CROSS REFERENCES

[0001] The present Application for Patent claims priority to U.S. Provisional Patent Application No. 62/448,326 to Zhou, et.al., titled "WI-FI MULTICHANNEL

AGGREGATION", filed January 19, 2017; and U.S. Patent Application No. 15/872,825 by Zhou, et al., entitled "MULTI-LINK BLOCK ACKNOWLEDGEMENT MANAGEMENT," filed January 16, 2018; each of which is assigned to the assignee hereof.

BACKGROUND

[0002] The following relates generally to wireless communication, and more specifically to multi-link block acknowledgement (BA) management.

[0003] Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). A wireless network, for example a wireless local area network (WLAN), such as a Wi-Fi (i.e., Institute of Electrical and Electronics Engineers (IEEE) 802.11) network may include an access point (AP) that may communicate with one or more stations (STAs) or mobile devices. The AP may be coupled to a network, such as the Internet, and may enable a mobile device to communicate via the network (or communicate with other devices coupled to the access point). A wireless device may communicate with a network device bi-directionally. For example, in a WLAN, a STA may communicate with an associated AP via downlink and uplink. The downlink (or forward link) may refer to the communication link from the AP to the station, and the uplink (or reverse link) may refer to the communication link from the station to the AP.

[0004] Devices in a WLAN may communicate over unlicensed spectrum, which may be a portion of spectrum that includes frequency bands traditionally used by Wi-Fi technology, such as the 5 GHz band, the 2.4 GHz band, the 60 GHz band, the 3.6 GHz band, and/or the 900 MHz band. The unlicensed spectrum may also include other frequency bands. The wireless connection between an AP and STA may be referred to as a channel or link. Users may access these radio frequency spectrum bands using various contention-based protocols (e.g., as specified by one or more versions of IEEE 802.11). Each band (e.g., the 5 GHz band) may contain multiple channels (e.g., each spanning 20 MHz in frequency), each of which may be usable by an AP or STA. A channel may support multiple connections (e.g., between multiple STAs and the AP) in a multiple access configuration (e.g., code division multiple access (CDMA)). Some wireless communications systems may thus support multi-link aggregation, where transmissions may be transmitted and/or received over two or more links between two wireless devices (e.g., an AP and a STA). Different link quality or transmission performance across different links may result in transmission latency (e.g., due to delays in acknowledgement procedures) and reduced system performance. Improved techniques for multi-link block acknowledgement (BA) management in wireless communications systems supporting multi-link operation may thus be desired.

SUMMARY

[0005] The described techniques relate to improved methods, systems, devices, or apparatuses that support techniques for multichannel block acknowledgements (BAs). For example, a wireless device may establish a BA agreement for the multiple links supported by the wireless device for multi-link aggregation (e.g., a multi-link BA session). A BA agreement may be established based on exchanged multi-link capability information (e.g., a BA window size, one or more wireless link identifiers, etc.). In some cases, a BA agreement may be established across some or all of the multiple links. In other cases, a BA agreement may be established on a per-link basis. For example, a BA agreement may establish a transmitter address (TA), receiver address (RA), and/or traffic identifier (TID) for one or more indicated links. The wireless device may then transmit packets to another wireless device using multiple links, and receive a B A with acknowledgement information accounting for the transmitted packets according to the established BA agreement. The BA agreement may use one, or multiple, of the links to transmit BAs in response to the transmitted packets.

[0006] In cases where the BA agreement is established across multiple links, a transmitting device (e.g., a device transmitting packets or data units and receiving subsequent BAs) may assign each of the data units one of a single set of sequence numbers (SNs) (e.g., a global set of SNs), and the data units may be sent over any of the wireless links. The receiving device (e.g., a device receiving data units and transmitting BAs in response) may receive data units (e.g., associated with a single set of SNs) over any of the multiple links, and transmit a BA in response. In such cases, the established BA agreement may include a longer BA window size (e.g., a multi-link BA window), to accommodate the increased number of packets sent per round-trip-time (e.g., due to multi-link aggregation techniques). A multi-link BA window may, for example, be increased to accommodate the larger single set of SNs necessary for all data units transmitted across the multiple links (e.g., increased from 256 bits to 1024 bits). Therefore, a single scoreboard may be maintained and updated.

[0007] In other cases, the BA agreement is established on a per-link basis and a transmitting device may assign SNs to data units on a per-link basis. That is, The BA agreement may call for both a global set of SNs (e.g., associated with all the links used for multi-link aggregation), as well as a local set of SNs (e.g., associated with each link used for multi-link aggregation). In such cases, data units (e.g., media access control (MAC) protocol data units (MPDUs)) may indicate or carry both a per-link SN as well as a global SN (e.g., in an enhanced MAC header). Data units may then be acknowledged or accounted for on a per- link basis, and mapped to a global scoreboard at the transmitting device. That is, the transmitter may maintain a local scoreboard for each wireless link associated with its own B A agreement, and the local scoreboard may be mapped to a global scoreboard.

[0008] In either case above, a BA window size may be increased to accommodate the increased number of packets communicable in a given period of time due to multi-link operation (e.g., and thus the increased number of SNs needed for BAs). In some cases, the BA window (e.g., the multi-link BA window) may be divided into segments or smaller BA agreements (e.g., covering different portions or ranges of the SNs) for different links. In some examples, a new BA format (e.g., a multi-link BA format) may be defined to indicate a longer bitmap associated with the increased number of SNs (e.g., in cases where a BA agreement is established across multiple links and a single or global set of SNs are used). Alternatively, existing BA formats may be repurposed to implement multi-link BA techniques described herein. For example, a multi-user B A (M-BA) may be repurposed to act as a BA for multiple links for a single user rather than for multiple users. In other examples, single user/single-TID BA formats may be combined or aggregated (e.g., on a single link) to span the increased BA window size.

[0009] A method of wireless communication is described. The method may include establishing a block acknowledgement agreement for a plurality of wireless links used for communications in parallel between the first wireless device and a second wireless device, formatting data to be transmitted to the second wireless device into a plurality of data units, assigning, to each of the plurality of data units, a respective one of a set of sequence numbers common to the plurality of wireless links, transmitting the plurality of data units to the second wireless device over one or more of the plurality of wireless links, and receiving a plurality of block acknowledgements, each of the plurality of block acknowledgements indicating one or more of the set of common sequence numbers.

[0010] An apparatus for wireless communication is described. The apparatus may include means for establishing a block acknowledgement agreement for a plurality of wireless links used for communications in parallel between the first wireless device and a second wireless device, means for formatting data to be transmitted to the second wireless device into a plurality of data units, means for assigning, to each of the plurality of data units, a respective one of a set of sequence numbers common to the plurality of wireless links, means for transmitting the plurality of data units to the second wireless device over one or more of the plurality of wireless links, and means for receiving a plurality of block acknowledgements, each of the plurality of block acknowledgements indicating one or more of the set of common sequence numbers.

[0011] Another apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and

instructions stored in the memory. The instructions may be operable to cause the processor to establish a block acknowledgement agreement for a plurality of wireless links used for communications in parallel between the first wireless device and a second wireless device, format data to be transmitted to the second wireless device into a plurality of data units, assign, to each of the plurality of data units, a respective one of a set of sequence numbers common to the plurality of wireless links, transmit the plurality of data units to the second wireless device over one or more of the plurality of wireless links, and receive a plurality of block acknowledgements, each of the plurality of block acknowledgements indicating one or more of the set of common sequence numbers.

[0012] A non-transitory computer-readable medium for wireless communication is described. The non-transitory computer-readable medium may include instructions operable to cause a processor to establish a block acknowledgement agreement for a plurality of wireless links used for communications in parallel between the first wireless device and a second wireless device, format data to be transmitted to the second wireless device into a plurality of data units, assign, to each of the plurality of data units, a respective one of a set of sequence numbers common to the plurality of wireless links, transmit the plurality of data units to the second wireless device over one or more of the plurality of wireless links, and receive a plurality of block acknowledgements, each of the plurality of block

acknowledgements indicating one or more of the set of common sequence numbers.

[0013] In some examples of the method, apparatus, and non-transitory computer-readable medium described above, transmitting the plurality of data units to the second wireless device over one or more of the plurality of wireless data links further comprises: transmitting a first set of data units of the plurality of data units to the second wireless device over a first wireless link of the plurality of wireless links. Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for transmitting a second set of data units of the plurality of data units to the second wireless device over a second wireless link of the plurality of wireless links.

[0014] In some examples of the method, apparatus, and non-transitory computer-readable medium described above, receiving the plurality of block acknowledgements further comprises: receiving a first set of the plurality of block acknowledgement over the first wireless link, wherein the first set of the plurality of block acknowledgements may be for the first set of the plurality of data units. Some examples of the method, apparatus, and non- transitory computer-readable medium described above may further include processes, features, means, or instructions for receiving a second set of the plurality of block

acknowledgement over the second wireless link, wherein the second set of the plurality of block acknowledgements may be for the second set of the plurality of data units.

[0015] Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for receiving the plurality block acknowledgements over the first wireless link, the plurality of block acknowledgements for both the first set of the plurality of data units and the second set of the plurality of data units.

[0016] In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the received plurality of block acknowledgements further indicate one or more sequence numbers of the second set of sequence numbers for the first set of data units, or one or more sequence numbers of the third set of sequence numbers for the second set of data units, or a combination thereof. [0017] Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for updating, based at least in part on one or more of the plurality of received block

acknowledgments, a scoreboard to track data units acknowledged or not acknowledged by the second wireless device for the plurality of wireless links.

[0018] Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for updating, based at least in part on the received plurality of block acknowledgments, a first scoreboard to track data units acknowledged or not acknowledged by the second wireless device for a first wireless link of the plurality of wireless links, and a second scoreboard to track data units acknowledged or not acknowledged by the second wireless device for a second wireless link of the plurality of wireless links.

[0019] Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for assigning a respective sequence number of a second set of sequence numbers to each of a first set of data units of the plurality of data units to be transmitted over a first wireless link of the plurality of wireless links. Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for assigning a respective sequence number of a third set of sequence numbers to each of a second set of data units of the plurality of data units to be transmitted over a second wireless link of the plurality of wireless links.

[0020] Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for decompressing a block acknowledgement bitmap of the received plurality of block acknowledgements to identify the one or more of the set of common sequence numbers.

[0021] In some examples of the method, apparatus, and non-transitory computer-readable medium described above, a block acknowledgement of the plurality of block

acknowledgements comprises a multi-TID block acknowledgement to acknowledge or not acknowledge a single TID or a single station.

[0022] In some examples of the method, apparatus, and non-transitory computer-readable medium described above, receiving the plurality of block acknowledgements comprises: receiving, in the multi-TID block acknowledgement, a first portion associated with a first starting sequence number and a second portion associated with a second starting sequence number, wherein the first portion and the second portion may be for the single TDD or the single station.

[0023] Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for receiving plurality of block acknowledgements in aggregate span a block acknowledgement window.

[0024] Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for exchanging block acknowledgement capability information with the second wireless device, wherein the block acknowledgement agreement may be established based at least in part on the exchanged block acknowledgement capability information.

[0025] In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the block acknowledgement capability information comprises a block acknowledgement window size, or a wireless link identifier, or a combination thereof.

[0026] Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for determining a first block acknowledgement window size for the plurality of wireless links based at least in part on the exchanged block acknowledgement capability information. Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for establishing a second block acknowledgement window size for a first wireless link of the plurality of wireless links, the second block acknowledgement window size less than the first block acknowledgement window size.

[0027] A method of wireless communication is described. The method may include establishing a block acknowledgement agreement for a plurality of wireless links used for communications in parallel between the first wireless device and a second wireless device, receiving a plurality of data units from the second wireless device over one or more of the plurality of wireless links, each data unit of the plurality of data units associated with one of a set of sequence numbers common to the plurality of wireless links, and transmitting a plurality of block acknowledgements in response to the plurality of data units, each of the plurality of block acknowledgements indicating one or more of the set of common sequence numbers.

[0028] An apparatus for wireless communication is described. The apparatus may include means for establishing a block acknowledgement agreement for a plurality of wireless links used for communications in parallel between the first wireless device and a second wireless device, means for receiving a plurality of data units from the second wireless device over one or more of the plurality of wireless links, each data unit of the plurality of data units associated with one of a set of sequence numbers common to the plurality of wireless links, and means for transmitting a plurality of block acknowledgements in response to the plurality of data units, each of the plurality of block acknowledgements indicating one or more of the set of common sequence numbers.

