CN117693063A

CN117693063A - Access point multilink device and non-access point multilink device

Info

Publication number: CN117693063A
Application number: CN202311014117.0A
Authority: CN
Inventors: 朴成珍; 金大弘
Original assignee: Senscomm Semiconductor Co Ltd
Current assignee: Senscomm Semiconductor Co Ltd
Priority date: 2022-09-07
Filing date: 2023-08-11
Publication date: 2024-03-12

Abstract

An access point multilink device and a non-access point multilink device are provided. The access point multilink device is associated with a non-access point multilink device. The non-access point multilink device includes a first station and a second station. The access point multilink device includes: a first access point attached to the access point multilink device and associated with the first station; and a second access point attached to the access point multilink device and associated with the second station. The first access point establishes a first link with the first station and the second access point establishes a second link with the second station. The first link uses a millimeter wave band and the second link uses a frequency band below the millimeter wave band. When the second link is enabled, the first access point transmits a beamforming training signal for the first link to the first station and receives beamforming feedback information from the first station.

Description

Access point multilink device and non-access point multilink device

Technical Field

The present disclosure relates to wireless communication systems, and more particularly, to (e.g., but not limited to) wireless communication devices for low latency.

Background

Wireless Local Area Networks (WLANs) continue to evolve and have become an important technology for providing wireless data services in different environments. In addition to increasing throughput and overall efficiency requirements as an emerging and tremendous potential use case, high reliability and low latency are also contemplated. Examples of such use cases are Virtual Reality (VR) and Augmented Reality (AR), immersive gaming, teleoffice, and cloud computing. These situations require more challenging time-sensitive techniques.

The description set forth in the background section is not intended to be construed as prior art only because it is set forth in the background section. The background section may describe aspects or embodiments of the present disclosure.

Disclosure of Invention

Embodiments allow an electronic device to facilitate wireless communications. More specifically, embodiments allow wireless local area networks and wireless devices to improve throughput and reduce latency.

One aspect of the present disclosure may provide an Access Point (AP) multilink device (MLD) associated with a non-access point multilink device comprising a first Station (STA) and a second station, the access point multilink device comprising: a first access point attached to the access point multilink device and associated with the first station; and a second access point attached to the access point multilink device and associated with the second station, wherein the first access point establishes a first link with the first station, the second access point establishes a second link with the second station, the first link uses a millimeter-wave band, the second link uses a frequency band below the millimeter-wave band, and when the second link is enabled, the first access point transmits a beamforming training signal for the first link to the first station and receives beamforming feedback information from the first station. The second access point transmits a beamforming training request for the first link to the second station over the second link.

The beamforming training request may include beamforming training information for the first link.

The beamforming training information may include a start time of a beamforming training procedure for the first link.

The first access point may begin a beamforming training procedure at a start time.

The second station may send beamforming training information to the first station and the first station wakes up at a start time.

The first access point may receive beamforming feedback information from a second access point, which receives beamforming feedback information from a second station via a second link.

The beamforming training signal may include a Medium Access Control (MAC) address of the first station.

The beamforming training signal may include a broadcast address.

The first access point may transmit a beamforming training signal for the first link to the first station while the second access point exchanges data frames with the second station.

One aspect of the disclosure may provide a non-Access Point (AP) multilink device (MLD) associated with an access point multilink device comprising a first access point and a second access point, the non-access point multilink device comprising: a first Station (STA) affiliated with the non-access point multi-link device and associated with the first access point; and a second station attached to the non-access point multilink device and associated with the second access point,

Wherein the first station establishes a first link with the first access point, the second station establishes a second link with the second access point, the first link uses a millimeter wave band, the second link uses a frequency band below the millimeter wave band, and when the second link is enabled, the first station receives a beamforming training signal for the first link from the first access point and sends beamforming feedback information to the first access point.

The second station may receive a beamforming training request for the first link from the second access point via the second link.

The first station may begin the beamforming training procedure at a start time.

The first station may transmit beamforming feedback information to the second station, wherein the second station transmits the beamforming feedback information to the second access point over the second link.

The beamforming training signal may include a broadcast address.

The first station may receive a beamforming training signal for the first link from the first access point while the second station exchanges data frames with the second access point.

If the control field indicates that the physical layer preamble in the physical layer protocol data unit includes Medium Access Control (MAC) information and the physical layer protocol data unit does not carry a data field, the payload information may include a physical layer protocol data unit type field.

Drawings

Fig. 1 shows a schematic diagram of an example wireless communication network.

Fig. 2 shows an example of a timing diagram of an inter-frame space (IFS) relationship between stations according to an embodiment.

Fig. 3 shows OFDM symbols and OFDMA symbols according to an embodiment.

Fig. 4A illustrates an EHT MU PPDU format according to an embodiment.

Fig. 4B illustrates an EHT TB PPDU format according to an embodiment.

Fig. 5 is a block diagram of an electronic device for facilitating wireless communications according to an embodiment.

Fig. 6 shows a block diagram of a transmitter according to an embodiment.

Fig. 7 shows a block diagram of a receiver according to an embodiment.

Fig. 8 illustrates a block diagram including an access point multilink device and a non-access point multilink device for exemplary multilink operation according to an embodiment.

Fig. 9 illustrates a multilink operation with two links according to an embodiment.

Fig. 10 illustrates a block diagram including an access point multilink device supporting a millimeter-wave band and a non-access point multilink device according to an embodiment.

Fig. 11 illustrates a conceptual beam formed between two stations according to an embodiment.

Fig. 12 is a ladder diagram illustrating a beamforming training procedure according to an embodiment.

