Access point multilink device AP MLD and non-AP MLD, computer implementation method

Abstract

The present disclosure relates to a first access point multilink device, AP MLD, non-AP MLD, and computer-implemented methods for connecting to a wireless network. The first AP MLD comprises one or more APs attached to the first AP MLD, and the one or more APs comprise a first AP; a processor coupled to the first AP, the processor configured to communicate with a second AP MLD to determine that the first AP MLD is a roaming AP MLD, form an affiliation relationship with a second AP of one or more non-collocated APs affiliated to the second AP MLD, send information about the first AP affiliated to the first AP MLD to a non-AP MLD associated with the second AP MLD, associate with the non-AP MLD, and, after the non-AP MLD performs roaming from the second AP MLD to the first AP MLD, send information about the first AP affiliated to the first AP MLD to the second AP MLD. And communicating with the non-AP MLD via the first AP MLD.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications, and more particularly to, for example but not limited to, a first access point multi-link device AP MLD for connecting to a wireless network, a non-AP MLD, and a computer-implemented method for facilitating communications in a wireless network. Background Art

[0002] Wireless local area network (WLAN) devices are widely deployed in various environments to provide various communication services such as video, cloud access, broadcasting, and offloading. Some of these environments have many access point (AP) stations and non-AP stations in a geographically limited area. Since the late 1990s, WLAN technology has been moving towards increasing data rates and has continued to grow in various markets such as homes, enterprises, and hotspots. The recently released standard (IEEE 802.11ax-2021) provides improved network performance in high-density scenarios by adopting OFDMA and MU-MIMO technologies. These improvements can be used to support environments such as outdoor hotspots, dense residential / office areas, and stadiums.

[0003] However, there is a general need for improved WLANs to support real-time or delay-sensitive applications that have stringent requirements on latency and packet loss rates. These applications include online gaming, real-time video streaming, virtual reality, and remote-controlled drones and vehicles.

[0004] The descriptions presented in the Background section should not be regarded as prior art merely because they are presented in the Background section.The Background section may describe aspects or embodiments of the present disclosure. Summary of the invention

[0005] One aspect of the present disclosure provides a first access point multi-link device APMLD for connecting to a wireless network, the first AP MLD comprising one or more APs affiliated with the first AP MLD, including a first AP, and a processor coupled to the first AP. The processor is configured to communicate with a second AP MLD to determine that the first AP MLD is a roaming AP MLD. The processor is configured to form an affiliated relationship with a second AP among one or more non-collocated APs affiliated with the second AP MLD. The processor is configured to send information about the first AP affiliated with the first AP MLD to a non-AP MLD associated with the second AP MLD. The processor is configured to associate with the non-AP MLD. The processor is configured to communicate with the non-AP MLD via the first AP MLD after the non-AP MLD performs roaming from the second AP MLD to the first AP MLD.

[0006] In some embodiments, communicating with the second AP MLD to determine that the first AP MLD is a roaming AP MLD includes: receiving a frame from the second AP MLD, the frame including information for determining which AP MLD can become a roaming AP MLD; and determining that the first AP MLD is the roaming AP MLD based on the information in the frame.

[0007] In some embodiments, the frame is a beacon frame.

[0008] In some embodiments, the frame includes traffic state information of the second AP MLD.

[0009] In some embodiments, determining that the first AP MLD is a roaming AP MLD includes: comparing the stack flow of the first AP MLD with the stack flow indicated by the flow status information of the second AP MLD, and determining that the first AP MLD is a roaming AP MLD if the stack flow of the first AP MLD is less than the stack flow indicated by the flow status information of the second AP MLD.

[0010] In some embodiments, the frame includes buffer capacity information of the second AP MLD.

[0011] In some embodiments, determining that the first AP MLD is a roaming AP MLD includes comparing a buffer size of the first AP MLD with a buffer size indicated by the buffer capacity information of the second AP MLD, and determining that the first AP MLD is a roaming AP MLD if the buffer size of the first AP MLD is greater than the buffer size indicated by the buffer capacity information of the second AP MLD.

[0012] In some embodiments, performing the process of associating with the non-AP MLD includes at least one of an authentication, security, and block validation protocol with the non-AP MLD.

[0013] One aspect of the present invention provides a non-access point multi-link device APMLD for connecting to a wireless network, comprising a processing circuit. The processing circuit is configured to associate with a first AP attached to a first AP MLD and communicate with the first AP attached to the first AP MLD. The processing circuit is configured to receive information about a second AP MLD. The processing circuit is configured to associate with a second AP attached to the second AP MLD and the first AP MLD, wherein the first AP and the second AP are not collocated. The processing circuit is configured to perform roaming from the first AP attached to the first AP MLD to the second AP attached to the second AP MLD. The processing circuit is configured to communicate with the second AP attached to the second APMLD.

[0014] In some embodiments, the processing circuit is further configured to associate with the second AP affiliated with the second AP MLD by executing at least one of an authentication, security, and block validation protocol with the second AP MLD.

[0015] In some embodiments, the processing circuit is further configured to activate both the first AP affiliated with the first AP MLD and the second AP affiliated with the second AP MLD during roaming.

[0016] In some embodiments, the processing circuit is further configured to be active only for the second AP affiliated with the second AP MLD after roaming.

[0017] One aspect of the present invention provides a computer-implemented method for facilitating communication in a wireless network, the method comprising: communicating, by a first AP affiliated with a first access point multi-link device AP MLD, with a second AP MLD to determine that the first AP MLD is a roaming AP MLD; forming an affiliated relationship with a second AP among one or more non-collocated APs affiliated with the second AP MLD; sending information about the first AP affiliated with the first AP MLD to a non-AP MLD associated with the second AP MLD; associating with the non-AP MLD; and communicating with the non-AP MLD via the first AP MLD after the non-AP MLD performs roaming from the second AP MLD to the first AP MLD.

