Patent Description:
The invention generally relates to the field of wireless communications. More specifically, the present invention relates to a method and an apparatus for simultaneously transmitting frames over multiple links in a wireless network.

Modern electronic devices typically send and receive data with other electronic devices wirelessly using Wi-Fi, and many of these devices are "dual band" devices that include at least two wireless transceivers capable of operating in different frequency bands, e.g., <NUM>, <NUM>, and <NUM>. In most cases, a wireless device will communicate over only a single band at a time. For example, older and low-power devices, e.g., battery powered devices, often operate on the <NUM> band. Newer devices and devices that require greater bandwidth often operate on the <NUM> band. The availability of the <NUM> band is a recent advancement and can provide higher performance, lower latency, and faster data rates.

In some cases, the use of a single band may not satisfy the bandwidth needs of certain devices. Therefore, some developing approaches to wireless communication increase communication bandwidth by operating on multiple bands concurrently (technically called link aggregation or multi-link operation). Multi-link operations can provide higher network throughput and improved network flexibility compared to traditional techniques for wireless communication.

Under existing standards, frame aggregation can be used to collect frames to be transmitted to one or multiple destinations and enclose them in a single <NUM>. 11n frame for increased efficiency. An Aggregate MAC Service Data Unit (A-MSDU) includes sub-frame headers having destination address (DA) and sender address (SA) parameter values that map to the same receiver address (RA) and transmitter address (TA) values. However, it is currently difficult to define the destination address (DA) and source address (SA) in an A-MSDU sub-frame header using multi-link operations for fragmented frames because MAC service data unit (MSDU) aggregation is performed before MAC protocol data unit (MPDU) generation.

Moreover, the wireless AP requires a means to determine the capabilities of the associated devices, for example, to determine if the recipient wireless station (STA) supports multi-link fragmentation and to determine A-MSDU capability requirements of the recipient STA. Each MAC entity of the recipient STA can have different A-MSDU capabilities and configurations, such as different numbers of MSDUs that can be carried in an A-MSDU, different maximum MPDU lengths that the STA is capable of receiving, and different maximum A-MSDU lengths that the STA is capable of receiving. Transmitting data to different MAC entities having different A-MSDU capabilities can lead to performance inefficiencies when the different A-MSDU capabilities are not accounted for by the transmitting device. <CIT> discloses a station in a basic service set of a wireless network that includes layer <NUM> bridging functionality to one or more nodes in external networks. An access point in the basic service set acts as a control plane for the bridging functionality. The access point includes bridge address learning and a bridging table to map destination addresses and associated bridging stations. <CIT> discloses a method for wireless communication, wherein parallel communications over multiple wireless links are supported.

Accordingly, embodiments of the present invention provide techniques for simultaneously transmitting frames of an A-MSDU over multiple links in a multi-link operation between wireless devices (e.g., a wireless STA and a wireless access point (AP)). The A-MSDU can be aggregated to satisfy capability requirements of the transmitting device and/or the receiving device. Moreover, the A-MSDU can be fragmented, for example, to satisfy an MPDU length requirement of the transmitting device and/or the receiving device. Some embodiments disclosed herein use a virtual mac address of an logical link control (LLC) sublayer interface to define parameters values of an A-MSDU sub-frame header (e.g., SA and DA) for routing the respective frame to the LLC sublayer interface of the receiving device. Methods and apparatus according to the invention are defined in the independent claims. The dependent claims define preferred embodiments thereof.

According to one embodiment, which is not an embodiment according to the invention, a method of transmitting data by a transmitting device in a multi-link operation over a wireless network is disclosed. The method includes determining that a receiving device is capable of multi-link fragmentation, the receiving device and the transmitting device are operable to communicate over a first wireless link and a second wireless link, determining a first media access control (MAC) protocol data unit (MPDU) length capability of the receiving device for the first wireless link and a second MPDU length capability of the receiving device for the second wireless link, and transmitting a first frame over the first wireless link and transmitting a second frame over the second wireless link to the receiving device in the multi-link operation.