[0029] Another apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and

instructions stored in the memory. The instructions may be operable to cause the processor to establish a block acknowledgement agreement for a plurality of wireless links used for communications in parallel between the first wireless device and a second wireless device, receive a plurality of data units from the second wireless device over one or more of the plurality of wireless links, each data unit of the plurality of data units associated with one of a set of sequence numbers common to the plurality of wireless links, and transmit a plurality of block acknowledgements in response to the plurality of data units, each of the plurality of block acknowledgements indicating one or more of the set of common sequence numbers.

[0030] A non-transitory computer-readable medium for wireless communication is described. The non-transitory computer-readable medium may include instructions operable to cause a processor to establish a block acknowledgement agreement for a plurality of wireless links used for communications in parallel between the first wireless device and a second wireless device, receive a plurality of data units from the second wireless device over one or more of the plurality of wireless links, each data unit of the plurality of data units associated with one of a set of sequence numbers common to the plurality of wireless links, and transmit a plurality of block acknowledgements in response to the plurality of data units, each of the plurality of block acknowledgements indicating one or more of the set of common sequence numbers. [0031] In some examples of the method, apparatus, and non-transitory computer-readable medium described above, receiving the plurality of data units from the second wireless device over the one or more of the plurality of wireless links further comprises: receiving a first set of a plurality of data units from the wireless device over a first wireless link of the plurality of wireless links, each data unit of the first set associated with one of the set of common sequence numbers. Some examples of the method, apparatus, and non-transitory computer- readable medium described above may further include processes, features, means, or instructions for receiving a second set of the plurality of data units from the wireless device over a second wireless link of the plurality of wireless links, each data unit of the second set associated with one of the set of common sequence numbers.

[0032] In some examples of the method, apparatus, and non-transitory computer-readable medium described above, each of the plurality of block acknowledgements further indicate: one or more of a first set of sequence numbers for the received first set of data units; or one or more of a second set of sequence numbers for the received second set of data units.

[0033] In some examples of the method, apparatus, and non-transitory computer-readable medium described above, transmitting the plurality of block acknowledgements further comprises: transmitting a multi-TID block acknowledgement to acknowledge or not acknowledge a single TDD or a single station, the multi-TID block acknowledgement comprising a first portion associated with a first starting sequence number and a second portion associated with a second starting sequence number, wherein the first portion and the second portion may be for the single TDD or the single station.

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 illustrates an example of a system for wireless communication that supports multi-link block acknowledgement (BA) management in accordance with aspects of the present disclosure.

[0035] FIG. 2 illustrates an example of a wireless communications system that supports multi-link BA management in accordance with aspects of the present disclosure.

[0036] FIGs. 3 through 5 illustrate examples of layer configurations that support multi- link BA management in accordance with aspects of the present disclosure.

[0037] FIGs. 6A and 6B illustrate an example of global-local scoreboard mapping for multi-link BAs in accordance with aspects of the present disclosure. [0038] FIGs. 7 and 8 illustrate examples of process flows that support multi-link BA management in accordance with aspects of the present disclosure.

[0039] FIGs. 9 through 11 show block diagrams of a device that supports multi-link BA management in accordance with aspects of the present disclosure.

[0040] FIG. 12 illustrates a block diagram of a system including a wireless device that supports multi-link BA management in accordance with aspects of the present disclosure.

[0041] FIGs. 13 through 17 illustrate methods for multi-link BA management in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

[0042] Some wireless communications systems may support multiple parallel links between communicating devices, for example, to increase throughput, to improve link efficiency, to reduce latency, etc. A wireless link may refer to a communication path between devices, and each link may support one or more channels (e.g., logical entities) that support multiplexing of data, such that during at least some duration of time, transmissions or portions of transmissions may occur in parallel, for example over both links at the same time, either synchronously, or asynchronously. The wireless links may be in the same or different radio frequency (RF) spectrum bands. Each link of a multi-link session may be associated with respective physical components (e.g., antennas, amplifiers, including power amplifiers and low noise amplifiers, etc.) and/or logical processing components (e.g., physical (PHY) layers, media access control (MAC) layers, etc.) of a given wireless device, and these components may be configured to support multi-link communications. The multiple links may connect wireless devices at the MAC layer (e.g., each link may connect respective lower MAC components of communicating devices). The MAC layer may aggregate data packets from the multiple wireless links to provide to upper layers (if the wireless device is receiving) or receive from upper layers (if the wireless devices is transmitting) of the device (e.g., using multiple connections from the MAC layer to the PHY layer). Such parallel communications, while benefiting the system in terms of throughput and spectral utilization, may increase the complexity of the system.

[0043] Multi-link aggregation may also have implementation challenges. For example, packets may be transmitted and/or received across different links out of order, a given link may suffer degraded communication conditions relative to another of the aggregated links (e.g., frequency-dependent fading, etc.) for some duration of time, a given link or a channel of the link may experience a high traffic volume for some duration of time, etc. which may, for example, result in inefficient block acknowledgement (BA) procedures. Further, increased channel and bandwidth usage, as well as increased peak throughput in a given time period, may result in the need to increase BA windows (e.g., allowed windows or spans of unacknowledged MAC packet data unit (MPDU) sequence numbers (SNs)). In scenarios where multi-link aggregation systems use independent B A procedures for each link, problems may arise at higher layers during aggregation (e.g., when there is a weak or slow link, which may stall a BA window and delay operation of or throttle a second link). Further, sequence numbering and scoreboarding techniques (e.g., techniques for a transmitting device to account for which data units are correctly received as indicated via B As from a receiving device) may need to be modified to account for an increased number of data units being transmitted over the multiple links. As such, wireless communications systems supporting multi-link aggregation may employ multi-link BA management techniques described herein.

[0044] Wireless communications systems capable of multi-link aggregation may require or benefit from improved multi-link BA management techniques. The described techniques relate to improved methods, systems, devices, or apparatuses that support techniques for multichannel or multi-link BAs. For example, a wireless device may establish a BA agreement (e.g., a multi-link BA session) for the multiple links supported by the wireless device for multi-link aggregation. A B A agreement may be established based on exchanged multi-link capability information (e.g., a BA window size, one or more wireless link identifiers, etc.). In some cases, a BA agreement may be established across some or all of the multiple links. In other cases, a BA agreement may be established on a per-link basis.

[0045] In some cases (e.g., for single link operation) each link may be associated with a unique transmitter address (TA), or a unique receiver (RA), or a unique (TID), or a combination of unique TA, RA, and/or TID. For example, for acknowledgment procedures in such cases, a TA, RA, and TID tuple (e.g., <TA, RA, TID>) may correspond to a BA agreement on that particular link. That is, a BA agreement may be set up or established on a per TID basis. For example, an add BA (ADDBA) frame may be per <RA, TA> and per TID (e.g., per access category). However, in some wireless communications systems supporting multi-link operation, each TID may be aggregated across multiple links. Therefore, if each aggregated TID is associated with a common BA agreement across multiple links, predefined mapping between <TA, RA, TID> and the BA agreement may be violated (e.g., in cases where each link keeps a unique <TA, RA>). Thus, a BA agreement may establish a TA, RA, and/or TID for one or more indicated links. The wireless device may then transmit packets to another wireless device using multiple links, and receive a BA with acknowledgement information accounting for the transmitted packets according to the established BA agreement. The BA agreement may use one, or multiple, of the links to transmit BAs in response to the transmitted packets. Further, sequence numbering and scoreboarding techniques may be modified according to the one or more established BA agreements to account for such data units being transmitted over the multiple links, as described in more detail below.

[0046] Aspects of the disclosure are initially described in the context of a wireless communications system. Aspects of the disclosure are then described with reference to example layer configurations as well as example process flow diagrams implementing discussed BA techniques. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to multi- link B A management

[0047] FIG. 1 illustrates a WLAN 100 (also known as a Wi-Fi network) configured in accordance with various aspects of the present disclosure. The WLAN 100 may include an AP 105 and multiple associated STAs 115, which may represent devices such as wireless communication terminals, including mobile stations, phones, personal digital assistant (PDAs), other handheld devices, netbooks, notebook computers, tablet computers, laptops, display devices (e.g., TVs, computer monitors, etc.), printers, etc. The AP 105 and the associated STAs 115 may represent a basic service set (BSS) or an extended service set (ESS). The various STAs 115 in the network are able to communicate with one another through the AP 105. Also shown is a coverage area 110 of the AP 105, which may represent a basic service area (BSA) of the WLAN 100. An extended network station associated with the WLAN 100 may be connected to a wired or wireless distribution system that may allow multiple APs 105 to be connected in an ESS.

[0048] A ST A 115 may be located in the intersection of more than one coverage area 110 and may associate with more than one AP 105. A single AP 105 and an associated set of STAs 115 may be referred to as a BSS. An ESS is a set of connected BSSs. A distribution system may be used to connect APs 105 in an ESS. In some cases, the coverage area 110 of an AP 105 may be divided into sectors. The WLAN 100 may include APs 105 of different types (e.g., metropolitan area, home network, etc.), with varying and overlapping coverage areas 110. Two STAs 115 may also communicate directly via a direct wireless link 125 regardless of whether both STAs 115 are in the same coverage area 110. Examples of direct wireless links 125 may include Wi-Fi Direct connections, Wi-Fi Tunneled Direct Link Setup (TDLS) links, and other group connections. STAs 115 and APs 105 may communicate according to the WLAN radio and baseband protocol for physical and MAC layers from IEEE 802. i l and versions including, but not limited to, 802.11b, 802. l lg, 802.11a, 802.11η, 802.1 lac, 802. Had, 802.11 ah, 802.1 lax, 802. Hay, 802.11ba, etc. In other implementations, peer-to-peer connections or ad hoc networks may be implemented within WLAN 100.

Devices in WLAN 100 may communicate over unlicensed spectrum, which may be a portion of spectrum that includes frequency bands traditionally used by Wi-Fi technology, such as the 5 GHz band, the 2.4 GHz band, the 60 GHz band, the 3.6 GHz band, and/or the 900 MHz band. The unlicensed spectrum may also include other frequency bands.

[0049] In some cases, a STA 115 (or an AP 105) may be detectable by a central AP 105, but not by other STAs 115 in the coverage area 110 of the central AP 105. For example, one STA 115 may be at one end of the coverage area 110 of the central AP 105 while another STA 115 may be at the other end. Thus, both STAs 115 may communicate with the AP 105, but may not receive the transmissions of the other. This may result in colliding transmissions for the two STAs 115 in a contention based environment (e.g., carrier-sense multiple access (CSMA)/collision avoidance (CA)) because the STAs 115 may not refrain from transmitting on top of each other. A STA 115 whose transmissions are not identifiable, but that is within the same coverage area 110 may be known as a hidden node. CSMA/CA may be

supplemented by the exchange of a request-to-send (RTS) packet transmitted by a sending STA 115 (or AP 105) and a clear-to-send (CTS) packet transmitted by the receiving STA 115 (or AP 105). This exchange may alert other devices within range of the sender and receiver not to transmit for the duration of the primary transmission. Thus, RTS/CTS handshake may help mitigate a hidden node problem.

[0050] In a system supporting multi-link aggregation (which may also be referred to as multi-channel aggregation), some of the traffic associated with a single STA 115 may be transmitted across multiple parallel communication links 120 (which may also be referred to as "links" or "wireless links" herein). Multi-link aggregation may thus provide a means to increase network capacity and maximize the utilization of available resources. In some cases, each communication link 120 for a given wireless device may be associated with a respective radio of the wireless device (e.g., where a radio comprises transmit/receive chains, physical antennas, signal processing components, etc.). Multi-link aggregation may be implemented in a number of ways. As a first example, the multi-link aggregation may be packet-based. In packet-based aggregation, frames of a single traffic flow (e.g., all traffic associated with a given TID) may be sent in parallel across multiple communication links 120 (e.g., on multiple channels). In some cases, the multiple communication links 120 may operate in the same RF spectrum band (e.g., each link may be in the 5 GHz band, and use channels in the 5 GHz band). In other cases, the multiple communication links 120 may be in different RF spectrum bands (e.g., one may be in the 2.4 GHz band while another is in the 5 GHz band). Each link may be associated with a different PHY layer and lower MAC layer as described with reference to FIG. 4. In such an implementation, management of the aggregation of the separate communication links 120 may be performed at a higher MAC layer. The multilink aggregation implemented at the lower MAC layers and PHY layers may be transparent to the upper layers of the wireless device.