[0018] In some embodiments, communicating with the second AP MLD to determine that the first AP MLD is a roaming AP MLD includes: receiving a frame from the second AP MLD, the frame including information for determining which AP MLD can become the roaming AP MLD, and determining that the first AP MLD is the roaming AP MLD based on the information in the frame.

[0019] In some embodiments, the frame is a beacon frame.

[0020] In some embodiments, the frame includes traffic state information of the second AP MLD.

[0021] In some embodiments, determining that the first AP MLD is the roaming AP MLD includes: comparing the stack traffic of the first AP MLD with the stack traffic indicated by the traffic status information of the second AP MLD, and determining that the first AP MLD is the roaming AP MLD if the stack traffic of the first AP MLD is less than the stack traffic indicated by the traffic status information of the second AP MLD.

[0022] In some embodiments, the frame includes buffer capacity information of the second AP MLD.

[0023] In some embodiments, determining that the first AP MLD is the roaming AP MLD includes: comparing a buffer size of the first AP MLD with a buffer size indicated by the buffer capacity information of the second AP MLD, and determining that the first AP MLD is the roaming AP MLD if the buffer size of the first AP MLD is greater than the buffer size indicated by the buffer capacity information of the second AP MLD.

[0024] In some embodiments, associating with the non-AP MLD includes performing at least one of an authentication, security, and block validation protocol with the non-AP MLD. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 An example of a wireless communication network according to an embodiment is shown.

[0026] Figure 2 An example of a timing diagram illustrating inter-frame space (IFS) relationships between wireless devices according to an embodiment.

[0027] Figure 3 Examples of OFDM symbols and OFDMA symbols according to an embodiment are shown.

[0028] Figure 4A An example of a PPDU format according to an embodiment is shown. The PPDU may be used for SU and MU transmission.

[0029] Figure 4B Another example of a PPDU format according to an embodiment is shown.

[0030] Figure 5A schematic diagram showing an example of an electronic device according to an embodiment.

[0031] Figure 6 A schematic diagram showing an example of a transmitter according to an embodiment is shown.

[0032] Figure 7 A schematic diagram showing an example of a receiver according to an embodiment is shown.

[0033] Figure 8 An MLO operation with two links is shown.

[0034] Fig. 9 An example of a roaming configuration is shown.

[0035] Fig.10 An example of normal MLD operation according to an embodiment is shown.

[0036] Fig.11 A roaming AP MLD setup according to an embodiment is shown.

[0037] Fig.12 It is shown that AP MLD A becomes a roaming AP MLD, and APs affiliated with different AP MLDs form a new affiliated relationship with the roaming AP MLD.

[0038] Fig.13 A roaming mode setting according to an implementation is shown.

[0039] Fig.14 A roaming mode setting according to an implementation is shown.

[0040] Fig.15 The MLD configuration before roaming is shown according to an implementation scheme.

[0041] Fig.16 MLD configuration during roaming according to an embodiment is shown.

[0042] Fig.17 The MLD configuration after roaming is shown according to an implementation scheme.

[0043] Fig.18 A ladder diagram for configuring roaming between AP MLDs according to an embodiment is shown.

[0044] Fig.19 A flow chart showing an example process for roaming between MLDs, according to an embodiment. DETAILED DESCRIPTION

[0045] The detailed description provided below is intended to describe various implementations and is not intended to represent a unique implementation. As will be appreciated by those skilled in the art, the described implementations may be modified in various ways, all without departing from the scope of the present invention. Therefore, the drawings and descriptions are considered to be illustrative and not restrictive in nature. The same reference numerals represent the same elements.

[0046] The following detailed description is described with reference to a WLAN system based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless standard (including current and future revisions). However, one of ordinary skill in the art will readily appreciate that the teachings herein are applicable to other network environments, such as cellular telecommunication networks and wired telecommunication networks.

[0047] In some embodiments, an apparatus or device such as an AP station and a non-AP station may include one or more hardware and software logic structures for performing one or more operations described herein. For example, an apparatus or device may include at least one storage unit and at least one processor, the storage unit storing instructions executable by a hardware processor installed in the apparatus, and the processor being configured to perform the operations or processes described in the present disclosure. In addition, the apparatus may include one or more other hardware or software elements, such as a network interface and a display device.

[0048] Figure 1An example of a wireless communication network according to an embodiment is shown. The wireless communication network may include a basic service set (BSS) 10. BSS10 provides a basic organizational unit and includes multiple wireless devices, which may be referred to as stations (STAs). In some implementations, multiple STAs may be included inside a wireless device. According to the IEEE 802.11 standard, a STA may be a logical entity of a single addressable instance of a medium access control (MAC) and a physical layer (PHY) interface to a wireless medium (WM). STA may be an access point (AP) STA and a non-AP STA. AP STA may be an entity containing one STA and provides access to a distributed system service via a wireless medium for associated STAs. Non-AP STA may be a STA that is not included in an AP STA. AP STA and non-AP STA may be collectively referred to as STA. To simplify the description, an AP STA may be referred to as an AP, and a non-AP STA may be referred to as a STA or a station. AP STA may include, be implemented as, or be included in a wireless device, such as a centralized controller, a base station (BS), a node B, a base transceiver system (BTS), a site controller, a network adapter, and a router. Similarly, a non-AP STA may include, be implemented as, or be included in a wireless communication device, such as a terminal, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a mobile terminal, a mobile subscriber unit, a laptop, a smartphone, a battery pack, and a non-mobile computing device.