Preferably, the method includes determining that a length of the A-MSDU is larger than the first MPDU length capability, and fragmenting an aggregate MAC protocol service unit (A-MSDU) into a first fragmented frame and a second fragmented frame according to the MPDU length capabilities, the A-MSDU is fragmented using fragments that are smaller than the MPDU length capability of the first wireless link, and the first frame includes the first fragmented frame and the second frame comrpsies the second fragmented frame.

Preferably, a length of the A-MSDU is greater than at least one of the first MPDU length capability and the second MPDU length capability, a length of the first fragmented frame is not greater than the first MPDU length capability, and a length of the second fragmented frame is not greater than the second MPDU length capability.

Preferably the transmitting the first frame over the first wireless link is performed simultaneously with transmitting the second frame over the second wireless link.

Preferably the first frame and the second frame are associated with the same traffic identifier (TID) allocated to the first wireless link and the second wirelessl link.

Preferably, the method includes receiving an extended capabilities element from the receiving device including an A-MSDU capability requirement, and aggregating the A-MSDU to satisfy the A-MSDU capability requirement of the extended capabilities element.

Preferably the receiving device is further operable to communicate over a third wireless link, and the aggregating the A-MSDU to satisfy the A-MSDU capability of the extended capabilities element includes identifying an eligible link set that satisfies the A-MSDU capability of the extended capabilities element, wherein the eligible link set includes at least one of: the first wireless link; the second wireless link; and the third wireless link.

Preferably, the first wireless link includes a <NUM> wireless link, the second wireless link includes a <NUM> wireless link, and the third wireless link includes a <NUM> wireless link.

According to a different embodiment, which is an embodiment according to the invention, a method of transmitting data to a receiving device by a transmitting device in a multi-link operation over a wireless network is disclosed. The method includes receiving a transmission opportunity (TXOP) on a first wireless link at a first wireless station (STA) instance of a plurality of wireless STA instances of the transmitting device, setting a SA field of an aggregate media access control (MAC) protocol service unit (A-MSDU) sub-frame header of the A-MSDU according to a virtual MAC address of an logical link control (LLC) sublayer interface of the transmitting device, setting a DA field of the A-MSDU sub-frame header of the A-MSDU according to a virtual MAC address of an LLC sublayer interface of the receiving device for delivering the A-MSDU to an LLC sublayer of the receiving device, and transmitting the A-MSDU to the receiving device over the first wireless link.

The method includes setting a TA field of a MAC header of the A-MSDU according to a MAC address of the first wireless STA instance, and setting an RA field of the MAC header of the A-MSDU according to a MAC address of a wireless AP instance of the receiving device.

The method includes receiving a transmission opportunity (TXOP) on a second wireless link at a second wireless STA instance of the plurality of wireless STA instances of the transmitting device, setting a SA field of an A-MSDU sub-frame header of a second A-MSDU according to the virtual MAC address of the LLC sublayer interface of the transmitting device, setting a DA field of the A-MSDU sub-frame header of the second A-MSDU according to the virtual MAC address of the LLC sublayer interface of the receiving device for delivering the second A-MSDU to the LLC sublayer of the receiving device, and transmitting the second A-MSDU to the receiving device over the second wireless link.

The A-MSDU is transmitted simultaneously with the second A-MSDU. The A-MSDU and the second A-MSDU include fragmented frames of the same original A-MSDU.

The virtual MAC address of the LLC sublayer interface of the transmitting device corresponds to a MAC address of a wireless STA instance of the plurality of wireless STA instances.

The virtual MAC address of the LLC sublayer of the receiving device corresponds to a MAC address of a wireless AP instance of the receiving device.

According to another embodiment, which is an embodiment according to the invention, an apparatus for transmitting data to a receiving device in a multi-link operation over a wireless network. The apparatus includes a multi-band wireless station (STA) including a plurality of wireless STA instances, each wireless STA instance of the plurality of wireless STA instances is associated with a respective media access control (MAC) address, and an logical link control (LLC) sublayer interface associated with a first MAC address of a first wireless STA instance of the plurality of wireless STA instances. The multi-band wireless STA is operable to receive a transmission opportunity (TXOP) for transmitting an aggregate MAC protocol service unit (A-MSDU) at a second wireless STA instance of a plurality of wireless STA instances of the transmitting device, set an SA field of an A-MSDU sub-frame header of the A-MSDU according to a virtual MAC address of the LLC sublayer interface of the transmitting device, set a DA field of the A-MSDU sub-frame header of the A-MSDU according to a virtual MAC address of an LLC sublayer interface of the receiving device for delivering the A-MSDU to an LLC sublayer of the receiving device, and transmit the A-MSDU to the receiving device using the virtual MAC addresses in the A-MSDU sub-frame header.

