Communication apparatus and communication method for multi-link peer-to-peer communication

Abstract

To provide a communication apparatus and a method for multi-link peer-to-peer communication.SOLUTION: A first non-AP MLD having a plurality of attached STAs operating on different links from each other includes a receiving unit that receives a TDLS setup request frame for setting up a direct link connection on one or more links from a second non-AP MLD through an AP or AP MLD, the TDLS setup request frame including a first TDLS multi-link element including first MLD MAC address information indicating the first non-AP MLD, and a transmitting unit that transmits a TDLS setup response frame including information on the one or more links to the second non-AP MLD through the AP or AP MLD if the direct link connection on the one or more links is agreed upon.SELECTED DRAWING: Figure 6A

Description

Technical Field

[0001] Embodiments of the present invention generally relate to communication devices, and more particularly to methods and apparatus for multi-link peer-to-peer communication.

Background Art

[0002] In today's world, communication devices are expected to operate wirelessly with the same capabilities as wired computing devices. For example, a user expects to seamlessly view a high-resolution movie streamed to the user's wireless communication device. This poses challenges not only to the communication device but also to the access points to which the communication device wirelessly connects.

[0003] The Institute of Electrical and Electronics Engineers (IEEE) 802.11 group has recently formed an 802.11 Task Group (TG) to address these challenges. Multi-link operation in the 2.4 GHz, 5 GHz, and 6 GHz frequency bands has been identified as a promising candidate technology for such communication. Multi-channel aggregation across multiple links is a natural way to produce a several-fold increase in communication data throughput.

[0004] To enable such multi-link operation between an access point (AP) multi-link device (MLD) and a non-AP MLD, a multi-link setup can be performed on one of the supported links to establish the association of the affiliated stations (STAs) in one or more links.

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, there has been no discussion so far regarding multi-link peer-to-peer communication between non-AP MLD STAs or between a non-AP MLD and a legacy STA.

[0006] Therefore, there is a need for a communication device and a communication method that can solve the above problems. Further, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the background of this invention of the present disclosure.

Means for Solving the Problems

[0007] Non-limiting and exemplary embodiments facilitate providing a communication device and a communication method for multi-link peer-to-peer communication.

[0008] In a first aspect, the present disclosure provides a communication device among a plurality of communication devices attached to a first multi-link device (MLD), wherein the plurality of communication devices each operate on a corresponding link of the first MLD, and the communication device includes a circuit that generates a request frame during operation, the request frame being one of a discovery request frame for discovering the peer-to-peer communication capability of another communication device or a setup request frame for requesting the setup of one or more direct links, the request frame including a multi-link (ML: multi-link) indication that identifies that the communication device is attached to the first MLD, and a transmitter that transmits the request frame on one link during operation.

[0009] In a second aspect, the present disclosure provides an access point (AP) that is one of a plurality of APs attached to an AP MLD, where the plurality of APs each operate in a corresponding link of the AP MLD, and the AP includes a receiver that, during operation, receives, on one link, a data frame in which a destination address (DA) field is set to another associated communication device not attached to the MLD from an associated communication device attached to the MLD; a circuit that, during operation, sets a source address (SA) field of the data frame as the MAC address of the associated communication device; and a transmitter that, during operation, transmits the data frame to another associated communication device.

[0010] In a third aspect, the present disclosure provides a communication method including generating a request frame, where the request frame is one of a discovery request frame for discovering the peer-to-peer communication capability of a communication device or a setup request frame for requesting setup of one or more direct links, and the request frame includes an ML indication identifying that another communication device transmitting the request frame is attached to the MLD, and transmitting the request frame on one link.

[0011] Further benefits and advantages of the disclosed embodiments will become apparent from the specification and drawings. These benefits and / or advantages can be obtained individually by various embodiments and features of the specification and drawings, provided that not all of these features are required to obtain one or more of such benefits and / or advantages.

[0012] Like reference numerals refer to the same or functionally similar elements throughout the separate figures, and the accompanying drawings, which are incorporated herein and form a part of this specification along with the following detailed description, illustrate various embodiments and are useful for explaining various principles and advantages in accordance with embodiments of the present invention.

Brief Description of the Drawings

[0013]

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DETAILED DESCRIPTION OF THE INVENTION

[0014] Those skilled in the art will recognize that the elements of the 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 assist in an accurate understanding of the embodiments of the present invention.

[0015] The following detailed description is merely exemplary in nature and is not intended to limit the embodiments or the application and uses of the embodiments. Further, there is no intention to be bound by any theory presented in the foregoing background or this detailed description. Further, other desirable features and characteristics will become apparent from the accompanying drawings and the subsequent detailed description and the appended claims of this invention of the present disclosure.

[0016] In the context of IEEE 802.11 (Wi-Fi) technology, a station is interchangeably referred to as an STA and is a communication device having the ability to use the 802.11 protocol. Based on the definition of IEEE 802.11-2016, an STA is any device including an IEEE 802.11-compliant media access control (MAC) and physical layer (PHY) interface to a wireless medium (WM).

[0017] For example, the STA can be a laptop, a desktop personal computer (PC), a personal digital assistant (PDA), an access point, or a Wi-Fi phone in a wireless local area network (WLAN) environment. The STA can be either fixed or mobile. In a WLAN environment, the terms "STA", "wireless client", "user", "user device", and "node" are often used interchangeably.

[0018] Similarly, in the context of IEEE 802.11 (Wi-Fi) technology, the AP can be interchangeably referred to as a wireless access point (WAP), and it is a communication device that enables an STA within a WLAN to connect to a wired network. The AP typically connects to a router as a stand-alone device (via a wired network), but it can also be integrated with or used within a router.

[0019] As described above, an STA within a WLAN can act as an AP on different occasions, and vice versa. This is because in the context of IEEE 802.11 (Wi-Fi) technology, a communication device can include both STA hardware components and AP hardware components. In this way, the communication device can switch between the STA mode and the AP mode based on the actual WLAN conditions and / or requirements.

[0020] In various embodiments of the present disclosure, a multi-link device (MLD) may refer to a device operating in two or more frequency bands or links (2.4 GHz, 5 GHz, or 6 GHz). The MLD may include two or more communication devices corresponding to two or more links that each operate in a specific frequency band or link. For simplicity, each link of the MLD shown in the present disclosure operates in a specific frequency band (2.4 GHz, 5 GHz, or 6 GHz) and is mainly configured to transmit / receive signals with another communication device that does not belong to the MLD and operates in the same specific frequency band. It relates to one of the multiple communication devices attached to the MLD.

[0021] In various embodiments of the present disclosure, a non-MLD STA may refer to a legacy (HE / VHT / HT) STA or EHT STA that does not belong to a non-AP MLD. Similarly, a non-MLD AP may refer to an EHT AP that does not belong to an AP MLD.

[0022] In various embodiments of the present disclosure, the term "L2 MAC address" refers to the MAC address of the transmitting / receiving STA or AP, while the term "MLD MAC address" refers to the MAC address representing the MLD. For simplicity, the letter "M" may be added to the device name (e.g., STA, AP, or MLD) to represent the MAC address of the device. For example, the MLD MAC addresses of an AP MLD and a non-AP MLD are represented as "AP-MLD-M" and "STA-MLD-M", respectively. When there are two non-AP MLDs named "non-AP MLD1" and "non-AP MLD2", these MLD MAC addresses are represented as "STA-MLD1-M" and "STA-MLD2-M", respectively. Similarly, the MAC addresses of an AP and a STA are represented as "AP-M" and "STA-M", respectively. When there are two APs and two STAs named "AP1", "AP2", "STA1", and "STA2", these MAC addresses are represented as "AP1-M", "AP2-M", "STA1-M", and "STA2-M", respectively.

[0023] Similar notations are applied to the IP addresses in the present disclosure. In particular, the characters "IP" are added to the device name (e.g., STA, AP, or MLD) to represent the IP address of the device. For example, the IP addresses of AP MLD and non-AP MLD are represented as "AP-MLD-IP" and "STA-MLD-IP", respectively. When there are two non-AP MLDs named "non-AP MLD1" and "non-AP MLD2", their IP addresses are represented as "STA-MLD1-IP" and "STA-MLD2-IP", respectively. Similarly, the IP addresses of AP and STA (regardless of whether they are attached to MLD) are represented as "AP-IP" and "STA-IP", respectively. When there are two APs named "AP1" and "AP2" and two STAs named "STA1" and "STA2", their IP addresses are represented as "AP1-IP", "AP2-IP", "STA1-IP", and "STA2-IP", respectively.

[0024] In various embodiments of the present disclosure, data frames can be used and exchanged between STA and AP to resolve ARP / ND queries. The data frame can include a Recipient Address (RA) field, a Transmitter Address (TA) field, a Destination Address (DA) field, and / or a Source Address (SA) field. The RA field indicates the MAC address of the recipient immediately after the data frame is sent. The TA field indicates the MAC address of the current sender that transmits the data frame. The DA field indicates the MAC address of the destination of the data frame. The SA field indicates the MAC address of the original sender of the data frame.

[0025] To resolve ARP queries, the data frame may further include an ARP message (ARP request or ARP reply) that includes a source hardware (Src.Hw.) field, a source IP (Src.IP) field, a target hardware (Hw) field, and a target IP field. The source hardware field indicates the MAC address of the sender that transmits the message. The source IP field indicates the IP address of the sender that transmits the message. The target hardware field indicates the MAC address of the recipient to which the message is transmitted. The target IP field indicates the IP address of the recipient to which the message is transmitted.

[0026] Tunnel direct link setup (TDLS) enables direct peer-to-peer communication between two non-AP STAs within an 802.11 basic service set (BSS). Figure 1 depicts a tunnel direct link setup between two non-AP STAs, namely STA-1 104 and STA-2 106, associated with an AP 102 within a BSS 100. Arrows 1a and 1b depict the transmission of a first management frame, such as a TDLS setup request frame, from STA-1 104 to STA-2 106 via the AP path, and arrows 2a and 2b depict the transmission of a management frame, such as a TDLS setup response frame, from STA-2 106 to STA-1 104 in response to the first management frame via the subsequent AP path. All management frames involved in the setup of TDLS (except for TDLS discovery responses) are encapsulated within a data frame, and thus the setup of TDLS is completely transparent to the AP 102 regardless of whether the AP 102 is TDLS-capable. When TDLS is set up, the two TDLS peer STAs, namely STA-1 104 and STA-2 106, can communicate directly with each other via a direct path as indicated by the two-way arrow 108. The direct path can also be switched to a channel different from the operating channel (base channel) of the BSS and may be on a different band. Such a direct path channel is called an "off-channel."

[0027] Currently, the AP does not control any setup / usage of TDLS. However, in the 6 GHz band, client devices are permitted to operate in the 6 GHz band only while under the control of the AP. When operating in the 5 GHz dynamic frequency selection (DFS) band, the TDLS initiator STA acts as the DFS owner (DO), but in the 6 GHz band, the TDLS STA may not have such an ability.

[0028] Enhanced direct link communication procedures have been proposed that allow for greater AP control over direct link communication in a specific band / channel. Without such enhancements, direct links such as TDLS may be prohibited in the 6 GHz band.

[0029] When operating in some sub-bands of the 6 GHz band (e.g., U-NII-5 and U-NII-7), the AP may need to refer to the AFC database (Automatic Frequency Control Database) to determine the allowable operating frequencies and transmission parameters. Such an AP may be known as an AFC Database Dependent (ADD) enabling STA, while non-AP STAs associated with such an AP may be known as ADD dependent STAs. The non-AP STA can communicate on channels in these sub-bands only when "enabled" by the enabling STA, and such a non-AP STA can be said to be under the "control" of the AP. The AP can indicate its presence by periodically transmitting an enabling signal, for example, by including such an enabling signal in a beacon frame on the channel on which enabling is required.

[0030] When two ADD dependent STAs negotiate a TDLS direct link on the base channel, the same transmission parameters used for the AP link can be used for transmission on the TDLS direct link.

[0031] Figures 2A and 2B depict two schematic diagrams 200, 210 that illustrate the methods performed for TDLS discovery. Figure 2A depicts the method for TDLS discovery performed using the TDLS discovery frame. In particular, the TDLS initiator STA, in this case STA1 202, transmits a TDLS discovery request frame to another STA204 via the AP path. If the other STA204 supports TDLS, the other STA204 transmits a TDLS discovery response frame via the direct path. Figure 2B depicts another method for TDLS discovery performed by exchanging access network query protocol (ANQP) request / response frames (a type of group address generic advertisement service (GAS) request / response frame) on the direct path between STA1 212 and STA2 214. In particular, the TDLS initiator STA, in this case STA1 212, transmits an ANQP request frame to another STA214 via the direct path. If the other STA214 supports TDLS, the other STA214 transmits an ANQP response frame via the direct path.

[0032] The problem of setting up a TDLS link in the 6 GHz band is addressed by the solution or method disclosed in Singapore Patent Application No. 1020196255Q. In particular, FIG. 3 depicts a flow diagram 300 illustrating TDLS setup in an off-channel in the 6 GHz band. AP 302 can be an ADD-enabled STA. Non-AP STAs 304 and 306 are associated with AP 302 in a channel in the 6 GHz band. For various reasons, non-AP STAs 304 and 306 can choose to communicate over a direct link on a channel different from the operating channel of the BSS. Due to the regulatory requirements in the 6 GHz band, it may be mandatory to ensure the availability of a channel from the AFC system before transmitting on the channel. Non-AP STA 304, as a TDLS initiator STA, can request permission from AP 302 to use a different channel in the 6 GHz band for direct link communication with non-AP STA 306 by transmitting a TDLS channel usage permission request frame 308 to AP 302. This channel can be, for example, a channel in the U-NII-5 or U-NII-7 sub-band of the 6 GHz band different from the base channel in the 6 GHz band used for communication between AP 302 and STAs 304 and 306.

[0033] After receiving the TDLS channel usage permission request frame 308 from STA304, the AP302 checks the AFC database (e.g., via the AFC system) regarding the availability of the requested channel. If successful, the AP302 may send a TDLS channel usage permission response frame 310 with a success status to STA304 to indicate that the requested channel is available for direct link communication. Then, STA304 may initiate the setup of a direct link on the requested channel with STA304 by sending a TDLS setup request frame 312 to STA306 via AP302. Then, STA306 may respond by sending a TDLS setup response frame 314 to STA304 via AP302. Thereafter, STA304 sends a TDLS setup confirmation frame 316 to STA306 via AP302, and a TDLS direct link is set up on the requested channel in the 6 GHz band. If unsuccessful, i.e., the requested channel is not available based on the AFC database check, the AP302 may send a TDLS channel usage permission response frame 310 with a failure status (e.g., TDLS_CHANNEL_USE_DENIED) to STA304 to indicate that permission to use the requested channel for direct link communication is not granted.

