Multilink device and method

Abstract

To provide a multi-link device that consumes less power and is simpler than conventional multi-link devices, especially in a scenario where data is exchanged between multi-link devices. [Solution] A first multilink device comprises a first station having a transmitter and a receiver and configured to communicate with a first station of a second multilink device over a first link, a second station having no transmitter but a receiver and configured to receive data from other first stations of the second multilink device over a second link different from the first link, and circuitry configured to control the first station and the second station, and the second station configured to provide the received data to the circuitry and / or the first station.

Description

[Technical field]

[0001] The present disclosure relates to first and second multilink devices and corresponding methods. [Background technology]

[0002] A Multi-Link Device (MLD) combines multiple Stations (STAs), each operating on a specific link, to achieve higher throughput and / or lower latency compared to a single-link device. In general, it is desirable to have as many links as possible. However, since each link requires an associated STA in the MLD, the number of STAs increases with the number of links. This makes the chipsets larger, more expensive, and / or more power-hungry compared to single STA chipsets, which is especially problematic for consumer non-Access Point (non-AP) MLD devices.

[0003] The "Background" discussion provided herein is intended to generally provide a context for the present disclosure. The work of the currently named inventor(s) (to the extent described in the Background section) and aspects of the description that may not be admitted as prior art at the time of filing this application are not admitted, expressly or impliedly, as prior art to the present disclosure. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to provide a multi-link device that consumes less power and is simpler than conventional multi-link devices, especially in a scenario of exchanging data between multi-link devices. The present invention also aims to provide a corresponding method, a corresponding computer program for implementing the method, and a non-transitory computer-readable recording medium for implementing the method. [Means for solving the problem]

[0005] According to one aspect, a first multilink device, comprising: a first station comprising a transmitter and a receiver and configured to communicate with a first station of a second multilink device over a first link; a second station not comprising a transmitter but comprising a receiver and adapted to receive data from other first stations of the second multilink device on a second link different from the first link; - a circuit configured to control the first station and the second station; Equipped with The second station is provided with a first multilink device configured to provide the received data to the circuit and / or the first station.

[0006] According to a further aspect, a second multilink device, - two or more first stations, each comprising a transmitter and a receiver and each configured to communicate with a first station or a second station of a first multilink device, one of the first stations communicating with the first station of the first multilink device over a first link and another of the first stations transmitting to a second station of the first multilink device over a second link, the second station of the first multilink device not comprising a transmitter but comprising a receiver; - circuitry configured to control the two or more first stations; A second multilink device is provided, comprising:

[0007] According to other further aspects, there is provided a corresponding method, a computer program comprising program means which, when executed on a computer, causes the computer to perform the steps of the method described herein, and a non-transitory computer readable recording medium storing a computer program product which, when executed by a processor, causes the computer to perform the method described herein.

[0008] Each embodiment is defined in the dependent claims. It is understood that the disclosed method, the disclosed computer program and the disclosed computer-readable recording medium have further embodiments similar and / or identical to the claimed device, which are defined in the dependent claims and / or disclosed herein.

[0009] One aspect of the present disclosure is to include a receiving STA (herein referred to as a "second station" or "Rx STA") in the MLD (herein referred to as a "first multilink device" or "non-AP MLD"), i.e., a STA that can only receive and not transmit. In contrast to a normal STA, the receiving STA can operate at significantly lower power and is less complex. The receiving STA can assist the MLD to receive data. It can also set up a link to the receiving STA and transmit data with the receiving STA in an advantageous manner.

[0010] It should be noted that in this context, "data" shall be broadly interpreted as any kind of data originating from a user (user data) or from the communication system itself (management data). In general, user data originates from the upper layers of the communication device (e.g., application layer) and should be distributed to the upper layers of the communication device, while management data originates from the communication device and its peers and should be distributed to the peers of the communication device. User data often requires a response, such as a positive or negative acknowledgement of receipt. However, in special cases, the response to user data may be omitted if the sender wishes. With respect to management data, management data requiring a response is considered in this specification. Information transmitted in a data frame, for example according to IEEE 802.11, etc., which may require a response, shall be interpreted as data. Furthermore, information transmitted in a management frame, for example according to IEEE 802.11, which requires a response, shall be interpreted as data as well.

[0011] The preceding paragraphs have been provided by way of general introduction and are not intended to limit the scope of the claims which follow. The described embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings, in which:

[0012] The present disclosure and many of the attendant advantages thereof will be readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, in which: [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram of a conventional MLD operating with two links. [Diagram 2] 1 is a schematic diagram of the control plane of MLD. [Figure 3A] FIG. 2 is a schematic diagram of one embodiment of an AP MLD and a non-AP MLD according to the present disclosure. [Figure 3B]FIG. 2 is a schematic diagram of one embodiment of an AP MLD and a non-AP MLD according to the present disclosure. [Figure 4A] 1 illustrates one embodiment of a non-AP MLD according to the present disclosure. [Figure 4B] 1 illustrates one embodiment of a non-AP MLD according to the present disclosure. [Diagram 5] 13 is a flowchart of a setup phase from the perspective of a non-AP MLD according to the present disclosure. [Figure 6] FIG. 2 is a schematic diagram of an exemplary MLD setup between an AP MLD and a non-AP MLD according to the present disclosure. [Figure 7] FIG. 7 is a diagram illustrating frame exchange between the AP MLD and non-AP MLD shown in FIG. 6. [Figure 8] FIG. 13 illustrates an acknowledgment timeout assuming a non-zero propagation delay in the receive state. [Figure 9] FIG. 13 is another diagram illustrating the acknowledgement timeout assuming a non-zero propagation delay in the receive state. [Figure 10] FIG. 13 illustrates another option for minimizing the time to acknowledgement. [Figure 11] 11 is an explanatory diagram of a case where an AP STA waits for distribution of a reception status. [Figure 12] 13 is a diagram illustrating a case where an AP STA continues accessing a link even though the reception status of an initial transmission is not received. FIG. [Figure 13] FIG. 2 is a schematic diagram of another exemplary MLD setup between an AP MLD and a non-AP MLD according to the present disclosure. [Figure 14] FIG. 1 illustrates how a data receiving Rx STA contributes to low latency data delivery. [Figure 15] 1 is a schematic diagram of an exemplary MLD setup, showing the flow of control information; [Figure 16] 13 is a diagram illustrating parameter extraction from a legacy header of a received PPDU. [Figure 17] 3 illustrates link state information detection via observation channel energy and / or preamble detection. [Figure 18] 11 is a diagram illustrating link switching based on link state information of an Rx STA. FIG. [Figure 19A] A diagram showing Enhanced Single Radio operation by an Rx STA. [Figure 19B] A diagram showing Enhanced Single Radio operation by an Rx STA. [Figure 19C] A diagram showing Enhanced Single Radio operation by an Rx STA. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Referring now to the drawings, where like reference numerals denote the same or corresponding parts throughout the several views, FIG. 1 is a schematic diagram showing two Multi-Link Devices (MLDs) 10, 20 operating on two links (Multi-Link Operation (MLO)). The MLD consists of multiple cooperating stations (STAs), either AP STAs (Access Point STAs) 11, 12 or non-AP STAs 21, 22. Each STA consists of a transmitter and receiver PHY (Physical Layer) that allows bidirectional data exchange in Time Division Duplex (TDD), and a lower Media Access Control (MAC) sublayer. Within the MLD, the upper MAC sublayer 13, 23 converges the data flow of both links. Typically, each STA operates on a different channel, thereby forming a bidirectional link between each AP STA 11, 12 and the non-AP STAs 21, 22 as shown in FIG. 1. Communication over the different links may or may not occur simultaneously, depending on the capabilities of both the AP MLD 10 and the non-AP MLD 20. Figure 1 also shows a non-MLD non-AP STA 30 that can connect to the AP MLD 10 over a single link via the AP STA 11. The non-AP STA 31 and the upper MAC layer 33 of the non-MLD 30 are often combined and referred to as a non-AP STA.