The multi-band wireless STA is further operable to aggregate the A-MSDU for transmission using the A-MSDU sub-frame header.

The multi-band wireless STA is further operable to aggregate the A-MSDU according to an A-MSDU capability requirement of the receiving device.

The A-MSDU capability requirement of the receiving device includes a maximum mac protocol data unit (MPDU) length, and the STA is further operable to aggregate the A-MSDU using a length that satisfies the A-MSDU capability requirement.

The plurality of wireless STA instances communicate with the receiving device over a plurality of wireless links, and the multi-band wireless STA is further operable to aggregate the A-MSDU according to an A-MSDU capability requirement of the receiving device by determining an eligible link set of the plurality of wireless links that satisfy the A-MSDU capability requirement of the receiving device.

The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention:.

Portions of the detailed description that follow are presented and discussed in terms of a method. Although steps and sequencing thereof are disclosed in a figure herein (e.g., <FIG>) describing the operations of this method, such steps and sequencing are exemplary. Embodiments are well suited to performing various other steps or variations of the steps recited in the flowchart of the figure herein, and in a sequence other than that depicted and described herein.

Some portions of the detailed description are presented in terms of procedures, steps, logic blocks, processing, and other symbolic representations of operations on data bits that can be performed on computer memory. These descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. A procedure, computer-executed step, logic block, process, etc., is here, and generally, conceived to be a self-consistent sequence of steps or instructions leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated in a computer system.

Unless specifically stated otherwise as apparent from the following discussions, it is appreciated that throughout, discussions utilizing terms such as "accessing," "configuring," "setting," "storing," "transmitting," "retransmitting," "authenticating," "identifying," "requesting," "reporting," "determining," or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.

As used herein, the term "EHT" refers generally to a recent generation of wireless communication (Wi-Fi) known as Extremely High Throughput (EHT) and is defined according to the IEEE <NUM>. 11be standards. The term station (STA) refers generally to an electronic device capable of sending and receiving data over Wi-Fi that is not operating as an access point (AP).

Multi-link operations can provide higher network throughput and improved network flexibility compared to traditional techniques for wireless communication. Embodiments of the present invention provide techniques for simultaneously transmitting frames of an A-MSDU over multiple links in a multi-link operation between wireless devices (e.g., a wireless STA and a wireless AP). The A-MSDU can be aggregated to satisfy capability requirements of the transmitting device and/or the receiving device. Moreover, the A-MSDU can be fragmented, for example, to satisfy an MPDU length requirement of the transmitting device and/or the receiving device. Some embodiments disclosed herein use a virtual mac address of an LLC sublayer interface to define parameters values of an A-MSDU sub-frame header (e.g., SA and DA) for routing the respective frame to the LLC sublayer.

With regard to <FIG>, an exemplary wireless communication system <NUM> including a multi-band cooperative AP <NUM> and a multi-band cooperative STA <NUM> are depicted according to embodiments of the present invention. The multi-band cooperative AP <NUM> includes a <NUM> transceiver <NUM> and a <NUM> transceiver <NUM>. Other types of transceivers that operate on different bands, such as <NUM> and above, can also be used by the multi-band cooperative AP <NUM> according to embodiments of the present invention. The transceivers <NUM> and <NUM> of AP <NUM> exchange data and information with cooperative management unit <NUM> that coordinates information sent and/or received by transceivers <NUM> and <NUM>.

The multi-band cooperative ST <NUM> includes a <NUM> transceiver <NUM> and a <NUM> transceiver <NUM>. Other types of transceivers that operate on different bands, such as <NUM> and above, can also be used by the multi-band cooperative STA <NUM> according to some embodiments of the present invention. The transceivers <NUM> and <NUM> of STA <NUM> exchange data and information with cooperative management unit <NUM> that coordinates information sent and received by transceivers <NUM> and <NUM> using <NUM> band wireless communication and <NUM> band wireless communication, respectively, although any well-known wireless communication band (e.g., <NUM>) can be used.

