Transmitting and receiving device and method

Abstract

a transmitting device configured to: obtain and / or generate input data units to be transmitted to one or more receiving devices, the input data units including MAC service data units (MSDUs) and / or control data units; generate MAC protocol data units (MPDUs) from the input data units by adding header information to one or more of the input data units, the header information including at least receiver addresses of the one or more input data units; generate one or more aggregated MAC protocol data units (A-MPDUs) from the MPDUs, the A-MPDUs being generated from at least two of the MPDUs, with at least one A-MPDU including an MPDU addressed to a different receiving device identified by a receiver address in a header of each MPDU; generate physical layer protocol data units (PPDUs) from the A-MPDUs; provide a multi-receiver indication in the PPDU and / or the A-MPDU that implicitly or explicitly indicates whether the A-MPDU includes an MPDU addressed to a different receiving device; and transmit the PPDU, such that the PPDU including the at least one A-MPDU is transmitted to the different receiving devices.

Description

[Technical Field]

[0001] The present disclosure relates to a transmitting device, a receiving device, a transmitting method, and a receiving method. [Background technology]

[0002] Growing latency-sensitive applications such as augmented reality (XR) gaming, remote surgery, and smart manufacturing require delivery of data units (also referred to herein as latency-sensitive data units or preemptive data units) within milliseconds. In traditional WLAN operation, medium access control (MAC) protocol data units (MPDUs) are included in an aggregated MPDU (A-MPDU) by a transmitting device (e.g., a transmitting station (STA) or an access point (AP)). All MPDUs within the A-MPDU are addressed to the same receiving device (e.g., a receiver STA). At the physical (PHY) layer, the A-MPDU is embedded in a PHY protocol data unit (PPDU) and transmitted from the transmitting device to the receiving device.

[0003] The "Background" discussion provided herein is intended to generally set forth the context for the present disclosure. The work of the presently named inventors, to the extent that it is described in this Background section, as well as aspects of the present disclosure that would not qualify as prior art at the time of filing, are not admitted expressly or impliedly as prior art to the present disclosure. Summary of the Invention [Means for solving the problem]

[0004] It is an object to provide more flexibility regarding the transmission of latency-sensitive data units and / or to enable faster delivery of such latency-sensitive data units. A further object is to provide a transmitting / receiving device, as well as a corresponding computer program and a non-transitory computer-readable storage medium for implementing the method.

[0005] According to one aspect, - obtaining and / or generating input data units to be transmitted to one or more receiving devices, the input data units including MAC service data units (MSDUs) and / or control data units; - generating MAC Protocol Data Units (MPDUs) from one or more of the input data units by adding header information to the input data units, the header information including at least a receiver address of the one or more input data units; generating one or more Aggregated MAC Protocol Data Units (A-MPDUs) from the MPDUs, the A-MPDUs being generated from at least two of the MPDUs, with at least one A-MPDU including MPDUs addressed to different receiving devices identified by receiver addresses in a header of each MPDU; generating a physical layer protocol data unit (PPDU) from the A-MPDU; providing a multi-receiver indication in the PPDU and / or the A-MPDU that indicates implicitly or explicitly whether the A-MPDU contains MPDUs addressed to different receiving devices; A transmitting device is provided, the transmitting device including a circuit configured to transmit the PPDU, the PPDU including the at least one A-MPDU being transmitted to a different receiving device.

[0006] According to a further aspect, receiving a physical layer protocol data unit (PPDU) from a transmitting device; - deriving a multi-receiver indication from the received PPDU or from aggregated MAC protocol data units (A-MPDUs) contained in the received PPDU, the multi-receiver indication indicating explicitly or implicitly whether the A-MPDUs contained in the received PPDU contain MAC protocol data units (MPDUs) addressed to different receiving devices; deaggregating at least one A-MPDU with a multi-receiver indication that the A-MPDU contains MPDUs addressed to different receiving devices, and extracting the receiver addresses from the headers of the MPDUs; - A receiving device is provided that includes circuitry configured to: - obtain one or more input data units from an MPDU addressed to the receiving device based on the receiver address, the input data units including a MAC service data unit (MSDU) and / or a control data unit.

[0007] According to a further aspect, there is provided a computer program comprising program means for causing a computer to perform the steps of the methods disclosed herein when the computer program is run on a computer, as well as a non-transitory computer readable recording medium having stored therein a computer program product which, when run by a processor, causes a computer to perform the methods disclosed herein.

[0008] Embodiments are defined in the dependent claims. It is to be 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 devices and those defined in the dependent claims and / or disclosed herein.

[0009] One aspect of the present disclosure is to modify WLAN MAC operations to support transmission of A-MPDUs containing MPDUs addressed to different receiving devices (also referred to herein as multi-STA A-MPDUs). This modification allows for the insertion of latency-sensitive / preemptive MPDUs in the ongoing transmission of a PPDU bearing the A-MPDU.

[0010] The foregoing paragraphs have been provided by way of general introduction and are not intended to limit the scope of the claims that 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:

[0011] A more complete appreciation of the present disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings. [Brief explanation of the drawings]

[0012] [Figure 1A] FIG. 1A is a schematic diagram of MAC and PHY operations according to conventional WLAN operations for transmitting an MSDU. [Figure 1B] FIG. 1B is a schematic diagram of MAC and PHY operation according to conventional WLAN operation for transmitting input data units including MSDUs and / or control data units. [Figure 2] 1 is a schematic diagram of a conventional MAC operation illustrating the problem addressed by the present disclosure; [Figure 3] 1 is a schematic diagram of an A-MPDU used in accordance with the present disclosure. [Figure 4] FIG. 2 is a schematic diagram of MAC and PHY operation according to one embodiment of the present disclosure. [Figure 5] FIG. 2 is a diagram of the main MAC processing blocks in the MAC plane architecture of a WLAN STA according to one embodiment of the present disclosure. [Figure 6] 2 is a schematic diagram illustrating one embodiment of the operation of a general transmitter STA according to the present disclosure. [Figure 7] 1 illustrates the structure of a PPDU and a TXOP according to one embodiment of the present disclosure. [Figure 8] FIG. 2 is a schematic diagram illustrating a first embodiment of an acknowledgement policy according to the present disclosure. [Figure 9] FIG. 10 is a schematic diagram illustrating a second embodiment of an acknowledgement policy according to the present disclosure. [Figure 10]FIG. 10 is a schematic diagram illustrating a third embodiment of an acknowledgement policy according to the present disclosure. [Figure 11] FIG. 10 is a schematic diagram illustrating a fourth embodiment of an acknowledgement policy according to the present disclosure. [Figure 12] FIG. 10 is a schematic diagram illustrating a fifth embodiment of an acknowledgement policy according to the present disclosure. [Figure 13] FIG. 10 is a schematic diagram of another embodiment of the present disclosure regarding the insertion of a high priority MPDU in an A-MPDU after a PPDUTXSTART.request. [Figure 14] 1 is a schematic diagram of an embodiment of a preemptive MPDU insertion in a multi-STA A-MPDU according to the present disclosure using fragmentation. [Figure 15A] 1 is a schematic diagram illustrating an embodiment of inserting preemptive MPDUs in a multi-STA A-MPDU according to the present disclosure using padding and / or MSDU aggregation. [Figure 15B] 1 is a schematic diagram illustrating an embodiment of inserting preemptive MPDUs in a multi-STA A-MPDU according to the present disclosure using padding and / or MSDU aggregation. [Figure 16] 1 is a flowchart illustrating one embodiment of a transmission method according to the present disclosure. [Figure 17] 1 is a flow chart illustrating one embodiment of a receiving method according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] Referring now to the drawings, in which like reference numerals indicate the same or corresponding parts throughout the several views, Figures 1A and 1B are schematic diagrams of MAC and PHY operation according to conventional WLAN operation. In a WLAN, the Medium Access Control (MAC) layer initiates transmission of a MAC Protocol Data Unit (MPDU) by sending a PHYTXSTART.request indication to the physical (PHY) layer, as shown in Figures 1A and 1B. This indication includes a parameter list called a TXVECTOR that is used to configure the PHY operation.