[0015] In the MLD, each associated STA often operates independently with respect to PHY and lower MAC processing. However, the upper MAC processing is shared between both STAs. Figure 2 is a schematic diagram of the control plane of the MLD. Each STA 11, 12, 21, 22, 31 has a control unit 14, 15, 24, 25, 36 that controls the STA, the lower and upper MAC sublayers 13, 23, 33. The MLD also has a Station Management Entity (SME) 16, 26, 36 (or central control unit) that controls the control units of all associated STAs. The SME performs its control tasks to ensure that the upper MAC sublayer operates properly. The SME may also perform other tasks that are not related to PHY or MAC but are related to the upper layers.

[0016] In general, it is desirable to have as many links as possible to reduce channel access delays, i.e., to allow the first idle link to be used for data exchange, to improve throughput, i.e., the throughput of each link accumulates, and to improve availability, i.e., the more links there are, the more likely they are to be idle. However, since each link requires an associated STA in the MLD, the number of STAs increases with the number of links. This makes the chipsets larger, more expensive, and / or more power-hungry compared to single STA chipsets, which is particularly problematic for consumer non-AP MLD devices.

[0017] The reason this issue occurs is because each STA is a normal STA and supports all the capabilities it has, including sending and receiving various frames at different rates, bandwidths, streams, etc. These capabilities are always supported, regardless of whether they are currently in use or not. These capabilities can be temporarily disabled by power saving techniques, but they are still present and deployed, and the disabled capabilities have no function while in power saving mode.

[0018] Furthermore, link switching, i.e., a STA switching from a first link to a second link, creates overhead and requires the STA to observe the wireless medium for a certain time interval (also referred to herein as a minimum observation period) before accessing the channel. Furthermore, if the STA is an AP STA, the STA needs to notify associated STAs about the link switch in advance or disassociate these STAs. Thus, link switching is not an option to reduce channel access delay. Furthermore, the link state ("busy" or "idle") of the link to which the STA plans to switch is not clear before the switching operation. Thus, the STA may switch to the second link, which is in a less favorable state than the first link.

[0019] According to the present disclosure, as part of the MLD, an Rx STA is provided. The Rx STA is a receive-only STA, i.e., it cannot transmit but only receives. To further save power, the receiving capability may be limited, in the sense that the supported PHY configurations and / or MAC frames are very sparse. The Rx STA is typically a low-complexity, low-power STA. Therefore, the deployment of the Rx STA is less of an implementation burden than a conventional STA. In contrast, the gains achieved by the Rx STA are lower compared to conventional STAs, but still high.

[0020] 3A is a schematic diagram of an embodiment of an AP MLD 40 according to the present disclosure, and FIG. 3B is a schematic diagram of an embodiment of a non-AP MLD 50 according to the present disclosure. Each of the MLDs 40 and 50 (also referred to herein as a "first multilink device" or "first MLD") comprises one or more (regular) STAs 41, 51 (having transmit and receive capabilities, also referred to herein as a "first STA") and at least one (associated) Rx STA 42, 52 (having only receive capabilities, also referred to herein as a "second STA"). As shown in FIGS. 1 and 2, an upper MAC sublayer 43, 53 may also be provided. The Rx STAs cannot exist alone, i.e., cannot exist other than as part of an MLD, because the missing transmit capabilities are essential for communication, even if data or other information is only received, as described below. The Rx STA may be part of an AP MLD or a non-AP MLD, and may be more beneficial in a non-AP MLD where power savings and cost are paramount. The Rx STA may generally provide control information and / or data to the MLD. Thus, connection C1 shown in FIG. 3, which illustrates the data flow, may or may not be present, and in particular, is present only if the Rx STA provides data to the MLD.

[0021] Figure 4 shows an embodiment of the non-AP MLDs 50A, 50B in more detail. As shown in Figure 2, control units 54, 55 and SME 56 are also provided (one or more of elements 53-56 are also referred to herein as "circuitry"). Note that in some embodiments, the signal processing blocks "upper MAC layer", specifically labeled 43, 53, 63 in the figure, can be considered to be part of the circuitry referred to herein.

[0022] 4A shows the case where Rx STA 52 provides control information to the MLD via connection C3. The main purpose of connection C3 towards Rx STA 52 is to configure the receiver of the Rx STA (e.g., configure the channel (i.e. link) to observe), and the main purpose of connection C3 towards control unit 55 is to provide control information to SME 56 and / or control unit 54 and / or upper MAC sublayer 53. Connection C2 may or may not be present, in which case upper MAC sublayer 53 is controlled via SME 56 and control unit 54.

[0023] FIG. 4B shows the case where the Rx STA 52 provides data to the MLD. Control information exchanged over connection C5 provides for the configuration of the Rx STA's receiver (towards the Rx STA 52) and for acknowledgement (from the Rx STA 52). As with connection C2, connection C4 may or may not be present. Often, connection C4 may be required for control of the upper MAC sublayer 53 to insert received data into the data stream. As described below, a control link from the Rx STA 52 to the non-AP STA 51 and / or in the opposite direction, for example via the upper MAC sublayer 53 or SME 62, may be important for operation. A direct link (shown as a dotted line in FIG. 4B) may also be provided. One (but not necessarily only one) purpose of the control link from Rx STA52 to non-AP STA51, whether routed through the upper MAC sublayer / SME or directly, is to deliver acknowledgments to data received by Rx STA52 and / or relay data or control information to the AP MLD (second MLD), as described in more detail below.

