Long packets and quick acknowledgments on the secondary link

Abstract

A wireless communication protocol that operates on a multilink device (MLD) with simultaneous transmit / receive (STR) link pairs and allows an originator to transmit a long MU PPDU on the first link and a receiver to acknowledge (Ack) on the second link. The Ack on the second link can reside on a single resource unit (RU) that can be shared by multiple stations. The Ack can be received during an MP PPDU on the first link, which is a quick Ack. In many cases, this allows the originator to perform a retransmission within the same PPDU, which benefits latency-sensitive real-time traffic in particular.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 265,712, filed December 20, 2021, which is incorporated herein by reference in its entirety.

[0002] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable

[0003] Notification of copyrighted material

[0003] Portions of the material in this patent document may be subject to copyright protection under the copyright laws of the United States and other countries. The copyright owner has no objection to the facsimile reproduction by any third party of the patent document or the patent disclosure as it appears in the U.S. Patent and Trademark Office public files or records, but otherwise reserves all copyright rights. The copyright owner does not hereby waive any rights to have this patent document maintained in confidence, including, but not limited to, the right pursuant to 37 CFR § 1.14.

[0004]

[0005] The techniques of this disclosure relate generally to wireless network communications under CSMA / CA and EDCA, and more particularly to providing quick acknowledgment for long packet traffic. [Background technology]

[0005]

[0007] In current 802.11 protocols, an Ack / BA immediately follows a PPDU on the same link and is used by the CSMA / CA protocol to detect collisions in addition to acknowledging the reception status of each MPDU in the PPDU. To increase efficiency, a PPDU can contain data from multiple users, and data for each user can have multiple priorities. Multiplexing different users and priorities increases efficiency, but can sometimes create overly long PPDUs, which can increase latency.

[0006]

[0008] In the case of a low-latency MPDU within a long PPDU, if the receiver indicates failure to receive the low-latency MPDU after the end of the long PPDU, the duration of the PPDU may be too long for the transmitter to perform a retransmission. The term "long" in this case refers to the delay requirements of the latency-sensitive traffic. Such a retransmission after a long PPDU may violate the delay bounds of the latency-sensitive traffic. Summary of the Invention [Problem to be solved by the invention]

[0007]

[0009] Therefore, there is a need for a protocol that can handle RTA traffic with reduced latency while utilizing secondary links. The present disclosure fulfills this need and provides further advantages. [Means for solving the problem]

[0008]

[0010] A wireless communication in an IEEE 802.11 network is described that can provide rapid acknowledgments as well as faster retransmissions. This description is primarily targeted at the use of Multilink Devices (MLDs) that have simultaneous transmit / receive (STR) capabilities and operate on the network using Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) where Enhanced Distributed Channel Access (EDCA) is utilized for random channel access on all links.

[0009]

[0011] The described protocol provides for an originating MLD to transmit a physical layer protocol data unit (PPDU) (e.g., a long PPDU) containing one or more aggregated MAC protocol data units (AMPDUs) on a first link, and to receive an acknowledgement (Ack) frame as a quick Ack from a receiving MLD on a second link before the originating MLD has completed transmission of the PPDU on the first link.

[0010]

[0012] This is particularly beneficial for latency-sensitive MPDUs (such as those associated with Real Time Application (RTA) traffic) that can be transmitted early in the PPDU and acknowledged (Ack) after reception of the latency-sensitive portion while the remainder of the PPDU is still being transmitted.

[0011]

[0013] The disclosed techniques also allow for reduced latency since retransmissions can be performed on either the first and / or second link within the same long PPDU.

[0012]

[0014] This disclosure provides numerous options / modes / configurations for controlling how these Quick Acks and retransmissions are performed.

[0013]

[0015] Further aspects of the technology described herein will become apparent in the following portions of this specification, and this detailed description is provided for complete disclosure of preferred embodiments of the technology without limiting them.

[0014]

[0016] The techniques described herein will be better understood with reference to the following drawings, which are for illustrative purposes only. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a block diagram of station (STA) hardware in accordance with at least one embodiment of the present disclosure. [Diagram 2]FIG. 1 is a block diagram of a multi-link device (MLD) hardware in accordance with at least one embodiment of the present disclosure. [Diagram 3] A communication diagram of a PPDU illustrating the use of Quick Ack timing or Quick Ack link timing in long packet communication in accordance with at least one embodiment of the present disclosure. [Figure 4] FIG. 1 is a data field diagram using a reserved bit in an MPDU delimiter (non-OMG) to indicate the next Quick Ack opportunity, in accordance with at least one embodiment of the present disclosure. [Diagram 5] 1 is a communication diagram of an initial AMPDU for link 1, not including a quick Ack. [Figure 6] FIG. 1 is a communication diagram of EDCA explicit acknowledgement on L2 and retransmission on L1 in accordance with at least one embodiment of the present disclosure. [Figure 7] FIG. 2 is a communication sequence diagram of multiple Ack attempts during a delayed Block Ack between an originating STA and a receiving STA, in accordance with at least one embodiment of the present disclosure. [Figure 8] FIG. 1 is a communication diagram of implicit confirmation and retransmission in accordance with at least one embodiment of the present disclosure. [Figure 9] FIG. 1 is a communication diagram of a downlink (DL) retransmission on an alternate link in accordance with at least one embodiment of the present disclosure. [Figure 10] FIG. 1 is a communication diagram of Quick Ack timing for uplink (UL) data in accordance with at least one embodiment of the present disclosure. [Figure 11] FIG. 1 is a communication diagram of a shared Ack resource unit (RU) in accordance with at least one embodiment of the present disclosure. [Figure 12] 11 is a communication diagram of a second shared Ack RU in accordance with at least one embodiment of the present disclosure. [Figure 13] FIG. 1 is a communication diagram of a UL zone for increasing access opportunities in accordance with at least one embodiment of the present disclosure. [Figure 14]FIG. 1 illustrates a communication diagram of a UL heavy L1 + DL heavy L2 (UL heavy L1 + DL heavy L2) in accordance with at least one embodiment of the present disclosure. [Figure 15] FIG. 1 is a communication diagram in which an AP uses a trigger frame (TF) on L2 to schedule a transmission start time and / or end time on a Shared Ack RU, in accordance with at least one embodiment of the present disclosure. [Figure 16] FIG. 1 is a flow diagram of receiver processing of a long PPDU that requires an Ack in accordance with at least one embodiment of the present disclosure. [Figure 17] FIG. 1 is a flow diagram of receiver processing of a long PPDU that requires an Ack in accordance with at least one embodiment of the present disclosure. [Figure 18] FIG. 1 is a flow diagram of origination processing of a long PPDU that requires an Ack in accordance with at least one embodiment of the present disclosure. [Figure 19] FIG. 1 is a flow diagram of origination processing of a long PPDU that requires an Ack in accordance with at least one embodiment of the present disclosure. [Figure 20] FIG. 2 is a data field diagram of a Quick Ack configuration field in accordance with at least one embodiment of the present disclosure. [Figure 21] FIG. 2 is a data field diagram of a Special Symbol configuration field in accordance with at least one embodiment of the present disclosure. [Figure 22] FIG. 2 is a data field diagram of a Quick Ack configuration in accordance with at least one embodiment of the present disclosure. [Figure 23] FIG. 11 is a data field diagram of a Shared Ack component in accordance with at least one embodiment of the present disclosure. [Figure 24] 1A-1C are data field diagrams of different example Shared Ack RU elements in accordance with at least one embodiment of the present disclosure. [Diagram 25] FIG. 13 is a data field diagram of a trigger frame having additional subfields in a user information list for use in quick retransmission assignments in accordance with at least one embodiment of the present disclosure. [Figure 26]FIG. 1 is a data field diagram of a BA control field including quick retransmission MCS and Nss subfields in previously reserved bits in accordance with at least one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] 1. Motivations and Assumptions

[0042] The state of the art in this field is described in IEEE P802.11be™ / D2.3 (November 2022) and IEEE P802.11?REVme™ / D2.0 (October 2022).

[0017]

[0043] A station (STA) with real-time application (RTA) data may transmit a PPDU containing only short RTA data and solicit immediate acknowledgment to minimize delay in case of retransmission. However, for various reasons, an access point (AP) or a non-AP station (STA) may decide not to transmit a PPDU containing only RTA data, considering system efficiency or other access rules. For example, to take advantage of downlink (DL) multi-user (MU) multiple input multiple output (MIMO) (by transmitting data to multiple users in the same PPDU using otherwise unused antennas / precoding vectors), an AP may transmit an MU PPDU such that the PSDU of an RTA user is padded to be the same size as the PSDU length of other users. As another example, the PPDU is a UL trigger-based PPDU (TB-PPDU), and the length of the PPDU is determined by the AP. When a STA includes RTA data in a PSDU, the scheduled PPDU duration does not change and other data or padding must be included to meet the PSDU length required for the TB-PPDU. In such a situation where a STA or AP transmits a relatively long PPDU including short RTA data, the station (STA) or AP with real-time application (RTA) data may request a quick acknowledgement (Ack) so that a retry can be performed before the MSDU expires and before the ongoing PPDU is terminated, for example, when there is a second link to perform the acknowledgement (Ack).

[0018]

[0044] The transmitter can transmit short PPDUs on the same link and receive a block acknowledgement (BA) quickly, but in this case, the transmitter sacrifices the efficiency of multi-user (MU) transmission since it cannot multiplex data with other users in the spatial and / or frequency domains.

[0019]

[0045] There is an opportunity to use a long PPDU on the first link and an Ack on the second link. The long MU PPDU that has acquired the channel, despite being in a low priority Access Class (AC), may contain significant levels of padding that can be utilized to provide access to other users' higher priority traffic, such as for use in retransmissions.

[0020]

[0046] Since it takes less than 16 µs to construct a long AMPDU in response to a trigger frame (TF), it is possible that a later arriving RTA MPDU (after TXOP start) can be inserted into an ongoing AMPDU (to the same receiver) rather than having it be aborted by a lower priority AC.

[0021]

[0047] If the transmitter receives a Block Acknowledgement (BA) before the entire AMPDU is completely received, this allows for retransmissions and other retransmission options on the same AMPDU.

[0022]

[0048] In these discussions, a multi-link device (MLD) in this disclosure is considered to provide simultaneous transmission and reception (STR) on the considered link. An MLD that transmits a data MPDU to be acknowledged (Ack) is referred to as an "originating" MLD, whereas an MLD that transmits an Ack in response to receiving the data MPDU is referred to herein as a "receiving" MLD. A traffic identifier (TID) is utilized to identify real-time application (RTA) traffic; traffic identified with an RTA TID does not carry non-RTA traffic.

[0023] 2. Embodiment 2.1. Communication Station (STA and MLD) Hardware

[0051] 1 shows an example embodiment 10 of STA hardware configured to execute the protocol of the present disclosure. An external I / O connection 14 is preferably coupled to an internal bus 16 of the circuitry 12 on which a CPU 18 and a memory (e.g., RAM) 20 are connected to execute a program(s) implementing the communication protocol. The host machine contains at least one modem 22 to support communications, which is coupled to at least one RF module 24, 28, each of which is connected to one or more antennas 29, 26a, 26b, 26c, ..., 26n. RF modules that include multiple antennas (e.g., antenna arrays) allow beamforming to be performed during transmission and reception. In this manner, the STA can transmit signals using a set of multiple beam patterns.

[0024]

[0052] The bus 14 allows connecting various devices to the CPU, e.g., sensors, actuators, etc. On the processor 18, instructions are executed from the memory 20 for executing programs implementing a communication protocol, which allows the STA to perform the functions of an Access Point (AP) station or a normal station (non-AP STA). It is also understood that the programming is configured to operate in different modes (TXOP owner, TXOP sharing participant, source, intermediate, destination, first AP, other AP, station associated with first AP, station associated with other AP, coordinator, coordinatee, AP in OBSS, STA in OBSS, etc.) depending on what role it is performing in the current communication context.

[0025]

[0053] Thus, the illustrated STA HW is configured to include at least one modem and associated RF circuitry to provide communication in at least one band. It should be understood that the present disclosure may be configured to include multiple modems 22, each coupled to any number of RF circuits. In general, the more RF circuits used, the greater the coverage of the antenna beam direction. It should be understood that the number of RF circuits and antennas utilized is determined by the hardware constraints of a particular device. Some RF circuits and antennas may be disabled when the STA determines that it does not need to communicate with neighboring STAs. In at least one embodiment, the RF circuitry is connected to multiple antennas, including frequency converters and array antenna controllers, that are controlled to perform beamforming for transmission and reception. In this manner, the STA may transmit signals using a set of multiple beam patterns, with each beam pattern direction being considered an antenna sector.

[0026]

[0054] It should further be understood that multiple instances of station hardware such as that shown in this figure may be combined into a multi-link device (MLD), which typically has a processor and memory for coordinating activity, but may share these resources since a separate CPU and memory is not always required for each STA in the MLD.

[0027]

[0055] FIG. 2 shows an example embodiment 40 of a multi-link device (MLD) hardware configuration. A Soft-AP MLD is an MLD consisting of one or more associated STAs operating as APs. A Soft-AP MLD should support multiple radio operation at 2.4 GHz, 5 GHz, and 6 GHz. Among the multiple radios, the basic link set is a link pair that satisfies simultaneous transmit / receive (STR) mode, e.g., basic link set (2.4 GHz and 5 GHz), basic link set (2.4 GHz and 6 GHz).