[0034] However, it is unclear how to discover and set up multi-link TDLS and direct link communication in the 6 GHz band in the MLD situation.

[0035] Furthermore, due to assumptions regarding the address resolution protocol (ARP) and neighbor discovery (ND) operations in MLD, there is an issue of address mismatch between TDLS and TDLS direct link communication. According to the IEEE802.11 proposal (IEEE802.11-2 / 1692r2), the following solutions are proposed to address the issue of address mismatch between TDLS setup and TDLS direct path communication: · Set the transmitter address (TA) field of the frame directly sent to the TDLS peer STA to the MAC address of the non-AP MLD. · Use the MLD MAC address in the link identifier element, and · Use the MLD MAC address during the TDLS peer key (TPK: TDLS PeerKey) handshake.

[0036] Figure 4 shows the configuration of the MLD400. According to the 802.11be document 0.3 (D0.3) specification, a multi-link device (MLD) (e.g., AP MLD400) has multiple attached APs (or STAs) and is described as a device having a single MAC service access point (SAP) 406 to a logical link control (LLC) that includes one MAC data service. The value of the address 2 (transmitted address (TA)) field of the MAC header of the frame sent over-the-air by the AP becomes the MAC address of the transmitting AP attached to the MLD400 corresponding to that link (e.g., link 1 408, link 2 410), except for the individual / group bit which is set to 1 when the TA field value is the bandwidth signaling TA and set to 0 otherwise. Similarly, the value of the address 1 (recipient address (RA)) field of the MAC header of the individually addressed frame sent over-the-air by the AP becomes the MAC address of the receiving AP attached to the MLD corresponding to that link (e.g., link 1 408, link 2 410).

[0037] However, the above definitions / addressing rules are for EHT MLD. However, the EHT AP is also a high efficiency (HE) / very high throughput (VHT) / high throughput (HT) AP and needs to support legacy STAs (HE / VHT / HT STAs). Legacy STAs do not understand the concept of MLD MAC addresses. Instead, legacy STAs only recognize the BSSID (i.e., the L2 MAC address) of the associated AP. This may also apply to non-MLD EHT STAs, which are EHT STAs not attached to MLD.

[0038] FIG. 5 shows a schematic diagram 500 illustrating the communication between APs 504, 506 attached to AP-MLD 502, non-MLD STA 542, and STAs 524, 526 attached to non-AP MLD 522. Each MLD, i.e., AP MLD 502 or non-AP MLD 522, has a single MAC SAP 508, 528 respectively. When the MAC SAPs 508, 528 are associated with their respective MLD MAC addresses 510, 530, their corresponding IP addresses are mapped to the MLD MAC addresses accordingly. Here, it is assumed that non-AP MLD 522 is associated with AP MLD 502 and non-MLD STA 542 is associated with AP 506.

[0039] In other words, APs 504, 506 of AP MLD 502 can communicate directly with STAs 524, 526 of non-AP MLD 522 via link 1 550 and link 2 552 respectively, while AP 2 506 can also communicate directly with legacy STA 542 via link 2 552.

[0040] When non-AP MLD(s) and legacy STAs are associated with a legacy (pre-EHT) AP or AP MLD, it is unclear how to discover and set up multi-link TDLS between two non-AP MLDs or between a non-AP MLD and a legacy STA.

[0041] Therefore, there is a need for a communication apparatus and method that provides a feasible technical solution for multi-link peer-to-peer communication to address one or more of the above problems in this way.

[0042] In the various embodiments below, the communication apparatus and method show the discovery and setup of multi-link peer-to-peer communication in the situations of (a) two non-AP MLDs via a related non-MLD AP, (b) two non-AP MLDs via a related MLD AP, (c) a non-AP MLD and a non-MLD STA via a related non-MLD AP, and (d) a non-AP MLD and a non-MLD STA via a related AP-MLD, as depicted in FIGS. 6A - 6D respectively.

[0043] According to various embodiments below, an MLD discovers and sets up one or more direct links with another MLD or non-MLD STA by exchanging discovery and setup frames (e.g., TDLS discovery request / response frames or ANQP request / response frames) on a single link. In one embodiment, a multi-link (ML) indication is included in a request frame (e.g., a TDLS discovery request frame or an ANQP request frame) to identify that the transmitting STA is attached to an MLD. In another embodiment, an ML element / field is included in a response frame (e.g., a TDLS discovery response frame or an ANQP response frame) transmitted in response to a request frame received from an STA of an MLD, and the ML element / field includes information about the MLD and information about at least one other link supported by the MLD. In yet another embodiment, an ML element including information about one or more direct links set up between two MLDs is included in a TDLS setup request / response / confirmation frame.

[0044] Also, in one embodiment, a security key (TPK) used to provide confidentiality and authentication for frames exchanged on all direct links is derived using a 3-way TPK handshake protocol performed on the setup link.

[0045] According to various embodiments, all multi-link functions (e.g., ML BlockAck, ML retransmission, ML encapsulation / de-encapsulation, etc., and ML power save) enabled between non-AP MLD and AP MLD are also available on the direct link. The TDLS channel switch protocol is utilized for the purpose of ML-TDLS link switching. The Quiet Time Protocol (QTP) mechanism is enhanced to provide QTP for multiple direct links. The Target Wake Time (TWT) mechanism is enhanced to provide a TWT service period (SP) for one or more direct links. Basically, one effect is that by enabling communication on one or more direct links, the advantages of the EHT multi-link function are extended to peer-to-peer communication.

[0046] FIG. 7 depicts a flow diagram 700 illustrating the setup of a set of direct links in link 1 and link 2 between two non-AP MLDs (non-AP MLD-1 704 and non-AP MLD-2 706) by using a single link 1 via a related AP / AP MLD 702 according to an embodiment of the present disclosure. In this embodiment, non-AP MLD-1 704 intends to set up a direct link with non-AP MLD-2 706. The STA of non-AP MLD-1 704 may initiate TDLS discovery by transmitting a data frame including a TDLS discovery request to non-AP MLD-2 706 via AP / AP-MLD 702 on link 1, and the TDLS discovery request includes an ML indication identifying that the transmitting STA belongs to non-AP MLD-1 704.

[0047] The AP MLD 702 receiving the data frame identifies that the TDLS discovery request included in the data frame is addressed to non-AP MLD-2 706 based on the MAC address included in the DA field of the data frame, and relays the data frame from non-AP MLD-1 704 to non-AP MLD-2 706.

[0048] The STA of the non-AP MLD-2 706 operating on Link 1 that receives the TDLS discovery request returns a TDLS discovery response action frame directly on Link 1 to the non-AP MLD-1 704. The TDLS discovery response action frame contains the information of Link 1 and also contains an ML element that contains the information of Link 2.

[0049] Based on the information of the operating link of the non-AP MLD-2 706, the non-AP MLD-1 704 may request the setup of TDLS on Link 1 and Link 2 by transmitting a data frame containing a TDLS setup request to the non-AP MLD-2 706 via the AP / AP MLD 702 on Link 1. The TDLS setup request contains an ML element that contains the information of Link 1 and Link 2 to be set up with the non-AP MLD2 706. The AP MLD 702 that receives the data frame identifies that the TDLS setup request contained in the data frame is addressed to the non-AP MLD-2 706 based on the MAC address contained in the DA field of the data frame, and relays the data frame from the non-AP MLD-1 704 to the non-AP MLD-2 706.

[0050] The STA of the non-AP MLD-2 706 operating on Link 1 that receives the TDLS setup request agrees to set up a direct link with the non-AP MLD-1 704 on Link 1 and Link 2, and may return a TDLS setup response action frame to the non-AP MLD-1 704 via the AP / AP MLD 702 on Link 1. The AP MLD 702 that receives the data frame identifies that the TDLS setup response contained in the data frame is addressed to the non-AP MLD-1 704 based on the MAC address contained in the DA field of the data frame, and relays the data frame from the non-AP MLD-2 706 to the non-AP MLD-1 704.

[0051] The STA of non - AP MLD - 1 704 operating on link 1 that receives the TDLS setup response confirms the setup of TDLS on link 1 and link 2 by transmitting a data frame including the TDLS setup confirmation to non - AP MLD - 2 706 via AP / AP MLD702 on link 1. The TDLS setup confirmation includes an ML element containing information on the operating links (link 1 and link 2) that have successfully set up with non - AP MLD - 2 706. The AP MLD702 that receives the data frame identifies, based on the MAC address included in the DA field of the data frame, that the TDLS setup confirmation included in the data frame is addressed to non - AP MLD - 2 706, and relays the data frame from non - AP MLD - 1 704 to non - AP MLD - 2 706. The STA of non - AP MLD - 2 706 operating on link 1 receives the TDLS setup confirmation. Thus, the multi - link TDLS setup between the two non - AP MLDs 704, 706 is completed, and the two non - AP MLDs 704, 706 can perform TDLS direct link communication on both link 1 and link 2.

[0052] In one embodiment, all direct links between the two non - AP MLDs 704, 706 can be disconnected through the transmission of a single TDL disconnection frame on any one link, in this case on link 1 from non - AP MLD - 1 704 to non - AP MLD - 2 706.

[0053] Figure 8 depicts an example of the use of a direct link setup in link 2 (e.g., a 6 GHz link) by using link 1 (e.g., a 5 GHz link) for home video conferencing using a mobile phone and a TV. Both the mobile phone 804 and the smart TV 806 are MLDs and are connected to the AP MLD 802 over the 5 GHz and 6 GHz links. A user wants to start a video call on the mobile phone 804 and use the TV 806 for a larger display / larger audio while using the phone's microphone and front camera as inputs. An ML-TDLS setup is initiated via AP1 808 of the AP MLD 802 over the 5 GHz link, and a direct link is set up between the mobile phone 804 and the TV 806 over the 6 GHz link and used to relay the video / audio output to the TV 806, while the 5 GHz link is used for the actual video call. The direct link is active in the 6 GHz link, while both STAs of the mobile phone 804 and the TV 806 can operate in power save mode with the AP MLD 802 at 6 GHz or be disabled (e.g., using mapping from TID to link). Alternatively, the ML-TDLS setup may be set up by exchanging TDLS setup frames on the 6 GHz link itself.

[0054] Another use case for setting up a direct link in Link 2 by using Link 1 is video casting from a smartphone 804 to a connected TV 806. A smartphone user wants to cast video and / or audio to a connected TV 806 within the same network (i.e., both the smartphone 804 and the TV 806 are associated with the same AP / AP-MLD 802). Here, it is assumed that the TV 806 has already been discovered in the upper-layer discovery protocol or using an out-of-band method such as NFC / Bluetooth. The user operates the video casting app to cast the video to the TV 806. In response to the action of the smartphone 804 user selecting the TV 806 as the casting destination in the application user interface (UI), the WLAN middleware (such as wpa_supplicant) is instructed to start TDLS discovery through the API. The STA of the smartphone 804 sends a TDLS discovery request in Link 1 (via the common associated AP) to discover the TDLS capabilities of the TV 806. The TV 806 returns a TDLS discovery response indicating its ML-TDLS capabilities via a direct path (e.g., Link 2). The STA of the smartphone 804 then continues to set up one or more direct link connections (Links 1 and 2) with the TV 806 using the ML-TDLS setup procedure in Link 1. Once the setup is complete, the video casting app starts casting the video from the smartphone 804 to the TV 806 over one or more direct links.

[0055] FIG. 9 shows a configuration example of a communication device according to the present disclosure. The communication device is implemented as an AP and an STA and can be configured for multi-link peer-to-peer communication according to the present disclosure. As shown in FIG. 9, the communication device 900 may include a circuit 914, at least one wireless transmitter 902, at least one wireless receiver 904, and at least one antenna 912 (only one antenna is depicted in FIG. 9 for illustrative purposes for simplicity). The circuit 914 may include at least one controller 906 for use in the software and hardware-assisted execution of tasks designed to be performed by at least one controller 906, including control of communication with one or more other communication devices in a multiple-input multiple-output (MIMO) wireless network. The circuit 914 may further include at least one transmission signal generator 908 and at least one reception signal processor 910. The at least one controller 906 may control the at least one transmission signal generator 908 to generate MAC frames (e.g., data frames, management frames, and action frames) to be sent through the at least one wireless transmitter 902, and the at least one reception signal processor 910 to process MAC frames (e.g., data frames, management frames, and action frames) received from one or more other communication devices through the at least one wireless receiver 904. The at least one transmission signal generator 908 and the at least one reception signal processor 910 may be stand-alone modules of the communication device 900 that communicate with the at least one controller 906 for the above-described functions, as shown in FIG. 9. Alternatively, the at least one transmission signal generator 908 and the at least one reception signal processor 910 may be included in the at least one controller 906. It is recognizable to those skilled in the art that the preparation of these functional modules is flexible and may 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 in a chipset.In various embodiments, during operation, at least one wireless transmitter 902, at least one wireless receiver 904, and at least one antenna 912 can be controlled by at least one controller 906.

[0056] Communication device 900 provides functions necessary for multi-link peer-to-peer communication during operation. For example, communication device 900 can be a STA among a plurality of STAs attached to a first MLD operating on a corresponding link of the first MLD. A circuit (e.g., at least one transmission signal generator 908 of circuit 914) can generate a request frame during operation. The request frame can be a discovery request frame for discovering the peer-to-peer communication capabilities of another communication device (a non-MLD STA or a non-AP MLD STA), or a setup request frame for requesting the setup of one or more direct links. The request frame includes a multi-link (ML) indication that identifies that the communication device is attached to the first MLD. The wireless transmitter 902 can transmit the request frame on one link during operation.

[0057] The wireless receiver 904 of communication device 900 can further receive, during operation, a response frame from another communication device that includes an ML element or an ML field containing information about the second MLD to which the other communication device is attached and information about at least one link supported by the second MLD.

[0058] Alternatively or in addition, the wireless receiver 904 may receive a request frame from another communication device during operation, where the request frame is one of a discovery request frame for discovering the peer-to-peer communication capabilities of the communication device 900 or a setup request frame for requesting the setup of one or more direct links. The circuit 914 (e.g., the received signal processor 910 of the circuit 914) determines during operation whether the received request frame includes an ML indication identifying that another communication device is attached to the second MLD, and in response to determining that the received request frame includes an ML indication identifying that another communication device is attached to the second MLD, sets the transmitter address (TA) field of the frame transmitted on one of the one or more direct links to the address included in the TDLS responder station (STA) address field of the link identifier element of the received request frame, and in response to determining that the received request frame does not include an ML indication identifying that another communication device is attached to the second MLD, sets the TA field of the frame transmitted on one of the one or more direct links to the media access control (MAC) address of the communication device attached to the second MLD that transmits the frame on one of the one or more direct links.