[0049] refer to Figure 1, a BSS 10 in a wireless communication network may include an AP STA 11 and a plurality of non-AP STAs 12. The AP STA 11 may transmit information to a single station in the non-AP STA 12, or may transmit information to two or more stations in the non-AP STA 12 at the same time. For simultaneous transmission, the AP STA 11 may use a downlink (DL) multi-user (MU) transmission scheme, such as DL orthogonal frequency division multiplexing access (OFDMA) and DL multi-user multiple input multiple output (DL MU-MIMO). Similarly, each non-AP STA 12 may transmit information to the AP STA alone, or may transmit information simultaneously with one or more other non-AP STAs 12. For simultaneous transmission, the non-AP STA 12 may use an uplink (UL) MU transmission scheme, such as UL OFDMA and UL MU-MIMO. In MU-MIMO transmission, a transmitting station may transmit information to multiple receiving stations simultaneously using one or more antennas on the same subcarrier. Different spatial streams may be used as different resources in MU-MIMO transmission. In OFDMA transmission, a transmitting station can send information to multiple receiving stations simultaneously through different subcarrier groups. Different frequencies (subcarriers) can be used as different resources in OFDMA transmission.

[0050] Figure 2 An example of a timing diagram illustrating inter-frame space (IFS) relationships between wireless devices according to an embodiment. Figure 2 The carrier sense multiple access (CSMA) / collision avoidance (CA) frame transmission process is described to prevent collisions between frames on the channel. These frames may include data frames, control frames, or management frames exchanged between wireless devices.

[0051] Data frames can be used for the transmission of data, which is forwarded to higher layers in the receiving station. Figure 2In the embodiment of the present invention, when the medium is busy, the access of the wireless device to the medium is postponed until the IFS duration has passed. For example, when the distributed coordination function (DCF) IFS (DIFS) expires, the wireless device can send a data frame after completing the backoff period. Management frames can be used to exchange management information, which is not forwarded to the higher layer in the receiving station. Management frames include beacon frames, association request / response frames, disassociation frames, reassociation request / response frames, probe request / response frames, and authentication request / response frames and action frames. Control frames can be used to control access to the medium. Control frames include request to send (RTS) frames, clear to send (CTS) frames and acknowledgement (ACK) frames, BlockAck request / response frames, NDP (empty data PPDU) announcement frames. If the control frame is not a response frame to another frame, the wireless device can send the control frame after performing the backoff operation when the DIFS has passed. However, if the control frame is a response frame to another frame, the wireless device can send the control frame without performing the backoff operation when the short IFS (SIFS) has passed. In addition, when the arbitration IFS (AIFS) for the access category (AC) (i.e., AIFS [AC]) has passed, the quality of service (QoS) STA may send a frame after performing a backoff operation. In some embodiments, when the point coordination function (PCF) IFS (PIFS) has passed, the PCF-enabled AP STA may send a frame after performing a backoff operation. The PIFS duration may be less than the DIFS duration, but greater than the SIFS duration.

[0052] Figure 3 An example of OFDM symbols and OFDMA symbols according to an embodiment is shown. Figure 3 (a) and Figure 3 In (b), OFDM / OFDMA symbols are shown along the time dimension and subcarriers are shown along the frequency dimension.

[0053] OFDMA was introduced in the IEEE 802.11ax standard, which is also known as High-Efficiency (HE) WLAN. OFDMA will also be used in the next amendment to the IEEE 802.11 standard, such as Extremely High Throughput (EHT) WLAN. One or more STAs may be allowed to transmit data simultaneously using one or more resource units (RUs) over the entire operating bandwidth. A RU may be a set of subcarriers as an allocation of subcarriers for transmission. In some aspects, a non-AP STA may be associated or unassociated with an AP STA when a response frame is sent simultaneously in the allocated RU after a specific time period such as SIFS. SIFS may be the time from the end of the last symbol of the previous frame or the signal extension (if any) to the beginning of the first symbol of the preamble of the next frame.

[0054] OFDMA is a multiple access scheme based on OFDM, in which different subcarrier groups are assigned to different users, which allows transmission to one or more users at the same time, achieving high-precision frequency orthogonality synchronization. OFDMA allows users to be assigned different subcarrier groups in each PPDU (physical layer protocol data unit). Depending on the bandwidth of the PPDU, the OFDM symbol in OFDMA can include multiple subcarriers. The difference between OFDM and OFDMA is as follows Figure 3 As shown in Figure 3 As shown in (a), an OFDM symbol includes a single user (user A), while an OFDMA symbol includes multiple users (user A, user B, user C, and user D), and each user is assigned and allocated to a different subcarrier group, as shown in FIG. Figure 3 As shown in (b).

[0055] In the case of UL MU transmission, the AP STA can control the medium by allowing the AP STA and non-AP STA to use more scheduling access mechanisms of OFDMA and MU-MIMO. The non-AP STA can send a UL MU PPDU as a response to a trigger frame sent by the AP STA. The trigger frame may have information of the receiving STA and allocate a single or multiple RUs to the receiving STA. It allows the non-AP STA to send an OFDMA-based frame in the form of a trigger (TB)-based PPDU (e.g., HE TB PPDU or EHT TB PPDU), where the operating bandwidth is divided into multiple RUs and each RU is a response to the trigger frame. For the sake of simplicity of description, a single RU and multiple RUs (MRUs) allocated to a non-AP STA may be collectively referred to as RUs. In some embodiments, an MRU may indicate a combination of two RUs.

[0056] Figure 4A An example of a PPDU format according to an embodiment is shown. The PPDU may be used for both SU and MU transmissions. The PPDU may be used as an EHT MU PPDU compliant with IEEE 802.11be, or may be used as a PPDU compliant with any future revision of the IEEE 802.11 standard.

[0057] refer to Figure 4A, the EHT MU PPDU 40 may include an EHT preamble (which may be referred to as a preamble or a PHY preamble), a data field, and a packet extension (PE) field. The EHT preamble may include a pre-EHT modulation field and an EHT modulation field. The pre-EHT modulation field may include a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal (L-SIG) field, a repeated legacy signal (RL-SIG) field, a universal signal (U-SIG) field, and an EHT signal (EHT-SIG) field. The EHT modulation field may include an EHT short training field (EHT-STF) and one or more EHT long training fields (EHT-LTF).