[0028]

[0056] A number of STAs are associated with the MLD, each of which operates on a different frequency link. The MLD has external I / O access to applications that connect to an MLD management entity 48 having a CPU 62 and memory (e.g., RAM) 64 to run programs that implement communication protocols at the MLD level. The MLD distributes tasks to each of the associated stations (here illustrated as STA 1 42, STA 2 44, ..., STA N 46) to which the MLD is connected, and can collect information from each associated station and share the information among the associated STAs.

[0029]

[0057] In at least one embodiment, each STA of the MLD has its own CPU 50 and memory (RAM) 52, which are coupled through a bus 58 to at least one modem 54, which is connected to at least one RF circuit 56, which has one or more antennas. In this example, the RF circuit has multiple antennas 60a, 60b, 60c, ..., 60n, e.g., an antenna array. The modem cooperates with the RF circuit and associated antennas to transmit / receive data frames to / from neighboring STAs. In at least one implementation, the RF module includes a frequency converter, an array antenna controller, and other circuitry for interfacing with the antennas.

[0030]

[0058] It should be understood that each STA in an MLD does not necessarily require its own processor and memory, as they may share resources with each other and / or with an MLD management entity, depending on the particular MLD implementation. It should be understood that the above MLD illustration is provided by way of example and not limitation, but the present disclosure can work with a wide range of MLD implementations.

[0031] 3. Use of long packets and quick ACKs on the secondary link 3.1. ACK timing / ACK link indication for long packets

[0061] 3 illustrates an example embodiment 90 for conveying Ack timing or Ack link in long packet communication. The figure shows a long packet including a preamble followed by a region of special symbols, exemplified as a service field and payload information or a Block Ack Request (BAR) for a quick Ack (advanced BAR) or a check such as a Cyclic Redundancy Check (CRC).

[0032]

[0062] In the following, payload information or advanced BARs that can be conveyed to the receiver, such as in a long packet, are described: (a) One or more time indicators (e.g., symbol number) to the receiver indicating when an Ack can be performed on another link before the completion of the PPDU. For example, the indicated symbol can be the last symbol carrying an RTA MPDU. (b) A suggested or not suggested link ID for the Ack can also be provided, for example, to recommend transmission or not transmission on a link that is currently clear channel assessment (CCA) busy at the originator and should not be the suggested link for sending the Ack. (c) The payload information can be the MCS / Nss of the retransmitted MPDU. (d) The payload can incorporate the TID that needs to be reported in the quick Ack, the number of octets of the TID (including delimiters) before the requested Ack time. The above information does not need to be explicitly indicated in the packet, but can also be pre-configured, as represented by a pre-configured identifier. As an alternative to FIG. 3, the above information can be implicitly indicated in the preamble of the long PPDU by signaling a pre-configured identification using the preamble field. As another alternative, pre-configuration can be signaled using an ADD Block Ack (ADDBA) request and response exchange.

[0033]

[0063] As shown in FIG. 3, the above information may be provided in symbols following the preamble, indicated as special symbols, as in the following example: (a) Part of the above information is carried in a part of the bits of the service field (e.g., the remaining 5 bits of the service field before scrambling), and the remaining information bits are carried in the remaining part of the special symbol. (b) The special symbol may have a pre-configured lower MCS including a single spatial stream (SS). For example, using a lower modulation coding scheme (MCS) provides better protection for the above information than using the following MPDU. Currently, there is no cyclic redundancy check (CRC) for the SERVICE, so a CRC may be added to the next bits used to indicate the SERVICE and the above information. The SERVICE and the above information may be included in a low density parity check (LDPC) codeword (CW) with a different CW length than the rest of the PPDU. The number of special symbols, or the MCS and CW configuration of the special symbols may be indicated in the preamble or may be pre-configured. When a single spatial stream (SS) is used to transmit the special symbols, the channel can be the sum of the multi-stream channels estimated based on the multi-stream training fields in the very high throughput (EHT) preamble from all SSs.

[0034] 3.2. Indicating the presence of an RTA MPDU in an ongoing AMPDU

[0065] In the previous section, it was explained that the sender knows that there is no RTA MPDU in the AMPDU before transmission, and therefore it is assumed that there is no need to send a quick ack if all MPDUs are latency tolerant. Therefore, it may be necessary to inform the receiver of the presence of an RTA MPDU inserted in an ongoing AMPDU. For example, the receiver may not know that there is an RTA MPDU in the AMPDU because the received RTA MPDU has an error.

[0035]

[0066] This can be addressed in a number of ways: (a) A special Short Training Field (STF) can be received to indicate the start and end of the inserted RTA MPDU / symbol. (b) A field within the MPDU delimiter can indicate the presence of an inserted RTA MPDU before the delimiter. In either case (a) or (b), the timing and / or periodicity and / or channel of the Quick Ack can be pre-configured. By detecting (a) or (b), the receiver can perform a Quick Ack on the next pre-configured opportunity.

[0036]

[0067] 4 illustrates an example embodiment 110 using a reserved bit in an MPDU delimiter (non-OMG) set to a first state (e.g., 1) to indicate that a Quick Ack should be performed at the next Quick Ack opportunity (if there is an erroneous MPDU). Otherwise, the Quick Ack can be skipped even if all MPDUs have been received (e.g., including low priority MPDUs). Setting this reserved bit to a first state (e.g., "1") indicates that there are RTA MPDUs that precede the delimiter and the originator does not have a receiver Quick Ack for those RTA MPDUs. The originator can trigger a Quick Ack by simply modifying some (but not all) delimiters after the RTA MPDU.

[0037] 3.3.Long Packet from Source 3.3.1. Quick Ack on L2 using EDCA Explicit Acknowledgment with Retransmission on L1

[0070] The following describes a Quick Ack on Link 2 (L2) using EDCA Explicit Ack with Retransmission on Link 1 (L1).

[0038]

[0071] FIG. 5 shows an example original AMPDU 130 for link 1 132 that includes an RTA MPDU 134 , other STA AMPDUs 136 , other low priority traffic identifiers (TIDs) 138 , and padding 140 .

[0039]

[0072] Figure 6 shows an example embodiment 170 of EDCA Explicit Acknowledgement with Retransmission on L2 that improves upon example 130 of Figure 5. Communications are shown on Link 1 172 and Link 2 174. As in Figure 5, RTA MPDU 134, other STA AMPDU 136, and other low priority TID 138 are shown.

[0040]

[0073] In the embodiment 170 of Figure 6, the receiving MLD can send a Quick Ack on link 2 using EDCA 176 by performing CSMA / CA which requires an acknowledgement to the Quick Ack to detect collisions. Since there is a possibility of collisions and the BA 178 initiates a TXOP, the receiving MLD may require an acknowledgement similar to the deprecated legacy 802.11 procedure shown in Figure 7. In Figure 7, the delayed BA uses an Ack 180 that responds to the BA 178. Note that the BA 178 can include MCS / Nss feedback.

[0041]

[0074] The sender can explicitly acknowledge (Ack) the BA on L2. The sender is free to place the retransmitted data anywhere in the long packet, including replacing the original padding or replacing a lower priority MPDU. The receiver aborts (stops) retrying the BA after receiving the Ack.

[0042]

[0075] 6 also illustrates replacing some of the padding with a retransmission of the RTA MPDU. Specifically, as shown, the beginning of the padding is replaced with a short or long training field (S / LTF) 182, followed by a retransmission 184 of the RTA MPDU, followed by the still required padding 186.

[0043]

[0076] 7 illustrates an example embodiment 210 of multiple Ack attempts 216 in a delayed Block Ack between an originating STA 212 and a receiving STA 214. As shown, the setup includes an ADDBA request / response and Ack, followed by an MPDU, then a BAR from the originating side, and an Ack back from the receiving side. After this, the receiving side sends a BA and receives an Ack, completing the process (218). A tear down (DELBA) is then seen with the associated ACK.

[0044] 3.3.2. Quick Ack on L2 with EDCA Implicit Acknowledgment and Retransmission on L1

[0078] The following describes a quick Ack on link 2 (L2) with an EDCA implicit acknowledgement and a retransmission on link 1 (L1).

[0045]

[0079] 8 illustrates an example embodiment 190 of implicit acknowledgment and retransmission. Acknowledgment of the Quick Ack sent on L2 can be done implicitly by observing the retransmitted MPDU on L1. As in the previous figure, communication on Link 1 172 and Link 2 174 is seen, showing the RTA MPDU 134, other STA AMPDUs 136, and other low priority TIDs 138.

[0046]

[0080] As in the previous figure, EDCA 176 is shown with BA 178, but in this case it is followed by a period "T" 191. "T" is a predefined value that includes an error of one OFDM symbol. The start of the actual retransmission may be the first symbol on L1 after the period T, which is pre-configured in this case by way of example and not limitation. In the retransmission, S / LTF 192 is shown, followed by a retransmission 194 of the RTA MPDU, and several other low priority TIDs 196 and 198.

[0047]

[0081] If there is not enough time for a retransmission with the same PPDU after the period T, the retransmission can be performed with a different PPDU.

[0048] 3.3.3. EDCA with Retransmission on L1 Quick Ack on L2 with Implicit / Explicit Ack

[0083] The following describes a quick Ack on link 2 (L2) performed using EDCA implicit or explicit acknowledgement on retransmission on link 1 (L1).

[0049]

[0084] A modified short training field (STF) can signal the start of a retransmission (reTx) and can be followed by an LTF for the receiver to re-estimate the channel. Repetitions (e.g., missing tones) in the STF indicate that this is not a data symbol. The STF can be modified to be the same length as a data OFDM symbol.

[0050]

[0085] The MCS / Nss of the retransmitted MPDU can be indicated by the BA (determined by the receiving side) or by a special symbol (determined by the sending side).

[0051]

[0086] If the Ack frame is sent in a non-HT format, it may not be used for a Quick Ack. No TA information is present.

[0052]

[0087] If the receiver does not detect the start of a retransmission or an Ack to the BA, it may retry the BA.

[0053]

[0088] The amount or duration of data to be transmitted can be derived by the receiver. For example, this can be determined based on the Ack, MCS / Nss, and the number of symbols to solicit the acknowledged MPDU byte (and associated delimiter). If the sender has signaled the number of octets of the TID before the Ack time, the retransmission MCS / Nss, the receiver can derive the symbols required for the retransmission of the TID.

[0054]

[0089] The receiver may need to cache unfinished LDPC CWs that were interrupted by retransmissions.

[0055]

[0090] Different MCS new / Nss new If MCS is used for retransmission, the following applies: The retransmission itself can be an AMPDU (possibly without a SERVICE). The receiver must use the MCS of the retransmitted data. old and Nss old Since we know the number of bytes and the number of bits, we can derive the symbol when the retransmission is complete. The MCS / Nss of the next symbol is old and Nss old When new data (low priority data) is resumed, Nss old If it is switched back to , it may be followed by an LTF symbol or it may be followed by a data symbol.

[0056]

[0091] The receiver is Nss old It is assumed that the original channel estimates for the spatial streams are cached.

[0057]

[0092] The last symbol used to carry the retransmitted data may contain a portion of the new data (or a delimiter thereof) that follows it.

[0058] 3.3.4. EDCA with Retransmission at L2 Quick Ack at L2 with Implicit / Explicit Acknowledgement

[0094] The following describes a Quick Ack on Link 2 (L2) that includes an EDCA implicit or explicit acknowledgement of a retransmission on Link 2 (L2).

[0059]

[0095] In this section, we describe an alternative where retransmission is performed over L2. The operation of retransmission over L1 or L2 is included in the preamble, or preconfigured, or signaled with a special symbol. In this case, the retransmitted data is sent over L2 in response to a quick Ack in the same TXOP. Next, we present an embodiment for performing retransmission over an alternative link.

[0060]

[0096] 9 illustrates an example embodiment 230 of a downlink (DL) retransmission on an alternate link. The top portion of the figure shows the same basic transmission on Link 1 232 as shown in FIG. 5, including an RTA MPDU 134, other STA AMPDUs 136, other low priority traffic identifiers (TIDs) 138, and padding 140.

[0061]

[0097] However, the retransmission operation in this example is performed on link 2 234. The EDCA 236 is followed by a BA 238 from STA1, and the NAV is set (240) during which the AP retransmits (242) an RTA MPDU, to which STA1 responds with a BA 244.

[0062]

[0098] It should be noted that the NAV of BA(DL) in FIG. 9, or the UL length of TF(UL) in FIG. 10, can be determined using the method described in the previous section.

[0063]

[0099] If the original PPDU solicits multiple Quick Acks from the same recipient, the retransmitted PPDU in response to the first Quick Ack can be padded to protect the next Quick Ack in the same TXOP. In this case, a BA or Multi-STA BA (MBA) is used in response to the retransmitted data, and the second Quick Ack can be merged into a single BA. Such padding can be prohibited by configuration if there are other STAs that can perform Quick Acks. The BA used to obtain the TXOP can also serve a similar purpose as a Reverse Direction Grant (RDG), so that the AP can control the remaining portion of the TXOP for polling the second recipient STA.

[0064]

[0100] 10 illustrates an example embodiment 270 of Quick Ack timing for uplink (UL) data. At the top of the figure, the AP transmits a TF 276. The TF can indicate the Quick Ack timing for UL data as determined by the AP, or it can be indicated by a special symbol as determined by the STA.

[0065]

[0101] Trigger 276 triggers a UL transmission from the STA, which includes a preamble 277 followed by a special symbol 278, RTA MPDU-1 280, and RTA MPDU-2 282, as shown, followed by transmissions from other lower priority TIDs 284 and 286, one of which is illustratively padded (286).

[0066]

[0102] The AP can aggregate Quick Ack and UL retransmissions to or from different users into a single MU TXOP, as shown by the EDCA 236 containing two BA+TFs 238a, 238b, in response to which the STA performs retransmissions of MPDU-1 240a and MPDU-2 240b, to which the AP responds with an MBA 242.