Fig. 13 is a conceptual diagram illustrating a beamforming training procedure according to an embodiment.

Fig. 14 is a ladder diagram illustrating a beamforming training procedure according to an embodiment.

Fig. 15 is a ladder diagram illustrating a beamforming training procedure according to an embodiment.

Fig. 16 is a conceptual diagram illustrating a beamforming training procedure according to an embodiment.

Fig. 17 is a ladder diagram illustrating a fast beamforming training procedure according to an embodiment.

Detailed Description

The detailed description set forth below is intended to describe various embodiments and is not intended to represent the only embodiments. As those skilled in the art will appreciate, the described embodiments may be modified in various different ways, all without departing from the scope of the present disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive. Like reference numerals designate like elements.

The following detailed description herein has been described with reference to wireless LAN systems in accordance with 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 recognize that the teachings herein are applicable to other network environments, such as cellular telecommunication networks and wired telecommunication networks.

In some embodiments, devices or apparatuses, such as AP STAs and non-APs, may include one or more hardware and software logic structures for performing one or more operations described herein. For example, the apparatus or device may include at least one memory unit storing instructions executable by a hardware processor installed in the apparatus and at least one processor configured to perform operations or processes described in the present disclosure. The apparatus may also include one or more other hardware or software elements, such as a network interface and a display device.

Fig. 1 shows a schematic diagram of an example wireless communication network.

Referring to fig. 1, a Basic Service Set (BSS) 10 may include a plurality of Stations (STAs) including an Access Point (AP) station (AP STA) 11 and one or more non-AP stations (non-AP STA) 12. The STA may share the same radio frequency channel with one of the WLAN operating bandwidth options (e.g., 20/40/80/160/320 MHz). Hereinafter, in some embodiments, an AP STA and a non-AP STA may be referred to as an AP and a STA, respectively. In some embodiments, AP STAs and non-AP STAs may be collectively referred To As Stations (STAs).

Multiple STAs may participate in a multi-user (MU) transmission. In the MU transmission, the AP STA 11 may simultaneously transmit downlink frames to the plurality of non-AP STAs 12 in the BSS10 based on different resources, and the plurality of non-AP STAs 12 may simultaneously transmit uplink frames to the AP STAs 11 in the BSS10 based on different resources.

For MU transmissions, multi-user multiple-input multiple-output (MU-MIMO) transmissions or Orthogonal Frequency Division Multiple Access (OFDMA) transmissions may be used. In MU-MIMO transmission, multiple non-AP STAs 12 may transmit simultaneously to the AP STA 11 or receive separate data streams simultaneously from the AP STA 11 on the same subcarrier through one or more antennas. Different frequency resources may be used as different resources in the MU-MIMO transmission. In OFDMA transmission, multiple non-AP STAs 12 may transmit simultaneously to the AP STA 11 or receive separate data streams simultaneously from the AP STA 11 on different subcarrier sets. Different spatial streams may be used as different resources in MU-MIMO transmission.

In particular, fig. 2 shows a CSMA (carrier sense multiple access)/CA (collision avoidance) based frame transmission procedure for avoiding collision between frames in a channel.

Data frames, control frames, or management frames may be exchanged between STAs.

The data frames may be used to transmit data that is forwarded to higher layers. Referring to fig. 2, when the medium is busy, access is deferred until one type of IFS duration has elapsed. If the distributed coordination function IFS (DIFS) has elapsed since the time the medium is idle, the STA may transmit a data frame after performing backoff (backoff).

The management frame may be used to exchange management information that is not forwarded to higher layers. Subtype frames of the management frame may include beacon frames, association request/response frames, probe request/response frames, and authentication request/response frames.

The control frame may be used to control access to the medium. Subtype frames of control frames include Request To Send (RTS) frames, clear To Send (CTS) frames, and Acknowledgement (ACK) frames. In the case where the control frame is not a response frame of another frame, if the DIFS has passed, the STA may transmit the control frame after performing backoff. If the control frame is a response frame of a previous frame, the WLAN device may transmit the control frame without performing backoff when a Short IFS (SIFS) is passed. The type and subtype of a frame may be identified by a type field and a subtype field in a frame control field.

On the other hand, if the Arbitration IFS (AIFS) of the Access Class (AC), i.e., AIFS [ AC ], has passed, the quality of service (QoS) STA may transmit a frame after performing backoff. In this case, a data frame, a management frame, or a control frame (not a response frame) may use AIFC [ AC ].

In some embodiments, an AP STA that enables a Point Coordination Function (PCF) may send a frame after performing a backoff if the PCF IFS (PIFS) has passed. The PIFS duration may be less than DIFS but greater than SIFS.

Fig. 3 shows OFDM symbols and OFDMA symbols according to an embodiment.

For multi-user access modulation, orthogonal Frequency Division Multiple Access (OFDMA) for uplink and downlink has been introduced in the IEEE 802.11ax standard known as high-efficiency (HE) WLAN, and will be used for future revisions of 802.11, such as EHT (very high throughput). One or more STAs may be allowed to transmit data simultaneously using one or more Resource Units (RUs) throughout the operating bandwidth. As a minimum granularity, one RU may include a predefined number of subcarriers and be located at predefined locations in an Orthogonal Frequency Division Multiplexing (OFDM) modulation symbol. Here, the non-AP STA may or may not be associated with the AP STA when simultaneously responding in the allocated RU within a specific period such as a Short Inter Frame Space (SIFS). SIFS may refer to the duration from the end of the last symbol of the previous frame or signal extension (if present) to the beginning of the first symbol of the preamble of the next frame.

