Wireless communication device for facilitating wireless communication

Abstract

A wireless communication device for facilitating wireless communication is provided. In the wireless communication device, an access point transmits a measurement announcement frame addressed to one or more neighboring access points and stations. The measurement announcement frame triggers the one or more neighboring access points to send training frames to the station and triggers the station to measure channel information based on the training frames from the one or more neighboring access points. The access point receives a measurement report frame from the station, the measurement report frame including channel information. The access point determines a relay access point based on a measurement report frame and sends a first data unit to the station via the relay access point.

Description

Technical Field

[0001] The present disclosure relates to wireless communication systems, and more particularly to, for example but not limited to, efficient relay operations and roaming operations. Background Art

[0002] If the channel state between an access point (AP) station (STA) and a non-AP STA in a wireless network is not good, the AP STA may not use a high modulation and coding scheme (MCS) index to send data to the non-AP STA. In this scenario, relay transmission can be used. In order to perform relay transmission, one or more nodes need to be selected in the neighboring APs. The selected one or more neighboring APs can act as relay nodes between the AP STA and the non-AP STA. Therefore, it is necessary to introduce frame and channel measurements that support the effective selection of one or more appropriate relay nodes and effective relay transmission.

[0003] The descriptions set forth in the Background section should not be assumed to be prior art merely because they are set forth in the Background section. The Background section may describe aspects or embodiments of the present disclosure. Summary of the invention

[0004] Some embodiments may enable an AP STA to select one or more appropriate relay nodes among neighboring AP STAs for efficient relay transmission. Some embodiments may enable an AP STA to perform efficient relay transmission using one or more selected relay nodes. Some embodiments may enable a non-AP STA to efficiently change its associated AP STA after relay transmission.

[0005] In some embodiments, a wireless communication device for facilitating wireless communication includes a processing circuit configured to facilitate: sending a measurement notification frame addressed to one or more neighboring access points and a station, wherein the measurement notification frame triggers one or more neighboring access points to send a training frame to the station and triggers the station to measure channel information based on the training frame from the one or more neighboring access points; receiving a measurement report frame from the station, the measurement report frame including channel information; determining a relay access point based on the measurement report frame; and sending a first data unit to the station via the relay access point.

[0006] In some embodiments, sending the first data unit to the station via the relay access point includes sending the first data unit to the relay access point to trigger the relay access point to generate a second data unit based on the first data unit and send the second data unit to the station.

[0007] In some embodiments, the processing circuit is further configured to facilitate receiving an acknowledgement frame from the station indicating that the station has successfully received the second data unit via the relay access point.

[0008] In some embodiments, the acknowledgement frame is modulated and coded based on a lowest modulation and coding scheme (MCS) index.

[0009] In some embodiments, the second data unit includes an acknowledgment frame, and the acknowledgment frame is used to notify the wireless communication device that the relay access point successfully received the first data unit.

[0010] In some embodiments, the measurement announcement frame includes information indicating one or more neighboring access points that sent the training frame and information indicating a station that sent the measurement report frame in response to the measurement announcement frame.

[0011] In some embodiments, the measurement announcement frame includes information indicating when the one or more neighboring access points transmit the training frame and information indicating when the station transmits the measurement report frame.

[0012] In some embodiments, the measurement announcement frame includes information requesting the station to include in the measurement report frame information indicating whether the station prefers to change an access point associated with the station after a relay operation.

[0013] In some embodiments, the measurement report frame has information indicating that the station wants to change an access point associated with the station after relay operation.

[0014] In some embodiments, the first data unit includes information for instructing the station to change an access point associated with the station after the station transmits an acknowledgment frame to the first data unit.

[0015] In some embodiments, a wireless communication device for facilitating wireless communication includes a processing circuit configured to facilitate: receiving a measurement notification frame addressed to one or more neighboring access points and a station from an associated access point, wherein the associated access point addresses a first data unit to the wireless communication device, the measurement notification frame triggers the one or more neighboring access points to send a training frame to the station, and triggers the station to measure channel information based on the training frame from the one or more neighboring access points; sending a measurement report frame to the associated access point, the measurement report frame including channel information; and receiving a second data unit from a relay access point determined based on the measurement report frame, the second data unit being generated by the relay access point based on the first data unit.

[0016] In some embodiments, the processing circuit is further configured to cause: sending an acknowledgement frame to the associated access point indicating that the station has successfully received the second data unit via the relay access point.

[0017] In some embodiments, the acknowledgement frame is modulated and coded based on a lowest modulation and coding scheme (MCS) index.

[0018] In some embodiments, the second data unit includes an acknowledgment frame, and the acknowledgment frame is used to notify the associated access point that the relay access point successfully received the first data unit.

[0019] In some embodiments, the measurement announcement frame includes information indicating one or more neighboring access points that transmit training frames and information indicating a station that transmits the measurement report frame in response to the measurement announcement frame.

[0020] In some embodiments, the measurement announcement frame includes information indicating when the one or more neighboring access points transmit training frames and information indicating when the station transmits the measurement report frame.

[0021] In some embodiments, the measurement announcement frame includes information indicating that the station is requested to include in the measurement report frame information indicating whether the station prefers to change an access point associated with the station after a relay operation.

[0022] In some embodiments, the measurement report frame has information indicating that the station wants to change an access point associated with the station after relay operation.