[0051] As another example, the multi-link aggregation may be flow-based. In flow-based aggregation, each traffic flow (e.g., all traffic associated with a given TID) may be sent using one of multiple available communication links 120. As an example, a single STA 115 may access a web browser while streaming a video in parallel. The traffic associated with the web browser access may be communicated over a first channel of a first communication link 120 while the traffic associated with the video stream may be communicated over a second channel of a second communication link 120 in parallel (e.g., at least some of the data may be transmitted on the first channel concurrent with data transmitted on the second channel). In some examples, the transmissions on the first communication link 120 and the second communication link 120 may be synchronized. In other examples, the transmissions may be asynchronous. As described above, the channels may belong to the same RF band or to different RF bands. In the case of three communication links 120 (e.g., or other numbers of communication links greater than two), all three communication links 120 may support operation over the same RF band (e.g., all three in the 5 GHz RF band). In other cases, two communication links 120, but not the third, may support operation over the same RF band (e.g., two links in the 5 GHz RF band, and one link in the 2.4 GHz RF band). Or, in still other cases each of the three communication links 120 may support operation for a separate RF band. In some cases, flow-based aggregation may not use cross-link packet scheduling and reordering (e.g., which may be used to support packet-based aggregation). Alternatively, in the case of a single flow (e.g., in the case that the STA 115 simply attempts to access a web browser), aggregation gain may not be available.

[0052] In some cases, an AP 105 may designate a given channel or link among communication links 120 as an anchor link (e.g., the wireless link on which it transmits beacons, management frames, control information, association information, etc., to support the discovery, establishment, and/or maintenance of wireless links used for multi-link aggregation, such as during a multi-link session between wireless devices). Although described as being frequency -based, the anchor link could additionally or alternatively be time based, and refer to a point in time. For example, the AP 105 may designate a time period for transmission of control information over one or more links and may employ various techniques to provide improved reliability to the control information in the time interval (e.g., may use a more robust modulation and coding scheme (MCS), may increase a transmission power, etc.). Outside of the time interval, the AP 105 may employ techniques that prioritize data throughput over the one or more links.

[0053] In some examples, one or more of the links (e.g., an anchor link) may operate in a lower RF frequency band than the other links used in the multi-link session. For example, a link may operate in a 2.4 GHz or 900 MHz band to increase the range, power, or signal quality associated with transmissions on another link, relative to other wireless links that may operate at a 5 GHz or 60 GHz band associated with higher data throughputs, but relatively shorter ranges. For example, links in a higher RF band (e.g., the 60 GHz band) may be susceptible to the directionality of the antennas at the communicating devices on both sides of the links. The performance of such links may degrade if either device moves (even slightly). Responsive to such degradations, the devices may perform beam training to realign the link between the devices. During such beam training, the link may be unavailable. In some cases, the 60 GHz link may provide higher throughput (e.g., under certain communication conditions) while the 2.4 GHz link provides a stable link for discovery, link setup, exchange of control and management information, exchange of data traffic (e.g., at a lower data rate than provided by the auxiliary link), etc. Similar techniques may be employed for

technologies other than RF communications such as light communications, which may work over short distances and/or concentrate energy in a small focused beam. Light

communications (e.g., and other similar technologies) may benefit from auxiliary

communications over a secondary link that rely on a reliable anchor link. [0054] In other embodiments, a hybrid of flow-based and packet-based aggregation may be employed. As an example, a device may employ flow-based aggregation in situations in which multiple traffic flows are created and may employ packet-based aggregation in other situations. The decision to switch between multi-link aggregation techniques (e.g., modes) may additionally or alternatively be based on other metrics (e.g., a time of day, traffic load within the network, available battery power for a wireless device, etc.). It is to be understood that while aspects of the preceding are described in the context of a multi-link session involving two (or more) communication links 120, the described concepts may be extended to a multi-link session involving multiple direct wireless links 125.

[0055] To support the described multi-link aggregation techniques, APs 105 and ST As 115 may exchange supported aggregation capability information (e.g. supported aggregation type, supported frequency bands, etc.). In some cases, the exchange of information may occur via a beacon signal, a probe association request or a probe association response, dedicated action frames, an operating mode indicator (OMI), etc. In some cases, an AP 105 may designate a given channel in a given band as an anchor link, and transmit beacons (e.g., which may contain less information) on other channels or links for discovery purposes. The anchor link could additionally or alternatively be time based, and refer to a point in time (e.g., such that an AP 105 may transmit its beacon during a certain time interval on one or more links).

[0056] In some examples, in multi-link aggregation, each link may use its own transmit queue. In other examples, a common transmit queue may be used across the links. In some examples, each link may have a unique TA and RA. In other examples, the TA and RA may be common across the multiple links used for multi-link aggregation. In other examples, one or more of a SN, frame number (FN), and/or packet number (PN) may be common across the communication links. Other items that may be common (or different) across two or more of the links include encryption keys, MPDU generation, aggregated MAC service data unit (AMSDU) constraints, fragment size, reordering, replay check, and/or de-fragmentation techniques. In other examples, encryption keys may be per-link.

[0057] In various examples, BAs may be sent in response to multi-link transmissions. A BA may refer to an acknowledgment (ACK) for multiple MPDUs sent together (e.g., an ACK for a block of MPDUs). The transmitting device (e.g., the device requesting the BA) and the receiving device (e.g., the device transmitting the BA) may establish a BA session (also known as a BA agreement) for during a setup phase, negotiating an agreement regarding the terms and capabilities for the BA session (e.g., using an ADDBA request and response procedure). The transmitting device and receiving device may exchange capability information such as BA size, buffer size, window size (e.g., a sliding window), and/or policy, and then agree on the common parameters for each of the receiving device and the transmitter device to use. The BA agreement may be later torn down (e.g., using a delete BA (DELBA) request).

[0058] Both the transmitting device and the receiving device may maintain a sliding window (e.g., a BA window), and may have previously negotiated the size of the BA. For example, a BA agreement may have a BA size of 64 MPDUs (e.g., other BA size examples may include 256 MPDUs, 1024 MPDUs, etc.). In such cases, a transmitting device may transmit 64 MPDUs followed by a block acknowledgement request (BAR). In response to the BAR, the receiving device may, upon reception of the 64 MPDUs and the BAR, transmit a BA to the transmitting device. The BA may indicate whether all 64 MPDUs were received correctly, which MPDUs are missing, etc. In some cases, a BA may be used to indicate the longer B A window, or a capability exchange or agreement defining the larger BA window may also be sent. In other examples, a single SN may be used, but with multiple scoreboards (e.g., one scoreboard per channel or link), or with a common, global scoreboard as well as per-link scoreboards. Multi-link aggregation (e.g., flow-based and/or packet-based) may increase network capacity by efficiently allocating utilization of multiple links (and multiple channels).

[0059] A block acknowledgment (BA) agreement or a multi-link BA session may be established based on exchanged multi-link capability information. Such multi-link capability information may include one or more of a BA window size, BA scoreboarding information, one or more wireless link identifiers, etc. In some cases, a BA agreement may be established across some or all of the multiple links. In other cases, a BA agreement may be established on a per-link basis. The BA agreement may further establish one or more sets of sequence numbers, as well as scoreboarding techniques used by the transmitting wireless device for the BA session. Sequence numbers may be assigned globally, such that a common set of sequence numbers may be used for MPDUs for all the links. Sequence numbers may also be per-link, with sequence numbers used for each link. A combination of common and per-link sequence numbers may also be used. The wireless device may then transmit packets to another wireless device using the multiple links, and receive a BA with acknowledgement information accounting for the transmitted packets according to the established BA agreement. The BAs may indicate the sequence numbers associated with one or more MPDUs. BAs may then be transmitted on one link or on multiple links by the receiving device.

[0060] FIG. 2 illustrates an example of a WLAN 200 that supports multi-link BA management in accordance with various aspects of the present disclosure. In some examples, WLAN 200 may implement aspects of WLAN 100. A wireless connection between AP 105-a and STA 115-a may be referred to as a link 205 or a communication link, and each link 205 may include one or more channels. As an example, WLAN 200 may support multi-link aggregation such that AP 105-a and STA 115-a may communicate in parallel over two or more links (e.g., link 205-a and link 205-b). STA 115-a may thus receive packets (e.g., MPDUs) over both link 205-a and link 205-b from AP 105-a. Such parallel communications 210-a and 210-b over the two or more links may be synchronized or asynchronous, and may be uplink, or downlink, or a combination of uplink and downlink during a particular duration of time. As described above, the parallel communications 210-a and 210-b over the two or more links 205-a and 205-b may occur between two STAs 115 (e.g., which may be referred to as sidelink communication) without deviating from the scope of the present disclosure.

[0061] Such multi-link aggregation may provide multiple benefits to WLAN 200. For example, multi-link aggregation may improve user-perceived throughput (UPT) (e.g., by quickly flushing per-user transmit queues). Similarly, multi-link aggregation may improve throughput for WLAN 200 by improving utilization of available channels (e.g., by increasing trunking gains). That is, multi-link aggregation may increase spectral utilization and may increase the bandwidth-time product. Networks that do not support multi-link aggregation may experience under-utilization of spectrum in non-uniform (e.g., bursty) traffic conditions. For example the communication load over a given link 205 (e.g., link 205-a) may be low at any particular instant, whereas the demand may be high for another link 205 (e.g., link 205- b). By allowing a single traffic flow (e.g., a single internet protocol (IP) flow) to span across different links 205, the overall network capacity may be increased.

[0062] Further, multi-link aggregation may enable smooth transitions between multi-band radios (e.g., where each radio may be associated with a given RF band) and/or enable a framework to setup separation of control channels and data channels. Other benefits of multi- link aggregation include reducing the ON time of a modem, which may benefit a wireless device in terms of power consumption though the final power-saving gains may in some cases depend on other factors including processing requirements, RF bandwidth, etc. Multi- link aggregation additionally increases multiplexing opportunities in the case of a single BSS. That is, multi-link aggregation may increase the number of users per multiplexed

transmission served by the multi-link AP 105-a.

[0063] In some cases, multi-link aggregation may be supported (including initiated) through signaling between STA 115-a and AP 105-a (or a peer STA 115). As an example, STA 115-a may indicate to AP 105-a (or the peer STA 115) whether it supports multi-link aggregation. For example, STA 115-a may indicate that it supports multi-link aggregation in general, for a particular RF spectrum band, for a link 205 of a given RF spectrum band, etc. Such signaling could be static (e.g., in the form of beacons, probes, association or re- association frames, etc.), semi-static, or dynamic (e.g., via OMI or other similar operational parameters). In some cases, AP 105-a (e.g., or the peer STA 115) may decide whether to aggregate communications with STA 115-a based at least in part on the capabilities advertised by STA 115-a.

[0064] However, multi-link aggregation may also have implementation challenges. For example, packets may be transmitted and/or received across different links out of order, a given link may suffer degraded communication conditions relative to another of the aggregated links (e.g., frequency-dependent fading, etc.) for some duration of time, a given link or a channel of the link may experience a high traffic volume for some duration of time, etc. which may, for example, result in inefficient BA procedures. Further, increased channel and bandwidth usage, as well as increased peak throughput in a given time period, may result in the need to increase BA windows (e.g., allowed windows or spans of unacknowledged MPDU SNs). In scenarios where multi-link aggregation systems use independent BA procedures for each link, problems may arise at higher layers during aggregation (e.g., when there is a weak or slow link, which may stall a BA window and delay operation of or throttle a second link). As such, wireless communications systems supporting multi-link aggregation may employ multi-link B A management techniques described herein.

[0065] Improved multi-link BA management techniques are discussed below. For example, BA agreements, BA formats, transmitting device scoreboarding, etc., may be modified to support improved B A sessions or BA procedures in wireless communications systems capable of multi-link aggregation. A transmitting device and receiving device may exchange capability information such as B A bitmap size, B A buffer size, BA scoreboarding information, BA window size (e.g., a sliding window), and/or policy, and then agree on the common parameters for each of the receiving device and the transmitter device to use. For example, a new BA format may be defined to indicate a longer bitmap which may allow for a larger BA window (e.g., a new multi-link BA window for the multiple links) to be spanned. Further, a transmitting device may maintain a single SN set (e.g., a global SN set) across all links while maintaining a single global scoreboard. Additionally or alternatively, a transmitting device may maintain a global SN set in addition to local SN sets for each link. In such cases, the transmitting device may maintain a local scoreboard for each link. In yet other cases, the transmitting device may maintain a global scoreboard as well as local scoreboards.