OFDMA is an OFDM-based multiple access scheme in which different subsets of subcarriers may be allocated to different users, allowing simultaneous transmission of data to or from one or more users with high accuracy synchronization of frequency orthogonality. In OFDMA, users may be allocated a subset of different subcarriers that may change from one physical layer (PHY) protocol data unit (PPDU) to the next. In OFDMA, an OFDM symbol is composed of subcarriers, the number of which is a function of the PPDU bandwidth. The difference between OFDM and OFDMA is shown in fig. 3.

In the case of UL MU transmissions, an AP STA may want to have more medium control mechanisms by using more scheduled accesses, which may allow more frequent use of OFDMA/MU-MIMO transmissions, given the different STAs with their own capabilities and characteristics. The PPDU in UL MU transmissions (MU-MIMO or OFDMA) may be sent as a response to a trigger frame sent by the AP. The trigger frame may have information of the STA and allocate RU and Multiple RUs (MRUs) to the STA. The information of the STA in the trigger frame may include a STA Identification (ID), MCS (modulation and coding scheme), and frame length. The trigger frame may allow the STA to transmit a trigger-based (TB) PPDU (e.g., an HE TB PPDU or an EHT TB PPDU) divided into RUs, and all RUs as a response of the trigger frame are allocated to the requested non-AP STA accordingly. Hereinafter, the single RU and the plurality of RUs may be referred to as RUs. The plurality of RUs may include or consist of two, three, or more RUs that are predefined.

In the EHT revision, two EHT PPDU formats are defined: EHT MU PPDU and EHT TB PPDU. Hereinafter, the EHT MU PPDU and the EHT TB PPDU will be described with reference to fig. 4A and 4B.

Fig. 4A illustrates an EHT MU PPDU format according to an embodiment.

The EHT MU PPDU may be used for transmission to one or more users. The EHT MU PPDU is not a response to a trigger frame.

Referring to fig. 4a, the EHT MU PPDU may include or consist of an EHT preamble (hereinafter, referred to as a PHY preamble or preamble), a data field, and a Packet Extension (PE) field. The EHT preamble may include or consist of a front EHT modulation field and an EHT modulation field. The front EHT modulation field may include or consist of a non-HT short training field (L-STF), a non-HT long training field (L-LTF), a non-HT signal (L-SIG) field, a repeated non-HT signal (RL-SIG) field, a universal signal (U-SIG) field, and an EHT signal (EHT-SIG) field. The EHT modulation field may include or consist of an EHT short training field (EHT-STF) and an EHT long training field (EHT-LTF). In some embodiments, the L-STF may be followed by an L-LTF, followed by an L-SIG field, followed by an RL-SIG field, followed by a U-SIG field, followed by an EHT-STF field, followed by an EHT-LTF field, followed by a data field, and followed by a PE field.

The L-STF field may be used for packet detection, automatic Gain Control (AGC), and coarse frequency offset correction.

The L-LTF field may be used for channel estimation, fine frequency offset correction, and symbol timing.

The L-SIG field may be used to transmit rate and length information.

The RL-SIG field may be a repetition of the L-SIG field and may be used to distinguish EHT PPDUs from non-HT PPDUs, and VHT PPDUs.

The U-SIG field may carry information necessary to interpret the EHT PPDU.

The EHT-SIG field may provide additional signaling for the U-SIG field to interpret the EHT MU PPDU by the STA. Hereinafter, the U-SIG field, the EHT-SIG field, or both may be referred to as a SIG field.

The EHT-SIG field may include one or more EHT-SIG content channels. Each of the one or more EHT-SIG content channels may include a common field and a user-specific field. The common field may contain information about the resource unit allocation, such as RU allocation to be used in the EHT modulation field of the PPDU, RU allocated to MU-MIMO, and the number of users in the MU-MIMO allocation. The user-specific fields may include one or more user fields.

The user fields of the non-MU MIMO allocation may include a STA-ID subfield, an MCS subfield, an NSS subfield, a beamforming subfield, and a coding subfield. The user fields for MU-MIMO allocation may include a STA-ID subfield, an MCS subfield, a coding subfield, and a spatial configuration subfield.

The EHT-STF field may be used to improve automatic gain control estimation in MIMO transmissions.

The EHT-LTF field may enable a receiver to estimate a MIMO channel between a set of constellation mapper outputs and a receive chain.

The data field may carry one or more Physical Layer Convergence Procedure (PLCP) service data units (PSDUs).

The PE field may provide additional receive processing time at the end of the EHT MU PPDU.

Fig. 4B illustrates an EHT TB PPDU format according to an embodiment.

The EHT TB PPDU may be used for transmission of a response to a trigger frame.

Referring to fig. 4b, the EHT TB PPDU may include or consist of an EHT preamble (hereinafter, referred to as a PHY preamble or preamble), a data field, and a Packet Extension (PE) field. The EHT preamble may include or consist of a front EHT modulation field and an EHT modulation field. The front EHT modulation field may include or consist of a non-HT short training field (L-STF), a non-HT long training field (L-LTF), a non-HT signal (L-SIG) field, a repeated non-HT signal (RL-SIG) field, and a universal signal (U-SIG) field. The EHT modulation field may include or consist of an EHT short training field (EHT-STF) and an EHT long training field (EHT-LTF). In some embodiments, the L-STF may be followed by an L-LTF, followed by an L-SIG field, followed by an RL-SIG field, followed by a U-SIG field, followed by an EHT-STF, followed by an EHT-LTF, followed by a data field, followed by a PE field. In the EHT TB PPDU, there is no EHT-SIG field because the trigger frame transmits necessary information, and the duration of the eht_stf field in the EHT TB PPDU is twice the duration of the EHT-STF field in the EHT MU PPDU.