[0014] An MPDU contains one or more MAC service data units (MSDUs) (as shown in Figure 1A) and / or control data units (as shown in Figure 1B). MSDUs arrive from higher layers and are placed in different queues in the MAC layer according to their priority. The Enhanced Distributed Channel Access Function (EDCAF) coordinates channel access for transmitting MSDUs from the queues. A single MSDU can be transmitted at a time, or multiple MSDUs can be aggregated to form an aggregated MSDU (A-MSDU). To transmit an MSDU such as that shown in Figure 1A or an input data unit such as that shown in Figure 1B, the MAC layer takes the MSDU and adds a MAC header and a frame check sequence (FCS) to create an MPDU. The MAC header contains signaling information such as the transmitter address, receiver address (RA), duration, and frame control, and the FCS is a sequence used to verify whether the MPDU was received correctly by the receiver.

[0015] An A-MPDU is a concatenation of MPDUs encapsulated in subframes, each of which contains a delimiter (DEL) and an optional padding (PAD) field. The DEL contains the length of the MPDU within the subframe and a signature for identifying each subframe at the receiver, while the PAD is used to verify that the length of each subframe is a multiple of a set number of bits (e.g., 32 bits). A subframe may consist of only a zero-length DEL field, which is used to satisfy the minimum MPDU start interval requirement or for additional padding. When a PHYTXSTART.request indication is sent, the MSDU to be transmitted is already selected, and the total data length (in octets) is indicated via the TXVECTOR. The A-MPDU is transmitted by the PHY layer as a PHY Service Data Unit (PSDU). The PSDU is processed by the PHY and transmitted to the wireless medium as a PHY Protocol Data Unit (PPDU). The PPDU contains a preamble containing training and signaling fields, and a data field in which the PSDU is transmitted.

[0016] When the PHY receives a PHYTXSTART.request, the process of transmitting a PPDU begins with the PHY preamble. The PHY sends a PHYTXSTART.confirm indication to the MAC to indicate it is ready to receive data. The MAC then issues a PHY-Data.request indication to the PHY to transfer one octet of data and transmits that octet. Once the PHY receives the data octet, it issues a PHY-Data.confirm, indicating to the MAC that it is ready to receive the next octet. This process continues until the last octet of the PSDU is sent. Finally, the MAC issues a PHYTXEND.request to indicate to the PHY that the PSDU transmission is complete, and the PHY terminates the PPDU transmission and issues a PHYTXEND.confirm to the MAC.

[0017] In WLAN operation, all MPDUs contained in an A-MPDU are addressed to the same receiver (also referred to herein as receiving device or receiver STA), which limits the flexibility that a transmitter (also referred to herein as transmitting device or transmitter STA) has to deliver data to different STAs (i.e., different receiving devices) with different priority levels.

[0018] An MPDU is often selected when the MAC sends a PHYTXSTART.request to the PHY. If a high-priority MPDU addressing a different STA than the initial A-MPDU is queued after the PHYTXSTART.request and before the last scheduled MPDU is transmitted, it cannot be transmitted according to traditional WLAN behavior.

[0019] In this context, it should be noted that an MPDU can generally carry an MSDU and / or a control data unit (also generally referred to herein as an input data unit) (see FIG. 1B). A control data unit is herein understood as a control and / or management frame such as an acknowledgement, a link measurement, a trigger, a channel reservation indication (RTS / CTS), an association, an authentication, a beacon, etc. According to the present disclosure, input data units (MSDUs and / or control data units) to be transmitted to one or more receiving devices are obtained or generated by a transmitting device. An MPDU is then generated from the input data units by adding header information to one or more of the input data units, which are then aggregated into an A-MPDU. The MAC header of an MSDU may differ from the MAC header of a control data unit, but generally, the MAC header has transmitter and receiver address information. The difference may mainly relate to additional information for the receiver to know how to interpret certain parts of the control data unit.

[0020] 2 is a schematic diagram of conventional MAC operation illustrating the problem addressed by this disclosure, specifically the delay of high-priority data transmission until the next PPDU. When a PHYTXSTART.request is issued by the MAC, a receiver STA1 of an A-MPDU is selected. Subsequently, during the transmission of a PPDU carrying the A-MPDU, a high-priority MSDU addressed to receiver STA2 is queued. Because the current A-MPDU transmission cannot include MPDUs addressed to a different individual STA other than STA1, and the PPDU transmission cannot be stopped, the transmission of the high-priority MSDU for STA2 must be delayed until the next PPDU transmission. This delay may be too high for latency-sensitive applications.

[0021] According to the present disclosure, modifications to MAC operations are made to support the insertion of MPDUs addressed to different receiver STAs within an A-MPDU. Figure 3 is a schematic diagram of an A-MPDU 10 used in accordance with the present disclosure. Here, this A-MPDU 10, which includes the insertion of MPDUs 11, 12 to different receiver STAs (i.e., MPD 11 is addressed to a different receiver STA than MPD 12), is referred to as a multi-STA A-MPDU. One modification to the frame structure of the A-MPDU is to allow different receiver addresses (RAs) in the MAC headers of MPDUs carried in A-MPDU sub-frames of the same A-MPDU.

[0022] This feature can be implemented to allow one or more high-priority MSDUs destined for different STAs to be transmitted in the same A-MPDU. Furthermore, in the context of preemption, it allows a high-priority MSDU to be transmitted in an ongoing PPDU transmission (after a PHYTXSTART.request) if its transmission time permits. This is illustrated in Figure 4, which is a schematic diagram of MAC and PHY operation according to one embodiment of the present disclosure that allows for the insertion of a preemptive MPDU in an A-MPDU 10 during the transmission of a PPDU. This feature allows for timely delivery of latency-sensitive data that would otherwise have to wait for another PPDU transmission, as shown in Figure 2.

[0023] To support the use of multi-STA A-MPDU, a session setup may be performed between the sender and potential receiver STAs. The session setup creates an agreement on an operating mode defined by either:

[0024] a) Case 1, Fixed Receiver STA Agreement: Define at least a primary receiver STA and one or more secondary receiver STAs, identified by MAC address and / or association identifier (AID). The primary STA is the main target receiver of a multi-STA A-MPDU whose first MPDU is addressed to it. Furthermore, the initial frame exchange to establish a transmit opportunity (TXOP) need only be with the primary STA. A secondary receiver STA can receive one or more MPDUs addressed to it in a multi-STA A-MPDU whose first MPDU is addressed to the primary STA.

[0025] b) Case 2, Dynamic Receiver STA Agreement: A set of potential receiver STAs capable of supporting multi-STA A-MPDU operation is defined, with each STA identified by its MAC address and / or AID. From this set, a primary receiver STA is selected when establishing a TXOP. The main roles of the primary and secondary STAs are the same as in Case 1.