[0023] In some embodiments, the first data unit includes information for instructing the station to change an access point associated with the station after the station sends an acknowledgment frame to the first data unit.

[0024] In some embodiments, the training frame is a null data physical layer (PHY) protocol data unit (PPDU). BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of an example wireless communication network is shown.

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

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

[0028] Figure 4AAn EHT MU PPDU format according to an embodiment is shown.

[0029] Figure 4B An EHT TB PPDU format according to an embodiment is shown.

[0030] Figure 5 is a block diagram of an electronic device for facilitating wireless communications according to an embodiment.

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

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

[0033] Figure 8 A multi-link operation (MLO) in synchronous transfer mode according to an embodiment is shown.

[0034] Fig. 9 An exemplary topology for a relay operation scenario according to an embodiment is shown.

[0035] Fig.10 Channel measurement between a STA and a neighboring AP according to an embodiment is shown.

[0036] Fig.11 An exemplary topology for a relay operation scenario according to an embodiment is shown.

[0037] Fig.12 An exemplary data transmission through a relay AP according to an embodiment is shown.

[0038] Fig.13 Channel measurement between a STA and a neighboring AP according to an embodiment is shown.

[0039] Fig.14 An exemplary data transmission through a relay AP according to an embodiment is shown.

[0040] Fig.15 An exemplary topology change after roaming based on relay operation according to an embodiment is shown. DETAILED DESCRIPTION

[0041] The detailed description set forth below is intended to describe various embodiments and is not intended to represent a unique embodiment. As will be appreciated by those skilled in the art, the described embodiments may be modified in a variety of different ways, all without departing from the scope of the present disclosure. Therefore, the drawings and descriptions should be considered to be illustrative and non-restrictive in nature. The same reference numerals represent the same elements.

[0042] The following detailed description is described with reference to a wireless LAN system according to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless standard (including current and future modifications). 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.

[0043] In some embodiments, an apparatus or device such as an AP STA and a non-AP 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 that stores instructions that can be executed by a hardware processor installed in the apparatus; and at least one processor that is configured to perform the 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.

[0044] Figure 1 A schematic diagram of an example wireless communication network is shown.

[0045] refer to Figure 1 , a basic service set (BSS) 10 may include a plurality of stations (STAs), including an access point (AP) station (APSTA) 11 and one or more non-AP stations (non-AP STAs) 12. For convenience, non-AP STAs may be interchangeably referred to as users or STAs. STAs 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, AP STAs and non-AP STAs may be referred to as APs and STAs, respectively. In some embodiments, AP STAs and non-AP STAs may be collectively referred to as stations (STAs).

[0046] Multiple STAs may participate in multi-user (MU) transmission. In MU transmission, an AP STA 11 may simultaneously send downlink (DL) frames to multiple non-AP STAs 12 in the BSS 10 based on different resources, and multiple non-AP STAs 12 may simultaneously send uplink (UL) frames to an AP STA 11 in the BSS 10 based on different resources.

[0047] For MU transmission, multi-user multiple input multiple output (MU-MIMO) transmission or orthogonal frequency division multiple access (OFDMA) transmission may be used. In MU-MIMO transmission, using one or more antennas, multiple non-AP STAs 12 may simultaneously send independent data streams to the AP STA 11 on the same subcarrier or simultaneously receive independent data streams from the AP STA 11. Different frequency resources may be used as different resources in MU-MIMO transmission. In OFDMA transmission, multiple non-AP STAs 12 may simultaneously send independent data streams to the AP STA 11 on different subcarrier groups or simultaneously receive independent data streams from the AP STA 11. Different spatial streams may be used as different resources in MU-MIMO transmission.

[0048] Figure 2 An example of a timing diagram illustrating inter-frame space (IFS) relationships between stations according to an embodiment.

[0049] Specifically, Figure 2 A CSMA (Carrier Sense Multiple Access) / CA (Collision Avoidance) based frame transmission process for avoiding collision between frames in a channel is shown.

[0050] Data frames, control frames, or management frames may be exchanged between STAs.

[0051] Data frames can be used for data transmission forwarded to higher layers. Figure 2 , delaying access when the medium is busy until a type of IFS duration has passed. If the distributed coordination function IFS (DIFS) has passed from the time when the medium has been idle, the STA can send a data frame after performing a backoff.

[0052] Management frames may be used to exchange management information that is not forwarded to a higher layer. Subtype frames of management frames may include beacon frames, association request / response frames, probe request / response frames, and authentication request / response frames.

[0053] The control frame may be used to control access to the medium. Subtype frames of the control frame include a request to send (RTS) frame, a clear to send (CTS) frame, and an acknowledgement (ACK) frame. In the case where the control frame is not a response frame of another frame, if the DIFS has passed, the STA may send the control frame after performing a backoff. If the control frame is a response frame of the previous frame, the WLAN device may transmit the control frame without performing a backoff when the short IFS (SIFS) has passed. The type and subtype of the frame may be identified by the type field and the subtype field in the frame control field.

[0054] On the other hand, if the arbitration IFS (AIFS) of the access category (AC) (i.e., AIFS [AC]) has passed, the quality of service (QoS) STA may send a frame after performing a backoff. In this case, a data frame, a management frame, or a control frame that is not a response frame may use AIFC [AC].