Since the description of each field in the EHT MU PPDU is applicable to the EHT TB PPDU, the description of the respective fields in the EHT TB PPDU will be omitted.

For EHT MU PPDUs and EHT TB PPDUs, the pre-EHT modulation field may be replicated over multiple 20MHz channels when the EHT modulation field occupies more than one 20MHz channel.

Hereinafter, an electronic device for facilitating wireless communication according to various embodiments will be described with reference to fig. 5.

Referring to fig. 5, an electronic device 30 for facilitating wireless communication according to an embodiment may include a processor 31, a memory 32, a transceiver 33, and an antenna unit 34. The transceiver 33 may include a transmitter 100 and a receiver 200.

The processor 31 may perform a Medium Access Control (MAC) function, a PHY function, an RF function, or a combination of some or all of the above. In some embodiments, the processor 31 may include some or all of the transmitter 100 and the receiver 200. The processor 31 may be coupled directly or indirectly to the memory 32. In some embodiments, the processor 31 may include one or more processors.

The memory 32 may be a non-transitory computer-readable recording medium storing instructions that, when executed by the processor 31, cause the electronic device 30 to perform the operations, methods, or processes described in this disclosure. In some embodiments, memory 32 may store instructions required by one or more of processor 31, transceiver 33, and other components of electronic device 30. The memory may further store an operating system and application programs. The memory 32 may include, be implemented as, or be included in read-write memory, read-only memory, volatile memory, non-volatile memory, or a combination of some or all of the foregoing.

The antenna unit 34 includes one or more physical antennas. When multiple-input multiple-output (MIMO) or multi-user MIMO (MU-MIMO) is used, the antenna unit 34 may include more than one physical antenna.

Fig. 6 shows a block diagram of a transmitter according to an embodiment.

Referring to fig. 7, 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.

The encoder 101 may encode input data to generate encoded data. For example, encoder 101 may be a Forward Error Correction (FEC) encoder. The FEC encoder may comprise or be implemented as a Binary Convolutional Code (BCC) encoder or a Low Density Parity Check (LDPC) encoder.

The interleaver 103 may interleave bits of the encoded data from the encoder 101 to change the order of the bits and output the interleaved data. In some embodiments, interleaving may be applied when BCC coding is employed.

The mapper 105 may map the interleaved data into constellation points to generate blocks of constellation points. If LDPC encoding is used in encoder 101, mapper 105 may further perform LDPC tone mapping instead of constellation mapping.

IFT 107 may convert the blocks of constellation points into time domain blocks corresponding to symbols using an Inverse Discrete Fourier Transform (IDFT) or an Inverse Fast Fourier Transform (IFFT).

GI inserter 109 may preset a GI for the symbol.

The RF transmitter 111 may convert the symbols into RF signals and transmit the RF signals via the antenna unit 34.

Fig. 7 shows a block diagram of a receiver according to an embodiment.

Referring to fig. 7, a receiver 200 according to an 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.

RF receiver 201 may receive RF signals through antenna element 34 and convert the RF signals to one or more symbols.

GI remover 203 may remove the GI from the symbol.

Depending on the implementation, FT 205 may convert symbols corresponding to the time domain block into a block of constellation points by using a Discrete Fourier Transform (DFT) or a Fast Fourier Transform (FFT).

The demapper 207 may demap the blocks of constellation points into demapped data bits. If LDPC encoding is used, the demapper 207 may further perform LDPC tone 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.

Decoder 211 may decode the deinterleaved data bits to generate decoded bits. For example, the decoder 211 may be an FEC decoder. The FEC decoder may comprise 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.

The Link Adaptation (LA) parameters of the WLAN system may be transmitted as part of the MAC header. These parameters may be carried in the HT control field in the MAC header. Hereinafter, the format of the MAC frame will be described with reference to fig. 10, 11, 12, and 13.

To reduce latency, unnecessary overhead traffic or transmissions may be removed. For example, the WLAN system may support one or more PPDU types without data fields and may carry critical information in the SIG field instead of the MAC frame.

The IEEE 802.11be Extremely High Throughput (EHT) task group is currently developing the next generation Wi-Fi standard to achieve higher data rates, lower latency, and more reliable connections, thereby enhancing the user experience. One of the main features of Wi-Fi 7 is multi-link operation (MLO). Since most current access points and stations contain dual band or tri-band capabilities, the newly developed MLO feature enables packet-level link aggregation in the MAC over multiple different physical layer links. By load balancing according to traffic requirements, MLOs can achieve significantly higher throughput and lower latency to enhance reliability in heavily loaded networks. With MLO capabilities, a multi-link device (MLD) includes multiple devices "attached" to an upper Logical Link Control (LLC) layer, allowing parallel data transmission and reception in multiple channels over a single or multiple frequency bands (e.g., including 2.4GHz, 5GHz, and 6 GHz).

Hereinafter, a multilink operation according to an embodiment will be described with reference to fig. 8 and 9.

As shown in fig. 8, an access point multilink device 300 may be associated with a non-access point multilink device 400 for MLO. The access point multilink device 300 and the non-access point multilink device 400 may be electronic devices 30.

The access point multilink device 300 may include a plurality of accessory access points 310 and a medium access control service access point 320. Each accessory access point 310 may include a physical layer interface for the wireless medium. Each accessory access point 310 may have its own medium access control address corresponding to a lower medium access control address. The medium access control address of each of the attached access points of the access point multilink device 300 may be different from the medium access control addresses of any other attached access points of the access point multilink device 300. The access point multilink device 300 may have a multilink device media access control address corresponding to an upper layer media access control address. The accessory access points 310 may share a single medium access control service access point 320 and communicate with higher layers (layer 3 or network layers) through the medium access control service access point 320. In some embodiments, the accessory access points 310 may share a single IP address.