[0058] The L-STF may be used for packet detection, automatic gain control (AGC), and coarse frequency offset correction. The L-LTF may be used for channel estimation, fine frequency offset correction, and symbol timing. The L-SIG field may provide information for communication, such as data rate, length associated with the EHT PPDU 40. The RL-SIG field may be a repetition of the L-SIG field and may be used to distinguish the EHT PPDU from other PPDUs that conform to other IEEE 802.11 standards such as IEEE 802.11a / n / ac. The U-SIG field may provide information required for the receiving STA to interpret the EHT MU PPDU. The EHT-SIG may provide additional information to the U-SIG field for the receiving STA to interpret the EHT MU PPDU 40. To simplify the description, the U-SIG field, the EHT-SIG field, or both may be referred to as SIG fields herein. The EHT-LTF may enable the receiving STA to estimate the MIMO channel between a set of constellation mapper outputs and a receive chain. The data field may carry one or more PHY service data units (PSDUs). The PE field may provide additional receive processing time at the end of the EHT MU PPDU.

[0059] Figure 4B Another example of a PPDU format according to an embodiment is shown. Figure 4B The PPDU in may be used for SU and MU transmissions. The PPDU 45 may be used as an EHT TB (trigger-based) PPDU compliant with IEEE 802.11be, or may be used as a PPDU compliant with any future amendment to the IEEE 802.11 standard. In some embodiments, the EHT TB PPDU 45 is used for transmission by a non-AP STA as a response to a trigger frame from an AP STA.

[0060] like Figure 4BAs shown, the EHT TB PPDU 45 may include an EHT preamble (which may be referred to as a preamble or a PHY preamble), a data field, and a packet extension (PE) field. The EHT preamble may include a pre-EHT modulation field and an EHT modulation field. The pre-EHT modulation field may include an L-STF field, an L-LTF field, an L-SIG field, an RL-SIG field, and a U-SIG field. The EHT modulation field may include an EHT-STF and one or more EHT-LTFs. Unlike the EHT MU PPDU 40, the EHT-SIG may not be present in the EHT TB PPDU 45. On the contrary, the duration (8us) of the EHT-STF of the EHT TB PPDU 45 may be twice the duration (4us) of the EHT-STF of the EHT MU PPDU 40. A detailed description of other fields in the EHT TB PPDU 45 will be omitted because the description of each field in the EHT MU PPDU 40 may be applied to each corresponding field of the EHT TB PPDU 45.

[0061] Figure 5 A schematic diagram showing an example of an electronic device according to an embodiment of the present invention is shown. The electronic device 50 may be Figure 1 An example of an AP STA 11 or a non-AP STA 12 is shown in FIG.

[0062] refer to Figure 5 , the electronic device 50 may include a processor 51, a memory 52, a transceiver 53 and an antenna unit 54. The transceiver 53 may include a transmitter 100 and a receiver 200.

[0063] The processor 51 may perform a medium access control (MAC) function, a PHY function, an RF function, or a combination of some or all of the foregoing functions. In some embodiments, the processor 51 may include part or all of the transmitter 100 and the receiver 200. The processor 51 may be directly or indirectly coupled to the memory 52. ​​In some embodiments, the processor 51 may include one or more processors.

[0064] The memory 52 may be a non-transitory computer-readable recording medium storing instructions that, when executed by the processor 51, cause the electronic device 50 to perform the operations, methods, or processes described in the present disclosure. In some embodiments, the memory 52 may store instructions required by one or more of the processor 51, the transceiver 53, and other components of the electronic device 50. The memory may also store operating systems and application programs. The memory 52 may include, be implemented as, or be included in a read-write memory, a read-only memory, a volatile memory, a non-volatile memory, or a combination of some or all of the foregoing.

[0065] Antenna unit 54 includes one or more physical antennas. When MIMO or MU-MIMO is used, antenna unit 54 may include more than one physical antenna.

[0066] Figure 6 A schematic diagram showing an example of a transmitter according to an embodiment is shown. Figure 6 The transmitter in can be Figure 5 An example of a transmitter is shown.

[0067] refer to Figure 6 , the transmitter 100 may include an encoder 101, an interleaver 103, a mapper 105, an inverse Fourier transformer (IFT) 107, a guard interval (GI) inserter 109 and an RF transmitter 111.

[0068] Encoder 101 can encode input data to generate encoded data. For example, encoder 101 can be a forward error correction (FEC) encoder. The FEC encoder can include or be implemented as a binary convolutional code (BCC) encoder or a low-density parity check (LDPC) encoder. Interleaver 103 can interleave the encoded data bits from encoder 101 to change the order of the bits, and output interleaved data. In some embodiments, when BCC encoding is adopted, interleaving can be applied. Mapper 105 can map interleaved data to constellation points to generate constellation point blocks. If LDPC encoding is used in encoder 101, mapper 105 can further perform LDPC tuning mapping instead of constellation mapping. IFT 107 can convert constellation point blocks into time domain blocks corresponding to symbols by using inverse discrete Fourier transform (IDFT) or inverse fast Fourier transform (IFFT). GI inserter 109 can preset GI into symbols. RF transmitter 111 can convert symbols into RF signals and send RF signals via antenna unit 34.

[0069] Figure 7 A schematic diagram showing an example of a receiver according to an embodiment is shown. Figure 7 The receiver in can be Figure 5 An example of a receiver is shown in .