[0059] The circuit 914 (e.g., the transmitted signal generator 908 of the circuit 914) may further generate a response frame during operation that includes an ML element or an ML field that contains information about the first MLD to which another communication device is attached and information about at least one link supported by the first MLD. The wireless transmitter 902 may transmit the response frame on one link during operation.

[0060] For example, communication device 900 can be an AP among a plurality of APs attached to an AP MLD operating on a corresponding link of the AP MLD. During operation, wireless receiver 904 receives, on the link, a data frame whose destination address field is set to another related communication device not attached to the MLD from a related communication device attached to the MLD. Circuit 914 can set the source address field of the data frame to the MAC address of the related communication device during operation. Wireless transmitter 902 can transmit, during operation, the data frame with the set source address field to another related communication device.

[0061] FIG. 10 shows a flowchart 1000 illustrating a communication method according to the present disclosure. In step 1002, a step of generating a request frame is performed. The request frame is one of a discovery request frame for discovering the peer-to-peer communication capability of a communication device or a setup request frame for requesting setup of a set of one or more direct links. The request frame includes a multi-link indication identifying that another communication device transmitting the request frame is attached to the MLD. In step 1004, a step of transmitting the request frame is performed on one link.

[0062] In one embodiment, a new variant of the ML element called the TDLS ML element is used as an ML indication for indicating that the transmitting STA is attached to the MLD and for including related information related to the MLD and the links of the MLD. FIG. 11 depicts an example of a TDLS ML element 1100 according to an embodiment of the present disclosure. The TDLS ML element 1100 includes a multi-link control field including an element ID field, a length field, an element ID extension field, a type subfield 1102 and a presence bitmap subfield set to correspond to TDLS, a common information field 1104, and one or more link information fields 1106.

[0063] The common information field 1104 contains information about the MLD and other information common to all links. One or more link information fields 1106 contain information about other links related to the ML-TDLS. It is advantageous that the multi-link operation signaling can be reused for peer-to-peer signaling.

[0064] The encapsulated data frame (e.g., the Ethertype 89-0d data frame containing the TDLS payload) can be used as the TDLS discovery request frame. FIG. 12 shows an example format of the Ethertype 89-0d data frame 1200 and the link identifier element 1212 of the data frame 1200.

[0065] The Ethertype 89-0d data frame includes a frame control field, a duration field, an address 1 field, an address 2 field, an address 3 field, a sequence control field, a quality of service (QoS) control field, an HT control field, a logical link control (LLC) field, a subnetwork access protocol (SNAP) field 1202, a payload type field 1204, a payload field 1206, and a frame check sequence (FCS). The frame control field, the duration field, the address 1 field, the address 2 field, the address 3 field, the sequence control, the QoS control field, and the HT control field can be grouped as a MAC header, and the LLC field, the SNAP field 1202, the payload type field 1204, and the payload field 1206 can be grouped as a frame body. The SNAP field 1202 is set to the Ethertype of 89-0d, and the payload type field 1204 is set to correspond to TDLS. The payload field 1206 includes a category field 1208, a TDLS action field 1210, a dialog token field, a link identifier element 1212, and an ML element 1214. The category field 1208 is set to correspond to TDLS. The TDLS action field 1210 is set to correspond to a TLDS discovery request. The link identifier element 1212 includes an element ID subfield, a length subfield, a BSSID subfield, a TDLS initiator STA address subfield set to correspond to the MAC address of the STA that starts the TDLS discovery request, and a TDLS responder STA address subfield set to correspond to the MAC address of the STA that responds to the TDLS discovery request.The ML element 1214 includes a multi-link control subfield that includes an element ID subfield, a length subfield, an element ID extension subfield, a type field 1216, and a presence bitmap field.

[0066] In this embodiment, the ML element included in the TDLS discovery request frame 1200 can be a TDLS ML element and serves as an ML indication (sent on the AP path) that identifies that the transmitting STA is attached to a non-AP MLD. Different from the TDLS ML element 1100 depicted in FIG. 11, the TDLS ML element 1214 included in the TDLS discovery request frame 1200 may not include a common information field and one or more link information fields as depicted in FIG. 11. Alternatively, in the TDLS discovery request frame 1200, a probe request ML element can be used as an ML indicator.

[0067] When receiving a TDLS discovery request frame including an ML indication, if the receiving STA is also attached to an MLD, it transmits a TDLS response frame including a TDLS ML element that includes information such as the capabilities and MAC addresses of the MLD and the STA directly via a path on another link of the MLD (excluding the link indicated in the link identifier element).

[0068] Figure 13 shows an example format of a TDLS discovery response frame 1300 according to an embodiment of the present disclosure. The TDLS discovery response frame 1300 includes a frame control field, a duration field, an address 1 field, an address 2 field, an address 3 field, a sequence control field, an HT control field, a category field, a public action field, a dialog token field, a capability field, a link identifier element, an ML element, and an FCS. The frame control field, the duration field, the address 1 field, the address 2 field, the address 3 field, the sequence control, and the HT control field can be grouped as a MAC header, and the category field, the public action field, the dialog token field, the capability field, the link identifier element, and the ML element can be grouped as a frame body. The public action field 1302 is set to correspond to the TDLS discovery response. The link identifier element 1304 is the same as that of the TDLS discovery request frame depicted in FIG. 12.

[0069] The ML element 1306 included in the TDLS discovery response frame 1300 can be a TDLS ML element and serves as an ML indication (sent via the AP path) that identifies that the transmitting STA belongs to a non-AP MLD. Similar to the TDLS ML element depicted in FIG. 11, the ML element 1306 includes a multi-link control field including an element ID field, a length field, an element ID extension field, a type field 1308 and a presence bitmap field, a common information field 1310, and one or more link information fields 1312. The common information field 1310 includes information about the MLD and other information common to all links. The one or more link information fields 1312 include information about other links related to ML-TDLS (excluding the link indicated in the link identifier element).

[0070] In particular, the common information field 1310 includes an MLD MAC address sub-field 1314 set to correspond to the MLD MAC address of the transmitting non-AP MLD, an STA MAC address sub-field 1316 set to correspond to the MAC address of the transmitting STA, a transmitting link ID sub-field 1318 set to correspond to the link ID assigned to the link on which the TDLS response frame is transmitted, a supported direct link count sub-field 1320 set to indicate the number of direct links supported by the MLD, and a TDLS link switching support sub-field 1322 set to indicate whether the MLD supports switching of the TDLS link. Each of the link information fields 1312 includes a link ID sub-field 1324 set to correspond to the link ID assigned to one of the other links of the MLD, a capability sub-field, and a MAC address sub-field 1326 set to the corresponding MAC address of one of the other links.

[0071] For easier identification, the TDLS response MLD can also assign a link ID to that link that can be the same as the link ID assigned to the link by the associated AP MLD. If the STA that receives the TDLS discovery request is not attached to the MLD, the STA returns a normal TLD discovery response frame that does not include the ML element 1306.

[0072] According to the conventional rules, the TA field and the TDLS responder field of a data frame including a discovery response frame must contain the same address. However, when the TDLS responder is an MLD, the TDLS responder field can be set as the MLD MAC address of the TDLS responder. In such a case, the TA field of the discovery response frame can be verified using the STA MAC address included in the common information field 1310 of the ML element 1306 of the TDLS discovery response frame 1300 by the TDLS initiator STA. The MAC address(es) in the link information field of the ML element indicate(s) the MAC address(es) of the STA(s) attached to the peer MLD on another link and can be used for communication with the STA on another direct link.

[0073] To set up multiple direct links between two MLDs, the two MLDs can exchange TDLS setup (request / response / confirmation) frames including TDLS ML elements via the AP path. Encapsulated data frames (e.g., Ethertype 89-0d data frames accommodating TDLS payloads) can be used as TDLS setup frames. FIG. 14 shows an example format of an Ethertype 89-0d data frame 1400 used as a TDLS setup frame according to an embodiment of the present disclosure.

[0074] The Ethertype 89-0d data frame includes a frame control field, a duration field, an address 1 field, an address 2 field, an address 3 field, a sequence control field, a QoS control field, an HT control field, an LLC field, a SNAP field 1402, a payload type field 1404, a payload field 1406, and an FCS. The frame control field, the duration field, the address 1 field, the address 2 field, the address 3 field, the sequence control, the QOS control field, and the HT control field can be grouped as a MAC header, and the LLC field, the SNAP field 1402, the payload type field 1404, and the payload field 1406 can be grouped as a frame body. The SNAP field 1402 is set to the Ethertype of 89-0d, and the payload type field 1404 is set to correspond to TDLS. The payload field 1406 includes a category field 1408, a TDLS action field 1410, a dialog token field, a link identifier element 1412, and an ML element 1414. The category field 1408 is set to correspond to TDLS. The TDLS action field 1410 is set to correspond to TLDS setup request / response / confirmation.

[0075] The link identifier element 1412 is used for TPK generation. The ML element 1414 included in the TDLS setup frame 1400 can be a TDLS ML element and acts as an ML indication (sent via the AP path) that identifies that the transmitting STA is attached to a non-AP MLD. Similar to the TDLS ML element depicted in FIG. 11, the ML element 1414 includes a multi-link control field including an element ID field, a length field, an element ID extension field, a type field 1416, and a presence bitmap field, a common information field 1418, and one or more link information fields 1420. The common information field 1418 includes an MLD MAC address subfield set to correspond to the MLD MAC address of the transmitting non-AP MLD. Each of the link information fields 1420 includes a link ID subfield, a link identifier element 1422, and a capability / operation subfield 1424. The link identifier element 1422 corresponds to the link ID of one other link including the MAC address(es) of the STA(s) of the transmitting MLD operating on one or more other links. Alternatively, the MAC address of the transmitting STA is included instead of the link identifier element. The capability / operation subfield 1424 includes parameters of one or more other link(s).

[0076] In the capability / operation field 1424, the TDLS setup request / response may include an HT / VHT / HE / EHT capability element, while the TDLS setup confirmation frame includes an HT / VHT / HE / EHT operation element, etc. When only a single direct link is set up on the transmitting link itself, the ML element 1414 includes only the common information field 1418 including the MLD MAC address of the transmitting MLD. Other fields such as the STA MAC address of the transmitting STA, the link ID assigned to the transmitting link, and the ML-TDLS capability may also be included in the common information field 1418. The MLD MAC address may be used to generate the AAD and Nonce fields used to protect the frames exchanged on the direct link.

[0077] In the following paragraphs, embodiments are described with reference to the ML-TDLS setup between two non-AP MLDs via a non-MLD (legacy) AP for multi-link peer-to-peer communication.

[0078] FIG. 15 depicts a flowchart 1500 illustrating communication between two non-AP MLDs 1512, 1522 via a non-MLD AP 1504 for multi-link peer-to-peer communication according to an embodiment of the present disclosure. The communication is divided into a discovery phase 1501, a setup phase 1502, and a direct link communication 1503. Here, the non-AP MLDs 1512, 1522 are associated with the AP 1504 on link 2 (5 GHz band).

[0079] In the discovery phase 1501, the STA2 1514 of the non-AP MLD1 1512 may initiate TDLS discovery by transmitting a data frame 1532 including a TDLS discovery request 1534 to the STA4 1524 of the non-AP MLD2 1522 via the AP 1504. The TDLS discovery request 1534 includes a TDLS initiator field set to the MAC address of STA2 (STA2-M), a TDLS responder field set to the MAC address of STA4 (STA4-M), and an ML element indicating that the STA2 1514 belongs to the non-AP MLD1 1512.

[0080] AP 1504 that receives data frame 1532 identifies, based on the MAC address of STA4 in the DA field, that the TDLS discovery request 1534 included in data frame 1532 is addressed to STA4 1524 of its associated non-AP MLD2 1522, and transfers data frame 1532' received from non-AP MLD1 1512, which includes the MAC address of STA2 in the SA field (STA2-M) and TDLS discovery request 1534', to STA4 1524. When transferring data frame 1532' to STA4 1524, AP 1504 also sets the MAC address of STA4 (STA4-M) in the RA field. Therefore, the data frame is correctly received by STA4 1524.

[0081] STA4 1524 that receives TDLS discovery request 1534' can directly link, i.e., return on the operation link of STA2 (link 2), a TDLS discovery response action frame 1542 that includes an ML element containing information on other STAs (STA3 1523) attached to non-AP MLD2 1522 in addition to the information of non-AP MLD2 1522, to STA2 1514. Based on the TDLS initiator field, STA4 1524 can set the RA field of TDLS discovery response action frame 1542 to the MAC address of STA2 (STA2-M). Therefore, frames such as TDLS discovery response action frame 1542 sent directly on the link to non-AP MLD 1512 by STA4 1524 are correctly received via STA2 1514.

[0082] In a subsequent setup stage 1502, non-AP MLD1 1512 can initiate a TDLS setup with non-AP MLD2 1522 via AP1504 by sending a further data frame 1552 including a TDLS setup request 1554 from STA2 1514 to STA4 1524 via AP1504. The data frame 1552 includes a DA field set to the MAC address of STA4 (STA4-M). The TDLS setup request 1554 includes a TDLS responder field set to the MAC address of STA4 (STA4-M), a TDLS initiator field set to the MAC address of STA2 (STA2-M), and an ML element indicating that STA2 is attached to non-AP MLD1 1512. The ML element includes information of other STAs (i.e., STA1 1513) attached to non-AP MLD1 1512 in addition to the information of non-AP MLD1 1512.

[0083] Based on the STA MAC address in the DA field, AP1504 identifies that the further data frame 1552 is addressed to STA4 1524 of its associated non-AP MLD2 1522, and transfers the further data frame 1552 to STA4 1524. When transferring the data frame 1552 to STA4 1524, AP1504 also sets the RA field to the MAC address of STA4 (STA4-M). Therefore, the data frame 1552 is correctly received by STA4 1524.

[0084] STA4 1524 that receives the TDLS setup request 1554 can respond by sending back to STA2 1514 at link 2 via AP1504 another data frame 1562 that includes the TDLS setup response 1564. The TDLS setup response 1562 includes a DA field set to the MAC address of STA2 (STA2-M), as well as a TDLS initiator field and a TDLS responder field each set to the same MAC address as that of the TDLS setup request 1554, and an ML element that includes information of non-AP MLD2 1522 and information of another STA (i.e., STA3 1523) attached to non-AP MLD2 1522 in addition to the information of non-AP MLD2 1522.