[0055] In some embodiments, a point coordination function (PCF) enabled AP STA may send a frame after performing a backoff if the PCF IFS (PIFS) has elapsed. The PIFS duration may be less than DIFS but greater than SIFS.

[0056] Figure 3 OFDM symbols and OFDMA symbols according to an embodiment are shown.

[0057] 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 in future modifications of 802.11, such as EHT (extreme high throughput). One or more STAs may be allowed to use one or more resource units (RUs) in the entire operating bandwidth to send data simultaneously. As the minimum granularity, one RU may include a set of a predetermined number of subcarriers and be located at a predetermined position in an orthogonal frequency division multiplexing (OFDM) modulation symbol. Here, a non-AP STA may be associated or unassociated with an AP STA when responding simultaneously in the allocated RU within a specific time period, such as a short interframe space (SIFS). SIFS may refer to the duration 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 subsequent frame.

[0058] OFDMA is a multiple access scheme based on OFDM in which different subsets of subcarriers can be assigned to different users, allowing data transmission to or from one or more users simultaneously with high accuracy synchronization for frequency orthogonality. In OFDMA, users can be assigned different subsets of subcarriers, which can change from one physical layer (PHY) protocol data unit (PPDU) to the next. In OFDMA, an OFDM symbol is composed of subcarriers, and the number of subcarriers is a function of the PPDU bandwidth. Figure 3 The difference between OFDM and OFDMA is shown in FIG.

[0059] In the case of UL MU transmission, given that different STAs have their own capabilities and characteristics, the AP STA may want to have more control mechanisms over the medium by using more scheduled access, which may allow more frequent use of OFDMA / MU-MIMO transmission. The PPDU in UL MU transmission (MU-MIMO or OFDMA) may be sent as a response to a trigger frame sent by the AP. The trigger frame may have STA information and allocate RUs and multiple RUs (MRUs) to the STA. The STA information in the trigger frame may include a STA identifier (ID), MCS (modulation and coding scheme), and frame length. The trigger frame allows the STA to transmit a trigger-based (TB) PPDU (e.g., HE TB PPDU or EHT TB PPDU) segmented into RUs, and all RUs in response to the trigger frame are allocated to the requested non-AP STA accordingly. Thereafter, a single RU and multiple RUs may be referred to as RUs. Multiple RUs may include or consist of two, three or more predefined RUs.

[0060] In the EHT modification, two EHT PPDU formats are defined: EHT MU PPDU and EHT TB PPDU. Figure 4A and Figure 4B Describes the EHT MU PPDU and EHT TB PPDU.

[0061] Figure 4A An EHT MU PPDU format according to an embodiment is shown.

[0062] 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.

[0063] refer to Figure 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 pre-EHT modulation field and an EHT modulation field. The pre-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 the L-LTF, followed by the L-SIG field, followed by the RL-SIG field, followed by the U-SIG field, followed by the EHT-SIG field, followed by the EHT-STF, followed by the EHT-LTF, followed by the data field, and followed by the PE field.

[0064] The L-STF field may be used for packet detection, automatic gain control (AGC), and coarse frequency offset correction.

[0065] The L-LTF field can be used for channel estimation, fine frequency offset correction, and symbol timing.

[0066] The L-SIG field may be used to convey rate and length information.

[0067] The RL-SIG field may be a repetition of the L-SIG field and may be used to distinguish an EHT PPDU from a non-HT PPDU, a HT PPDU, and a VHT PPDU.

[0068] The U-SIG field may carry information necessary to interpret the EHT PPDU.

[0069] The EHT-SIG field may provide additional signaling to the U-SIG field for the STA to interpret the EHT MU PPDU. Hereinafter, the U-SIG field, the EHT-SIG field, or both may be referred to as the SIG field.

[0070] 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 resource unit allocations, such as RU allocations to be used in the EHT modulation field of the PPDU, RUs allocated for MU-MIMO, and the number of users in the MU-MIMO allocation. The user-specific field may include one or more user fields.

[0071] The user field for 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 field for MU-MIMO allocation may include a STA-ID subfield, an MCS subfield, a coding subfield, and a spatial configuration subfield.

[0072] The EHT-STF field may be used to improve automatic gain control estimation in MIMO transmissions.

[0073] The EHT-LTF field may enable the receiver to estimate the MIMO channel between the constellation mapper output set and the receive chain.

[0074] The data field may carry one or more physical layer convergence procedure (PLCP) service data units (PSDUs).

[0075] The PE field may provide additional receive processing time at the end of the EHT MU PPDU.

[0076] Figure 4B An EHT TB PPDU format according to an embodiment is shown.

[0077] The EHT TB PUD may be used to transmit a response to a trigger frame.

[0078] refer to Figure 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 pre-EHT modulation field and an EHT modulation field. The pre-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 the L-LTF, followed by the L-SIG field, followed by the RL-SIG field, followed by the U-SIG field, followed by the EHT-STF, followed by the EHT-LTF, followed by the data field, and followed by the PE field. In the EHT TB PPUD, there is no EHT-SIG field because the trigger frame conveys necessary information, and the duration of the EHT_STF field in the EHT TB PPUD is twice the duration of the EHT-STF field in the EHT MU PPDU.