[0024] In the following, the case where the Rx STA provides received data to the MLD as provided according to the first aspect of the present disclosure will be described. Figure 5 shows a flow chart of the setup phase 100 from the perspective of the non-AP MLD when the Rx STA should receive data. The setup phase 100 can have four sub-phases: discovery phase 101, association phase 102, agreement phase 103, and communication phase 104. The first two sub-phases of the setup phase 100 (discovery and association) may need to be performed if the Rx STA should only receive control information (as will be described later). Agreement 103 may also be used to agree on encryption parameters and observation links for EMLSR operation, for example.

[0025] During discovery phase 101, any associating non-AP STA of a non-AP MLD may collect information about the configuration of the AP MLD (step 101A). The non-AP MLD may control its associating Rx STAs to receive data from links provided by the AP MLD that are not provided by an associating non-AP STA of the same non-AP MLD (step 101B).

[0026] In a subsequent association phase 102, the non-AP STAs associated with the non-AP MLD advertise the presence of the Rx STAs and, optionally, parameters and / or capabilities such as channel, bandwidth, supported PHY, MAC configuration, etc. Depending on the Rx STA implementation, the Rx STA may change its observation channel frequently. In this case, the non-AP STA must include a channel schedule when the Rx STAs associated with the same non-AP MLD will change their observation channel.

[0027] After the association phase 102, in an agreement phase 103, a non-AP STA associated with a non-AP MLD can participate in or establish agreements with its peer AP MLDs. These agreements may include, among others, one or more of the following: - BlockAck (BAck) agreement, which configures the use of BAck, such as scoreboard size. (BAck agreement for Rx STA is initiated by AP MLD when Rx STA receives on downlink), - A 4-way handshake to exchange encryption parameters to enable secure communication between the non-AP and the AP MLD. The Rx STA 4-way handshake is initiated by the AP MLD when the Rx STA receives on the downlink, and - TID (Traffic Identifier)-Link Mapping Request / Response initiated by AP MLD or non-AP MLD.

[0028] By default, all agreements apply to the link towards the Rx STAs as well. Optionally, different parameters may apply to the link towards the Rx STAs, in which case non-AP STAs associated with the same non-AP MLD establish separate agreements with their peer AP MLDs for this link.

[0029] Since the setup phase 100 requires data transmission (eg, for association), the Rx STA cannot exist alone but requires at least one normal STA, both of which are interconnected in the MLD.

[0030] 6 is a schematic diagram of an exemplary MLD setup between an AP MLD 60 (also referred to herein as a "second multilink device" or "second MLD") and a non-AP MLD 50 ("first MLD"). The AP MLD consists of two AP STAs 61, 62 (i.e., first stations with transmit and receive capabilities) and an upper MAC sublayer 63. Two links are established: link 1 between the AP STA 61 and the non-AP STA 51, and link 2 from the AP STA 62 to the Rx STA 52, and both STAs 51, 52 are associated with the same non-AP MLD 50.

[0031] Since the Rx STA52 is composed of only a receiver, it cannot transmit an Ack or BAck to the transmitter in response to one or more data. Therefore, data transmitted to the Rx STA52 does not require an acknowledgment or must have the AP STA61 of the same MLD60 associated with the transmitting AP STA62 transmit an acknowledgment (e.g., Back) via another link. Such an acknowledgment can include not only an acknowledgment of data transmitted to the Rx STA52, but also an acknowledgment of data transmitted to one or more non-AP STA51 associated with the same non-AP MLD50.

[0032] An AP STA 62 transmitting data for a certain TID will only transmit to the Rx STA 52 if an agreement on acknowledgment (e.g., a BAck agreement) has previously been established for that TID and that TID has been mapped to a receive-only link and at least one link provided by a non-AP STA 51 associated with the same non-AP MLD 50 as the Rx STA 52. This includes that sequence numbers for identifying data from the same TID originate from the same sequence number space for both the Rx STA 52's link and the link or links to the non-AP STA 51. Acknowledgments for data transmitted to the Rx STA 52 can only be delivered over links for which the TID of that data is valid.

[0033] FIG. 7 is a diagram showing frame exchange between the AP MLD 60 and the non-AP MLD 50 shown in FIG. 6. In this example, it is assumed that the AP STA2 (62) transmits data #2 and #3 to the Rx STA 52 and requests an Ack from both. After receiving both data, the reception status is forwarded to the non-AP STA1 (51) for inclusion in the next BAck sent to the AP MLD 60. In this example, it is assumed that the non-AP STA1 (51) transmits the next BAckB1 in response to receiving data #4 and #5. Also, the non-AP STA1 (51) may provide a BAck status based on the BAck request by the AP STA1 (61). In this way, the BAckB1 includes the reception status of data #2 to #5. Here, it is assumed that the data #2 to #5 are transmitted from the same TID. However, they may also be transmitted from different TIDs, in which case the BAckB1 holds the reception status of multiple TIDs. In the AP MLD 60, the reception status of data #2 and #3 is forwarded to the AP STA2 (62) for further consideration, e.g., retransmission, etc. The last step is optional, since the AP MLD 60 may decide to retransmit data #2 and #3, e.g., via link 1.

[0034] It may take time for the reception status of the Rx STA52 to propagate to the AP STA62 that sent the data. For this reason, the following method may be applied: A STA that sends one or more data requiring a response to the Rx STA52 assumes that the data did not arrive at the Rx STA52 or that such information does not exist before a first BAck arrives from the same MLD50 with which the Rx STA52 is associated indicating that the data has not arrived. The reception status of the data directed to the Rx STA52 shall be included in the next BAckB1 sent to the MLD50 with which the peer STA51 of the Rx STA52 is associated.

[0035] Note that in this context, the terms "first BAck" or "next BAck" are interpreted as the first or next acknowledgment (e.g., Back) after the end of the data-bearing PPDU, and may include the receive state propagation delay to account for the processing delay. The receive state propagation delay, if any, is indicated during the setup phase. Also note that a Back may be considered as a single acknowledgment that includes multiple acknowledgments.

[0036] 8 and 9 are diagrams illustrating the BAck timeout assuming that the propagation delay of the reception state is not zero. In FIG. 8, the first BAckB2 after the PPDU carrying data #2 and #3 is far after the reception state propagation delay, so the first BAckB2 can include the reception state of these data. In FIG. 9, the first BAckB3 after the PPDU carrying data #2 and #3 starts transmitting before the reception state propagation delay ends. Therefore, the reception state of data #2 and #3 can be included in the second BAckB4 transmitted from the cooperating non-AP STA 51.

[0037] The AP MLD 50 may request a BAck for a BAck response to minimize BAck timeout. Alternatively, the non-AP STA 60 may send an unsolicited, i.e., unsolicited, BAck. Thus, after the Rx STA 52 receives the data, the non-AP STA 51 may contend for channel access to send a BAck.

[0038] 10 illustrates another option for minimizing the time before the BAck response requires the AP STA61 to be informed of the reception state propagation delay. In such a case, the AP STA61 can include padding ("PAD") after the last data or add more data (e.g., data for other TIDs) to the PPDU. By extending the PPDU beyond the reception state propagation delay, the BAckB5 sent in response to the extended PPDU may already include the reception state of the data received by the Rx STA52.

