acquires access rights to one of the multiple radio links used in multilink communication, i.e., acquires a TXOP and starts data exchange, it sets the radio link for which access rights have been acquired as the primary link. The AP MLD then performs actions that accept the primary link determined by the STA MLD.

[0400] For example, when multilink communication is being performed using Link1 and Link2, STA If the MLD acquires access rights first on Link1, it sets Link1 as the primary link and sends frames only on Link1. If the STA MLD acquires access rights on Link2 as well, following Link1, it will also send frames on Link2.

[0401] When an AP MLD transmits a frame to a STA MLD, it determines whether or not the STA MLD is communicating on all radio links that are in a non-STR link relationship with that STA MLD. If it is not communicating, it transmits the frame on one or more radio links.

[0402] To achieve this, the STA MLD must notify the AP MLD in advance of the non-STR / STR link relationship between the wireless links being used. The AP MLD then keeps track of this relationship for each STA MLD.

[0403] This increases the verification load on the AP MLD, but on the other hand, it increases the transmission opportunities for the STA MLD, which has a wireless link with the AP MLD that is a non-STR link. Here, such an STA MLD is a non-STR STA Let's use MLD. However, if AP MLD limits the number of wireless links that are in a non-STR link relationship with STA MLD, the number of wireless links that AP MLD needs to check can be reduced. This does not apply to wireless links that are in an STR link relationship.

[0404] In the 14th embodiment, when a non-STR STA MLD first gains access to any wireless link that is in a non-STR link relationship, the AP MLD designates it as the primary link. The AP MLD observes the communication status on at least all wireless links that the non-STR STA MLD has notified of being in a non-STR link relationship, and sequentially determines the primary link of the non-STR STA MLD, and on other wireless links that are in a non-STR relationship with that primary link, it determines that the non-STR Stop sending to STA MLD. In the fourteenth embodiment, notification of the primary link by beacon frames or the like in the first embodiment is unnecessary.

[0405] According to the 14th embodiment, the verification load on the AP MLD increases, but the transmission opportunities for the STA MLD, which has a wireless link with the AP MLD that is in a non-STR link relationship, also increase.

[0406] (15th embodiment) The above-described embodiments do not include any description of the antenna. As a fifteenth embodiment, a method for mounting the antenna will be described. This mounting method is applicable to all of the embodiments described above.

[0407] Figure 39 shows a first implementation example in which AP MLD22 (or STA MLD24A, STA MLD24B) uses a first transmitting antenna 114, a first receiving antenna 118, a second transmitting antenna 124, and a second receiving antenna 128.

[0408] In the 15th embodiment, the AP MLD22 (or STA MLD24A, STA MLD24B) has a first analog processing unit (ANA1) 33 and a second analog processing unit (ANA2) 35 added to the configuration shown in Figure 2.

[0409] The first transmitting antenna 114 is connected to the first transmitting antenna connector 112 of the AP MLD22. The first receiving antenna 118 is connected to the first receiving antenna connector 116 of the AP MLD22. The second transmitting antenna 124 is connected to the second transmitting antenna connector 122 of the AP MLD22. The second receiving antenna 128 is connected to the second receiving antenna connector 126 of the AP MLD22.

[0410] The first analog processing unit (ANA1) 33 is connected to the first physical processing unit 32. The second analog processing unit (ANA2) 35 is connected to the second physical processing unit 34. Each of the analog processing units 33 and 35 includes a transmission system processing unit and a reception system processing unit.

[0411] The transmission system processing units of analog processing units 33 and 35 convert the PHY packets, which are digital signals output from physical processing units 32 and 34, into analog signals with a frequency corresponding to the wireless link. The analog signal output from the transmission system processing unit of the first analog processing unit 33 is supplied to the first transmitting antenna 114 via the first transmitting antenna connector 112 and transmitted from the antenna 114. The analog signal output from the transmission system processing unit of the second analog processing unit 33 is supplied to the second transmitting antenna 124 via the second transmitting antenna connector 122 and transmitted from the antenna 124.

[0412] The analog signal received by the first receiving antenna 118 is input to the receiving system processing unit of the first analog processing unit 33 via the first receiving antenna connector 116. The analog signal received by the second receiving antenna 128 is input to the receiving system processing unit of the second analog processing unit 33 via the second receiving antenna connector 126. The receiving system processing units of the analog processing units 33 and 35 convert the analog signals received by the receiving antennas 118 and 128 into digital signals so that they can be processed by the physical processing units 32 and 34.

[0413] Thus, in the first implementation example, the first transmitting antenna 114 is used for transmission on Link 1, the first receiving antenna 118 is used for reception on Link 1, the second transmitting antenna 124 is used for transmission on Link 2, and the second receiving antenna 128 is used for reception on Link 2.