[0079] A description of each field in the EHT TB PPDU will be omitted because the description of each field in the EHT MU PPDU is applicable to the EHT TB PPDU.

[0080] For EHT MU PPDU and EHT TB PPUD, when the EHT modulation field occupies more than one 20 MHz channel, the pre-EHT modulation field may be replicated on multiple 20 MHz channels.

[0081] In the following, reference will be made to Figure 5 Electronic devices for facilitating wireless communications are described in accordance with various embodiments.

[0082] Figure 5 is a block diagram of an electronic device for facilitating wireless communications according to an embodiment.

[0083] refer to Figure 5 , the 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.

[0084] 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 foregoing. In some embodiments, the processor 31 may include some or all of the transmitter 100 and the receiver 200. The processor 31 may be directly or indirectly coupled to the memory 32. In some embodiments, the processor 31 may include one or more processors.

[0085] 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 programs described in the present disclosure. In some embodiments, the memory 32 may store instructions required by the processor 31, the transceiver 33, and one or more of the other components of the electronic device 30. The memory may also store operating systems and applications. The memory 32 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.

[0086] Antenna unit 34 includes one or more physical antennas. When multiple-input multiple-output (MIMO) or multi-user MIMO (MU-MIMO) is used, antenna unit 34 may include more than one physical antenna.

[0087] Figure 6 A block diagram of a transmitter according to an embodiment is shown.

[0088] Reference Figure 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.

[0089] The encoder 101 may encode input data to generate encoded data. For example, the encoder 101 may be a forward error correction (FEC) encoder. The FEC encoder may include or be implemented as a binary convolutional code (BCC) encoder or a low-density parity check (LDPC) encoder.

[0090] 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, when BCC encoding is adopted, interleaving may be applied.

[0091] The mapper 105 may map the interleaved data into constellation points to generate blocks of constellation points. If LDPC encoding is used in the encoder 101, the mapper 105 may further perform LDPC tone mapping instead of constellation mapping.

[0092] The IFT 107 may convert the block of constellation points into a time domain block corresponding to a symbol by using an Inverse Discrete Fourier Transform (IDFT) or an Inverse Fast Fourier Transform (IFFT).

[0093] The GI inserter 109 may prepend a GI to a symbol.

[0094] The RF transmitter 111 may convert the symbols into RF signals and transmit the RF signals via the antenna unit 34 .

[0095] Figure 7 A block diagram of a receiver according to an embodiment is shown.

[0096] Reference Figure 7 , the 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.

[0097] The RF receiver 201 may receive an RF signal via the antenna unit 34 and convert the RF signal into one or more symbols.

[0098] The GI remover 203 may remove GI from the symbols.

[0099] Depending on the implementation, the FT 205 may convert symbols corresponding to the time domain blocks into blocks of constellation points by using a discrete Fourier transform (DFT) or a fast Fourier transform (FFT).

[0100] The demapper 207 may demap blocks of constellation points to demap the data bits. If LDPC encoding is used, the demapper 207 may also perform LDPC tone demapping before constellation demapping.

[0101] The deinterleaver 209 may deinterleave the demapped data bits to generate deinterleaved data bits. In some embodiments, when BCC encoding is used, deinterleaving may be applied.

[0102] 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.

[0103] The descrambler 213 may descramble the descrambled data bits based on the scrambler seed.

[0104] Hereinafter, a multi-link operation (MLO) according to an embodiment will be described.

[0105] The IEEE802.11be 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 to enhance user experience. One of the key features of the IEEE802.11be standard is Multi-Link Operation (MLO). Since most AP STAs and non-AP STAs combine dual-band or tri-band capabilities, the newly developed MLO feature can achieve packet-level link aggregation across different PHY links in the MAC layer. By performing load balancing based on traffic requirements, MLO can achieve significantly higher throughput and lower latency to enhance reliability in heavily loaded networks. Using the MLO capability, a multi-link device (MLD) includes multiple attached devices to a higher logical link control (LLC) layer, allowing data transmission and reception in multiple channels simultaneously across single or multiple bands in 2.4 GHz, 5 GHz, and 6 GHz.

[0106] There is a Wi-Fi technology that allows Wi-Fi devices to connect to a single link and enables Wi-Fi devices to switch between 2.4GHz, 5GHz, and 6GHz bands. However, such Wi-Fi devices typically have a switching overhead or delay of up to 100ms. Therefore, MLO is highly desirable for real-time applications such as video calls, wireless VR headsets, cloud games, and other delay-sensitive applications. The IEEE802.11be draft specification defines different channel access methods according to two transmission modes: asynchronous mode and synchronous mode. In asynchronous transmission mode, MLD transmits frames asynchronously across multiple links without aligning the start time. In contrast, in synchronous transmission mode, the start time is aligned across links. In either mode, the link may have its own primary channel and parameters, including packet protocol data unit (PPDU), modulation and coding scheme (MCS), enhanced distributed channel access (EDCA), etc.

[0107] Figure 8 Multi-link operation (MLO) in synchronous transfer mode according to an embodiment is shown.

[0108] refer to Figure 8 , AP MLD 801 may include multiple APs, including AP1 and AP2, and non-AP MLD may include multiple STAs, including STA1 and STA2. AP1 may have a buffer containing data units, including data units to be sent to STA1; AP2 may have a buffer containing data units, including data units to be sent to STA2; STA1 may have a buffer containing data units, including data units to be sent to AP1; STA2 may have a buffer containing data units, including data units to be sent to AP2.