[0066] In some example aggregation architectures, all TIDs (e.g., or flow IDs or frame types) may be aggregated over link 205-a and link 205-b (e.g., which may be an example of packet-based aggregation). That is, parallel communications 210-a and 210-b may each have at least one packet having a common TDD. Packet-based aggregation may provide

improvements in UPT and total throughput (e.g., even for the case of a single traffic flow). In some cases, links 205-a and 205-b may have independent PHY and lower MAC operations (e.g., CSMA) while aggregation is performed at an upper MAC layer (e.g., as described further below, with reference to FIGs. 3 through 5).

[0067] In cases where a single SN set is used across all links (e.g., a global SN set), a single scoreboard may be maintained. That is, the SN set and scoreboard used by the transmitting device may be common across all the links or channels. In such cases, BA procedures may be performed across all links (e.g., not on an individual, per-link basis). In such cases, a new B A format may be defined to indicate a longer bitmap, which may allow a new maximum BA window to be spanned. For example, in wireless communications systems supporting three link aggregation, three times as many packets may be communicated in a given round trip time. As such, the new BA format supporting the longer bit map may be used to acknowledge the additional packets, as B A window typical of single link systems may be too short given the increased number of packets to account for. A BA frame format may also allow for compression methods (e.g., TFM compression mechanisms) that may be used to reduce the BA bitmap length actually sent over the air. The BA may be sent by a receiving device on any channel or, in some cases, on a designated channel (e.g., a control channel). Alternative to using a new BA format, multi user BAs (M-B As) may be repurposed for multiple links or channels associated with one receiving device. Each per-TID or per-STA portion of the M-BA may be repurposed to acknowledge a same STA/TID, but with a different starting SN. The repurposed M-BA may be sent by the receiving device on any of the channels or, in some cases, only on a designated channel (e.g., a control channel). Further, single user (SU)/single-TID BA formats may be repurposed for multi-link BA management techniques. A receiving device may send multiple SU/single-TID BAs in order to span the extended multi-link BA window. The multiple SU/single-TID BAs may be sent on a same channel (e.g., a designated channel) or may be sent individually on any of the channels.

[0068] In some examples, a single BA agreement may be defined across all links or bands. The BA agreement may indicate a longer BA window (e.g., a multi-link BA window). In such examples, any SN may be sent on any channel and may acknowledged in any manner as discussed above. In other examples, a capability exchange/agreement may define the larger BA window (e.g., a multi-link BA window). Additionally, multiple existing BA agreements may be setup on shorter BA windows. For example, a transmitter and receiver may agree to use a 1024 bit BA window, but then setup four 256 bit BA agreements, each of the BA agreements may be used (e.g., at the discretion of the transmitting device) to cover different portions of the SN, subject to the overall BA window limitation. The multiple agreements may be used to artificially enable the use of multiple BAs to expand the equivalent B A bitmap. An indicator (e.g., a TID-link indicator) may be used to distinguish between the multiple agreements. That is, multiple BA agreements may be reused or repurposed on the same SN to enable a larger overall BA window.

[0069] In some cases, a transmitting device may use a single SN set across all bands or links, however multiple scoreboards may be maintained (e.g., one for each link). Each BA agreement, as well as each B A scoreboard, may be tied to a channel or link. Therefore, each interference may reuse existing per-channel MAC and BA scoreboarding procedures with minimal or zero change. A limitation may be established that keeps the SN within the overall BA window. A BA agreement per-link may be instantiated, and a capability or agreement for the overall BA window may be in place.

[0070] Further, additional SN sets may be used (e.g., on a per-link basis) in addition to a global SN set. In such cases, both a global scoreboard as well as per-link scoreboards may be maintained by a transmitting device. MPDUs may thus carry both a per-link SN as well as a global SN (e.g., which may both be carried in a multi-link or enhanced MAC header). On each link, BAs may be used to acknowledge MPDUs based on the per-link SN. Scoreboarding may be maintained on a per-link basis (e.g., acting on the per-link SN, instead of the global SN) and single link BA mechanisms may be reused. A BA agreement per-link may be setup to define the allowed window of per-link SN, which may be of limited size. A management layer common across all links may map the per-link scoreboard with the global scoreboard based on a global SN set. Additionally, the receiving device may use the global SN for reordering. In such cases, existing BA formats may be used for each individual link. Such implementation details discussed above are now described in more detail below with reference to FIGs. 3 through 8.

[0071] In some examples, some links 205 may be reserved for uplink only or downlink only communication (e.g., link 205-a may be a downlink directional link and link 205-b may be an uplink directional link). In such examples STA 115-a may receive downlink

communications via links supporting downlink communications (e.g., including link 205-a), and may pass ACK information (e.g., received SNs) to other lower MAC entities (e.g., associated with link 205-b) which may accumulate and transmit the associated BAs to the transmitting device (e.g., AP 105-a). Therefore, link 205-b may transmit BAs associated with the downlink data. In some cases, the receiving device may not manage a separate upper MAC entity for BA management purposes. By analogy, AP 105-a may accumulate and manage SNs via link 205-b.

[0072] Similar techniques may be employed for technologies other than RF

communications, such as light communications, which may work over short distances and/or concentrate energy in a small focused beam and/or may support a wireless link that may communicate between wireless devices in only one direction (e.g., only uplink, or only downlink, or only one direction between peer devices). Light communications (e.g., visible light communication (VLC)) and other similar technologies may benefit from auxiliary communications over a secondary link that rely on a reliable anchor link. For example, light communication (or similar communications) may be transmitted from an overhead light to a wireless device (e.g., downlink communication using a light emitting diode (LED) lamp, etc., to a mobile device) but may not support uplink communication from the wireless device to the overhead light (e.g. the LED lamp may be able to receive RF transmissions, but not VLC transmissions). Such communications may benefit from an anchor link (e.g., a 2.4 GHz link or 5 GHz link), which serves as the uplink (reverse link) to the downlink light

communications. For example, the anchor link may carry acknowledgements, including block acknowledgements, on the uplink in response to the data transmitted by the overhead light on the downlink. In other examples, the anchor link may carry scheduling information, etc., for the transmissions using light communication from the overhead light.

[0073] As discussed above, unidirectional communications (e.g., VLC communications) where a reverse link may be absent or where a link in one direction may be unreliable or intermittent, another link (e.g., a Wi-Fi link) may serve as the reverse link for response frames (e.g., such as ACKs or block ACKs for the unidirectional communications). In such scenarios, a common queue (e.g., a common or global scoreboard) may be used such that ACKs may be received on any suitable links, and ACK scoreboarding may not necessarily be performed on a per-link basis.

[0074] Further, some links in a wireless communications system supporting multi-link aggregation may be stronger or more stable than others. In some cases, such links may be identified via BA procedures contemplated herein. In cases where weak links or more stable links are identified, stable links may be selected for BA transmission, discovery, link setup, exchange of control and management information, exchange of data traffic (e.g., at a lower data rate than provided by the auxiliary link), etc., while the weaker or less stable link may be reserved for data transmissions (e.g., high-throughput data transmissions).

[0075] FIG. 3 illustrates an example of a layer configuration 300 that supports multi-link BA management in accordance with various aspects of the present disclosure. In some examples, layer configuration 300 may implement aspects of WLAN 100 and/or WLAN 200. Layer configuration 300 may apply to a STA 115 or an AP 105, and be for a transmitting wireless device or a receiving wireless device. It is to be understood that aspects of layer configuration 300 may represent logical constructs (e.g., such that components of layer configuration 300 may share hardware components). A wireless device may support layer configuration 300 through the use of various hardware configurations described herein.

[0076] As illustrated, layer configuration 300 may include upper layers 305, a MAC layer 310, and one or more PHY layers 335 (e.g., where each PHY layer 335 may in some cases be associated with a respective link or channel). MAC layer 310 may be further divided into upper MAC layer 315 and lower MAC layer 325-a, lower MAC layer 325-b, and lower MAC layer 325-c. While three lower MAC layers 325 are illustrated, it is to be understood that upper MAC layer 315 may control (e.g., via multi-link aggregation controller 320) any suitable number of lower MAC layers 325. Signaling between a given lower MAC (e.g., lower MAC layer 325-a) and upper MAC layer 315 may be carried by connection 345. Similarly, signaling between lower MAC layer 325-a and PHY layer 335-a may be carried by connection 350 and signaling between lower MAC layer 325-a and lower MAC layer 325-b may be carried by connection 340. As described below, the signaling for lower MAC 325-a, lower MAC layer 325-b, and lower MAC layer 325-c may be based on logic associated with respective controller 330-a, controller 330-b, and controller 330-c.

[0077] With reference to FIG. 2, lower MAC layer 325-a may be associated, for example, with link 205-a (e.g., via PHY layer 335-a) and lower MAC layer 325-b may be associated, for example, with link 205-b (e.g., via PHY layer 335-b). That is, each link 205 may have an associated lower MAC layer 325 that performs link-specific features (e.g., channel access, UL triggered transmission procedures, multiple-input, multiple-output (MFMO) signaling, etc.) For example, lower MAC layer 325-a and lower MAC layer 325-b may independently perform enhanced distributed channel access (EDCA) countdowns on respective links 205-a and 205-b. Additionally or alternatively, lower MAC layers 325 may perform RTS/CTS procedures, perform clear channel assessment (CCA) procedures, apply a modulation and coding scheme (MCS), control a physical packet data unit (PPDU) duration, transmit sounding reference signals, etc.

[0078] Upper MAC layer 315 may provide a single-link interface to upper layers 305. For example, upper MAC layer 315 may perform management and security-related operations. Such a design may allow a single beacon from an AP 105 on a primary band to control multi- band STAs 115. Additionally or alternatively, the single upper MAC layer 315 may allow for a single association procedure to initiate the multi-link session. For example, an association procedure may be performed using a single link, but provide for capability information for multiple links, which may include the link that is being used for the association procedure. In some cases, the upper MAC layer 315 may provide signaling (e.g., OMI signaling) that allows for dynamic bandwidth control (e.g., expansion). The upper MAC layer 315 may additionally or alternatively provide a single BA space (e.g., a single BA scoreboard and sequence space) such that MPDUs may be scheduled dynamically on a per-PPDU basis for each link (e.g., such that a given MPDU may be retransmitted on a different link from that on which it was originally transmitted).

[0079] FIG. 3 may illustrate single or global scoreboard management for multi-link BA procedures. For example, upper MAC layer 315 may handle processing and management of SNs identified in BAs received via one or more lower MAC layers 325. That is, upper MAC layer 315 may update a scoreboard 355 to identify which MPDUs have been successfully received as well as identify which MPDUs have been unsuccessfully received. Scoreboard 355 may be associated with a global set of SNs. In some cases, the SN set associated with scoreboard 355 may be divided into different portions or different ranges of the set of SNs, and each portion or range of the set of SNs may be associated with the different links used for transmission of the MPDUs. Thus each link may be associated with a particular range of the global set of SNs, and BAs associated with such ranges may be aggregated at scoreboard 355 such that the transmitting device may account for data units successfully or unsuccessfully transmitted to the receiving device. In other cases (e.g., for VLC or other unidirectional communications), a global scoreboard may be used such that some links may be used for unidirectional communications, while other links may be used as the reverse link (e.g., for response frames) for such unidirectional links. For example, a global scoreboard 555-a may be used to account for unidirectional communications sent via Link 1, by managing ACKs received via Link 2. In such an example, a global set of SNs may be used for unidirectional Link 1 communications, and ACKs corresponding to SNs used for such unidirectional communications may be received over other links (e.g., Link 2, etc.) and accounted for (e.g., by the multi-link aggregation controller 320).

[0080] In some examples, the transmitting device may use information of scoreboard 355 to identify links performing strongly (e.g., by identifying per-link SN ranges of scoreboard 355 associated with several successful transmissions) and/or links performing weakly (e.g., by identifying per-link SN ranges of scoreboard 355 associated with several unsuccessful transmissions).

[0081] FIG. 4 illustrates an example of a layer configuration 400 that supports multi-link BA management in accordance with various aspects of the present disclosure. In some examples, layer configuration 400 may implement aspects of WLAN 100 and/or WLAN 200. Layer configuration 400 may apply to a STA 115 or an AP 105, and be for a transmitting wireless device or a receiving wireless device. It is to be understood that aspects of layer configuration 400 may represent logical constructs (e.g., such that components of layer configuration 400 may share hardware components). A wireless device may support layer configuration 400 through the use of various hardware configurations described herein.

