Link deletion for seamless roaming in wlans

Abstract

Methods and apparatuses for link deletion for seamless roaming in wireless local area networks (WLANs). A method of wireless communication performed by a first access point (AP) multi-link device (MLD) of a seamless mobility domain comprises receiving, from a non-AP MLD that is associated with the first AP MLD and that has links setup with the first AP MLD, a roam request message to roam from the first AP MLD to a second AP MLD of the seamless mobility domain. The method includes transmitting data to the non-AP MLD for a duration of time after a roam execution completion, and performing a link deletion procedure for deleting the links setup between the non-AP MLD and the first AP MLD.

Description

LINK DELETION FOR SEAMLESS ROAMING IN WLANS

[0001] The disclosure relates generally to wireless communication. More specifically, the disclosure relates to link deletion for seamless roaming in wireless local area networks (WLANs).

[0002] Wireless local area network (WLAN) technology allows devices to access the internet in the 2.4 GHz, 5GHz, 6GHz or 60 GHz frequency bands. WLANs are based on the Institute of Electrical and Electronic Engineers (IEEE) 802.11 standards. IEEE 802.11 family of standards aim to increase speed and reliability and to extend the operating range of wireless networks.

[0003] The demand of wireless data traffic is rapidly increasing due to the growing popularity among consumers and businesses of smart phones and other mobile data devices, such as tablets, "note pad" computers, net books, eBook readers, and machine type of devices. In order to address the issue of increasing bandwidth requirements that are demanded for wireless communications systems, different schemes are being developed to allow multiple user terminals to communicate with a single access point by sharing the channel resources while achieving high data throughputs. multiple input multiple output (MIMO) technology represents one such approach that has emerged as a popular technique. MIMO has been adopted in several wireless communications standards such 802.11ac, 802.11ax, etc.

[0004] The above information is presented as background information only to assist with an understanding of the disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the disclosure.

[0005] Aspects of the disclosure are to address at least the above-mentioned problems and / or disadvantages and to provide at least the advantages described below.

[0006] Embodiments of the disclosure provide methods and apparatuses for link deletion for seamless roaming in WLANs.

[0007] In an embodiment, a method of wireless communication performed by a first access point (AP) multi-link device (AP MLD) of a seamless mobility domain comprises receiving, from a non-AP MLD that is associated with the first AP MLD and that has links setup with the first AP MLD, a roam request message for roaming from the first AP MLD to a second AP MLD of the seamless mobility domain. The method includes transmitting data to the non-AP MLD for a duration of time after a roam execution completion, and performing a link deletion procedure for deleting the links setup between the non-AP MLD and the first AP MLD.

[0008] In an embodiment, a method performed by a non-AP MLD of a seamless mobility domain comprises transmitting, to a first AP MLD that is associated with the non-AP MLD and that has links setup with the non-AP MLD, a roam request message for roaming from the first AP MLD to a second AP MLD of the seamless mobility domain. The method includes receiving data from the first AP MLD for a duration of time after a roam execution completion, and performing a link deletion procedure for deleting the links setup between the non-AP MLD and the first AP MLD.

[0009] In an embodiment, an electronic device comprises at least one processor including processing circuitry, and memory storing instructions, where the instructions, when executed by the at least one processor individually or collectively, cause the electronic device to: receive, from a non-AP MLD that is associated with the first AP MLD and that has links setup with the first AP MLD, a roam request message for roaming from the first AP MLD to a second AP MLD of the seamless mobility domain; transmit data to the non-AP MLD for a duration of time after a roam execution completion; and perform a link deletion procedure for deleting the links setup between the non-AP MLD and the first AP MLD.

[0010] Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses various embodiments of the disclosure.

[0011] The above and other aspects, features, and advantages certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0012] FIG. 1 illustrates an example wireless network according to various embodiments of the disclosure;

[0013] FIG. 2a illustrates an example access point (AP) according to various embodiments of the disclosure;

[0014] FIG. 2b illustrates an example station (STA) according to various embodiments of the disclosure;

[0015] FIG. 3 illustrates an example of link reconfiguration for adding and deleting links according to various embodiments of the disclosure;

[0016] FIG. 4 illustrates an example procedure for timeout based link deletion according to various embodiments of the disclosure;

[0017] FIG. 5 illustrates an example procedure for timeout value advertisement by the AP MLD according to various embodiments of the disclosure;

[0018] FIG. 6 illustrates an example procedure for timeout value in a response message by the AP MLD according to various embodiments of the disclosure;

[0019] FIG. 7 illustrates an example control field format for the reconfiguration multi-link element according to various embodiments of the disclosure;

[0020] FIG. 8 illustrates an example STA information field format for the reconfiguration multi-link element according to various embodiments of the disclosure;

[0021] FIG. 9 illustrates an example non-AP side procedure for link deletion according to various embodiments of the disclosure;

[0022] FIG. 10 illustrates an example procedure for transmitting a link deletion message to the new AP according to various embodiments of the disclosure;

[0023] FIG. 11 illustrates an example procedure for transmitting a link deletion message to the old AP according to various embodiments of the disclosure;

[0024] FIG. 12 illustrates an example AP side procedure for link deletion according to various embodiments of the disclosure;

[0025] FIG. 13 illustrates an example procedure for transmitting a link deletion message through the new AP MLD according to various embodiments of the disclosure;

[0026] FIG. 14 illustrates an example procedure for transmitting a link deletion message to through the old AP MLD according to various embodiments of the disclosure;

[0027] FIG. 15 illustrates an example procedure for non-AP side inference of completion of buffer on the AP MLD side according to various embodiments of the disclosure; and

[0028] FIG. 16 illustrates an example method performed by a first AP MLD in a wireless communication system according to various embodiments of the disclosure.

[0029] Throughout the drawings, it should be note that like reference numbers are used to depict the same or similar features, and structures.

[0030] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding, but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

[0031] The term "couple" and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with one another. The terms "transmit," "receive," and "communicate," as well as derivatives thereof, encompass both direct and indirect communication. The terms "include" and "comprise," as well as derivatives thereof, mean inclusion without limitation. The term "or" is inclusive, meaning and / or. The phrase "associated with," as well as derivatives thereof, means to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, have a relationship to or with, or the like. The term "controller" means any device, system or part thereof that controls at least one operation. Such a controller may be implemented in hardware or a combination of hardware and software and / or firmware. The functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. The phrase "at least one of," when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one item in the list may be needed. For example, "at least one of: A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C.