[0026] The multi-STA A-MPDU session setup may also be used to exchange capabilities, defined parameters, instructions, and specific functions to be used between the sender STA and potential receiver STAs. Information exchanged in the session setup may include one or more of the following: - a session identifier, - an indication type for identifying a multi-STA A-MPDU; - PPDU type that can be equipped with multi-STA A-MPDU, a time interval during which a multi-STA A-MPDU may be transmitted, including a start time, duration, and / or end time; - Traffic Identifier (TID) and / or Access Category (AC) that can be used to identify the priority of multi-STA A-MPDUs; The minimum MPDU start interval of multi-STA A-MPDU that can be supported by all STAs; - PHY parameters supported by all STAs addressed in a multi-STA A-MPDU session (e.g., bandwidth, NSS, MCS, RU size, guard interval); Acknowledgment policies that can be used for multi-STA A-MPDUs; - Resource unit (RU) pre-allocation used for the transmission of multi-STA A-MPDUs carried by a multi-user (MU) PPDU.

[0027] The following describes the multi-STA A-MPDU operation disclosed herein in more detail. All STAs that are intended receivers of at least one MPDU in the multi-STA A-MPDU must be able to decode the PPDU that contains the multi-STA A-MPDU. Therefore, the following considerations may be taken into account:

[0028] Figure 5 is a diagram of the main MAC processing blocks in the MAC plane architecture of a WLAN STA according to an embodiment of the present disclosure. The left column shows the flow of data units when a transmitter STA is transmitting an MSDU (MSDU flow - transmit 20), and the right column shows the flow of data units when a receiver STA is receiving an MSDU (MSDU flow - receive 30). In the transmitter flow, MSDUs are obtained from upper layers and are optionally aggregated (step 21) or fragmented (step 22) depending on their size to improve data transmission efficiency. The MSDUs are then encrypted (step 23) to provide secure transmission. MPDUs are created by inserting an MPDU header (also called a MAC header) and adding cyclic redundancy check (CRC) bits (step 24). Finally, the MPDUs are aggregated (step 25) and sent to the PHY layer for transmission. In the receiver flow, an A-MPDU or MPDU is received from the PHY layer, and de-aggregation of the A-MPDU (if present) is performed (step 31) to obtain individual MPDUs. For each MPDU, header information is extracted, and a CRC verification (step 32) is performed to check whether the MPDU was received correctly. Receiver Address (RA) filtering (step 33) checks whether the RA in the header information matches the RA of the receiver device. If the addresses match, the receiver device continues processing the MSDU content. This includes a Block Ack scoreboard (step 34) to track received MSDUs, and duplicate detection (step 35) to identify MSDUs received multiple times. Next, the MSDU is decoded (step 36), defragmented (step 37), and de-aggregated (step 38) (if the MPDU contains an A-MSDU). Finally, the MSDU is forwarded to upper layers.

[0029] Figure 6 is a schematic diagram illustrating an embodiment of general transmitter STA operation 40 according to the present disclosure. Figure 7 illustrates the corresponding structure of a PPDU 14 and a TXOP according to an embodiment of the present disclosure. First, a multi-STA A-MPDU session setup with potential receiver STAs is performed (step 41), and a TXOP is created with the primary STA, or the primary and secondary STAs, or all STAs (broadcast) (step 42). A multi-STA A-MPDU should not be created with a receiver STA that does not belong to a previous agreement made in the multi-STA A-MPDU session.

[0030] A multi-STA A-MPDU indication 15 (also called a multi-receiver indication) may be set and used to indicate that the current and / or next PPDU contains a multi-STA A-MPDU (steps 43 and 45). This multi-STA A-MPDU indication can be made in a separate PPDU before the PPDU containing the multi-STA A-MPDU (step 43) or within the PPDU containing the multi-STA A-MPDU (step 45). Furthermore, this indication can be made implicitly or explicitly. An implicit indication can be made by the type of PPDU, and / or the time interval at which the PPDU is transmitted, and / or the A-MPDU with the MAC address of the first MPDU set to the primary STA. The implicit indication should be fixed within the multi-STA A-MPDU session setup.

[0031] At the MAC level, the MAC header can explicitly indicate that the current frame is a multi-STA A-MPDU frame. This indication can be carried in the frame control field. Another explicit indication can be provided in the DEL at the beginning of the A-MPDU and / or in the first A-MPDU subframe addressed to the primary STA to identify the A-MPDU as a multi-STA A-MPDU. This can be done by using a special DEL signature. Another explicit indication can be provided by a PHY-level indication in the PHY preamble of the PPDU to indicate the presence of a multi-STA A-MPDU, particularly to indicate which RU contains the multi-STA A-MPDU. As yet another option, the explicit indication can be provided in a separate frame, which can be the information field portion of a dedicated frame or a frame that directly follows (e.g., after a regulatory interframe space (IFS)) the PPDU containing the multi-STA A-MPDU. This frame can indicate the same information as described above for the other options of the multi-STA A-MPDU indication.

[0032] Thereafter, the first MPDU containing data includes MPDU 11 addressed to the primary receiver STA (step 46). The RA in the MAC header of each MPDU is set to the MAC address of the STA addressed in the MPDU. Additionally, if the PPDU format requires this information (e.g., includes a user information field as part of the MU-PPDU), the AID is set to the AID of the primary STA.

[0033] An indication 16 of MPDUs addressed to secondary receiver STAs (called Secondary STA MPDU indication or simply Secondary MPDU indication), if present, is included (step 47), which can be done by one or more of the following: -Providing a session identifier that can be added to PHY or MAC signaling; - including in the MAC signaling at the start of the A-MPDU a tuple indicating the MAC address of the secondary STA and the MPDU position within the A-MPDU of the addressed MPDU; - using a special DEL preceding and / or within the A-MPDU subframe containing the MPDU addressed to the secondary STA (possible by using a special DEL signature); and - The AID of the secondary STA addressed in the multi-STA A-MPDU transmitted in the corresponding RU, or the group AID for identifying the primary STA and / or secondary STA, is included in the PHY signal (this can be added as part of the user information field).

[0034] Preferably, it must be ensured that the PHY parameters (e.g., MCS, NSS, bandwidth, RU size, guard interval) used to configure the transmission of the PPDU containing the multi-STA A-MPDU are supported by all receiver STAs, and that all capabilities of each receiver STA potentially addressed in the multi-STA A-MPDU are met (e.g., minimum MPDU start interval). Furthermore, it must be ensured that the TID of the MPDU carried by the multi-STA A-MPDU belongs to an AC that has the same priority as or a higher priority than the primary AC. The primary AC corresponds to the Enhanced Distributed Channel Access Function (EDCAF) that has gained channel access.

[0035] The multi-STA A-MPDU may then be transmitted within a TXOP with the TXOP responder set to the primary STA, or the primary and secondary STAs, or all STAs (broadcast) (step 44). In one embodiment, an acknowledgement policy is set (step 48) to support any of the following (acknowledgment operations are described below): immediate acknowledgement for a single receiver STA, immediate acknowledgement for at least two receiver STAs, or delayed acknowledgement or no acknowledgement for all receiver STAs, and the acknowledgement policy is set to no acknowledgement (No Ack) or delayed acknowledgement Block Ack (BA).