[0109] STA2 of non-AP MLD 803 may check whether the backoff counter of link L2 reaches 0. When the backoff counter of link L2 reaches 0, STA2 of non-AP MLD 803 may send data unit 811 to AP2 via link L2. AP2 of AP MLD 801 may send an Ack frame 813 for data unit 811 to STA2 via link L2a SIFS after AP2 successfully receives data unit 811.

[0110] Even during the reception of the data unit 811 by AP2, the AP1 of the AP MLD 801 may check whether the backoff counter of the link L1 reaches 0. When the backoff counter of the link L1 reaches 0, the AP1 of the AP MLD 801 may send the data unit 815 to the STA1 via the link L1 even during the reception of the data unit 811 by AP2. After the STA1 successfully receives the data unit 815, the STA1 of the non-AP MLD 803 may send an Ack frame 817 for the data unit 815 to the AP1 via the link L1 a SIFS.

[0111] exist Figure 8 In the embodiment of FIG. 8 , the AP MLD 801 may first complete receiving the data unit 811 via the link L2, and then the non-AP MLD 803 may complete receiving the data unit 815 via the link L1.

[0112] Hereinafter, exemplary topologies for relay operation scenarios according to embodiments will be described.

[0113] Fig. 9 An exemplary topology for a relay operation scenario according to an embodiment is shown.

[0114] Fig. 9 The wireless network shown in FIG. 1 includes multiple AP1, AP2, and AP3 and multiple STA1, STA2, STA3, and STA4. AP2 and AP3 are neighboring APs of AP1. Each AP can perform association with a STA and form its own BSS. Each AP can send data to an associated STA and can receive data from an associated STA.

[0115] refer to Fig. 9 , AP1, AP2 and AP3 form BSS1, BSS2 and BSS3 respectively. AP1 is associated with STA1, STA2, STA3 and STA4.

[0116] If the link quality or channel status between a STA within a BSS and an AP associated with the STA becomes poor, a relay operation to improve communication quality may be considered. In some embodiments, a relay operation may be performed using a neighboring AP as a relay device.

[0117] In the following, reference will be made to Fig.10 Channel (link) measurement between a STA and a neighboring AP according to an embodiment is described.

[0118] Fig.10 Channel measurement between a STA and a neighboring AP according to an embodiment is shown.

[0119] AP1 has data to be sent to STA1 in the buffer. If the link quality between AP1 and STA1 is not good, AP1 may not use a high MCS index and a high number of spatial streams (Nss) to send data to STA1. This is because if AP1 sends data using a high MCS index and a high Nss, STA1 may not successfully receive the data sent by AP1. In this scenario, if a relay operation is used, AP1 may use a high MCS and Nss to send data to STA 1. AP1, which attempts to send data to the STA, plays the role of a control AP (C-AP) that controls the relay operation. The APs among the neighboring APs AP2 and AP3 may play the role of a relay AP (R-AP) that has a good link quality or channel state with a STA (STA1) associated with the C-AP. The C-AP may receive a report from STA1 associated with the C-AP. In some embodiments, the report may include channel information measured by STA1 from a signal sent by a neighboring AP. In some embodiments, the channel information may include signal strength and / or channel state information (CSI) measured by STA1 from a signal sent by a neighboring AP. The C-AP may select an R-AP among neighboring APs based on the reported information and perform a relay operation by using the R-AP.

[0120] At 1001, the C-AP transmits a measurement announcement frame. In some embodiments, the measurement announcement frame may be addressed to STA1 and neighboring APs AP2 and AP3. In some embodiments, the measurement announcement frame may include an indication indicating that STA1 receives a signal transmitted by neighboring APs AP2 and AP3 and measures channel information. In some embodiments, the measurement announcement frame may include an indication indicating that neighboring APs AP2 and AP3 transmit a PPDU (e.g., NDP), so that STA1 can measure channel information by using the PPDU transmitted by neighboring APs AP2 and AP3. In some embodiments, the measurement announcement frame may include information indicating when neighboring APs AP2 and AP3 start transmitting PPDUs. In some embodiments, the measurement announcement frame may include at least one of information indicating one or more neighboring access points transmitting training frames, information indicating a station transmitting a measurement report frame in response to the measurement announcement frame, information indicating when one or more neighboring access points transmit training frames, and information indicating when a station transmits a measurement report frame. In some embodiments, the training frame may be a null data PPDU (NDP).

[0121] In response to the measurement announcement frame, neighboring APs AP2 and AP3 transmit PPDUs, such as NDPs indicated by the measurement announcement frame. In some embodiments, according to the measurement announcement frame, at 1003, neighboring AP2 transmits a PPDU SIFS after receiving the measurement announcement frame. At 1005, AP3 transmits a PPDU SIFS after AP2 transmits the PPDU.

[0122] STA1 may independently receive the PPDU transmitted by AP2 and AP3, and measure channel information based on the PPDU. At 1007, STA1 transmits a measurement report frame including channel information of neighboring APs to the C-AP.

[0123] After receiving the measurement report frame, the C-AP may select an R-AP according to the information in the measurement report frame. In some embodiments, the C-AP may configure a relay AP group that can be used for relay transmission, and include the selected R-AP in the relay AP group. In some embodiments, the C-AP may perform the same operation as other STAs associated with the C-AP, and configure the relay AP group based on the measurement results reported by the STA.