[0032] Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code and embodied in a computer readable medium. The terms "application" and "program" refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer readable program code. The phrase "computer readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer readable medium" includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A "non-transitory" computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer readable medium includes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device.

[0033] At least part of the functions in a device or electronic apparatus provided in an embodiment of the disclosure may be implemented through an artificial intelligence (AI) model, such as, at least one of a plurality of modules of the device or electronic apparatus may be implemented through the AI model. A function associated with AI may be performed through the non-volatile memory, the volatile memory, and the processor.

[0034] It should be appreciated that the blocks in each flowchart and combinations of the flowcharts may be performed by one or more computer programs which include instructions. The entirety of the one or more computer programs may be stored in a single memory device or the one or more computer programs may be divided with different portions stored in different multiple memory devices.

[0035] Any of the functions or operations described herein can be processed by one processor or a combination of processors. The one processor or the combination of processors is circuitry performing processing and includes circuitry like an application processor (AP, e.g. a central processing unit (CPU)), a communication processor (CP, e.g., a modem), a graphics processing unit (GPU), a neural processing unit (NPU) (e.g., an artificial intelligence (AI) chip), a wireless fidelity (Wi-Fi) chip, a Bluetooth®chip, a global positioning system (GPS) chip, a near field communication (NFC) chip, connectivity chips, a sensor controller, a touch controller, a finger-print sensor controller, a display driver integrated circuit (IC), an audio CODEC chip, a universal serial bus (USB) controller, a camera controller, an image processing IC, a microprocessor unit (MPU), a system on chip (SoC), an IC, or the like.

[0036] Definitions for other certain words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many if not most instances, such definitions apply to prior as well as future uses of such defined words and phrases.

[0037] FIGS. 1 through 16, discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged system or device.

[0038] Existing WLAN standards support multiple bands of operation, where an access point (AP) and a non-AP device may communicate with each other, called links. Thus, both the AP and non-AP device may be capable of communicating on different bands / links, which is referred to as mutli-link operation (MLO). Devices capable of such MLO are referred to as multi-link devices (MLDs).

[0039] The following documents and standards descriptions are hereby incorporated by reference into the disclosure as if fully set forth herein: IEEE P802.11be / D7.0, 2024; IEEE Std 802.11-2020.

[0040] FIG. 1 illustrates an example wireless network 100 according to various embodiments of the disclosure. The embodiment of the wireless network 100 shown in FIG. 1 is for illustration only. Other embodiments of the wireless network 100 could be used without departing from the scope of the disclosure.

[0041] Referring to FIG. 1, the wireless network 100 may include APs 101 and 103. The APs 101 and 103 may communicate with at least one network 130, such as the internet, a proprietary internet protocol (IP) network, or other data network. The AP 101 may provide wireless access to the network 130 for a plurality of stations (STAs) 111-114 within a coverage area 120 of the AP 101. The APs 101-103 may communicate with each other and with the STAs 111-114 using Wi-Fi or other WLAN communication techniques.

[0042] Depending on the network type, other well-known terms may be used instead of "access point" or "AP," such as "router" or "gateway." For the sake of convenience, the term "AP" is used in this disclosure to refer to network infrastructure components that provide wireless access to remote terminals. In WLAN, given that the AP also contends for the wireless channel, the AP may also be referred to as a STA (e.g., an AP STA). Also, depending on the network type, other well-known terms may be used instead of "station" or "STA," such as "mobile station," "subscriber station," "remote terminal," "user equipment," "wireless terminal," or "user device." For the sake of convenience, the terms "station" and "STA" are used in this disclosure to refer to remote wireless equipment that wirelessly accesses an AP or contends for a wireless channel in a WLAN, whether the STA is a mobile device (such as a mobile telephone or smartphone) or is normally considered a stationary device (such as a desktop computer, AP, media player, stationary sensor, television, etc.). This type of STA may also be referred to as a non-AP STA.

[0043] In various embodiments of the disclosure, each of the APs 101 and 103 and each of the STAs 111-114 may be an MLD. In various embodiments, APs 101 and 103 may be AP MLDs, and STAs 111-114 may be non-AP MLDs. Each MLD may be affiliated with more than one STA. For convenience of explanation, an AP MLD is described herein as affiliated with more than one AP (e.g., more than one AP STA), and a non-AP MLD is described herein as affiliated with more than one STA (e.g., more than one non-AP STA).

[0044] Dotted lines show the approximate extents of the coverage areas 120 and 125, which are shown as approximately circular for the purposes of illustration and explanation only. It should be clearly understood that the coverage areas associated with APs, such as the coverage areas 120 and 125, may have other shapes, including irregular shapes, depending upon the configuration of the APs and variations in the radio environment associated with natural and man-made obstructions.

[0045] As described in more detail below, one or more of the APs may include circuitry and / or programming for facilitating link deletion for seamless roaming. Although FIG. 1 illustrates an example of a wireless network 100, various changes may be made to FIG. 1. For example, the wireless network 100 may include any number of APs and any number of STAs in any suitable arrangement. Also, the AP 101 may communicate directly with any number of STAs and provide those STAs with wireless broadband access to the network 130. Similarly, each AP 101-103 may communicate directly with the network 130 and provide STAs with direct wireless broadband access to the network 130. Further, the APs 101 and / or 103 may provide access to other or additional external networks, such as external telephone networks or other types of data networks.

[0046] FIG. 2a illustrates an example AP 101 according to various embodiments of the disclosure. The embodiment of the AP 101 illustrated in FIG. 2a is for illustration only, and the AP 103 of FIG. 1 may have the same or similar configuration. In various embodiments discussed below, the AP 101 may be an AP MLD. However, APs may come in a wide variety of configurations, and FIG. 2a does not limit the scope of this disclosure to any particular implementation of an AP.

[0047] Referring to FIG. 2a, the AP MLD 101 may be affiliated with multiple APs 202a-202n (which may be referred to, for example, as AP1-APn). Each of the affiliated APs 202a-202n may include multiple antennas 204a-204n, multiple RF transceivers 209a-209n, transmit (TX) processing circuitry 214, and receive (RX) processing circuitry 219. The AP MLD 101 may also include a controller / processor (e.g., including processing circuitry) 224, memory 229, and a backhaul or network interface 234.

[0048] The illustrated components of each affiliated AP 202a-202n may represent a physical (PHY) layer and a lower media access control (LMAC) layer in the open systems interconnection (OSI) networking model. In various embodiments, the illustrated components of the AP MLD 101 may represent a single upper MAC (UMAC) layer and other higher layers in the OSI model, which are shared by all of the affiliated APs 202a-202n.