[0067] 3.3.5. Behavior of an Initiator that Does Not Receive a Quick Ack When L2 Uses EDCA

[0104] When using EDCA over L2 for the Quick Ack, the Quick Ack may be delayed due to a Clear Channel Assessment (CCA) busy and the receiver will retry the Quick Ack if it does not receive confirmation of the Quick Ack. An originator that does not receive a Quick Ack after the indicated symbol can assume that the Quick Ack was lost but will be retransmitted or that the Quick Ack is delayed.

[0068]

[0105] There appears to be no reason for the originator to retransmit the complete data before receiving a Quick Ack. For example, the originator may choose to do nothing if it does not receive a Quick Ack. Based on the originator's behavior above, the Quick Ack may be a negative acknowledgment (NAK), or the receiver may not need to send a Quick Ack if no data is missing.

[0069]

[0106] Alternatively, in some cases, the receiver needs to send a Quick Ack even if there is no missing data. In this case, the originator can clear the retransmission buffer after getting the Quick Ack. At L1, a BA is also required after an AMPDU. The above NAK behavior may not apply to delimiter-based Ack requests, since the delimiter itself may not be recognized by the receiver in error.

[0070] 4. Long packet transmission from the receiving side 4.1. Shared Ack Resource Unit (RU) - Example 1

[0109] This section describes the receiver sending a long PPDU. If the receiver is an AP, it can allocate a Shared Ack RU to perform Quick Ack. The Shared Ack RU can be, for example, a Broadcast RU.

[0071]

[0110] An MPDU in an AMPDU can be acknowledged before the AMPDU is completed, for example, an Ack status can be returned at symbol n for a completed MPDU at symbols n to d.

[0072]

[0111] The Shared Ack RU on L2 can stream the Ack status of data d symbols received earlier on L1, for example (a) inserting the least significant bit (LSB) of the sequence number (SN) followed by several MPDUs received consecutively after the SN, or (b) inserting a CRC every few symbols, or (c) the RU can be specialized in that it contains only a few tones.

[0073]

[0112] The Shared Ack RU can also be used to indicate the NAV of another link NAV (e.g., L1 NAV) when not performing a quick acknowledgement. The L1 NAV can also include the ID of the TXOP owner on L1. The L1 NAV is the remaining duration of the L1 ongoing PPDU + the NAV duration of the NAV of the PPDU.

[0074]

[0113] FIG. 11 illustrates an example embodiment 310 of a Shared Ack RU, where communication between a STA and its AP occurs over Link 1 (L1) 312 and Link 2 (L2) 314 as shown.

[0075]

[0114] As shown, the shared Ack RUs on L2 (RUs carrying 318, 324, 326, 332, and 334) can stream the Ack status of data symbols received earlier on L1, for example (a) inserting the least significant bit (LSB) of the sequence number (SN) followed by several MPDUs received consecutively after the SN, and / or (b) inserting a CRC every few symbols, and / or (c) the RU can be specialized in that it contains only a few tones.

[0076]

[0115] In Figure 11, the Shared Ack RU (RU carrying 318, 324, 326, 332, and 334) can also be used to indicate the NAV of another link NAV (e.g., L1 NAV) when not performing a quick acknowledgement. The L1 NAV can also include the ID of the TXOP owner on L1. The L1 NAV is the remaining duration of the L1 ongoing PPDU + the NAV duration of the NAV of the PPDU.

[0077]

[0116] The AP includes a DL transmission with a preamble 317 and RUs directed to different STAs as shown. Notably, it is shown that one RU is used for Ack and NAV while DL data is sent (320, 322) to different STAs. In this example, STA1 and STA2 on L1 are hidden nodes, and STA2 initiates a TXOP first on L1 with a PPDU 316. Note that PPDU 316 does not receive STA2 (STA2 may be an OBSS STA, in which case there is no BA2). STA1 MSDU arrives and BO counter counts down to zero. However, STA1 defers channel access since it sees the L1 NAV from the L2 shared Ack RU. TXOPs initiated on L1 within the duration of the shared RU do not require RTS / CTS for hidden node detection. As shown, padding 318 follows the preamble 317, followed by the L1 NAV 324. The AP transmits BA2 326 to STA2.

[0078]

[0117] STA1 sees the Shared Ack RU and knows how long it will be delayed on L1, while STA2 (as the originator) receives a Quick Ack 326 for its PPDU and can perform a retransmission (reTx) in the same PPDU or in a new PPDU. The EDCA based channel access 328 delay is seen before the PPDU 330 from STA1, and the L1 NAV 332 is seen in the RU in the TXOP on L2. The AP responds to STA1 with BA1 334, and STA1 can also perform a retransmission if there is enough time remaining.

[0079] 4.2. Shared Ack Resource Unit (RU) - Example 2

[0119] Shared Ack RU also aids in collision detection, allowing colliding parties to immediately exit and retry.

[0080] 12 illustrates a second example Shared Ack RU embodiment 350, showing communication between the STAs and the AP over Link 1 (L1) 312 and Link 2 (L2) 314. In this example, the absence of an L1 NAV in the Shared RU on L2 indicates a collision after STA1 or STA2 transmission, which causes both STAs to back off.

[0081]

[0121] In particular, it is shown that DL data is transmitted (320, 322) to different STAs on L2 while one RU is used for Ack and NAV. In this example, a collision occurs (354) between STA1 and STA2 on link 1, but the RU for Ack on L2 has padding 352 and does not indicate receipt from either. Since the L1 NAV on L2 is missing, STA1 and STA2 detect the collision. Therefore, STA1 and STA2 end their transmissions early and initiate a BO.

[0082]

[0122] A backoff (BO) 356 is performed, after which STA1 gets the TXOP and sends a PPDU 358 on L1 to the AP, and the RU indicates L1 NAV 360 on L2. The AP responds with BA1 362, followed by further padding 363 if necessary.

[0083]

[0123] STA2 gets a TXOP on L1 after STA1, sends a PPDU 364, and its L1 NAV 366 is in the RU on L2. Because the PPDU from STA2 exceeds the duration of the Shared Ack RU, the AP sends the first part of the BA from the L2 RU as BA2a 368. Thus, the first part of the MPDU is acknowledged (Ack) by the Shared Ack RU (BA2a) 368, and the remaining part (or all MPDU) is acknowledged (Ack) by the regular BA (BA2b) 370 on L1.

[0084] 4.3.UL Zones to Increase Access Opportunities

[0125] Due to the shared Ack RU on L2 for transmissions on L1, the AP can create a UL zone on L1 that aligns with long PPDUs / TXOPs on L2, where the AP only receives and has access to the L1 secondary channel without having to consider alignment with PPDUs on other channels, increasing the chances of UL access.

[0085]

[0126] 13 illustrates an example embodiment 410 of a UL zone for increasing access opportunities. The figure shows communication between STAs and APs over link 1 (L1.2) 412 for ch2, link 1 (L1.1) 414 for ch1, and link 2 (L2) 416.

[0086]

[0127] The AP on L1 issues a UL zone announcement 420 covering a zone 428 on L1 and with a legacy NAV 426, as seen on ch2 422 and ch1 424. On L2, there is a DL transmission with a preamble 418 and DL (432, 434) performed on multiple RUs, another RU includes an Ack and NAV for L1.

[0087]

[0128] In this example, as in the previous figure, STA1 and STA2 on L1 experience a collision 436 of their preambles. Therefore, the AP does not carry the L1.1 NAV on L2, but instead pads 430 using a shared Ack RU. STA1 and STA2 detect a collision on L1.1 because they missed the L1.1 NAV on L2. In this case, STA1 and STA2 give up transmission and initiate a BO. After the BO, STA1 gets a TXOP on Link1 primary ch (L1.1) for a PPDU 440. This allows STA2 to block access on L1. On L2, the L1.1 NAV 444 is seen following the padding 430, which also allows STA2 to block access on L1 ch1.

[0088]

[0129] The AP created a UL zone 428 on L1 that is aligned with the long L2 DL PPDU. The UL zone announcement frame sets the NAV 426 for legacy STAs on L1 to prevent them from accessing L1. EHT STAs that recognize the UL zone announcement frame do not need to set their NAV and can still perform access and can perform parallel access on L1 ch2.

[0089]

[0130] STA2 performs EDCA access using the secondary channel (L1.2) on L1 since the primary channel is occupied, and the Shared Ack RU on L2 indicates the L1.2 NAV 446. No NAV sync delay is required since the UL zone announcement sets the NAV in L1.2. STA1 and STA2 may be hidden nodes, and STA2 uses the L1.1 NAV broadcast in the Shared Ack RU on L2 to determine if the primary channel is busy. The Shared Ack RU streams the Quick Ack 448 from the AP for both L1.2 and the first part of L1.1. In this example, the UL PPDU on the primary channel (L1.1) is extended beyond the UL zone 428, while the UL PPDU 440 is transmitted on the secondary channel (L1.2), the shared Ack RU is completed, and the last part of the Ack(BA1b) 450 for the last part of the PPDU 440 is transmitted on L1.1.

[0090] 5. Long packets sent from both sides 5.1. UL Heavy L1 + DL Heavy L2 Example

[0133] 14 illustrates an example UL Heavy L1+DL Heavy L2 embodiment 510. In this example, both links are shown to have long PPDUs. A Shared Ack RU on L2 is shown to provide Quick Ack and hidden node protection for L1.

[0091]

[0134] More specifically, the figure shows communication between an AP and a STA over Link 1 (L1) 512 and Link 2 (L2) 514. In this example, the AP transmits a TF 516 on L1, the STA transmits on L1, and the AP transmits DL data and communicates a Quick Ack over the RU in a transmission performed on L2.

[0092]

[0135] The L1 transmission includes a preamble 518a, followed by a special symbol 520, an RTA MPDU-1 524, an RTA MPDU-2 526, traffic from other lower priority TIDs 534, 536, retransmissions of both RTA MPDU-1 and RTA MPDU-2 536, 542, and padding 540, if required, as shown.

[0093]

[0136] At L2 after preamble 518b, in a Quick Ack RU on L2, L1 padding 522 is seen, after which the AP sends BA1+BA2 528 for MPDUs 524, 526. Later, the AP sends BA1 538 for the retransmission 536 of RTA MPDU-1, as shown. Since the retransmission of RTA MPDU-2 occurs at the end of the TXOP, the Ack for this 544 is sent by the AP on L1 after the TXOP as BA2+low priority MBA.

[0094] 5.2. Example of Ack RU in UL direction

[0138] The Shared Ack RU can be extended to the UL direction. An AP on L2 can schedule multiple Shared Ack RUs for multiple DL scheduled STA MLDs on L1 for Quick Ack. An AP on L2 can schedule one Shared Ack RU for multiple DL scheduled STA MLDs on L1 for Quick Ack using UL MU-MIMO or for Quick Ack using TDM.

[0095]

[0139] Figure 15 shows an example embodiment 610 in which an AP uses a TF on L2 to schedule start and / or end times for transmissions on a Shared Ack RU. Both MLD1 and MLD2 on L2 transmit a Trigger-Based (TB)-PPDU preamble for protection in neighboring networks. MLD2 stops transmitting after the preamble and resumes S / LTF transmissions at a specified time. The resumed transmission from MLD2 uses power and frequency estimated from information available in the TF.

[0096]

[0140] More specifically, the figure shows communication between the AP and MLD1 and MLD2 over link 1 (L1) 612, and between MLD1 and MLD2 and other STAs over link 2 (L2) 614. In this example, the AP transmits a TF 616 on L2. The STA starts transmitting on L2 and starts a TXOP transmission that also includes a Quick Ack RU. Meanwhile, the AP starts transmitting on L1.

[0097]

[0141] The transmission on L1 includes a preamble 618a, followed by a special symbol 622, an RTA MPDU-1 626 to MLD1, and an RTA MPDU-2 628 to MLD2, as shown, with communications from other lower priority TIDs 634, 636 to MLD1 and MLD2, respectively. There is also time in the TXOP for retransmissions 644, 648 of RTA MPDU-1 and RTA MPDU-2, and padding if necessary.

[0098]

[0142] The transmission on L2 includes a preamble 618b, followed by UL data 620, 621, and activity on the Quick Ack RU indicating the S / LTF 624, 638 determined from information transmitted on the TF 616. Additionally, the AP responds to RTA MPDU-1 with BA1 632 and RTA MPDU-2 with BA2 640. Padding 630, 642 is also shown in this RU.

[0099] 6. Process Flow Embodiments

[0144] 16 and 17 show an example embodiment 650 of receiver processing of long PPDUs requiring Ack. On a first link, the sender sends a long PPDU requiring acknowledgment. On a second link, the receiver sends a quick Ack to the sender.

[0100]

[0145] More specifically, in block 652, the receiver begins receiving a long PPDU on the first link. A check 654 determines which preamble or special symbol of the PPDU symbol is from among several options: (1) use a Quick Ack, (2) use a preconfigured Quick Ack configuration, or (3) do not require a Quick Ack.

[0101]

[0146] If the decision is option (1), then in block 656, the receiver applies the Quick Ack configuration from the special symbol and then proceeds to decision 660 to determine if all configured MPDUs on the first link up to the configured time have been received. If the condition is met, then in check 662, a check is made whether a Quick Ack should be optionally performed on the second link. If the condition is not met, execution returns to check 660. Otherwise, execution proceeds to block 664 of FIG. 17.

[0102]

[0147] Returning to consideration check 660, if the condition is not met, execution also passes to block 664 of FIG.

