Communication apparatus and communication method for multi-link traffic indication diagram

Abstract

The present disclosure provides a communication apparatus and method for a multi-link traffic indication graph, the communication apparatus being an access point (AP) of a plurality of APs affiliated to an AP multi-link device (MLD), each AP of the plurality of APs operating in a corresponding link of the AP MLD, the AP comprising: circuitry to generate a frame comprising a traffic indication graph (TIM) element and a presence bit graph, the element comprises a partial virtual bit map (PVM) indicating the presence of one or more buffered units of one of a non-AP STA or a non-AP MLD associated with the AP or the AP MLD, the presence bit map indicating whether additional information related to the one or more BUs is present in the frame for one of the non-AP STA or the non-AP MLD; and a transmitter that transmits the frame in the link.

Description

[0001] This application is a divisional application of the invention patent application filed on April 16, 2021, with application number 202180041194.8 and entitled "Communication Apparatus and Communication Method for Multi-Link Service Indication Diagram". Technical Field

[0002] This embodiment generally relates to communication apparatus, and more specifically, to a method and apparatus for a multi-link service indication diagram. Background Technology

[0003] In today's world, communication devices are expected to operate wirelessly with the same capabilities as wired computing devices. For example, users expect to seamlessly watch high-definition movies streamed to their wireless communication devices. This presents challenges for both the communication devices themselves and the access points to which they are wirelessly connected.

[0004] The Institute of Electrical and Electronics Engineers (IEEE) 802.11 Group recently established the 802.11 Task Group (TG) to address these challenges. Multilink operation in the 2.4 GHz, 5 GHz, and 6 GHz bands has been identified as a candidate technology for this type of communication. Multichannel aggregation over multiple links is a natural way to achieve a significant increase in communication data throughput.

[0005] In multi-link operations between Access Point (AP) Multilink Devices (MLDs) and non-AP MLDs, TIM elements are carried in beacon frames, traffic indication map (TIM) frames, etc., to indicate the buffered services (BUs) of the associated non-AP STAs operating in the power saving (PS) node. In multi-link operations, unlike single-link operations, the BU indication in the TIM element alone does not provide additional information about the BU, such as the recommended link for retrieving the BU or the TID associated with the BU. Methods can be used to signal additional information about the buffered BUs, such as link mappings, link set indications with recommended links, and TIDs (Traffic Identifiers). For each bit in the TIM element set to 1 to allow the non-AP MLD to correctly figure out their position in the link / TID information set, an additional bitmap is needed, regardless of the method used, which will be explained later.

[0006] Therefore, a communication apparatus and method for multi-link service indication maps are needed to address the aforementioned problems and reduce the overhead required to signal additional information about buffered BUs in a WLAN network containing MLDs. Furthermore, other desirable features and characteristics will become apparent from the following detailed description and appended claims, taken in conjunction with the accompanying drawings and the background of this disclosure. Summary of the Invention

[0007] Non-limiting and exemplary embodiments help to provide communication apparatus and communication methods for multi-link service indication diagrams.

[0008] In a first embodiment, this disclosure provides multiple access points (APs) affiliated with an AP multilink device (MLD), each of the multiple APs operating in a corresponding link of the AP MLD. Each AP includes: a circuit that generates a frame including a Traffic Indication Map (TIM) element and an Presence Bitmap, the element including a Partial Virtual Bitmap (PVM) indicating the presence of one or more buffer units (BUs) associated with the AP or AP MLD, the Presence Bitmap indicating whether additional information associated with one or more BUs is present in the frame for one of the non-AP STAs or non-AP MLDs; and a transmitter that transmits the frame in the link.

[0009] In a second embodiment, this disclosure provides a STA belonging to a plurality of stations (STAs) of a non-access point (non-AP) multilink device (MLD) associated with an AP MLD, each of the plurality of STAs operating in a corresponding link of the non-AP MLD, the STA comprising: a receiver that receives a frame in the link, the frame including a service indication map (TIM) element and an presence bitmap, the element including a partially virtual bitmap (PVM) indicating the presence of one or more buffer units for the non-AP MLD, the presence bitmap indicating whether additional information associated with one or more BUs is present in the frame for the non-AP MLD; and circuitry that processes the frame.

[0010] In a third embodiment, this disclosure provides a communication method comprising: generating a frame including a service indication map (TIM) element and an presence bitmap, the element including a virtual bitmap (PVM) partially indicating the presence of a unit in one or more buffers associated with an AP or AP MLD, the presence bitmap indicating whether additional information associated with one or more BUs is present in the frame for one of the non-AP STAs or non-AP MLDs; and transmitting the frame in a link.

[0011] Other benefits and advantages of the disclosed embodiments will become apparent from the specification and drawings. Benefits and / or advantages can be obtained individually from the various embodiments and features in the specification and drawings, and it is not necessary to provide all of these embodiments and features to obtain one or more such benefits and / or advantages. Attached Figure Description

[0012] The accompanying drawings are used to illustrate various embodiments and explain the various principles and advantages of the embodiments. In the drawings, the same reference numerals refer to the same or functionally similar elements in the various views, and the drawings, together with the following detailed description, are incorporated into and form a part of the specification.

[0013] Figure 1 It describes the TIM element and the bitmap control field of the TIM element.

[0014] Figure 2 A schematic diagram illustrating communication between an AP MLD and a non-AP MLD for multi-link power management and service indication is depicted.

[0015] Figure 3 A set of TIM bitmaps and Link Mapping Bitmaps (LMBs) is depicted.

[0016] Figure 4 The TIM bitmap and Link Recommendation (LR) elements are depicted.

[0017] Figure 5 TIM bitmap 500 is depicted in TIM elements, multi-link (ML)-TIM elements and LR elements.

[0018] Figure 6 The TIM bitmap and the Business Identifier (TID) bitmap are depicted.

[0019] Figure 7 The TIM bitmap and TID indicator are depicted.

[0020] Figure 8 A schematic diagram illustrating an example configuration of a communication device 800 according to the present disclosure is shown.

[0021] Figure 9 A flowchart illustrating a communication method for a multi-link traffic graph according to various embodiments of the present disclosure is depicted.

[0022] Figure 10 Example beacon / TIM frames are depicted.

[0023] Figure 11 Example association identifier (AID) allocations and three example TIM bitmaps are depicted, each sent by AP-MLD in three links.

[0024] Figure 12 Example TIM bitmaps, example LMB presence bitmaps, and example LMB sets are depicted in TIM / beacon frames.

[0025] Figure 13 Example TIM bitmaps, example LR presence bitmaps, and example LR bitmap sets are depicted in TIM / beacon frames.

[0026] Figure 14 Example TIM bitmaps, example link set presence bitmaps, example link set bitmaps, and example LR bitmaps are depicted in TIM / beacon frames.

[0027] Figure 15 Example TIM bitmaps, example TID information presence bitmaps, and example TID information bitmap sets are depicted in TIM / beacon frames.

[0028] Figure 16 Example TIM bitmaps, example AC information presence bitmaps, and example AC information bitmaps are depicted in TIM / beacon frames.

[0029] Figure 17 Example AID allocations and three example TIM bitmaps sent from AP MLD in three links are depicted respectively.

[0030] Figure 18 Example beacon / TIM frames are depicted.

[0031] Figure 19 Example TIM bitmaps and example LMB sets are depicted in beacon / TIM frames.

[0032] Figure 20 Another example beacon / TIM frame is depicted.

[0033] Figure 21 Example TIM bitmaps, example TID information presence bitmaps, and example TID information bitmap sets are depicted in beacon / TIM frames.

[0034] Figure 22 Example TIM bitmaps sent from AP MLD in the link, as well as example formats of AC information presence bitmaps and AC information bitmap sets, are depicted.

[0035] Figure 23 The example format of the TIM bitmap and TID information presence bitmap 2304 and the TID information bitmap in the beacon / TIM frame is described.

[0036] Figure 24 An example format for a multi-link TIM element is described.

[0037] Figure 25 Example TIM bitmaps and example multilink TIM bitmaps, example AC information presence bitmaps, and example AC information bitmaps are depicted in beacon / TIM frames.

[0038] Figure 26 An example format for multilinked TIM elements, including a multilinked TIM bitmap, is described.

[0039] Figure 27 An example configuration of a communication device and two communication devices belonging to the communication device is shown. According to this disclosure, the communication device is implemented as an AP MLD, and each subordinate communication device can be implemented as an AP configured for a multi-link traffic indication diagram.

[0040] Figure 28 An example configuration of a communication device and two communication devices belonging to the communication device is shown. According to this disclosure, the communication device is implemented as a non-AP MLD, and each belonging communication device can be implemented as a STA configured for a multi-link traffic indication diagram.

[0041] Those skilled in the art will understand that the elements in the accompanying drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some elements in the illustrations, block diagrams, or flowcharts may be exaggerated relative to other elements to aid in an accurate understanding of this embodiment. Detailed Implementation

[0042] The following detailed description is exemplary in nature only and is not intended to limit the embodiments or their application and use. Furthermore, it is not intended to be bound by any theories set forth in the foregoing background or detailed description. In addition, other desirable features and characteristics will become apparent from the following detailed description and appended claims, taken in conjunction with the accompanying drawings and the background of this disclosure.

[0043] In the context of IEEE 802.11 (Wi-Fi) technology, a station (commonly referred to as a STA) is a communication device capable of using the 802.11 protocol. Based on the IEEE 802.11-2020 definition, a STA can be any device that includes a Media Access Control (MAC) interface compliant with IEEE 802.11 and a Physical Layer (PHY) interface to the wireless medium (WM).

[0044] For example, an STA can be a laptop computer, desktop personal computer (PC), personal digital assistant (PDA), access point, or Wi-Fi phone in a wireless local area network (WLAN) environment. STAs can be fixed or mobile. In a WLAN environment, the terms "STA," "wireless client," "user," "user equipment," and "node" are often used interchangeably.