[0049] For each affiliated AP 202a-202n, the RF transceivers 209a-209n may receive, from the antennas 204a-204n, incoming RF signals, such as signals transmitted by STAs in the network 100. In various embodiments, each affiliated AP 202a-202n may operate at a different bandwidth,e.g., 2.4 GHz, 5 GHz, or 6 GHz, and accordingly the incoming RF signals received by each affiliated AP may be at a different frequency of RF. The RF transceivers 209a-209n may down-convert the incoming RF signals to generate IF or baseband signals. The IF or baseband signals may be sent to the RX processing circuitry 219, which generates processed baseband signals by filtering, decoding, and / or digitizing the baseband or IF signals. The RX processing circuitry 219 may transmit the processed baseband signals to the controller / processor 224 for further processing.

[0050] For each affiliated AP 202a-202n, the TX processing circuitry 214 may receive analog or digital data (such as voice data, web data, e-mail, or interactive video game data) from the controller / processor 224. The TX processing circuitry 214 may encode, multiplexe, and / or digitize the outgoing baseband data to generate processed baseband or IF signals. The RF transceivers 209a-209n may receive the outgoing processed baseband or IF signals from the TX processing circuitry 214 and up-convert the baseband or IF signals to RF signals that are transmitted via the antennas 204a-204n. In various embodiments, each affiliated AP 202a-202n may operate at a different bandwidth,e.g., 2.4 GHz, 5 GHz, or 6 GHz, the outgoing RF signals transmitted by each affiliated AP may be at a different frequency of RF.

[0051] The controller / processor 224 may include one or more processors or other processing devices that control the overall operation of the AP MLD 101. For example, the controller / processor 224 may control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceivers 209a-209n, the RX processing circuitry 219, and the TX processing circuitry 214 in accordance with well-known principles. The controller / processor 224 may support additional functions as well, such as more advanced wireless communication functions. For instance, the controller / processor 224 may support beam forming or directional routing operations in which outgoing signals from multiple antennas 204a-204n are weighted differently to effectively steer the outgoing signals in a desired direction. The controller / processor 224 may also support orthogonal frequency division multiple access (OFDMA) operations in which outgoing signals are assigned to different subsets of subcarriers for different recipients (e.g., different STAs 111-114). Any of a wide variety of other functions may be supported in the AP MLD 101 by the controller / processor 224 including DL data handling in seamless roaming in WLANs. In some embodiments, the controller / processor 224 includes at least one microprocessor or microcontroller. The controller / processor 224 may be also capable of executing programs and other processes resident in the memory 229, such as an OS. The controller / processor 224 may move data into or out of the memory 229 as required by an executing process.

[0052] The controller / processor 224 may also coupled to the backhaul or network interface 234. The backhaul or network interface 234 may allow the AP MLD 101 to communicate with other devices or systems over a backhaul connection or over a network. The interface 234 may support communications over any suitable wired or wireless connection(s). For example, the interface 234 may allow the AP MLD 101 to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (such as the internet). The interface 234 may include any suitable structure supporting communications over a wired or wireless connection, such as an ethernet or RF transceiver. The controller / processor 224 may include various processing circuitry and / or multiple processors. For example, as used herein, including the claims, the term "processor" may include various processing circuitry, including at least one processor, wherein one or more of at least one processor, individually and / or collectively in a distributed manner, may be configured to perform various functions described herein. As used herein, when "a processor", "at least one processor", and "one or more processors" are described as being configured to perform numerous functions, these terms cover situations, for example and without limitation, in which one processor performs some of recited functions and another processor(s) performs other of recited functions, and also situations in which a single processor may perform all recited functions. Additionally, the at least one processor may include a combination of processors performing various of the recited / disclosed functions, e.g., in a distributed manner. At least one processor may execute program instructions to achieve or perform various functions.

[0053] The memory 229 may be coupled to the controller / processor 224. Part of the memory 229 may include a RAM, and another part of the memory 229 could include a Flash memory or other ROM.

[0054] As described in more detail below, the AP MLD 101 may include circuitry and / or programming for facilitating link deletion for seamless roaming. Although FIG. 2a illustrates one example of AP MLD 101, various changes may be made to FIG. 2a. For example, the AP MLD 101 may include any number of each component shown in FIG. 2a. As a particular example, an AP MLD 101 may include a number of interfaces 234, and the controller / processor 224 may support routing functions to route data between different network addresses. As an example embodiment, while each affiliated AP 202a-202n is shown as including a single instance of TX processing circuitry 214 and a single instance of RX processing circuitry 219, the AP MLD 101 may include multiple instances of each (such as one per RF transceiver) in one or more of the affiliated APs 202a-202n. Alternatively, only one antenna and RF transceiver path may be included in one or more of the affiliated APs 202a-202n, such as in legacy APs. Also, various components in FIG. 2a could be combined, further subdivided, or omitted and additional components could be added according to particular needs.

[0055] FIG. 2b illustrates an example STA 111 according to various embodiments of the disclosure. The embodiment of the STA 111 illustrated in FIG. 2b is for illustration only, and the STAs 111-115 of FIG. 1 could have the same or similar configuration. In various embodiments discussed below, the STA 111 is a non-AP MLD. However, STAs come in a wide variety of configurations, and FIG. 2b does not limit the scope of this disclosure to any particular implementation of a STA.

[0056] Referring to FIG. 2b, the non-AP MLD 111 may be affiliated with multiple STAs 203a-203n (which may be referred to, for example, as STA1-STAn). Each of the affiliated STAs 203a-203n may include antenna(s) 205, a radio frequency (RF) transceiver 210, TX processing circuitry 215, and receive (RX) processing circuitry 225. The non-AP MLD 111 may also include a microphone 220, a speaker 230, a processor 240 (e.g., including processing circuitry), an input / output (I / O) interface (IF) 245, an input 250, a display 255, and memory 260. The memory 260 includes an operating system (OS) 261 and one or more applications 262.

[0057] The illustrated components of each affiliated STA 203a-203n may represent a PHY layer and an LMAC layer in the OSI networking model. In various embodiments, the illustrated components of the non-AP MLD 111 may represent a single UMAC layer and other higher layers in the OSI model, which are shared by all of the affiliated STAs 203a-203n.