[0085] Upon receiving the data frame 1562, AP1504 identifies, based on the MAC address of STA2 in the DA field, that the data frame 1562 is addressed to STA2 1514 of its associated non-AP MLD1 1512, and transfers the data frame 1562 to STA2 1514. When transferring the data frame 1562 to STA2 1514, AP1504 also sets the MAC address of STA2 (STA2-M) in the RA field. Therefore, the data frame is correctly received by STA2 1514.

[0086] Subsequently, STA2 1514 sends to STA4 1524 via AP1504 a data frame 1572 that includes the TDLS setup confirmation 1574. The TDLS setup confirmation 1574 includes a DA field set to the MAC address of STA4 (STA4-M), as well as a TDLS initiator field and a TDLS responder field each set to the same MAC address as that of the TDLS setup request 1554, and an ML element that includes information of non-AP MLD1 1512 and information of another STA (i.e., STA1 1513) attached to non-AP MLD1 1512 in addition to the information of non-AP MLD1 1512.

[0087] Based on the STA MAC address in the DA field, AP1504 identifies that data frame 1572 is addressed to STA4 1524 of its associated non-AP MLD2 1522, and transfers data frame 1572 to STA4 1524. When transferring data frame 1572 to STA4 1524, AP1504 also sets the RA field to the MAC address of STA4 (STA4-M). Therefore, data frame 1572 is correctly received by STA4 1524, and the multi-link TDLS setup phase is completed.

[0088] When the TDLS setup between non-AP MLD1 1512 and non-AP MLD2 1522 is completed, any two STAs from non-AP MLD1 1512 and non-AP MLD2 1522 can perform multi-link peer-to-peer communication directly with each other, and transmit data frames via a direct path on Link 1 and Link 2. For example, STA2 and STA4 can exchange data frames 1582 and 1592 via a direct path on both Link 1 and Link 2.

[0089] When non-AP MLD1512 and 1522 are associated with legacy AP1504, their respective MLD MAC addresses can be used as link MAC addresses by STA1 1513 and STA3 1523. In this case, since the STA MAC address is used in all cases, addressing in frames (both on the AP path and the direct path) as well as in the link ID element is straightforward. When other links are set up on DFS channels or channels in the 6 GHz band, since the STA is not associated with any AP on other links, the STA can only operate on channels where at least one AP can be heard, and the BSSID of the BSS of the AP can be used. The receiver can verify the TA field based on the MAC address included in the ML element during the setup phase. When other links are set up on normal channels (i.e., not DFS channels or not in the 6 GHz band), the requirement to hear at least one AP on that channel is waived, and the BSSID field can also be set to the MAC address of one of the peer STAs or the BSSID of the BSS with which the STA is associated.

[0090] In the following paragraphs, embodiments are described with reference to the ML-TDLS setup between two non-AP MLDs via an AP MLD for multi-link peer-to-peer communication.

[0091] FIG. 16 depicts a flowchart 1600 illustrating communication between two non-AP MLDs 1612 and 1622 via a non-MLD AP 1604 for multi-link peer-to-peer communication according to an embodiment of the present disclosure. The communication is divided into a discovery phase 1601, a setup phase 1602, and a direct link communication 1603.

[0092] In the discovery stage 1601, STA2 1614 of non-AP MLD1 1612 can initiate TDLS discovery by transmitting a data frame 1632 including a TDLS discovery request 1634 to non-AP MLD2 1622 via AP MLD 1604. The data frame 1632 includes a DA field set to the MAC address of non-AP MLD2 (STA-ML2-M). The TDLS discovery request 1634 includes a TDLS initiator field set to the MAC address of STA2 (STA2-M), a TDLS responder field set to the MLD MAC address of non-AP MLD2 (STA-ML2-M), and an ML element indicating that STA2 1614 belongs to non-AP MLD1 1612.

[0093] Upon receiving the data frame 1632, AP MLD 1604 identifies, based on the MLD MAC address of non-AP MLD2 in the DA field, that the TDLS discovery request 1634 included in the data frame 1632 is addressed to non-AP MLD2 1622, and transfers the data frame 1632' received from non-AP MLD1 1612 to one of the associated STAs of non-AP MLD2, for example STA4 1624 in this embodiment. AP MLD 1604 also sets the MAC address of STA4 (STA4-M) in the RA field when transferring the data frame 1632' to STA4 1624. Therefore, the data frame is correctly received by STA4 1624.

[0094] The STA4 1624 that receives the TDLS discovery request 1634' can directly link the TDLS discovery response action frame 1642 containing an ML element that includes information on other STAs (STA3 1623) attached to the non-AP MLD2 1622 in addition to the information on the non-AP MLD2 1622 to the STA2 1614, that is, return it on the operational link of the STA2 (link 2). The STA4 1624 can set the RA field of the TDLS discovery response action frame 1642 to the MAC address of the STA2 (STA2-M) based on the TDLS initiator field of the TDLS discovery request 1634'. Therefore, frames such as the TDLS discovery response action frame 1642 sent directly to the non-AP MLD 1612 by the STA4 1624 on the link can be correctly received via the STA2 1614.

[0095] In the subsequent setup stage 1602, the non-AP MLD1 1612 can initiate a TDLS setup with the non-AP MLD2 1622 via the AP MLD 1604 by transmitting a further data frame 1652 containing the TDLS setup request 1654 from the STA2 1614 via the AP MLD 1604 to the non-AP MLD2 1622. The data frame 1652 includes a DA field set to the MAC address of the non-AP MLD2 (STA-ML2-M). The TDLS setup request 1654 includes a TDLS responder field set to the MLD MAC address of the non-AP MLD2, a TDLS initiator field set to the MAC address of the STA2 (STA2-M), and an ML element indicating that the STA2 is attached to the non-AP MLD1 1612. The ML element includes information on other STAs (i.e., STA1 1613) attached to the non-AP MLD1 1612 in addition to the information on the non-AP MLD1 1612.

[0096] Based on the MLD MAC address of non - AP MLD2 in the DA field, the AP MLD1604 identifies that a further data frame 1652 is addressed to its associated non - AP MLD2 1622, and transfers the further data frame 1652 to one of the attached STAs of non - AP MLD2 1622, for example STA3 1623 in this embodiment. When transferring the data frame 1652 to STA3 1623, the AP MLD1604 also sets the RA field to the MAC address of STA3 (STA3 - M). Therefore, the data frame 1652 is correctly received by STA3 1623.

[0097] Since the TDLS frame indicates the DA as the MLD MAC address, a crossover may occur when the AP MLD relays the TDLS frame (i.e., the frame, for example, the above - mentioned TDLS setup request frame 1652 is relayed on a different link). However, the receiving non - AP MLD can correctly identify the transmitting STA and its link by referring to the TDLS initiator address and the BSSID field of the link identifier element included in the TDLS frame (not the ML element), and can respond accordingly.

[0098] Regarding this, even if a crossover from link 2 to link 1 has occurred, the non - AP MLD2 1622 that receives the TDLS setup request 1654 can respond by returning another data frame 1662 including the TDLS setup response 1664 to STA2 1614, that is, the TDLS initiator, via the AP MLD1604 from STA4 1624. The data frame 1662 includes a DA field set to the MLD MAC address of non - AP MLD1 (STA - ML1 - M). The TDLS setup responses 1664 each include a TDLS initiator field and a TDLS responder field set to the same MAC addresses as those of the TDLS setup request 1654, and an ML element including information of other STAs attached to non - AP MLD2 1622 (i.e., STA3 1623) in addition to the information of non - AP MLD2 1622.

[0099] AP MLD1604 that receives data frame 1662 identifies, based on the MAC address in the DA field, that data frame 1662 is addressed to non-AP MLD1 1612, and transfers data frame 1662 to one of the associated STAs of non-AP MLD1 1612 (for example, STA2 1614). When transferring data frame 1662 to STA2 1614, AP MLD1604 also sets the MAC address of STA2 (STA2-M) in the RA field. Therefore, the data frame is correctly received by STA2 1614.

[0100] Subsequently, STA2 1614 transmits a data frame 1672 including a TDLS setup confirmation 1674 to STA4 1624 via AP MLD1604. The TDLS setup confirmation 1674 includes a DA field set to the MLD MAC address of non-AP MLD2 (STA-ML2-M), and a TDLS responder field and a TDLS initiator field each set to the same MAC address as that of the TDLS setup request 1654, and an ML element including information of another STA (i.e., STA1 1613) attached to non-AP MLD1 1612 in addition to the information of non-AP MLD1 1612.

[0101] AP MLD1604 identifies, based on the MAC address in the DA field, that data frame 1672 is addressed to non-AP MLD2 1622, and transfers data frame 1672 to one of the associated STAs of non-AP MLD2 1622, for example, STA4 1624 in this embodiment. When transferring data frame 1672 to STA4 1624, AP MLD1604 also sets the RA field to the MAC address of STA4 (STA4-M). Therefore, data frame 1672 is correctly received by STA4 1624, and the setup phase is completed.

[0102] When the TDLS setup between non-AP MLD1 1612 and non-AP MLD2 1622 is completed, any two STAs from non-AP MLD1 1612 and non-AP MLD2 1622 can perform multi-link peer-to-peer communication directly with each other and transmit data frames via a direct path in Link 1 and Link 2. For example, STA2 and STA4 can exchange data frames 1682 and 1692 via a direct path in both Link 1 and Link 2. In this case, the BSSID field of the data frame transmitted on the direct link is set to the respective associated BSSID. The following are some detailed points regarding Flow 1600.

[0103] Since the IP address is associated with the MLD MAC address (reply by ARP), initially STA1 1613 only knows the MLD MAC address of non-AP MLD2. The TDLS initiator STA address and BSSID field of the link identifier element identify the link on which the initiator STA and TDLS discovery response frame 1642 should be transmitted.

[0104] The content of the TDLS discovery request frame 1632 is the same in this case, except that the TDLS responder STA address becomes the MAC address of STA2 even if the recipient is a non-MLD (since the transmitter does not know whether the recipient is an MLD).

[0105] Here, in the TDLS discovery response frame 1642, it should be noted that the TA field is set as the MAC address of the transmitting STA (STA4-M), which is different from the TDLS responder STA address field in the link identifier element. This behavior is different from the baseline TDLS behavior. However, since the recipient is also an MLD and already recognizes the STA MAC address (included in the common information field of the ML element) through the ML element, the TA field of the discovery response frame can be verified even if the TDLS responder STA address field is set as the MLD MAC address.

[0106] In the following paragraphs, embodiments will be described with reference to the ML-TDLS setup between a non-AP MLD and a non-MLD STA via an AP MLD for multi-link peer-to-peer communication, where the setup is initiated by the non-AP MLD.

[0107] FIG. 17 depicts a flowchart 1700 illustrating communication between a non-AP MLD 1712 and a non-MLD STA (STA3) 1722 via a non-MLD AP 1704 for multi-link peer-to-peer communication according to an embodiment of the present disclosure. The communication is divided into a discovery phase 1701, a setup phase 1702, and a direct link communication 1703.

[0108] In the discovery phase 1701, the STA2 1714 of the non-AP MLD1 1712 can initiate TDLS discovery by transmitting a data frame 1732 including a TDLS discovery request 1734 to the STA3 1722 via the AP MLD 1704. The data frame includes a DA field set to the MAC address of the STA3. The TDLS discovery request 1734 includes a TDLS initiator field set to the MAC address of the STA2 (STA2-M), a TDLS responder field set to the MAC address of the STA3, and an ML element indicating that the STA2 1714 belongs to the non-AP MLD1 1712.

[0109] AP MLD1704 that receives data frame 1732 identifies that the TDLS discovery request 1734 included in data frame 1732 is addressed to STA3 1722 based on the MAC address of STA3 in the DA field, and transfers data frame 1732' including TDLS discovery request 1734' received from non-AP MLD1 1712 to STA3 1722.

[0110] Normally, AP MLD1704 can set the SA field of the transferred data frame to the MLD MAC address of the non-AP MLD. However, when transferring to a non-MLD STA (e.g., legacy STA STA3 1722), the SA field is set to the MAC address of the transmitting STA of non-AP MLD1 1712, in this case, the MAC address of STA2 (STA2-M). The TDLS responder (STA3 1722) can correctly set the RA of the subsequent discovery response action frame sent directly based on the SA and / or TDLS initiator MAC address of the received data frame including the discovery request frame. This avoids the need for the STA of the non-AP MLD to filter the received frame based on the MLD MAC address.

[0111] When transferring data frame 1732', AP MLD1704 also sets the MAC address of STA3 (STA3-M) in the RA field when transferring data frame 1732' to STA3 1722. Therefore, the data frame is correctly received by STA3 1722.

[0112] The STA3 1722 that receives the TDLS discovery request 1734’ can return the TDLS discovery response action frame 1742 directly on the link (link 2) to the STA2 1714. The STA3 1722 can set the RA field of the TDLS discovery response action frame 1742 to the MAC address of the STA2 (STA2-M). Therefore, frames such as the TDLS discovery response action frame 1742 sent directly on the link by the STA3 1722 to the non-AP MLD1612 can be correctly received via the STA2 1714. Since the STA3 1722 is not an MLD, it must be noted that the TDLS discovery response frame 1742 does not contain an ML element.

[0113] In the subsequent setup stage 1702, the non-AP MLD1 1712 can initiate a TDLS setup with the STA3 1722 via the AP MLD1704 by sending a further data frame 1752 containing the TDLS setup request 1754 from the STA2 1714 via the AP MLD1704 to the STA3 1722. The data frame includes a DA field set to the MAC address of the STA3. The TDLS setup request 1754 includes a TDLS responder field set to the MAC address of the STA3 and a TDLS initiator field set to the MAC address of the STA2 (STA2-M). Since the non-AP MLD1 1712 now knows that the STA3 1722 is not an MLD (because the TDLS discovery response frame does not contain an ML element), it must be noted that the TDLS setup request 1752 does not contain an ML element.

[0114] AP MLD1704 identifies that a further data frame 1752 is addressed to STA3 1722 based on the MAC address of STA3 in the DA field, and transfers the further data frame 1752 to STA3 1722. When transferring the data frame 1752 to STA3 1723, AP MLD1704 also sets the RA field to the MAC address of STA3 (STA3-M). Therefore, the data frame 1752 is correctly received by STA3 1722.

[0115] Upon receiving the TDLS setup request 1754, STA3 1722 may respond by returning another data frame 1762 including a TDLS setup response 1764 to STA2 1714, i.e., the TDLS initiator, via AP MLD1704. The data frame includes a DA field set to the MLD MAC address of non-AP MLD1. The TDLS setup responses 1764 each include a TDLS initiator field and a TDLS responder field, both set to the same MAC address as that of the TDLS setup request 1754.