[0036] In one embodiment, the operation of a general primary STA (primary receiver) is as follows: The primary STA listens for any A-MPDUs addressed to it, identified by AID and / or MAC address. It listens for TXOPs with TXOP responder set to itself or broadcast, and / or participates in TXOP establishment. MPDUs are searched for in the RUs addressed to the AID and / or matching its own AID, or MPDUs addressed to a MAC address matching its own. It then participates in the multi-STA A-MPDU session setup and identifies itself as the primary receiver STA based on the agreed-upon mode of operation. It should be noted that in this context, the order of steps may be different. For example, another (non-limiting) order could be: 1) join the multi-STA session setup, 2) participate in TXOP creation, 3) listen for A-MPDUs addressed to itself or broadcast, 4) search for MPDUs addressed to itself.

[0037] The RA in the MAC header of a received MPDU that is part of an A-MPDU can be evaluated as follows: If the RA corresponds to its own MAC address, the processing of the MPDU continues after step 33 as shown in Figure 5, i.e. the MPDU content is extracted, decoded and forwarded to higher layers. If the RA does not match its own MAC address, the MPDU content is discarded and the next MPDU is proceeded to. The proceeding behavior is defined by the MPDU length information in DEL. Finally, the acknowledgement policy set for the received MPDU is followed.

[0038] In one embodiment, a typical secondary STA (secondary receiver) operation may be as follows: A secondary STA listens for any A-MPDUs addressed to itself or all STAs, or the primary receiver STA, identified by an AID and / or MAC address configured for the secondary STA, broadcast, or primary STA, respectively. It listens for TXOPs for which the TXOP responder is configured for itself and the primary STA, or broadcast, or the primary STA, and / or participates in TXOP establishment. It searches for MPDUs for RUs addressed to an AID matching itself and / or the primary STA, or MPDUs addressed to a MAC address matching itself and / or the primary STA. It also participates in a multi-STA A-MPDU session setup and identifies itself as a secondary receiver STA based on the agreed-upon mode of operation. As noted above, the order of steps may vary and is not limited to the order described here.

[0039] A secondary STA listens for any A-MPDU identified as a multi-STA A-MPDU provided by the transmitter STA. The RA in the MAC header of a received MPDU that is part of the A-MPDU may be evaluated as follows: If the RA corresponds to its own MAC address, processing of the MPDU continues as shown in Figure 5, i.e., the MPDU content is extracted and decoded. If the RA does not match its own MAC address, the MPDU content is discarded and the STA proceeds to the next MPDU. The proceeding behavior is defined by the MPDU length information contained in the DEL. Finally, an acknowledgment policy can be set for the received MPDU.

[0040] It should be noted that an essential element of this disclosure is that MPDUs within an A-MPDU can be addressed to different receivers. However, it is not necessary to add MPDUs addressed to different receivers in every A-MPDU; in some A-MPDUs, all MPDUs may be addressed to the same receiver. This is the case, for example, in the case of preemption, when there is not enough time in the PPDU to add MPDUs addressed to different receivers. Thus, the multi-STA A-MPDU indication may always be present, either explicitly or implicitly, but actual MPDUs with different receiver addresses may or may not be included in the A-MPDU.

[0041] The following describes a multi-STA acknowledgment operation. The acknowledgment procedure, in which a receiver indicates to a transmitter whether a received data unit has been received correctly or incorrectly, is a fundamental aspect of a WLAN network for providing quality of service. In a WLAN, an acknowledgment can be provided for each transmitted MPDU. In a multi-STA A-MPDU, at least two MPDUs are intended for different STAs. Therefore, the acknowledgment operation is coordinated for all STAs that are receivers of the multi-STA A-MPDU according to an embodiment.

[0042] There are at least four main acknowledgement policies (Ack policies) that can be extended to support multi-STA A-MPDU acknowledgement. 1) No Ack: This means that the receiver STA takes no action regarding acknowledgment when receiving the MPDU, and the sender STA discards the MPDU as soon as it sends it. 2) Normal Ack: A simple acknowledgment frame sent by a receiver STA via a specified IFS after receiving a PPDU carrying an MPDU. This policy does not support A-MPDU acknowledgment because Ack can only provide feedback for the reception of one MPDU. 3) Implicit Block Ack Request (BAR): After receiving a PPDU containing an MPDU that requires acknowledgment, the receiver STA can acknowledge one or more MPDUs in a Block Ack (BA) frame sent individually or as part of an A-MPDU carrying a given IFS. This policy supports A-MPDU acknowledgment. 4) BA: The receiver STA takes no immediate action upon receiving the MPDU other than updating the scoreboard, i.e., recording the status of the acknowledgment. The receiver STA sends a BA at a future point in time after receiving a BAR from the sender STA.

[0043] The Ack policy can be standardized or pre-agreed upon as part of the multi-STA A-MPDU session setup, and only a simple indication to identify the Ack policy can be included in the MPDU. Alternatively, this indication can be<TID,RA> It can also be obtained implicitly from the tuple. The acknowledgment procedure for a multi-STA A-MPDU may be based on the number of receivers that require (or do not require) an immediate response. Next, we will explain the different Ack policies.

[0044] 8 is a schematic diagram illustrating a first embodiment (Case 1) of an Ack policy according to the present disclosure. According to this embodiment, only MPDUs for one receiver STA (e.g., STA2 representing a secondary receiver) require an immediate response, specifically, an acknowledgement immediately upon receipt. Therefore, STA2 must use either the Normal Ack or Implicit BAR policy, while other receiver STAs, e.g., STA1 (representing the primary receiver), must use the BA or No Ack policy. This case may be relevant when STA2 receives high-priority traffic and STA1 receives low-priority traffic, such that the acknowledgement from STA2 is time-critical, but the acknowledgement from STA1 can be sent at a later time.

[0045] If all MPDUs addressed to STA2 have the same Ack status (successfully decoded or not), a Compressed BAck can be sent using the Normal Ack policy. Here, an indication must also be added to identify this frame as a Compressed BAck that covers all acknowledgments for MPDUs sent in the immediately preceding PPDU. If multiple Multi-STA A-MPDUs are sent in a MU-PPDU, only MPDUs addressed to one STA in one Multi-STA A-MPDU can be acknowledged with an immediate acknowledgment.

[0046] According to a further embodiment, the MPDUs of at least two receiver STAs require an immediate response. This case can be further explained based on whether the transmitter supports TF (i.e., whether the STA is an AP). Figure 9 is a schematic diagram illustrating a second embodiment (Case 2a) of an Ack policy according to the present disclosure. According to this embodiment, trigger-based operations are performed when the transmitter is an AP. All MPDUs in a multi-STA A-MPDU that require a response must utilize the BA policy, but MPDUs without an Ack policy may also be included. The AP sends a trigger frame (TF) immediately after the PPDU containing the multi-STA A-MPDU is sent (after the IFS). The TF carries a BA request, and the STAs respond with corresponding acknowledgements and, optionally, data units to the AP in a trigger-based PPDU (TB-PPDU). As shown in Figure 9, the MPDUs sent to STA2 and STA3 require an immediate response, which is sent in the TB-PPDU after the TF sent by the AP. The TB-PPDU in Figure 9 contains two RUs: one for STA2 (top) and one for STA3 (bottom).

[0047] If the PPDU containing the multi-STA A-MPDU contains other MPDUs that do not require an immediate response, the BA can be sent in the same TB-PPDU (different RU) or at a later point after the AP sends the BAR (as shown in Figure 9). According to a variant, the AP includes a Trigger Response Scheduling (TRS) field in the PPDU containing the multi-STA A-MPDU with the BA request appended. The receiver STA responds in the TB-PPDU (after the IFS), as shown in Figure 9.