[0058] For each affiliated STA 203a-203n, the RF transceiver 210 may receive from the antenna(s) 205, an incoming RF signal transmitted by an AP of the network 100. In various embodiments, each affiliated STA 203a-203n may operate at a different bandwidth,e.g., 2.4 GHz, 5 GHz, or 6 GHz, and accordingly the incoming RF signals received by each affiliated STA may be at a different frequency of RF. The RF transceiver 210 may down-convert the incoming RF signal to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal may be sent to the RX processing circuitry 225, which generates a processed baseband signal by filtering, decoding, and / or digitizing the baseband or IF signal. The RX processing circuitry 225 may transmit the processed baseband signal to the speaker 230 (such as for voice data) or to the processor 240 for further processing (such as for web browsing data).

[0059] For each affiliated STA 203a-203n, the TX processing circuitry 215 may receive analog or digital voice data from the microphone 220 or other outgoing baseband data (such as web data, e-mail, or interactive video game data) from the processor 240. The TX processing circuitry 215 may encode, multiplexe, and / or digitize the outgoing baseband data to generate a processed baseband or IF signal. The RF transceiver 210 may receive the outgoing processed baseband or IF signal from the TX processing circuitry 215 and up-converts the baseband or IF signal to an RF signal that is transmitted via the antenna(s) 205. In various embodiments, each affiliated STA 203a-203n may operate at a different bandwidth,e.g., 2.4 GHz, 5 GHz, or 6 GHz, the outgoing RF signals transmitted by each affiliated STA may be at a different frequency of RF.

[0060] The processor 240 may include one or more processors and execute the basic OS program 261 stored in the memory 260 in order to control the overall operation of the non-AP MLD 111. In an operation, the processor 240 may control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceiver 210, the RX processing circuitry 225, and the TX processing circuitry 215 in accordance with well-known principles. The processor 240 may also include processing circuitry configured to facilitate link deletion for seamless roaming. In various embodiments, the processor 240 may include at least one microprocessor or microcontroller.

[0061] The processor 240 may be also capable of executing other processes and programs resident in the memory 260, such as operations for facilitating link deletion for seamless roaming. The processor 240 may move data into or out of the memory 260 as required by an executing process. In various embodiments, the processor 240 may be configured to execute a plurality of applications 262, such as applications for facilitating link deletion for seamless roaming. The processor 240 may operate the plurality of applications 262 based on the OS program 261 or in response to a signal received from an AP. The processor 240 may be also coupled to the I / O interface 245, which provides non-AP MLD 111 with the ability to connect to other devices such as laptop computers and handheld computers. The I / O interface 245 may be the communication path between these accessories and the processor 240.

[0062] The processor 240 may be also coupled to the input 250 and the display 255. The operator of the non-AP MLD 111 may use the input 250 to enter data into the non-AP MLD 111. The display 255 may be a liquid crystal display, light emitting diode display, or other display capable of rendering text and / or at least limited graphics, such as from web sites. The memory 260 may be coupled to the processor 240. Part of the memory 260 could include a random-access memory (RAM), and another part of the memory 260 could include a flash memory or other read-only memory (ROM). The processor 240 may include various processing circuitry and / or multiple processors. For example, as used herein, including the claims, the term "processor" may include various processing circuitry, including at least one processor, wherein one or more of at least one processor, individually and / or collectively in a distributed manner, may be configured to perform various functions described herein. As used herein, when "a processor", "at least one processor", and "one or more processors" are described as being configured to perform numerous functions, these terms cover situations, for example and without limitation, in which one processor performs some of recited functions and another processor(s) performs other of recited functions, and also situations in which a single processor may perform all recited functions. Additionally, the at least one processor may include a combination of processors performing various of the recited / disclosed functions, e.g., in a distributed manner. At least one processor may execute program instructions to achieve or perform various functions.

[0063] Although FIG. 2b illustrates one example of non-AP MLD 111, various changes may be made to FIG. 2b. For example, various components in FIG. 2b could be combined, further subdivided, or omitted and additional components could be added according to particular needs. In an example, one or more of the affiliated STAs 203a-203n may include any number of antenna(s) 205 for MIMO communication with an AP 101. In an example, the non-AP MLD 111 may not include voice communication or the processor 240 could be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). Also, while FIG. 2b illustrates the non-AP MLD 111 configured as a mobile telephone or smartphone, non-AP MLDs may be configured to operate as other types of mobile or stationary devices.

[0064] A goal of seamless roaming is to provide mechanisms for a non-AP MLD to transition from the current AP MLD to the target AP MLD such that the time during which the connection is lost is minimal. The seamless roaming procedure may enable a non-AP MLD to remain in state 4 while transitioning from the current AP MLD to the target AP MLD.

[0065] The roaming procedure may comprise multiple stages. Two of the stages are a preparation stage and roam execution stage. During the preparation stage, the non-AP MLD may setup links with the target AP MLD and perform context transfer. Following this stage, the non-AP MLD may perform a roam execution procedure by sending a request frame to transition from current AP MLD to target AP MLD. The current AP MLD may process the request frame and send a response frame to the non-AP MLD after the transfer of context is complete.

[0066] These procedures should be designed to enable the non-AP MLD to seamlessly roam from the current to the target AP MLD.

[0067] FIG. 3 illustrates an example of link reconfiguration for adding and deleting links 300 according to various embodiments of the disclosure. The embodiment of the example of link reconfiguration for adding and deleting links 300 shown in FIG. 3 is for illustration only. Other embodiments of the example of link reconfiguration for adding and deleting links could be used without departing from the scope of this disclosure.

[0068] Referring to FIG. 3, the baseline specification provides a link reconfiguration procedure to enable the non-AP MLD to add or delete one or more of its links with its current AP MLD. The add or delete operation can be performed by the non-AP MLD by transmitting a link reconfiguration request frame to the current AP MLD as depicted in FIG. 3.

[0069] Embodiments of the disclosure recognize scenarios where a non-access point (non-AP) multi-link device (non-AP MLD) is connected to a seamless mobility domain (SMD). The SMD may include multiple access point (AP) multi-link devices (AP MLDs) where it can transition between the AP MLDs. There can be a seamless mobility domain management entity (SMD-ME) for the SMD. The SMD-ME may allow functionalities such as SMD-level authentication and association, IEEE 802.1X authenticator functions and robust security network association (RSNA) key management functions for non-AP MLDs across all AP MLDs within the SMD. The SMD may support two data path models between the non-AP MLD and the distribution system (DS). The first may be one that has one medium access control (MAC) service access point (SAP) for the SMD and the second may be one that has a separate MAC SAP per AP MLD of the SMD. The SMD may only have one of these data path models used. The SMD and the 802.1X Authenticator component in the corresponding SMD-ME may be uniquely identified by an SMD identifier.