[0124] Fig.11 An exemplary topology for a relay operation scenario according to an embodiment is shown.

[0125] As mentioned above Fig.10 As described, when the channel state or link quality between C-AP and STA1 deteriorates and it is difficult to achieve high throughput by using high MCS and Nss, C-AP can use relay operation to send data to STA1. Among the APs in the relay AP group, C-AP selects an AP that can send a signal with the maximum signal strength to STA1. The selected AP can become an R-AP participating in relay transmission.

[0126] refer to Fig.11 , C-AP selects AP2 as the R-AP because the signal received by STA1 from AP2 has the maximum signal strength among the signals received by STA1 from the neighboring APs.

[0127] In the following, reference will be made to Fig.12 C-AP data transmission through an R-AP according to an embodiment is described.

[0128] Fig.12 An exemplary data transmission through a relay AP according to an embodiment is shown.

[0129] refer to Fig.12 , AP1 functions as a C-AP, and AP2 is selected to function as a R-AP.

[0130] If the C-AP has data to send to STA1, then at 1201, the C-AP may send PPDU1 including the data to the R-AP.

[0131] At 1203, in response to PPDU1 from the C-AP, the R-AP sends PPDU2 SIFS after receiving PPDU1 from the C-AP. PPDU2 sent by the R-AP includes the data in PPDU1. In some embodiments, PPDU2 may be the same as PPDU1. In some embodiments, PPDU2 may be PPDU1 including an acknowledgment (ACK) frame. PPDU2 is addressed to STA1. In some embodiments, the ACK frame included in the PPDU sent by the R-AP may be addressed to the C-AP to indicate that the R-AP successfully received the PPDU sent by the C-AP. In some embodiments, the preamble of PPDU2 may be the same as the preamble of PPDU1. In some embodiments, the MAC header of PPDU2 may be the same as the MAC header of PPDU1.

[0132] At 1205, in response to PPDU2 received from R-AP, STA1 transmits an ACK frame to C-AP SIFS after receiving PPDU2. The ACK frame is addressed to C-AP to indicate that STA1 successfully received PPDU1 via R-AP. In some embodiments, the ack frame may be sent using MCS0 which is the lowest MCS index.

[0133] Hereinafter, a roaming procedure based on a relay operation according to an embodiment will be described.

[0134] Upon successfully receiving PPDU1 transmitted from the R-AP, STA1 may perform roaming from AP1 to AP2 to change the AP associated with STA1.

[0135] Since the link quality between STA1 and AP2 is better than that between STA1 and C-AP, it may be more beneficial to roam from C-AP to R-AP after performing a new association with R-AP and configuration of a new BSS with R-AP.

[0136] For roaming based on relay operation, when C-AP instructs STA1 to measure the signal of a neighboring AP, C-AP may request STA1 to send information to other APs indicating whether STA1 has a preference for roaming. When STA1 reports the measurement result to C-AP, STA1 may inform C-AP which AP is suitable for roaming between neighboring APs. When C-AP sends a data PPDU to STA1 via relay transmission, C-AP may include information in the data PPDU notifying STA1 that the AP is a roaming AP after relay transmission. After the relay transmission is completed, STA1 may perform roaming according to the instruction in the PPDU received from the relay transmission to change the AP associated with STA1.

[0137] Fig.13Channel measurement between a STA and a neighboring AP according to an embodiment is shown.

[0138] refer to Fig.13 , AP1 functions as a C-AP.

[0139] At 1301, the C-AP transmits a measurement announcement frame. In some embodiments, the measurement announcement frame may be addressed to STA1 and neighboring APs AP2 and AP3. In some embodiments, the measurement announcement frame may include an indication indicating that STA1 receives a signal transmitted by neighboring APs AP2 and AP3 and measures channel information. In some embodiments, the measurement announcement frame may include an indication indicating that neighboring APs AP2 and AP3 transmit a PPDU (e.g., NDP), so that STA1 can measure channel information by using the PPDU transmitted by neighboring APs AP2 and AP3. In some embodiments, the measurement announcement frame may include information indicating when neighboring APs AP2 and AP3 start to send PPDUs. In some embodiments, the measurement announcement frame may include at least one of the following: information indicating one or more neighboring access points that transmit training frames, information indicating a station that transmits a measurement report frame in response to the measurement announcement frame, information indicating when one or more neighboring access points transmit training frames, and information indicating when a station transmits a measurement report frame. In some embodiments, the measurement announcement frame may include a roaming preference request field indicating that the C-AP requests STA1 to include a roaming preference report field in the measurement report frame, the roaming preference report field indicating whether STA1 has a preference to roam to other APs.

[0140] In response to the measurement announcement frame, neighboring APs AP2 and AP3 send PPDUs, such as NDPs indicated by the measurement announcement frame. In some embodiments, according to the measurement announcement frame, at 1303, neighboring AP2 sends a PPDU SIFS after receiving the measurement announcement frame. At 1305, AP3 sends a PPDU SIFS after AP2 sends the PPDU.