[0045] Similarly, an AP (which is interchangeably called a wireless access point (WAP) in the context of IEEE 802.11 (Wi-Fi) technology) is a communication device that allows STAs to connect to a wired network in a WLAN. An AP is typically connected to a router as a standalone device (via a wired network), but it can also be integrated with a router or used within a router.

[0046] As mentioned above, a STA can function as an AP in different situations within a WLAN, and vice versa. This is because communication devices in the context of IEEE 802.11 (Wi-Fi) technology can include both STA and AP hardware components. In this way, the communication device can switch between STA and AP modes based on actual WLAN conditions and / or requirements.

[0047] In various embodiments of this disclosure, a multi-link device (MLD) can refer to a device operating in two or more frequency bands or links (2.4 GHz, 5 GHz, or 6 GHz). An MLD may include two or more communication devices corresponding to two or more links, each operating in a specific frequency band or link. For simplicity, each link of the MLD shown in this disclosure is associated with one of a plurality of communication devices belonging to the MLD, which primarily operates in a specific frequency band (2.4 GHz, 5 GHz, or 6 GHz) to transmit / receive signals to / from another communication device not belonging to the MLD but also operating in that specific frequency band.

[0048] In various embodiments of this disclosure, unless otherwise specified, a non-MLD STA, 11n STA, 11ac STA, or 11ax STA may refer to a conventional (HE / VHT / HT) STA or EHT STA that is not affiliated with an MLD. Similarly, a non-MLD AP may refer to an EHT AP that is not affiliated with an MLD.

[0049] In various embodiments of this disclosure, the Partial Virtual Bitmap (PVM) field refers to the bitmap of a Service Indication Map (TIM) element carried in a frame transmitted by the AP or AP MLD in the link, and the terms “PVM” or “partial virtual bitmap” are used interchangeably with TIM bitmap.

[0050] The beacon frame carries a Service Indication Map (TIM) element to indicate buffered services (BU) of non-APSTA that operate in power saving (PS) mode. Figure 1 The bitmap control fields of TIM element 100 and TIM element 100 are depicted. TIM element 100 includes an element identifier (ID) field, a length field, a delivery TIM (DTIM) count field, a DTIM time period field, a bitmap control field 102, and a partial virtual bitmap (PVB) field. Bitmap control field 102 includes a service indicator field and a bitmap offset field. The length field is set to... ,in It is the largest even number, such that the numbers in the service indication virtual bit diagram are numbered from 1 to ( All bits of x 8) – 1 are 0, and It is the smallest number, so that the number in the service instruction virtual bit diagram is ( + 1) All bits from ×8 to 2007 are 0, and the TIM bit is set to 0 at either end of the AID range. and Used to signal the actual range of the TIM bitmap carried in the PVB field. For AID, the PVB field is set to 1 to indicate the presence of a buffered BU for that AID. When one or more Group Addressed Media Access Control (MAC) Service Data Units (MSDUs) / MAC Management Protocol Data Units (MMPDUs) are buffered at the AP, the service indicator in the TIM element is set to 1, where the DTIM count field is set to 0. A TIM element where the DTIM count field is set to 0 when one or more group-addressed MSDUs / MMPDUs are buffered at the AP. The bitmap offset field contains a number. .

[0051] For multi-link power management, each STA of a non-AP MLD operating on an enabled link maintains its own power management mode and power state. Each STA of a non-AP MLD can independently change its power management mode or its power state. Figure 2 A schematic diagram 200 illustrates communication between an AP MLD 202 and a non-AP MLD 204 for multi-link power management and service indication. Frame switching is possible on an enabled link when a STA (e.g., STA 1, STA 2) of a non-AP MLD 204 operating in an active or power-saving wake-up state (e.g., configured with the PM (Power Management Mode) field value 0); and if the AP MLD 202 has buffered services (BUs) of associated non-AP MLD 204's subordinate STAs (e.g., STA 1, STA 2), the corresponding subordinate AP (e.g., AP 1, AP 2) on the AP MLD 202 operating in a power-saving sleep state (e.g., configured with the PM (Power Management Mode) field value 1) will use the TIM element carried in the beacon frame to indicate the non-AP MLD 204's buffered services.

[0052] TID-to-link mapping is a new mechanism introduced in 802.11be that allows APMLDs and non-AP MLDs that have performed multi-link establishment to determine how to map TIDs to established links in the downlink (DL) and uplink (UL). By default, all TIDs are mapped to all established links in both the UL and DL. If a TID is mapped to a link in a specific direction (DL / UL), then transmission of frames belonging to that TID is permitted in that direction.

[0053] An established link is defined as enabled if at least one TID is mapped to it, and an established link is defined as disabled if no TID is mapped to it. At any given time, unless permission control is used, a TID will always be mapped to at least one established link. By default, all established links are enabled because all TIDs are mapped to all established links.

[0054] If a TID is mapped in the UL to an enabled link set for a non-AP MLD, the non-AP MLD can use any link within the enabled link set to send frames carrying an MSDU or A-MSDU with that TID. If a TID is mapped in the DL to an enabled link set for a non-AP MLD, the non-AP MLD can retrieve a buffer BU corresponding to that TID on any link within the enabled link set, while the AP MLD can use any link within the enabled link set to send frames carrying an MSDU or A-MSDU with that TID, depending on existing restrictions on frame transmission applicable to those enabled links.

[0055] Traditionally, the TIM element is used as is. For non-AP MLDs, the TIM bit is assigned to each non-AP MLD regardless of the number of established links; that is, a single AID is assigned to non-AP MLDs on all links. If the AP MLD has no buffered frames to send to a non-AP STA / MLD, the TIM bit for the non-AP STA / MLD is set to 0, and if the AP MLD has one or more buffered frames to send to a non-AP STA / MLD on any link it is using, the TIM bit is set to 1. According to the IEEE 802.11-2020 specification, any value in the range 1-2007 can be used as the AID of an associated STA; however, in the various examples used in this disclosure, the AP MLD allocates AIDs in the range 1-255 to its associated non-AP STAs and non-AP MLDs.

[0056] On top of the traditional TIM element, another element is defined, such as an element carrying LMB, to indicate the buffered data to link mapping of each non-AP MLD whose TIM bit is set to 1.

[0057] Figure 3The TIM bitmap 300 and LMB set 302 are depicted within the TIM elements. Each bit in the TIM bitmap, except for AID 0, corresponds to the AID of a non-AP STA / MLD. TIM bits corresponding to AIDs 12, 28, 35, 57, and 77 are set to 1, indicating that the AP MLD has one or more buffered frames to send to the corresponding STA / MLD associated with that AID. For each bit set to 1 in the TIM bitmap 300, there exists an LMB. This is to allow non-AP MLDs to calculate the position of their LMBs in the LMB set 302 based on the order of the bits set to 1 in the TIM bitmap 300. Traditionally, even for traditional STAs, LMBs are needed to ensure that non-AP MLDs can correctly locate their LMBs, since it is impossible to identify a traditional STA based on the TIM bitmap 300. In one example, the number of bits in an LMB corresponds to the number of enabled links for the non-AP MLD.

[0058] When a non-AP MLD identifies that the TIM bit corresponding to its AID is set to 1 in the TIM element, the non-AP MLD also checks the LMB corresponding to the AID and identifies the specific links to which the buffered service is mapped. For example, a non-AP MLD with AID 28 identifies that its TIM bit is set to 1, therefore the AP MLD has its buffered service in one of its enabled links. The non-AP MLD then identifies that its LMB is the second bit in sequence (the second bit set to 1 in the TIM bit map) and checks the second LMB in LMB set 302. The non-AP MLD then identifies that the second and third bits of its LMB are set to 1, indicating that the AP MLD has the non-AP MLD's buffered service in links 2 and 3.

[0059] In another traditional example, AIDs are assigned to non-AP MLDs, and the TIM element indicates the BU status for each non-AP MLD. Under the default TID-to-link mapping, TIDs are mapped to all enabled links. When the bit in the TIM element corresponding to the AID of a non-AP MLD is set to 1, although the non-AP MLD can retrieve buffered data through any of the enabled links, the AP MLD can use the LR element to indicate the recommended link(s). The bitmap in the LR element is assigned to non-AP MLDs, where each bit of the bitmap is mapped to a link and indicates whether the link is recommended.

[0060] Figure 4TIM bitmap 400 and LR element 402 are depicted. In TIM bitmap 400, TIM bits (bits 1 and 3) associated with the AIDs of non-AP MLD 1 and non-AP MLD 3 are set to 1, indicating that AP MLD has one or more buffered frames to send to non-AP MLD 1 and non-AP MLD 3. LR element 402 comprises a bitmap of each bit set to 1 in TIM element 400, in which case, bits... Figure 1 and bit Figure 3 These indicate the recommended links for non-AP MLD 1 and non-AP MLD 3, respectively. In one example, the number of bits in the LR bitmap corresponds to the number of enabled links for the non-AP MLD. Figure 1 Having values ​​"1", "0", and "0", it indicates that the first link is recommended to the non-AP MLD to retrieve buffered frames from the AP MLD; and the bit Figure 3 With values ​​“0”, “0”, and “1”, it indicates that a third link is recommended to non-AP MLD 3 to retrieve buffered frames from AP MLD.

[0061] In addition to the default TID-to-link mapping, two or more links can be categorized into link sets, and different TIDs can be mapped to different link sets. The BU status of different link sets can be indicated using the new Multi-Link (ML) TIM element. The bitmap in the ML TIM element is assigned to non-AP MLDs. Each bit of the bitmap is mapped to a link set and indicates the BU status; for example, it is set to 1 if one or more BUs exist, and set to 0 if no BU exists for the link set. The LR element can also be used to indicate recommended links within a link set.