The non-access point multilink device 400 may include a plurality of secondary stations 410 and a medium access control service access point 420. Each secondary station 410 may include a PHY interface for a wireless medium. Each secondary station 410 may have its own medium access control address corresponding to the lower medium access control address. The medium access control address of each secondary station of the non-access point multilink device 400 may be different from the medium access control address of any other secondary station 410 of the non-access point multilink device 400. The non-access point multi-link device 400 may have a multi-link device medium access control address corresponding to an upper layer medium access control address. The secondary stations 410 may share a single medium access control service access point 420 and communicate with higher layers (layer 3 or network layers) through the medium access control service access point 420. In some embodiments, the secondary stations 410 may share a single IP address.

In some embodiments, the plurality of secondary access points 310 are associated with a respective one of the plurality of links 40 and the plurality of secondary stations 410 are associated with a respective one of the plurality of links 40. The plurality of links 40 are associated with a respective one of a plurality of frequency bands (e.g., including one or more of 2.4GHz, 5GHz, 6GHz, and millimeter frequency bands). Millimeter-frequency range may refer to frequencies from 30 to 300 GHz. Radio waves in the millimeter frequency band have a wavelength from 10 to 1 millimeter. For convenience, in this disclosure, millimeter frequency bands may refer to frequency bands above 45 GHz.

In some embodiments, the access point multilink device 300 and the non-access point multilink device 400 may establish multiple links 40 between their affiliated access points 310 and stations 410. In some embodiments, there may be (but is not limited to) 4 links 40. In this example, an ith link 40 may be established between the ith secondary access point 310 and the ith secondary station 410, the link 40 being at N _i Operating in the GHz band, where N ₁ ＝2.4，N ₂ ＝5，N ₃ =6, and N ₄ =45 (i=1 …). Each link 40 may independently enable channel access and frame exchange between the access point multilink device 300 and the non-access point multilink device 400, which may improve data throughput and reduce latency.

Wi-Fi devices can connect to a single link and switch links between 2.4GHz, 5GHz, and 6GHz bands. However, when Wi-Fi devices switch their links, a switching overhead or delay of up to 100ms may occur. Thus, MLO may be highly desirable for real-time applications such as video calls, wireless VR headphones, cloud games, and other delay-sensitive applications, because MLD may maintain two or more links. As shown in fig. 9, the access point multilink device 300 includes a first access point 310a and a second access point 310b, and the non-access point multilink device 400 includes a first station 410a and a second station 410b. A first link 40a is established between the first access point 310a and the first station 410 a. A second link 40a is established between the second access point 310b and the second station 410b.

Different channel access methods are defined in the IEEE 802.11be specification draft according to both asynchronous and synchronous transmission modes. In the asynchronous transfer mode, the MLD can asynchronously transfer frames over multiple links without aligning the start times of the frames, as shown in fig. 9. In synchronous transmission mode, the start times are aligned on the various links. In either mode, each link may have its own primary channel and parameters, including a Packet Protocol Data Unit (PPDU), a Modulation and Coding Scheme (MCS), enhanced Distributed Channel Access (EDCA), and so on.

As described above, a multi-link device (MLD) supporting multi-link operation (MLO) is defined in the wireless local area network. When the multi-link device performs multi-link operation, the multi-link device may establish multiple links, and each link may use a different frequency band. For example, frequency bands that may be used in the multilink operation may include one or more of 2.4GHz, 5GHz, and 6 GHz. With the development of Wi-Fi technology, use cases are being considered, which must meet various advanced requirements. For example, one of the approaches to meeting these needs is to extend to a wider spectrum. In order to achieve a wider spectrum, frequency bands above 45GHz, for example, but not limited to, can be additionally employed in addition to the existing 2.4GHz, 5GHz, and 6GHz frequency bands, which are referred to as millimeter wave bands (mm bands).

As shown in fig. 10, an access point multilink device 300 may be associated with a non-access point multilink device 400 for MLO. The access point multilink device 300 and the non-access point multilink device 400 may be electronic devices 30.

The access point multilink device 300 may include, for example, but is not limited to, two access points: a first access point 310a and a second access point 310b. Non-access point multilink device 400 may include, for example (but not limited to, two stations: a first station 410a and a second station 410b.

The first link 40a and the second link 40b may be established between the access point multilink device 300 and the non-access point multilink device 400. The first access point 310a attached to the access point multilink device 300 and the first station 410a attached to the non-access point multilink device 400 may be connected by using the first link 40a in the frequency band above 45GHz, and the second access point 310b attached to the access point multilink device 300 and the second station 410b attached to the non-access point multilink device 400 may be connected by using the second link 40b in the frequency band below 7 GHz.

Based on the characteristics of the millimeter wave band, path loss in millimeter waves is one of the important factors compared to the band below 7GHz because the millimeter wave wavelength is too short. Thus, beamforming training may be performed between the transmitter and the receiver for wireless communication over the millimeter-wave band. In some embodiments, each of the transmitter and receiver may be an access point or a non-access point station.

Hereinafter, a beamforming training process will be described with reference to fig. 11 and 12.

As shown in fig. 11, the first access point 310a creates n beams and transmits signals over these beams. The first station 410a receives signals through these beams. In some embodiments, each of the first access point 310a and the first station 410a may be an access point or a non-access point station.