[0039] Any STA operating in an unlicensed band must perform a Listen Before Talk (LBT), parameterized by a Contention Window (CW) value. When a STA receives data to transmit, it decrements a random backoff counter in the interval [0,CW]. The CW is selected depending on the previous transmission. If the previous transmission was successful, i.e., a response to the transmission was received, then CW=CW min otherwise, the CW is, for example, new =2·CW old The CW is incremented by +1, i.e., the CW is approximately doubled. The CW value is often specific to a particular Access Category (AC) queue to distinguish different priorities of data (e.g., voice, video, best effort, background). The CW value is managed (e.g., increased, initialized) on a per-AC basis.

[0040] When a response frame (e.g., BAck) is required and data is sent on the link toward the Rx STA, the AP STA in the AP MLD increments its CW for future transmissions unless the AP MLD receives an associated response over another link from a non-AP STA in the same non-AP MLD with which the Rx STA is associated, or the AP MLD receives a response over another link from a non-AP STA in the same MLD with which the Rx STA is associated. In this case, CW=CW min Hold.

[0041] In an exemplary embodiment, the CW values ​​addressed here are only valid for transmissions directed to Rx STAs and may be further differentiated per AC. This is advantageous because a response frame may be delayed due to a busy link carrying the BAck. If a regular CW were used, traffic to other regular STAs would be unnecessarily penalized.

[0042] FIG. 11 is a diagram illustrating the case where AP STA 62 waits for the reception status to be delivered over link 1 before resuming contention after the first transmission. The random backoff interval is always CW min Due to this implementation option, the "wait for receive state" phase may not be preserved for transmissions to normal STAs and / or Rx STAs using another AC.

[0043] If an AP STA has a FIFO ordered transmit queue, there are two options for implementing the "wait for receive state" phase. According to the first option, the AP STA checks the destination of the first data in its queue. If the destination is an Rx STA, a response is outstanding, and the BAck timeout has not yet elapsed, the AP STA does not initiate a backoff procedure, otherwise it does. According to the second option, the AP STA starts the backoff first, but checks the destination STA of the first data in the queue. If the destination is an Rx STA and a response is outstanding, the AP STA stops the backoff procedure and continues it when a response is received or the BAck timeout occurs.

[0044] FIG. 12 illustrates the case where AP STA2 (62) continues to access link 2 even though it has not yet received the reception status of the first transmission over link 1. As illustrated, the random backoff interval for the second transmission is 2CW. min +1 because the receive state of the initial transmission is unknown to the AP STA 62. When the receive state arrives at the associated AP STA 61 that has already started backing off for a future transmission, the AP STA 61 can either shorten the backoff, reinitialize the backoff, or continue to use the previous backoff.

[0045] The BAck sent from non-AP STA 51 does not include the reception status of data #6 and #7 because these data have not yet been received when the BAck is sent. Therefore, the third transmission by AP STA 62 is an interesting case because at the start, the reception status of data #2 and #3 is clear, but data #6 and #7 are unclear. In such a case, there are three options for initializing the CW value. - (as in Figure 12) CW min Initialize with - Initialize with the previous CW, i.e. with the CW as is (this is 2CW min +1), and -Increase CW and initialize (this is 4 CW min +3). The last option corresponds to the case where the transmission fails or partial reception is available but no reception is available. Therefore, the first and second options are more likely. This implementation option may result in the increase in CW not being preserved for transmissions to normal STAs and / or Rx STAs using another AC.

[0046] FIG. 13 is a schematic diagram of another exemplary MLD setup between an AP MLD 60 and a non-AP MLD 50. FIG. 14 is a diagram illustrating how a data receiving Rx STA 52 contributes to low latency data delivery. Link 1 is detected as busy for a long time. Since the Rx STA 52 can receive data on link 2, which is assumed to be idle, the AP MLD 60 can easily transmit latency sensitive data to the non-AP MLD 50. Acknowledgements for these data arrive at a later point in time over link 1. However, if correctly received, the data can be easily processed at the application layer of the non-AP MLD 50, although the reception status is unknown to the AP MLD 60.

[0047] In the following, the case where the Rx STA provides control information to the non-AP MLD as provided according to the second aspect of the present disclosure will be described. In the previous example, according to the first aspect, the reception status of data received from the Rx STA can be considered as the control information transferred from the Rx STA to its non-AP MLD. In contrast, according to the second aspect, control information is used that is obtained by the Rx STA by listening to the medium and is not related to data frames directed to the Rx STA. Such control information is often included in control or management frames (whether directed to the Rx STA or not) or in any PPDU directed to other STAs. In this variant, data frames are not directed to the Rx STA as unicast, but control frames (or management frames) may be directed to the Rx STA. As mentioned above, in this case, the first two or three phases (discovery and association) of FIG. 5 may be performed.

[0048] FIG. 15 is a schematic diagram of an exemplary MLD setup between an AP MLD 60 (e.g., as shown in FIG. 6, with additional elements 64-66 as provided in the AP MLD 10 shown in FIG. 2) and a non-AP MLD 50 (e.g., as shown in FIG. 4A and FIG. 4B), with the flow of control information illustrated. There are two sub-variants. In the first sub-variant, the control information obtained by the Rx STA 52 is used within the same MLD. The main control flow in this case is shown by the solid thick arrows. In the second sub-variant, the control information obtained by the Rx STA 52 is forwarded by the MLD to the AP MLD 60 via the non-AP STA 51 and the AP STA 61. This control information can be used in different contexts within the AP MLD 60, for example, channel busy information or OBSS information can trigger the AP MLD 60 to switch its link to a different channel. The information flow of the second sub-variant includes solid and dashed thick arrows. While the control information in the non-AP MLD 50 can be forwarded with little delay, forwarding to the AP MLD 60 can take longer due to channel access delays. Thus, in the latter case average values ​​of the observed parameters are appropriate, while in the former case instantaneous values ​​may also be forwarded.

[0049] The control information that the Rx STA 52 may obtain and provide to at least the associated non-AP MLD 50 may include: a) Link state or link information regarding one or more of the length of the currently received PPDU, the bandwidth of the received PPDU, the TXOP duration or NAV, the receive power, the BSS identifier (BSS color) of the currently received PPDU, and the Puncturing information of the currently received PPDU. These parameters can be extracted from the legacy header of the received PPDU or from the received control frames such as RTS or CTS, as shown in Figure 16. b) Link state information or link information regarding the current busy / idle state (Carrier Clear Assessment (CCA)) of the observed channel. This indication can be derived by energy and / or (WLAN) preamble detection of the observed channel as shown in Figure 17. There may be a small skew between received power and CCA. c) Channel state information regarding the impulse response and / or transfer function between the transmitter and Rx STA, determined from the received PPDU (often a Null Data Packet (NDP)). d) Operational advice information regarding receipt of control frames for configuring or reconfiguring non-AP MLD operation.