[0070] When the non-AP MLD associates with an AP MLD 1 of the SMD, the non-AP MLD can setup links with the AP MLD 1, for example, by the use of a link reconfiguration procedure. At a later point in time, the non-AP MLD may want to transition to another AP MLD in the same SMD (for example AP MLD 2). When a non-AP MLD roams from AP MLD1 to AP MLD2, a procedure and behavior is needed for handling the links with the AP MLD1. For the remainder of this disclosure, AP MLD1 may be referred to as the old AP MLD and AP MLD2 may be referred to as the new AP MLD. AP MLD 1 may also be referred to as the current AP MLD and AP MLD 2 may be referred to as the target AP MLD.

[0071] Embodiments of the present disclosure provide a procedure that can be followed during a phase that occurs after the completion of the transition / ST execution procedure with the old AP MLD. During this period, the old AP MLD may continue to transmit data to the non-AP MLD. At the end of this phase (marked by a timeout value), the non-AP MLD and the old AP MLD may delete the links between them. The procedure to indicate the timeout value (timeout can also be called as nominal maximum DL draining period duration) and the corresponding behavior are described in section 1 herein. However, prior to the completion of this period, the non-AP MLD may also signal to the old AP MLD a termination of DL draining period. Procedures and behavior for this part are described in section 2 herein. In the same manner, the old AP MLD may also signal to the non-AP MLD about the termination of the DL draining period. The procedures and behavior for this part are described in section 3 herein.

[0072] In the disclosure, a number of solutions may be presented for handling link deletion at the current AP MLD, including (1) timeout based deletion; (2) non-AP MLD side indication based deletion and signaling; and (3) AP MLD side indication based deletion and signaling

[0073] (1) Timeout based deletion

[0074] FIG. 4 illustrates an example procedure 400 for timeout based link deletion according to various embodiments of the disclosure. The embodiment of the example procedure 400 for timeout based link deletion shown in FIG. 4 is for illustration only. Other embodiments of the example procedure for timeout based link deletion could be used without departing from the scope of this disclosure.

[0075] Referring to FIG. 4, the procedure 400 may begin at operation 402, where a determination is made whether there is a timeout after roam execution completion. If there is no timeout after roam execution completion, at operation 404, no action may be taken. If there is timeout after roam execution completion, then at operation 406, all the links of the non-AP MLD may be deleted.

[0076] According to an embodiment, there can be a timeout value after which the links at the old AP MLD can be deleted. This timeout may be an amount of time that is needed to drain the downlink buffer of the old AP MLD. If the timeout value is zero, the links may be deleted right after the completion of the execution procedure

[0077] FIG. 5 illustrates an example procedure 500 for timeout value advertisement by the AP MLD according to various embodiments of the disclosure. The embodiment of the example procedure 500 for timeout value advertisement by the AP MLD shown in FIG. 5 is for illustration only. Other embodiments of the example procedure for timeout value advertisement by the AP MLD could be used without departing from the scope of this disclosure.

[0078] Referring to FIG. 5, the procedure 500 may begin at operation 502, where a determination is made whether the AP wants to advertise a timeout value. If the AP does not want to advertise a timeout value, at operation 504, no action may be taken. If the AP wants to advertise a timeout value, then at operation 506, the AP MLD may advertise the timeout value in management frames.

[0079] FIG. 6 illustrates an example procedure 600 for timeout value in a response message by the AP MLD according to various embodiments of the disclosure. The embodiment of the example procedure 600 for timeout value in a response message by the AP MLD shown in FIG. 6 is for illustration only. Other embodiments of the example procedure for timeout value in a response message by the AP MLD could be used without departing from the scope of this disclosure.

[0080] Referring to FIG. 6, the procedure 600 may begin at operation 602, where a determination is made whether the AP wants to provide a timeout value to the non-AP MLD. If the AP does not want to provide a timeout value to the non-AP MLD, at operation 604, no action may be taken. If the AP wants to provide a timeout value to the non-AP MLD, at operation 606, the AP MLD may include the timeout value in the link reconfiguration response frame.

[0081] The link reconfiguration response frame that can carry the timeout value can have a format as shown in Table 1.

[0082] OrderMeaning1Category2Protected EHT / UHR Action3Dialog Token4Timeout5Count6Reconfiguration Status List7Group Key Data (optional)8OCI element (optional)9Basic Multi-link element (optional)

[0083] The order can be different than that shown in this example. There can also be additional information items present.When a non-AP MLD receives a timeout value from an AP MLD in the link reconfiguration response frame used as a roam response message, the non-AP MLD may understand that its links with that AP MLD can be deleted after a timeout period of time.

[0084] FIG. 7 illustrates an example control field format for the reconfiguration multi-link element 700 according to various embodiments of the disclosure. The embodiment of the example control field format for the reconfiguration multi-link element 700 shown in FIG. 7 is for illustration only. Other embodiments of the example control field format for the reconfiguration multi-link element could be used without departing from the scope of this disclosure.

[0085] Referring to FIG. 7, the timeout value may also be carried in the reconfiguration multi-link element. The timeout value may be set to 1 if the timeout is present in the reconfiguration multi-link element and the timeout value may be set to 0 if it is absent.

[0086] FIG. 8 illustrates an example STA information field format for the reconfiguration multi-link element 800 according to various embodiments of the disclosure. The embodiment of the example STA information field format for the reconfiguration multi-link element 800 shown in FIG. 8 is for illustration only. Other embodiments of the example STA information field format for the reconfiguration multi-link element could be used without departing from the scope of this disclosure.

[0087] Referring to FIG. 8, if the timeout value present bit is set to 1, the STA information field format may carry a timeout value and the STA information length value may be set to reflect the presence of the timeout value.

[0088] According to an embodiment, the timeout value may be carried in a newly defined element.

[0089] According to an embodiment, the timeout value may also be advertised by the AP MLD in a SMD information element and can be applicable for all the AP MLDs in the SMD.

[0090] (2) Non-AP MLD side indication based deletion

[0091] According to one embodiment, the non-AP MLD can provide an indication to the old AP MLD to delete its links. The non-AP MLD can transmit a message to the old AP MLD to inform the old AP MLD about the need to delete the links.

[0092] The message can contain at least one or more of the information items as shown in Table 2.