[0116] Upon receiving the data frame 1762, AP MLD1704 identifies that the TDLS setup response 1764 included in the data frame 1762 is addressed to non-AP MLD1 1712 based on the MLD MAC address of non-AP MLD1 in the DA field, and transfers the data frame 1762 to one of the associated STAs of non-AP MLD1712, e.g., STA2 1714 in this embodiment. When transferring the data frame 1762 to STA2 1714, AP MLD1704 also sets the RA field to the MAC address of STA2 (STA2-M). Therefore, the data frame is correctly received by STA2 1714.

[0117] Subsequently, STA2 1714 transmits a data frame 1772 including a TDLS setup confirmation 1774 to STA3 1722 via AP MLD1704. The data frame 1772 includes a DA field set to the MAC address of STA3 (STA3-M). The TDLS setup confirmation 1774 includes a TDLS initiator field and a TDLS responder field, each set to the same MAC address as that of the TDLS setup request 1754. It should be noted that the TDLS setup confirmation 1772 does not include an ML element.

[0118] Based on the MAC address in the DA field, AP MLD1704 identifies that the data frame 1772 is addressed to STA3 1772 and transfers the data frame 1772 to STA3 1722. When transferring the data frame 1772 to STA3 1722, AP MLD1704 also sets the RA field to the MAC address of STA3 (STA3-M). Therefore, the data frame 1772 is correctly received by STA3 1722, and the setup phase is completed.

[0119] When the TDLS setup between non-AP MLD1 1712 and STA3 1722 is completed, STA2 1714 of non-AP MLD1 1712 and STA3 can perform direct multi-link peer-to-peer communication with each other and transmit data frames via a direct path on a common operating link (Link 2).

[0120] In the following paragraphs, embodiments are described with reference to the ML-TDLS setup between a non-AP MLD and a non-MLD STA via an AP MLD for multi-link peer-to-peer communication initiated by the non-MLD STA.

[0121] To perform a TDLS setup with a non-AP MLD via an AP MLD initiated by a non-MLD STA, there are two possible options. In Option 1, regardless of the TDLS responder STA address field in the link identifier element, the non-AP MLD sets the TA of the TDLS discovery response frame as the MAC address of the transmitting STA (STA2-M). Based on this, during direct link communication, the same (STA's) MAC address is used in the RA field. However, in this option, there is a risk that a legacy STA (STA3) may reject the TDLS discovery response frame due to a mismatch between the TA field and the TDLS responder STA address field in the link identifier element.

[0122] In Option 2, when receiving a TDLS discovery request frame in the legacy format (identified by the absence of an ML indication), the TDLS responder simply uses the address (MLD MAC address or STA MAC address) used in the TDLS responder STA address field of the link identifier element of the TDLS discovery request frame as the TA field of the TDLS discovery response frame. The selection of the address set in the TDLS responder field of the link identifier element of the TDLS frame and the RA field of the frame transmitted on the direct link by the legacy device depends on its knowledge of the MAC address of the TDLS responder STA, which can be affected, for example, by the way the MLD returns the MAC address via the ARP protocol. Alternatively, the legacy STA can learn the STA MAC address through its past communication with the STA or by listening to the wireless medium. By adapting the TA field of the TDLS discovery response frame (or the data frame transmitted on the direct path), it is guaranteed that the legacy STA will not reject the TDLS discovery response frame due to a mismatch between the TA field and the TDLS responder STA address field. The same address is also used as the TA for all frames transmitted on the direct link.

[0123] FIG. 18 depicts a flowchart 1800 illustrating communication between a non-AP MLD 1812 and a non-MLD STA (STA3) 1822 via a non-MLD AP 1804 for multi-link peer-to-peer communication according to another embodiment of the present disclosure in accordance with Option 1 described above. The communication is divided into a discovery phase 1801, a setup phase 1802, and a direct link communication 1803.

[0124] In the discovery phase 1801, STA3 1822 may initiate TDLS discovery by transmitting a data frame 1832 including a TDLS discovery request 1834 via the AP MLD 1804 to the non-AP MLD1 1812. The data frame 1832 includes a DA field set to the MAC address of the non-AP MLD1 (STA-ML1-M). Since the IP address is associated with the MLD MAC address (reply by ARP), initially STA3 1822 only knows the MLD MAC address of the non-AP MLD1. The TDLS discovery request 1834 includes a TDLS initiator field set to the MAC address of STA3 (STA3-M), and a TDLS responder field set to the MLD MAC address of the non-AP MLD1 (STA-ML1-M). The TDLS initiator STA address and the BSSID field of the link identifier element identify the link to which the initiator STA 1822 and the TDLS discovery response frame 1832 should be transmitted. The content of the TDLS discovery request frame is the same even if the recipient is a non-MLD (since STA3 1822 does not know whether the recipient is an MLD).

[0125] AP MLD1804 that receives data frame 1832 identifies that the TDLS discovery request 1834 included in data frame 1832 is addressed to a non-AP MLD based on the MLD MAC address in the DA field, and transfers data frame 1832' that includes TDLS discovery request 1834' received from STA3 1822 to one of the associated STAs of non-AP MLD1 1812, for example STA1 1813 in this case, thus causing a crossover to Link 1. When transferring data frame 1832' to STA1 1813, AP MLD1804 sets the MAC address of STA1 (STA1-M) in the RA field. Therefore, the data frame is correctly received by STA1 1813.

[0126] Non-AP MLD1812 that receives TDLS discovery request 1834' can directly return the TDLS discovery response action frame 1842 on the link from STA2 1814, which operates on the same link as one of the associated STAs, for example non-MLD STA3 1822 in this embodiment, to STA3 1822. Non-AP MLD1812 sets the MAC address of the transmitting STA (STA2 1814) in the TA field of the TDLS discovery response action frame 1842, and also sets the MAC address of STA3 (STA3-M) in the RA field of the TDLS discovery response action frame 1842. Therefore, frames such as the TDLS discovery response action frame 1842 sent directly on the link from STA2 1814 to STA3 1822 are correctly received via STA3 1822. Importantly, under Option 1, the MAC address of the transmitting STA in the TA field of the TDLS discovery response action frame 1842 can be used to set the RA field of the data frame transmitted by STA3 1822 in the direct link communication 1803.

[0127] In a subsequent setup stage 1802, STA3 1822 can initiate a TDLS setup with non-AP MLD1812 via AP MLD1804 by transmitting a further data frame 1852 containing a TDLS setup request 1854 from STA3 1822 to non-AP MLD1812 via AP MLD1804. The data frame 1852 includes a DA field set to the MLD MAC address of the non-AP MLD (STA-ML1-M). The TDLS setup request 1854 includes a TDLS responder field set to the MLD MAC address of the non-AP MLD and a TDLS initiator field set to the MAC address of STA3 (STA3-M).

[0128] AP MLD1804 identifies that the further data frame 1852 is addressed to non-AP MLD1 1812 based on the MLD MAC address in the DA field, and transfers the further data frame 1852 to one of the associated STAs of non-AP MLD1 1812, for example STA2 1814 in this embodiment. AP MLD1804 also sets the RA field to the MAC address of STA2 (STA2-M) when transferring the data frame 1852 to STA2 1814. Therefore, the data frame 1852 is correctly received by STA2 1814.

[0129] Upon receiving the TDLS setup request 1854, non-AP MLD1812 can respond by transmitting another data frame 1862 containing a TDLS setup response 1864 to STA3 1822, i.e., the TDLS initiator, via AP MLD1804. The data frame 1862 includes a DA field set to the MAC address of STA3. The TDLS setup response 1864 includes a TDLS initiator field and a TDLS responder field, both set to the same MAC addresses as those of the TDLS setup request 1854 respectively.

[0130] AP MLD1804 that receives data frame 1862 identifies that the TDLS setup response 1864 included in data frame 1862 is addressed to STA3 1822 based on the MAC address of STA3 in the DA field, and transfers data frame 1862 to STA3 1822. When transferring data frame 1862 to STA3 1822, AP MLD1804 also sets the MAC address of STA3 (STA3-M) in the RA field. Therefore, the data frame is correctly received by STA3 1822.

[0131] Subsequently, STA3 1822 transmits a data frame 1872 including a TDLS setup confirmation 1874 to non-AP MLD1 1812 via AP MLD1804. The data frame includes a DA field set to the MAC address of non-AP MLD1 (STA-ML1-M). Each of the TDLS setup confirmations 1874 includes a TDLS responder field and a TDLS initiator field, both set to the same MAC address as that of the TDLS setup request 1854.

[0132] AP MLD1804 identifies that data frame 1872 is addressed to non-AP MLD1 1812 based on the MLD MAC address in the DA field, and transfers data frame 1872 to one of the associated STAs of non-AP MLD1, for example STA2 1814 in this embodiment. When transferring data frame 1872 to STA2 1814, AP MLD1804 also sets the RA field to the MAC address of STA2 (STA2-M). Therefore, data frame 1872 is correctly received by STA2 1814, and the setup phase is completed.

[0133] When the TDLS setup between the non-AP MLD1 1812 and the STA3 is completed, the STA2 1814 and the STA3 1822 of the non-AP MLD1 can perform direct multi-link peer-to-peer communication with each other and transmit the data frame 1882 via a direct path on a common operating link (Link 2). The RA of such a data frame 1882 is set as the MAC address of the receiving STA based on the TA of the discovery response action frame 1842. However, as described above, in this option, there is a risk that the legacy STA (STA3) may reject the TDLS discovery response frame due to the mismatch between the TA field and the TDLS responder STA address field of the link identifier element, and the legacy STA may not proceed to the TDLS setup stage.

[0134] FIG. 19 depicts a flowchart 1900 illustrating communication between a non-AP MLD1912 and a non-MLD STA (STA3) 1922 via a non-MLD AP1904 for multi-link peer-to-peer communication according to yet another embodiment of the present disclosure in accordance with Option 2 described above. The communication is divided into a discovery stage 1901, a setup stage 1902, and a direct link communication 1903. Different from all the embodiments shown in the present disclosure, it should be noted that for all address fields, especially the TDLS responder field represented by two addresses separated by dashes in FIG. 19 (e.g., A / B), either one of the two addresses (A or B) is used in the address field based on the knowledge of the legacy STA about the MAC address of the non-AP MLD. When the legacy STA identifies the non-AP MLD by its MLD MAC address, the MLD MAC address of the non-AP MLD is used; otherwise, the MAC address of the STA attached to the non-AP MLD operating on the same link as the legacy STA is used.

[0135] In discovery stage 1901, STA3 1922 can initiate TDLS discovery by transmitting a data frame 1932 containing a TDLS discovery request 1934 to non-AP MLD1 1912 via AP MLD1904. The data frame 1932 includes a DA field set to either the MLD MAC address of non-AP MLD1 (STA-ML1-M) or the MAC address of STA2 (STA2-M). The TDLS discovery request 1934 includes a TDLS initiator field set to the MAC address of STA3 (STA3-M), and a TDLS responder field set to either the MLD MAC address of non-AP MLD1 or the MAC address of STA2.

[0136] Upon receiving the data frame 1932, AP MLD1904 identifies, based on the MAC address in the DA field, that the TDLS discovery request 1934 contained in the data frame 1932 is addressed to either non-AP MLD or STA2, and transfers the data frame 1932' containing the TDLS discovery request 1934' received from STA3 1922 to STA1914 when the MAC address of STA2 is used, or to one of the associated STAs of non-AP MLD1 1912, e.g., STA1 1913 in this embodiment, when the MAC address of non-AP MLD is included, thus causing a crossover to Link 1. When transferring the data frame 1932' to STA1 1913, AP MLD1904 sets the MAC address of STA1 (STA1-M) in the RA field. Therefore, the data frame is correctly received by STA1 1913.

[0137] Upon receiving the TDLS discovery request 1934', non-AP MLD1912 can directly return a TDLS discovery response action frame 1942 to STA3 1922 on the link. In this case, even if a crossover has occurred, non-AP MLD1 sends the TDLS discovery response 1942 to the TDLS initiator STA3 1922 via a direct path on the correct link (Link 2) identified by the BSSID field using STA2 1914.

[0138] It is important that the non-AP MLD1912 sets the TA field of the TDLS discovery response action frame 1942 to be the same as that included in the TDLS responder field.

[0139] The non-AP MLD1912 also sets the RA field of the TDLS discovery response action frame 1942 to the MAC address of STA3 (STA3-M). Therefore, frames such as the TDLS discovery response action frame 1942 sent directly on the link from STA2 1914 to STA3 1922 will be correctly received via STA3 1922. The STA or MLD MAC address of the TA field of the TDLS discovery response action frame 1942 (similar to that included in the TDLS responder field) is also used to set the RA field of the data frame transmitted in the direct link communication 1903. Since the TA field and the TDLS responder field contain the same address (either the STA MAC address or the MLD MAC address), the TDLS responder frame is not rejected by STA3 1922.

[0140] In the subsequent setup stage 1902, STA3 1922 can initiate a TDLS setup with non-AP MLD1912 via AP MLD1904 by sending a further data frame 1952 including the TDLS setup request 1954 from STA3 1922 to non-AP MLD1912 via AP MLD1904. The data frame 1932 includes a DA field set to the MLD MAC address of non-AP MLD1 (STA-ML1-M). The TDLS setup request 1954 includes a TDLS initiator field set to the MAC address of STA3 (STA3-M), and a TDLS responder field set to either the MLD MAC address of non-AP MLD1 or the MAC address of STA2.

[0141] AP MLD1904 identifies that a further data frame 1952 is addressed to non-AP MLD1 1912 based on the MLD MAC address in the DA field, and transfers the further data frame 1952 to one of the associated STAs of non-AP MLD1 1912, for example STA2 1914 in this embodiment. When transferring the data frame 1952 to STA2 1914, AP MLD1904 also sets the RA field to the MAC address of STA2 (STA2-M). Therefore, the data frame 1952 is correctly received by STA2 1914.

[0142] Upon receiving the TDLS setup request 1954, non-AP MLD1912 may respond by returning another data frame 1962 including a TDLS setup response 1964 to STA3 1922, i.e., the TDLS initiator, via AP MLD1904. The data frame includes a DA field set to the MAC address of STA3 (STA3-M). The TDLS setup response 1964 includes a TDLS initiator field and a TDLS responder field, both set to the same MAC address as that of the TDLS setup request 1954.

[0143] Upon receiving the data frame 1962, AP MLD1904 identifies that the TDLS setup response 1964 included in the data frame 1962 is addressed to STA3 1922 based on the MAC address of STA3 in the DA field, and transfers the data frame 1962 to STA3 1922. When transferring the data frame 1962 to STA3 1922, AP MLD1904 also sets the RA field to the MAC address of STA3 (STA3-M). Therefore, the data frame is correctly received by STA3 1922.