The multi-band cooperative AP <NUM> and the multi-band cooperative STA <NUM> have simultaneous transmission and reception capabilities for communicating using different wireless bands. The transmitters operating on the different bands can perform independent clear channel assessments (CCAs) using joint or intendent transmissions. Moreover, full duplex communication can be enabled by independent multi-band operation using FDD mode.

STA <NUM> transmitting frames using multiple bands simultaneously can mitigate delay and improve peak throughput of STA <NUM>. However, in some cases, transmitting frames using multiple bands simultaneously can degrade the performance of the basic service set (BSS) comprising STA <NUM>. For example, the performance of the BSS can be degraded when STA <NUM> operating on multiple bands simultaneously uses a substantial amount of the bandwidth available to the BSS due to the increased traffic. Therefore, the AP <NUM> can control which STAs are granted multi-band channel access, and the access can be terminated by the AP at any time, for example, based on changing network conditions or requirements.

Depending on certain conditions, such as traffic load, a non-AP STA may use fewer than all supported/available links in order to reduce energy consumption. Moreover, a non-AP STA may apply an independent power management for each link, and the AP can provide the TID-to-link mapping information for each link. Depending the Quality of Service (QoS) policy of the Basic Service Set (BSS), an AP may allocate the traffic to different links based on traffic type, such as voice, video, data, etc. For example, frames belonging to a first Traffic Identifier (TID <NUM>) can be allocated to a first link, and frames belonging to a second Traffic Identifier (TID <NUM>) can be allocated to a second link. In this case, the AP may provide the TID-to-link mapping information for both links to the wireless STA, where some data can only be sent on the first link, and other data can only be sent on the second link.

Data transmitted over a first wireless link, such as the <NUM> wireless link provided by <NUM> transceiver <NUM> or <NUM>, can be retransmitted over a different wireless link. For example, if a data transmission over the <NUM> wireless link is sent unsuccessfully (e.g., no acknowledgment received), the data can be retransmitted over the <NUM> wireless link provided by <NUM> transceiver <NUM>/<NUM>. The data transmission (e.g., a PPDU) can be originally encoded for transmission on a first wireless link (e.g., a <NUM> or <NUM> wireless link), and the retransmitted data can be prepared for transmission according to embodiments of the present invention described herein for encrypting data for retransmission in a multi-link environment.

<FIG> is a block diagram of an exemplary multi-link operation performed by a wireless STA according to embodiments of the present invention. The wireless STA obtains a transmission opportunity (TXOP) in multiple bands, including a <NUM> wireless band <NUM> and a <NUM> wireless band <NUM>. When the wireless STA obtains TXOPs in multiple bands, the STA can transmit frames in multiple bands simultaneously. As depicted in <FIG>, the wireless STA transmits PPDU1 (<NUM>) over <NUM> wireless band <NUM> and PPDU2 (<NUM>) over <NUM> wireless band <NUM> concurrently. As mentioned above, transmitting data over multiple links simultaneously according to embodiments of the present invention can mitigate delay and improve peak throughput of the wireless STA.

<FIG> is a block diagram of an exemplary multi-link operation using traffic identifiers (TIDs) performed by a wireless STA according to embodiments of the present invention. When the transmitted frames are under a block ack agreement, the add block acknowledgment(ADDBA) request frame can include more than one multi-band information element indicating the bands on which a wireless STA can send frames of the TID indicated in the ADDBA Request frame. When an STA is transmitting frames in one or more bands ("ongoing bands") and schedules a new frame transmission in a different band using frames under a block ack agreement, the STA chooses the scheduled frame from the same TID as the ongoing frame if the reordering buffer for the TID of the ongoing frame is available. Otherwise, the STA chooses the scheduled frame from a different TID than the ongoing frame.