[0103]

[0148] Given the decision of option (2) from block 654, proceed to block 658 and apply the Quick Ack configuration from the pre-configuration, and then proceed to block 660 as previously described.

[0104]

[0149] Considering the decision of option (3) from block 654 , proceed to block 672 of FIG. 17 and perform a normal Ack / BA on the first link, after which execution returns to block 652 .

[0105]

[0150] 17, a Quick Ack is performed on the second link, after which a check 666 is performed to determine whether a Quick Ack or an Ack for a retransmission was received. If the condition is not met, execution returns to block 664.

[0106]

[0151] If not, in block 668, a quick retransmission is received on either the first or second link based on the configuration, and then execution proceeds to check 670 to determine if the PPDU of the first link is complete. If the quick Ack is complete, in block 672, a normal Ack / BA is performed on the first link and execution returns to block 652. If the quick Ack is not complete, execution transfers from check 670 to check 660 of FIG.

[0107]

[0152] 18 and 19 show an example embodiment 690 of origination processing of a long PPDU that requires an Ack. In block 692, the origination begins transmitting the long PPDU on the first link. In decision 694, it determines what type of preamble or special symbol it is. Option 1 uses a Quick Ack configuration with a special symbol, option 2 uses a pre-configured Quick Ack configuration, and option 3 does not require a Quick Ack.

[0108]

[0153] If option 1 or option 2 is selected, then after transmitting the symbol corresponding to the time at which the Quick Ack was constructed in block 698, execution proceeds to check 700 to determine whether the Quick Ack was received. If the condition is not met, execution returns to block 698.

[0109]

[0154] If the condition is met, execution proceeds to check 702 of Figure 19 where the originator determines whether to perform a Quick Ack using an Implicit Ack on the retransmission. If the condition is not met, in block 706, the originator performs an acknowledgement of the Quick Ack on the second link and execution proceeds to block 704.

[0110]

[0155] On the other hand, if the conditions of check 702 are met, then in block 704 a quick retransmission is performed on the first or second link based on the Quick Ack configuration. Execution proceeds to check 708 to determine if the PPDU of the first link is complete. If the PPDU is not complete, execution returns to block 698 of Figure 18. Otherwise, in block 710, the sender receives a normal Ack / BA on the first link and execution returns to block 692 of Figure 18.

[0111]

[0156] Considering the other options at block 694 of FIG. 18, if option 3 is selected, execution proceeds directly to block 710 of FIG. 19 (already described).

[0112] 7. Frame Format Embodiments

[0158] FIG. 20 illustrates an example embodiment 730 of the Quick Ack Configuration field. This field illustrates an example of the configuration described in the previous section. This field may be included in management frames such as ADDBA Action frames as described in the section on Ack Timing / Ack Link Indication in Long Packets. When this field is present in a frame from the originator to the receiver, it indicates pre-configuration of a Quick Ack. When this field is present in a frame from the receiver to the originator, it may indicate a proposed configuration and / or the ability to perform a particular Quick Ack configuration. When included as an element, the presence of the Element ID, Length, and Element ID Extension fields are implied and are not displayed.

[0113]

[0159] The fields may be included in preconfigured symbols or positions within the long PPDU. The subfields are not limited to this particular order, and a presence flag may precede a particular field to indicate its presence. The fields are described by way of example and not by way of limitation, although actual implementations may differ, such as utilizing signaling that serves a similar purpose as described below.

[0114]

[0160] The Link ID Bitmap subfield provides the identity of second links on which the originator may expect a Quick Ack. An originating transmitter uses this field to indicate links on which a Quick Ack may be received. A receiving transmitter uses this field to indicate links on which Quick Ack transmission may be supported. An originating receiver uses this field to recognize links on which the receiver may support Quick Acks for transmission. A receiver, in the case of a receiver, uses this field to determine (recognize) which links allow Quick Ack transmission.

[0115]

[0161] The t0 Start subfield describes the first t0 in the long PPDU, and its units can be, for example, OFDM symbol numbers or time from the start of the PPDU. The originating transmitter uses this field to indicate the first t0 in the long PPDU. The receiving receiver uses this field to determine the first t0 in order to perform the transmission of a Quick Ack. If the field is transmitted by the receiving side, the subfield can be omitted.

[0116]

[0162] The t0 Duration subfield indicates the duration between two successive t0s if multiple t0s are present. The units may be expressed in OFDM symbols. The originating transmitter uses this field to indicate the periodicity that the Quick Ack is requesting. The receiving receiver uses this field to determine (calculate) the subsequent t0s of the Quick Ack that includes the subfields "t0 Start" and "t0 Count". Multiple instances of t0 may be configured within the duration of a long PPDU transmitted on Link 1. The multiple instances of t0 may follow the periodicity provided in this subfield. If the field is transmitted by the receiver, the subfield may be omitted.

[0117]

[0163] The t0 Count subfield indicates the number of t0s if multiple t0s are present. The originating transmitter uses this field to indicate the number of Quick Acks requested. If such information is provided, this number must be less than or equal to the supported number indicated by the receiver. The receiving receiver uses this field to determine the t0 of subsequent Quick Acks that contain subfields "t0 Start" and "t0 Periodicity". As indicated in this subfield, multiple instances of t0 can be configured within the duration of a long PPDU transmitted on Link 1. The receiving transmitter can use this field to indicate the maximum (max) number of t0s supported per PPDU. The originating receiver can use this subfield to determine the settings of the subfields transmitted to the receiver.

[0118]

[0164] The Max t2-t1 subfield provides the preconfigured duration. In at least one embodiment, the units are OFDM symbols. This field can be set to a reserved value indicating that the mechanism is not used. The originating transmitter uses this field to indicate the preconfigured duration. The receiving receiver uses this field to determine the timeout within which an Implicit Ack for a Quick Ack should be received. If the field is transmitted by the receiver, the subfield can be omitted.

[0119]

[0165] The receiver (Rx) proposed / requested MCS / NSS subfield in at least one embodiment includes a flag indicating whether the originator expects receiver feedback to suggest an MCS / Nss. If the flag is set to a first state, true, the next two fields (retransmission MCS, retransmission Nss) can be reserved or omitted. The originating transmitter uses this field to indicate whether the receiver should provide a proposed MCS / Nss or request a quick retransmission MCS / Nss. If the originator does not want to propose or request a quick retransmission MCS / Nss from the receiver, it should set this subfield to false and indicate the retransmission (reTx) MCS / Nss (next subfield) of the NAV decision for a quick retransmission following a Quick Ack on the link on which the Quick Ack is transmitted, or if the MCS / Nss is not explicitly signaled in the quick retransmission or quick retransmission trigger. The receiving receiver uses this field to determine whether to propose or request an MCS / Nss for a quick retransmission in the Quick Ack. The receiver can also use the proposed or requested MCS / Nss to determine the NAV if a quick retransmission follows the Quick Ack on the link on which the Quick Ack was sent. The receiving transmitter uses this field to indicate whether it supports including the proposed / requested MCS / Nss in the Quick Ack. The originating receiver uses this subfield to determine how to set the same subfield from the originator to the recipient.

[0120]

[0166] The reTx MCS subfield indicates the MCS (or offset relative to the MCS of the original transmission) of the quick retransmission. The originating transmitter uses this field to indicate the (minimum) MCS or offset relative to the long PPDU MCS for the quick retransmission. The receiving receiver uses this field to determine the MCS of the quick retransmission if such information is not explicitly indicated in the quick retransmission or the quick retransmission trigger. The receiving receiver also uses this subfield to determine the NAV if the quick retransmission follows a quick Ack on the link on which the quick Ack is sent. If the field is sent by the receiver, the subfield can be omitted.

[0121]

[0167] The reTx Nss subfield indicates the Nss of the quick retransmission (or an offset relative to the Nss of the original transmission). The originating transmitter uses this field to indicate the (minimum) Nss or an offset relative to the long PPDU Nss for the quick retransmission. The receiving receiver uses this subfield to determine the Nss of the quick retransmission if such information is not explicitly indicated in the quick retransmission or the quick retransmission trigger. The receiving receiver also uses this subfield to determine the NAV if a quick retransmission follows a quick Ack on the link on which the quick Ack is sent. If the field is sent by the receiver, the subfield can be omitted.

[0122]

[0168] The TID Bitmap subfield identifies the TIDs to be reported in the Quick Ack. A transmitter, in the case of an originator, uses this field to indicate which received TIDs should be included in the Quick Ack. A receiver, in the case of a receiver, uses this field to determine the set of MPDUs whose reception status at t0 should be included in the acknowledgement frame. If the field is transmitted by a receiver, the subfield may be omitted. This subfield may be omitted if included in a management frame whose scope is limited to a specific TID (such as an ADDBA request frame).

[0123]

[0169] The on-demand t0 subfield can be implemented as a flag indicating that t0 is determined so that the originator can use training symbols or delimiters to indicate that RTA MPDUs are inserted before and after the indication. The pre-configured t0 can be implicitly replaced by either modified delimiters or inserted training symbols, making t0 an "on-demand" t0. If the flag indicates true, the t0 start / duration / count fields can be omitted or reserved. The originating transmitter uses this field to indicate t0 determined by the mechanism above. The receiving receiver uses this field to know whether a pre-configured Quick Ack should be applied. When set to true, the pre-configured t0 is replaced by a dynamically signaled t0. The receiving transmitter indicates whether the receiver supports on-demand t0. The originating receiver uses this field to avoid using the mechanism for receivers that do not support this feature.

[0124]

[0170] The reTx TXOP subfield for Quick Ack indicates that a Quick Ack will be followed by a Quick Retransmission on the link where the Quick Ack was sent. It indicates that the receiver can allocate a NAV in the Quick Ack for the Quick Retransmission. The originating transmitter uses this subfield to indicate that a Quick Ack will be followed by a Quick Retransmission on the link where the Quick Ack is sent. The receiving receiver uses this subfield to determine whether it should reserve a TXOP in the Quick Ack to be able to perform a Quick Retransmission on the link where the Quick Ack is sent. The receiving transmitter uses this field to indicate that it supports reserving a TXOP and receiving a Quick Retransmission on the link where the Quick Ack is sent. The originating receiver uses this field to determine whether it should set the same subfield to true if the receiver indicates support.

[0125]

[0171] FIG. 21 illustrates an example embodiment 750 of a special symbol configuration field. This field can be included in a management frame. When this special symbol configuration field is in a frame transmitted from an originator to a receiver, it indicates pre-configuration of special symbols for long PPDUs that require a Quick Ack. When this special symbol configuration field is in a frame from a receiver to an originator, it can indicate a proposed configuration and / or the ability to perform a specific configuration. When this special symbol configuration field is included as an element in a frame, the presence of the Element ID, Length, and Element ID Extension fields are implied and not displayed. The subfields are not limited to this particular order, and a presence flag can be present before the field to indicate the presence of a specific field.

[0126]

[0172] The illustrated special symbol configuration fields are presented by way of example and not by way of limitation, as this disclosure contemplates other configurations that may differ but provide signaling that serves a similar purpose as that described below.

[0127]

[0173] The Special Symbol MCS subfield indicates the MCS of the special OFDM symbol. If the transmitter is an originator, it sets this field to indicate the MCS used with the special symbol. If the receiver is a receiver, it accepts the special symbol using the MCS value indicated in this field. If the transmitter is a receiver, it sets this field to indicate whether it can accept the proposed MCS value for the special symbol and / or mixed MCS for symbols spanned by the codeword. If the receiver is an originator, it uses this field to determine whether it can enable the special symbol if the receiver supports it.

[0128]

[0174] The Special Symbol Nss subfield indicates the Nss of the special OFDM symbol. If the transmitter is an originator, it sets this field to indicate the Nss used for the special symbol. If the receiver is a receiver, it receives the special symbol using the Nss value indicated in this field. If the transmitter is a receiver, it sets this field to indicate whether it can receive the proposed Nss value of the special symbol and / or a mixed Nss of the symbols spanned by the codeword and / or whether it can use the training field of the non-special symbols to estimate the channel on which the special symbol is received. If the receiver is an originator, it uses this field to determine whether it can enable the special symbol if the receiver supports it.

[0129]

[0175] The Special Symbol Duration subfield indicates the duration of the special symbol. The unit value in at least one embodiment is the time from the start of the OFDM symbol or PPDU. A specific value (e.g., 0) is used to signal that the special symbol is not configured or supported. The transmitter, when it is the originator, sets this field to indicate the duration of the special symbol in a fixed size RU / subchannel. The actual duration is inversely scaled by a factor determined by the actual bandwidth to resource unit (BW / RU) size ratio and the fixed size. The receiver, when it is the receiver, uses this field to determine the duration of the special symbol subject to the above scaling. The transmitter, when it is the receiver, indicates the proposed duration of the special symbol and / or support for the special symbol. When it is the originator, the receiver uses this field to determine the receiver's support for the special symbol and whether it should be enabled.

[0130]

[0176] FIG. 22 illustrates an example embodiment 770 of a Quick Ack configuration in a special symbol, having the following subfields:

[0131]

[0177] The Pre-configuration Override subfield indicates the presence of the following Quick Ack Configuration and CRC fields. It indicates whether there is no Quick Ack based on pre-configuration from a previous management frame or a Quick Ack based on configuration carried in a special symbol used for the PPDU. This field can be a field in the preamble rather than a field in a special symbol. The sender / originator uses this field to indicate whether no Quick Ack based on pre-configuration from a previous management frame is used for the PPDU or whether a Quick Ack based on configuration carried in a special symbol is used for the PPDU.

[0132]

[0178] The receiver / side uses this field to determine the presence of the next Quick Ack Configuration field and to configure / enable the Quick Ack.