[0050] The information listed above can be used for various purposes. Assume that the non-AP MLD 50 wants to transmit data to the AP MLD 60. The control information of the Rx STA 52 can assist the non-AP STA 51 in this task. In particular, the Rx STA 52 can perform one or more of the following operations: i. Control non-AP STAs to steer to idle links. Such steering may be temporary, i.e., to achieve one or more frame exchanges with the peer MLD, or may be semi-permanent, i.e., for a longer period of time. Information a) and / or b) may help the non-AP MLD to make the decision. ii. A non-AP STA performs a CW countdown to transmit after the CW countdown. This causes the Rx STA to observe CCA (information b)), but the non-AP STA is switching to the link observed by the Rx STA, which may cause switching delays. For the CCA information to be correctly acquired, the bandwidth of the Rx STA and the non-AP STA must be the same or at least cover the primary (e.g., 20 MHz) channel of the link on which the CW countdown is performed. iii. Allow non-AP STAs to switch their links without or with a reduced media synchronization delay timer. In Multi-Link (ML) operation, if a non-AP STA wants to use another link that it has not observed or could not observe before, it needs to respect the timeout before transmitting anything. This is because the non-AP STAs collect information about the link medium, such as NAV. If the medium is continuously observed by the Rx STAs, the information collection is obsolete and thus the non-AP STAs may transmit immediately, i.e. ignoring the media synchronization delay, or after a shorter observation period, i.e., after a shorter media synchronization delay. Information a) and / or b) may be used for this operation. If the AP MLD initiates a link switch by a trigger frame (e.g., MU-RTS trigger frame), the trigger frame must be configured to perform carrier sense before the non-AP MLD accesses the medium.

[0051] The above three application examples are shown in FIG. 18, which describes link switching based on the link status information of the Rx STA. Here, assume that the non-AP MLD 50 wants to transmit data, but link 1 is busy. Based on the link status information obtained by the Rx STA 52, the non-AP STA 51 of the non-AP MLD 50 can switch to link 2 to perform frame exchange with the AP MLD 60. If the Rx STA 52 can perform CW countdown, the frame exchange can start earlier because the link switching delay of the non-AP STA 51 can already be used for the CW countdown. While the non-AP STA 51 is transmitting on link 2, the Rx STA 52 can monitor link 1 to avoid or reduce the media synchronization delay timer.

[0052] Since the AP MLD 60 may initiate a downlink data transmission over link 1 that it expects the non-AP STA 51, but not the Rx STA 52, to receive or respond to, the non-AP MLD 51 must immediately notify the AP MLD 60 of the link switch via a link switch notification. This may be accomplished before the actual link switch if the original link is accessible and served by the non-AP STA 51, or after the actual link switch if the original link is not accessible or is observed by the Rx STA 52. In the latter case, the non-AP STA 51 may include the link switch notification as the first data or in the first data sent after the link switch. The link switch notification may indicate the length of the link switch and include a time span after which the link switch is reversed.

[0053] The control information obtained by the Rx STA 52 may also assist in transmitting downlink traffic. Thus, assume that the AP MLD 60 wants to transmit data to the non-AP MLD 50. The Rx STA 52 may perform one or more of the following operations: i. Provide the measured impulse response or transfer function of the channel observed by the Rx STA. This channel state information or beamforming information derived therefrom may then be fed back to the peer MLD via the non-AP STA. The peer STA of the Rx STA can then apply beamforming to the link to the Rx STA. This operation may be applied if the Rx STA is also receiving data. Information c) above may be used for this operation, similar to the information transfer as shown in Figure 15 (dashed arrows). ii. Enhanced Single Radio (EMLSR) controls resources of non-AP STAs. In EMLSR, control frames received from AP MLD indicate which link non-AP STAs should switch or concentrate resources to for data exchange. To receive such frames, EMLSR operation foresees splitting the receiving resources of non-AP STAs, which is not necessary when Rx STAs are present. Figure 19 shows EMLSR operation when Rx STAs are present. Figure 19A shows the initial state before link switching, and Figures 19B and 19C show two options for link switching. As shown in FIG. 19A, one link is observed by non-AP STA51, and the other link is observed by Rx STA52. When Rx STA52 receives an EMLSR control frame (switch request frame), it causes non-AP STA51 to switch its link to the link observed by Rx STA52. Then, Rx STA52 may switch to the link previously observed by non-AP STA51 to obtain link state information to avoid medium synchronization delay when non-AP STA switches back (FIG. 19B), or Rx STA52 may disable its radio (FIG. 19C). This operation may use the information d) described above. Since link switching is different from baseline EMLSR, the switching delay of this operation may also be different. Furthermore, in the setup of FIG. 19, when a switch request frame is sent on link 1, the non-AP STA51 is already tuned to link 1, so the switching delay is zero. For the same reason, a switch request is not actually required on link 1.

[0054] For the AP MLD 60 to recognize the Rx STA 52 or the EMLSR operation with the Rx STA 52, at least the first two phases (discovery and association) shown in FIG. 5 should be performed in the previous setup phase.

[0055] In summary, according to the present disclosure, one or more receiving STAs may be included in the MLD, i.e., one or more STAs that can only receive and not transmit. In contrast to normal STAs, receiving STAs can operate at significantly lower power and are less complex. Receiving STAs can assist the MLD to receive data and / or control information. The present disclosure also describes how links to receive-only STAs can be set up, how response frames such as acknowledgments can be conveyed, and how the Listen Before Talk (LBT) mechanism can be augmented. Furthermore, it is detailed how the control information can be obtained by the receiving STAs and how the control information can be applied in various contexts.

[0056] Thus, the foregoing discussion discloses and describes merely exemplary embodiments of the present disclosure. As will be understood by those skilled in the art, the present disclosure may be embodied in other specific forms without departing from its spirit or essential characteristics. The disclosure of the present disclosure, as well as the remaining claims, are hereby intended to be illustrative and not limiting of the scope of the present disclosure. The present disclosure defines in part the scope of the preceding claim terms, including readily identifiable variations of the teachings herein, such that the inventive subject matter is not dedicated to the public.

[0057] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. An element or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0058] To the extent that embodiments of the present disclosure have been described as being implemented, at least in part, by a software-controlled data processing apparatus, it will be understood that non-transitory machine-readable media bearing such software, such as, for example, optical disks, magnetic disks, semiconductor memories, etc. Moreover, such software may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems.

[0059] The elements of the disclosed devices, apparatus and systems may be implemented by corresponding hardware and / or software elements, such as suitable circuits or circuitry. A circuit is a structural collection of electronic components, including conventional circuit elements, integrated circuits, including application specific integrated circuits, standard integrated circuits, application specific standard products, and field programmable gate arrays. A circuit also includes a central processing unit, a graphics processing unit, and a microprocessor that are programmed or configured according to software code. A circuit includes the above hardware that executes software, but does not include pure software. A circuit or circuitry may be implemented by a single device or unit, or by multiple devices or units, or by chipset(s), or by processor(s).