[0144] Subsequently, STA3 1922 transmits a data frame 1972 including a TDLS setup confirmation 1974 to non-AP MLD1 1912 via AP MLD1904. The data frame 1972 includes a DA field set to the MAC address of non-AP MLD1 (STA-ML1-M). The TDLS setup confirmation 1974 includes a TDLS initiator field and a TDLS responder field, both set to the same MAC address as that of the TDLS setup request 1954.

[0145] Based on the MLD MAC address in the DA field, AP MLD1904 identifies that the data frame 1972 is addressed to non-AP MLD1 1912 and transfers the data frame 1972 to one of the associated STAs of non-AP MLD1, for example, STA2 1914 in this embodiment. When transferring the data frame 1972 to STA2 1914, AP MLD1904 also sets the RA field to the MAC address of STA2 (STA2-M). Thus, the data frame 1972 is correctly received by STA2 1914, and the setup phase is completed.

[0146] When the TDLS setup between non-AP MLD1 1912 and STA3 is completed, STA2 1914 of non-AP MLD1 and STA3 1922 can perform direct peer-to-peer communication with each other and transmit a data frame 1982 via a direct path on a common operating link (Link 2). The RA of such a data frame 1982 is set to the same MLD or STA MAC address as that of the TA field of the TDLS discovery response action frame 1942 (which is the same as that included in the TDLS responder field).

[0147] FIG. 20 depicts a flowchart 2000 that illustrates an address setting process of an MLD that is a TDLS response STA according to an embodiment of the present disclosure. In step 2002, a TDLS frame is received. In step 2004, it is determined whether the received TDLS frame is a TDLS discovery request frame or a TDLS setup frame, and whether the TDLS discovery request frame or the TDLS setup frame includes an ML indication. If Yes, step 2006 is performed; otherwise, step 2008 is performed. In step 2006, a step of setting the TA of a frame directly transmitted by the TDLS response STA, for example, a TDLS discovery response frame or a data frame, as the MAC address of the transmitting STA is performed. In step 2008, a step of setting the TA of a frame directly transmitted by the TDLS response STA to be the same as the address included in the TDLS responder STA address field of the link identifier element included in the TDLS frame is performed. The address setting process can then end after performing step 2006 or 2008. Alternatively, the TDLS response STA can always set the TA of a frame directly transmitted by the TDLS response STA to be the same as the address included in the TDLS responder STA address field of the link identifier element included in the TDLS frame.

[0148] According to an embodiment of the present disclosure, a security key (TPK) used to provide confidentiality and authentication of frames exchanged on all direct links is derived using a 3-way TDLS peer key (TPK) handshake protocol performed over the TLDS setup phase. FIG. 21 depicts a flowchart 2100 that illustrates communication between two non-AP MLDs 2112 and 2122 via a non-MLD AP 2104 for multi-link peer-to-peer communication according to an embodiment of the present disclosure. This embodiment illustrates a TPK setup phase 2102 and direct link communication 2103.

[0149] In the TPK setup stage 2102, the non-AP MLD1 2112 can start the TPK setup with the non-AP MLD2 2122 via the AP MLD2104 by sending a data frame 2132 containing a TDLS setup request (further including TDLS pairwise master key (PMK) handshake message 1) 2134 from the STA2 2114 to the non-AP MLD2 2122 via the AP MLD2104. The data frame 2132 includes a DA field set to the MLD MAC address (STA-ML2-M) of the non-AP MLD2. The TDLS setup request 2134 includes a link identifier element and a fast BSS transition element (FTE), and an ML element including information of one or more attached STAs operating on one or more links required for the non-AP MLD1 and ML-TDLS.

[0150] Based on the MAC address of the non-AP MLD2 in the DA field, the AP MLD2104 identifies that the data frame 2132 is addressed to its associated non-AP MLD2 2122, and transfers the data frame 2132 to one of the attached STAs of the non-AP MLD2, for example, STA3 2123 in this embodiment. The AP MLD2104 also sets the RA field to the MAC address (STA3-M) of the STA3 when transferring the data frame 2132 to the STA3 2123. Therefore, the data frame 2132 is correctly received by the STA3 2123.

[0151] Even if a crossover from link 2 to link 1 occurs, non-AP MLD2 2122 that receives the TDLS setup request 2134 may respond by sending back to non-AP MLD1 2112 via AP MLD2104 another data frame 2142 that includes a TDLS setup response (further including TDLS PMK handshake message 2) 2144. The TDLS setup response 2144 includes a DA field set to the MAC address of non-AP MLD1 (STA-ML1-M). The TDLS setup response 2144 includes a link identifier element and a fast BSS transition element (FTE), and an ML element that includes information with its attached STAs operating on one or more links agreed upon for non-AP MLD2 and ML-TDLS.

[0152] AP MLD2104 that receives the data frame 2142 identifies that the TDLS setup response 2144 included in the data frame 2142 is addressed to non-AP MLD1 2112, and transfers the data frame 2142 to one of the attached STAs of non-AP MLD1 2112, for example STA2 2114 in this embodiment. AP MLD2104 also sets the MAC address of STA2 (STA2-M) in the RA field when transferring the data frame 2142 to STA2 2114. Therefore, the data frame is correctly received by STA2 2114.

[0153] Subsequently, STA2 2114 sends a data frame 2152 that includes a TDLS setup confirmation (further including TDLS PMK handshake message 3) 2154 to non-AP MLD2 2122 via AP MLD2104. The data frame 2152 includes a DA field set to the MAC address of non-AP MLD2 (STA-ML2-M). The TDLS setup confirmation 2154 includes a link identifier element and a fast BSS transition element (FTE), and an ML element that includes information with its attached STAs operating on one or more links confirmed for non-AP MLD1 and ML-TDLS.

[0154] Based on the MAC address in the DA field, the AP MLD2104 identifies that the data frame 2152 is addressed to the non-AP MLD2 2122, and transfers the data frame 2152 to one of the associated STAs of the non-AP MLD2, for example, STA4 2124 in this embodiment. When transferring the data frame 2152 to the STA4 2124, the AP MLD2104 also sets the RA field to the MAC address of the STA4 (STA4-M). Therefore, the data frame 2152 is correctly received by the STA4 2124, and the setup phase is completed.

[0155] When the TDLS setup between the non-AP MLD1 2112 and the non-AP MLD2 2122 is completed, any two STAs from the non-AP MLD1 2112 and the non-AP MLD2 2122 can perform direct multi-link peer-to-peer communication with each other, and transmit data frames via a direct path in Link 1 and Link 2. For example, STA2 and STA4, as well as STA1 and STA3, can exchange data frames 2162 and 2172 via direct paths in both Link 2 and Link 1 respectively.

[0156] Figure 22A depicts an example format of the FTE2202. The FTE2202 includes an element ID field, a length field, a Message Integrity Code (MIC) control field, a MIC field, an ANonce field, and an SNonce field. The TPK derivation is shown in the following formula.

[0157] TPK-Key-Input = Hash(min(SNonce, ANonce)||max(SNonce, ANonce)) (Formula 1) TPK = KDF-Hash-Length(TPK-Key-Input, “TDLS PMK”, min(MAC_I, MAC_R)||max(MAC_I, MAC_R)||BSSID) (Formula 2) TPK-KCK = L(TPK, 0, 128) (Formula 3) TPK - TK = L(TPK, 128, length - 128) (Equation 4) Where BSSID, MAC_I, and MAC_R are the values of the BSSID, TDLS initiator STA address field, and TDLS responder STA address field of the link identifier element included in the TDLS setup frame, respectively. This is regardless of whether the link identifier element contains the MLD MAC address or the MAC address of the attached STA.

[0158] In one embodiment, a key confirmation key (KCK) is used to provide data origin authentication in TDLS setup response and TDLS setup confirmation frames, while the same TPK - TK is used to provide confidentiality for all protected frames transmitted on all direct links.

[0159] Figure 22B depicts an example format of the link identifier element 2222. The link identifier element 2222 includes an element ID field, a length field, a BSSID field, a TDLS initiator STA address field, and a TDLS responder STA address field.

[0160] During the calculation of the message integrity code (MIC) for TPK handshake messages 2 and 3, i.e., the setup response and setup confirmation, regardless of whether the link identifier element contains the MLD MAC address or the MAC address of the attached STA, the values of the TDLS initiator STA address field and the TDLS responder STA address field of the link identifier element included in the TDLS setup frame are used as the TDLS initiator STA MAC address and the TDLS responder STA MAC address, respectively. The MIC must be calculated for the concatenated values in the following order. · TDLS initiator STA MAC address (6 octets) ·TDLS Responder STA MAC address (6 octets) ·Transaction sequence number (1 octet) set to value 2 or 3 ·Link identifier element ·RSNE ·Timeout interval element ·FTE, the MIC field of FTE is set to 0 ·ML element (if the ML element is included in the TDLS setup frame)

[0161] What is important is that the ML element is included in the MIC calculation. In one embodiment, the above MIC calculation is performed using the TPK-KCK and AES-128-CMAC algorithms.

[0162] According to the present disclosure, in ML-TDLS direct link communication, the BlockAck agreement negotiated for a traffic identifier (TID) between two non-AP MLDS on any one direct link is applied to all direct links between the two non-AP MLDS. In other words, the common multi-link functions supported by both non-AP MLDS are available on all direct links, and such common multi-link functions include multi-link BlockAck, cross-link retransmission of frames, and MLD MAC address-based additional authentication data (AAD: Additional Authentication Data) and Nonce configuration during frame encapsulation or decapsulation under the counter mode (CCMP) or Galois / counter mode protocol (GCMP) by the cipher block chaining message authentication code protocol.

[0163] The same sequence number space and packet number (PN: Packet Number) space are used for frames of TIDs exchanged on any direct link. Retransmission of failed frames can also occur on any direct link. The same PN is used when a protected frame is retransmitted on another direct link.

[0164] Figure 23 depicts an example format of a data frame 2300 transmitted over a direct link between two non-AP MLDs. The data frame 2300 includes a frame control field, a duration field, an address 1 field, an address 2 field, an address 3 field, a sequence control field, a QoS control field, an HT control field, a payload field, and an FCS. The frame control field, the duration field, the address 1 field, the address 2 field, the address 3 field, the sequence control, the QoS control field, and the HT control field can be grouped as a MAC header, and the payload field is the frame body. The frame control field includes a To DS field and a From DS field, both of which are set to 0.

[0165] Figure 23B depicts an example configuration 2320 of an MLD MAC address-based AAD used for encapsulation or decapsulation of a frame under counter mode by CCMP or GCMP. The AAD includes a total of 30 octets. The AAD includes a frame control (FC:Frame Control) field (2 octets), an MLD-RA field (6 octets), an MLD-TA field (6 octets), an address 3 (A3:Address 3) field (6 octets), a sequence control (SC:Sequence Control) field (2 octets), an address 4 (A4) field (6 octets), and a QOS control (QC:QOS Control) field (2 octets). Importantly, the MLD MAC addresses of the receiving MLD and the transmitting MLD are used in the A1 and A2 fields of the AAD, respectively, rather than in the A1 and A2 fields of the frame.

[0166] Figure 23C depicts an example of the configuration 2340 of an MLD MAC address-based Nonce used for encapsulation or decapsulation of frames under CCMP counter mode or GCMP. The Nonce contains a total of 13 octets. The Nonce includes a Nonce flag (1 octet), an MLD-TA field (6 octets), and a PN field (6 octets). Importantly, the MLD MAC address of the transmitting MLD is used in the A2 field of the Nonce rather than in the A2 field of the frame.

[0167] The rules for ADD and Nonce calculation during CCMP / GCMP encapsulation / decapsulation of data frame 2300 exchanged directly between two non-AP MLDs over a link are as follows. a) The MLD MAC address of the recipient MLD is used as the A1 field for the construction of AAD. b) The MLD MAC address of the transmitting MLD is used as the A2 field for the construction of AAD and Nonce. c) If the non-AP MLD is related to an AP MLD, the MLD MAC address of the AP MLD is used as the A3 field for the construction of AAD. Otherwise, the address 3 field of the protected frame is used for A3.

[0168] Alternatively, the addresses contained in the TDLS initiator STA address field, TDLS responder address field, and BSSID field of the link identifier element included in the TDLS setup frame can be used instead in the construction of AAD and Nonce.

[0169] In one embodiment, multi-link functions such as ML-TDLS link switching are available. When a non-AP MLD instructs its peer non-AP MLD to support TDLS link switching by means of a TDLS link switching support field in which its peer MLD is set to, for example, "1" or "True", it may request to switch an existing direct link to another link. A TDLS channel switch request / response frame may be used for the purpose of TDLS link switching. The frame is encapsulated in a data frame and transmitted on the current direct link. Alternatively, a new frame, for example, a TDLS link switch request / response frame, may be defined for this purpose.

[0170] FIG. 24 depicts a flowchart 2400 illustrating multi-link peer-to-peer communication between two non-AP MLDs 2412 and 2422 associated with an AP MLD 2402 according to an embodiment of the present disclosure. Non-AP MLD1 2412 has set up a TDLS direct link with non-AP MLD2 2422 on link 1, and it is assumed that a data frame 2432 is transmitted on link 1 between the two non-AP MLDs 2412 and 2422. Non-AP MLD1 2412 may intend to switch its direct link (on link 1) with non-AP MLD2 2422 by transmitting a TDLS channel switch request 2442 to non-AP MLD2 2422 on the current direct link. In one embodiment, non-AP MLD1 2412 determines that non-AP MLD2 2422 supports TDLS link switching based on the indication of the TDLS link switching support field in the TDLS discovery response transmitted by non-AP MLD2 2422. Non-AP MLD2 2422 that receives such a request 2442 may respond by returning a TDLS channel switch response 2452 to non-AP MLD1 2412 on the current direct link.

[0171] In one case, if link switching is successful, after the switching time, the TDLS direct link is switched from link 1 to link 2, and the direct link on link 1 is invalidated. On the other hand, if link switching fails, the TDLS direct link between the two non-AP MLD2412 and 2422 remains on link 1.

[0172] Encapsulated data frames (e.g., Ethertype 89-0d data frames that accommodate the TDLS payload) can be used as TDLS channel switch request frames. FIG. 25 shows an example format of an Ethertype 89-0d data frame 2500 used to accommodate a TDLS channel switch request frame according to an embodiment of the present disclosure.