[0062] Figure 5 TIM bitmap 500, ML-TIM element 502, and LR element 504 are depicted. TIDs 0-3 are mapped to a first link set including link 1 and link 2, while TIDs 4-7 are mapped to a second link set including link 3. The TIM bits (bits 1 and 2) corresponding to the AIDs of non-AP MLD1 and non-AP MLD2 are set to 1, indicating that the AP MLD has one or more buffered frames to send to non-AP MLD1 and non-AP MLD2. ML-TIM element 502 includes a bitmap of each bit in the TIM element set to 1, in which case the bits... Figure 1 and bit Figure 2 These indicate the BU status of different link sets, namely non-AP MLD 1 and non-AP MLD 2. The number of bits in ML-TIM bitmap 502 corresponds to the number of link sets. Figure 1Having values ​​"1" and "0", it indicates that the first link set has a BU for non-AP MLD 1; and the bit Figure 2 It has values ​​"0" and "1", which indicate that the second link set has a BU for non-AP MLD 2.

[0063] LR element 504 also includes a bitmap indicating recommended links within the link set, bits Figure 1 It has values ​​"0" and "1" to indicate the recommended link in the second link of link set 1 (i.e., link 2, which is not AP MLD 1). Because the bit Figure 2 This indicates the second link set for non-AP MLD2, and the second link set contains only a single link (link 3), so link 3 is recommended for non-AP MLD2 and a separate LR element is not required.

[0064] In another traditional example, AIDs are assigned to non-AP MLDs, and the TIM element indicates the BU status for each non-AP MLD. For a non-AP MLD, the TID bitmap (8 bits per TID) with each bit set to 1 in the TIM element indicates that the AP MLD has one or more TIDs for one or more BUs (multiple) of the non-AP MLD. Each bit in the TID bitmap represents a TID starting from TID 0, and a bit set to 1 indicates that a buffered frame belonging to the corresponding TID exists at the AP MLD. The STA uses the TID-to-link mapping to determine which link(s) it should wake up to retrieve the buffered MPDU (MAC Protocol Data Unit). In this example, it is assumed that different TIDs are mapped to different links.

[0065] Figure 6TIM bitmap 600 and TID bitmap 602 are depicted within the TIM element. In TIM bitmap 600, the TIM bit corresponding to one non-AP STA under AID 27 and five non-AP MLDs under AID 12, 28, 35, 57, and 77 is set to 1 to indicate that the AP MLD has one or more buffered frames to send to the corresponding STA and MLD, respectively. For each TIM bit set to 1 in the TIM element for a non-AP MLD, there is an 8-bit TID. In this case, TID bitmap 602 includes five 8-bit TIDs for the five corresponding non-AP MLDs, which the AP MLD has one or more buffered frames to send to. The 8-bit TID will be used by the corresponding non-AP MLDs to determine which link(s) they should wake up to retrieve the buffered MPDU from the AP MLD. However, in this example, it is unclear whether a TID indication is also needed for a conventional non-AP STA with AID 27; without it, non-AP MLDs with AID greater than 27 will not be able to determine the correct TID indication for themselves.

[0066] Instead, the AP uses a 3-bit TID bitmap 602 instead of an 8-bit TID bitmap to signal individual TIDs. Figure 7 The TIM bitmap 700 and TID 702 in the TIM element are depicted. A 3-bit TID is signaled to each STA / MLD. Each STA / MLD's AID corresponds to a TIM bit set to 1. If frames belonging to multiple TIDs are buffered at the AP MLD for non-AP MLDs, the signaled TID can be based on certain implementation-specific standards. The AP delivers an MPDU belonging to the indicated TID on the link woken by the STA / MLD, and carries an A-Control (TID control) field in the MPDU, which signals to the AP that it has an additional TID for the BU for non-AP MLDs. It is important to note that legacy STAs also require the TID indication so that non-AP MLDs can find the correct TID indication, even if the legacy STA is unaware of the TID indication.

[0067] As mentioned earlier, regardless of the method used to signal additional information about the buffer BU (e.g., ... Figures 3-7The link mapping shown, the link set indication with link recommendation, and the TID indication (as illustrated) require an additional bitmap for each bit set to 1 in TIM elements (including traditional STAs and non-MLD EHT STAs) so that non-AP MLDs can correctly determine their position in the link / TID information set. Therefore, a communication device and method for multi-link service indication maps is needed to address this problem and reduce the overhead required to signal additional information about buffered BUs in WLAN networks containing MLDs.

[0068] According to this disclosure, two solutions are proposed. Specifically, an presence bitmap is carried in the beacon / TIM / FILS discovery / OPS frame to indicate whether the corresponding link / TID / AC information associated with the buffer BU of the non-AP STA / MLD exists in the link / TID / AC information set. Even if this bit is set to 0, the presence bitmap can still carry implicit information about the link.

[0069] In addition, a “Starting AID” field is carried in the beacon / TIM / FILS discovery / OPS frame to indicate the smallest AID (e.g., the AID of the first non-AP MLD) associated with the link / TID / AC information included in the link / TID / AC information set. Different portions (e.g., AID space) can be reserved for assigning AIDs to legacy STAs / non-MLD Extremely High Throughput (EHT) STAs and to non-AP MLDs to further reduce the overhead of the link / TID / AC information set.

[0070] Figure 8 A schematic diagram illustrating an example configuration of a communication device 800 according to this disclosure is shown. According to this disclosure, the communication device 800 can be implemented as an AP and a STA, and configured for multi-link service indication. (See diagram below.) Figure 8 As shown, the communication device 800 may include circuitry 814, at least one radio transmitter 802, at least one radio receiver 804, and at least one antenna 812 (for simplicity and for illustrative purposes, in...). Figure 8(Only one antenna is depicted in the image). Circuit 814 may include at least one controller 806 for software and hardware-aided execution of tasks designed to be performed by the at least one controller 806, including controlling communication with one or more other communication devices in a multiple-input multiple-output (MIMO) wireless network. Circuit 814 may also include at least one transmit signal generator 808 and at least one receive signal processor 810. The at least one controller 806 may control the at least one transmit signal generator 808 for generating MAC frames (e.g., data frames, management frames, and action frames) to be transmitted via at least one radio transmitter 802, and the at least one receive signal processor 810 for processing MAC frames (e.g., data frames, management frames, and action frames) received via at least one radio receiver 804 from one or more other communication devices. Figure 8 As shown, at least one transmit signal generator 808 and at least one receive signal processor 810 may be independent modules of the communication device 800, which communicate with at least one controller 806 to achieve the above-described functions. Alternatively, at least one transmit signal generator 808 and at least one receive signal processor 810 may be included in at least one controller 806. It will be apparent to those skilled in the art that the arrangement of these functional modules is flexible and can vary according to actual needs and / or requirements. Data processing, storage, and other related control devices may be provided on a suitable circuit board and / or chipset. In various embodiments, when in operation, at least one radio transmitter 802, at least one radio receiver 804, and at least one antenna 812 may be controlled by at least one controller 806.

[0071] Communication device 800 provides the functionality required for a multi-link traffic indication map. For example, communication device 800 may be an AP belonging to a plurality of APs in an AP MLD, where each AP operates in a corresponding link of the AP MLD, and circuitry (e.g., at least one transmit signal generator 808 of circuitry 814) may generate frames including a traffic indication map (TIM) element and an presence bitmap, the element including a partially virtual bitmap (PVM) indicating the presence of one or more buffer units associated with the AP or AP MLD, or one of the non-AP STAs or non-AP MLDs, indicating whether additional information associated with one or more BUs is present in the frame for one of the non-AP STAs or non-AP MLDs. Radio transmitter 802 may transmit frames in the link.

[0072] For example, communication device 800 may be a STA belonging to one of a plurality of STAs in a non-AP MLD associated with an AP MLD, each of the plurality of STAs operating in a corresponding link in the non-AP MLD, and radio receiver 804 may receive a frame on the link that includes a Traffic Indication Map (TIM) element and an Presence Bitmap, the element including a Partial Virtual Bitmap (PVM) indicating the presence of one or more buffer units in the non-AP MLD, the Presence Bitmap indicating whether additional information associated with one or more BUs is present in the frame in the non-AP MLD. The circuitry (e.g., at least one receive signal processor 810 of circuitry 814) may process the frame.

[0073] In one embodiment, the frame sent / received by the communication device 800 also includes a Start Association Identifier (AID), which indicates the smallest AID in the frame that indicates additional information associated with one or more BUs. In another embodiment, a first portion of the PVM in the TIM element is associated with an AID assigned to a traditional STA and a non-MLD EHT STA, and a second portion of the PVM in the TIM element is associated with an AID assigned to a non-AP MLD, wherein the first and second portions of the TIM element do not overlap.

[0074] Figure 9 A flowchart 900 illustrating a communication method for a multi-link service graph according to various embodiments of the present disclosure is depicted. In step 902, a step is performed to generate a frame including a Service Indication Graph (TIM) element and an Presence Bitmap, the element including a Partial Virtual Bitmap (PVM) indicating the presence of one or more buffer units associated with an AP or AP MLD, the Presence Bitmap indicating whether additional information associated with one or more BUs is present in the frame for one of the non-AP STAs or non-AP MLDs. In step 904, a step is performed to transmit the frame in the link.

[0075] Figure 10Example beacon / TIM frame 1000 is depicted. Although the format of the beacon / TIM frame is shown, it will be understood that the same format can be applied to Fast Initial Link Setup (FILS) discovery frames or Operation (OPS) frames. Beacon / TIM frame 1000 carries TIM element 1002, which includes a Partial Virtual Bitmap (PVM) 1008, a Link / TID / AC Information Presence Bitmap 1004, and a Link / TID / AC Information Set 1006 including Link / RID / AC information for each associated MLD. Presence Bitmap 1004 indicates whether the corresponding Link / TID / AC information associated with the buffer BU used for non-AP MLDs is present in Link / TID / AC Information Set 1004.

[0076] Existence bitmap 1004 carries 1 bit for each bit set to 1 in TIM element 1002 in the same order as in PVB 1008. If the corresponding entry for the link / TID / AC information exists in the link / TID / AC information set 1006, the bit in existence bitmap 1004 is set to 1; otherwise, it is set to 0.