[0133]

[0179] The CRC field is determined (calculated) from the contents of the Quick Ack Configuration field, possibly together with the contents of the Service field. The transmitter uses this field to convey the CRC of the contents of the Quick Ack Configuration field, possibly together with the contents of the Service field. The receiver uses this field to check the accuracy of the contents of the Quick Ack Configuration field, and possibly the contents of the Service field. If incorrect, the receiver can either not perform a Quick Ack, perform a Quick Ack indicating that the MPDU was not received, or perform a Quick Ack based on a pre-configuration rather than the configuration indicated in the Quick Ack Configuration field.

[0134]

[0180] FIG. 23 illustrates an example embodiment 790 of a Shared Ack component that may be included in a management frame. When it is in a frame from the originator to the receiver, it represents pre-configuration of a Shared Ack RU from the AP on the second link of a DL long PPDU. When it is in a frame from the receiver to the originator, it may represent a proposed configuration and / or the ability to perform a particular configuration. When included as an element, the presence of the Element ID, Length, and Element ID Extension fields is implied and not displayed. The subfields are not limited to this particular order, and a presence flag may be present before the field to indicate the presence of a particular field. The field of this disclosure contemplates different embodiments while providing similar objectives as described below. The Shared Ack Configuration field has the following subfields:

[0135]

[0181] The Shared Ack AID subfield is used to derive the STA-ID of the RU used as a Shared Ack RU. The transmitter / AP uses this field to indicate the STA-ID to be used in allocating the Shared Ack RU in the long PPDU carrying the Shared Ack RU. If the long PPDU is DL, the allocation can be performed via the preamble of the long PPDU. If the long PPDU is TB-PPDU, the allocation can be performed using a trigger frame. The receiver uses this field to determine the STA-ID to be used for the allocated Shared Ack RU to listen to if the RU is in a DL PPDU, and to determine the Shared Ack RU to transmit for Quick Ack if the RU is in a TB-PPDU.

[0136]

[0182] The Delimiter Modulo subfield, when equal to the value x, represents the modulo that a delimiter signature exists every x octets in the Shared Ack RU. A transmitter sets this field to indicate that only octets with an octet count modulo of the value represented in this field equal to 0 can be used as the starting octet of a delimiter signature. A receiver uses this field to recognize that only octets with an octet count modulo of the value represented in this field equal to 0 can be used as the starting octet of a delimiter signature.

[0137]

[0183] FIG. 24 illustrates example embodiments 810, 830, and 850 of the Shared Ack RU element. Below, three example configurations of octets carried in the Shared Ack RU between one Delimiter Signature field and the next Signature field (not shown) are described: Padding 810, Quick Ack 830, or LNAV 850. The subfields are not limited to this particular order, and a presence flag may be present before the field to indicate the presence of a particular field. This field is described by way of example and not by way of limitation, and the present disclosure encompasses different embodiments serving similar purposes as described below. These embodiments have the following subfields:

[0138]

[0184] The Delimiter Signature subfield contains a special bit pattern that signals that the next field is a length field, which may only be placed in certain octets that satisfy the octet modulo as described on the previous page.

[0139]

[0185] The Length subfield indicates the length of the fields following the Length field until the next delimiter signature. The transmitter uses this field to indicate the number of octets, not including padding, until the next delimiter signature or the end of the transmission. The receiver uses this field to determine the start of padding before the next delimiter signature / end of the transmission.

[0140]

[0186] In the Padding Shared Ack RU 810, one or more Shared Ack Link IDs are provided, while the remaining embodiments 830 and 850 have a Link ID subfield and additional subfields.

[0141]

[0187] The Link ID subfield indicates the identity of the link to which the next LNAV or Quick Ack applies. If the Link ID is the same as the ID of the link carrying the Shared Ack RU, the octets up to the next Delimiter Signature are used as padding. The transmitter uses this field to indicate the Link ID to which the PPDU reception to which the Quick Ack responds, or the Link ID to which the Link NAV is associated, corresponds. The receiver uses this field to determine the identity of the link Quick Ack responding to, or the Link NAV to which it is associated.

[0142]

[0188] The Subchannel subfield contains the identity of the 20 / 40 / 80 / 160 MHz subchannel of the Link ID or the identity of the RU of the Link ID to which the next LNAV or Quick Ack applies. The transmitter sets this field to the previously signaled identity of the 20 / 40 / 80 / 160 MHz subchannel of the Link ID or the identity of the RU of the Link ID to which the next LNAV or Quick Ack applies. The receiver uses this field to determine the previously signaled identity of the 20 / 40 / 80 / 160 MHz subchannel of the Link ID or the identity of the RU of the Link ID to which the next LNAV or Quick Ack applies.

[0143]

[0189] The CRC Included subfield indicates whether there is a CRC field before the next delimiter signature. The transmitter uses this field to indicate the presence of a CRC field before the next delimiter signature. The receiver uses this field to determine whether there is a CRC field before the next delimiter signature.

[0144]

[0190] The LNAV / Ack subfield indicates whether the subsequent subfields preceding the next delimiter signature are used for Quick Ack or LNAV. The transmitter uses this subfield to indicate whether the subsequent fields up to the next delimiter signature are used for Quick Ack or LNAV. The receiver uses this field to determine whether the subsequent fields preceding the next delimiter signature are used for Quick Ack or LNAV.

[0145]

[0191] The Shared ACK RU of the Quick Ack configuration of the second embodiment also has the following subfields:

[0146]

[0192] The TID subfield indicates the TID to which the Quick Ack is responding. The transmitter uses this field to indicate the TID to which the Quick Ack is responding, along with the link ID and subchannel ID. The receiver uses this field to determine the TID to which the Quick Ack is responding, along with the link ID and subchannel ID.

[0147]

[0193] The TSSN subfield indicates the starting sequence number of a subsequent bitmap for the TID. The transmitter uses this subfield to indicate the starting sequence number of a subsequent bitmap for the TID indicated in the previous subfield. The transmitter uses this subfield to determine the starting sequence number of a subsequent bitmap for the TID indicated in the previous subfield.

[0148]

[0194] The Bitmap subfield provides a Quick Ack bitmap for the TID within the link signaled in the Link ID field and the subchannel / RU signaled in the Sub-Channel subfield. The transmitter uses this field to indicate the Quick Ack bitmap for the TID within the link signaled in the Link ID field and the subchannel / RU signaled in the Sub-Channel (Sub-ch) subfield. The receiver uses this subfield to determine the Quick Ack status of the SN represented by the bitmap for the TID within the link signaled in the Link ID field and the subchannel / RU signaled in the Sub-Channel subfield.

[0149]

[0195] The shared ACK RU of the link NAV configuration of the third embodiment has the following subfields as shown in the figure.

[0150]

[0196] The AID LSB subfield indicates the AID of the TXOP owner in the link signaled in the Link ID field and the subchannel / RU signaled in the Subchannel subfield. The transmitter uses this field to indicate the AID (or the LSB of the AID) of the TXOP owner in the link signaled in the Link ID field and the subchannel / RU signaled in the Subchannel subfield. The receiver uses this field to indicate the AID (or the LSB of the AID) of the TXOP owner in the link signaled in the Link ID field and the subchannel / RU signaled in the Subchannel field. The receiver can use this information to determine the presence of hidden nodes. The receiver can determine whether there was a collision in the PPDU transmission when it cannot detect its own AID in this field. In response to this detected collision, the transmission on the first link can be terminated early.

[0151]

[0197] The Remaining PPDU Duration + NAV subfield indicates the duration of the remaining PPDU plus the NAV signaled in the PPDU (possibly including the previous delimiter as the start of the duration). The transmitter uses this subfield to indicate the duration of the remaining PPDU plus the NAV signaled in the PPDU (possibly including the previous delimiter as the start of the duration). The receiver uses this subfield to determine the duration of the remaining PPDU plus the NAV signaled in the PPDU (possibly including the previous delimiter as the start of the duration). This subfield can be used by the receiver to determine the presence of hidden nodes.

[0152]

[0198] Each of these embodiments may include padding, and embodiments 2 and 3 may include a CRC subfield.

[0153]

[0199] The CRC subfield provides a cyclic redundancy check (CRC) of the octets following the CRC field of the last delimiter signature with corresponding CRC included set to true. The described CRC calculation may exclude the optional delimiter signature and length fields. The transmitter uses this field to indicate the CRC value of the octets following the CRC field of the last delimiter signature with corresponding CRC included set to true. The receiver uses this field to indicate the CRC value of the octets following the CRC field of the last delimiter signature with corresponding CRC included set to true.

[0154]

[0200] FIG. 25 shows an example embodiment 870 of a trigger frame with an additional subfield in the User Information List for use in a quick retransmission allocation. The transmitter uses the Other User Information field of the Quick Retransmission Allocation subfield to indicate the resource allocation for the quick retransmission in the solicited TB-PPDU. The subfields of this User Information List field, including the previous AID12 subfield, may be the same as the HE or EHT variant User Information field for the resource allocation immediately following the TB-PPDU. The receiver uses this field to determine the resource allocation for the quick retransmission in the solicited TB-PPDU. The subfields of this field, including the previous AID12 subfield, may be the same as the HE or EHT variant User Information field. The receiver may not find a User Information field that corresponds to its AID. In that case, the receiver does not have a Quick Ack and does not perform a quick retransmission.

[0155]

[0201] The TID / SSN / Bitmap subfields are the same as those described in the Shared Ack RU. The transmitter may indicate AID12 that is the same as AID12 of the immediately preceding user information field to indicate that the current user information field is used to carry a Quick Ack (i.e., TID / SSN / Bitmap) for the non-AP corresponding to AID12. The receiver may use AID12 that is the same as AID12 of the immediately preceding user information field to indicate that the current user information field is used to carry a Quick Ack (i.e., TID / SSN / Bitmap) for the non-AP corresponding to AID12.

[0156]

[0202] FIG. 26 illustrates an example embodiment 890 of a BA control field that includes quick retransmit MCS and Nss subfields in previously reserved bits.

[0157]

[0203] If the Rx Proposed / Requested MCS / NSS flag from originator to receiver is set to true, the transmitter uses this field to indicate the MCS and Nss (or an offset relative to the MCS / Nss of the original transmission) for a quick retransmission. This field may also indicate whether the indicated retransmission configuration is requested or proposed by the receiver.

[0158]

[0204] The receiver performs the quick retransmission based on its signaled MCS / Nss and the BW / RU size of the long PPDU on Link 1 if the quick retransmission is performed within the original Link 1 long PPDU, or based on the BW of the Quick Ack if the quick retransmission is performed after the Quick Ack on the same link. If MCS / Nss is requested, the sender MUST use the MCS / Nss indicated for the quick retransmission. If MCS / Nss is proposed, the sender MAY use a different MCS / Nss than the one indicated for the quick retransmission (e.g., a higher MCS / Nss).

[0159] 8. Overview of invention elements

[0206] The following is a summary of features and elements of the disclosure, including various cross-references of interdependence that refer back and forth to other elements within this summary (e.g., "x" or "xy" or "xyz"). This summary is not intended to limit the scope of the disclosure, but is intended to provide an overview of the elements and relationships.

[0160]

[0207] 1. An originating MLD can transmit a long PPDU on a first link. The long PPDU can consist of one or more AMPDUs to one or more receiving MLDs or STAs. The originating and receiving MLDs of the first link are abbreviated as originating or receiving in this disclosure.

[0161]

[0208] 2. The receiving MLD can perform an acknowledgment (Ack) by sending an acknowledgment frame on the second link before completing the transmission of the long PPDU on the first link. This is called a Quick Ack. The first and second links are assumed to be a simultaneous transmit / receive (STR) link pair of the receiving MLD.

[0162]

[0209] (a) There may be a time instance t0 associated with a Quick Ack agreed upon by the originating and receiving MLDs, which corresponds to a set X of MPDU(s) whose reception status is expected to be included in the acknowledgement frame.

[0163]

[0210] (b) For example, the set X may be restricted to all MPDUs that were completely transmitted before time t0 for the set of TIDs.

[0164]

[0211] (c) For example, set X may be all MPDUs that were completely transmitted before time t0'.

[0165]

[0212] (d) The acknowledgement frame may be a BA frame or a multi-STA BA frame.

[0166]

[0213] 3. The originating MLD may acknowledge the acknowledgement frame sent on the second link at time t1.

[0167]

[0214] (a) The absence of an Ack to an acknowledgement can be used by the receiving MLD to determine that there is an acknowledgement collision or error on the second link.

[0168]

[0215] (b) An Ack to the acknowledgement frame may be sent on the second link as an immediate response to the acknowledgement frame.

[0169]

[0216] (c) t1>t0. The difference between t1 and t0 may not be deterministic due to channel access delay on the second link. t1 is smaller than the end time of the long PPDU transmitted on the first link.

[0170]

[0217] 4. The sender may perform retransmission of missing MPDUs in set X of MPDUs described in element 2.a while the transmission of the long PPDU in element 1 is in progress. This is denoted as quick retransmission.

[0171]

[0218] (a) MPDUs in set X that were not reported as successfully received by the receiving MLD in the acknowledgement frame may be retransmitted if the acknowledgement frame is received by the originating MLD.

[0172]

[0219] (b) If the sender does not receive the acknowledgment frame for element 2, then retransmission may not be performed; or

[0173]

[0220] (c) If the sender does not receive the acknowledgment frame of element 2 and the frame is assumed to be sent by the receiver using EDCA, then a retransmission may not be performed.

[0174]

[0221] 5. The quick retransmission by the originating MLD in element 4 may occur within the same PPDU that has not yet finished being transmitted on the first link.