As depicted in <FIG>, the STA simultaneously transmits data frame <NUM> on a <NUM> wireless band <NUM> and data frame <NUM> on a <NUM> wireless band <NUM>. Data frames corresponds to sequence Seq1 and data frame <NUM> corresponds to sequence Seq2 associated with TID1. The ongoing frame <NUM> is not under a block ack agreement (no block ack agreement on TID1). In this case, if data frame <NUM> of sequence Seq1 fails, the STA can retransmit data frame <NUM> in data frame <NUM>. It is possible that the recipient wireless device will deliver data frame <NUM> of sequence Seq2 to an upper layer before the recipient device delivers the retransmitted data frame <NUM> of Seq1 to the upper layer, which can be problematic. To avoid an out of order of delivery of frames to the upper layer (e.g., Seq2 before Seq1), when the frames are not transmitted under a block ACK agreement, the STA schedules a frame from a TID that is different than the TID of the ongoing frame. However, this approach may limit the gains achieved by the multi-link operation.

Alternatively, to maintain the performance capabilities of the multi-link operation, according to some embodiments, the STA schedules a frame from the same TID as the ongoing frame only if the ongoing frame has no retry attempts remaining, and the transmission end time of the scheduled frame is not earlier than the transmission end time of the ongoing frame. Otherwise, the STA schedules a frame having a TID that is different than the TID of the ongoing frame.

To schedule transmission of an aggregate MSDU (A-MSDU), the transmitting STA must define the destination address (DA) and source address (SA) in the A-MSDU sub-frame header for a MSDU transmitted in a multi-link operation. However, because MSDU aggregation is performed prior to the generation of the MPDUs, the DA and SA in the A-MSDU sub-frame header corresponding to the respective MPDU are determined independently on the link where the TXOP is obtained in a multi-link operation. In current MAC data plane architecture, A-MSDU aggregation is one of the first procedures performed at the TX side, and de-aggregation is one of the last procedures performed at the RX side. Accordingly, when an A-MSDU is carried in a QoS Data frame with a normal Ack policy, a wireless STA can support the reception of the A-MSDU sent by a high throughput (HT) STA when the A-MSDU is not aggregated within an A-MPDU (aggregated MPDU), or by a VHT STA when the A-MSDU is sent as a Single MPDU (S-MPDU).

For each block ack agreement, an STA can transmit an A-MSDU within a QoS Data frame under the block ack agreement unless the recipient indicates support for A-MSDU by setting the A-MSDU Supported field to '<NUM>' in the BlockAck Parameter Set field of the ADDBA Response frame. As mentioned above, the ADDBA Request frame can include more than one multi-band information element indicating the bands on which a wireless STA can send frames of the TID indicated in the ADDBA Request frame. Importantly, the wireless STA does not transmit an A-MSDU to a recipient wireless STA if the A-MSDU length exceeds the value indicated by the Maximum A-MSDU Length field of the HT Capabilities element received from the recipient STA.

The length of an A-MSDU transmitted in a VHT PPDU is limited by the maximum MPDU size supported by the recipient STA. Further, a VHT STA cannot transmit an A-MSDU that includes a number of MSDUs greater than the value indicated by the Max Number of MSDUs in an A-MSDU field of any Extended Capabilities element sent by the recipient STA, and an HT STA cannot transmit an A-MSDU that includes a number of MSDUs greater than the value indicated by the Max Number of MSDUs in an A-MSDU field of any Extended Capabilities element sent by the recipient STA.

<FIG> is a block diagram of an exemplary multi-link operation using multiple fragmented frames according to embodiments of the present invention. When a multi-band STA supports a dynamic fragmentation, it can perform fragmentation of an A-MSDU having a length that does not satisfy the Maximum MPDU Length capability of a link. Fragmentation is typically performed after A-MSDU aggregation. When a frame is fragmented, all segments carrying the fragmented frames are sent through one link unless the recipient STA supports the multi-link fragmentation. When the recipient STA indicates support for multi-link fragmentation, the transmitting multi-band STA can simultaneously send fragmented frames over multiple links when the Maximum MPDU Length capability of the link is greater than or equal to the size of the fragmented frames.

When an ongoing frame is a fragmented frame, the STA can choose one of the remaining fragmented frames to schedule for transmission. As depicted in <FIG>, the STA transmits ongoing data frame <NUM> including fragment Frag0 of sequence Seq1 (associated with TID1) over <NUM> wireless link <NUM>, and schedules data frame <NUM> including fragment Frag1 of sequence Seq1 (also associated with TID1) for transmission over <NUM> wireless link <NUM> when the Maximum MPDU Length capability of the <NUM> link is greater than or equal to the size of the fragmented frame <NUM>.