[0077] The bits corresponding to a traditional STA are always set to 0; however, if for an MLD, the link / TID / AC information exists in the link / TID / AC information set 1006, for example, if the AP MLD has a BU that is buffered for a non-AP MLD in other links, or if the AP MLD recommends that a non-AP MLD retrieve a BU in another link, or if the AP MLD needs to signal a BU mapped to a TID on another link, then the bits corresponding to the MLD are set to 1; and otherwise they are set to 0, for example, if the AP MLD has a BU that is buffered for a non-AP MLD in the same link (here referred to as the "current link," or also the "transmitting link") that sends a TIM / beacon frame 1000 carrying TIM elements, or if the AP MLD recommends that a non-AP MLD retrieve a BU in the current link, or if all BUs of a non-AP MLD belong to a TID dedicated to mapping to the current link, or for a single-link EHT STA or a single-link non-AP MLD that listens for beacons only on one link, its bits are set to 0 in all links. Advantageously, bits set to 0 still carry implicit information about the current link, and link / TID / AC information exists only for MLDs that need it. Using the presence bitmap 1004 in the beacon / TIM frame 1000, if its corresponding bit in the PVB 1008 is set to 1, the non-AP MLD then checks its corresponding bit in the presence bitmap 1004, and if its bit in the presence bitmap 1004 is set to 1, it then further checks the corresponding entry in the link / TID / AC information set 1006 for further information about the BU associated with the link / TID / AC.

[0078] According to this disclosure, the same AID is assigned to the MLD on all links, but a unique AID is assigned to the legacy STA on each link; that is, the same AID can be assigned to different legacy STAs on different links. Advantageously, there are no restrictions on how the APMLD assigns AIDs.

[0079] Figure 11 Example AID allocations and three example TIM bitmaps 1100, 1110, and 1120, respectively, sent by AP-MLDs on three links, are depicted. MLDs 1, 2, and 3 operating on all three links (link 1, link 2, and link 3), as well as single-link MLD 4, are assigned the same AIDs 12, 28, 57, and 77 on the three links, respectively; while traditional STAs are assigned unique AIDs on their respective operating links. Notably, the same AID 35 is assigned to different traditional STAs (traditional STA 1 and traditional STA 2) on links 1 and 2, respectively, while AID 35 is not assigned on link 3. (The following is a continuation of the previous paragraph.) Figures 12-16In the description, various embodiments of this disclosure are based on example AID allocation for example TIM bitmap 1100.

[0080] In one embodiment, Figure 10 The bitmap 1004 shown can be a link mapping bitmap (LMB), and Figure 10 The link / TID / AC information set 1006 shown is an LMB set, where the presence bitmap indicates whether the corresponding LMB exists in the LMB set. Bits corresponding to traditional STAs are always set to 0; however, if a BU is only available on the link sending TIM / beacon frames carrying TIM elements, the bits corresponding to MLDs are set to 0, for example, due to TID-to-link mapping or MLDs operating only on that link, and if the BU is also available on other links, they are set to 1. The LMB presence bitmap carries bits for each bit set to 1 in the TIM bitmap in the same order as the TIM bitmap, and the LMB set carries LMBs for each bit set to 1 in the LMB presence bitmap in the same order as the LMB presence bitmap. Advantageously, bits set to 0 in the LMB presence bitmap indicate that the corresponding non-AP MLD only needs to retrieve the BU in the current link, and the LMB is not needed in the LMB set, reducing the overhead of link / TID / AC information.

[0081] Figure 12 Example TIM bitmap 1200, example LMB presence bitmap 1202, and example LMB set 1204 are depicted in TIM / beacon frames. In TIM bitmap 1200, the TIM bits corresponding to AIDs 12, 28, 35, 57, and 77, respectively assigned to MLD 1, MLD 2, Traditional 1, MLD 3, and Single Link MLD 4, are set to 1, indicating that the AP MLD has one or more buffered frames to send to those STA / MLDs. LMB presence bitmap 1202 carries bits for each bit set to 1 in the same order as in TIM bitmap 1200, thus LMB presence bitmap 1202 has a total size of 5 bits.

[0082] In this example, the AP MLD sending the TIM / beacon frame operates on three links (link 1, link 2, and link 3), and the TIM / beacon frame sent on link 1 (here referred to as the current link) is shown. In this example, MLD 1 only has a BU mapped to the TID of link 1, while MLD 4 operates only on link 1. Since the BUs for the TIDs of MLD 1 and MLD 4 are mapped to the current link (link 1), no additional information for MLD 1 and MLD 4 is required, and the LMBs in the LMB set exist or are required only for MLD 2 and MLD 3. The first and fifth bits corresponding to MLD 1 and MLD 4 in LMB presence bitmap 1202 are set to 0 to indicate that the BU is available only on the current link (link 1); while the second and fourth bits corresponding to MLD 2 and MLD 3 in LMB presence bitmap 1202 are set to 1 to indicate that their BUs are also available on another link (link 2, link 3). Traditional 1 is a traditional STA, therefore the third bit corresponding to traditional 1 in the LMB existence bit diagram 1202 is always set to 0.

[0083] LMB set 1204 carries the LMBs for each bit set to 1 in LMB presence bitmap 1202 in the same order as in LMB presence bitmap 1202. In this case, each LMB includes three bits corresponding to three different links (link 1, link 2, link 3), so LMB set 1204 has a total size of 6 bits. Bits in the LMB corresponding to MLD are set to 1 to indicate that the BU is available in the corresponding link. In this case, the first LMB in LMB set 1204 corresponding to MLD 2 has the second and third bits set to 1, indicating that the BU of MLD 2 is available in links 2 and 3. In this example, the total overhead of the link / TID / AC information using LMB presence bitmap 1202 (5 bits) and LMB set 1204 (6 bits) is 11 bits.

[0084] In another embodiment, the existence bitmap 1004 may be a Link Recommendation (LR) existence bitmap, and the link / TID / AC information set 1006 is an LR bitmap set. For the default TID-to-link mapping, where TIDs are mapped to all enabled links, the LR existence bitmap indicates whether the corresponding LR bitmap exists in the LR bitmap set. If the link sending the TIM / beacon frame carrying the TIM element is recommended, or if the AP MLD does not recommend a link, the bit corresponding to the MLD is set to 0; and if a link other than the current link is recommended, it is set to 1.

[0085] The LR Presence Bitmap carries bits for each bit set to 1 in the TIM Bitmap in the same order as the LR Presence Bitmap, and the LR Bitmap Set carries the LR Bitmap for each bit set to 1 in the LR Presence Bitmap in the same order as the LR Presence Bitmap. Unlike the LMB, the current link is excluded from the LR Bitmap because the current link can be recommended by setting the corresponding bit in the LR Presence Bitmap to 0. Advantageously, bits set to 0 in the LR Presence Bitmap indicate that the corresponding non-AP MLD only needs to be retrieved in the current link, and the LR Bitmap Set does not require the LR Bitmap, reducing the overhead of link / TID / AC information.

[0086] Figure 13 Example TIM bitmap 1300, example LR presence bitmap 1302, and example LR bitmap set 1304 from TIM / beacon frames are depicted. In TIM bitmap 1300, the TIM bits corresponding to AIDs 12, 28, 35, 57, and 77, respectively, assigned to MLD 1, MLD 2, Legacy 1, MLD 3, and Single Link MLD 4, are set to 1, indicating that the AP MLD has one or more buffered frames to send to those STA / MLDs. LR presence bitmap 1302 carries the bits for each bit set to 1 in the same order as in TIM bitmap 1300, thus LR presence bitmap 1302 has a total size of 5 bits.

[0087] In this example, the AP MLD sending the TIM / beacon frame operates on three links (link 1, link 2, and link 3), and the TIM / beacon frame is sent on link 1 (here referred to as the current link). MLD 1 only has a BU mapped to the TID of link 1, while MLD 4 operates only on link 1. Since the BUs for the TIDs of MLD 1 and MLD 4 are mapped to the current link (link 1), no additional information is needed for MLD 1 and MLD 4, and the LR bitmap in LR bitmap set 1304 exists or is needed only for MLD 2 and MLD 3. The first and fifth bits corresponding to MLD 1 and MLD 4 in LR presence bitmap 1302 are set to 0, indicating that the BU is available only on the current link (link 1); while the second and fourth bits corresponding to MLD 2 and MLD 3 in LR presence bitmap 1302 are set to 1 to indicate that their BUs are also available on another link (link 2, link 3). Traditional 1 is a traditional STA, therefore the third bit corresponding to traditional 1 in the LR bit map 1302 is always set to 0.

[0088] LR bitmap 1304 carries the LR for each bit set to 1 in LR presence bitmap 1202 in the same order as in LR presence bitmap 1202. In this case, each LR bitmap includes two bits corresponding to two different links (link 2, link 3) other than the current link (link 1), so LR bitmap 1304 has a total size of 4 bits. The bits in the LR bitmap corresponding to MLD are set to 1 to indicate that BU is recommended in the links other than the current link. In this case, the first LR bitmap of LR bitmap 1304 is associated with MLD 2, and its first bit is set to 1, indicating that MLD 2 recommends link 2, and the second LR bitmap of LR bitmap 1304 is associated with MLD 3, and its second bit is set to 1, indicating that MLD 3 recommends link 3. The total overhead of the link / TID / AC information using LR presence bitmap 1302 (5 bits) and LR set 1304 (4 bits) is 9 bits.

[0089] In addition to using the LR Presence Bitmap and LR Bitmap Set in the default TID-to-link mapping, when different TIDs are mapped to different link sets, one or more of the enabled links can be classified into the link set, and they can also be used. In this case, the Presence Bitmap can be the Link Set Presence Bitmap, and the Link / TID / AC Information Set is the Link Set Bitmap Set. The Link Set Presence Bitmap indicates whether the corresponding Link Set Bitmap exists in the Link Set Bitmap Set. If the link sending the TIM / Beacon frame carrying the TIM element is the only link in the link set, and there is only a BU for that link set, then the bit corresponding to the MLD is set to 0; and if there is a BU for other link sets, then it is set to 1.