[0070] refer to Figure 7, the receiver 200 according to the embodiment may include an RF receiver 201, a GI remover 203, a Fourier transformer (FT) 205, a demapper 207, a deinterleaver 209, and a decoder 211. The RF receiver 201 may receive an RF signal via an antenna unit 34 and convert the RF signal into one or more symbols. The GI remover 203 may remove the GI from the symbol. Depending on the implementation, the FT 205 may convert the symbol corresponding to the time domain block into a constellation point block by using a discrete Fourier transform (DFT) or a fast Fourier transform (FFT). The demapper 207 may demap the constellation point block to the demapped data bits. If LDPC coding is used, the demapper 207 may further perform LDPC tuning demapping before constellation demapping. The deinterleaver 209 may deinterleave the demapped data bits to generate deinterleaved data bits. In some embodiments, when BCC coding is used, deinterleaving may be applied. The decoder 211 may decode the deinterleaved data bits to generate decoded bits. For example, the decoder 211 may be a FEC decoder. The FEC decoder may include a BCC decoder or an LDPC decoder. To support the HARQ process, the decoder 211 may combine the retransmitted data with the initial data. The descrambler 213 may descramble the descrambled data bits based on the scrambler seed.

[0071] The IEEE 802.11be Extremely High Throughput (EHT) Task Group is developing the next generation of Wi-Fi standards to achieve higher data rates, lower latency, and more reliable connections for an enhanced user experience. One of the key features of Wi-Fi 7 is Multi-Link Operation (MLO). Since most current APs and base stations (STAs) contain dual-band or tri-band capabilities, the newly developed MLO feature can achieve packet-level link aggregation across different PHY links at the MAC layer. By performing load balancing based on traffic requirements, MLO achieves significantly higher throughput and lower latency, thereby enhancing reliability in heavily loaded networks. With the MLO capability, a multi-link device (MLD) can incorporate multiple "attached" devices into the upper logical link control (LLC) layer, so that data can be sent and received concurrently across multiple channels in a single or multiple frequency bands of 2.4GHz, 5GHz, and 6GHz. Figure 8An MLO operation with two links is shown. As shown, the AP MLD includes attached AP 1 and AP2, and the non-AP MLD includes attached STA 1 and STA 2. AP1 is associated with STA 1 on link 1, and AP 2 is associated with STA 2 on link 2. As shown, AP 1 can send a data frame to STA 1 via link 1, STA 1 can send an acknowledgment frame to AP 1 via link 1 in response to the data frame, STA 2 can send a data frame to AP 2 via link 2, and AP 2 can send an acknowledgment frame to STA 2 via link 2 in response to the data frame. AP MLD and non-AP MLD can simultaneously transmit and receive in link 1 and link 2.

[0072] Existing Wi-Fi technology allows devices to connect to a single link and be able to switch between the 2.4GHz, 5GHz, and 6GHz bands. However, such Wi-Fi devices typically have a switching overhead or latency of up to 100 milliseconds. Therefore, MLO is ideal for real-time applications such as video calls, wireless VR headsets, cloud gaming, and other delay-sensitive applications. The IEEE802.11be draft specification defines different channel access methods based on two transmission modes: asynchronous and synchronous mode. In asynchronous transmission mode, MLD transmits frames asynchronously across multiple links without aligning the start time of the frames. In contrast, synchronous transmission mode aligns the start time of frame transmission across links. In both modes, a link can have its own primary channel and parameters, including packet protocol data unit (PPDU), modulation and coding scheme (MCS), enhanced distributed channel access (EDCA), etc.

[0073] As wireless systems become more prevalent and develop, applications that require the use of low-latency traffic to provide appropriate functionality are being developed and commercialized. As mentioned above, these applications can include virtual reality / augmented reality (VR / AR), which ingest real-time data from different sources to provide visualizations. Other applications can include immersive gaming, teleworking, and cloud computing, as well as a variety of other applications that require more challenging time-sensitive technologies. As a result, various technologies are currently being developed to support low-latency traffic.

[0074] The technology of STA moving from one basic service set (BSS) to another BSS is a long-standing problem that has been addressed by various solutions. In Wi-Fi systems, the fast transition (FT) protocol can solve this problem. However, due to the authentication and reassociation process (with additional delays), wireless systems may still experience interruptions in sending and / or receiving data during roaming.

[0075] Thus, some embodiments provide enhanced roaming that reduces data transmission delays.

[0076] Current roaming technologies may have various problems. Fig. 9 In the configuration of , when the link with AP 1 deteriorates and the signal with AP 2 becomes stronger, the STA roams to AP 2, and then the STA re-associates with AP 2 (e.g., over-the-air situation in fast transition (FT)). After successful establishment and authentication, the STA negotiates some protocols with AP 2, such as block acknowledgement (BA) protocol and / or security protocol.

[0077] Therefore, when a STA roams between multiple APs, the STA needs to reassociate with the target AP and perform a 4-way handshake in FT, and the network needs to switch the data path in a break-before-make manner, which results in data interruption and additional delay during roaming.

[0078] Many implementations address these issues with current roaming techniques, where the context of association, authentication, and BA protocols need to be maintained, and a data path needs to be enabled to exchange frames during roaming.

[0079] Some embodiments provide enhanced roaming based on MLO and can leverage the existing MLO framework.

[0080] MLO defined in IEEE 802.11be already allows non-AP MLDs to switch links with minimal signaling overhead and latency.

[0081] Therefore, many implementations provide seamless roaming to another AP based on MLO with minimal communication disruption.

[0082] In some embodiments, there is a wireless communication device that supports multi-link operation (MLO), which can be defined as a multi-link device (MLD). Both APs and STAs can have MLD capabilities. An AP that supports MLO can be referred to as an AP MLD, and a STA that supports MLO can be referred to as a non-AP MLD. There are many AP MLDs that can communicate with each other.

[0083] Before roaming operation, each AP MLD may operate its own BSS. Fig.10 An example of normal MLD operation according to an embodiment is shown. Specifically, each AP MLD can operate its own BSS. STA 1 and STA 2 are affiliated to non-AP MLD a and are associated with AP 1 and AP 2, respectively, which are affiliated to AP MLD A. STA 3 and STA 4, which are affiliated to non-AP MLD b, are associated with AP 3 and AP 4, respectively, which are affiliated to AP MLD B.