[0175]

[0222] 6. The quick retransmission by the originating MLD in element 4 can be performed on the second link (where the originator receives the acknowledgment frame) or on a third link supported by the receiving MLD.

[0176]

[0223] (a) The second or third link is a link to which a TID of an MPDU in set X is mapped.

[0177]

[0224] (b) The receiver can derive the NAV of the acknowledgement frame using the total number of octets in set X and (e.g., minus) the octets of the received MPDU in set X, and the BW / MCS / Nss of the quick retransmission. The acknowledgement frame is transmitted on the second link, followed immediately by a quick retransmission on the second link.

[0178]

[0225] (c) A quick retransmission can be within the same TXOP as a Quick Ack on the second link, for example as an immediate response to the Quick Ack.

[0179]

[0226] 7. Retransmission in element 5 may begin at time t2, and t2-t1<=preconfigured duration.

[0180]

[0227] (a) t1 is listed in element 3.

[0181]

[0228] (b) The originator may not need to perform an acknowledgment to the acknowledgment frame described in element 3.

[0182]

[0229] (c) The receiving MLD uses the start of retransmission on the first link as an acknowledgment to an acknowledgment frame sent on the second link.

[0183]

[0230] 8. Retransmission in element 5 may begin at time t2, which is independent of t1.

[0184]

[0231] (a) For example, the retransmission may occupy the time used for padding the original long PPDU, which may be an MU PPDU.

[0185]

[0232] (b) For example, the retransmission may begin at time t2, such that the receiving MLD does not need to buffer the interrupted LDPC codeword while receiving the retransmission.

[0186]

[0233] (c) For example, the retransmission may start at time t2, so that the receiving MLD does not need to buffer MPDUs that were interrupted during reception of the retransmission.

[0187]

[0234] (d) The interruptions in elements 8.b and 8.c are caused by retransmissions.

[0188]

[0235] 9. Retransmission of element 5 may begin with one or more training symbols.

[0189]

[0236] (a) At least one of the training symbols has a pattern that is distinguishable from ordinary data symbols.

[0190]

[0237] (b) Some of the training symbols can be used by the receiving MLD for new channel estimation.

[0191]

[0238] 10. The retransmissions in elements 5 and 6 may have a different MCS and Nss than the MCS and Nss of the original long PPDU in element 1.

[0192]

[0239] 11. The receiving MLD may still be required to send a BA on the first link as an immediate response to element 1's long PPDU.

[0193]

[0240] 12. The receiving MLD may not send an acknowledgement frame on the secondary link if set X of MPDUs described in element 2 are all correctly received, because the originating MLD's actions described in elements 4b or 4c will effectively treat the acknowledgement frame on the second link as a NAK.

[0194]

[0241] 13. The receiving MLD may send an acknowledgement frame on the secondary link if the set X of MPDUs described in element 2 are all correctly received. This may help the originating MLD to remove successful MPDUs from its (re)transmission buffer / advance transmission window before the acknowledgment described in element 11.

[0195]

[0242] 14. Quick Ack configuration information may be provided to the recipient prior to the Quick Ack. The configuration may include:

[0196]

[0243] (a) t0 as described in element 2, the (minimum) configuration for quick retransmission (e.g., MCS / Nss / BW) in elements 5 and 6, the identity of the link for the quick Ack and quick retransmission, the TID (whose reception status must be included in the Quick Ack), and the preconfigured period as described in element 7.

[0197]

[0244] (b) There may be multiple instances of t0 configured within the duration of the long PPDU transmitted on Link 1. The multiple instances of t0 may follow a periodicity also provided in the Quick Ack configuration.

[0198]

[0245] 15. All or part of the Quick Ack configuration information may be pre-configured.

[0199]

[0246] (a) The above pre-configuration can be turned on or off based on a field in the preamble or the first few symbols in the data field of the element 1 long PPDU.

[0200]

[0247] (b) The Quick Ack configuration may be signaled prior to data exchange via the ADDBA request / response mechanism or other management frames.

[0201]

[0248] (c) The Quick Ack configuration may include MCS / Nss / BW differences from the original transmission.

[0202]

[0249] 16. All or part of the Quick Ack configuration information may be signaled within the element 1 long PPDU.

[0203]

[0250] (a) The signaling may be present in the preamble of the long PPDU.

[0204]

[0251] (b) Signaling may be present within the first few symbols of the data field of an AMPDU in a long PPDU, denoted as special symbols. (1) The special symbols may have a reduced MCS or Nss compared to the rest of the data symbols. (2) The configuration of the special symbols may be signaled via the ADDBA request / response mechanism or other management frames prior to data exchange.

[0205]

[0252] 17. The (proposed / requested) configuration for quick retransmission may be included in the Quick Ack. The configuration may include (min / max) MCS or (min / max) Nss for quick retransmission. The originating MLD may not use the proposed configuration for quick retransmission. Also, the originating MLD may be requested to use the requested configuration for quick retransmission.

[0206]

[0253] 18. The enablement of the Quick Ack configuration may not be determined at the beginning of a long PPDU.

[0207]

[0254] (a) For example, an MSDU for TID i that requires a Quick Ack (pre-configured for a Quick Ack) has not arrived at the MAC layer at the start of a long PPDU. The originator does not know to solicit a Quick Ack at the start of a long PPDU. For example, a pre-configured Quick Ack is not turned on in the preamble in element 15.

[0208]

[0255] (b) The originator may modify the contents of the portion of the AMPDU not yet transmitted to include the newly arrived MPDU of TID i preconfigured for Quick Ack.

[0209]

[0256] (c) The originator may set the reserved bit of the delimiter inserted after the inserted newly arrived MPDU of TID i to "1", denoted as modified delimiter. (1) The MPDU length field of the delimiter with the reserved bit set to 1 may represent the total length of the TID (e.g., TID i) preconfigured for Quick Ack and transmitted before the delimiter. (2) More than one such modified delimiter may be inserted after the insertion MPDU of TID i to avoid some delimiters being received in error. (3) The appearance of the modified delimiter in the received AMPDU indicates that the preconfigured Quick Ack configuration is on. The time at which the modified delimiter is transmitted may implicitly replace the preconfigured t0. (4) The information in (a) may be used to set the NAV of the acknowledgment frame of element 6, immediately followed by a quick transmission on the second link. The receiver can determine the NAV using the length signaled in element 18.a and (e.g., minus) the length of the corrected received MPDU preconfigured for the Quick Ack, and the Quick Retransmit MCS / Nss / BW.

[0210]

[0257] (d) The originator may insert one or more training symbols as described in element 9 before and / or after the newly arrived MPDU with inserted TID i. This signals that Quick Ack is on. (1) The time at which the training symbols are transmitted may implicitly replace the preconfigured t0. (2) The number of symbols between the previous and next training symbols is used to set the NAV of the acknowledgement frame in element 6, similar to element 18.c(4).

[0211]

[0258] 19. The receiver sends an acknowledgment as an immediate response to the quick retransmission on the second link as described in element 6c.

[0212]

[0259] (a) The acknowledgment not only reports the status of the retransmission, but can also act as a second Quick Ack for a long PPDU in progress on the first link, in which case the first Quick Ack, the first quick retransmission, and the second Quick Ack (+Ack for the first quick retransmission) are in the same TXOP on the second link.

[0213]

[0260] (b) The receiver may delay sending the first Quick Ack (e.g., wait with EDCA counter 0) or the sender may pad the quick retransmission in order to send a second Quick Ack in the same TXOP that satisfies the corresponding t0 requirement of element 14b.

[0214]

[0261] 20. In element 6c, if the receiver is an AP MLD, the Quick Acks may be aggregated / consolidated into the trigger frame.

[0215]

[0262] (a) If the long PPDU on the first link is a TB? PPDU, the AP can multiplex Quick Acks for several non-AP MLDs in a DL OFDMA PPDU and include a PSDU for each non-AP MLD, i.e., an AMPDU containing a Quick Ack and a trigger frame.

[0216]

[0263] (b) The Quick Ack can be integrated into a trigger frame that is sent to one or more non-AP STAs and allocates resources for quick retransmission. (1) The Ack bitmap, TID, and starting sequence number can be in a separate User Information field that contains a special AID or the same AID as the user's AID. The User Information field carrying the Quick Ack can immediately follow the User Information field of the non-AP MLD quick retransmission allocation.

[0217]

[0264] 21. The previous bullet describes a scenario where a long PPDU is sent by the originator on a first link while a quick ACK is sent by the receiver on a second link, and the receiver may be the TXOP owner on the second link.

[0218]

[0265] 22. The Motivation and Assumptions section describes a scenario where a PPDU is transmitted on a first link by the sender while there is an ongoing long PPDU being transmitted on a second link by the receiver.

[0219]

[0266] 23. If the receiver is an AP MLD, it may allocate an RU called Shared Ack RU in the long PPDU sent by the AP MLD on the second link.

[0220]

[0267] 24. A Quick Ack for the PPDU is sent on the first link and is sent in the Shared Ack RU. Furthermore, upon successful reception of the preamble on the first link (when the AP-MLD has not yet received another PPDU on the first link on the same frequency resource), the AP MLD can broadcast the first link NAV (remaining PPDU duration on the first link + NAV of the PPDU) and the identity of the transmitter of the PPDU is sent on the first link.

[0221]

[0268] (a) Addressing of the Shared Ack RU can be based on a broadcast AID or a special AID pre-signaled to the originating non-AP MLD.

[0222]

[0269] 25. The Quick Ack information sent in the Shared Ack RU may be the starting sequence number (e.g., LSB only), followed by a bitmap (or the number of consecutively received MPDUs following the starting sequence number), and padding, with the pattern repeating for the next group of received MPDUs. There may be a CRC and / or tail bits inserted at a preconfigured periodicity.

[0223]

[0270] (a) The coding can be BCC so that when an MPDU is received, the status can be coded and sent immediately on the shared Ack RU without codeword delay.

[0224]

[0271] (b) A quick Ack information for an MPDU may be sent before the AMPDU finishes transmitting on the first link.

[0225]

[0272] (c) An AP MLD may not send a BA / Ack as an immediate response to a PPDU sent by a non-AP MLD supporting Shared Ack RU if all reception statuses of the PPDU are sent as a Quick Ack in the Shared Ack RU.

[0226]

[0273] (d) The Ack status carried in a Quick Ack is called Quick Ack information.

[0227]

[0274] There may be a configured maximum delay between the time an MPDU is transmitted by the sender on the first link and the time a reception status must be transmitted on the shared Ack RU if the MPDU is received.

[0228]

[0275] 27. The NAV and identity information on the shared Ack RU can signal to other non-AP MLDs operating on the first link that the first link NAV is busy to avoid the hidden terminal problem on the first link.

[0229]

[0276] (a) RTS / CTS may not be required for MLDs that support Quick Ack in a Shared Ack RU.

[0230]

[0277] (b) The non-AP MLD may observe that there is no first link NAV broadcast in the Shared Ack RU and infer that there is a collision in transmission to the AP on the first link.

[0231]

[0278] 28. When PPDU1 transmitted on link 1 from a non-AP MLD overlaps in time with two or more DL PPDUs on the second link within the same TXOP, the Shared Ack RUs on more than one DL PPDU on the second link can carry Quick Ack information of different MPDUs of PPDU1.

[0232]

[0279] 29. The AP MLD can transmit one or more long PPDUs, each containing a Shared Ack RU, on the second link in the same TXOP. The AP MLD can transmit a control frame UL Zone Announcement in legacy duplicated format on the channel of the first link. The NAV of the UL Zone Announcement frame overlaps with the duration of one or more long PPDUs in the same TXOP on the second link.

[0233]

[0280] 30. UL Zone Announcement prevents legacy STAs from accessing the first link within the NAV duration, but non-AP MLDs supporting Shared Ack RU on the second link do not set NAV. In addition to media contention / EDCA on the primary channel of the first link, non-AP MLDs supporting Shared Ack RU on the second link can initiate independent media contention / EDCA on the secondary channel of the first link. Duplicate UL Zone Announcement frames on the secondary channel can enable NAV synchronization without moderate synchronization delay for independent EDCA procedures on the secondary link.

[0234]

[0281] (a) By performing multiple EDCA accesses on different channels of the same link, the situation where a low priority user occupies the primary channel and blocks access for other high priority users is avoided.

[0235]

[0282] (b) The AP may request the first link access not to occupy the secondary channel over a certain BW using PIFS sensing procedure on the secondary channel within the NAV duration of the UL zone announcement. For example, within the UL zone, the AP may only allow PIFS sensing of the secondary 20 MHz channel for a PPDU BW of up to 40 MHz. The 80 MHz BSS bandwidth on the first link may be used as two 40 MHz channels with independent access.

[0236]

[0283] (c) Within the UL Zone Announcement NAV duration of the first link, the AP is always listening on the primary and secondary channels on the first link, so a non-AP MLD supporting Shared Ack RU on the second link does not need to take into account the AP's activity on one channel of the first link when accessing another channel of the first link.

[0237]

[0284] 31. There may be several Shared Ack RUs on each long PPDU on the second link to be used for Quick Acks or first link NAVs corresponding to the same number of independent accesses on the first link in the UL zone.

[0238]

[0285] (a) There may be a single Shared Ack RU on the second link, which multiplexes multiple Quick Ack / first link NAVs corresponding to the number of independent accesses on the first link in the UL zone.

[0239]

[0286] 32. The STAs on the first link revert to monitoring the primary link only for channel access after the end of the UL zone.

[0240]

[0287] (a) A PPDU that occupies the primary channel on the first link that starts in the UL zone can terminate outside the UL zone. A PPDU that does not occupy the primary channel on the first link that starts in the UL zone may need to terminate within the UL zone.