[0173] The Ethertype 89-0d data frame 2500 includes a frame control field, a duration field, an address 1 field, an address 2 field, an address 3 field, a sequence control field, a QoS control field, an HT control field, an LLC field, a SNAP field 2502, a payload type field 2504, a payload field 2506, and an FCS. The frame control field, the duration field, the address 1 field, the address 2 field, the address 3 field, the sequence control, the QOS control field, and the HT control field can be grouped as a MAC header, and the LLC field, the SNAP field 2502, the payload type field 2504, and the payload field 2506 can be grouped as a frame body. The SNAP field 2502 is set to the Ethertype of 89-0d, and the payload type field 2504 is set to correspond to TDLS. The payload field 2506 includes a category field 2508, a TDLS action field 2510, a target channel field, a link identifier element 2512, and an ML element 2514. The category field 2508 is set to correspond to TDLS. The TDLS action field 2510 is set to correspond to a TLDS channel switch request. The link identifier element 2512 indicates the current link. The ML element 2514 includes a multi-link control subfield including an element ID subfield, a length subfield, an element ID extension subfield, a type field 2516, and a presence bitmap field, a common information field 2518, and a link information field 2520.

[0174] The type field 2516 is set to support TDLS. The common information field 2518 includes an MLD MAC address subfield set to correspond to the MLD MAC address of the transmitting non-AP MLD. The link information field 2520 includes a link ID subfield, a link identifier element subfield 2522, and a capability / operation subfield. The link identifier element subfield 2522 indicates the target link to which the MLD attempts to switch. Alternatively, the link identifier element subfield 2522 may not exist, and the link ID field indicates the target link.

[0175] According to the present disclosure, a non-AP MLD may request an AP or an AP MLD to set up a quiet period (QTP) on multiple links via a single request on one link. FIG. 26 depicts a flowchart 2600 illustrating multi-link peer-to-peer communication between two non-AP MLDs 2612, 2622 associated with an AP / AP MLD 2602 according to an embodiment of the present disclosure. It is assumed that the non-AP MLD1 2612 has set up TDLS direct links with the non-AP MLD2 2622 on link 1 and link 2. The non-AP MLD1 2612 can request the AP / AP MLD 2602 to set up a quiet period (QTP) on link 1 and link 2 by transmitting a QTP request 2632 on link 1, and the QTP request 2632 includes an ML element. The ML element indicates an additional link (e.g., link 2) supported by the MLD.

[0176] The AP / AP MLD2602 that receives the QTP request 2632 can, in response, send a QTP response 2642 indicating that the QTP request was successful. Therefore, the QTP function is set up on Link 1 and Link 2. At the start of QTP, the AP / AP MLD2602 can send QTP setup frames 2662, 2664 on multiple links to protect the links for direct communication. Thereafter, the non-AP MLD1 2612 can send data frames 2672, 2674, 2682, 2684 in QTP2652 to the non-AP MLD2 2622 on both direct links, Link 1 and Link 2.

[0177] Figure 27 shows an example format of a Quiet Period (QTP) request / response frame 2700. The QTP request / response frame 2700 includes a Frame Control field, a Duration field, an Address 1 field, an Address 2 field, an Address 3 field, a Sequence Control field, an HT Control field, a Category field 2702, a HE Action field 2704, a QTP element, an ML element 2706, and an FCS. The Frame Control field, the Duration field, the Address 1 field, the Address 2 field, the Address 3 field, the Sequence Control, and the HT Control fields can be grouped as a MAC header, and the Category field 2702, the HE Action field 2704, the QTP element, and the ML element 2706 can be grouped as a frame body. The Category field 2702 is set to correspond to the HE Action. The HE Action field 2704 is set to correspond to QTP. The ML element 2706 includes a Multi-Link Control subfield that includes an Element ID subfield, a Length subfield, an Element ID Extension subfield, a Type field 2708 and an Existence Bitmap field, a Common Information field 2710, and one or more Link Information fields 2712.

[0178] The type field 2708 is set to support QTP. The common information field 2710 includes an MLD MAC address sub-field set to correspond to the MLD MAC address of the transmitting non-AP MLD. Each of the one or more link information fields 2712 includes a link ID sub-field and a QTP element 2714 that includes QTP parameters of another link identified by the link ID of the link ID sub-field.

[0179] According to the present disclosure, a non-AP MLD may request an AP MLD to set up a TDLS-Target Wake Time (TWT) Service Period (SP) for direct link communication on one or more links. FIG. 28 depicts a flowchart 2800 that illustrates multi-link peer-to-peer communication between two non-AP MLDs 2612, 2622 associated with an AP / AP MLD 2602 according to an embodiment of the present disclosure. It is assumed that non-AP MLD 1 2612 has set up direct links with non-AP MLD 2 2622 on link 1 and link 2. Non-AP MLD 1 2612 may request the AP / AP MLD 2602 to set up a TDLS-TWT SP on link 1 and link 2 by transmitting a TWT setup request 2832 on link 1, where the TWT setup request 2832 includes an ML element. The ML element indicates an additional link (e.g., link 2) supported by the MLD.

[0180] The AP / AP MLD 2602 that receives the TWT setup request 2832 may respond by returning a TWT setup response 2842 to the non-AP MLD 1 2612 indicating that the TWT setup request was successful. An unsolicited TWT setup response 2844 is also transmitted to another STA or MLD, e.g., non-AP MLD 2 2622, to request participation in the TWT SP on link 1 and link 2 for ML-TDLS. The TWT SP may be two separate TWT SPs on link 1 and link 2 with the same parameters (e.g., start time, duration, etc.).

[0181] Optionally, a restricted broadcast TWT SP is used to protect the TWT SP for ML-TDLS, and is overlaid on each individual TWT SP (by the AP / AP MLD) to prevent third-party STAs from transmitting between TDLS-TWT SPs. A restricted broadcast TWT SP refers to a broadcast TWT SP in which only the STAs that are members of that TWT SP are allowed to access the channel between TWT SPs, while all other STAs are not allowed to access the channel during this time. This is achieved by transmitting beacon frames 2852, 2854 that advertise the restricted broadcast TWT SP on each link. STAs other than the TDLS STA pair avoid accessing the channel during the restricted broadcast TWT SP.

[0182] When such a TWT SP is requested by a non-AP MLD, in this case non-AP MLD1 2612, at the start of the TWT SP for ML-TDLS within the broadcast-restricted TWT SP2862, the AP / AP MLD2702 can transmit a trigger frame 2872 for peer-to-peer (P2P) transmission directly to each of the direct links, i.e., link 1 and link 2. The trigger frame for P2P transmission can be based on the MU-RTS trigger frame defined in 11ax, or can be a new variant of the MU-RTS trigger frame defined by 11be. Thereafter, non-AP MLD1 2612 can transmit data frames 2882, 2884, 2892, 2894 to non-AP MLD2 2622 on both direct links, i.e., link 1 and link 2, within the TWT SP2874.

[0183] Figure 29 shows an example format of a Target Wake Time (TWT) setup frame 2900 and the TWT element 2906 of the TWT setup frame 2900. The TWT setup frame 2900 can be used in a TWT request or a TWT response and includes a frame control field, a duration field, an address 1 field, an address 2 field, an address 3 field, a sequence control field, an HT control field, a category field 2902, an action field 2904, a dialog token field, a TWT element 2906, an ML element 2908, and an FCS. The frame control field, the duration field, the address 1 field, the address 2 field, the address 3 field, the sequence control, and the HT control fields can be grouped as a MAC header, and the category field 2902, the action field 2904, the dialog token field, the TWT element 2906, and the ML element can be grouped as a frame body. The category field 2902 is set to correspond to a non-protected S1G action. The action field 2904 is set to correspond to a TWT setup. The ML element 2908 may include a TWT element for a TWT SP on another link.

[0184] The TWT element 2906 includes an element ID field, a length field, a control field 2910, and a TWT parameter information field 2912. The control field 2910 includes a negotiation type subfield, a TWT information frame invalid subfield, a wake period unit subfield, a multi-AP coordination TWT subfield, and a TDLS TWT2914 subfield. The TDLS TWT subfield 2914 is used to indicate a TWT SP for TDLS.

[0185] The TWT parameter information field 2912 includes a request type subfield including a trigger field 2916, a target wake time subfield, a nominal minimum TWT wake period subfield, a TWT wake interval exponent subfield, a TWT channel subfield, and a peer STA MAC address subfield 2918. The trigger field 2916 of the request type subfield includes a request to transmit a trigger frame on a direct link at the start of the TWT SP to provide a transmission opportunity for direct link communication from a non-AP MLD to an AP or an AP MLD. The peer STA MAC address field 2918 includes the MAC address of the TDLS peer STA.

[0186] This disclosure advantageously shows that the benefits of the TWT protocol are extended to direct link communication. The MAC address of the TDLS peer STA included in the peer STA MAC address field of the TWT setup request frame can be used by the AP to send an unsolicited TWT setup response frame to the peer STA to invite the peer STA to also participate in the same TWT SP. Alternatively, the peer STA can request a TWT SP from the AP.

[0187] In various embodiments, as previously described with respect to FIGS. 2A and 2B, the ML-TDLS discovery can also be performed by exchanging direct path access network query protocol (ANQP) request / response frames (a type of group address generic advertisement service (GAS) request / response frame). FIG. 30A shows an example format of an ANQP request frame 3000. The ANQP request frame 3000 includes a frame control field, a period field, an address 1 field, an address 2 field, an address 3 field, a sequence control field, an HT control field, a category field, a public action field 3002, a dialog token field, an advertisement protocol element 3004, a query request field 3006, and an FCS. The frame control field, the period field, the address 1 field, the address 2 field, the address 3 field, the sequence control and HT control fields can be grouped as a MAC header, and the category field, the public action field 3002, the dialog token field, the advertisement protocol element 3004 and the query request field 3006 can be grouped as a frame body. The public action field 3002 is set to correspond to a GAS request, and the advertisement protocol element 3004 is set to correspond to ANQP. The query request field 3006 includes the TDLS capability ANQP element detailed in FIG. 30C.

[0188] FIG. 30B shows an example format of the ANQP response frame 3020. The ANQP response frame 3020 includes a frame control field, a duration field, an address 1 field, an address 2 field, an address 3 field, a sequence control field, an HT control field, a category field, a public action field 3022, a dialog token field, a status code field, an advertisement protocol element 3024, a query response field 3026, and an FCS. The frame control field, the duration field, the address 1 field, the address 2 field, the address 3 field, the sequence control and HT control fields can be grouped as a MAC header, and the category field, the public action field 3022, the dialog token field, the status code field, the advertisement protocol element 3024 and the query response field 3026 can be grouped as a frame body. Similarly, the public action field 3022 is set to respond to a GAS request, and the advertisement protocol element 3024 is set to respond to ANQP. The query response field 3026 includes the TDLS capability ANQP element detailed in FIG. 30C.

[0189] FIG. 30C shows an example format of the TDLS capability ANQP element 3040. The TDLS capability ANQP element 3040 is included in the query request field 3006 and the query response field 3026, and includes information on the MLD and the supported direct link. The TDLS capability ANQP element 3040 includes an information ID field 3042, a length field, and a peer information field 3044. The information ID field 3042 is set to correspond to the TDLS capability. The peer information field 3044 includes a mode field, a BSSID field and a MAC field representing the BSSID and MAC address of the MLD operating on the link on which the ANQP frame is transmitted, a network information field 3046, an MLD information field 3048 including information about the MLD, and another link information field 3050 including information about other links of the MLD, such as the BSSID and MAC address of the STA operating on the link.

[0190] The network information field 3046 indicates whether the network is DHCP, IP or a network mask. The MLD information field 3048 includes a supported link count field and the MLD MAC address of the transmitting MLD. The TDLS capability ANQP element 3040 may include one or more other link information fields 3050 including information about links other than the link on which the ANQP response frame is transmitted. In one embodiment, the TDLS capability ANQP element 3040 does not include any other link information fields 3050 in the ANQP request frame. It is advantageous for the present disclosure to enable ML-TDLS discovery using ANQP and for the other link information field of the ANQP response frame to be able to include information about other links.

[0191] According to the present disclosure, when ML-TDLS discovery is initiated by transmitting a TDLS discovery request frame by a non-AP MLD (TDLS initiator), instead of including a TDLS ML element, the TDLS discovery request frame may include an indication for identifying that the transmitting STA belongs to the non-AP MLD, for example, a link identifier element. The non-AP MLD that receives the TDLS discovery request frame including the link identifier element can recognize that the TDLS initiator is an MLD and respond accordingly.

[0192] FIG. 31 shows an example format of a link identifier element 3100 included in a TDLS discovery request frame as an ML indication. The link identifier element 3100 includes an MLD information field including an element ID field, a length field, a BSSID field, a TDLS initiator STA address field, a TDLS responder STA address field, a supported link number field, and an MLD MAC field. Thereby, it is advantageous that the signaling overhead for ML-TDLS discovery using the TDLS discovery request frame is reduced.

[0193] FIG. 32 shows a configuration example of a communication device 3200 and two communication devices 3202 and 3204 attached to the communication device 3200. The communication device 3200 is implemented as a non-AP MLD, and each of the attached communication devices 3202 and 3204 can be implemented as a STA configured for multi-link peer-to-peer communication and multi-link TDLS discovery / setup according to various embodiments in the present disclosure. The communication device 3200 further includes a multi-link TDLS module 3212 configured to perform multi-link TDLS discovery / setup according to the above-described embodiments. The communication device 3200 further includes a MAC SAP 3210 used to communicate with the Internet layer and / or a Distribution Service (DS). Each of the communication devices 3202 and 3204 attached to the communication device provides a link 3226 and 3236 for association and can transmit / receive signals to / from other external communication devices / devices and / or DS. Each attached communication device 3202 and 3204 includes a MAC layer 3222 and 3232 and a PHY (physical) layer 3224 and 3234, and the PHY layer is connected to a wireless transmitter, a wireless receiver, and an antenna used to transmit / receive signals through the corresponding links 3226 and 3236 to / from other communication devices / devices. In one embodiment, the MAC layers 3222 and 3232 include a storage module that stores its STA MAC address and any STA MAC SAP for communicating directly with the Internet layer and / or DS for traffic with legacy STAs.

[0194] FIG. 33 shows a configuration example of a communication device 3300 and two communication devices 3302 and 3304 attached to the communication device 3300. The communication device 3300 is implemented as an AP MLD, and each of the attached communication devices 3302 and 3304 can be implemented as an AP configured for multi-link peer-to-peer communication and multi-link TDLS discovery / setup according to various embodiments in the present disclosure. The communication device 3300 includes an association record module 3316 that stores the MLD MAC address of each related non-AP MLD, the MAC address of the STA attached to each related MLD, the association ID (AID: Association ID) assigned to the non-AP MLD, and the like. The communication device 3300 receives a data frame from a related STA, determines that the destination address of the data frame is related to another related STA or MLD, transfers the data frame to another related STA or MLD accordingly, and further includes a data frame transfer module 3312 for setting the SA field of the frame to be transferred based on whether the receiving device is an MLD or a non-MLD STA. The communication device 3300 also includes an ML-QTP / ML-TWT processing module 3314 for setting up a QTP function (e.g., receiving a QTP request from a related STA and transmitting a QTP response and a QTP setup frame to the related STA) and a TWT function (e.g., receiving a TWT setup request from a related STA and transmitting a TWT setup response, a beacon frame, and a trigger frame to the related STA) on a direct link (single or plural) between related STAs and / or MLDs.