[0084] To implement roaming operation, one of these AP MLDs may be a roaming AP MLD.

[0085] The roaming AP MLD may be determined based on information exchanged between AP MLDs. This information may relate to the current traffic status and buffer capacity of each AP MLD, among other types of information.

[0086] Some embodiments may include various procedures for roaming AP MLD setup. Fig.11 A roaming AP MLD setup according to an embodiment is shown. AP 1 and AP 2 are affiliated to AP MLD A, and AP 3 and AP 4 are affiliated to AP MLD B. STA 1 and STA 2 are affiliated to non-AP MLD a, and STA 3 and STA 4 are affiliated to non-AP MLD b. AP MLD A is associated with non-AP MLD a, and AP MLD B is associated with non-AP MLD b. AP MLD A may send one or more beacon frames to AP MLD B, and MLD B may send one or more beacon frames to AP MLD A. For AP MLD A, the beacon frame may be sent by AP 1 and / or AP 2. For AP MLD B, the beacon frame may be sent by AP 3 and / or AP 4.

[0087] The beacon frame may include information that informs other nearby AP MLDs that the AP MLD sending the beacon frame has the capability to support roaming operations and may be a candidate for roaming AP MLD. The information may include traffic status and buffer capacity as well as other types of information.

[0088] Some embodiments may compare the stacked traffic of the buffer in AP MLD A with the stacked traffic in AP MLD B, and the AP MLD with the larger buffer size or smaller stacked traffic may become the roaming AP MLD.

[0089] In some embodiments, a roaming AP MLD may form a new affiliation with an AP that is affiliated with another AP MLD.

[0090] Fig.12 It is shown that if AP MLD A becomes a roaming AP MLD, AP 3 and AP 4 affiliated with AP MLD B should form a new affiliation with AP MLD A. Therefore, APs 1 and 2 collocated with AP MLD A and APs 3 and 4 not collocated can all be affiliated with the roaming AP MLD.

[0091] In some embodiments, if the non-AP MLD supports roaming, a BA protocol is negotiated between the STA affiliated with the non-AP MLD and AP 1, AP 2, AP 3, or AP 4 affiliated with the roaming AP MLD. The context of association, security, and BA session can be maintained between the roaming AP MLD and the non-AP MLD.

[0092] Now described is the operation of a STA affiliated with a non-AP MLD to support roaming. In some embodiments, before the roaming mode, the non-AP MLD may perform an association with an AP affiliated with an AP MLD. Fig.10 As shown, if the number of links supported in the AP MLD is 2, the non-AP MLD forms an association for the two links.

[0093] Fig.13 A roaming mode setting according to an embodiment is shown. As shown, during the roaming mode setting, STA 1 and STA 2 attached to non-AP MLD a can be associated with AP MLD A. When AP MLD A becomes a roaming AP MLD, STA 1 and STA 2 receive additional information of links corresponding to AP 3 and AP 4 attached to AP MLD B. In some embodiments, STA 1 and STA 2 can receive frames (e.g., probe response frames, etc.) including additional information from AP 1 and / or AP 2. In some embodiments, STA 1 and STA 2 can receive frames (e.g., probe response frames, etc.) including additional information from AP 3 and / or AP 4. STA 1 and STA 2 attached to non-AP MLD a do not need to form an association with AP MLD A because the association has been previously formed.

[0094] Fig.14 The roaming mode setting according to the implementation scheme is shown. As shown in the figure, AP 1 and AP 2 are attached to AP MLD A, and AP 3 and AP 4 are attached to AP MLD B. STA 3 and STA 4 are attached to non-AP MLD b associated with AP MLD B. When AP MLD A becomes a roaming AP MLD, STA 3 and STA 4 form a new association with AP MLD A (roaming AP MLD), including authentication, security, BA protocol, etc. STA 3 and STA 4 attached to non-AP MLD b need to form an association with AP MLD A because the association has not yet been formed.

[0095] The information exchanged between non-AP MLD b and AP MLD A (roaming AP MLD) during association includes additional information of AP 1 and AP 2. Therefore, AP3 and AP4 are non-collocated with AP MLD A and are subordinate to AP MLD A.

[0096] After the described roaming setup, roaming operation can be enabled.

[0097] Figures 15 to 17 Configurations before, during, and after roaming setup according to an embodiment are shown.

[0098] Fig.15 The configuration before roaming according to the implementation scheme is shown. As shown in the figure, AP MLD A includes AP1 and AP2 co-located with AP MLD A and subordinate to AP MLD A, and AP3 and AP 4 non-co-located with AP MLD A and subordinate to AP MLD A. STA 1 and STA 2 are subordinate to non-AP MLD a. STA 1 in non-AP MLD a is active for AP 1 in AP MLD A, and the data path is routed to AP 1 in AP MLD A. AP 1 can host the context of AP MLD A (roaming AP MLD) for the client.

[0099] Fig.16 The configuration during roaming according to an embodiment is shown. STA 1 in non-AP MLD a is active for both AP 1 and AP 3 in roaming APMLD.

[0100] Fig.17 The configuration after roaming according to the embodiment is shown. Specifically, STA 1 in non-AP MLD a is no longer active with respect to AP 1 in roaming AP MLD. The data path is rerouted to AP 3 in roaming AP MLD. AP 3 saves the context of roaming AP MLD for the client.

[0101] Fig.18 A ladder diagram for configuring roaming between AP MLDs according to an embodiment is shown. At 1801, AP MLD A may send a beacon frame to AP MLD B. At 1803, AP MLD B may send a beacon frame to AP MLD A. The beacon frame may include information about the current traffic state and / or buffer capacity of the AP MLD. In some embodiments, the beacon frame may be sent by an AP affiliated with the AP MLD. The beacon frame may include information notifying other nearby AP MLDs that the AP MLD sending the beacon frame has the capability to support roaming operations and may be a candidate for a roaming AP MLD.