[0241]

[0288] 33. The previous element describes the scenarios where (1) a long PPDU is sent from an initiator on a first link while the second link is performing a Quick Ack, or (2) a long PPDU sent from an AP MLD receiver on a second link with a Quick Ack to the PPDU on the first link. The following elements describe a long PPDU sent by an initiator on a first link and a long PPDU sent from a receiver on a second link with a Quick Ack.

[0242]

[0289] 34. If the sender is a non-AP MLD on the first link and the receiver is an AP MLD transmitting on the second link, the Shared Ack RU from the previous section of elements is also used for the Quick Ack and first link NAV.

[0243]

[0290] (a) If the long PPDU on the first link is a TB? PPDU, then there can be multiple Shared Ack RUs per user on the first link, as in element 31, or there is a single Shared Ack RU that multiplexes quick Acks to multiple users on the first link, as in element 31.a.

[0244]

[0291] 35. When the sender is an AP MLD on the first link while a non-AP MLD sends a TB-PPDU on the second link:

[0245]

[0292] (a) For each non-AP MLD addressed by a PPDU on the first link, there may be a corresponding Ack RU assigned to the second link to quick acknowledge (Ack) the PPDU on the first link. For example, the quick Ack is FDM on the second link. The mapping of the user on the first link and the corresponding Ack RU may be signaled in the preamble of the PPDU on the first link or in a trigger frame preceding the TB-PPDU on the second link.

[0246]

[0293] (b) For non-AP MLDs addressed by PPDUs on the first link, they can use the same Shared Ack RU in the second link for Quick Acks, such as Quick Acks as TDM on the second link. (1) The trigger frame that assigns the Shared Ack RUs preceding the TB-PPDU can provide the start time, transmission duration, and periodicity corresponding to each user in the DL PPDU on the first link. (2) All non-AP MLDs transmitting on Shared Ack RUs at different times can transmit all preambles of the TB-PPDU for protection. (3) For non-AP MLDs transmitting on Shared Ack RUs at different times, the trigger frame can be used to determine the transmit power and center frequency corrections. Each user's Quick Ack transmission in the Shared Ack RU can be preceded by an EHT-STF or EHT-LTF from the user.

[0247]

[0294] (c) The trigger frame on the second link may not be transmitted before the DL PPDU on the first link. If the second link has an earlier EDCA access opportunity than the first link, the DL PPDU may be transmitted on the second link, while the TB-PPDU containing the trigger frame and the Ack RU may be transmitted on the first link.

[0248] 9. General Scope of the Embodiments

[0296] Embodiments of the technology may be described herein with reference to flow diagrams of methods and systems according to embodiments of the technology, and / or procedures, algorithms, steps, operations, formulas, or other computational expressions, which may also be implemented as computer program products. In this regard, each block or step of the flowchart, and combinations of blocks (and / or steps) of the flowchart, and any procedures, algorithms, steps, operations, formulas, or computational expressions, may be implemented by various means, such as hardware, firmware, and / or software that includes one or more computer program instructions embodied in the form of computer readable program code. As will be appreciated, any such computer program instructions may be executed by one or more computer processors, including, but not limited to, a general purpose computer or a special purpose computer, or other programmable processing device to produce a machine, such that the computer program instructions executing on the computer processor(s) or other programmable processing device produce means for implementing the specified function(s).

[0249]

[0297] Thus, the blocks of the flowcharts and procedures, algorithms, steps, operations, formulas, or computational expressions described herein support combinations of means for performing a particular function(s), combinations of steps for performing a particular function(s), and computer program instructions for performing a particular function(s) as embodied in computer readable program code logic means. It will also be understood that each block of the flowcharts and any procedures, algorithms, steps, operations, formulas, or computational expressions described herein, and combinations thereof, can also be implemented by a dedicated hardware-based computer system that performs the particular function(s) or step(s), or a combination of dedicated hardware and computer readable program code.

[0250]

[0298] Moreover, these computer program instructions, embodied in computer readable program code or the like, may be stored in one or more computer readable memories or memory devices capable of directing a computer processor or other programmable processing device to function in a particular manner, such that the instructions stored in these computer readable memories or memory devices produce an article of manufacture including instruction means for implementing the functions specified in the flowchart(s). The computer program instructions may be executed by the computer processor or other programmable processing device to generate a computer-implemented process by causing a series of operational steps to be performed on the computer processor or other programmable processing device, such that the instructions executing on the computer processor or other programmable processing device provide steps for implementing the functions specified in the flowchart(s) block(s), procedure(s), algorithm(s), step(s), operation(s), mathematical formula(s), or computational expression(s).

[0251]

[0299] Additionally, the terms "program" or "program executable" as used herein will be understood to mean one or more instructions executable by one or more computer processors to perform one or more functions described herein. The instructions may be embodied in software, firmware, or a combination of software and firmware. The instructions may be stored locally on a non-transitory medium of the device or remotely, such as on a server, or all or a portion of the instructions may be stored locally or remotely. Remotely stored instructions may be downloaded (pushed) to the device upon user initiation or automatically based on one or more factors.

[0252]

[0300] Furthermore, as used herein, the terms processor, hardware processor, computer processor, central processing unit (CPU), and computer are used synonymously to indicate a device capable of executing instructions and communicating with input / output interfaces and / or peripheral devices, and it will be understood that the terms processor, hardware processor, computer processor, CPU, and computer are intended to include single or multiple devices, single-core devices and multi-core devices, and variations thereof.

[0253]

[0301] From the description herein, it will be understood that the present disclosure includes multiple implementations of the techniques, including but not limited to the following.

[0254]

[0302] An apparatus for wireless communication in a network, the apparatus comprising: (a) a wireless communication circuit, the wireless communication circuit operating as a wireless station (STA) in a multi-link device (MLD), as an access point (AP) STA or a non-AP STA, for wirelessly communicating with other wireless stations (STAs) using a carrier sense multiple access with collision avoidance (CSMA / CA) mechanism on a wireless local area network (WLAN) in which enhanced distributed channel access (EDCA) is utilized for random channel access on all links; (b) a processor coupled to the wireless communication circuit for operating on the WLAN; and (c) a non-transitory memory storing instructions executable by the processor for communicating with other STAs, and (d) the instructions, when executed by the processor, configure a wireless communication circuit for the wireless communication circuit. 1. An apparatus for performing steps of a communications protocol, the steps including: (d)(i) transmitting a long physical layer protocol data unit (PPDU) including one or more aggregated MAC protocol data units (AMPDUs) on a first link of an originating MLD; (d)(ii) receiving an acknowledgement (Ack) frame as a quick Ack from a receiving MLD on a second link before the originating MLD completes transmission of the long PPDU on the first link; and (d)(iii) the first and second links to the originating MLD and receiving MLD are a simultaneous transmit / receive (STR) link pair.

[0255]

[0303] An apparatus for wireless communication in a network, the apparatus comprising: (a) a wireless communication circuit, the wireless communication circuit operating as a wireless station (STA) in a multi-link device (MLD), as an access point (AP) STA or a non-AP STA, for wirelessly communicating with other wireless stations (STAs) using a carrier sense multiple access with collision avoidance (CSMA / CA) mechanism on a wireless local area network (WLAN) in which enhanced distributed channel access (EDCA) is utilized for random channel access on all links; (b) a processor coupled to the wireless communication circuit for operating on the WLAN; and (c) a non-transitory memory storing instructions executable by the processor for communicating with other STAs, the instructions, when executed by the processor, performing steps of a wireless communication protocol for the wireless communication circuit, the steps including: (d) (i) detecting one or more aggregated MAC protocols on a first link of an originating MLD; (d)(ii) before the initiator completes transmission of the long PPDU on the first link, the initiator receives an acknowledgement (Ack) frame from the recipient MLD on a second link as a Quick Ack; (d)(iii) the first and second links to the initiator MLD and recipient MLD are a simultaneous transmit / receive (STR) link pair; and (d)(iv) the initiator MLD and recipient MLD agree on a time instance t0 associated with a Quick Ack agreed upon by the initiator and recipient MLD that corresponds to a set X of MPDUs whose reception status is included in the acknowledgement frame.

[0256]

[0304] 1. A method for performing wireless communication in a network, the method comprising: (a) performing wireless communication in a wireless station (STA) of a multi-link device (MLD), the wireless station (STA) operating as an access point (AP) STA or a non-AP STA for wirelessly communicating with other wireless stations (STAs) using a carrier sense multiple access with collision avoidance (CSMA / CA) mechanism in a wireless local area network (WLAN) in which enhanced distributed channel access (EDCA) is utilized for random channel access on all links; (b) transmitting a long physical layer protocol data unit (PPDU) including one or more aggregated MAC protocol data units (AMPDUs) on a first link of an originating MLD; (c) before the originating MLD completes transmission of the long PPDU on the first link, the originating MLD receives an acknowledgement (Ack) frame as a quick Ack from a receiving MLD on a second link; and (d) the first and second links to the originating MLD and receiving MLD are a simultaneous transmit / receive (STR) link pair.

[0257]

[0305] The apparatus or method of any of the preceding implementations, wherein the originating MLD and the receiving MLD agree on a time instance t0 associated with a Quick Ack agreed upon by the originating and receiving MLDs that corresponds to a set X of MPDUs for which a reception status is included in the acknowledgment frame.

[0258]

[0306] An apparatus or method of any preceding implementation, wherein the set X is limited to all MPDUs that were completely transmitted before time t0 for a set of traffic identifiers (TIDs).

[0259]

[0307] An apparatus or method of any preceding implementation, wherein the set X is limited to all MPDUs that were completely transmitted before time t0.

[0260]

[0308] An apparatus or method of any preceding implementation, wherein the acknowledgement frame comprises a block acknowledgement (BA) frame or a multi-STA (MU) BA frame.

[0261]

[0309] As used herein, the term "implementation" is intended to include, but is not limited to, an embodiment, example, or other form of implementing the techniques described herein.

[0262]

[0310] As used herein, the singular words "a," "an," and "the" may include plural references unless the context clearly dictates otherwise. Reference to an item in the singular does not mean "one and only one" unless expressly stated otherwise, but rather means "one or more."

[0263]

[0311] Phrasal constructs within this disclosure such as "A, B and / or C" refer to any combination of items A, B, and C, where either A, B, or C can be present. Phrasal constructs such as "at least one of" followed by a group of listed elements indicate that at least one of the group elements is present, and, where applicable, includes any possible combinations of the listed elements.

[0264]

[0312] Reference herein to "an embodiment," "at least one embodiment," or similar embodiment terminology indicates that a particular feature, structure, or characteristic described in connection with the described embodiment is included in at least one embodiment of the present disclosure. Thus, these various embodiment phrases do not necessarily all refer to the same embodiment, or to a specific embodiment that differs from all other embodiments described. The embodiment phrase should be interpreted to mean that the particular features, structures, or characteristics of a given embodiment can be combined in any suitable manner into one or more embodiments of the disclosed devices, systems, or methods.

[0265]

[0313] As used herein, the term "set" refers to a collection of one or more objects. Thus, for example, a set of objects can include a single object or multiple objects.

[0266]

[0314] Relative terms such as first and second, top and bottom, upper and lower, left and right, etc. may be used only to distinguish one entity or action from another, and do not necessarily require or imply any such actual relationship or ordering between such entities or actions.

[0267]

[0315] The terms "comprises," "comprising," "has," "having," "includes," "including," "contains," "containing," or any other variations of these terms, are intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus that comprises, includes, contains, or has a list of elements may include other elements not specifically listed or inherent to such process, method, article, or apparatus, rather than including only those elements. An element introduced by "comprises...a," "has...a," "includes...a," or "contains...a" does not, in the absence of further constraints, exclude the presence of additional identical elements within the process, method, article, or apparatus that comprises, includes, contains, or has that element.

[0268]

[0316] As used herein, the terms "approximately", "approximate", "substantially", "essentially" and "about" or any other version of these terms are used to describe and explain slight variations. When used in relation to events or circumstances, these terms can mean that these events or circumstances will definitely occur and that these events or circumstances are highly likely to occur. When used in relation to a numerical value, these terms can mean a variation range of ±10% or less, such as ±5% or less, ±4% or less, ±3% or less, ±2% or less, ±1% or less, ±0.5% or less, ±0.1% or less, or ±0.05% or less of the numerical value. For example, being "substantially" aligned can mean an angle variation range of ±10% or less, such as ±5° or less, ±4° or less, ±3° or less, ±2° or less, ±1° or less, ±0.5° or less, ±0.1° or less, or ±0.05° or less.

[0269]

[0317] In addition, amounts, ratios, and other numerical values ​​may be expressed in range format in this specification. Such range formats are used as a shorthand for convenience, and include numerical values ​​explicitly specified as the limits of the range, but should be understood to flexibly include all individual numerical values ​​or subranges within the range as if each of these numerical values ​​and subranges were explicitly set forth. For example, a ratio within the range of about 1 to about 200 should be understood to include the explicitly recited limits of about 1 and about 200, but also include individual ratios such as about 2, about 3, about 4, and subranges such as about 10 to about 50, about 20 to about 100, etc.

[0270]

[0318] The term "coupled," as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically connected. A device or structure that is "configured" in a particular way is configured in at least that way, but may also be configured in other ways not recited.

[0271]

[0319] Benefits, advantages, solutions to problems, and any element(s) that may result in or make more evident any benefit, advantage, or solution should not be construed as a critical, necessary, or essential feature or element of the technology described herein or any or all of the claims.

[0272]

[0320] Moreover, in the above disclosure, various features may be grouped together in various embodiments for brevity of the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Inventive subject matter may be embodied in less than all features of a single disclosed embodiment.