[0093] Information itemsDescriptionLinks to deleteOne or more information items that can indicate the links that can be deleted. For example, the link ID, basic multi-link element that can show the new set of links and thus indicate the AP MLD to delete the old set of links.DeadlineOne or more information items that can indicate a time by which the links can be deleted.AP MLD identifierOne or more information items that can indicate the identifier of the AP MLD. E.g., AP MLD MAC address, AP MLD ID, etc.Early termination of DL (downlink) dataOne or more information items that can indicate that the DL retrieval is terminated / completed. For example, a bit that can take a predetermined value to make the indication and to another value to indicate otherwise, a field (e.g., a type field) that can carry a predetermined value (e.g., 3) to make the indication. The completion of the downlink retrieval can be indicated for all the traffic types together or can be indicated per traffic category. For example, for different TIDs, ACs, etc.Traffic type for which early termination of DL data appliesOne or more information items indicating a list of traffic types for which early termination of DL data applies. For example, there can be a TID bitmap. A value of 1 in the bit position i of the TID bitmap can indicate to the recipient that the indication for an early termination of DL data applies to the TID i. Another example can be to indicate individual TIDs coupled with a field that carries a value to indicate if an early termination of DL data applies to that TID or not.Another example is an AC bitmap.

[0094] FIG. 9 illustrates an example non-AP side procedure 900 for link deletion according to various embodiments of the disclosure. The embodiment of the example non-AP side procedure 900 for link deletion shown in FIG. 9 is for illustration only. Other embodiments of the example non-AP side procedure for link deletion could be used without departing from the scope of this disclosure.When a non-AP MLD has completed the roam execution procedure with the old AP MLD, the old AP MLD may delete all the links with the non-AP MLD via the link deletion message.

[0095] Referring to FIG. 9, the procedure 900 may begin at operation 902, where a determination is made whether the non-AP MLD wants to delete its links after roam execution process completion. If the non-AP MLD does not want to delete its links after roam execution process completion, at operation 904, no action may be taken. If the AP wants to delete its links after roam execution process completion, at operation 906, the AP MLD may transmit a link reconfiguration request frame.

[0096] According to an embodiment, the link deletion message may be a link reconfiguration request frame transmitted to the old AP MLD. The link reconfiguration request frame may indicate in the reconfiguration operation type a value corresponding to delete link operation. The complete per-STA profile may be absent in such a message (e.g., by setting the complete profile subfield in the STA control field of the reconfiguration multi-link element to 0).

[0097] According to an embodiment, the link deletion message may be a link reconfiguration notify frame. The link reconfiguration notify frame may carry a reconfiguration ML element that can indicate a link deletion operation for all the links established with the AP MLD if the non-AP MLD has completed the roam execution procedure with the AP MLD. According to an embodiment, the link reconfiguration notify frame may be a UHR frame with a type field that can indicate an early termination of DL transmissions or completion of DL retrieval.

[0098] According to an embodiment, the message may be in the form of an A-control subfield which can contain a bit that can indicate the link deletion or termination. The bit may take a value of 1 to make an indication of link deletion or early termination and to another value to indicate otherwise. The indication can be carried in a QoS Null, QoS Data or Management frame.

[0099] FIG. 10 illustrates an example procedure 1000 for transmitting a link deletion message to the new AP according to various embodiments of the disclosure. The embodiment of the example procedure 1000 for transmitting a link deletion message to the new AP shown in FIG. 10 is for illustration only. Other embodiments of the example procedure for transmitting a link deletion message to the new AP could be used without departing from the scope of this disclosure.

[0100] According to an embodiment, the link deletion message may be transmitted to the new AP MLD. For example, if the DLDrainTime ends without an early termination the non-AP MLD may make an indication to the new AP MLD.

[0101] According to an embodiment, the indication may also be made in the form of a status code instead of a bit based indication.

[0102] Referring to FIG. 10, the procedure 1000 may begin at operation 1002, where a determination is made whether the old AP MLD is unreachable. If the old AP MLD is not unreachable, at operation 1004, no action may be taken. If the old AP MLD is unreachable, at operation 1006, the non-AP MLD may transmit a link delete message to the new AP MLD.

[0103] According to an embodiment, the link deletion message may be transmitted to the old AP MLD.

[0104] FIG. 11 illustrates an example procedure 1100 for transmitting a link deletion message to the old AP according to various embodiments of the disclosure. The embodiment of the example procedure 1100 for transmitting a link deletion message to the old AP shown in FIG. 11 is for illustration only. Other embodiments of the example procedure for transmitting a link deletion message to the old AP could be used without departing from the scope of this disclosure.

[0105] Referring to FIG. 11, the procedure 1100 may begin at operation 1102, where a determination is made whether the old AP MLD is unreachable. If the old AP MLD is not unreachable, at operation 1104, no action may be taken. If the old AP MLD is unreachable, at operation 1106, the non-AP MLD may transmit a link delete message to the old AP MLD.

[0106] According to an embodiment, the AP MLD may accept a link reconfiguration request frame that requests to delete all the links setup with that AP MLD if the non-AP MLD has completed the roam execution stage with the AP MLD, i.e., the non-AP MLD has already roamed to another AP MLD.

[0107] (3) AP MLD side indication based deletion

[0108] According to an embodiment, the AP MLD may also provide a notification of link delete to the non-AP MLD. For example, when the AP MLD has exhausted its downlink data that was buffered for the non-AP MLD. Instead of a notification of link delete, the AP MLD may also provide a notification that the DL data has been exhausted or that DL data transmission can be terminated. The notification may be solicited by the non-AP MLD or can be unsolicited. The notification may comprise at least one or more of the information items as shown in Table 3.

[0109] Information itemDescriptionNo DL data indicationOne or more information items that can indicate that there is no more pending DL data or that the AP MLD can no longer transmit any DL data to the non-AP MLD. For example, a bit that can take a predetermined value (e.g., 1) to make the indication and to another predetermined value (e.g., 0) to indicate otherwise.Early termination of DL (downlink) dataOne or more information items that can indicate that the DL retrieval is terminated / completed. For example, a bit that can take a predetermined value to make the indication and to another value to indicate otherwise, a field (e.g., a type field) that can carry a predetermined value (e.g., 3) to make the indication. The completion of the downlink retrieval can be indicated for all the traffic types together or can be indicated per traffic category. E.g., for different TIDs, ACs, etc.Traffic type for which early termination of DL data appliesOne or more information items indicating a list of traffic types for which early termination of DL data applies. For example, there can be a TID bitmap. A value of 1 in the bit position i of the TID bitmap can indicate to the recipient that the indication for an early termination of DL data applies to the TID i. Another example can be to indicate individual TIDs coupled with a field that carries a value to indicate if an early termination of DL data applies to that TID or not.Another example is an AC bitmap.