[0414] Figure 40 shows a second implementation example in which the AP MLD22 (or STA MLD24A, STA MLD24B) uses the first transmit / receive antenna 102 and the second transmit / receive antenna 104.

[0415] The first transmitting / receiving antenna 102 is connected to the first transmitting / receiving antenna connector 98 of the AP MLD22. The second transmitting / receiving antenna 104 is connected to the second transmitting / receiving antenna connector 100 of the AP MLD22.

[0416] The analog signal output from the transmission system processing unit of the first analog processing unit 33 is supplied to the first transmitting / receiving antenna 102 via the selector 94 and the first transmitting / receiving antenna connector 98, and is transmitted from the antenna 102. The analog signal output from the transmission system processing unit of the second analog processing unit 35 is supplied to the second antenna 104 via the selector 96 and the second transmitting / receiving antenna connector 100, and is transmitted from the antenna 104.

[0417] The analog signal received by the first transmitting / receiving antenna 102 is input to the receiving system processing unit of the first analog processing unit 33 via the first transmitting / receiving antenna connector 98 and selector 94. The analog signal received by the second transmitting / receiving antenna 104 is input to the receiving system processing unit of the second analog processing unit 35 via the second transmitting / receiving antenna connector 100 and selector 96.

[0418] Selectors 94 and 96 are switched by controllers included in analog processing units 33 and 35, respectively. Selector 94 is switched to switch between transmitting and receiving Link 1. Selector 96 is switched to switch between transmitting and receiving Link 2.

[0419] Thus, in this second implementation example, the first transmitting and receiving antenna 102 is used for transmission and reception of Link 1, and the second transmitting and receiving antenna 104 is used for transmission and reception of Link 2.

[0420] Figure 41 shows a third implementation example in which the AP MLD22 (or STA MLD24A, STA MLD24B) uses one transmitting antenna 90 and one receiving antenna 92.

[0421] The transmitting antenna 90 is connected to the transmitting antenna connector 86 of the AP MLD22. The receiving antenna 92 ​​is connected to the receiving antenna connector 88 of the AP MLD22.

[0422] The analog signals output from the transmission system processing unit of the first analog processing unit 33 and the analog signals output from the transmission system processing unit of the second analog processing unit 35 are supplied to the multiplexing (MUX) circuit 82. The multiplexing circuit 82 multiplexes the two analog signals into a single analog signal. The output analog signal of the multiplexing circuit 82 is supplied to the transmitting antenna 90 via the transmitting antenna connector 86 and transmitted from the antenna 90.

[0423] The analog signal received by the receiving antenna 92 ​​is input to the decryption (DEMUX) circuit 84 via the receiving antenna connector 88. The decryption circuit 84 separates the received signal according to the link frequency, supplying the received signal for Link 1 to the receiving system processing unit of the first analog processing unit 33, and supplying the received signal for Link 2 to the receiving system processing unit of the second analog processing unit 35.

[0424] Thus, in this third implementation example, a single transmitting antenna 90 is used in common for both Link 1 and Link 2 transmission, and a single receiving antenna 92 ​​is used in common for both Link 1 and Link 2 reception.

[0425] Figure 42 shows a fourth implementation example in which the AP MLD22 (or STA MLD24A, STA MLD24B) uses a single transmit / receive antenna 80. The transmit / receive antenna 80 is the AP It is connected to the MLD22's transmit / receive antenna connector 78.

[0426] The fourth implementation example adds selector 76 compared to the third implementation example.

[0427] The output of the multiplexing circuit 82 is supplied to the transmit / receive antenna 80 via the selector 76 and the transmit / receive antenna connector 78, and transmitted from the antenna 80.

[0428] The analog signal received by the transmitting / receiving antenna 80 is input to the deactivation (DEMUX) circuit 84 via the transmitting / receiving antenna connector 78 and the selector 76.

[0429] Selector 76 is switched by controllers included in analog processing units 33 and 35, respectively. Selector 76 can be switched to switch between transmitting Link 1 and Link 2 and receiving Link 1 and Link 2.

[0430] Thus, in this fourth implementation example, a single transmitting antenna 90 is used for both Link 1 and Link 2 transmission and reception.