[0141] STA1 may independently receive the PPDU sent by AP2 and AP3, and measure channel information based on the PPDU. At 1307, STA1 sends a measurement report frame including channel information of the neighboring AP to the C-AP. In some embodiments, the measurement report frame may include a roaming preference report field. The roaming preference report field may indicate information indicating that STA1 has a preference for roaming to another AP among the neighboring APs or information indicating that STA1 wants to roam to an AP among the neighboring APs that sends a signal with the highest signal strength to STA1.

[0142] After the C-AP receives the measurement report frame, it may select an R-AP based on the information in the measurement report frame. In some embodiments, the C-AP may configure a relay AP group that can be used for relay transmission, and include the selected R-AP in the relay AP group. In some embodiments, the C-AP may perform the same operation as other STAs associated with the C-AP, and configure the relay AP group based on the measurement results reported by the STA.

[0143] Fig.14 An exemplary data transmission through a relay AP according to an embodiment is shown.

[0144] refer to Fig.14 , AP1 functions as a C-AP and AP2 is selected to function as an R-AP.

[0145] If the C-AP has data to send to STA1, then at 1401, the C-AP may send PPDU1 including the data to the R-AP. In some embodiments, PPDU1 may include a Roam to Other AP field. In some embodiments, the Roam to Other AP field may include information indicating that STA1 roams to other APs after sending an ACK frame to the C-AP or after relay transmission. In some embodiments, the Roam to Other AP field may include information indicating that STA1 roams to an AP to which STA1 wants to roam. In some embodiments, the Roam to Other AP field may include an indication or identification of an AP to which STA1 should roam after sending an ACK frame to the C-AP or after relay transmission. In some embodiments, the Roam to Other AP field may include information indicating that STA1 roams to an R-AP after sending an ACK frame to the C-AP or after relay transmission.

[0146] At 1403, in response to PPDU1 from the C-AP, the R-AP sends PPDU2 SIFS after receiving PPDU1 from the C-AP. The PPDU2 sent by the R-AP includes the data in PPDU1. In some embodiments, PPDU 2 may be the same as PPDU 1. In some embodiments, PPDU2 may be PPDU 1 including an acknowledgement (ACK) frame. PPDU2 is addressed to STA1. In some embodiments, the ACK frame included in the PPDU sent by the R-AP may be addressed to the C-AP to indicate that the R-AP successfully received the PPDU sent by the C-AP. In some embodiments, the preamble of PPDU 2 may be the same as the preamble of PPDU 1. In some embodiments, the MAC header of PPDU 2 may be the same as the MAC header of PPDU 1.

[0147] At 1405, in response to PPDU 2 received from R-AP, STA 1 transmits an ACK frame to C-AP SIFS after receiving PPDU 2. The ACK frame is addressed to C-AP to indicate that STA 1 successfully received PPDU 1 via R-AP. In some embodiments, MCS 0 may be used to send the ack frame.

[0148] Fig.15 An exemplary topology change after roaming based on relay operation according to an embodiment is shown.

[0149] like Fig.15 As shown, after STA 1 roams based on the relay operation from AP 1 to AP 2, STA 1 is associated with AP 2, and AP 2 functions as a C-AP.

[0150] The various exemplary blocks, units, modules, components, methods, operations, instructions, projects, and algorithms may be implemented or performed by processing circuitry.

[0151] Unless otherwise specified, reference to an element in the singular is not intended to mean one and only one, but rather one or more. For example, "a" module may refer to one or more modules. An element following "a", "an", "the" or "said" does not exclude the presence of additional identical elements without further constraints.

[0152] Headings and subheadings, if any, are used for convenience only 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 "including," "having," "carrying," "comprising," 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 used as a transitional word in a claim. Relational terms such as first and second, and the like 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.

[0153] Phrases such as on the one hand, this aspect, on the other hand, some aspects, one or more aspects, an embodiment, this embodiment, another embodiment, some embodiments, one or more embodiments, an example, this example, another example, some examples, one or more examples, a configuration, this configuration, another configuration, some configurations, one or more configurations, subject technology, the disclosure, the present disclosure, other variations thereof, etc. are for convenience and do not imply that the disclosure associated with such phrases is essential to the subject technology or that such disclosure applies to all configurations of the subject technology. The disclosure associated with such phrases may apply to all configurations or one or more configurations. Disclosures involving such phrases may provide one or more examples. Phrases such as one or more aspects may refer to one or more aspects and vice versa, and this applies similarly to the other aforementioned phrases.

[0154] The phrase "at least one of" preceding a list of items (with the terms "and" or "or" separating any of the items) modifies the list as a whole, rather than each member of the list. The phrase "at least one of" does not require selection of at least one of the items; rather, the phrase permits a meaning that includes at least one of any one 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" means only A, only B, or only C; any combination of A, B, and C; and / or at least one of each of A, B, and C.

[0155] It should be understood that the specific order or hierarchy of the disclosed steps, operations or processes is a diagram 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 serially, linearly, in parallel or in different orders. It should be understood that the instructions, operations and systems described can usually be integrated together in a single software / hardware product or packaged into multiple software / hardware products.

[0156] The present disclosure is provided to enable those skilled in the art to practice the various aspects described herein. In some cases, well-known structures and components are shown in block diagram form to avoid blurring the concept 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 apparent to those skilled in the art, and the principles described herein may be applied to other aspects.