According to some embodiments, the fragmentation parameters (e.g., frame size) cannot be changed. If the length of the MPDU carrying the remaining fragmented frame is greater than the Maximum MPDU Length capability of another link, the remaining fragmented frame cannot be transmitted on that link. Moreover, when an initial transmission of a frame is not fragmented, any retransmission of that frame also cannot be fragmented. Accordingly, if the MPDU length of the initial transmission is greater than the Maximum MPDU Length capability of another link, the frame cannot be retransmitted on that link.

<FIG> is a block diagram of an exemplary wireless computer system <NUM> for performing multi-link operations using a virtual MAC address for setting the RA or TA parameter value in a MAC header of a respective A-MSDU according to embodiments of the present invention. Multi-band wireless AP <NUM> includes multiple AP instances AP1 <NUM>, AP2 <NUM>, and AP3 <NUM> capable of performing multi-band operations, including transmitting or receiving frames simultaneously over multiple bands. Multi-band wireless STA <NUM> includes multiple STA instances STA1 <NUM>, STA2 <NUM>, and STA3 <NUM> capable of performing multi-band operations, including sending or receiving frames simultaneously over multiple bands. AP1 <NUM> and STA1 <NUM> communicate over a <NUM> wireless link (Link <NUM>), AP2 <NUM> and STA2 <NUM> communicate over a <NUM> wireless link (Link <NUM>), and AP3 <NUM> and STA1 <NUM> communicate over a <NUM> wireless link (Link <NUM>).

Logical Link Control (LLC) sublayers <NUM> and <NUM>, are coupled to Multi-band AP <NUM> and multi-band STA <NUM>, respectively. LLC sublayer <NUM> is assigned a virtual MAC address V_MAC_ADDRAP and LLC sublayer <NUM> is assigned a virtual MAC address V_MAC_ADDRSTA. The LLC sublayers <NUM> and <NUM> communicate with the multiple AP and STA instances (e.g., MAC/PHY entities) using the interface associated with the respective Virtual MAC address. Multi-band wireless AP <NUM> includes MAC/PHY entities configured as wireless AP instances <NUM>, <NUM>, and <NUM> that operate over different bands, and multi-band wireless STA <NUM> includes MAC/PHY entities configured as wireless STA instances <NUM>, <NUM>, and <NUM> that operate over the different bands. As depicted in <FIG>, the value of the virtual MAC addresses is assigned to correspond to a MAC address of one of the MAC/PHY entities, such as MAC_ADDR4 associated with AP1 <NUM> (AP side) and MAC_ADDR1 associated with STA1 <NUM> (STA side).

When wireless multi-band STA <NUM> sends MPDUs on multiple links, the receiver address (RA) and transmitter address (TA) values of the MAC header of the respective A-MSDU are decided after the STA obtains the TXOP. In this example, the MAC address associated with the MAC/PHY entity of the link on which wireless multi-band STA <NUM> obtains the TXOP is used to set the RA and the TA parameter values of the MAC header of the frame to be transmitted over Link3. In order to send frames to the multi-band AP <NUM> over Link <NUM> that will be routed to the interface of LLC Sublayer <NUM>, the multi-band STA <NUM> sets the RA field in the MAC header of the A-MSDU to MAC_ADDR6 and the TA field in the MAC header of the A-MSDU to MAC_ADDR3.

Under existing approaches to frame aggregation, the DA and SA parameter values in the sub-frame header of A-MSDU sub-frames should be set to the same RA and the TA parameter values in the MAC header of the A-MSDU. However, because the MSDU aggregation is performed before MPDU generation, the DA and SA in the A-MSDU sub-frame headers must be determined independently for the specific link on which the TXOP is obtained in a multi-link operation. Accordingly, in the example of <FIG>, the SA parameter value of the A-MSDU sub-frame header is set to virtual mac address V_MAC_ADDRSTA (corresponding to MAC_ADDR1), and the DA parameter value of the A-MSDU sub-frame header is set to virtual mac address V_MAC_ADDRAP (corresponding to MAC_ADDR4). It is to be appreciated that the virtual MAC address can be set to any of the MAC address of the MAC/PHY entities. In this way, a received frame is delivered to the LLC sublayer interface using the virtual MAC address, and the LLC sublayer can pass the received data to a higher sublayer (e.g., network layer).