[0090] The link set existence bitmap carries bits set to 1 for each bit in the TIM bitmap in the same order as the link set existence bitmap, and the link set bitmap carries the link set bitmap for each bit set to 1 in the link set existence bitmap in the same order as the link set existence bitmap. The LR bitmap set can also be used for bits set to 1 in the link set bitmap set to indicate which link in the link set the BU exists on.

[0091] Figure 14Example TIM bitmap 1400, example link set presence bitmap 1402, example link set bitmap 1404, and LR bitmap 1406 are depicted. In TIM bitmap 1400, the TIM bits corresponding to AIDs 12, 28, 35, 57, and 77, respectively assigned to MLD 1, MLD 2, Legacy 1, MLD 3, and Single Link MLD 4, are set to 1, indicating that the AP MLD has one or more buffered frames to send to those STAs / MLDs. Link set presence bitmap 1402 carries the bits for each bit set to 1 in the same order as in TIM bitmap 1400, thus link set presence bitmap 1402 has a total size of 5 bits.

[0092] In this example, the AP MLD sending the TIM / beacon frame operates on three links (link 1, link 2, and link 3), and the TIM / beacon frame is sent on link 3 (here referred to as the current link or current link set). TIDs 0-3 are mapped to links 1 and 2, so links 1 and 2 can be classified into link set (link set 1), and TIDs 4-7 are mapped to link 3, which is classified into another link set (link set 2). MLD 1 and MLD 2 only have BUs mapped to TIDs of link set 2 (i.e., link 3), while MLD 4 operates only on link 3. Since the BUs for the TIDs of MLD 1, MLD 2, and MLD 4 are mapped to the current link set (link set 2 or link set 3), no additional information is needed for MLD 1, MLD 2, and MLD 4, and the link set bitmap in link set bitmap set 1404 exists or is needed only for MLD 3. In Link Set Existence Bitmap 1402, the first, second, and fifth bits corresponding to MLD 1, MLD 2, and MLD 4 are set to 0 to indicate that the BU is only available on the current link set; while the fourth bit corresponding to MLD 3 is set to 1 to indicate that the BU is also available on another link set (Link Set 1). Classic 1 is a Classic STA, therefore the third bit corresponding to Classic 1 in Link Set Existence Bitmap 1402 is always set to 0.

[0093] Link set bitmap 1404 carries the link set bitmap for each bit set to 1 in the same order as in link set existence bitmap 1402. In this case, each link set bitmap includes two bits corresponding to two different link sets (link set 1, link set 2), so link set bitmap 1404 (containing only one link set bitmap) has a total size of 2 bits. Bits in the link set bitmap corresponding to MLDs are set to 1 to indicate that a BU exists in that link set. In this case, the first bit in the link set bitmap associated with MLD 3 is set to 1, indicating that the BU for MLD 3 exists in link set 1. LR bitmap 1406 carries the LR bitmap for each bit set to 1 in link set bitmap 1404. Bits in the LR bitmap corresponding to links in the link set indicate that the BU is in that link of the link set. In this case, the LR bitmap associated with MLD 3 in LR bitmap 1406 sets its first bit to 1, indicating the presence of a BU in link 1 of link set 1. The total overhead for the link / TID / AC information using link set presence bitmap 1402 (5 bits), link set bitmap 1404 (4 bits), and LR bitmap 1406 (2 bits) is 9 bits.

[0094] In one embodiment, such as Figure 10 The existence bitmap 1004 shown can be a TID information existence bitmap, and the link / TID / AC information set 1006 is a TID information bitmap set, wherein the LR existence bitmap indicates whether the corresponding TID information exists in the TID information bitmap set. If the buffer BU belongs only to the TID of the link that sends the TIM / beacon frame carrying the TIM element, the bit corresponding to the MLD is set to 0; and if the BU of the TID mapped to other links is also buffered, it is set to 1.

[0095] The TID information bitmap carries bits set to 1 for each bit in the TIM bitmap in the same order as the TID information bitmap, and the TID information bitmap set carries the TID information bitmap for each bit set to 1 in the TID information bitmap in the same order as the TID information bitmap. Advantageously, when the bits for non-AP MLDs are set to 0 in the TID information bitmap, the non-AP MLD only needs to retrieve the BU in the current link, and the TID information bitmap set does not require the TID information bitmap, thus reducing the overhead of link / TID / AC information.

[0096] Figure 15Example TIM bitmap 1500, TID information presence bitmap 1502, and TID information bitmap set 1506 from a TIM / beacon frame are depicted. In TIM bitmap 1500, the TIM bits corresponding to AIDs 12, 28, 35, 57, and 77, respectively assigned to MLD 1, MLD 2, Traditional 1, MLD 3, and Single Link MLD 4, are set to 1, indicating that the AP MLD has one or more buffered frames to send to those STAs / MLDs. TID information presence bitmap 1502 carries the bits for each bit set to 1 in the same order as in TIM bitmap 1500, thus the TID information presence bitmap has a total size of 5 bits.

[0097] In this example, the AP MLD that sends TIM / beacon frames operates on three links (link 1, link 2, and link 3), and the TIM / beacon frames are sent on link 1 (here referred to as the current link). MLD 1 only has a BU mapped to the TID on link 1, while MLD 4 operates only on link 1. Since the BUs for the TIDs of MLD 1 and MLD 4 are mapped to the current link, no additional information is needed for MLD 1 and MLD 4, and the TID information bitmap in TID information bitmap set 1504 exists or is needed only for MLD 2 and MLD 3. In the TID information bitmap 1502, the first and fifth bits corresponding to MLD 1 and MLD 4 are set to 0 to indicate that the buffer BUs for MLD 1 and MLD 4 belong only to TIDs mapped to the current link (link 1). The second and fourth bits corresponding to MLD 2 and MLD 3 are set to 1 to indicate that the BUs for TIDs mapped to other links (link 2 and link 3) are also buffered. Traditional 1 is a traditional STA, therefore the third bit corresponding to Traditional 1 in the TID information bitmap is always set to 0.

[0098] TID information bitmap 1504 carries the TID information bitmap for each bit set to 1 in TID information presence bitmap 1502 in the same order as in TID information presence bitmap 1502. In this case, each TID information bitmap includes eight bits corresponding to eight TIDs (TID 0-7), so TID information bitmap 1504 has a total size of 16 bits. If the BU of TIDs mapped to other links (link 2, link 3) is also buffered, the bits corresponding to MLDs in the TID information bitmap are set to 1. In this case, the TID information bitmap of TID information bitmap 1504 is associated with MLD2, and its second to seventh bits (corresponding to TIDs 1-6) are set to 1, indicating that the BUs of TIDs 1-6 mapped to other links are also buffered. In this case, the total overhead of link / TID / AC information using TID information presence bitmap 1502 (5 bits) and TID information bitmap 1504 (16 bits) is 21 bits.

[0099] Instead, instead of the TID information bitmap (8 bits), a single TID (3 bits) can be... Figure 7 A similar signaling method is used as described in the diagram, but only for the bits of MLDs that are set to 1 in the TID information bit map 1502 (in this case, for MLD 2 and MLD 3).

[0100] Furthermore, in one embodiment, the TID-to-link mapping is performed per access class (AC), meaning that the two TIDs of an AC are always mapped to a link together, and they are never mapped to a link individually. In such an embodiment, the presence bitmap can be an AC information presence bitmap, and the link / TID / AC information set is an AC information bitmap set, wherein the AC information presence bitmap indicates whether the corresponding AC information exists in the AC information bitmap set. If the BU of the TID of an AC mapped to the link that sends a TIM / beacon frame carrying TIM elements (here referred to as the current link) is buffered, the bit corresponding to the MLD is set to 0; and if the BU of the TID of an AC mapped to other links is also buffered, it is set to 1. Advantageously, when the bit in the AC information presence bitmap for non-AP MLDs is set to 0, the non-AP MLD only needs to retrieve the BU in the current link.

[0101] The AC information presence bitmap carries bits for each bit set to 1 in the TIM bitmap in the same order as the AC information presence bitmap, and the AC information bitmap set carries the AC information bitmap for each bit set to 1 in the AC information presence bitmap in the same order as the AC information presence bitmap. Advantageously, bits for non-AP MLDs in the AC information presence bitmap are set to 0, since non-AP MLDs only need to retrieve the BU in the current link, and the AC information bitmap set does not require the AC information bitmap, thus reducing the overhead of link / TID / AC information.

[0102] Figure 16 Example TIM bitmap 1600, example AC information presence bitmap 1602, and example AC information bitmap set 1604 from TIM / beacon frames are depicted. In TIM bitmap 1600, the TIM bits corresponding to AIDs 12, 28, 35, 57, and 77, respectively assigned to MLD 1, MLD 2, Traditional 1, MLD 3, and Single Link MLD 4, are set to 1, indicating that the AP MLD has one or more buffered frames to send to those STAs / MLDs. AC information presence bitmap 1602 carries bits for each bit set to 1 in the same order as in TIM bitmap 1600, thus TIM information presence bitmap 1602 has a total size of 5 bits.

[0103] In this example, the AP MLD sending TIM / beacon frames operates on three links (link 1, link 2, and link 3). TIM / beacon frames are sent on link 1 (referred to here as the current link). There are four ACs: AC_BK, AC_BE, AC_VI, and AC_VO. Two TIDs are mapped to each of the four ACs. Example AC-TID mappings are shown in Table 1 below. The two TIDs for each AC are always mapped to a link. In this example, AC_VO and AC_VI are mapped to links 1 and 2; while AC_BE and AC_BK are mapped to link 3.