[0110] FIG. 12 illustrates an example AP side procedure 1200 for link deletion according to various embodiments of the disclosure. The embodiment of the example AP side procedure 1200 for link deletion shown in FIG. 12 is for illustration only. Other embodiments of the example AP side procedure for link deletion could be used without departing from the scope of this disclosure.Referring to FIG. 12, the procedure 1200 may begin at operation 1202, where a determination is made whether the AP MLD has exhausted the downlink (DL) buffer. If the AP MLD has not exhausted the DL, at operation 1204, no action may be taken. If the AP MLD AP MLD has exhausted the DL buffer, at operation 1206, the AP MLD may transmit a link delete notification to the non-AP MLD.

[0111] The AP MLD may transmit a link reconfiguration notify frame to the non-AP MLD. The link reconfiguration notify frame may carry a reconfiguration ML element that can indicate a link deletion operation for all the links established with the AP MLD if the non-AP MLD has completed the roam execution procedure with the AP MLD. According to an embodiment, the link reconfiguration notify frame may be a UHR frame with a type field that can indicate an early termination of DL transmissions or completion of DL retrieval.

[0112] According to an embodiment, the AP MLD may transmit a link reconfiguration request / response frame to the non-AP MLD. The link reconfiguration request / response frame may carry an indication to indicate an early termination of DL transmissions or completion of DL retrieval.

[0113] FIG. 13 illustrates an example procedure 1300 for transmitting a link deletion message through the new AP MLD according to various embodiments of the disclosure. The embodiment of the example procedure 1300 for transmitting a link deletion message through the new AP MLD shown in FIG. 13 is for illustration only. Other embodiments of the example procedure for transmitting a link deletion message through the new AP MLD could be used without departing from the scope of this disclosure.

[0114] The link delete operation may be performed by the old AP MLD by having the new AP MLD transmit the link delete to the non-AP MLD. For example, if the non-AP MLD is out of reach of the old AP MLD.

[0115] Referring to FIG. 13, the procedure 1300 may begin at operation 1302, where a determination is made whether the non-AP MLD is unreachable for the old AP MLD. If the non-AP MLD is not unreachable for the old AP MLD, at operation 1304, no action may be taken. If the non-AP MLD is unreachable for the old AP MLD, at operation 1306, the new AP MLD may transmit the link delete message.

[0116] FIG. 14 illustrates an example procedure 1400 for transmitting a link deletion message through the old AP MLD according to various embodiments of the disclosure. The embodiment of the example procedure 1400 for transmitting a link deletion message through the old AP MLD shown in FIG. 14 is for illustration only. Other embodiments of the example procedure for transmitting a link deletion message through the old AP MLD could be used without departing from the scope of this disclosure.

[0117] The link delete operation may be performed by the old AP MLD by transmitting the link delete message to the non-AP MLD. For example, if the non-AP MLD is within the reach of the old AP MLD.

[0118] Referring to FIG. 14, the procedure 1400 may begin at operation 1402, where a determination is made whether the non-AP MLD is reachable for the old AP MLD. If the non-AP MLD is not reachable for the old AP MLD, at operation 1404, no action may be taken. If the non-AP MLD is reachable for the old AP MLD, at operation 1406, the old AP MLD can transmit the link delete message.

[0119] FIG. 15 illustrates an example procedure 1500 for non-AP side inference of completion of buffer on the AP MLD side according to various embodiments of the disclosure. The embodiment of the example procedure 1500 for non-AP side inference of completion of buffer on the AP MLD side shown in FIG. 15 is for illustration only. Other embodiments of the example procedure for non-AP side inference of completion of buffer on the AP MLD side could be used without departing from the scope of this disclosure.

[0120] Referring to FIG. 15, the procedure 1500 may begin at operation 1502, where a determination is made whether the non-AP MLD receives a link delete message which deletes links with the old AP MLD. If the non-AP MLD does not receive a link delete message which deletes links with the old AP MLD, at operation 1504, no action may be taken. If the non-AP MLD does receive a link delete message which deletes links with the old AP MLD, at operation 1506, the non-AP MLD may understand that the buffer for downlink frames on the old AP MLD is exhausted.

[0121] FIG. 16 illustrates an example method 1600 performed by a first AP MLD STA in a wireless communication system according to various embodiments of the disclosure. The method 1600 of FIG. 16 may be performed by any of the STAs 111-114 of FIG. 1, such as the STA 111 of FIG. 2B, and a corresponding method may be performed by any of the APs 101-103 of FIG. 1, such as AP 101 of FIG. 2A. The method 1600 is for illustration only and other embodiments can be used without departing from the scope of the present disclosure.

[0122] Referring to FIG. 16, the method 1600 may begin at operation 1602, where the first AP MLD may receive, from a non-AP MLD that is associated with the first AP MLD and that has links setup with the first AP MLD, a roam request message to roam from the first AP MLD to a second AP MLD. At operation 1604, the first AP MLD may transmit data to the non-AP MLD for a duration of time after roam execution completion. At operation 1606, the first AP MLD may perform a link deletion procedure for deleting the links that were setup between the non-AP MLD and the first AP MLD.

[0123] In various embodiments, the link deletion procedure may comprise a timeout based deletion procedure that includes a timeout duration, and the first AP MLD transmits the timeout duration to the non-AP MLD via a response message to the roam request message, and deletes the links that were setup between the non-AP MLD and the first AP MLD after expiration of the timeout duration.

[0124] In various embodiments, the response message may comprise a link reconfiguration response frame that carries the timeout duration.

[0125] In various embodiments, the link reconfiguration response frame may include information associated with at least one of a category, a protected ultra-high reliability / extremely high throughput (UHR / EHT) action, a dialog token, a timeout, a count, a reconfiguration status list, group key data, an operation channel information (OCI) element target, and a multi-link element.

[0126] In various embodiments, the duration of time may comprise a downlink draining period which includes an amount of time needed to drain a downlink buffer of the first AP MLD.

[0127] In various embodiments, the first AP MLD may receive, from the non-AP MLD, a link reconfiguration notify frame that includes an indication of early termination of the downlink draining period, delete the links that were setup between the non-AP MLD and the first AP MLD based on the indication of early termination of the downlink draining period.

[0128] In various embodiments, the first AP MLD may transmit an indication to the non-AP MLD to delete the links that were setup between the non-AP MLD and the first AP MLD.

[0129] It will be appreciated that various embodiments of the disclosure according to the claims and description in the specification can be realized in the form of hardware, software or a combination of hardware and software.