According to some embodiments, each MAC entity of the recipient STA can have different A-MSDU capabilities and configurations. For example, each MAC entity can support a different number of MSDUs that can be carried in an A-MSDU, different maximum MPDU lengths that the STA is capable of receiving, and different maximum A-MSDU lengths that the STA is capable of receiving. Therefore, according to some embodiments, MSDU aggregation is performed to satisfy the A-MSDU capability requirements of all MAC entities of the recipient device. For example, when a recipient STA can receive n and m MSDUs in an A-MSDU sent from the first link and the second link, respectively, the transmitting multi-band STA shall not aggregate more than min (n, m) MSDUs in the A-MSDU to satisfy the capability requirements of both the first link and the second link.

In some cases, satisfying the A-MSDU capability requirements for all MAC entities of the recipient wireless STA can lead to degraded performance. According to some embodiments, to maintain performance levels of the multi-link operation, A-MSDU capability requirements (e.g., maximum number of MSDUs in an A-MSDU, maximum MPDU length, and maximum A-MSDU length) are only satisfied for a specific link or set of links when aggregating the A-MSDU. The specific links that satisfy the selected capability requirements can be referred to as an "eligible link set. " When the multi-band STA schedules MPDUs after obtaining a TXOP, the MPDU containing an A-MSDU is limited to transmittion using the eligible link set for transmitting the A-MSDU. For example, a transmitting multi-band STA can aggregate MSDUs while meeting the A-MSDU capability requirements a first link (Link1) only. In this case, the transmitting multi-band STA can schedule the MPDU containing the corresponding A-MSDU on the first link only (Link1). In another example, the transmitting multi-band STA aggregates MSDUs while meeting the A-MSDU capability requirements for both the first link and a second link (Link2). In this case, the transmitting multi-band STA can schedule the MPDU containing the corresponding A-MSDU on both the first link and the second link (Link1 + Link2) which are included in the eligible link set.

According to some embodiments, MSDUs belonging to specific a TID are allocated to a specific link or set of links. In this case, the multi-band STA satisfies a set of A-MSDU capability requirements (e.g., Max Number of MSDUs in A-MSDU, Maximum MPDU Length, and Maximum A-MSDU Length) for at least one of the specific links when MSDUs are aggregated to transmit the MSDUs belonging to the TID. The recipient STA can also declare a separate Multi-Band specific A-MSDU capability requirement or set of requirements. The recipient STA can announce its A-MSDU capability requirements in a multi-link setup frame during a multi-link setup negotiation phase, and the transmitting multi-band STA can aggregate the MSDUs of the TID to satisfy the set of the Multi-Band specific A-MSDU capability requirements indicated in the multi-link setup frame.

<FIG> is a block diagram of an exemplary A-MSDU frame format <NUM> according to embodiments of the present invention. In <FIG>, exemplary A-MSDU subframes <NUM> - n (<NUM>) are depicted. Exemplary A-MPDU subframe n (<NUM>) includes MSDU field <NUM>, A-MSDU subframe header <NUM> including DA field <NUM> and SA field <NUM> for setting the destination address and sources addresses of the A-MSDU transmission, respectively, and a length field <NUM> indicating the length in bits of MSDU field <NUM>. The MSDU frame format <NUM> includes <NUM> bytes for padding <NUM>. The exemplary MSDU frame format <NUM> can be used to implement embodiments of the present invention, for example, to perform EHT multi-band A-MSDU operations, such as transmission of A-MSDUs and/or fragmented frames simultaneously over multiple bands. The A-MSDU frame can be carried in a PSDU, for example.

<FIG> is a flow chart of an exemplary computer implemented process <NUM> for transmitting data in a multi-link operation using an A-MSDU/MSDU according to embodiments of the present invention.

At step <NUM>, capabilities of a receiving device are determined. Step <NUM> can include receiving an indication of capabilities from the receiving device. The capabilities can include support for multi-link fragmentation, for example. The capabilities can also include MDPU capability requiremetns, such as MPDU length capability, maximum Number of MSDUs in an A-MSDU, etc..