[0082] As illustrated, layer configuration 400 may include upper layers 405, a MAC layer 410, and one or more PHY layers 435 (e.g., where each PHY layer 435 may in some cases be associated with a respective link or channel). MAC layer 410 may be further divided into upper MAC layer 415 and lower MAC layer 425-a, lower MAC layer 425-b, and lower MAC layer 425-c. While three lower MAC layers 425 are illustrated, it is to be understood that upper MAC layer 415 may control (e.g., via multi-link aggregation controller 420) any suitable number of lower MAC layers 425. Signaling between a given lower MAC (e.g., lower MAC layer 425-a) and upper MAC layer 415 may be carried by connection 445.

Similarly, signaling between lower MAC layer 425-a and PHY layer 435-a may be carried by connection 450 and signaling between lower MAC layer 425-a and lower MAC layer 425-b may be carried by connection 440. As described below, the signaling for lower MAC 425-a, lower MAC layer 425-b, and lower MAC layer 425-c may be based on logic associated with respective controller 430-a, controller 430-b, and controller 430-c.

[0083] With reference to FIG. 2, lower MAC layer 425-a may be associated, for example, with link 205-a (e.g., via PHY layer 435-a) and lower MAC layer 425-b may be associated, for example, with link 205-b (e.g., via PHY layer 435-b). That is, each link 205 may have an associated lower MAC layer 425 that performs link-specific features (e.g., channel access, UL triggered transmission procedures, multiple-input, multiple-output (MFMO) signaling, etc.) For example, lower MAC layer 425-a and lower MAC layer 425-b may independently perform enhanced distributed channel access (EDCA) countdowns on respective links 205-a and 205-b. Additionally or alternatively, lower MAC layers 425 may perform RTS/CTS procedures, perform clear channel assessment (CCA) procedures, apply a modulation and coding scheme (MCS), control a physical packet data unit (PPDU) duration, transmit sounding reference signals, etc.

[0084] Upper MAC layer 415 may provide a single-link interface to upper layers 405. For example, upper MAC layer 415 may perform management and security-related operations. Such a design may allow a single beacon from an AP 105 on a primary band to control multi- band STAs 115. Additionally or alternatively, the single upper MAC layer 415 may allow for a single association procedure to initiate the multi-link session. For example, an association procedure may be performed using a single link, but provide for capability information for multiple links, which may include the link that is being used for the association procedure. In some cases, the upper MAC layer 415 may provide signaling (e.g., OMI signaling) that allows for dynamic bandwidth control (e.g., expansion). The upper MAC layer 415 may additionally or alternatively provide a single BA space (e.g., a single BA scoreboard and sequence space) such that MPDUs may be scheduled dynamically on a per-PPDU basis for each link (e.g., such that a given MPDU may be retransmitted on a different link from that on which it was originally transmitted).

[0085] FIG. 4 may illustrate per-link (e.g., local) scoreboard management for multi-link BA procedures. For example, lower MAC layers 425 may handle processing and

management of SNs identified in per-link BAs received. That is, each lower MAC layer 425 may update a scoreboard 455 to identify which MPDUs have been successfully received as well as identify which MPDUs have been unsuccessfully received. Each scoreboard 455 may be associated with a per-link set of SNs. In some examples, the transmitting device may use information of each scoreboard 455 to identify links performing strongly (e.g., by identifying scoreboards 455 indicating many successful MPDU transmissions) and/or links performing weak (e.g., by identifying scoreboards 455 indicating a few or several unsuccessful MPDU transmissions). In such cases, a receiving device (e.g., a STA receiving multi-link

communications via layer configuration 400) may not necessarily maintain or manage a separate upper MAC layer 415 or an upper MAC entity, as the receiving device may not maintain a common or global scoreboard for BAs.

[0086] In some examples, some links may be reserved for uplink only or downlink only communication (e.g., Link 1 may be a downlink directional link and Link 2 may be an uplink directional link). In cases where a receiving device is receiving multi-link communications via layer configuration 400, the receiving device may, for example, receive multi-link downlink communications via links supporting downlink communications (e.g., including Link 1), and may pass ACK information (e.g., received SNs may be passed via connections 440) to lower MAC entity 425-b (e.g., Link 2) which may accumulate and transmit the associated BAs to the transmitting device. Therefore, Link 2 may transmit BAs associated with the multi-link downlink data (e.g., the receiving device may not manage a separate upper MAC 415). By analogy, transmitting devices may accumulate and manage SNs via link 2.

[0087] FIG. 5 illustrates an example of a layer configuration 500 that supports multi-link BA management in accordance with various aspects of the present disclosure. In some examples, layer configuration 500 may implement aspects of WLAN 100 and/or WLAN 200. Layer configuration 500 may apply to a STA 115 or an AP 105, and be for a transmitting wireless device or a receiving wireless device. It is to be understood that aspects of layer configuration 500 may represent logical constructs (e.g., such that components of layer configuration 500 may share hardware components). A wireless device may support layer configuration 500 through the use of various hardware configurations described herein.

[0088] As illustrated, layer configuration 500 may include upper layers 505, a MAC layer 510, and one or more PHY layers 535 (e.g., where each PHY layer 535 may in some cases be associated with a respective link or channel). MAC layer 510 may be further divided into upper MAC layer 515 and lower MAC layer 525-a, lower MAC layer 525-b, and lower MAC layer 525-c. While three lower MAC layers 525 are illustrated, it is to be understood that upper MAC layer 515 may control (e.g., via multi-link aggregation controller 520) any suitable number of lower MAC layers 525. Signaling between a given lower MAC (e.g., lower MAC layer 525-a) and upper MAC layer 515 may be carried by connection 545.

Similarly, signaling between lower MAC layer 525-a and PHY layer 535-a may be carried by connection 550 and signaling between lower MAC layer 525-a and lower MAC layer 525-b may be carried by connection 540. As described below, the signaling for lower MAC 525-a, lower MAC layer 525-b, and lower MAC layer 525-c may be based on logic associated with respective controller 530-a, controller 530-b, and controller 530-c.

[0089] With reference to FIG. 2, lower MAC layer 525-a may be associated, for example, with link 205-a (e.g., via PHY layer 535-a) and lower MAC layer 525-b may be associated, for example, with link 205-b (e.g., via PHY layer 535-b). That is, each link 205 may have an associated lower MAC layer 525 that performs link-specific features (e.g., channel access, UL triggered transmission procedures, multiple-input, multiple-output (MFMO) signaling, etc.) For example, lower MAC layer 525-a and lower MAC layer 525-b may independently perform enhanced distributed channel access (EDCA) countdowns on respective links 205-a and 205-b. Additionally or alternatively, lower MAC layers 525 may perform RTS/CTS procedures, perform clear channel assessment (CCA) procedures, apply a modulation and coding scheme (MCS), control a physical packet data unit (PPDU) duration, transmit sounding reference signals, etc.

[0090] Upper MAC layer 515 may provide a single-link interface to upper layers 505. For example, upper MAC layer 515 may perform management and security-related operations. Such a design may allow a single beacon from an AP 105 on a primary band to control multi- band STAs 115. Additionally or alternatively, the single upper MAC layer 515 may allow for a single association procedure to initiate the multi-link session. For example, an association procedure may be performed using a single link, but provide for capability information for multiple links, which may include the link that is being used for the association procedure. In some cases, the upper MAC layer 515 may provide signaling (e.g., OMI signaling) that allows for dynamic bandwidth control (e.g., expansion). The upper MAC layer 515 may additionally or alternatively provide a single BA space (e.g., a single BA scoreboard and sequence space) such that MPDUs may be scheduled dynamically on a per-PPDU basis for each link (e.g., such that a given MPDU may be retransmitted on a different link from that on which it was originally transmitted).

[0091] FIG. 5 may illustrate both global scoreboard and per-link scoreboard management for multi-link BA procedures. For example, upper MAC layer 515 may handle processing and management of SNs identified in BAs received via one or more lower MAC layers 525. That is, upper MAC layer 515 may update a global scoreboard 555-a to identify which MPDUs have been successfully received as well as identify which MPDUs have been unsuccessfully received. Scoreboard 555-a may be associated with a global set of SNs.

Additionally, lower MAC layers 525 may handle processing and management of SNs identified in per-link BAs received. That is, each lower MAC layer 525 may update a scoreboard 555 (e.g., scoreboard 555-b, scoreboard 555-c, and scoreboard 555-d) to identify which MPDUs have been successfully received as well as identify which MPDUs have been unsuccessfully received. Scoreboard 555-b, scoreboard 555-c, and scoreboard 555-d may be associated with a local or per-link set of SNs (e.g., a set of SNs for Link 1, Link 2, and so on to Link N respectively). In some examples, the transmitting device may use information of each per-link scoreboards 555 to identify links performing strongly (e.g., by identifying per- link scoreboards 555 indicating many successful MPDU transmissions) and/or links performing weakly (e.g., by identifying per-link scoreboards 555 indicating a few or several unsuccessful MPDU transmissions). Further, a transmitting device may map per-link scoreboards 555-b, 555-c, and 555-d to global scoreboard 555-a in order to determine which transmitted MPDUs were successfully and/or unsuccessfully received on a global level (e.g., as opposed to a per-link level), as discussed in more detail below.

[0092] FIG. 6A illustrates an example of a multi-link transmission 600 and FIG. 6B illustrates an example of global-local scoreboard mapping 601 that supports multi-link BA management in accordance with various aspects of the present disclosure. In some examples, multi-link transmission 600 and global-local scoreboard mapping 601 may implement aspects of WLAN 100 and/or WLAN 200. [0093] As discussed above, a transmitting device may map per-link scoreboards to a global scoreboard in order to determine which transmitted MPDUs were successfully and/or unsuccessfully received on a global level. That is, MPDUs may either be associated with both a local (e.g., per-link) SN as well as a global SN or, in other cases, the MPDUs may be associated with either a local SN or a global SN. In cases where each MPDU is associated with both a local SN and a global SN, or in cases where each MPDU is only associated with a global SN, such local scoreboard to global scoreboard mapping may not be necessary, as the global SN is already included. However, in cases where MPDUs are only associated with a local SN, such a mapping may be performed.

[0094] In cases where a single BA agreement is established across two or more links associated with multi-link operation between a transmitting device and a receiving device, data units or packets (e.g., MPDUs) associated with sequential SNs may be sent on any link. The transmitting device may sequentially number the data units according to a single set of SNs (e.g., a global set of SNs), which may then be transmitted to wireless device 805-b via the one or more links. As such, a multi-link BA window size (e.g., a longer BA window) may be used as discussed above. The subsequent BAs may be associated with a BA format the allows for an extended bit map to compensate for the increased number of SNs associated with received, or not received, MPDUs (e.g., at the receiving device). The transmitting device may then update a global scoreboard based on the received BAs.

[0095] In cases where a BA agreement is established per-link, each link may, in some cases, be associated with a per-link (local) set of SNs. In such cases, each data unit may be associated with both a global SN as well as a local SN. The additional information (e.g., associated with the additional SN) may be conveyed in the MPDU via, for example, and extended MAC header. Again, as a global SN is included, the BAs may be mapped directly to a global scoreboard.

[0096] However, in some scenarios, as illustrated in FIG. 6, transmitted MPDUs may only be associated with local SNs. In such cases, both a global scoreboard and per-link scoreboards (e.g., as described in more detail with reference to FIG. 5) may be maintained. FIG. 6A shows an example multi-link transmission 600. Each number of FIG. 6 A may illustrate a global MPDU number, even though MPDUs on each link may be associated with SNs ordered sequentially. FIG. 6B shows an example scoreboard mapping 601 that further illustrates the corresponding per-link SNs for MPDUs of example multi-link transmission 600. For example, a third MPDU to be transmitted by a transmitting device is illustrated as ' 3 ' on Link 2 in FIG. 6 A and may correspond with the Link 2 SN value of Ί ' in FIG. 6B, as the third global MPDU (Global SN value of '3') is the first MPDU transmitted on 'Link 2.'