[0104] MLD 1 only has a BU mapped to the AC on link 1, while MLD 4 operates only on link 1. Since the BUs for the ACs used in MLD 1 and MLD 4 are mapped to the current link, no additional information is needed for MLD 1 and MLD 4, and the AC information bitmap in AC information bitmap set 1604 exists or is needed only for MLD 2 and MLD 3. The first and fifth bits corresponding to MLD 1 and MLD 4 in AC information bitmap 1602 are set to 0 to indicate that the BUs of the TIDs of the ACs mapped only to the current link (link 1) are buffered; while the second and fourth bits corresponding to MLD 2 and MLD 3 in AC information bitmap 1602 are set to 1 to indicate that the BUs of their ACs mapped to other links (link 2 and link 3) are also buffered. Classic 1 is a Classic STA, therefore the third bit corresponding to Classic 1 in AC information bitmap 1602 is always set to 0.

[0105] Table 1. An example AC-TID mapping

[0106]

[0107] AC information bitmap 1604 carries the AC information bitmap for each bit set to 1 in AC information presence bitmap 1602 in the same order as in AC information presence bitmap 1602. In this case, each AC information bitmap includes four bits corresponding to the four ACs (AC_BK, AC_BE, AC_VI, AC_VO), thus AC information bitmap 1604 has a total size of 8 bits. In this case, the total overhead for link / TID / AC information using AC information presence bitmap 1602 (5 bits) and AC information bitmap 1604 (4 bits) is 13 bits.

[0108] According to this disclosure, different portions of the TIM bitmap (e.g., the AID space) can be reserved for assigning AIDs to traditional STA / non-MLD ultra-high throughput (EHT) STA and non-AP MLD, wherein the different portions do not overlap.

[0109] Figure 17 Example AID allocation and three example TIM bitmaps 1700, 1710, and 1720, respectively, sent from the AP MLD on three links, are depicted. In this example, the AP MLD uses 255 consecutive AIDs (out of a maximum of 2007), and the first AID (0) is used to indicate a group-addressed frame and is not assigned to a STA; the next 30 AIDs (1-30) are reserved for traditional STAs and single-link EHT STAs, and the remaining AIDs (31-255) are used for non-AP MLDs.

[0110] Each TIM bit is mapped to an AID. Therefore, after the first TIM bit associated with AID 0, the latter part of the TIM bitmap (in this case, the part associated with AIDs 1-30) is reserved for traditional STAs and non-MLD EHTSTAs (here referred to as the AID space for non-MLD STAs), and the remaining part of the TIM bitmap is used for non-AP MLDs (here referred to as the AID space for non-AP MLDs). Advantageously, this AID allocation also reduces the overhead of link / TID / AC information.

[0111] Thus, through AID allocation, the link / AID / AC information associated with the buffer BU exists only for non-AP MLDs in the link / AID / AC information set. The starting AID field can be used to indicate the first AID (e.g., the smallest AID) of the non-AP MLD whose link / AID / AC information is included in the AID space of the non-AP MLDs in the link / TID / AC information set. (See the appendix below.) Figure 19 and Figure 21 In the description, various embodiments of this disclosure are based on example AID allocation for example TIM bitmap 1710.

[0112] Figure 18 Example beacon / TIM frame 1800 is depicted. Although the format of the beacon / TIM frame is shown, it will be understood that the same format can be applied to Fast Initial Link Establishment (FILS) discovery frames or Operation (OPS) frames. Beacon / TIM frame 1800 carries TIM element 1802 including a partial virtual bitmap (PVM) 1808, a start AID field 1804, and a link / TID / AC information set 1806 including link / RID / AC information for each associated MLD.

[0113] Figure 19 TIM bitmap 1900 and example LMB set 1904 in beacon / TIM frames are depicted. In TIM bitmap 1900, the TIM bit is set to 1 if the AP MLD has a buffered frame to send to a non-AP STA / MLD on any link to be used. The TIM bits corresponding to AIDs 11, 12, 35, 57, 77, and 255, respectively, assigned to legacy 2, single-link EHT STA, MLD 1, MLD 2, MLD 3, and single-link MLD 4, are set to 1, indicating that the AP MLD has one or more buffered frames to send to those STAs / MLDs.

[0114] The Start AID field 1902 indicates the minimum AID assigned to a non-AP MLD with the TIM bit set to 1, meaning that link / TID / AC information exists in the frame. In this case, the Start AID is 35. By allocating the non-AP MLD AID space and the Start AID in the TIM bitmap, the bitmap may not need to exist, thus reducing the overhead of link / TID / AC information.

[0115] Based on the starting AID in the starting AID field 1902 and the TIM bitmap 1900, non-AP MLDs can determine the position of their corresponding link / TID / AC information in the link / TID / AC information set. Specifically, starting AID 35 indicates that the first entry in the link / TID / AC information set is associated with the non-AP MLD assigned to AID 35, which in this case is MLD 1.

[0116] Figure 20 Another example beacon / TIM frame 2000 is depicted. The link / TID / AC information presence bitmap 2005 can be used in conjunction with the start AID field 2004 to further reduce the overhead of the link / TID / AC information.

[0117] Figure 21 Example TIM bitmap 2100, example TID information presence bitmap 2104, and example TID information bitmap set 2106 in beacon / TIM frames are depicted. In TIM bitmap 2100, the TIM bits corresponding to AIDs 11, 12, 35, 57, 77, and 255, respectively assigned to legacy 2, single-link EHTSTA, MLD 1, MLD 2, MLD 3, and single-link MLD 4, are set to 1, indicating that the AP MLD has one or more buffered frames to send to those STAs / MLDs. In this example, the TIM is sent in link 2, and the start AID field 2102 is set to the beginning of the AID space for non-AP MLDs (AID 31). The TID information presence bitmap carries bits set to 1 for the corresponding bits in the TIM bitmap that start with the AID pointed to by the start AID field (i.e., 31). By allocating non-AP MLD AID space and starting AID 2102 in TIM bitmap 2100, the TID information presence bitmap 2104 for the AID space (AID 1-30) for non-MLD STAs is omitted, thus reducing the overhead of link / TID / AC information.

[0118] In this example, MLD 1 only has a buffer BU mapped to link 2, while MLD 4 operates only on link 1; therefore, the TID information for MLD 4 is not included in link 2. No additional information for buffered BUs for MLD 1 and MLD 4 is required, and the TID information bitmap in TID information bitmap set 2106 exists or is required only for MLD 2 and MLD 3. The second and third bits corresponding to MLD 2 and MLD 3 in the TID information bitmap 2104 are set to 1 to indicate that their BUs mapped to other links are also buffered.

[0119] The TID information bitmap set carries the TID information bitmap for each bit set to 1 in the same order as in the TID information presence bitmap 2104. In this case, a single TID (3 bits) is signaled for each of MLD 2 and MLD 3, so the TID information bitmap set 2106 has a total size of 6 bits. The 3-bit TIDs 101 and 111 signal the BUs for TIDs 5 and 7, which are buffered for MLD 2 and MLD 3, respectively. If there is a BU for other TIDs, they are signaled in the A-control field of the subsequent data frame belonging to the indicated TID.

[0120] In an embodiment, for an AP that is a member of a multi-BSSID set (i.e., a virtual AP), bits 1 to (2^n-1) of the TIM bitmap are used to indicate that one or more group addressing frames are buffered for each AP (virtual AP) corresponding to an unsent BSSID, and are referred to as the NonTxBSS identifier (NonTxBSSID). These bits are not assigned to STAs in the BSS. Furthermore, some AIDs may also be reserved to signal the presence of the group addressing BU to other APs belonging to the AP MLD, and these AIDs may appear immediately after the AIDs assigned to the virtual AP, if present. The AP MLD can also reduce the overhead of link / TID / AC information for traditional STAs by appropriately planning their AID space for associated non-AP STAs / MLDs. For example, the AP MLD may assign AIDs to associated non-AP MLDs from the AID space immediately following the last AID (e.g., 3) reserved for the AP, and to associated non-MLD STAs from the AID space following the AID space reserved for the non-AP MLD.

[0121] Figure 22Example TIM bitmap 2200, AC information presence bitmap 2202, and AC information bitmap set 2204 sent from AP MLD in a link are depicted. In this example, AP MLD uses 255 consecutive AIDs (maximum of 2008), and the first 4 AIDs (0-3) are used to indicate group addressing frames corresponding to 4 virtual APs; the following 200 AIDs (4-203) are reserved for non-AP MLDs operating on multiple links, and the remaining AIDs (204-255) are used for traditional STAs and single-link EHT STAs.

[0122] Each TIM bit is mapped to an AID. Therefore, the beginning portion 2211 of the TIM bitmap 2202 (in this case, the TIM bits associated with AID 0-3) is reserved for AP MLD (here referred to as the AID space of AP MLD). After the AID space 2211 of AP MLD, the later portion 2212 of the TIM bitmap (in this case, the portion associated with AID 11-203) is reserved for non-AP MLD (here referred to as the AID space of non-AP MLD), and the remaining portion 2213 of the TIM bitmap is reserved for traditional STA and non-MLD EHT STA (here referred to as the AID space of non-MLD STA).

[0123] The AID space 2212 of the non-AP MLD immediately begins (appended to) the AID space 2211 reserved for the AP in the TIM bitmap 2200. Single-link MLDs (e.g., Figure 22 The single-link MLD 4) in the AP can also be assigned an AID from the AID space of the non-MLD STA, such that the AID space 2212 of the non-AP MLD is specifically reserved for non-AP MLDs operating on multiple links. Instead of having a fixed AID space, the AID space boundaries may not be clearly defined. For example, non-AP MLDs operating on multiple links are assigned AIDs consecutively starting from the first available AID (e.g., 4, 5, 6, ... etc.), while conventional STAs and single-link EHT STAs are assigned AIDs consecutively from the last AID in the AP's AID space (e.g., 255, 254, 253, ... etc.). Advantageously, since the AID space reserved for the AP (e.g., non-NonTxBSS IDs) is known to all associated STAs, the starting AID is known and can be omitted in this scheme.