[0060] Below is a list of further embodiments of the disclosed subject matter. (1) a first multilink device, a first station comprising a transmitter and a receiver and configured to communicate with a first station of a second multilink device over a first link; a second station not comprising a transmitter but comprising a receiver and adapted to receive data from other first stations of the second multilink device on a second link different from the first link; - a circuit configured to control the first station and the second station; Equipped with The second station is configured to provide the received data to the circuit and / or the first station. The first multilink device. (2) A first multilink device as defined in embodiment 1, comprising: configured to collect configuration information from the first station or the second multilink device of the second station; The circuitry is provided by the second multilink device and is configured to configure the second station based on the collected configuration information to collect data from links not used by the first station. The first multilink device. (3) A first multilink device as defined in any one of the preceding embodiments, The first station comprises: - advertising the presence of said second station and its parameters and capabilities to said second multilink device; configured to participate in or establish an agreement with the second multilink device on one or more of an acknowledgment, encryption parameters, and a traffic identifier to link mapping. The first multilink device. (4) The first multilink device defined in embodiment 3, the agreement is valid for the second link to the second station of the first multilink device; and / or The agreement can be the same as that of the first link or can be set separately for the second link. The first multilink device. (5) A first multilink device as defined in any one of the preceding embodiments, The second station propagates reception status information indicating a reception status of one or more second data received from the second multilink device on the second link to the first station; The first station is configured, upon receipt of the reception status information, to transmit a second acknowledgment regarding receipt of the one or more second data to the second multilink device over the first link. The first multilink device. (6) The first multilink device defined in embodiment 5, The first station is configured to, after receiving one or more first data from the second multilink device on the first link, transmit the second acknowledgment together with a first acknowledgment regarding receipt of the one or more first data or combine the first acknowledgment and the second acknowledgment into a single acknowledgment. The first multilink device. (7) The first multilink device defined in embodiment 6, The first station is configured to notify the second multilink device of a reception state propagation delay indicative of a propagation delay of the reception state information from the second station to the first station of the first multilink device. The first multilink device. (8) The first multilink device as defined in any one of the preceding embodiments, further comprising: one or more first stations, each configured to communicate with one or more first stations of other multilink devices and / or other communication devices over different links; one or more second stations, each configured to receive data from one or more first stations of other multilink devices and / or other communication devices on a link different from a link used by one of the first stations of the first multilink device; Equipped with The first multilink device. (9) A first multilink device as defined in any one of the preceding embodiments, The receiver of the second station supports physical layer data in only a legacy modulation and coding format. The first multilink device. (10) A first multilink device as defined in any one of the preceding embodiments, The second station is configured to receive Enhanced Multi-Link Single Radio (EMLSR) control frames from the second multi-link device and to control the link on which the first station needs to switch or concentrate its resources for future frame exchanges with the second multi-link device. The first multilink device. (11) The first multilink device defined in embodiment 3, an EMLSR link switching delay varies depending on whether the EMLSR control frame indicates that the link is the first link or the second link; and / or The EMLSR delay is indicated by the first multilink device to the second multilink device as part of a setup. The first multilink device. (12) A first multilink device as defined in any one of the preceding embodiments, The second station propagates reception status information indicating a reception status of one or more second data received from the second multilink device on the second link to the first station; The first station is configured, upon receipt of the reception status information, to transmit a second acknowledgment regarding receipt of the one or more second data to the second multilink device over the first link. The first multilink device. (13) The first multilink device defined in embodiment 12, The first station is configured to, after receiving one or more first data from the second multilink device on the first link, transmit the second acknowledgment together with a first acknowledgment regarding receipt of the one or more first data or combine the first acknowledgment and the second acknowledgment into a single acknowledgment. The first multilink device. (14) The first multilink device defined in embodiment 13, The first station is configured to notify the second multilink device of a reception state propagation delay indicative of a propagation delay of the reception state information from the second station to the first station of the first multilink device. The first multilink device. (15) The first multilink device as defined in any one of the preceding embodiments, further comprising: one or more first stations, each configured to communicate with one or more first stations of other multilink devices and / or other communication devices over different links; one or more second stations, each configured to receive data from one or more first stations of other multilink devices and / or other communication devices on a link different from a link used by one of the first stations of the first multilink device; Equipped with The first multilink device. (16) A first multilink device as defined in any one of the preceding embodiments, The receiver of the second station supports physical layer data in only legacy modulation and coding formats. The first multilink device. (17) A first multilink device as defined in any one of the preceding embodiments, The first station is configured to communicate with a first station of the second multi-link device and / or a station of a single-link device using a link. The first multilink device. (18) A first multilink device as defined in any one of the preceding embodiments, The first multilink device is configured to operate as a non-access point station (non-AP STA (Access Point STAtion)) or as an access point (AP). (19) A first multilink device as defined in any one of the preceding embodiments, The circuitry may include a control circuit, a Media Access Control (MAC) layer, and / or a Station Management Entity (SME). The first multilink device. (20) A first multilink device as defined in any one of the preceding embodiments, A second station is connected to the first station either via the circuit or directly. The first multilink device. (21) A second multilink device, - two or more first stations, each comprising a transmitter and a receiver and each configured to communicate with a first station or a second station of a first multilink device, one of the first stations communicating with the first station of the first multilink device over a first link and another of the first stations transmitting to a second station of the first multilink device over a second link, the second station of the first multilink device not comprising a transmitter but comprising a receiver; - circuitry configured to control the two or more first stations; Equipped with The second multilink device. (22) A second multilink device as defined in embodiment 21, comprising: before transmitting data on the second link to the second station requesting a response from the first multilink device, - waiting for a response to be received from the first station on the first link and initializing its contention window value with a minimum contention value upon receipt of the response; or - Starts further transmissions and increasing its contention window value It is configured as follows: The second multilink device. (23) A second multilink device as defined in any one of embodiments 21 to 22, The first station is configured to transmit low latency data on the second link to the second station of the first multilink device regardless of the state of the first link. The second multilink device. (24) A second multilink device as defined in any one of embodiments 21 to 23, A first station is configured to transmit one or more data to a second station of the first multilink device that does not require a response or that requires a response expected to be received over the first link. The second multilink device. (25) A second multilink device as defined in any one of embodiments 21 to 24, The first station is configured to assume that the one or more data requests are lost if a response is received that does not include at least one reception status information of the one or more data. The second multilink device. (26) A second multilink device as defined in embodiment 25, comprising: The first station is configured to assume that the one or more data have been lost if, after the transmission of the one or more data has been completed, a response is transmitted by the first station of the first multilink device with a delay longer than a reception state propagation delay indicative of a propagation delay of the reception state information from the second station to the first station of the first multilink device. The second multilink device. (27) A second multilink device as defined in any one of embodiments 21 to 26, A first station communicating with the first station of the first multilink device is configured to extend its transmission by padding the last data transmitted to the first station of the first multilink device or by transmitting one or more further data to the first station of the first multilink device. The second multilink device. (28) The second multilink device defined in embodiment 27, The first station is configured to calculate a length of the extension based on an indicated reception state propagation delay indicative of a propagation delay of the reception state information from the second station to the first station of the first multilink device. The second multilink device. (29) A first multilink method for a first multilink device, comprising: - communicating with a first station of a second multilink device over a first link by a first station having a transmitter and a receiver; receiving data from another first station of the second multilink device on a second link different from the first link by a second station not having a transmitter but having a receiver, - controlling the first station and the second station A first multilink method for a first multilink device. (30) A second multilink method for a second multilink device, comprising: - communicating with a first station or a second station of a first multilink device by two or more first stations each having a transmitter and a receiver, where one of the first stations communicates with the first station of the first multilink device over a first link and another of the first stations transmits to a second station of the first multilink device over a second link, the second station of the first multilink device not having a transmitter but having a receiver; - controlling said two or more first stations; Includes A second multilink method for a second multilink device. (31) A non-transitory computer-readable recording medium storing a computer program product that, when executed by a processor, causes the method according to embodiment 29 or 30 to be performed. (32) A computer program comprising program code means for causing a computer to perform each step of the method according to embodiment 29 or 30, when the computer program is executed on the computer.