When the first access point 310a wants to perform TX beamforming training to transmit data to the first station 410a, the first access point 310a may initiate a channel sounding procedure. In operation 1201, the first access point 310a creates beams in multiple directions indicated by indexes of 1 to n.

In operation 1203, the first access point 310a may sequentially transmit training signals over n beams. In some embodiments, the training signal may be a null data packet.

In operation 1205, the first station 410a may receive signals transmitted by the first access point 310a over the beams and measure the strength of the received power of each beam. In some embodiments, the first station 410a may determine which of the measured beams has the highest intensity.

In operation 1207, the first station 410a may generate beamforming feedback report information. In operation 1209, the first station 410a may transmit a beamforming feedback report frame including beamforming feedback report information regarding a beam to the first access point 310 a.

In operation 1211, the first access point 310a may transmit a data frame to the first station 410a over one of the beams in the millimeter wave band based on the information about the beam reported by the first station 410 a. In some embodiments, the first station 410a may select one of the n beams having the highest intensity and transmit the data frame through the selected beam.

Throughput may be greatly improved when beamforming in the millimeter-wave band is employed for wireless communication, but the time required to complete the beamforming training procedure may result in delays and delays.

Hereinafter, an effective method for improving a beamforming training procedure in the millimeter wave band will be described.

As shown in fig. 13, when at least one of the access point multilink device 300 and the non-access point multilink device 400 has data to be transmitted between the access point multilink device 300 and the non-access point multilink device 400 and the link 40b has been enabled, data can be transmitted between the access point multilink device 300 and the non-access point multilink device 400 by using the link 40b of the lower than 7GHz band without waiting for completion of the beamforming training procedure for the link 40a using the millimeter band. Meanwhile, even when the link 40b has been enabled, the beamforming training procedure may be performed in a frequency band above 45 GHz. Once the beamforming training procedure is completed in the millimeter wave band, data transmission and reception may continue over link 40a and link 40b using the millimeter wave band. Accordingly, a data transmission delay or delay due to a time required for a beamforming training procedure can be reduced.

In some embodiments, each of the first access point 310a, the second access point 310b, the first station 410a, and the second station 410b may be an access point or a non-access point station.

When at least one of the access point multilink device 300 and the non-access point multilink device 400 has data to be transmitted between the access point multilink device 300 and the non-access point multilink device 400 and the link 40b has been enabled, the access point multilink device 300 may request the second access point 310b to transmit a data frame comprising the received data to the non-access point multilink device 400 through the link 40 b. In operation 1401, the second access point 310b may transmit a data frame including the received data to the second station 410b by employing the link 40b of the lower than 7GHz band. In some embodiments, during operation 1401, the second station 410b may send a received data frame or an acknowledgement frame of a certain data frame to the second access point 310b by employing the link 40b below the 7GHz band.

Meanwhile, the access point multilink device 300 may request the first access point 310a to perform a beamforming training procedure with the first station 410 a. In operation 1403, the first access point 310a may perform a beamforming training procedure with the first station 410a even when the link 40b has been enabled, while the second access point 310b transmits data to the second station 410 b. In some embodiments, the beamforming training procedure may follow the procedure shown in fig. 12.

After performing the beamforming training procedure, the access point multilink device 300 may request the first access point 310a to transmit a data frame comprising the received data to the non-access point multilink device 400 over link 40 a. In operation 1405, the first access point 310a may transmit a data frame including the received data to the first station 410a over the link 40a employing the frequency band above 45 GHz.

If at least one of the access point multilink device 300 and the non-access point multilink device 400 has data to be transmitted between the access point multilink device 300 and the non-access point multilink device 400, the access point multilink device 300 may request the second access point 310b to transmit a data frame comprising the received data to the non-access point multilink device 400 over the link 40 b. In operation 1501, the second access point 310b may transmit a data frame including the received data to the second station 410b by employing the link 40b of the lower than 7GHz band. In some embodiments, during operation 1501, the second station 410b may send the received data frame or an acknowledgement frame of a certain data frame to the second access point 310b by employing the link 40b below the 7GHz band.

Meanwhile, the access point multilink device 300 may request the first access point 310a to perform a beamforming training procedure with the first station 410 a. In operation 1503, if the first access point 310a intends to perform beamforming training in the millimeter-wave band, the first access point 310a may transmit a beamforming training request including beamforming training information to the second access point 310 b. In some embodiments, the beamforming training information may include a start time of a beamforming training procedure between the first access point 310a and the first station 410 a.

In operation 1505, the second access point 310b may transmit a beamforming training request frame including beamforming training information to the second station 410b over a link below 7 GHz.

In operation 1507, the second station 410b may transmit a beamforming training request including beamforming training information to the first station 410 a.

In operation 1515, when the received beamforming training information includes a start time of the beamforming training procedure, the first station 410a may wake up at the start time.

In operation 1517, when the received beamforming training information includes a start time of the beamforming training procedure, the first access point 310a may start the beamforming training procedure with the first station 410a at the start time. In some embodiments, the first access point 310a may perform a beamforming training procedure with the first station 410a, while the second access point 310b transmits data to the second station 410 b. In some embodiments, the beamforming training procedure may follow the procedure shown in fig. 12.

After performing the beamforming training procedure, the access point multilink device 300 may request the first access point 310a to transmit a data frame comprising the received data to the non-access point multilink device 400 over link 40 a. In operation 1519, the first access point 310a may transmit a data frame including the received data to the first station 410a through the link 40a employing the frequency band of 45GHz or more.

Hereinafter, a rapid beamforming training procedure in the millimeter wave band will be described.