[0097] As an example, each MPDU may be associated with one or more BAs. As shown in FIG. 6A, MPDU 4 (e.g., MPDU associated with Link 2 SN value of '2') and MPDU 5 (e.g., MPDU associated with Link 2 SN value of '2', having Global SN value of '5') may be unsuccessfully transmitted. FIG. 6B illustrates local or per-link scoreboard mapping to the global scoreboard mapping. For example, an MPDU with a local SN of '2' may be indicated as unsuccessfully received on Link 2 via a B A. The transmitting device may map the value to a global scoreboard, and identify the fourth transmitted MPDU (e.g., MPDU associated with global SN value of '4') was unsuccessfully transmitted. As such, the transmitting device may transmit the fourth MPDU on another link (e.g., 'Link ). Further, the retransmitted MPDU with a local SN of '3' may be indicated as successfully received on Link 1 via a BA. The transmitting device may map the value to a global scoreboard, and identify the fourth transmitted MPDU (e.g., MPDU associated with global SN '4') was successfully

retransmitted.

[0098] FIG. 7 illustrates an example of a process flow 700 that supports multi-link BA management in accordance with various aspects of the present disclosure. In some examples, process flow 700 may implement aspects of WLAN 100 and/or WLAN 200. Process flow 700 may include a wireless device 705-a (e.g., a transmitting device) and a wireless device 705-b (e.g., a receiving device), each of which may represent a STA 115 and/or an AP 105 as described with reference to FIGs. 1 and 2.

[0099] At 710, wireless device 705-a may establish a BA agreement (which may include multiple BA agreements on a per-link basis) with wireless device 705-b. In some cases, establishing a BA agreement may include exchanging BA capability information. BA capability information may include a BA window size, a wireless link identifier, etc. For example, establishing a BA agreement may include defining or indicating a longer BA window (e.g., a 1024 bit BA window). Such a longer BA window for multi-link BAs may allow for improved BA procedures due to the increased number of packets that may be received in a given time period due to multi-link operation. In some cases, a BA agreement may be established across multiple bands or links (e.g., via wireless link identifiers). In other cases, as described in more detail above, a BA agreement may be established on a per-link basis.

[0100] At 715, wireless device 705-a may format data to be transmitted to wireless device 705-b into one or more data units. For example, data from an upper layer (e.g., an application layer, etc.) may be formatted into MPDUs (e.g., at the upper MAC layer).

[0101] At 720, wireless device 705-a may assign SNs to the one or more data units. The SNs may be assigned to the data units in accordance with one or more B A agreements established at 710. That is, whether a global set of SNs are applied to the data units, or different sets of SNs are applied to data units depending on which lower MAC layer entity or link will be used to transmit the data units, may be determined based at least in part on the BA agreement established.

[0102] At 725, the wireless device 705-a may transmit the data units to wireless device 705-b via multiple links and multiple MAC entities. For example, a first set of data units may be transmitted over a first wireless link, and a second set of data units may be transmitted over a second wireless link. As discussed above, at 720, the first and second set of data units may be associated with a single set of global SNs or, in other cases, may be associated with a per-link (local) set of SNs, or may be associated with both global SNs and per-link SNs.

[0103] At 730, wireless device 705-b may transmit one or more BAs in response to the transmissions received at 725. The one or more BAs may indicate SNs associated with data units (e.g., MPDUs) that were successfully received (e.g., via a BA bitmap). For example, at 730, wireless device 705-a may decompress a BA bitmap of the one or more BAs

(transmitted by wireless device 705-b) to identify SNs of data units (transmitted by wireless device 705-a at 725) that were correctly received. In some cases, BAs may include a multi- TID BA to acknowledge or not acknowledge a single TID or a single station. In such cases, wireless device 705-a may further receive (e.g., in the multi-TID BA) a first portion of the single TID or the single station (e.g., starting with a first starting SN) and a second portion of the single TID or the single station (e.g., starting with a second starting SN). The one or more BAs may, in aggregate, span a BA window (e.g., established at 710).

[0104] In some examples, the BAs received by wireless device 705-a at 730 may be received over one (e.g., a first) wireless link and the BAs may be associated with data units sent, by the wireless device 705-a at 725, over both the first and second wireless links. In other examples, wireless device 705-a may receive a first set of BAs over the first link for data units sent, by the wireless device 705-a at 725, over the first link, and receive a second set of BAs over the second link for data units sent, by the wireless device 705-a at 725, over the second link. That is, BAs at 730 may be sent over a single link for data units sent over multiple links or may be sent over the respective links over which the data units were sent (e.g., which may be determined or established at 710). In other cases, BAs at 730 may be sent over multiple links for data units sent over multiple links (which may be a different set of multiple links than for transmission of the data units, where some or all of the links may be different).

[0105] FIG. 8 illustrates an example of a process flow 800 that supports multi-link BA management in accordance with various aspects of the present disclosure. In some examples, process flow 800 may implement aspects of WLAN 100 and/or WLAN 200. Process flow 800 may include a wireless device 805-a and a wireless device 805-b, each of which may represent a STA 115 and/or an AP 105 as described with reference to FIGs. 1 and 2.

[0106] At 810, wireless device 805-a and wireless device 805-b may exchange BA capability information. BA capability information may include a BA window size, a wireless link identifier, etc. In some cases, a first B A window size for the multiple wireless links may be determined based on the exchanged B A capability information. Additionally, in some cases, a second BA window size may be established for one or more of the multiple wireless links, where the second BA window size is less than the first BA window size.

[0107] At 815, wireless device 805-a may establish a BA agreement with wireless device 805-b (e.g., based on BA capability information exchanged at 810). For example, establishing a BA agreement may include defining a BA agreement across bands or links (e.g., via wireless link identifiers), and may further indicate or define a longer BA window (e.g., a 1024 bit BA window). In some cases, the BA agreement may further define the multi-link BA window. In some examples, the larger overall BA window may be further defined or divided into multiple existing agreements on shorter BA windows. For example, the wireless device 805-a and the wireless device 805-b may agree to use a 1024 bit BA window, and additionally set up four 256 bit BA agreements, each of which may be used (e.g., at the discretion of wireless device 805-a) to cover different portions of the SN, subject to the overall B A window limitation. Such a longer BA window for multi-link BAs may allow for improved BA procedures due to the increased number of packets that may be received in a given time period due to multi-link operation. In other cases, as described in more detail above, a BA agreement may be established on a per-link basis.

[0108] At 820, wireless device 805-a may format data to be transmitted to wireless device 805-b into one or more data units. For example, data from an upper layer (e.g., an application layer, etc.) may be formatted into MPDUs (e.g., at the upper MAC layer).

[0109] At 825, wireless device 805-a may assign SNs to the one or more data units. The SNs may be assigned to the data units in accordance with one or more BA agreements established at 815. That is, whether a global set of SNs are applied to the data units, or different sets of SNs are applied to data units depending on which lower MAC layer entity or link will be used to transmit the data units, may be determined based at least in part on the BA agreement established.

[0110] At 830, the wireless device 805-a may transmit the data units to wireless device 805-b via multiple links and multiple MAC entities. For example, a first set of data units may be transmitted over a first wireless link, and a second set of data units may be transmitted over a second wireless link. As discussed above, at 825, the first and second set of data units may be associated with a single set of global SNs or, in other cases, may be associated with a per-link (local) set of SNs, or may be associated with both global SNs and per-link SNs.

[0111] At 835, wireless device 805-b may transmit one or more BAs in response to the transmissions received at 830. The one or more BAs may indicate SNs associated with data units (e.g., MPDUs) that were successfully received (e.g., via a BA bitmap). For example, at 835, wireless device 805-a may decompress a BA bitmap of the one or more BAs

(transmitted by wireless device 805-b) to identify SNs of data units (transmitted by wireless device 805-a at 830) that were correctly received. In some cases, BAs may include a multi- TID BA to acknowledge or not acknowledge a single TID or a single station. In such cases, wireless device 805-a may further receive (e.g., in the multi-TID BA) a first portion of the single TID or the single station (e.g., starting with a first starting SN) and a second portion of the single TID or the single station (e.g., starting with a second starting SN). The one or more BAs may, in aggregate, span a BA window (e.g., established at 815).

[0112] At 840, wireless device 805-a (e.g., at 840) may update one or more scoreboards based on the one or more BAs received at 835. For example, wireless device 805-a may update and maintain a single global scoreboard, and a controller of the upper MAC layer may update the single global scoreboard. In other examples, wireless device 805-a may update and maintain local scoreboards on a per-link basis, and a controller of each lower MAC layer may update their respective local scoreboard. In yet other examples, a controller of the upper MAC layer may update both a global scoreboard and respective local scoreboards. In another example, a controller of the upper MAC layer may update a global scoreboard while controllers of the lower MAC layers may up their respective local scoreboards. Such updating is also described in more detail with reference to FIGs. 3-5.

[0113] At 845, wireless device 805-a may retransmit any necessary packets (e.g., MPDUs) based on the scoreboard updated at 840. Retransmission of the packets may be over the same wireless links as the original transmission, or may be over different wireless links. In some examples, all retransmissions may occur over a particular wireless link, and the original transmission may or may not have occurred over the same link.

[0114] FIG. 9 shows a block diagram 900 of a wireless device 905 that supports multi- link BA management in accordance with aspects of the present disclosure. Wireless device 905 may be an example of aspects of a ST A 115 or an AP 105 as described herein. Wireless device 905 may include receiver 910, communications manager 915, and transmitter 920. Wireless device 905 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

[0115] Receiver 910 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to multi-link BA management, etc.). Information may be passed on to other components of the device. The receiver 910 may be an example of aspects of the transceiver 1235 described with reference to FIG. 12. The receiver 910 may utilize a single antenna or a set of antennas.

[0116] Communications manager 915 may be an example of aspects of the

communications manager 1215 described with reference to FIG. 12. Communications manager 915 and/or at least some of its various sub-components may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions of the communications manager 915 and/or at least some of its various sub-components may be executed by a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure. The

communications manager 915 and/or at least some of its various sub-components may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical devices. In some examples, communications manager 915 and/or at least some of its various subcomponents may be a separate and distinct component in accordance with various aspects of the present disclosure. In other examples, communications manager 915 and/or at least some of its various sub-components may be combined with one or more other hardware

components, including but not limited to an I/O component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

[0117] In cases where communications manager 915 is within a device transmitting multi-link communications (e.g., a first wireless device), communications manager 915 may establish a block acknowledgement agreement for a set of wireless links used for

communications in parallel between the first wireless device (e.g., the device transmitting multi-link communications) and a second wireless device (e.g., a device receiving multi-link communications and transmitting corresponding block acknowledgements). Communications manager 915 may format data to be transmitted to the second wireless device into a set of data units and assign, to each of the set of data units, a respective one of a set of sequence numbers common to the set of wireless links. Communications manager 915 may then transmit the set of data units to the second wireless device over one or more of the set of wireless links, and receive a set of block acknowledgements, each of the set of block acknowledgements indicating one or more of the set of common sequence numbers.

[0118] In cases where communications manager 915 is within a device receiving multi- link communications (e.g., a first wireless device), communications manager 915 may establish a block acknowledgement agreement for a set of wireless links used for

communications in parallel between the first wireless device (e.g., the device receiving multi- link communications and transmitting corresponding block acknowledgements) and a second wireless device (e.g., a device transmitting multi-link communications). Communications manager 915 may receive a set of data units from the second wireless device over one or more of the set of wireless links, each data unit of the set of data units associated with one of a set of sequence numbers common to the set of wireless links. Communications manager 915 may then transmit a set of block acknowledgements in response to the set of data units, each of the set of block acknowledgements indicating one or more of the set of common sequence numbers.

[0119] Transmitter 920 may transmit signals generated by other components of the device. In some examples, the transmitter 920 may be collocated with a receiver 910 in a transceiver module. For example, the transmitter 920 may be an example of aspects of the transceiver 1235 described with reference to FIG. 12. The transmitter 920 may utilize a single antenna or a set of antennas.

[0120] FIG. 10 shows a block diagram 1000 of a wireless device 1005 that supports multi-link BA management in accordance with aspects of the present disclosure. Wireless device 1005 may be an example of aspects of a wireless device 905 or a ST A 115 or an AP 105 as described with reference to FIG. 9. Wireless device 1005 may include receiver 1010, communications manager 1015, and transmitter 1020. Wireless device 1005 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

[0121] Receiver 1010 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to multi-link BA management, etc.). Information may be passed on to other components of the device. The receiver 1010 may be an example of aspects of the transceiver 1235 described with reference to FIG. 12. The receiver 1010 may utilize a single antenna or a set of antennas.

[0122] Communications manager 1015 may be an example of aspects of the

communications manager 1215 described with reference to FIG. 12. Communications manager 1015 may also include BA agreement manager 1025, data unit manager 1030, SN manager 1035, multi-link manager 1040, and BA manager 1045.