[0061] One or more of the following embodiments may be combined with one or more of the above embodiments. (A1) a first multilink device, a first station comprising a transmitter and a receiver and configured to communicate with a first station of a second multilink device over a first link; a second station not comprising a transmitter but comprising a receiver and adapted to receive control information from other first stations of the second multilink device and / or from other communication devices on a second link different from the first link; - a circuit configured to control the first station and the second station; Equipped with The second station is configured to provide the received control information to the circuit and / or the first station. The first multilink device. (A2) A first multilink device as defined in embodiment A1, comprising: The first station is configured to transmit control information received by the second station or pre-processed control information and provide the control information to the first station of the second multilink device and / or other communication devices. The first multilink device. (A3) A first multilink device as defined in any one of the preceding embodiments, The control information includes one or more of the following: link information indicating one or more of a length of the received data, a bandwidth of the received data, a Transmit Opportunity (TXOP) period, a Network Allocation Vector (NAV), a received power, a Basic Service Set (BSS) identifier of the received data, restricted channel information of the received data, and status information indicating a busy or idle state of the second link; - channel state information indicative of an impulse response and / or a transfer function between the second station and the second multilink device and / or other communication devices; and - operational advice information indicative of receipt of control information for configuring or reconfiguring operation of the first multilink device. The first multilink device. (A4) A first multilink device as defined in any one of the preceding embodiments, The second station uses the one or more pieces of control information to: - controlling the first station to be steered to an idle link; - controlling the first station to switch to another link; - controlling the first multilink device to be steered to another link to receive control information from another communication device; and - performing a contention window (CW) countdown for the first station to transmit after the CW countdown; configured to perform one or more of The first multilink device. (A5) A first multilink device as defined in any one of the preceding embodiments, the first station is configured to respect a minimum observation period before transmitting after a link switching operation; The circuitry is configured to control the first station to shorten or ignore the minimum observation period in the presence of control information from a second station that has acquired control information for the link to which the first station has switched. The first multilink device. (A6) A first multilink device as defined in embodiment A4, The first station is configured to switch the link used for the communication with the second multilink device and / or other communication devices, and to transmit a link switching notification to the second multilink device and / or other communication devices, the link switching notification including a link switching timing indicating a time and / or a duration of the link switching operation. The first multilink device. (A7) A first multilink device as defined in any one of the preceding embodiments, A first multilink device as defined in any one of the preceding embodiments, The second station is configured to receive Enhanced Multi-Link Single Radio (EMLSR) control frames from the second multi-link device and to control the link on which the first station needs to switch or concentrate its resources for future frame exchanges with the second multi-link device. The first multilink device. (A8) A first multilink device as defined in embodiment A7, comprising: an EMLSR link switching delay varies depending on whether the EMLSR control frame indicates that the link is the first link or the second link; and / or The EMLSR delay is indicated by the first multilink device to the second multilink device as part of a setup. The first multilink device. (A9) A first multilink device as defined in any one of the preceding embodiments, the first station is configured to collect configuration information from the second multilink device; The circuitry is configured to configure the second station based on the collected configuration information and to receive control information from a link provided by the second multilink device and not used by the first station. The first multilink device. (A10) A first multilink device as defined in any one of the preceding embodiments, The first station comprises: - advertising the presence of said second station and its parameters and capabilities to said second multilink device; Participating in or establishing an agreement with the second multilink device or signaling parameters with the second multilink device regarding one or more of a signal format of control information, encryption parameters, and EMLSR switching delay. It is configured as follows: The first multilink device. (A11) A first multilink device as defined in embodiment 10, the agreement is valid for the second link to the second station of the first multilink device; and / or The agreement can be the same as that of the first link or can be set separately for the second link. The first multilink device. (A12) A first multilink device as defined in any one of the preceding embodiments, The second station obtains the control information from a control frame transmitted in a physical layer data frame that applies only legacy modulation and coding. The first multilink device. (A13) A first multilink device as defined in any one of the preceding embodiments, the control information received by the second station is embedded in physical layer data that is split into a first portion that applies legacy modulation and coding and a second portion that applies advanced modulation and coding; The second station is configured to decode and demodulate only the first portion of the physical layer data to obtain the control information. The first multilink device. (A14) A first multilink device as defined in embodiment A13, The second station is configured to stop receiving the first portion of the physical layer data and to continue receiving when the physical layer data ends. The first multilink device. (A15) A first multilink device as defined in embodiment A14, the time of the stop of reception is dependent on the decoded format of the physical layer data; and / or The time of the reception duration depends on the length indicated in the first portion of the physical layer data. The first multilink device. (A16) A first multilink device as defined in any one of the preceding embodiments, The second station applies legacy modulation and coding configured to support reception of physical layer data and / or modulated and coded according to a modulation and coding scheme of a Basic Rate Set (BSS). The first multilink device. (A17) A first multilink device as defined in any one of the preceding embodiments, The second station is configured to support reception of physical layer data applying a non-High Throughput (non-HT) or non-HT overlapped transmission format. The first multilink device. (A18) A first multilink device as defined in any one of the preceding embodiments, further comprising: one or more first stations, each configured to communicate with one or more first stations of other multilink devices and / or other communication devices over different links; one or more second stations, each configured to receive control information from one or more first stations of other multilink devices and / or other communication devices on a link different from a link used by one of the first stations of the first multilink device; Equipped with The first multilink device. (A19) A first multilink device as defined in any one of the preceding embodiments, The first station is configured to communicate with a first station of the second multi-link device and / or with a station of a single-link device using a link. The first multilink device. (A20) A first multilink device as defined in any one of the preceding embodiments, The first multilink device is configured to operate as a non-access point station (non-AP STA) or an access point (AP). The first multilink device. (A21) A first multilink device as defined in any one of the preceding embodiments, The circuitry may include a control circuit, a Media Access Control (MAC) layer, and / or a Station Management Entity (SME). The first multilink device. (A22) A first multilink device as defined in any one of the preceding embodiments, The second station is connected to the first station either via the circuit or directly. The first multilink device. (A23) A multi-link method for a first multi-link device, comprising: - communicating with a first station of a second multilink device over a first link by a first station having a transmitter and a receiver; receiving control information from other first stations of the second multilink device and / or from other communication devices on a second link different from the first link by a second station not comprising a transmitter but comprising a receiver, - controlling the first station and the second station by a circuit; - providing said received control information to said circuit and / or said first station A multilink method for a first multilink device. (A24) A non-transitory computer-readable recording medium storing a computer program product that, when executed by a processor, causes the method according to embodiment A23 to be performed. (A25) A computer program comprising program code means which, when executed on a computer, causes the computer to carry out each of the steps of the method according to embodiment A23.