[0124] Back Figure 22Through AID allocation, the link / AID / AC information associated with the buffered BU exists only for non-AP MLDs, while traditional STAs and non-MLD EHT STAs are not included in the link / AID / AC information set. Therefore, the existence of the bitmap only requires bits for non-AP MLDs. The TIM bits corresponding to AIDs 12, 28, 35, 56, 204, 227, and 225, respectively, assigned to MLD 1, MLD 2, MLD 3, single-link MLD 4, MLD 1, MLD 2, MLD 3, and single-link MLD 4, are set to 1, indicating that the AP MLD has one or more buffered frames to send to those STAs / MLDs. In this example, the TIM is sent on link 3. MLD 1 only has BUs with TIDs mapped to link 3, while MLD 4 only operates on link 1, therefore AC information for MLD 4 is not included. Additional information for the buffered BUs of MLD1 and MLD4 is not required, and the AC information bitmap in AC information bitmap set 2204 exists or is required only for MLD2 and MLD3. The second and third bits of the TID information in bitmap 2202 corresponding to MLD2 and MLD3 are set to 1 to indicate that the BUs of ACs mapped to other links are also buffered.

[0125] AC information bitmap set 2204 carries each AC information bitmap set to 1 in the same order as in AC information presence bitmap 2202. In this case, each AC information bitmap includes four bits corresponding to the four ACs (AC_BK, AC_BE, AC_VI, AC_VO), thus AC information bitmap set 2204 has a total size of 8 bits. The total overhead for link / TID / AC information using the AC information presence bitmap (3 bits) and AC information bitmap set (8 bits) is 11 bits.

[0126] In another embodiment, even without any restrictions on AID allocation, an indication of the starting AID (e.g., using a starting AID field) can be used to help reduce the overhead of link / TID / AC information by excluding STAs with AIDs less than the starting AID. Excluded STAs can be traditional STAs, non-MLD EHT STAs, or even MLDs that do not have link / TID / AC information.

[0127] Figure 23Example TIM bitmap 2300, example TID information presence bitmap 2304, and example TID information bitmap set 2306 are depicted in beacon / TIM frames. TIM bits corresponding to AIDs 11, 12, 35, 57, 77, and 255, respectively assigned to Traditional 2, Single-Link EHT STA, MLD 1, Traditional 7, MLD 3, and Single-Link MLD 4, are set to 1, indicating that the AP MLD has one or more buffered frames to send to those STAs / MLDs. Without any restrictions on AID allocation, the AIDs of Traditional STAs (e.g., Traditional 7) and non-AP MLDs may be mixed. The Start AID field 2302 can indicate the AID of the first non-AP MLD (i.e., the smallest AID associated with the non-AP MLD), for which link / TID / AC information is included in the link / TID / AC information set. In this case, the Start AID field 2302 indicates a Start AID of 35. This helps to exclude Traditional 2 and Traditional 3 from the TID information bitmap set. Traditional STAs and non-MLD EHT STAs are still included in the link / TID / AC information set, but only those STAs with an AID higher than the starting AID are included (e.g., traditional 7).

[0128] TID information presence bitmap 2304 carries bits for each bit set to 1 in the TIM bitmap in the same order as in TIM bitmap 2300, thus TID information presence bitmap 2304 has a total size of 4 bits. In this case, the first and third bits corresponding to MLD 1 and MLD 3 in TID information presence bitmap 2304 are set to 1. TID information bitmap set 2306 carries TID information bitmaps for each bit set to 1 in TID information presence bitmap 2304 in the same order as in TID information presence bitmap 2304 (in this case, a single TID with 3 bits). In this case, the first and third bits corresponding to MLD 1 and MLD 3 in TID information presence bitmaps are set to 1, thus TID information bitmap set 2306 has a size of 6 bits. In this case, the total overhead of link / TID / AC information using TID information presence bitmap 2304 (4 bits) and TID information bitmap set 2306 (6 bits) is 10 bits.

[0129] Figure 24A sample format for a multi-link TIM element 2400 is described. A multi-link TIM 2400 can be a new element or a multi-link element with a type field set to "Multi-link TIM," defined as carrying an existence bitmap and a set of link / TID / AC information. A multi-link TIM element includes an element field, a length field, an element ID extension field, a multi-link control field including a type field (set to "Multi-link TIM") and an existence bitmap, a common information field, and a link information field.

[0130] The presence bitmap field of the multi-link control field also includes a start AID presence field and a presence bitmap size presence field, which are used to indicate the presence of the start AID field and presence bitmap size field in the common information field. The common information field also includes a link / TID / AC information type field, a start AID field, and a presence bitmap size field. The link information field also includes a link / TID / AC information presence bitmap presence field, a link / TID / AC information presence bitmap, and a link / TID / AC information set field. As shown in Table 2 below, the link / TID / AC information type field indicates what type of information is carried in the link / TID / AC information set field. The presence bitmap size field indicates the size of the link / TID / AC information presence bitmap.

[0131] The Link / TID / AC information bitmap field indicates whether further information about the buffer BU exists in the Link / TID / AC information and is set for non-AP MLDs. The Link / TID / AC information set field carries further information about the buffer BU used for each non-AP MLD.

[0132] According to this disclosure, assuming that different AID spaces are reserved for assigning AIDs to traditional STAs (11n, 11ac, 11ax STAs) and EHT devices (non-MLD EHT non-AP STAs and non-AP MLDs), then a separate TIM element (e.g., an existing baseline TIM element) can be specifically used to signal buffer BUs for traditional STAs, while a new multi-link TIM bitmap is included in the multi-link TIM element to signal buffer BUs dedicated to EHT devices. AIDs used to indicate group address BUs (e.g., AID 0, NonTxBSS ID, or AID space for AP MLDs) are duplicated in both the TIM bitmaps of traditional STAs and the multi-link TIM bitmaps of EHT devices.

[0133] Table 2. Values ​​in the Link / TID / AC Information Type field and their corresponding information types

[0134]

[0135] Figure 25 Example TIM bitmap 2500 and example multi-link TIM bitmap 2510, example AC information presence bitmap, and example AC information bitmap set are depicted in the beacon / TIM frame. In this example, the AP MLD uses 1020 consecutive AIDs (out of a maximum of 2008). 510 consecutive AIDs (1-510) are reserved for legacy STAs, and the remaining AIDs (511-1020) are used for EHT devices. Therefore, TIM bitmap 2500 is used to indicate buffer BUs dedicated to legacy devices, in which case legacy 1 and legacy 2 are assigned to AIDs 34 and 76, respectively, and multi-link TIM bitmap 2510 is used to indicate buffer BUs dedicated to EHT devices, such as MLD 1, MLD 2, non-MLD EHT STA 1, MLD 3, and single-link MLD 4, assigned to AIDs 51, 528, 535, 557, and 577, respectively. The AID used to indicate the group address BU, in this case, AID 0 is copied in the multi-link TIM bitmap, as indicated by 2505.

[0136] A traditional STA only needs to decode the TIM bitmap 2500; while an EHT STA only needs to decode the multilink TIM bitmap 2510. The bits in the multilink bitmap immediately following the duplicate bits 2505 used to indicate group / broadcast addressing frames correspond to the first AID in the AID space reserved for EHT devices. To avoid bit duplication in the TIM bitmap, different AID spaces can be reserved for assigning AIDs to traditional STAs and EHT devices.

[0137] As a variant, all non-MLD STAs can also be assigned AIDs from the AID space of traditional STAs, and the baseline TIM can be used to indicate the buffer BU for non-MLD STAs. Non-MLD STAs refer to traditional STAs as well as EHT STAs that are not part of MLD.

[0138] As a further variation, a single-link MLD can also be assigned an AID from the AID space of a legacy STA, so that the legacy STA's AID space is reserved specifically for legacy STAs and all EHT devices operating on a single link, and the baseline TIM can also be used to indicate the buffer BU for the single-link MLD. In this case, the multi-link TIM bitmap is specifically used to indicate the buffer BU used only for non-AP MLDs.

[0139] AC information presence bitmap 2502 carries bits for each bit set to 1 in the multi-link TIM bitmap 2510 in the same order as in the multi-link TIM bitmap 2510, thus AC information presence bitmap 2502 has a total size of 5 bits. AC information bitmap set 2504 carries AC information bitmaps for each bit set to 1 in the AC information presence bitmap 2502 in the same order as in AC information presence bitmap 2502. Each AC information bitmap includes 4 bits corresponding to four ACs. In this case, the first and fourth bits corresponding to MLD 2 and MLD 3 in AC information presence bitmap 2502 are set to 1, thus AC information bitmap set has a size of 8 bits. In this case, the total overhead of link / TID / AC information using separate TIM elements for EHT devices, AC information presence bitmap 2502 (5 bits), and AC information bitmap set 2504 (8 bits) is 13 bits.

[0140] Figure 26 A sample format for a multi-link TIM element 2600, including a multi-link TIM bitmap, is described. The multi-link TIM 2600 includes an element field, a length field, an element ID extension field, a type field (including a type field set to "multi-link TIM"), a multi-link control field containing a bitmap field, a common information field, and a link information field.

[0141] The presence bitmap field of the multi-link control field also includes a start AID presence field, a multi-link TIM information presence field, and a presence bitmap size presence field. These are used to indicate the presence of the start AID field, multi-link TIM information field, and presence bitmap size field in the common information fields. The common information fields also include a link / TID / AC information type field, a start AID field, a multi-link TIM information field, and a presence bitmap size field. The link information fields also include a link / TID / AC information presence bitmap presence field, a link / TID / AC information presence bitmap field, and a link / TID / AC information set field. The multi-link TIM information fields also include a bitmap control field, a bitmap length field, and a multi-link TIM bitmap field. The bitmap control field has similar characteristics to... Figure 24The bitmap control fields described and shown have the same function as those in the conventional TIM elements. The bitmap length field indicates the length of the multi-link bitmap in octets. The multi-link TIM bitmap field indicates a buffer BU dedicated to an EHT device or a non-AP MLD. The link / TID / AC information type field indicates what type of information is carried in the link / TID / AC information set field, similar to what is shown in Table 2 above. The link / TID / AC information presence bitmap field indicates whether further information about the buffer BU is present in the link / TID / AC information and is set for non-AP MLDs. The link / TID / AC information set field carries further information about the buffer BU used for each non-AP MLD.