[0048] According to further embodiments, non-trigger-based operations are implemented, according to which the transmitter STA can be a non-AP. In these cases (Case 2b), we focus on non-trigger-based operations because non-AP STAs cannot send TFs, but the operations herein can also be performed by an AP. A first approach is shown in FIG. 10 , which shows a schematic diagram illustrating a third embodiment of an Ack policy according to the present disclosure, according to which the transmitter STA sets all MPDUs requiring a response to the BA policy and then sequentially sends BARs to the receiver STAs of MPDUs requiring an immediate response. The order in which the BARs are sent can be selected based on the TID. If there are other MPDUs requiring a non-immediate response, the transmitter STA can send a BAR at a later time.

[0049] The second approach is shown in FIG. 11, which shows a schematic diagram illustrating a fourth embodiment of an Ack policy according to the present disclosure, whereby an implicit BAR policy is used for MPDUs requiring an immediate response with an additional indication, shown as Sequential BAR (SBAR) in FIG. 11, indicating to each receiver STA the order in which the acknowledgements should be sent. After the PPDU containing the multi-STA A-MPDU is finished, the receiver STA sends a BAck frame sequentially following a predetermined IFS. Other MPDUs must be set to the BA or No Ack policy. If some MPDUs require a non-immediate response, the transmitter STA can send a BAR at a later point in time.

[0050] In the aforementioned approaches utilizing either BAR or SBAR, a non-immediate BAck may be included in an immediate BAck frame if the receiving STA is the same. In the SBAR approach, when several receiving STAs send BAcks sequentially, it is preferable to keep their BAck transmissions aligned in time to avoid collisions and / or maintain the regulated IFS. According to Figure 11, it is assumed that STA2 and STA3 are within range of each other and that STA3 can detect when its BAck(p1) transmission ends so that it can send the corresponding BAck(p2) frame immediately after the predetermined IFS.

[0051] If STA2 and STA3 are out of range of each other, the transmitter STA can send a short Ack frame after each BAck frame from each receiver STA (except the last one) to maintain time alignment between BAck transmissions. This is shown in Figure 12, which shows a schematic diagram illustrating a fourth embodiment of an Ack policy according to the present disclosure.

[0052] Next, we will discuss a preemption use case of the present disclosure. This refers to when a high-priority MPDU (addressed to a different STA), called a preemptive MPDU, is inserted into an A-MPDU after a PHYTXSTART.request. This is illustrated in FIG. 13, which shows a schematic diagram of another embodiment of the present disclosure regarding the insertion of a high-priority MPDU 12 in an A-MPDU 10 after a PPDUTXSTART.request. In this case, the preemptive MPDU 12 replaces one or more MPDUs 11 to be transmitted (in this case, the last MPDU 11') and is sent in a later PPDU. Therefore, the transmitter STA needs to consider the following:

[0053] The multi-STA A-MPDU length shall not exceed the PSDU length indicated in the PHYTXSTART.request at the start of the PPDU transmission. This can be achieved by one or more of the following: The length of the preemptive MPDU shall be the same as the length of the non-preemptive MPDU it replaces, and / or padding shall fill the PSDU length.

[0054] 14 is a schematic diagram of an embodiment of inserting a preemptive MPDU in a multi-STA A-MPDU using fragmentation according to the present disclosure. In this case, MSDU2 is split into two parts, the first part having enough octets to fill the remainder of the A-MPDU length without exceeding the PSDU length. The second part is transmitted in a later PPDU (not shown).

[0055] FIG. 15 is a schematic diagram of an embodiment of inserting a preemptive MPDU in a multi-STA A-MPDU using padding according to the present disclosure. According to a first embodiment shown in FIG. 15A, a zero-length delimiter (DEL) 16 is used to pad the end of the A-MPDU. This option can be used when the padding length, i.e., the difference between the end of the last A-MPDU subframe and the end of the PSDU, is small or is less than or equal to a predefined margin. According to a second embodiment shown in FIG. 15B, several MSDUs 17 are aggregated into an A-MSDU 18 to create an MPDU that can fill the remaining A-MPDU length. This option can be used when the padding length is large or exceeds the margin. However, the following points must be considered: the RA of the aggregated MSDUs within the A-MSDU should be the same, the MSDU used for padding should have the same or higher priority as the preemptive MSDU, and fragmentation of additional MSDUs is possible to obtain an MPDU length that fills the A-MPDU length.

[0056] The duration field of the preemptive MPDU should be the same as the duration fields of all MPDUs in the A-MPDU, i.e., a consistent indication should be given at the end of the PPDU (the same as all other MPDUs in the A-MPDU) so that other STAs can set their Network Allocation Vectors (NAVs) appropriately.

[0057] To support multi-STA A-MPDU operation with a legacy STA, the legacy STA may be considered as the primary STA, where the following considerations may be taken into account: The behavior of a typical transmitter STA with the primary receiver STA as the legacy STA may be modified as follows: A multi-STA A-MPDU may be transmitted to a primary STA that is a legacy STA without an established multi-STA A-MPDU session. An implicit multi-STA A-MPDU indication shall be used, i.e., the PPDU and A-MPDU formats shall be legacy compatible. Only MPDUs addressed to the primary STA shall be included before MPDUs addressed to secondary STAs. A special DEL or subframe, which is not legacy compatible, shall be inserted after the MPDU addressed to the primary STA is transmitted. The DEL or subframe prevents the primary STA from decoding the remainder of the A-MPDU and indicates to the secondary STA that the following MPDU was addressed to it.

[0058] FIG. 16 shows a flowchart of one embodiment of a transmission method 100 according to the present disclosure, implemented by a transmitting device. In a first step 101, input data units to be transmitted to one or more receiving devices are obtained (e.g., received or obtained from a higher layer) and / or generated. The input data units consist of MSDUs and / or control data units. In a second step 102, MPDUs are generated from the input data units by adding header information to one or more of the input data units. The header information includes receiver addresses of at least one or more of the input data units. In a third step 103, one or more A-MPDUs are generated from the MPDUs. The A-MPDUs are generated from at least two of the MPDUs. At least one A-MPDU includes MPDUs addressed to different receiving devices, identified by the receiver addresses in the headers of each MPDU. In a fourth step 104, PPDUs are generated from the A-MPDUs. In a fifth step 105, a multi-receiver indication is provided implicitly or explicitly in the PPDU and / or A-MPDU, the multi-receiver indication indicating whether the A-MPDU contains MPDUs addressed to different receiving devices. In a sixth step 106, the PPDU is transmitted, with the PPDU containing at least one A-MPDU being transmitted to the different receiving devices.

[0059] FIG. 17 illustrates a flowchart of an embodiment of a receiving method 200 according to the present disclosure, implemented by a receiving device capable of processing multi-STA A-MPDUs.

[0060] In a first step 201, a PPDU is received from a transmitting device. In a second step 202, a multi-receiver indication is derived from the received PPDU or an A-MPDU contained in the received PPDU, which indicates explicitly or implicitly whether the A-MPDU contained in the received PPDU contains MPDUs addressed to different receiving devices. In a third step 203, at least one A-MPDU for which the multi-receiver indication indicates that it contains MPDUs addressed to different receiving devices is de-aggregated, and a receiver address is extracted from the MPDU header. In a fourth step 204, one or more input data units are obtained from the MPDU addressed to the receiving device based on the receiver address, where the input data units consist of MSDUs and / or control data units.