Claims

1. A first multilink device, a first station comprising a transmitter and a receiver and adapted to communicate over a first link with a first station of a second multilink device; a second station not comprising a transmitter but comprising a receiver and adapted to receive data from other first stations of the second multilink device on a second link different from the first link; a circuit configured to control said first station and said second station; Equipped with The second station is configured to provide the received data to the circuit and / or the first station. The first MultiLink device.

2. 2. A first multilink device according to claim 1, comprising: configured to collect configuration information from the second multilink device of the first station or the second station; The circuitry is provided by the second multilink device and is configured to configure the second station based on the collected configuration information to collect data from links not used by the first station. The first MultiLink device.

3. 2. A first multilink device according to claim 1, comprising: The first station includes: - advertising the presence of said second station and its parameters and capabilities to said second multilink device; configured to participate in or establish an agreement with the second multilink device on one or more of an acknowledgement, encryption parameters, and a traffic identifier to link mapping; The first MultiLink device.

4. 4. A first multilink device according to claim 3, comprising: the agreement is valid for the second link to the second station of the first multilink device; and / or The agreement can be the same as that of the first link or can be set separately for the second link. The first MultiLink device.

5. 2. A first multilink device according to claim 1, comprising: The second station propagates reception status information indicating a reception status of one or more second data received from the second multilink device on the second link to the first station; The first station is configured, upon receipt of the reception state information, to transmit a second acknowledgment regarding receipt of the one or more second data to the second multilink device over the first link. The first MultiLink device.

6. 6. A first multilink device according to claim 5, comprising: The first station is configured to, after receiving one or more first data from the second multilink device on the first link, transmit the second acknowledgment together with a first acknowledgment regarding receipt of the one or more first data or combine the first acknowledgment and the second acknowledgment into a single acknowledgment. The first MultiLink device.

7. 7. A first multilink device according to claim 6, comprising: The first station is configured to notify the second multilink device of a reception state propagation delay indicative of a propagation delay of the reception state information from the second station to the first station of the first multilink device. The first MultiLink device.

8. 2. A first multilink device as claimed in claim 1, further comprising: one or more first stations, each adapted to communicate with one or more first stations of other multilink devices and / or other communication devices on different links; one or more second stations, each configured to receive data from one or more first stations of other multilink devices and / or other communication devices on a link different from the link used by one of the first stations of the first multilink device; Equipped with The first MultiLink device.

9. 2. A first multilink device according to claim 1, comprising: The receiver of the second station supports physical layer data in only legacy modulation and coding formats. The first MultiLink device.

10. a second multilink device, - two or more first stations, each comprising a transmitter and a receiver and each configured to communicate with a first station or a second station of a first multilink device, one of the first stations communicating with the first station of the first multilink device over a first link and another of the first stations transmitting to a second station of the first multilink device over a second link, the second station of the first multilink device not comprising a transmitter but comprising a receiver; - a circuit configured to control said two or more first stations; Equipped with The second MultiLink device.

11. A second multilink device according to claim 10, comprising: a first station, before transmitting data on the second link to the second station requesting a response from the first multilink device; - waiting for a response to be received from the first station on the first link and initialising its contention window value with a minimum contention value once the response is received; or - Start further transmissions and increase its contention window value It is configured as follows: Second Multilink device.

12. A second multilink device according to claim 10, comprising: The first station is configured to transmit low latency data on the second link to the second station of the first multilink device regardless of the state of the first link. The second MultiLink device.

13. A second multilink device according to claim 10, comprising: A first station is configured to transmit one or more data to a second station of the first multilink device that does not require a response or that requires a response expected to be received over the first link. The second MultiLink device.

14. A second multilink device according to claim 13, comprising: The first station is configured to assume that the one or more data requests are lost if a response is received that does not include at least one reception status information of the one or more data. The second MultiLink device.

15. 15. A second multilink device as claimed in claim 14, comprising: The first station is configured to assume that the one or more data have been lost if, after the transmission of the one or more data has been completed, a response is transmitted by the first station of the first multilink device with a delay longer than a reception state propagation delay indicative of a propagation delay of the reception state information from the second station to the first station of the first multilink device. The second MultiLink device.

16. A second multilink device according to claim 10, comprising: A first station communicating with the first station of the first multilink device is configured to extend its transmission by padding the last data transmitted to the first station of the first multilink device or by transmitting one or more further data to the first station of the first multilink device. The second MultiLink device.

17. 17. A second multilink device as claimed in claim 16, comprising: The first station is configured to calculate a length of the extension based on an indicated reception state propagation delay indicative of a propagation delay of the reception state information from the second station to the first station of the first multilink device. The second MultiLink device.

18. A first multilink method for a first multilink device, comprising: - communicating with a first station of a second multilink device over a first link by a first station comprising a transmitter and a receiver; receiving data from other first stations of the second multilink device on a second link different from the first link by a second station not comprising a transmitter but comprising a receiver, - controlling the first station and the second station A first multilink method for a first multilink device.

19. A second multilink method for a second multilink device, comprising: - communicating with a first station or a second station of a first multilink device by two or more first stations each comprising a transmitter and a receiver, one of the first stations communicating with the first station of the first multilink device over a first link and another of the first stations transmitting to a second station of the first multilink device over a second link, the second station of the first multilink device not comprising a transmitter but comprising a receiver; - controlling said two or more first stations; Includes A second multilink method for a second multilink device.

20. A non-transitory computer readable storage medium storing a computer program product which, when executed by a processor, causes the computer to perform the method of claim 18 or 19.

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