[0123] BA agreement manager 1025 may establish a block acknowledgement agreement for a set of wireless links used for communications in parallel between a transmitting wireless device and a receiving wireless device.

[0124] Data unit manager 1030 may format data, at a transmitting device, to be transmitted to the receiving wireless device into a set of data units.

[0125] SN manager 1035 may assign, to each of the set of data units, a respective one of a set of sequence numbers common to the set of wireless links. In some cases, SN manager 1035 may assign a respective sequence number of a second set of sequence numbers to each of a first set of data units of the set of data units to be transmitted over a first wireless link of the set of wireless links, and assign a respective sequence number of a third set of sequence numbers to each of a second set of data units of the set of data units to be transmitted over a second wireless link of the set of wireless links. In some cases, a received set of block acknowledgements may further indicate one or more sequence numbers of the second set of sequence numbers for the first set of data units, or one or more sequence numbers of the third set of sequence numbers for the second set of data units, or a combination thereof.

[0126] Multi-link manager 1040 may transmit the set of data units to the second wireless device over one or more of the set of wireless links, transmit a second set of data units of the set of data units to the second wireless device over a second wireless link of the set of wireless links, and receive a set of data units from the second wireless device over one or more of the set of wireless links, each data unit of the set of data units associated with one of a set of sequence numbers common to the set of wireless links. In some cases, transmitting the set of data units to the second wireless device over one or more of the set of wireless data links further includes: transmitting a first set of data units of the set of data units to the second wireless device over a first wireless link of the set of wireless links.

[0127] BA manager 1045 may receive a set of block acknowledgements, each of the set of block acknowledgements indicating one or more of the set of common sequence numbers, receive a second set of the set of block acknowledgement over the second wireless link, where the second set of the set of block acknowledgements is for the second set of the set of data units, receive the set block acknowledgements over the first wireless link, the set of block acknowledgements for both the first set of the set of data units and the second set of the set of data units, transmit a set of block acknowledgements in response to the set of data units, each of the set of block acknowledgements indicating one or more of the set of common sequence numbers, exchange block acknowledgement capability information with the second wireless device, where the block acknowledgement agreement is established based on the exchanged block acknowledgement capability information, decompress a block acknowledgement bitmap of the received set of block acknowledgements to identify the one or more of the set of common sequence numbers, receive a second set of the set of data units from the wireless device over a second wireless link of the set of wireless links, each data unit of the second set associated with one of the set of common sequence numbers, and received set of block acknowledgements in aggregate span a block acknowledgement window. In some cases, receiving the set of block acknowledgements further includes:

receiving a first set of the set of block acknowledgement over the first wireless link, where the first set of the set of block acknowledgements is for the first set of the set of data units. In some cases, a block acknowledgement of the set of block acknowledgements includes a multi-traffic identifier (TID) block acknowledgement to acknowledge or not acknowledge a single TID or a single station. In some cases, receiving the set of block acknowledgements includes: receiving, in the multi-TID block acknowledgement, a first portion associated with a first starting sequence number and a second portion associated with a second starting sequence number, where the first portion and the second portion are for the single TID or the single station. In some cases, transmitting the set of block acknowledgements further includes: transmitting a multi -traffic identifier (TID) block acknowledgement to acknowledge or not acknowledge a single TID or a single station, the multi-TID block acknowledgement including a first portion associated with a first starting sequence number and a second portion associated with a second starting sequence number, where the first portion and the second portion are for the single TID or the single station. In some cases, receiving the set of data units from the second wireless device over the one or more of the set of wireless links further includes: receiving a first set of a set of data units from the wireless device over a first wireless link of the set of wireless links, each data unit of the first set associated with one of the set of common sequence numbers. In some cases, each of the set of block

acknowledgements further indicate: one or more of a first set of sequence numbers for the received first set of data units; or one or more of a second set of sequence numbers for the received second set of data units.

[0128] Transmitter 1020 may transmit signals generated by other components of the device. In some examples, the transmitter 1020 may be collocated with a receiver 1010 in a transceiver module. For example, the transmitter 1020 may be an example of aspects of the transceiver 1235 described with reference to FIG. 12. The transmitter 1020 may utilize a single antenna or a set of antennas.

[0129] FIG. 11 shows a block diagram 1100 of a communications manager 1115 that supports multi-link BA management in accordance with aspects of the present disclosure. The communications manager 1115 may be an example of aspects of a communications manager 915, a communications manager 1015, or a communications manager 1215 described with reference to FIGs. 9, 10, and 12. The communications manager 1115 may include BA agreement manager 1120, data unit manager 1125, SN manager 1130, multi-link manager 1135, BA manager 1140, BA scoreboard manager 1145, and BA capabilities manager 1150. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses).

[0130] BA agreement manager 1120 may establish a block acknowledgement agreement for a set of wireless links used for communications in parallel between the first wireless device and a second wireless device.

[0131] Data unit manager 1125 may format data to be transmitted to the second wireless device into a set of data units.

[0132] SN manager 1130 may assign, to each of the set of data units, a respective one of a set of sequence numbers common to the set of wireless links, assign a respective sequence number of a second set of sequence numbers to each of a first set of data units of the set of data units to be transmitted over a first wireless link of the set of wireless links, and assign a respective sequence number of a third set of sequence numbers to each of a second set of data units of the set of data units to be transmitted over a second wireless link of the set of wireless links. In some cases, the received set of block acknowledgements further indicate one or more sequence numbers of the second set of sequence numbers for the first set of data units, or one or more sequence numbers of the third set of sequence numbers for the second set of data units, or a combination thereof.

[0133] In a transmitting device (e.g., in a first device), multi-link manager 1135 may transmit the set of data units to a second wireless device (e.g., a receiving device) over one or more of the set of wireless links, and transmit a second set of data units of the set of data units to the second wireless device over a second wireless link of the set of wireless links. In some cases, transmitting the set of data units to the second wireless device over one or more of the set of wireless data links further includes transmitting a first set of data units of the set of data units to the second wireless device over a first wireless link of the set of wireless links.

[0134] In a receiving device (e.g., a first device) multi-link manager 1135 may receive a set of data units from a second wireless device (e.g., a transmitting device) over one or more of the set of wireless links, each data unit of the set of data units associated with one of a set of sequence numbers common to the set of wireless links. [0135] In a transmitting device (e.g., a first device), BA manager 1140 may receive a set of block acknowledgements, each of the set of block acknowledgements indicating one or more of the set of common sequence numbers. BA manager 1140 may receive a second set of the set of block acknowledgement over the second wireless link, where the second set of the set of block acknowledgements is for the second set of the set of data units. BA manager 1140 may receive the set block acknowledgements over the first wireless link, the set of block acknowledgements for both the first set of the set of data units and the second set of the set of data units. In some cases, BA manager 1140 may decompress a block

acknowledgement bitmap of the received set of block acknowledgements to identify the one or more of the set of common sequence numbers. In some cases, BA manager 1140 may receive a second set of the set of data units from the second wireless device over a second wireless link of the set of wireless links, each data unit of the second set associated with one of the set of common sequence numbers. BA manager 1140 may receive a set of block acknowledgements in aggregate span a block acknowledgement window. In some cases, receiving the set of block acknowledgements further includes receiving a first set of the set of block acknowledgement over the first wireless link, where the first set of the set of block acknowledgements is for the first set of the set of data units. In some cases, a block acknowledgement of the set of block acknowledgements includes a multi-TID block acknowledgement to acknowledge or not acknowledge a single TID or a single station. In some cases, receiving the set of block acknowledgements includes receiving, in the multi- TID block acknowledgement, a first portion associated with a first starting sequence number and a second portion associated with a second starting sequence number, where the first portion and the second portion are for the single TID or the single station.

[0136] In some cases, BA manager 1140 may exchange block acknowledgement capability information with a second wireless device (e.g., a receiving device), where the block acknowledgement agreement is established based on the exchanged block

acknowledgement capability information. In some cases, the block acknowledgement capability information includes a block acknowledgement window size, or a wireless link identifier, or a combination thereof.

[0137] In a receiving device (e.g., a first device), BA manager 1140 may transmit a set of block acknowledgements in response to the set of data units, each of the set of block acknowledgements may indicate one or more of the set of common sequence numbers. In some cases, BA manager 1140 may exchange block acknowledgement capability information with a second wireless device (e.g., a transmitting device), where the block acknowledgement agreement is established based on the exchanged block acknowledgement capability information. In some cases, transmitting the set of block acknowledgements further includes transmitting a multi-TID block acknowledgement to acknowledge or not acknowledge a single TID or a single station, the multi-TID block acknowledgement including a first portion associated with a first starting sequence number and a second portion associated with a second starting sequence number, where the first portion and the second portion are for the single TID or the single station. In some cases, receiving the set of data units from the second wireless device over the one or more of the set of wireless links further includes receiving a first set of a set of data units from the second wireless device over a first wireless link of the set of wireless links, each data unit of the first set associated with one of the set of common sequence numbers. In some cases, each of the set of block acknowledgements further indicate one or more of a first set of sequence numbers for the received first set of data units or one or more of a second set of sequence numbers for the received second set of data units.

[0138] In some cases, BA manager 1140 may exchange block acknowledgement capability information with a second wireless device (e.g., a transmitting device), where the block acknowledgement agreement is established based on the exchanged block

acknowledgement capability information. In some cases, the block acknowledgement capability information includes a block acknowledgement window size, or a wireless link identifier, or a combination thereof.

[0139] In some cases, BA manager 1140 may receive a plurality of block

acknowledgements (in response to multiple data units) over at least one wireless link of one or more of multiple wireless links used for communications in parallel between two wireless devices, and the multi-link manager 1135 may transmit at least a portion of the multiple data units to the wireless device over a second wireless link of the multiple wireless links, the second wireless link a unidirectional wireless link that is exclusive of the at least one wireless link used to receive the block acknowledgements.

[0140] BA scoreboard manager 1145 may update, based on one or more of the set of received block acknowledgments, a scoreboard to track data units acknowledged or not acknowledged by the second wireless device for the set of wireless links and update, based on the received set of block acknowledgments, a first scoreboard to track data units

acknowledged or not acknowledged by the second wireless device for a first wireless link of the set of wireless links, and a second scoreboard to track data units acknowledged or not acknowledged by the second wireless device for a second wireless link of the set of wireless links.

[0141] BA capabilities manager 1150 may determine a first block acknowledgement window size for the set of wireless links based on the exchanged block acknowledgement capability information and establish a second block acknowledgement window size for a first wireless link of the set of wireless links, the second block acknowledgement window size less than the first block acknowledgement window size.

[0142] FIG. 12 shows a diagram of a system 1200 including a device 1205 that supports multi-link BA management in accordance with aspects of the present disclosure. Device 1205 may be an example of or include the components of wireless device 905, wireless device 1005, or a STA 115 or an AP 105 as described above, e.g., with reference to FIGs. 9 and 10. Device 1205 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including

communications manager 1215, processor 1220, memory 1225, software 1230, transceiver 1235, antenna 1240, and I/O controller 1245. These components may be in electronic communication via one or more buses (e.g., bus 1210).

[0143] Processor 1220 may include an intelligent hardware device, (e.g., a general- purpose processor, a DSP, a central processing unit (CPU), a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, processor 1220 may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into processor 1220. Processor 1220 may be configured to execute computer-readable instructions stored in a memory to perform various functions (e.g., functions or tasks supporting multi-link BA management).

[0144] Memory 1225 may include random access memory (RAM) and read only memory (ROM). The memory 1225 may store computer-readable, computer-executable software 1230 including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 1225 may contain, among other things, a basic input/output system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices. [0145] Software 1230 may include code to implement aspects of the present disclosure, including code to support multi-link BA management. Software 1230 may be stored in a non- transitory computer-readable medium such as system memory or other memory. In some cases, the software 1230 may not be directly executable by the processor but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

[0146] Transceiver 1235 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 1235 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 1235 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

[0147] In some cases, the wireless device may include a single antenna 1240. However, in some cases the device may have more than one antenna 1240, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

[0148] I/O controller 1245 may manage input and output signals for device 1205. I/O controller 1245 may also manage peripherals not integrated into device 1205. In some cases, I/O controller 1245 may represent a physical connection or port to an external peripheral. In some cases, I/O controller 1245 may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operating system. In other cases, I/O controller 1245 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, I/O controller 1245 may be implemented as part of a processor. In some cases, a user may interact with device 1205 via I/O controller 1245 or via hardware components controlled by I/O controller 1245.