[0061] In summary, according to the present disclosure, modifications are made to WLAN MAC operation to support the transmission of A-MPDUs containing MPDUs with different receiving stations (STAs). This allows for the insertion of preemptive MPDUs into ongoing transmissions of PPDUs containing A-MPDUs. Furthermore, this overcomes the limitations on the flexibility of the transmitter STA in conventional WLAN operation when data must be delivered to different STAs with different levels of priority.

[0062] In summary, according to the present disclosure, link adaptation is proposed in the context of hybrid ARQ soft-combining techniques such as Chase Combining (CC) and / or Incremental Redundancy (IR). To implement the soft-combining of retransmissions and initial transmissions, the coding structure is kept unchanged between each transmission. Thus, a mechanism is presented that ensures the same coding structure even if one or more PHY parameters are changed in the (re)transmission process. More specifically, the length of the data field of the PPDU is selected to always have the same size after the PHY processing operation, regardless of the PHY parameters applied.

[0063] 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. Accordingly, the disclosure of this disclosure, as well as the other claims, are intended to be illustrative, not limiting, of the scope of the disclosure. This disclosure defines in part the scope of the preceding claim terms, so as to prevent the public from releasing subject matter that includes readily discernible variations of the teachings herein.

[0064] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single 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.

[0065] To the extent that embodiments of the present disclosure have been described as being implemented, at least in part, by software-controlled data processing apparatus, it will be understood that non-transitory machine-readable media having such software thereon, such as optical disks, magnetic disks, semiconductor memories, etc., are also considered to represent embodiments of the present disclosure. Moreover, such software may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems.

[0066] The elements of the disclosed devices, apparatus, and systems can be implemented by corresponding hardware and / or software elements, e.g., appropriate circuitry. A circuit is a structural collection of electronic components, including integrated circuits, including conventional circuit elements, application-specific integrated circuits, standard integrated circuits, application-specific standard products, and field-programmable gate arrays. Furthermore, a circuit includes a central processing device, a graphics processing device, or a microprocessor that is programmed or configured according to software code. A circuit includes the hardware described above that executes software, but does not include pure software.