[0130] Any such software may be stored in non-transitory computer readable storage media. The non-transitory computer readable storage media store one or more computer programs (software modules), the one or more computer programs include computer-executable instructions that, when executed by one or more processors of an electronic device individually or collectively, cause the electronic device to perform a method of the disclosure.

[0131] Any such software may be stored in the form of volatile or non-volatile storage such as, for example, a storage device like read only memory (ROM), whether erasable or rewritable or not, or in the form of memory such as, for example, random access memory (RAM), memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a compact disk (CD), digital versatile disc (DVD), magnetic disk or magnetic tape or the like. It will be appreciated that the storage devices and storage media are various embodiments of non-transitory machine-readable storage that are suitable for storing a computer program or computer programs comprising instructions that, when executed, implement various embodiments of the disclosure. Accordingly, various embodiments provide a program comprising code for implementing apparatus or a method as claimed in any one of the claims of this specification and a non-transitory machine-readable storage storing such a program.

[0132] The flowcharts herein illustrate example methods or processes that can be implemented in accordance with the principles of the present disclosure and various changes could be made to the methods or processes illustrated in the flowcharts.　For example, while shown as a series of operations, various operations could overlap, occur in parallel, occur in a different order, or occur multiple times. In an example, operations may be omitted or replaced by other operations.

[0133] While the disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents.

Claims

A method performed by a first access point (AP) multi-link device (MLD) of a seamless mobility domain, the method comprising:receiving, from a non-AP MLD that is associated with the first AP MLD and that has links setup with the first AP MLD, a roam request message for roaming from the first AP MLD to a second AP MLD of the seamless mobility domain;transmitting data to the non-AP MLD for a duration of time after a roam execution completion; andperforming a link deletion procedure for deleting the links setup between the non-AP MLD and the first AP MLD.The method of claim 1, wherein the link deletion procedure comprises a timeout based deletion procedure that includes a timeout duration, and the method further comprising:transmitting the timeout duration to the non-AP MLD via a response message corresponding to the roam request message; anddeleting the links setup between the non-AP MLD and the first AP MLD after an expiration of the timeout duration,wherein the response message comprises a link reconfiguration response frame that carries the timeout duration.The method of claim 2, wherein the link reconfiguration response frame includes information associated with at least one of a category, a protected ultra-high reliability / extremely high throughput (UHR / EHT) action, a dialog token, a timeout, a count, a reconfiguration status list, group key data, an operation channel information (OCI) element target, and a multi-link element.The method of claim 1, wherein the duration of time comprises a downlink draining period which includes an amount of time needed to drain a downlink buffer of the first AP MLD,wherein the link deletion procedure comprises:receiving, from the non-AP MLD, a link reconfiguration notify frame that includes an indication of early termination of the downlink draining period; anddeleting the links setup between the non-AP MLD and the first AP MLD based on the indication of early termination of the downlink draining period.The method of claim 1, wherein the link deletion procedure comprises transmitting an indication to the non-AP MLD to delete the links setup between the non-AP MLD and the first AP MLD.A method performed by a non-access point (AP) multi-link device (MLD) of a seamless mobility domain, the method comprising:transmitting, to a first AP MLD that is associated with the non-AP MLD and that has links setup with the non-AP MLD, a roam request message for roaming from the first AP MLD to a second AP MLD of the seamless mobility domain;receiving data from the first AP MLD for a duration of time after a roam execution completion; andperforming a link deletion procedure for deleting the links setup between the non-AP MLD and the first AP MLD.The method of claim 6, wherein the link deletion procedure comprises a timeout based deletion procedure that includes a timeout duration, and the method further comprising:receiving the timeout duration from the first AP MLD via a response message corresponding to the roam request message; anddeleting the links setup between the non-AP MLD and the first AP MLD after an expiration of the timeout duration,wherein the response message comprises a link reconfiguration response frame that carries the timeout duration.The method of claim 7, wherein the link reconfiguration response frame includes information associated with at least one of a category, a protected ultra-high reliability / extremely high throughput (UHR / EHT) action, a dialog token, a timeout, a count, a reconfiguration status list, group key data, an operation channel information (OCI) element target, and a multi-link element.The method of claim 6, wherein the duration of time comprises a downlink draining period which includes an amount of time needed to drain a downlink buffer of the first AP MLD,wherein the link deletion procedure comprises:transmitting, to the first AP MLD, a link reconfiguration notify frame that includes an indication of early termination of the downlink draining period; anddeleting the links setup between the non-AP MLD and the first AP MLD based on the indication of early termination of the downlink draining period.The method of claim 6, wherein the link deletion procedure comprises receiving an indication from the first AP MLD to delete the links setup between the non-AP MLD and the first AP MLD.An electronic device comprising:at least one processor including processing circuitry; and　memory storing instructions, wherein the instructions, when executed by the at least one processor individually or collectively, cause the electronic device to:receive, from a non-access point (AP) multi-link device ( MLD) that is associated with a first AP MLD and that has links setup with the first AP MLD, a roam request message for roaming from the first AP MLD to a second AP MLD of a seamless mobility domain;transmit data to the non-AP MLD for a duration of time after a roam execution completion; andperform a link deletion procedure for deleting the links setup between the non-AP MLD and the first AP MLD.The electronic device of claim 11, wherein:the link deletion procedure comprises a timeout based deletion procedure that includes a timeout duration, andthe instructions, when executed by the at least one processor individually or collectively, cause the electronic device to:transmit the timeout duration to the non-AP MLD via a response message corresponding to the roam request message; anddelete the links setup between the non-AP MLD and the first AP MLD after an expiration of the timeout duration,wherein the response message comprises a link reconfiguration response frame that carries the timeout duration.The electronic device of claim 12, wherein the link reconfiguration response frame includes information associated with at least one of a category, a protected ultra-high reliability / extremely high throughput (UHR / EHT) action, a dialog token, a timeout, a count, a reconfiguration status list, group key data, an operation channel information (OCI) element target, and a multi-link element.The electronic device of claim 11, wherein the duration of time comprises a downlink draining period which includes an amount of time needed to drain a downlink buffer of the first AP MLD,wherein the instructions, when executed by the at least one processor individually or collectively, cause the electronic device to:receive, from the non-AP MLD, a link reconfiguration notify frame that includes an indication of early termination of the downlink draining period; anddelete the links setup between the non-AP MLD and the first AP MLD based on the indication of early termination of the downlink draining period.The electronic device of claim 11, wherein the instructions, when executed by the at least one processor individually or collectively, cause the electronic device to transmit an indication to the non-AP MLD to delete the links setup between the non-AP MLD and the first AP MLD.

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