[0142] Figure 27 An example configuration of communication device 2700 and three communication devices 2712, 2722, and 2732 belonging to communication device 2700 is shown. According to various embodiments of this disclosure, communication device 2700 is implemented as an AP MLD, and each of the belonging communication devices 2712, 2722, and 2732 can be implemented as an AP configured for a multi-link service indication map. Communication device 2700 includes a multi-TIM element generator 2702 that performs a multi-link service indication map according to the above embodiments, such as generating multi-link TIM elements and an presence bitmap with a start AID field. The multi-link TIM elements include a partially virtual bitmap (PVM) indicating the presence of one or more buffer units of an external communication device / equipment associated with the communication device. The presence bitmap indicates the presence of additional information (e.g., link / TID / AC information) associated with one or more BUs in the associated external communication device / equipment.

[0143] Communication device 2700 includes a storage module storing its MLD MAC MLD address 2701. Communication device 2700 also includes a MAC SAP 2740 for communicating with the Internet layer and / or the DS. Each communication device 2712, 2722, 2732 belonging to the communication device provides links 2718, 2728, 2738 associated with other external communication devices / equipment and / or the DS, and is capable of sending (e.g., sending frames including multi-link TIM elements and presence bitmaps with fields associated with the start AID) or receiving other signals from other external communication devices / equipment and / or the DS. Each subordinate communication device 2712, 2722, 2732 includes MAC layers 2714, 2724, 2734 and PHY (physical) layers 2716, 2726, 2736. The PHY layer is connected to a radio transmitter, radio receiver, and antenna for sending / receiving signals to / from other communication devices / equipment via corresponding links 2718, 2728, 2738. In an embodiment, the MAC layer includes a storage module storing its AP MAC addresses 2715, 2725, 2735 and optional AP MACSAP for direct communication with the Internet layer for traffic to / from legacy STAs.

[0144] Figure 28 An example configuration of communication device 2800 and three communication devices 2812, 2822, and 2832 belonging to communication device 2800 is shown. According to various embodiments of this disclosure, communication device 2800 is implemented as a non-AP MLD, and each of the belonging communication devices 2812, 2822, and 2832 may be implemented as a STA configured for a multi-link service indication map. Communication device 2800 also includes a multi-TIM element parser 2802, which performs a multi-link service indication map according to the above embodiments, such as receiving and processing multi-link TIM elements and an presence bitmap with a start AID field. The multi-link TIM elements include a partially virtual bitmap (PVM) indicating the presence of one or more buffer units of communication device 2800. The presence bitmap indicates whether additional information (e.g., link / TID / AC information) associated with one or more BUs is present for communication device 2800.

[0145] Communication device 2800 includes a storage module storing its MLD MAC MLD address 2801. Communication device 2800 also includes a MAC SAP 2840 for communicating with the Internet layer and / or the DS. Each of the communication devices 2812, 2822, and 2832 belonging to the communication device provides links 2818, 2828, and 2838 for association with other external communication devices / equipment and / or the DS and is capable of receiving / transmitting other signals from them. Each belonging communication device 2812, 2822, and 2832 includes MAC layers 2814, 2824, and 2834 and PHY (physical) layers 2816, 2826, and 2836, the PHY layers being connected to a radio transmitter, radio receiver, and antenna for sending / receiving signals to / from other communication devices / equipment via the corresponding links 2818, 2828, and 2838. In this embodiment, the MAC layer includes a storage module that stores its STA MAC addresses 2815, 2825, and 2835, and an optional STA MAC SAP for direct communication with the Internet layer for use with traffic to / from legacy APs / STAs.

[0146] This disclosure can be implemented through software, hardware, or a combination of software and hardware. Each functional block used in the description of each of the above embodiments can be implemented partially or entirely by an LSI, such as an integrated circuit, and each process described in each embodiment can be controlled partially or entirely by the same LSI or a combination of LSIs. An LSI can be formed as a single chip, or a chip can be formed to include some or all of the functional blocks. An LSI may include data inputs and outputs coupled thereto. Depending on the level of integration, the LSI herein may be referred to as an IC, a system LSI, a super LSI, or an ultra-LSI. However, the technology for implementing integrated circuits is not limited to LSIs and can be implemented using dedicated circuits, general-purpose processors, or special-purpose processors. Furthermore, FPGAs (Field-Programmable Gate Arrays) that can be programmed after the LSI is manufactured, or reconfigurable processors in which the connections and settings of circuit cells arranged within the LSI can be reconfigured, can be used. This disclosure can be implemented as digital or analog processing. If future integrated circuit technologies replace LSIs due to advancements in semiconductor technology or other derivative technologies, future integrated circuit technologies can be used to integrate the functional blocks. Biotechnology can also be applied.

[0147] This disclosure can be implemented by any kind of means, apparatus or system with communication capabilities (referred to as a communication device).

[0148] Some non-limiting examples of such communication devices include telephones (e.g., cellular phones, smartphones), tablet computers, personal computers (PCs) (e.g., laptops, desktops, netbooks), cameras (e.g., digital cameras / camcorders), digital players (digital audio / video players), wearable devices (e.g., wearable cameras, smartwatches, tracking devices), game consoles, digital book readers, remote health / telemedicine (remote health and medical) devices, and vehicles that provide communication capabilities (e.g., cars, airplanes, ships) and various combinations thereof.

[0149] Communication devices are not limited to portable or mobile devices, but may also include any kind of non-portable or fixed device, equipment or system, such as smart home devices (e.g., appliances, lighting, smart meters, control panels), vending machines and any other “thing” in an “Internet of Things (IoT)” network.

[0150] Communication may include the exchange of data through, for example, cellular systems, wireless LAN systems, satellite systems, and various combinations thereof.

[0151] The communication device may include devices such as controllers or sensors coupled to a communication device performing the communication functions described in this disclosure. For example, the communication device may include a controller or sensor that generates control signals or data signals used by the communication device performing the communication functions of the communication device.

[0152] Communication equipment may also include infrastructure such as base stations, access points, and any other means, devices, or systems that communicate with or control such devices as those in the non-limiting examples above.

[0153] A non-limiting example of a station may be a station included in a first plurality of stations belonging to a multi-link station logical entity (i.e., such as an MLD), wherein, as part of the first plurality of stations belonging to the multi-link station logical entity, the stations of the first plurality of stations share a common media access control (MAC) data service interface at the upper layer, wherein the common MAC data service interface is associated with a common MAC address or service identifier (TID).

[0154] Therefore, it can be seen that this embodiment provides communication devices and methods for operation on multiple links in order to fully realize throughput gains in multi-link communication, especially for secure retransmission of multiple links.

[0155] While exemplary embodiments have been presented in the foregoing detailed description of these embodiments, it should be understood that numerous variations exist. It should also be understood that the exemplary embodiments are examples and are not intended to limit the applicability, operation, or configuration of this disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient roadmap for implementing the exemplary embodiments, and it should be understood that various changes can be made to the operational steps and methods described in the exemplary embodiments, as well as the functionality and arrangement of the modules and structures of the device described in the exemplary embodiments, without departing from the scope of the subject matter set forth in the appended claims.

Claims

1. A non-AP MLD that is a non-access point multi-link device (non-AP MLD) including a plurality of stations (STAs), the non-AP MLD comprising: a reception unit that receives a frame including a traffic indication map element (TIM element) and a starting AID field, the TIM element including a partial virtual bitmap (PVM) indicating whether one or more buffer units (BUs) exist for each of a plurality of non-AP MLDs including the non-AP MLD, the starting AID field indicating a smallest AID in which a link information bitmap indicating presence or absence of traffic for each link exists among AIDs corresponding to the plurality of non-AP MLDs; and a circuit that determines a link in which the one or more BUs exist facing itself based on the starting AID field and the link information bitmap.

2. The non-AP MLD according to claim 1, wherein the PVM includes a first portion associated with AIDs assigned to a plurality of legacy STAs and a second portion associated with AIDs assigned to the plurality of non-AP MLDs, a start position of the second portion being specified by a starting AID indicated by the starting AID field.

3. The non-AP MLD according to claim 1, wherein the frame is a beacon frame.

4. The non-AP MLD according to claim 1, wherein a PVM indicating whether one or more BUs exist for each of a plurality of non-AP STAs belonging to each non-AP MLD is included in a TIM element different from the TIM element.

5. A communication method for a non-access point multi-link device (non-AP MLD) including a plurality of stations (STAs), the communication method comprising: a step of receiving a frame including a traffic indication map element (TIM element) and a starting AID field, wherein the TIM element includes a partial virtual bitmap (PVM) indicating whether one or more buffer units (BUs) exist for each of a plurality of non-AP MLDs including the non-AP MLD, the starting AID field indicating a smallest AID in which a link information bitmap indicating presence or absence of traffic for each link exists among AIDs corresponding to the plurality of non-AP MLDs; and a step of determining a link in which the one or more BUs exist facing itself based on the starting AID field and the link information bitmap.

6. The communication method according to claim 5, wherein the PVM includes a first portion associated with AIDs assigned to a plurality of legacy STAs and a second portion associated with AIDs assigned to the plurality of non-AP MLDs, a start position of the second portion being specified by a starting AID indicated by the starting AID field.

7. The communication method according to claim 5, wherein the frame is a beacon frame.

8. The communication method according to claim 5, wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ The PVM indicating whether there is one or more BUs for each of a plurality of non-AP STAs affiliated with the respective non-AP MLD is included in a different TIM element than the TIM element. The PVM indicating whether there is one or more BUs for each of a plurality of non-AP STAs affiliated with the respective non-AP MLD is included in a different TIM element than the TIM

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