[0067] Below is a list of further embodiments of the disclosed subject matter: 1.- Obtaining and / or generating input data units to be transmitted to one or more receiving devices, the input data units including MAC Service Data Units (MSDUs) and / or control data units; - generating MAC Protocol Data Units (MPDUs) from one or more of the input data units by adding header information to the input data units, the header information including at least a receiver address of the one or more input data units; generating one or more Aggregated MAC Protocol Data Units (A-MPDUs) from the MPDUs, the A-MPDUs being generated from at least two of the MPDUs, with at least one A-MPDU including MPDUs addressed to different receiving devices identified by receiver addresses in the headers of the respective MPDUs; generating a physical layer protocol data unit (PPDU) from the A-MPDU; providing a multi-receiver indication in the PPDU and / or the A-MPDU that indicates implicitly or explicitly whether the A-MPDU contains MPDUs addressed to different receiving devices; a transmitting device including a circuit configured to transmit the PPDU, such that the PPDU including the at least one A-MPDU is transmitted to a different receiving device. 2. A transmitting device as described in embodiment 1, wherein the circuit is configured to include, in the at least one A-MPDU, one or more preemptive secondary MPDUs addressed to a secondary receiving device in addition to one or more primary MPDUs addressed to a primary receiving device, even if the input data units included in the one or more preemptive secondary MPDUs are obtained or generated after the input data units included in the primary MPDUs addressed to the primary receiving device and / or after a request to start transmitting a PPDU. 3. A transmitting device as described in embodiment 2, wherein the circuitry is configured to include PPDU duration information indicating a PPDU duration in the PPDU including the at least one A-MPDU. 4. A transmitting device as described in embodiment 2 or 3, wherein the circuitry is configured to replace one or more primary MPDUs scheduled to be transmitted in the at least one A-MPDU with one or more preemptive secondary MPDUs, and include the replaced one or more primary MPDUs in a PPDU to be subsequently transmitted. 5. The circuit aggregating or fragmenting one or more input data units comprised in a primary MPDU; aggregating one or more input data units comprised in a secondary MPDU; and inserting padding bits into the A-MPDU; 4. The transmitting device of embodiment 3, configured to maintain the PPDU duration indicated by the PPDU duration information in the transmission start request by one or more of: 6. A transmitting device as in any one of the preceding embodiments, wherein the circuitry is configured to include one or more primary MPDUs addressed to a primary receiving device as one or more initial MPDUs in the A-MPDU, and to include one or more secondary MPDUs in the A-MPDU after the one or more initial MPDUs. 7. The transmitting device of embodiment 6, wherein the circuitry is configured to obtain a transmit opportunity (TXOP) with at least a primary receiving device. 8. A transmitting device as in any one of the preceding embodiments, wherein the circuitry is configured to implicitly signal a receiver address as part of a MAC header of each MPDU in the A-MPDU as a multi-receiver indication, the receiver address uniquely identifying a receiving device of the MPDU associated with the MAC header. 9. A transmitting device as described in any one of the preceding embodiments, wherein the circuitry is configured to include in the PPDU including the at least one A-MPDU, and / or in the at least one A-MPDU, and / or in each MPDU of the at least one A-MPDU, a secondary MPDU indication indicating that the PPDU includes one or more MPDUs addressed to a secondary receiving device different from a primary receiving device to which other MPDUs included in the PPDU are addressed, and / or which MPDUs are addressed to the secondary receiving device. 10. The circuit the header and / or signaling fields of said PPDU, an MPDU header of said at least one A-MPDU; a signaling field of said at least one A-MPDU; a delimiter field of a signaling field of said at least one A-MPDU; a header of a first MPDU included in the at least one A-MPDU; and 10. The transmission device of embodiment 9, configured to include the secondary MPDU indication in one or more of a separate indication field or frame. 11. The circuit the header and / or signaling fields of said PPDU, an MPDU header of said at least one A-MPDU; a signaling field of said at least one A-MPDU; a delimiter field of the signaling field of said at least one A-MPDU; a header of a first MPDU included in the at least one A-MPDU; and 10. A transmitting device as in any one of the preceding embodiments, configured to explicitly indicate that the at least one A-MPDU includes MPDUs addressed to different receiving devices by including a multi-receiver indication in one or more of separate indication fields or frames. 12. A transmitting device as in any one of the preceding embodiments, wherein the circuitry is configured to implicitly indicate that the at least one A-MPDU includes an MPDU addressed to a different receiving device by including at least one MPDU addressed to a primary receiver as a first MPDU in the at least one A-MPDU. 13. A transmitting device as in any one of the preceding embodiments, wherein the circuitry is configured to include a receiver address in a header of at least an MPDU addressed to a secondary receiving device different from the primary receiving device, or in a header of all MPDUs. 14. A transmitting device as described in any one of the preceding embodiments, wherein the circuit is configured to set an acknowledgement policy indicating how the receiving device acknowledges receipt of one or more MSDUs included in the MPDU of the at least one A-MPDU, and to include an acknowledgement policy indication indicating the set acknowledgement policy in each header of the MPDU of the at least one A-MPDU. 15. The circuit - if the receiving device immediately acknowledges the MSDU, if only a single receiving device acknowledges at a time, and / or - if the reception of the MSDU is acknowledged in response to an acknowledgement request or is acknowledged without an acknowledgement request, and / or A transmitting device according to embodiment 14, configured to set, as part of a set acknowledgement policy, if reception of an MSDU is not acknowledged at all or is acknowledged with a delay. 16. A transmitting device as in any one of the preceding embodiments, wherein the circuitry is configured to aggregate or fragment one or more primary MSDUs addressed to a primary receiving device, and / or aggregate one or more secondary MSDUs addressed to a secondary receiving device, and / or add padding bits to the A-MPDU. 17. The circuit - to agree on whether multi-receiver operation can be used in which the A-MPDU may contain MPDUs addressed to different receiving devices, and / or - to define a primary receiving device and one or more secondary receiving devices in multi-receiver operation, and / or 10. A transmitting device as in any one of the preceding embodiments, configured to initially perform session setup with one or more receiving devices to exchange capabilities and parameters used in multi-receiver operation. 18. A transmitting device as in any one of the preceding embodiments, wherein the circuitry is configured to use parameters for PHY layer processing based on link quality supported by multiple or all receiving devices to which MPDUs may be addressed in the at least one A-MPDU and / or receiving devices to which MPDUs may be addressed in the at least one A-MPDU. 19.-Receive a physical layer protocol data unit (PPDU) from the transmitting device; - deriving a multi-receiver indication from the received PPDU or from an aggregated MAC protocol data unit (A-MPDU) contained in the received PPDU, the multi-receiver indication indicating explicitly or implicitly whether the A-MPDU contained in the received PPDU contains MAC protocol data units (MPDUs) addressed to different receiving devices; - deaggregating at least one A-MPDU indicating a multi-receiver indication containing MPDUs addressed to different receiving devices and extracting receiver addresses from the headers of the MPDUs; a receiving device including circuitry configured to obtain one or more input data units from an MPDU addressed to the receiving device based on the receiver address, the input data units including MAC service data units (MSDUs) and / or control data units. 20. The circuit - deriving from the PPDU and / or the at least one A-MPDU a secondary MPDU indication that the at least one A-MPDU contains one or more MPDUs addressed to a receiving device different from a primary receiving device to which at least a first MPDU included in the at least one A-MPDU is addressed and / or which MPDUs are addressed to the receiving device; 20. The receiving device of claim 19, configured to retrieve one or more MPDUs addressed to the receiving device based on an indication of the secondary MPDU. 21. The circuit the header and / or signaling fields of said PPDU, an MPDU header of said at least one A-MPDU; a signaling field of said at least one A-MPDU; a delimiter field of the signaling field of said at least one A-MPDU; a header of a first MPDU included in said at least one A-MPDU; a separate instruction field or frame, and 21. The receiving device according to claim 19 or 20, configured to derive a multi-receiver indication and / or said secondary MPDU indication in one or more of the headers of first MPDUs addressed to a primary receiver. 22. A receiving device as described in any one of embodiments 19 to 21, wherein the circuit is configured to derive an acknowledgement policy indication from each MPDU in the at least one A-MPDU in the received PPDU, the acknowledgement policy indicating an acknowledgement policy set by the transmitting device, the acknowledgement policy instructing how the receiving device acknowledges one or more MSDUs included in the MPDU of the at least one A-MPDU, and acknowledge the MSDUs in accordance with the acknowledgement policy. 23. The circuit, based on the indicated acknowledgment policy, - immediately send an acknowledgment of the receipt of the MSDU, and / or - sending an acknowledgement of receipt of the MSDU in response to an acknowledgement request or without an acknowledgement request; and / or 23. A receiving device according to embodiment 22, configured to not transmit or to transmit with a delay an acknowledgement of receipt of an MSDU. 24. The circuit - to agree whether a multi-receive operation can be used in which the A-MPDU may include MPDUs addressed to different receiving devices, and / or - to define the receiving device as a primary receiving device and / or a secondary receiving device in the multi-receive operation; and / or A receiving device described in any one of embodiments 19 to 23, configured to participate in a session setup with a transmitting device to exchange capabilities and parameters used in the multi-receive operation. 25.- Obtaining and / or generating input data units to be transmitted to one or more receiving devices, the input data units including MAC service data units (MSDUs) and / or control data units; - generating MAC Protocol Data Units (MPDUs) from one or more of the input data units by adding header information to the input data units, the header information including at least a receiver address of the one or more input data units; generating one or more Aggregated MAC Protocol Data Units (A-MPDUs) from the MPDUs, the A-MPDUs being generated from at least two of the MPDUs, with at least one A-MPDU including MPDUs addressed to different receiving devices identified by receiver addresses in a header of each MPDU; generating a physical layer protocol data unit (PPDU) from the A-MPDU; - providing, in the PPDU and / or the A-MPDU, an implicit or explicit multi-receiver indication indicating whether the A-MPDU contains MPDUs addressed to different receiving devices; - transmitting the PPDU, and the PPDU including the at least one A-MPDU is transmitted to a different receiving device. 26.-Receive a physical layer protocol data unit (PPDU) from a transmitting device; - deriving a multi-receiver indication from the received PPDU or from an aggregated MAC protocol data unit (A-MPDU) contained in the received PPDU, the multi-receiver indication indicating explicitly or implicitly whether the A-MPDU contained in the received PPDU contains MAC protocol data units (MPDUs) addressed to different receiving devices; - deaggregating at least one A-MPDU indicating a multi-receiver indication containing MPDUs addressed to different receiving devices and extracting receiver addresses from the headers of the MPDUs; - based on the receiver address, obtain one or more input data units from an MPDU addressed to the receiving device, the input data units including a MAC service data unit (MSDU) and / or a control data unit. 27. A non-transitory computer-readable recording medium having stored therein a computer program product that, when executed by a processor, causes the method of embodiment 25 or 26 to be performed. 28. A computer program comprising program code means for causing a computer to carry out the steps of the method according to embodiment 25 or 26, when the computer program is run on a computer.

Claims

1. - obtaining and / or generating input data units to be transmitted to one or more receiving devices, said input data units comprising MAC service data units (MSDUs) and / or control data units; generating MAC Protocol Data Units (MPDUs) from one or more of the input data units by adding header information to the one or more input data units, the header information including at least a receiver address of the one or more input data units; generating one or more aggregated MAC protocol data units (A-MPDUs) from the MPDUs, the A-MPDUs being generated from at least two of the MPDUs, with at least one A-MPDU including MPDUs addressed to different receiving devices identified by receiver addresses in the headers of each MPDU; - generating a physical layer protocol data unit (PPDU) from said A-MPDU; providing a multi-receiver indication in the PPDU and / or the A-MPDU that indicates implicitly or explicitly whether the A-MPDU contains MPDUs addressed to different receiving devices; a transmitting device including a circuit configured to transmit the PPDU, such that the PPDU including the at least one A-MPDU is transmitted to a different receiving device;

2. 2. The transmitting device of claim 1, wherein the circuitry is configured to include, in the at least one A-MPDU, one or more preemptive secondary MPDUs addressed to a secondary receiving device in addition to one or more primary MPDUs addressed to a primary receiving device, even if the input data units included in the one or more preemptive secondary MPDUs are obtained or generated after the input data units included in the primary MPDUs addressed to the primary receiving device and / or after a request to start transmitting a PPDU.

3. 3. The transmitting device of claim 2, wherein the circuitry is configured to replace one or more primary MPDUs scheduled to be transmitted in the at least one A-MPDU with one or more preemptive secondary MPDUs and include the replaced one or more primary MPDUs in a subsequently transmitted PPDU.