[0102] AP MLD A determines that it is a roaming AP MLD at 1805. In some embodiments, the determination may be made by comparing the stack flow of the buffer in AP MLD A with the stack flow in AP MLD B, and the AP MLD with the larger buffer size and / or smaller stack flow may become the roaming AP MLD.

[0103] At 1807, AP MLD A forms a new affiliation with a non-collocated AP that is affiliated with other AP MLD B.

[0104] At 1809 , the non-AP MLD determines whether it is associated with AP MLD A.

[0105] If at 1809, the non-AP MLD determines that it is not associated with AP MLD A, the non-AP MLD performs operations 1811, 1813, 1815, and 1817. Specifically, at 1811, the non-AP MLD receives additional information about an AP affiliated with AP MLD A. At 1813, the non-AP MLD associates with AP MLD A based on the received additional information, including authentication, security, and / or BA protocols. At 1815, the non-AP MLD performs roaming from an AP affiliated with AP MLD B to an AP affiliated with AP MLD A based on the received additional information. At 1817, the non-AP MLD communicates with AP MLD A.

[0106] If the non-AP MLD determines that it is associated with AP MLD A at 1809, the non-AP MLD performs operations 1819, 1821, and 1823. Specifically, at 1819, the non-AP MLD receives additional information about an AP affiliated with AP MLD B. At 1821, the non-AP MLD performs roaming from an AP affiliated with AP MLD A to an AP affiliated with AP MLD B based on the received additional information. At 1823, the non-AP MLD communicates with AP MLD B.

[0107] Fig.19 A flowchart of an example process for roaming between MLDs according to an embodiment is shown. In process 1900, in operation 1901, the STA is active for an AP affiliated with AP MLD A. In operation 1903, the STA is active for both the AP affiliated with AP MLD A and the AP affiliated with AP MLD B during roaming. In operation 1905, the STA is active only for the AP affiliated with AP MLD B after roaming.

[0108] To illustrate the interchangeability of hardware and software, items such as various example blocks, modules, components, methods, operations, instructions, and algorithms have been generally described in terms of their functions. Whether these functions are implemented in the form of hardware or software depends on the specific application and the design constraints on the overall system. A skilled person may implement the described functions in different ways for each specific application.

[0109] Unless otherwise specified, reference to a singular element does not mean one and only one, but rather one or more. For example, "a" module may refer to one or more modules. Without further limitation, an element beginning with "a", "an", "the" or "said" does not exclude the presence of other identical elements.

[0110] Headings and subheadings, if any, are used for convenience only and do not limit the invention. The word "exemplary" is used to mean serving as an example or illustration. To the extent that the terms "including," "having," or similar terms are used, such terms are intended to be inclusive in a manner similar to the term "comprising," which when used as a transitional term in a claim is interpreted as "comprising." Relational terms such as first and second, etc., may be used to distinguish one entity or action from another without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0111] The following phrases, such as an aspect, the aspect, another aspect, some aspects, one or more aspects, an implementation, the implementation, another implementation, some implementations, one or more implementations, an embodiment, the embodiment, another embodiment, some embodiments, one or more embodiments, a configuration, the configuration, another configuration, some configurations, one or more configurations, subject technology, the present invention, the present invention and other variations, etc., are for convenience and do not mean that the disclosure associated with these phrases is essential to the subject technology, nor does it mean that such disclosure applies to all configurations of the subject technology. The disclosure associated with these phrases can apply to all configurations, or one or more configurations. The disclosure associated with these phrases can provide one or more examples. Phrases such as an aspect or some aspects can refer to one or more aspects, and vice versa, and the same applies to the other aforementioned phrases.

[0112] The phrase "at least one" preceding a list of items, with the terms "and" or "or" separating one or more of those items, modifies the entire list, rather than each member of the list. The phrase "at least one" does not require selection of at least one item; rather, the phrase permits meanings that include at least one of any one item, and / or at least one of any combination of items, and / or at least one of each item. For example, each of the phrases "at least one of A, B, and C" or "at least one of A, B, or C" refers to A only, B only, or C only; any combination of A, B, and C; and / or at least one of each of A, B, and C.

[0113] It should be understood that the specific order or hierarchy of the disclosed steps, operations or processes is an illustration of an exemplary method. Unless otherwise explicitly stated, it should be understood that the specific order or hierarchy of steps, operations or processes can be performed in different orders. Some steps, operations or processes can be performed simultaneously, or can be performed as part of one or more other steps, operations or processes. The attached method claims (if any) present the elements of various steps, operations or processes in a sample order and are not meant to be limited to the specific order or hierarchy presented. These can be performed in serial, linear, parallel or different orders. It should be understood that the instructions, operations and systems described can generally be integrated together in a single software / hardware product, or packaged into multiple software / hardware products.

[0114] The disclosure is provided to enable any person skilled in the art to practice the various aspects described herein. In some cases, in order to avoid blurring the concept of the subject technology, well-known structures and components are shown in block diagram form. The disclosure provides various examples of the subject technology, and the subject technology is not limited to these examples. Various modifications to these aspects are apparent to those skilled in the art, and the principles described herein may be applied to other aspects.

[0115] All structural and functional equivalents to the elements of the various aspects described in this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated into this disclosure by reference and are intended to be covered by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is expressly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in a method claim, using the phrase “step for.”

[0116] The title of the invention, background technology, description of the figures, abstract of the specification and drawings are hereby incorporated into the present disclosure and serve as illustrative examples of the present disclosure, rather than restrictive descriptions. It should be understood that these contents will not be used to limit the scope or interpretation of the claims. In addition, in the specific embodiments, it can be seen that the description provides illustrative examples, and various features are combined together in various implementations for the purpose of simplifying the present disclosure. This method of disclosure should not be interpreted as reflecting the intention that the claimed subject matter requires more features than the features explicitly stated in each claim. On the contrary, as reflected in the following claims, the creative subject matter lies in fewer features than all the features of a single disclosed configuration or operation. The following claims are hereby included in the specific description, and each claim exists independently as a separately claimed subject matter.