[0273]

[0321] The Abstract of the Disclosure is presented to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

[0274]

[0322] It is understood that some jurisdictions have a practice of requiring the deletion of one or more portions of the present disclosure after filing. Therefore, the reader should refer to the application as of its filing date for the original content of the disclosure. The deletion of any of the disclosure content should not be construed as an abandonment, forfeiture, or public disclosure of any subject matter of the application as originally filed.

[0275]

[0323] The following claims are hereby incorporated into this disclosure, with each claim standing on its own as separately claimed subject matter.

[0276]

[0324] Although the description herein contains many details, these should not be construed as limiting the scope of the disclosure, but merely as exemplifying some of the presently preferred embodiments, and therefore the scope of the disclosure will be understood to fully embrace other embodiments that may become apparent to those skilled in the art.

[0277]

[0325] All structural and functional equivalents of the elements of the embodiments of the present disclosure known to those skilled in the art are expressly incorporated herein by reference and are intended to be included in the scope of the claims. Moreover, no element, component, or method step of the present disclosure is intended to be publicly disclosed, regardless of whether they are explicitly recited in the claims. No claim element herein should be construed as a "means-plus-function" element unless the element is explicitly recited using the phrase "means for". No claim element herein should be construed as a "step-plus-function" element unless the element is explicitly recited using the phrase "step for". [Explanation of symbols]

[0278] 10 Example of embodiment 12 Circuits 14 External I / O connections / buses 16 Internal Bus 18 CPUs / Processors 20 Memory 22 Modem 24,28 RF Module 26a, 26b, 26c, ... 26n, 29 Antenna 40 Example of embodiment 42 ST 1 44STA2 46 STATION 48 MLD Management Entity 50 CPU 52 Memory (RAM) 54 Modem 56 RF circuit 58 Bus 60a, 60b, 60c, ..., 60n antennas 62 CPU 64 Memory (RAM) 90 Example of embodiment 130 Original AMPDU example 132 Link 1 134 RTA MPDU 136 Other STA AMPDUs 138 Other low priority TIDs 140 Padding 170 Example of embodiment 172 Link 1 174 Link 2 176 EDCA 178 BA 180 Ack 182 S / LTF 184 RTA MPDU retransmission 186 Padding 190 Example of embodiment 191 Period T 192 S / LTF 194 RTA MPDU retransmission 196,198 Other low priority TIDs 210 Example of embodiment 212 Caller 214 Receiver 216 Multiple Attempts 218 Completed the process 230 Example of embodiment 232 Link 1 234 Link 2 236 EDCA 238 BA 238a, 238b BA+TF 240 NAV 240a MPDU-1 retransmission 240b MPDU-2 retransmission 242 RTA MPDU retransmission / MBA 244 BA 270 Example of embodiment 276 TF 277 Preamble 278 Special Symbols 280 RTA MPDU-1 282 RTA MPDU-2 284,286 other low priority TIDs 286 Padding 310 Example of embodiment 312 Link 1 314 Link 2 316 PPDU from STA2 317 Preamble 318 Padding 320 DL data to another STA 322 DL data to another STA 324 L1 NAV 326BA2 328 EDCA 330 PPDU from STA1 332 L1 NAV 334BA1 350 Example of embodiment 352 Padding 354 Collision occurred 356 BO 358 PPDU from STA1 360 L1 NAV 362BA1 363 Padding 364 PPDU from STA2 366 L1 NAV 368BA2a 370BA2b 410 Example of embodiment Link 1 for 412 ch2 Link 1 for 414 ch1 416 Link 2 418 Preamble 420 UL Zone Notice 422 ch2 424 ch1 426 Legacy NAV 428 UL Zone 430 Padding 432 DL data to another STA 434 DL data to another STA 436 Preamble Collision 440 PPDU from STA1 444 L1.1 NAV 446 L1.2 NAV 448 Quick Ack 510 Example of embodiment 512 Link 1 514 Link 2 516 TF 518a Preamble 518b Preamble 520 Special Symbols 522 L1 padding 524 RTA MPDU-1 526 RTA MPDU-2 528 BA1+BA2 534 Other low priority TIDs 536 Other low priority TID / RTA MPDU-1 retransmission 538BA1 540 Padding 542 RTA MPDU-2 retransmission 544 Ack / BA2+Low Priority MBA 610 Example of embodiment 612 Link 1 614 Link 2 616TF 618a Preamble 618b Preamble 620,621 UL data from another STA 622 Special Symbols 624,638 S / LTF 626 RTA MPDU-1 628 RTA MPDU-2 630,642 Padding 634,636 Other low priority TIDs 632BA1 640BA2 644 RTA MPDU-1 retransmission 648 RTA MPDU-2 retransmission 650 Example of embodiment 652 Start of reception of long PPDU on the first link 654 Does the preamble or special symbols of the PPDU signal: 1. Use Quick Ack Configuration with Special Symbols 2. Use pre-configured Quick Ack configuration 3. No Quick Ack Required 656 Apply Quick Ack Configuration from Special Symbol 658 Apply QuickAck Config from Pre-configuration 660 Have all configured MPDUs on the first link up to the configured time been received? 662 Should a Quick Ack be Optionally Performed on the Second Link? 664 Quick Ack on the second link 666 Was a Quick Ack or Ack for a Quick Retransmit received? 668 Receives quick retransmission on the first or second link based on configuration 670 First link PPDU finished? 672 Normal Ack / BA on the first link 690 Example of embodiment 692 Start sending long PPDU on the first link 694 Does the preamble or special symbols of the PPDU signal: 1. Use Quick Ack Configuration with Special Symbols 2. Use pre-configured Quick Ack configuration 3. No Quick Ack Required 698 After sending the symbol corresponding to the time when the Quick Ack was configured 700 Was the Quick Ack received? 702 Should it be resent as an Implicit Ack to a Quick Ack? 704 Performs quick retransmission on the first or second link based on the Quick Ack configuration 706 Acknowledge Quick Ack on Second Link 708 First link PPDU finished? 710 Normal Ack / BA received on the first link 730 Example of embodiment 750 Example of embodiment 770 Example of embodiment 790 Example of embodiment 810,830,850 Example of embodiment 870 Example of embodiment 890 Example of embodiment

Claims

1. 1. An apparatus for wireless communication in a network, the apparatus comprising: (a) a wireless communication circuit, the wireless communication circuit operating as a wireless station (STA) in a multi-link device (MLD), as an access point (AP) STA or a non-AP STA, for wirelessly communicating with other wireless stations (STAs) using a carrier sense multiple access with collision avoidance (CSMA / CA) mechanism on a wireless local area network (WLAN) in which enhanced distributed channel access (EDCA) is utilized for random channel access on all links; (b) a processor coupled to the wireless communication circuitry for operating on the WLAN; (c) a non-transitory memory storing instructions executable by said processor for communicating with other STAs; Equipped with (d) the instructions, when executed by the processor, perform steps of a wireless communication protocol for the wireless communication circuit, the steps comprising: (i) transmitting a physical layer protocol data unit (PPDU) including one or more aggregated MAC protocol data units (AMPDUs) on a first link of an originating MLD; (ii) before the initiator completes transmission of the PPDU on the first link, the initiator receives an acknowledgement (Ack) frame as a Quick Ack from the receiving MLD on the second link; (iii) the first and second links to the source MLD and sink MLD are simultaneous transmit / receive (STR) link pairs; Including, An apparatus comprising:

2. 2. The apparatus of claim 1, wherein the originating MLD and the receiving MLD agree on a time instance t0 associated with a Quick Ack agreed upon by the originating and receiving MLDs that corresponds to a set X of MPDUs whose reception status is included in the acknowledgement frame.

3. 3. The apparatus of claim 2, wherein the set X is limited to all MPDUs that were completely transmitted before time t0 for a set of traffic identifiers (TIDs).

4. 3. The apparatus of claim 2, wherein the set X is limited to all MPDUs that were completely transmitted before time t0.

5. 3. The apparatus of claim 2, wherein the acknowledgement frame comprises a block acknowledgement (BA) frame or a multi-STA BA (MBA) frame.

6. 2. The apparatus of claim 1, wherein a long PPDU is transmitted by the originator on the first link while a quick ACK is transmitted by the receiver on the second link, and the receiver can be a TXOP owner on the second link.

7. 2. The apparatus of claim 1, wherein a PPDU is transmitted by the sender on the first link while there is a long PPDU in progress being transmitted by the receiver on the second link.

8. 8. The apparatus of claim 7, further comprising: if the receiver is an AP MLD, allocating a resource unit (RU) as a Shared Ack RU within a long PPDU transmitted by the AP MLD on the second link.

9. A Quick Ack for the PPDU is sent on the first link and is sent in a Shared Ack Resource Unit (RU); Upon successfully receiving the preamble on the first link, when the AP-MLD has not yet received another PPDU on the first link on the same frequency resource, the AP MLD broadcasts a first link NAV for the remaining PPDU duration on the first link plus the NAV of the PPDU, and the identity of the sender of the PPDU is transmitted on the first link; The addressing of the Shared Ack RU can be based on the broadcast AID or on a special AID pre-signaled to the originating non-AP MLD.

2. The device according to claim 1 , characterized in that

10. (a) the NAV and identity information on the Shared Ack RU signals other non-AP MLDs operating on the first link that the first link NAV is busy to avoid a hidden terminal problem on the first link; (b) for an MLD supporting Quick Ack in the Shared Ack RU, RTS / CTS may not be required on the first link; (c) a non-AP MLD transmitting on the first link may observe in the Shared Ack RU whether a first link NAV broadcast indicating that a transmission on the first link to an AP was subject to a collision; 10. The device according to claim 9 .

11. (a) the AP MLD transmits one long PPDU, each having a shared Ack resource unit (RU), on the second link within the same TXOP; (b) the AP MLD sends a control frame UL zone announcement in a legacy duplication format on a channel of the first link; (c) the NAV of the UL zone announcement frame overlaps with the duration of a DL long PPDU within the same TXOP on the second link; 2. The device according to claim 1 , characterized in that

12. (a) the UL zone announcement prevents legacy STAs from accessing the first link within a NAV duration, while a non-AP MLD supporting Shared Ack RU on the second link does not set a NAV; (b) in addition to medium contention / EDCA on a primary channel of the first link, a non-AP MLD supporting Shared Ack RU on the second link initiates an independent medium contention / EDCA on a secondary channel of the first link; (c) performing multiple EDCA accesses on different channels of the same link, thereby avoiding a situation in which a low priority user occupies a primary channel and blocks other high priority users from accessing that channel; (d) during the UL Zone Announcement NAV duration of the first link, an AP is always listening on the primary and secondary channels on the first link, so that a non-AP MLD supporting Shared Ack RU on the second link does not need to take into account the AP's activity on one channel of the first link when accessing another channel of the first link; 12. Apparatus according to claim 11, characterized in that

13. 1. An apparatus for wireless communication in a network, the apparatus comprising: (a) a wireless communication circuit, the wireless communication circuit operating as a wireless station (STA) in a multi-link device (MLD), as an access point (AP) STA or a non-AP STA, for wirelessly communicating with other wireless stations (STAs) using a carrier sense multiple access with collision avoidance (CSMA / CA) mechanism on a wireless local area network (WLAN) in which enhanced distributed channel access (EDCA) is utilized for random channel access on all links; (b) a processor coupled to the wireless communication circuitry for operating on the WLAN; (c) a non-transitory memory storing instructions executable by said processor for communicating with other STAs; Equipped with (d) the instructions, when executed by the processor, perform steps of a wireless communication protocol for the wireless communication circuit, the steps comprising: (i) transmitting a long physical layer protocol data unit (PPDU) including one or more aggregated MAC protocol data units (AMPDUs) on a first link of an originating MLD; (ii) before the initiator completes transmission of the long PPDU on the first link, the initiator receives an acknowledgement (Ack) frame as a Quick Ack from the receiving MLD on the second link; (iii) the first and second links to the source MLD and sink MLD are simultaneous transmit / receive (STR) link pairs; (iv) the originating MLD and the recipient MLD agree on a time instance t0 associated with a Quick Ack agreed upon by the originating and recipient MLDs, which corresponds to a set X of MPDUs whose reception status is included in the acknowledgement frame; Including, An apparatus comprising:

14. 14. The apparatus of claim 13, wherein the set X is limited to all MPDUs that were completely transmitted before time t0 for a set of traffic identifiers (TIDs).

15. 14. The apparatus of claim 13, wherein the set X is limited to all MPDUs that were completely transmitted before time t0.

16. 14. The apparatus of claim 13, wherein the acknowledgement frame comprises a block acknowledgement (BA) frame or a multi-STA (MU) BA frame.

17. 1. A method for performing wireless communication in a network, comprising: (a) performing wireless communication in a wireless station (STA) of a multi-link device (MLD), the wireless station (STA) operating as an access point (AP) STA or a non-AP STA for wirelessly communicating with other wireless stations (STAs) using a carrier sense multiple access with collision avoidance (CSMA / CA) mechanism on a wireless local area network (WLAN) in which enhanced distributed channel access (EDCA) is utilized for random channel access on all links; (b) transmitting a long physical layer protocol data unit (PPDU) including one or more aggregated MAC protocol data units (AMPDUs) on a first link of the originating MLD; (c) before the initiator completes transmission of the long PPDU on the first link, the initiator receives an acknowledgement (Ack) frame as a Quick Ack from the receiving MLD on a second link; (d) the first and second links to the source MLD and sink MLD are simultaneous transmit / receive (STR) link pairs; The method according to claim 1, further comprising:

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