4. The circuitry includes PPDU duration information in the PPDU that includes the at least one A-MPDU, the PPDU duration indicating a PPDU duration; and / or - aggregating or fragmenting one or more input data units contained in a primary MPDU; aggregating one or more input data units included in a secondary MPDU; and Inserting padding bits into the A-MPDU.

2. The transmitting device of claim 1, configured to maintain the PPDU duration indicated by the PPDU duration information in the transmission start request by one or more of:

5. 2. The transmitting device of claim 1, wherein the circuit is configured to include one or more primary MPDUs addressed to a primary receiving device as one or more initial MPDUs in the A-MPDU, and to include one or more secondary MPDUs in the A-MPDU after the one or more initial MPDUs.

6. The transmitting device of claim 5 , wherein the circuitry is configured to obtain a transmit opportunity (TXOP) with at least a primary receiving device.

7. 2. The transmitting device of claim 1, wherein the circuitry is configured to implicitly signal a receiver address as part of a MAC header of each MPDU within an A-MPDU as a multi-receiver indication, the receiver address uniquely identifying a receiving device of the MPDU associated with the MAC header.

8. The circuitry includes in the PPDU including the at least one A-MPDU, and / or in the at least one A-MPDU, and / or in each MPDU of the at least one A-MPDU, a secondary MPDU indication indicating that the PPDU includes one or more MPDUs addressed to a secondary receiving device different from a primary receiving device to which other MPDUs included in the PPDU are addressed, and / or which MPDUs are addressed to the secondary receiving device, in particular - the header and / or signaling fields of said PPDU, an MPDU header of said at least one A-MPDU; a signaling field of said at least one A-MPDU; a delimiter field of the signaling field of said at least one A-MPDU; a header of a first MPDU included in said at least one A-MPDU, and 2. The transmission device of claim 1, configured to include the secondary MPDU indication in one or more of a separate indication field or frame.

9. The circuit comprises: - the header and / or signaling fields of said PPDU, an MPDU header of said at least one A-MPDU; a signaling field of said at least one A-MPDU; a delimiter field of the signaling field of said at least one A-MPDU; a header of a first MPDU included in said at least one A-MPDU, and - A transmitting device as described in claim 1, configured to explicitly indicate that the at least one A-MPDU includes MPDUs addressed to different receiving devices by including a multi-receiver indication in one or more of a separate indication field or frame.

10. 2. The transmitting device of claim 1, wherein the circuitry is configured to implicitly indicate that the at least one A-MPDU includes MPDUs addressed to a different receiving device by including at least one MPDU addressed to a primary receiver as a first MPDU in the at least one A-MPDU.

11. The circuit is configured to set an acknowledgement policy indicating how the receiving device acknowledges reception of one or more MSDUs included in an MPDU of the at least one A-MPDU, and to include an acknowledgement policy indication indicating the set acknowledgement policy in each header of the MPDU of the at least one A-MPDU, particularly: - if the receiving device immediately acknowledges the MSDU, only a single receiving device acknowledges at a time, and / or if the reception of the MSDU is acknowledged in response to an acknowledgement request or is acknowledged without an acknowledgement request, and / or A transmitting device according to claim 1, configured to configure, as part of a configured acknowledgement policy, if reception of an MSDU is not acknowledged at all or is acknowledged with a delay.

12. 2. The transmitting device of claim 1, wherein the circuitry is configured to aggregate or fragment one or more primary MSDUs addressed to a primary receiving device, and / or aggregate one or more secondary MSDUs addressed to a secondary receiving device, and / or add padding bits to the A-MPDU.

13. The circuit comprises: - To agree whether multi-receiver operation can be used where an A-MPDU may contain MPDUs addressed to different receiving devices, and / or to define a primary receiving device and one or more secondary receiving devices in multi-receiver operation, and / or A transmitting device according to claim 1, configured to initially perform a session setup with one or more receiving devices to exchange capabilities and parameters used in multi-receiver operation.

14. 2. The transmitting device of claim 1, wherein the circuitry is configured to use parameters for PHY layer processing based on link quality of receiving devices that are supported by multiple or all receiving devices to which MPDUs may be addressed in the at least one A-MPDU and / or that may be addressed by the at least one A-MPDU.

15. - receiving a physical layer protocol data unit (PPDU) from a transmitting device; deriving a multi-receiver indication from a received PPDU or an aggregated MAC protocol data unit (A-MPDU) contained in the received PPDU, the multi-receiver indication indicating explicitly or implicitly whether the A-MPDU contained in the received PPDU contains MAC protocol data units (MPDUs) addressed to different receiving devices; - deaggregating at least one A-MPDU indicating a multi-receiver indication containing MPDUs addressed to different receiving devices and extracting the receiver addresses from the MPDU headers; - A receiving device including circuitry configured to obtain one or more input data units from an MPDU addressed to the receiving device based on said receiver address, said input data units including MAC service data units (MSDUs) and / or control data units.

16. The circuit comprises: - deriving from the PPDU and / or the at least one A-MPDU a secondary MPDU indication indicating that the at least one A-MPDU includes one or more MPDUs addressed to a receiving device different from the primary receiving device to which at least a first MPDU included in the at least one A-MPDU is addressed and / or which MPDUs are addressed to a receiving device; A receiving device according to claim 15, configured to retrieve one or more MPDUs addressed to said receiving device based on an indication of said secondary MPDU.

17. The circuit comprises: - To agree whether a multi-receive operation can be used in which an A-MPDU may contain MPDUs addressed to different receiving devices, and / or - to define the receiving device as a primary receiving device and / or a secondary receiving device in the multi-receive operation, and / or A receiving device according to claim 15, configured to participate in a session setup with a transmitting device in order to exchange capabilities and parameters used in the multi-receive operation.

18. - obtaining and / or generating input data units to be transmitted to one or more receiving devices, said input data units comprising MAC service data units (MSDUs) and / or control data units; generating MAC Protocol Data Units (MPDUs) from one or more of the input data units by adding header information to the one or more input data units, the header information including at least a receiver address of the one or more input data units; generating one or more Aggregated MAC Protocol Data Units (A-MPDUs) from the MPDUs, the A-MPDUs being generated from at least two of the MPDUs, with at least one A-MPDU including MPDUs addressed to different receiving devices identified by receiver addresses in the headers of each MPDU; - generating a physical layer protocol data unit (PPDU) from said A-MPDU; - providing, implicitly or explicitly, in the PPDU and / or the A-MPDU, a multi-receiver indication indicating whether the A-MPDU contains MPDUs addressed to different receiving devices; - transmitting the PPDU, wherein the PPDU including the at least one A-MPDU is transmitted to a different receiving device.

19. - receiving a physical layer protocol data unit (PPDU) from a transmitting device; deriving a multi-receiver indication from a received PPDU or an aggregated MAC protocol data unit (A-MPDU) contained in the received PPDU, the multi-receiver indication indicating explicitly or implicitly whether the A-MPDU contained in the received PPDU contains MAC protocol data units (MPDUs) addressed to different receiving devices; - deaggregating at least one A-MPDU indicating a multi-receiver indication containing MPDUs addressed to different receiving devices and extracting the receiver addresses from the headers of said MPDUs; - deriving one or more input data units from an MPDU addressed to the receiving device based on the receiver address, the input data units comprising MAC service data units (MSDUs) and / or control data units.

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

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