[0117] The claims are not intended to limit the aspects described herein, but rather should be given the full scope consistent with the claim language and including all legal equivalents. Nevertheless, no claim is intended to encompass subject matter that is inconsistent with applicable patent law requirements, nor should it be interpreted in such a manner.

Claims

1. A first access point multi-link device AP MLD for connecting to a wireless network, the first AP MLD comprising: one or more APs attached to the first AP MLD, including the first AP; a processor coupled to the first AP, the processor being configured to: communicating with a second AP MLD to determine that the first AP MLD is a roaming AP MLD; forming an affiliated relationship with a second AP among the one or more non-collocated APs affiliated with the second AP MLD; sending information about the first AP attached to the first AP MLD to a non-AP MLD associated with the second AP MLD; being associated with the non-AP MLD; and After the non-AP MLD performs roaming from the second AP MLD to the first AP MLD, communicating with the non-AP MLD via the first AP MLD.

2. The first AP MLD according to claim 1, wherein: Communicating with the second AP MLD to determine that the first AP MLD is the roaming AP MLD includes: receiving a frame from the second AP MLD, the frame including information for determining which AP MLD can become the roaming AP MLD; and It is determined based on information in the frame that the first AP MLD is the roaming AP MLD.

3. The first AP MLD according to claim 2, wherein: The frame is a beacon frame.

4. The first AP MLD according to claim 2, wherein: The frame includes traffic state information of the second AP MLD.

5. The first AP MLD according to claim 4, wherein: Determining that the first AP MLD is the roaming AP MLD includes: comparing the stack flow of the first AP MLD with the stack flow indicated by the flow state information of the second AP MLD, and If the stack flow rate of the first AP MLD is smaller than the stack flow rate indicated by the flow status information of the second AP MLD, it is determined that the first AP MLD is the roaming AP MLD.

6. The first AP MLD according to claim 2, wherein: The frame includes buffer capacity information of the second AP MLD.

7. The first AP MLD according to claim 6, wherein: Determining that the first AP MLD is the roaming AP MLD includes: comparing the buffer size of the first AP MLD with the buffer size indicated by the buffer capacity information of the second AP MLD, and If the buffer size of the first AP MLD is greater than the buffer size indicated by the buffer capacity information of the second AP MLD, it is determined that the first AP MLD is the roaming AP MLD.

8. The first AP MLD according to claim 1, wherein: Associating with the non-AP MLD includes performing at least one of an authentication, security, and block validation protocol with the non-AP MLD.

9. A non-access point multi-link device AP MLD for connecting to a wireless network, comprising a processing circuit, wherein the processing circuit is configured to: Associating with the first AP attached to the first AP MLD; communicating with the first AP attached to the first AP MLD; receiving information about the second AP MLD; associating with a second AP that is subordinate to the second AP MLD and the first AP MLD, wherein the first AP and the second AP are not collocated; performing roaming from the first AP attached to the first AP MLD to the second AP attached to the second AP MLD; and Communicate with the second AP affiliated with the second AP MLD.

10. The non-AP MLD of claim 9, wherein the processing circuit is further configured to associate with the second AP affiliated with the second AP MLD by performing at least one of authentication, security, and block confirmation protocols with the second AP MLD.

11. The non-AP MLD of claim 9, wherein the processing circuit is further configured to be active for both the first AP affiliated with the first AP MLD and the second AP affiliated with the second AP MLD during roaming.

12. The non-AP MLD of claim 11, wherein the processing circuit is further configured to be active only for the second AP affiliated with the second AP MLD after roaming.

13. A computer-implemented method for facilitating communications in a wireless network, the method comprising: A first AP attached to a first access point multi-link device AP MLD communicates with a second AP MLD to determine that the first AP MLD is a roaming AP MLD; forming an affiliated relationship with a second AP among the one or more non-collocated APs affiliated with the second AP MLD; sending information about the first AP attached to the first AP MLD to a non-AP MLD associated with the second AP MLD; being associated with the non-AP MLD; and After the non-AP MLD performs roaming from the second AP MLD to the first AP MLD, communicating with the non-AP MLD via the first AP MLD.

14. The computer-implemented method of claim 13, wherein: Communicating with the second AP MLD to determine that the first AP MLD is the roaming AP MLD includes: receiving a frame from the second AP MLD, the frame including information for determining which AP MLD can become the roaming AP MLD, and It is determined based on information in the frame that the first AP MLD is the roaming AP MLD.

15. The computer-implemented method of claim 14, wherein: The frame is a beacon frame.

16. The computer-implemented method of claim 14, wherein: The frame includes traffic state information of the second AP MLD.

17. The computer-implemented method of claim 16, wherein: Determining that the first AP MLD is the roaming AP MLD includes: comparing the stack flow of the first AP MLD with the stack flow indicated by the flow state information of the second AP MLD, and If the stack flow rate of the first AP MLD is smaller than the stack flow rate indicated by the flow status information of the second AP MLD, it is determined that the first AP MLD is the roaming AP MLD.

18. The computer implemented method of claim 14, wherein the frame includes buffer capacity information of the second AP MLD.

19. The computer-implemented method of claim 18, wherein: Determining that the first AP MLD is the roaming AP MLD includes: comparing the buffer size of the first AP MLD with the buffer size indicated by the buffer capacity information of the second AP MLD, and If the buffer size of the first AP MLD is greater than the buffer size indicated by the buffer capacity information of the second AP MLD, it is determined that the first AP MLD is the roaming AP MLD.

20. The computer-implemented method of claim 13, wherein: Associating with the non-AP MLD includes performing at least one of an authentication, security, and block validation protocol with the non-AP MLD.

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