[0157] All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later become known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. In addition, the disclosure herein is not intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. A claim element is not to be interpreted under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is explicitly recited using the phrase means, or, in the case of a method claim, the element is recited using the phrase step.

[0158] The title, background, brief description of the drawings, abstract and drawings are incorporated into the present disclosure and are provided as illustrative examples of the present disclosure, rather than as limiting descriptions. It should be understood that they will not be used to limit the scope or meaning of the claims. In addition, in the detailed description, it can be seen that the description provides illustrative examples, and for the purpose of simplifying the present disclosure, various features are grouped together in various embodiments. The method of the present 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 attached claims, the inventive subject matter lies in less than all the features of a single disclosed configuration or operation. The attached claims are incorporated into the detailed description here, wherein each claim is independently a subject matter claimed separately.

[0159] 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 of the claims and encompass all legal equivalents. Nevertheless, the claims are not intended to encompass subject matter that does not satisfy the requirements of applicable patent law, nor should they be interpreted in such a manner.

Claims

1. A wireless communication device for facilitating wireless communication, comprising a processing circuit configured to facilitate: Sending a measurement advertisement frame addressed to one or more neighboring access points and stations, where: The measurement announcement frame triggers the one or more neighboring access points to send a training frame to the station, and triggers the station to measure channel information based on the training frame from the one or more neighboring access points; receiving a measurement report frame from the station, wherein the measurement report frame includes the channel information; determining a relay access point based on the measurement report frame; as well as A first data unit is sent to the station via the relay access point.

2. The wireless communication device according to claim 1, wherein: Sending the first data unit to the station via the relay access point includes: The first data unit is sent to the relay access point to trigger the relay access point to generate a second data unit based on the first data unit and send the second data unit to the station.

3. The wireless communication device according to claim 2, wherein: The processing circuitry is further configured to cause: An acknowledgement frame is received from the station indicating that the station has successfully received the second data unit via the relay access point.

4. The wireless communication device according to claim 3, wherein: The acknowledgement frame is modulated and coded based on a lowest modulation and coding scheme MCS index.

5. The wireless communication device according to claim 2, wherein: The second data unit comprises an acknowledgment frame, The confirmation frame is used to notify the wireless communication device that the relay access point has successfully received the first data unit.

6. The wireless communication device according to claim 1, wherein: The measurement notification frame includes: information indicating the one or more neighboring access points that sent the training frame, and Information indicating the station that sends the measurement report frame in response to the measurement notification frame.

7. The wireless communication device according to claim 1, wherein: The measurement notification frame includes: information indicating when the one or more neighboring access points transmit the training frames, and Information indicating when the station sends the measurement report frame.

8. The wireless communication device according to claim 1, wherein: The measurement notification frame includes information indicating the following: The station is requested to include, in the measurement report frame, information indicating whether the station is inclined to change an access point associated with the station after a relay operation.

9. The wireless communication device according to claim 1, wherein: The measurement report frame has information indicating that the station wants to change an access point associated with the station after a relay operation.

10. The wireless communication device according to claim 1, wherein: The first data unit includes information for instructing the station to change an access point associated with the station after the station sends an acknowledgment frame for the first data unit.

11. A wireless communication device for facilitating wireless communication, comprising processing circuitry configured to cause: receiving, from an associated access point, a measurement advertisement frame addressed to one or more neighboring access points and stations, wherein: The associated access point causes the first data unit to be addressed to the wireless communication device, the measurement announcement frame triggers the one or more neighboring access points to send a training frame to the station, and triggers the station to measure channel information based on the training frame from the one or more neighboring access points; Sending a measurement report frame to the associated access point, where the measurement report frame includes the channel information; as well as A second data unit is received from a relay access point determined based on the measurement report frame, the second data unit being generated by the relay access point based on the first data unit.

12. The wireless communication device according to claim 11, wherein: The processing circuitry is further configured to cause: An acknowledgement frame is sent to the associated access point indicating that the station has successfully received the second data unit via the relay access point.

13. The wireless communication device according to claim 12, wherein: The acknowledgement frame is modulated and coded based on a lowest modulation and coding scheme MCS index.

14. The wireless communication device according to claim 11, wherein: The second data unit comprises an acknowledgment frame, The confirmation frame is used to notify the associated access point that the relay access point has successfully received the first data unit.

15. The wireless communication device according to claim 11, wherein: The measurement notification frame includes: information indicating the one or more neighboring access points that sent the training frame; and Information indicating the station that sends the measurement report frame in response to the measurement notification frame.

16. The wireless communication device according to claim 11, wherein: The measurement notification frame includes: information indicating when the one or more neighboring access points transmit the training frames; and Information indicating when the station sends the measurement report frame.

17. The wireless communication device according to claim 11, wherein: The measurement notification frame includes information indicating the following: The station is requested to include, in the measurement report frame, information indicating whether the station is inclined to change an access point associated with the station after a relay operation.

18. The wireless communication device according to claim 11, wherein: The measurement report frame has information indicating that the station wants to change an access point associated with the station after a relay operation.

19. The wireless communication device according to claim 11, wherein: The first data unit includes information for instructing the station to change an access point associated with the station after the station sends an acknowledgment frame for the first data unit.

20. The wireless communication device according to claim 11, wherein: The training frame is a null data physical layer PHY protocol data unit PPDU.

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