As shown in fig. 16, a beamforming training procedure may be performed between the first access point 310a and the first station 410a for the link 40a employing a frequency band above 45GHz, even when the link 40b has been enabled. After the first station 410a receives the signal transmitted by the first access point 310a through the beam, measures the intensity of the received power of each beam, and generates beamforming feedback report information, the first station 410a may transmit the beamforming feedback report information to the second station 410b such that the second station 410b transmits the beamforming feedback report information to the access point multilink device by employing the link 40b lower than the 7GHz band.

If at least one of the access point multilink device 300 and the non-access point multilink device 400 has data to be transmitted between the access point multilink device 300 and the non-access point multilink device 400, the access point multilink device 300 may request the second access point 310b to transmit a data frame comprising the received data to the non-access point multilink device 400 over the link 40 b. In operation 1701, the second access point 310b may transmit a data frame including data to the second station 410b by employing the link 40b of the lower than 7GHz band. In some embodiments, during operation 1701, the second station 410b may send an acknowledgement frame of the received data frame or some data frame to the second access point 310b by employing a link 40b below the 7GHz band.

Meanwhile, the access point multilink device 300 may request the first access point 310a to perform a beamforming training procedure with the first station 410 a. When the first access point 310a wants to perform TX beamforming training to transmit data to the first station 410a, the first access point 310a may initiate a channel sounding procedure. In operation 1703, the first access point 310a may create beams in a plurality of directions indicated by indexes of 1 to n, and may sequentially transmit training signals through n beams. In some embodiments, the training signal may be a beamforming training frame. In some embodiments, the beamforming training frame may include information indicating over which beam the beamforming training frame was transmitted, and the information may be an index of the beam. In some embodiments, the beamforming training frame may use or include the medium access control address of the first station 410a as the receiver address value. In some embodiments, the beamforming training frame may use or include a broadcast address as a receiver address value to enable a plurality of non-access point stations including other non-access point stations and the first station 410a to measure the strength of the beam and report measurement information to the first access point 310 a.

In operation 1705, the first station 410a may sequentially receive signals transmitted by the first access point 310a through the beams, and may measure the intensity of the received power of each beam. In some embodiments, the first station 410a may determine which of the measured beams has the highest intensity. In some embodiments, when the beamforming training frame may use or include the medium access control address of the first station 410a as the receiver address value, only the first station 410a may measure the strength of the received power of each beam. In some embodiments, when the beamforming training frame may use or include a broadcast address as a receiver address value, a plurality of stations including the first station 410a may sequentially receive signals transmitted by the first access point 310a through the beam and may measure the intensity of the received power of each beam.

In operation 1707, the first station 410a may generate beamforming feedback report information. In some embodiments, when the beamforming training frame may use or include the medium access control address of the first station 410a as the receiver address value, only the first station 410a may generate the beamforming feedback report information. In some embodiments, when the beamforming training frame may use or include a broadcast address as the receiver address value, a plurality of stations including the first station 410a may generate beamforming feedback report information.

In operation 1709, the first station 410a may transmit beamforming feedback report information regarding the beam to the second station 410 b. In some embodiments, the beamforming feedback report information may include at least one of an index of a beam having the strongest received power, an order of received power strengths of each beam index, or a P & Q matrix measured by the first station 410 a.

In operation 1711, the second station 410b may transmit a beamforming feedback report frame including beamforming feedback report information regarding the beam to the second access point 310b by employing the link 40b of the lower 7GHz band.

In operation 1713, the second access point 310b may send beamforming feedback report information regarding the beam to the first access point 310 a. In some embodiments, when the beamforming training frame may use or include the medium access control address of the first station 410a as the receiver address value, the first access point 310a may receive beamforming feedback report information from the first station 410a instead of from other stations than the first station 410 a. In some embodiments, the first access point 310a may receive beamforming feedback report information from a plurality of stations including the first station 410a when the beamforming training frame may use or include a broadcast address as a receiver address value.

In operation 1715, the first access point 310a may send a data frame to the first station 410a over one of the beams in the millimeter wave band based on the information about the beams reported by the first station 410 a. In some embodiments, the first station 410a may select one of the n beams having the highest intensity and transmit the data frame through the selected beam.

According to the embodiment shown in fig. 17, beamforming training can be performed whenever there is no data to be transmitted. After completion of the beamforming training, the data may be transmitted over the known best beam, which is reported by using link 40b below the 7GHz band.

As described above, beamforming training may be performed for links that employ millimeter wave bands. However, beamforming training may be performed on one or more links that employ other frequency bands than the millimeter wave band.

The various illustrative blocks, units, modules, components, methods, operations, instructions, items, and algorithms may be implemented or performed by processing circuitry.

Reference to an element in the singular is not intended to mean one and only one but rather one or more unless specifically stated. For example, "a" module may refer to one or more modules. Elements beginning with "a," "an," "the," or "said" do not exclude the presence of other identical elements, if not further limited.

Titles and subtitles, if any, are merely convenient for use and do not limit the subject technology. The term "exemplary" is used to mean serving as an example or illustration. To the extent that the terms "includes," "having," "carries," "contains," and the like are used, such terms are intended to be inclusive in a manner similar to the term "comprising" as "comprising" is interpreted when employed as a transitional word in a claim. Relational terms such as first and second may be used to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

Phrases such as one aspect, the aspect, another aspect, some aspects, one or more aspects, an embodiment, the embodiment, another embodiment, some embodiments, one or more implementations, an example, the example, another example, some examples, one or more examples, a configuration, the configuration, another configuration, some configurations, one or more configurations, subject technology, the disclosure, the present disclosure, and other variations thereof, are all for convenience and do not denote that disclosure relating to such phrases is essential to the subject technology, or that such disclosure applies to all configurations of the subject technology. The disclosure relating to such phrases may apply to all configurations or one or more configurations. The disclosure relating to such phrases may provide one or more examples. A phrase such as an aspect or aspects may refer to one or more aspects and vice versa, and the same applies to the other phrases previously described.