[0431] It should be noted that the present invention is not limited to the embodiments described above, and the components can be modified and implemented in practice without departing from the spirit of the invention. Furthermore, various inventions can be generated by appropriately combining the multiple components disclosed in the embodiments. For example, some components may be deleted from all the components shown in the embodiments. Moreover, components from different embodiments may be appropriately combined. [Explanation of Symbols]

[0432] 22…AP MLD, 24A,24B…STA MLD, 32,34…Physical Processing Unit, 36,38…Lower MAC Processing Unit, 40…Upper MAC Processing Unit, 44…Management Entity

Claims

1. Connect to another wireless communication device via the first link and the second link, transmit a first frame that notifies the frequency position of the first link and the frequency position of the second link, and that one of the first link and the second link is set as the primary link, and perform at least one of the first, second, third, and fourth operations. There are limitations on the use of the first and second links. The first operation described above is the operation of receiving a second frame from the other wireless communication device on the primary link, The second operation described above is the operation of transmitting a third frame to the other wireless communication device over the primary link, The third operation described above is the operation of simultaneously receiving a fourth frame from the other wireless communication device on the primary link and the secondary link. The fourth operation is the operation of simultaneously transmitting a fifth frame to the other wireless communication device via the primary link and the secondary link. The secondary link is the other of the first link and the second link. The first frame described above is not transmitted on the secondary link, but on the primary link. Wireless communication device.

2. The wireless communication device according to claim 1, wherein the constraint is that when transmission is being performed on the second link, reception fails on the first link, or when transmission is being performed on the first link, reception fails on the second link.

3. The wireless communication device according to claim 1, wherein the constraint includes at least a first constraint such that reception on one of the first link and the second link is limited by transmission on the other of the first link and the second link.

4. The wireless communication device transmits to other wireless communication devices third information indicating that it is capable of operating on the first and second links, and fourth information indicating restrictions on the use of the first and second links. Upon receiving notification from the other wireless communication device that either the first link or the second link has been set as the primary link, The first link and the second link connect to the other wireless communication device, A wireless communication device that, based on the fourth piece of information, acquires access rights to the other wireless communication device on the primary link, and then acquires access rights to the other wireless communication device on the secondary link, which is the other of either the first link or the second link.

5. The wireless communication device according to claim 4, which postpones the transmission of a frame destined for the other wireless communication device on the secondary link if the destination address or source address of the communication on the primary link includes the address of the other wireless communication device.

6. The wireless communication device according to claim 5, wherein if the transmission of a frame for which access rights have been acquired on the primary link is delayed, the transmission of a frame for which access rights have been acquired on the secondary link is also delayed.

7. The third information also indicates that it can operate on the third link along with the second link. The wireless communication device receives notification from the other wireless communication device that one of the first link, the second link, or the third link has been set as the primary link. The wireless communication device according to claim 4, wherein the two links other than the primary link among the first link, the second link, or the third link are the secondary links.

8. A first connector connectable to a first antenna for transmitting signals over the first link, A second connector connectable to a second antenna for receiving signals on the first link, A third connector connectable to a third antenna for transmitting signals over the second link, A fourth connector connectable to a fourth antenna for receiving signals on the second link, A wireless communication device according to claim 1 or claim 4, further comprising:

9. A first connector connectable to a first antenna for transmitting and receiving signals on the first link, A second connector that can be connected to a second antenna for transmitting and receiving signals on the second link, A wireless communication device according to claim 1 or claim 4, further comprising:

10. A first connector that can be connected to a first antenna for transmitting signals on the first link and on the second link, A second connector connectable to a second antenna for transmitting a signal on the first link and receiving a signal on the second link, A wireless communication device according to claim 1 or claim 4, further comprising:

11. The wireless communication device according to claim 1 or 4, further comprising a connector connectable to an antenna for transmitting a signal on the first link, transmitting a signal on the second link, receiving a signal on the first link, and receiving a signal on the second link.

12. A wireless communication method for a first wireless communication device that connects to a second wireless communication device via a first link and a second link, There are limitations on the use of the first and second links. A first frame is transmitted that notifies the frequency position of the first link and the frequency position of the second link, and that one of the first link and the second link is set as the primary link. Perform at least one of the first action, the second action, the third action, and the fourth action. The first operation described above is the operation of receiving a second frame from the second wireless communication device on the primary link, The second operation described above is the operation of transmitting a third frame to the second wireless communication device over the primary link, The third operation described above is the operation of simultaneously receiving a fourth frame from the second wireless communication device on the primary link and the secondary link. The fourth operation is the operation of simultaneously transmitting a fifth frame to the second wireless communication device via the primary link and the secondary link. The secondary link is the other of the first link and the second link. The first frame described above is not transmitted on the secondary link, but on the primary link. Wireless communication method.

13. A wireless communication method for a first wireless communication device connected to a second wireless communication device, Third information notifying that the first wireless communication device is capable of operating on the first link and the second link, and fourth information notifying that there are restrictions on the use of the first link and the second link are transmitted to the second wireless communication device. The second wireless communication device receives notification that either the first link or the second link has been set as the primary link. The first link and the second link connect to the second wireless communication device. A wireless communication method that, based on the fourth piece of information, acquires access rights to the second wireless communication device on the primary link, and then acquires access rights to the second wireless communication device on the secondary link, which is the other of either the first link or the second link.

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