[0195] The communication device 3300 further includes a MAC SAP 3310 used to communicate with the Internet layer and / or the DS. The communication devices 3302, 3304 attached to the communication device each provide a link 3326, 3336 for association and can transmit / receive signals between other external communication devices / devices and / or the DS. Each attached communication device 3302, 3304 includes a MAC layer 3322, 3332 and a PHY (physical) layer 3324, 3334, and the PHY layer is connected to a wireless transmitter, a wireless receiver, and an antenna used to transmit / receive signals through the corresponding links 3326, 3336 between other communication devices / devices. In one embodiment, the MAC layer includes a storage module for storing its AP MAC address and any AP MAC SAP for communicating directly with the Internet layer for traffic between the legacy STA and the Internet layer.

[0196] The present disclosure can be implemented by software, hardware, or software cooperating with hardware. Each functional block used in the description of each of the above-described embodiments can be implemented, in part or in whole, by an LSI such as an integrated circuit, and each process described in each embodiment can be controlled, in part or in whole, by the same LSI or a combination of LSIs. The LSI can be formed individually as a chip, or one chip can be formed to include part or all of the functional blocks. The LSI can include a data input / output section coupled thereto. Here, the LSI can be referred to as an IC, a system LSI, a super LSI, or an ultra LSI depending on the difference in integration level. However, the technology for implementing the integrated circuit is not limited to the LSI and can be realized by using an application specific circuit, a general-purpose processor, or a dedicated processor. In addition, an FPGA (Field Programmable Gate Array) that can be programmed after the manufacture of the LSI, or a reconfigurable processor in which the connection and setting of circuit cells arranged inside the LSI can be reconfigured can be used. The present disclosure can be realized as digital processing or analog processing. If future integrated circuit technology replaces the LSI as a result of the progress of semiconductor technology or another derivative technology, the functional blocks can be integrated using the future integrated circuit technology. Biotechnology can also be applied.

[0197] The present disclosure can be implemented by any type of device, apparatus, or system having a communication function referred to as a communication device.

[0198] Some non-limiting examples of such communication devices include telephones (e.g., cellular (mobile) phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, netbooks), cameras (e.g., digital still / video cameras), digital players (digital audio / video players), wearable devices (e.g., wearable cameras, smartwatches, tracking devices), game consoles, digital book readers, telehealth / telemedicine (remote health and medical) devices, and vehicles that provide communication capabilities (e.g., automobiles, airplanes, ships), as well as various combinations thereof.

[0199] The communication device is not limited to being portable or mobile and may also include any type of non-portable or stationary device, apparatus, or system such as smart home devices (e.g., appliances, lighting, smart meters, control panels), vending machines, and any other "things" within the network of the "Internet of Things (IoT)".

[0200] Communication may include data exchange through, for example, cellular systems, wireless LAN systems, satellite systems, etc., and various combinations thereof.

[0201] The communication device may include devices such as a controller or sensor connected to a communication device that performs the communication functions described in the present disclosure. For example, the communication device may include a controller or sensor that generates a control signal or data signal used by a communication device that performs the communication function of the communication device.

[0202] The communication device may also include infrastructure facilities such as base stations, access points, and any other device, apparatus, or system that communicates with or controls the devices such as those in the above non-limiting examples.

[0203] Non-limiting examples of stations can be included in a first plurality of stations attached to a multiline station logical entity (i.e., such as an MLD), and as part of the first plurality of stations attached to the multiline station logical entity, the stations among the first plurality of stations share a common media access control (MAC) data service interface to an upper layer, and the common MAC data service interface is related to a common MAC address or a traffic identifier (TID).

[0204] Therefore, it can be seen that embodiments of the present invention provide a communication device and method for operation on multiple links in order to fully realize the improvement of throughput in multiline communication, particularly in multiline guaranteed retransmission.

[0205] The following examples are described in this disclosure.

[0206] 1. A communication device among a plurality of communication devices attached to a first multiline device (MLD), wherein the plurality of communication devices each operate on a corresponding link of the first MLD, and the communication device includes: A circuit that generates a request frame during operation, where the request frame is one of a discovery request frame for discovering the peer-to-peer communication capabilities of another communication device or a setup request frame for requesting the setup of one or more direct links, and the request frame includes a multiline (ML) indication that identifies that the communication device is attached to the first MLD; A transmitter that transmits the request frame on one link during operation; A communication device including the above.

[0207] 2. The request frame is one of a tunnel direct link setup (TDLS) discovery request frame, a TDLS setup request frame, and an access network query protocol (ANQP) request frame. The communication device according to Example 1. The communication device described in Example 1.

[0208] 3. The ML indication is an ML element, and the ML element is a communication device described in Example 1 that includes information about the first MLD and information about at least one other link supported by the first MLD.

[0209] 4. The ML indication is included corresponding to one of the link identifier element of the TDLS discovery request frame and the TDLS capability ANQP element of the ANQP request frame, which is a communication device described in Example 2.

[0210] 5. A receiver that receives a TDLS discovery response frame including an ML element from another communication device during operation, where the ML element includes information about the second MLD to which the other communication device belongs and information about at least one other link supported by the second MLD, which is further included in the communication device described in Example 1.

[0211] 6. A receiver that receives an ANQP response frame including an ML field from another communication device during operation, where the ML field includes information about the second MLD to which the other communication device belongs and information about at least one other link supported by the second MLD, which is further included in the communication device described in Example 1.

[0212] 7. The circuit is further configured to generate at least one of a TDLS setup request frame and a TDLS setup confirmation frame, where at least one of the TDLS setup request frame and the TDLS setup confirmation frame includes an ML element, the ML element includes information about the first MLD and information about at least one other link supported by the first MLD, and the transmitter further transmits at least one of the TDLS setup request frame and the TDLS setup confirmation frame to the second MLD to which the other communication device belongs. which is a communication device described in Example 1.

[0213] 8. A receiver that receives a TDLS setup response frame including an ML element from another communication device during operation, where the ML element includes information about a second MLD to which the other communication device belongs and information about at least one other link supported by the second MLD, the receiver, The communication device according to Example 1, further comprising.

[0214] 9. In response to the exchange of TDLS setup request frames, TDLS setup response frames, and TDLS setup confirmation frames, the circuit Sets up one or more direct links between the first MLD and the second MLD. The communication device according to Example 7 or 8, further configured to.

[0215] 10. At least one of the TDLS setup request frame, TDLS setup response frame, and TDLS setup confirmation frame includes a TDLS peer key (TPK) handshake message, and the circuit Generates a TPK for encrypting one or more frames transmitted on one or more direct links and / or decrypting one or more frames received on one or more direct links. The communication device according to Example 9, further configured to.

[0216] 11. At least one of the TDLS setup request frame, TDLS setup response frame, and TDLS setup confirmation frame each includes a corresponding ML element, and the circuit Calculates a message integrity code for each of the TDLS setup response frame and TDLS setup confirmation frame based on the corresponding ML element. The communication device according to Example 10, further configured to.

[0217] 12. The general multi-link functionality supported by the first MLD and the second MLD is available on one or more direct links, and the general multi-link functionality includes multi-link block ack, cross-link retransmission of frames, and MLD MAC address-based additional authentication data and Nonce configuration during encapsulation or decapsulation of frames under Counter Mode with Cipher Block Chaining Message Authentication Code Protocol (CCMP) or Galois / Counter Mode Protocol (GCMP). The communication device according to Example 9.

[0218] 13. The circuit is further configured to generate a TDLS channel switch request frame for switching from one of the one or more direct links to another, the TDLS channel switch request frame includes an ML element, the ML element includes information of another one of the one or more direct links, and the transmitter further transmits the TDLS channel switch request frame to the second MLD. The communication device according to Example 9.

[0219] 14. The circuit is further configured to generate a Quiet Period (QTP) request frame for setting up a quiet period on at least one of the one or more direct links, the QTP request frame includes an ML element, the ML element includes information of at least one of the one or more direct links, and the transmitter further transmits the QTP request frame to the Access Point Multi-Link Device (AP MLD) associated with the first MLD. The communication device according to Example 9.

[0220] 15. A receiver that receives a request frame from another communication device during operation, the request frame is one of a discovery request frame for discovering the peer-to-peer communication capability of the communication device or a setup request frame for requesting setup of one or more direct links, and the circuit Determine whether the received request frame includes an ML indication that identifies that another communication device is attached to the second MLD, In response to determining that the received request frame includes an ML indication that identifies that another communication device is attached to the second MLD, set the transmitter address (TA) field of the frame transmitted on one of the one or more direct links to the address included in the TDLS responder station (STA) address field of the link identifier element of the received request frame, In response to determining that the received request frame does not include an ML indication that identifies that another communication device is attached to the second MLD, set the TA field of the frame transmitted on one of the one or more direct links to the media access control (MAC) address of the communication device attached to the second MLD that transmits the frame on one of the one or more direct links, A receiver, further configured as described above, The communication device according to Example 1, further including

[0221] 16. The circuit is further configured to generate a target wake time (TWT) setup request frame for setting up a TWT service period (SP) on at least one of the one or more direct links, the TWT setup request frame includes a TWT element that includes information on the TWT SP for at least one of the one or more direct links, and the transmitter further transmits the TWT setup request frame to the AP MLD associated with the first MLD, The communication device according to Example 9.

[0222] 17. The TWT setup request frame includes an ML element, and the ML element includes information on at least one of the one or more links. The communication device according to Example 16.

[0223] 18. The circuit is When another communication device is not attached to the second MLD, set the transmitter address field of the TDLS discovery request frame to the MAC address of the communication device is further configured as the communication device according to Embodiment 2.

[0224] 19. An access point (AP) among a plurality of APs attached to an AP MLD, wherein the plurality of APs each operate in a corresponding link of the AP MLD, and the AP is, a receiver that, during operation, receives, in one link, a data frame in which a destination address (DA) field is set to another related communication device not attached to the MLD from a related communication device attached to the MLD; a circuit that, during operation, sets the source address (SA) field of the data frame as the MAC address of the related communication device; a transmitter that, during operation, transmits the data frame to another related communication device; An access point (AP) including

[0225] 20. A step of generating a request frame, wherein the request frame is one of a discovery request frame for discovering the peer-to-peer communication capability of a communication device or a setup request frame for requesting setup of one or more direct links, and the request frame includes an ML indication for identifying that another communication device transmitting the request frame is attached to the MLD, the step; A step of transmitting the request frame in one link; A communication method including

[0226] While the foregoing detailed description of embodiments of the present invention has presented exemplary embodiments, it must be recognized that there are a vast number of variations. It must further be recognized that the exemplary embodiments are examples and are not intended to limit the scope, applicability, operation, or configuration of the present 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, but various changes can be made to the functions and arrangements of the steps described in the exemplary embodiments, as well as the methods of operation and the modules and structures of the devices described in the exemplary embodiments, without departing from the scope of the subject matter described in the appended claims.

Claims

1. A first non-access point (non-AP) multi-link device (MLD) having a plurality of attached stations (STAs) operating on different links, a receiver for receiving a Tunnel Direct Link Setup (TDLS) setup request frame from a second non-AP MLD through an Access Point (AP) or AP MLD to set up a direct link connection on one or more links, the TDLS setup request frame including a first TDLS multi-link element including first MLD MAC address information indicating the first non-AP MLD; a transmitter for transmitting a TDLS setup response frame including information of the one or more links to the second non-AP MLD via the AP or the AP MLD when a direct link connection is agreed upon for the one or more links; A first non-AP MLD including:

2. The first TDLS multilink element includes a type field indicating TDLS and a common information field including the MLD MAC address information. The first non-AP MLD of claim 1 .

3. Prior to receiving the TDLS setup request frame, The receiver receives a TDLS discovery request frame from the AP or a second non-AP MLD via the AP MLD; The transmitter transmits a TDLS discovery response frame to a second non-AP MLD on a direct link. The first non-AP MLD of claim 1 .

4. the TDLS discovery request frame includes a link identifier element including a BSSID subfield; The first non-AP MLD according to claim 3 .

5. the TDLS discovery request frame includes a second TDLS multilink element including second MLD MAC address information; The first non-AP MLD according to claim 3 .

6. the TDLS setup request frame includes a first TDLS PMK handshake message; the TDLS setup response frame includes a second TDLS PMK handshake message; The receiving unit receives a TDLS setup confirmation frame including a third TDLS PMK handshake message through the AP or the AP MLD. The first non-AP MLD of claim 1 .

7. The TDLS setup request frame includes an RSNE, a timeout interval element, and a fast BSS transition element (FTE). The first non-AP MLD of claim 1 .

8. the receiving unit receiving a request frame indicating a quiet period for protecting direct communications on a direct link; The first non-AP MLD of claim 1 .

9. 1. A communication method for a first non-access point (non-AP) multi-link device (MLD) having a plurality of attached stations (STAs) operating on different links, comprising: receiving a tunnel direct link setup (TDLS) setup request frame from a second non-AP MLD through an access point (AP) or AP MLD for setting up a direct link connection on one or more links, the TDLS setup request frame including a first TDLS multi-link element including first MLD MAC address information indicating the first non-AP MLD; If a direct link connection is agreed upon for the one or more links, a TDLS setup response frame including information of the one or more links is sent to the second non-AP MLD via the AP or the AP MLD; Communication methods.

10. The first TDLS multilink element includes a type field indicating TDLS and a common information field including the MLD MAC address information. The communication method according to claim 9.

11. Prior to receiving the TDLS setup request frame, receiving a TDLS discovery request frame from the AP or a second non-AP MLD through the AP MLD; sending a TDLS discovery response frame on the direct link to the second non-AP MLD; The communication method according to claim 9.

12. the TDLS discovery request frame includes a link identifier element including a BSSID subfield; The communication method according to claim 11.

13. the TDLS discovery request frame includes a second TDLS multilink element including second MLD MAC address information; The communication method according to claim 11.

14. the TDLS setup request frame includes a first TDLS PMK handshake message; the TDLS setup response frame includes a second TDLS PMK handshake message; receiving, via the AP or the AP MLD, a TDLS setup confirmation frame including a third TDLS PMK handshake message; The communication method according to claim 9.

15. The TDLS setup request frame includes an RSNE, a timeout interval element, and a fast BSS transition element (FTE). The communication method according to claim 9.

16. receiving a request frame indicating a quiet period for protecting direct communications on the direct link; The communication method according to claim 9.

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