The phrase "at least one" preceding a series of items, along with the term "and" or "separating any items, modifies the list as a whole rather than the individual components of the list. The phrase "at least one" does not require the selection of at least one item; conversely, a phrase allows the following meanings: including at least one of any of the items, and/or at least one of any combination of the items, and/or at least one of each of the items. 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 alone, B alone, or C alone; A. any combination of B and C; and/or at least one of each of A, B and C.

It is to be understood that the specific order or hierarchy of steps, operations, or flows disclosed is an illustration of exemplary approaches. Unless explicitly stated otherwise, it is to be understood that the particular order or hierarchy of steps, operations or flows may be performed in a different order. Some steps, operations, or flows may be performed concurrently or as part of one or more other steps, operations, or flows. The accompanying method claims present elements of the various steps, operations, or flows in a sample order, if any, and are not meant to be limited to the specific order or hierarchy presented. These may be performed serially, linearly, in parallel or in a different order. It should be understood that the described instructions, operations, and systems may generally be integrated together in a single software/hardware product or packaged into multiple software/hardware products.

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

All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Furthermore, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element should be construed as a admission that the element is entitled to antedate 35u.s.c. ≡112 by paragraph 6 unless the element is expressed or explicitly stated or, in the case of method claims, the element is expressed by the phrase for the steps of … ….

The title, background, brief description of the drawings, abstract and drawings are contained herein in the present disclosure and are provided as illustrative examples of the present disclosure and not as limiting descriptions. It is submitted with the understanding that they will not be used to limit the scope or meaning of the claims. Furthermore, in the detailed description, it can be seen that the specification provides an illustrative example, and various features are grouped together in various embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed subject matter requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed configuration or operation. The following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separately claimed subject matter.

The claims are not intended to be limited to the aspects described herein but are to be accorded the full scope consistent with the language claims and encompassing all legal equivalents. Nevertheless, no claim should be construed as an admission that any of the claims fall within the scope of the applicable patent statutes.

Claims

1. An access point multilink device associated with a non-access point multilink device comprising a first station and a second station, the access point multilink device comprising:

a first access point affiliated with the access point multilink device and associated with the first station; and

a second access point affiliated with the access point multilink device and associated with the second station,

wherein the first access point establishes a first link with the first station,

the second access point establishes a second link with the second station,

the first link uses a millimeter wave band,

the second link uses a frequency band below the millimeter wave band, an

When the second link is enabled, the first access point transmits a beamforming training signal for the first link to the first station and receives beamforming feedback information from the first station.

2. The access point multilink device of claim 1, wherein the second access point transmits a beamforming training request for the first link to the second station via the second link.

3. The access point multilink device of claim 2, wherein the beamforming training request comprises beamforming training information for the first link.

4. The access point multilink device of claim 3, wherein the beamforming training information comprises a start time of a beamforming training procedure for the first link.

5. The access point multilink device of claim 4, wherein the first access point begins the beamforming training procedure at the start time.

6. The access point multilink device of claim 5, wherein the second station transmits the beamforming training information to the first station and the first station wakes up at the start time.

7. The access point multilink device of claim 1, wherein the first access point receives the beamforming feedback information from the second access point, the second access point receives the beamforming feedback information from the second station via the second link.

8. The access point multilink device of claim 7, wherein the beamforming training signal comprises a medium access control address of the first station.

9. The access point multilink device of claim 7, wherein the beamforming training signal comprises a broadcast address.

10. The access point multilink device of claim 1, wherein the first access point transmits a beamforming training signal for the first link to the first station while the second access point exchanges data frames with the second station.

11. A non-access point multilink device associated with an access point multilink device comprising a first access point and a second access point, the non-access point multilink device comprising:

a first station affiliated with the non-access point multilink device and associated with the first access point; and

a second station affiliated with the non-access point multilink device and associated with the second access point,

wherein the first station establishes a first link with the first access point,

the second station establishes a second link with the second access point,

the first link uses a millimeter wave band,

the second link uses a frequency band below the millimeter wave band, an

When the second link is enabled, the first station receives a beamforming training signal for the first link from the first access point and transmits beamforming feedback information to the first access point.

12. The non-access point multilink device of claim 11, wherein the second station receives a beamforming training request for the first link from the second access point via the second link.

13. The non-access point multilink device of claim 12, wherein the beamforming training request comprises beamforming training information for the first link.

14. The non-access point multilink device of claim 13, wherein the beamforming training information comprises a start time of a beamforming training procedure for the first link.

15. The non-access point multilink device of claim 14, wherein the first station begins the beamforming training procedure at the start time.

16. The non-access point multilink device of claim 15, wherein the second station transmits the beamforming training information to the first station and the first station wakes up at the start time.

17. The non-access point multilink device of claim 11, wherein the first station transmits the beamforming feedback information to the second station, the second station transmitting the beamforming feedback information to the second access point via the second link.

18. The non-access point multilink device of claim 17, wherein the beamforming training signal comprises a medium access control address of the first station.

19. The non-access point multilink device of claim 17, wherein the beamforming training signal comprises a broadcast address.

20. The non-access point multilink device of claim 11, wherein the first station receives a beamforming training signal for a first link from the first access point while the second station exchanges data frames with the second access point.