[0149] FIG. 13 shows a flowchart illustrating a method 1300 for multi-link BA management in accordance with aspects of the present disclosure. The operations of method 1300 may be implemented by a STA 115 or an AP 105 or its components as described herein. For example, the operations of method 1300 may be performed by a communications manager as described with reference to FIGs. 9 through 12. In some examples, a STA 115 or an AP 105 may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the STA 115 or an AP 105 may perform aspects of the functions described below using special-purpose hardware. [0150] At 1305 the STA 115 (or an AP 105) may establish a block acknowledgement agreement for a plurality of wireless links used for communications in parallel between the STA 115 or the AP 105 (e.g., the first wireless device) and a second wireless device (e.g., some other receiving STA 115 or AP 105). The operations of 1305 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1305 may be performed by a BA agreement manager as described with reference to FIGs. 9 through 12.

[0151] At 1310 the STA 115 (or the AP 105) may format data to be transmitted to the second wireless device (e.g., a receiving device) into a plurality of data units. The operations of 1310 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1310 may be performed by a data unit manager as described with reference to FIGs. 9 through 12.

[0152] At 1315 the STA 1 15 (or the AP 105) may assign, to each of the plurality of data units, a respective one of a set of sequence numbers common to the plurality of wireless links. The operations of 1315 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1315 may be performed by a SN manager as described with reference to FIGs. 9 through 12.

[0153] At 1320 the STA 115 (or the AP 105) may transmit the plurality of data units to the second wireless device (e.g., the receiving device) over one or more of the plurality of wireless links. The operations of 1320 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1320 may be performed by a multi- link manager as described with reference to FIGs. 9 through 12.

[0154] At 1325 the STA 115 (or the AP 105) may receive a plurality of block

acknowledgements, each of the plurality of block acknowledgements indicating one or more of the set of common sequence numbers. The operations of 1325 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1325 may be performed by a BA manager as described with reference to FIGs. 9 through 12.

[0155] FIG. 14 shows a flowchart illustrating a method 1400 for multi-link BA management in accordance with aspects of the present disclosure. The operations of method 1400 may be implemented by a STA 115 or an AP 105 or its components as described herein. For example, the operations of method 1400 may be performed by a communications manager as described with reference to FIGs. 9 through 12. In some examples, a STA 115 or an AP 105 may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the STA 115 or an AP 105 may perform aspects of the functions described below using special-purpose hardware.

[0156] At 1405 the STA 115 (or an AP 105) may establish a block acknowledgement agreement for a plurality of wireless links used for communications in parallel between the STA 115 or the AP 105 (e.g., the first wireless device) and a second wireless device (e.g., a receiving device). The operations of 1405 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1405 may be performed by a BA agreement manager as described with reference to FIGs. 9 through 12.

[0157] At 1410 the STA 115 (or the AP 105) may format data to be transmitted to the second wireless device (e.g., the receiving device) into a plurality of data units. The operations of 1410 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1410 may be performed by a data unit manager as described with reference to FIGs. 9 through 12.

[0158] At 1415 the STA 1 15 (or the AP 105) may assign, to each of the plurality of data units, a respective one of a set of sequence numbers common to the plurality of wireless links. The operations of 1415 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1415 may be performed by a SN manager as described with reference to FIGs. 9 through 12.

[0159] At 1420 the STA 115 (or the AP 105) may transmit the plurality of data units to the second wireless device (e.g., the receiving device) over one or more of the plurality of wireless links. The operations of 1420 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1420 may be performed by a multi- link manager as described with reference to FIGs. 9 through 12.

[0160] At 1425 the STA 115 (or the AP 105) may receive a plurality of block

acknowledgements, each of the plurality of block acknowledgements indicating one or more of the set of common sequence numbers. The operations of 1425 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1425 may be performed by a BA manager as described with reference to FIGs. 9 through 12.

[0161] At 1430 the STA 115 (or the AP 105) may update, based at least in part on one or more of the plurality of received block acknowledgments, a scoreboard to track data units acknowledged or not acknowledged by the second wireless device (e.g., the receiving device) for the plurality of wireless links. The operations of 1430 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1430 may be performed by a BA scoreboard manager as described with reference to FIGs. 9 through 12.

[0162] FIG. 15 shows a flowchart illustrating a method 1500 for multi-link BA management in accordance with aspects of the present disclosure. The operations of method 1500 may be implemented by a STA 115 or an AP 105 or its components as described herein. For example, the operations of method 1500 may be performed by a communications manager as described with reference to FIGs. 9 through 12. In some examples, a STA 115 or an AP 105 may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the STA 115 or an AP 105 may perform aspects of the functions described below using special-purpose hardware.

[0163] At 1505 the STA 115 (or an AP 105) may establish a block acknowledgement agreement for a plurality of wireless links used for communications in parallel between the STA 115 or the AP 105 (e.g., the first wireless device) and a second wireless device (e.g., a receiving device). The operations of 1505 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1505 may be performed by a BA agreement manager as described with reference to FIGs. 9 through 12.

[0164] At 1510 the STA 115 (or the AP 105) may format data to be transmitted to the second wireless device (e.g., the receiving device) into a plurality of data units. The operations of 1510 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1510 may be performed by a data unit manager as described with reference to FIGs. 9 through 12.

[0165] At 1515 the STA 1 15 (or the AP 105) may assign, to each of the plurality of data units, a respective one of a set of sequence numbers common to the plurality of wireless links. The operations of 1515 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1515 may be performed by a SN manager as described with reference to FIGs. 9 through 12.

[0166] At 1520 the STA 115 (or the AP 105) may transmit the plurality of data units to the second wireless device (e.g., the receiving device) over one or more of the plurality of wireless links. The operations of 1520 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1520 may be performed by a multi- link manager as described with reference to FIGs. 9 through 12.

[0167] At 1525 the STA 115 (or the AP 105) may receive a plurality of block

acknowledgements, each of the plurality of block acknowledgements indicating one or more of the set of common sequence numbers. The operations of 1525 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1525 may be performed by a BA manager as described with reference to FIGs. 9 through 12.

[0168] At 1530 the STA 115 (or the AP 105) may update, based at least in part on the received plurality of block acknowledgments, a first scoreboard to track data units

acknowledged or not acknowledged by the second wireless device (e.g., the receiving device) for a first wireless link of the plurality of wireless links, and a second scoreboard to track data units acknowledged or not acknowledged by the second wireless device (e.g., the receiving device) for a second wireless link of the plurality of wireless links. The operations of 1530 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1530 may be performed by a BA scoreboard manager as described with reference to FIGs. 9 through 12.

[0169] FIG. 16 shows a flowchart illustrating a method 1600 for multi-link BA management in accordance with aspects of the present disclosure. The operations of method 1600 may be implemented by a STA 115 or an AP 105 or its components as described herein. For example, the operations of method 1600 may be performed by a communications manager as described with reference to FIGs. 9 through 12. In some examples, a STA 115 or an AP 105 may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the STA 115 or an AP 105 may perform aspects of the functions described below using special-purpose hardware.

[0170] At 1605 the STA 115 (or an AP 105) may establish a block acknowledgement agreement for a plurality of wireless links used for communications in parallel between the STA 115 or the AP 105 (e.g., the first wireless device) and a second wireless device (e.g., a multi-link receiving device). The operations of 1605 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1605 may be performed by a BA agreement manager as described with reference to FIGs. 9 through 12.

[0171] At 1610 the STA 115 (or the AP 105) may format data to be transmitted to the second wireless device (e.g., the receiving device) into a plurality of data units. The operations of 1610 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1610 may be performed by a data unit manager as described with reference to FIGs. 9 through 12.

[0172] At 1615 the STA 1 15 (or the AP 105) may assign, to each of the plurality of data units, a respective one of a set of sequence numbers common to the plurality of wireless links. The operations of 1615 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1615 may be performed by a SN manager as described with reference to FIGs. 9 through 12.

[0173] At 1620 the STA 115 (or the AP 105) may assign a respective sequence number of a second set of sequence numbers to each of a first set of data units of the plurality of data units to be transmitted over a first wireless link of the plurality of wireless links. The operations of 1620 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1620 may be performed by a SN manager as described with reference to FIGs. 9 through 12.

[0174] At 1625 the STA 115 (or the AP 105) may assign a respective sequence number of a third set of sequence numbers to each of a second set of data units of the plurality of data units to be transmitted over a second wireless link of the plurality of wireless links. The operations of 1625 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1625 may be performed by a SN manager as described with reference to FIGs. 9 through 12.

[0175] At 1630 the STA 115 (or the AP 105) may transmit the plurality of data units to the second wireless device over one or more of the plurality of wireless links. The operations of 1630 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1630 may be performed by a multi-link manager as described with reference to FIGs. 9 through 12.

[0176] At 1635 the STA 115 (or the AP 105) may receive a plurality of block

acknowledgements, each of the plurality of block acknowledgements indicating one or more of the set of common sequence numbers. The operations of 1635 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1635 may be performed by a BA manager as described with reference to FIGs. 9 through 12. [0177] FIG. 17 shows a flowchart illustrating a method 1700 for multi-link BA management in accordance with aspects of the present disclosure. The operations of method 1700 may be implemented by a STA 115 or an AP 105 or its components as described herein. For example, the operations of method 1700 may be performed by a communications manager as described with reference to FIGs. 9 through 12. In some examples, a STA 115 or an AP 105 may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the STA 115 or an AP 105 may perform aspects of the functions described below using special-purpose hardware.

[0178] At 1705 the STA 115 (or an AP 105) may establish a block acknowledgement agreement for a plurality of wireless links used for communications in parallel between the STA 115 or the AP 105 (e.g., the first wireless device) and a second wireless device (e.g., a device transmitting multi-link communications). The operations of 1705 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1705 may be performed by a BA agreement manager as described with reference to FIGs. 9 through 12.

[0179] At 1710 the STA 115 (or the AP 105) may receive a plurality of data units from the second wireless device (e.g., the transmitting device) over one or more of the plurality of wireless links, each data unit of the plurality of data units associated with one of a set of sequence numbers common to the plurality of wireless links. The operations of 1710 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1710 may be performed by a multi-link manager as described with reference to FIGs. 9 through 12.

[0180] At 1715 the STA 115 (or the AP 105) may transmit a plurality of block

acknowledgements in response to the plurality of data units, each of the plurality of block acknowledgements indicating one or more of the set of common sequence numbers. The operations of 1715 may be performed according to the methods described herein. In certain examples, aspects of the operations of 1715 may be performed by a BA manager as described with reference to FIGs. 9 through 12.

[0181] It should be noted that the methods described above describe possible

implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Furthermore, aspects from two or more of the methods may be combined. [0182] Techniques described herein may be used for various wireless communications systems such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and other systems. The terms "system" and "network" are often used interchangeably. A code division multiple access (CDMA) system may implement a radio technology such as

CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases may be commonly referred to as CDMA2000 IX, IX, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 lxEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A time division multiple access (TDMA) system may implement a radio technology such as Global System for Mobile Communications (GSM). An orthogonal frequency division multiple access (OFDMA) system may implement a radio technology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc.

[0183] The wireless communications system or systems described herein may support synchronous or asynchronous operation. For synchronous operation, the stations may have similar frame timing, and transmissions from different stations may be approximately aligned in time. For asynchronous operation, the stations may have different frame timing, and transmissions from different stations may not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operations.

[0184] The downlink transmissions described herein may also be called forward link transmissions while the uplink transmissions may also be called reverse link transmissions. Each communication link described herein— including, for example, wireless

communications system 100 and 200 of FIGs. 1 and 2— may include one or more carriers, where each carrier may be a signal made up of multiple sub-carriers (e.g., waveform signals of different frequencies).

[0185] The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term "exemplary" used herein means "serving as an example, instance, or illustration," and not "preferred" or

"advantageous over other examples." The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

[0186] In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.

[0187] Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0188] The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0189] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described above may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Also, as used herein, including in the claims, "or" as used in a list of items (for example, a list of items prefaced by a phrase such as "at least one of or "one or more of) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase "based on" shall not be construed as a reference to a closed set of conditions. For example, an exemplary step that is described as "based on condition A" may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" shall be construed in the same manner as the phrase "based at least in part on."

[0190] Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media can comprise RAM, ROM, electrically erasable programmable read only memory (EEPROM), compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general- purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

[0191] The description herein is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.