At step <NUM>, an MPDU length capability of the first wireless link and an MPDU length capability the second wireless link are determined. The MPDU length capability can be associated with the transmitting device or the receiving device. The determining can be made according to an indication of capabilities transmitted by the receiving device, for example.

At step <NUM>, an A-MSDU/MSDU is fragmented into a first fragmented frame and a second fragmented frame according to the MPDU length capabilities.

At step <NUM>, the first fragmented frame and the second fragmented frame of the A-MSDU/MSDU are transmitted to the receiving device simultaneously in the multi-link operation over the wireless network.

<FIG> is a flow chart of an exemplary computer implemented process <NUM> for uplink transmission of data using virtual MAC addresses assigned to LLC sublayer interfaces by a transmitting device according to embodiments of the present invention. The wireless STA can be a MLD non-AP STA and the wireless AP can be a MLD AP.

At step <NUM>, a TXOP is received on a first wireless link at a first wireless STA instance of the transmitting device.

At step <NUM>, an SA field of one or more A-MSDU sub-frame headers of the A-MSDU are set according to a virtual MAC address of an LLC sublayer interface of the transmitting device.

At step <NUM>, a DA field of the one or more A-MSDU sub-frame headers of the A-MSDU are set according to a virtual MAC address of an LLC sublayer interface of the receiving device for delivering the A-MSDU to an LLC sublayer of the receiving device.

At step <NUM>, a TA field of a MAC header of the A-MSDU is set according to a MAC address of the first wireless STA instance.

At step <NUM>, an RA field of the MAC header of the A-MSDU is set to a MAC address of a wireless AP instance of the receiving device.

Steps <NUM>-<NUM> can be repeated for a second A-MSDU to be transmitted over a second wirelessl link in order to transmit multiple frames to the receiving device simultaneously in a multi-link operation. For example, another TXOP can be receieved on the second wireless link at a second wireless STA instance of the transmitting device. An SA field of an A-MSDU sub-frame header of the second A-MSDU is set according to the virtual MAC address of the LLC sublayer interface of the transmitting device, and the DA field of the A-MSDU sub-frame header of the second A-MSDU is set according to the virtual MAC address of the LLC sublayer interface of the receiving device for delivering the A-MSDU to an LLC sublayer of the receiving device. The TA field of a MAC header of the second A-MSDU is set according to a MAC address of a second wireless STA instance of the transmitting device, and an RA field of the MAC header of the second A-MSDU is set to a MAC address of a second wireless AP instance of the receiving device.

At step <NUM>, the A-MSDU is transmitted by the transmitting device to the receiving device using the virtual MAC addresses in the AMPDU sub-frame headers over the first wireless link. Step <NUM> can also include transmitting the second A-MSDU to the receiving device using the virtual MAC addresses over the second wireless link concurrently with the transmission of the A-MSDU over the first wireless link in a multi-link operation.

<FIG> is a flow chart of an exemplary computer implemented process <NUM> for downlink transmission of data using virtual MAC addresses assigned to LLC sublayer interfaces by a transmitting device according to embodiments of the present invention. The wireless STA can be a MLD non-AP STA and the wireless AP can be a MLD AP.

At step <NUM>, an SA field of one or more A-MSDU sub-frame headers of the A-MSDU are set according to a virtual MAC address of an LLC sublayer interface of the the MLD AP.

At step <NUM>, a DA field of the one or more A-MSDU sub-frame headers of the A-MSDU are set according to a virtual MAC address of an LLC sublayer interface of the MLD non-AP STA for receiving the A-MSDU to an LLC sublayer of the receiving device.

At step <NUM>, a TA field of a MAC header of the A-MSDU is set according to a MAC address of a first wireless AP instance of the wireless MLD AP.

At step <NUM>, an RA field of the MAC header of the A-MSDU is set to a MAC address of a wireless STA instance of the MLD non-AP STA.

Steps <NUM>-<NUM> can be repeated for a second A-MSDU to be transmitted over a second wireless link in order to transmit multiple frames to the receiving device simultaneously in a multi-link operation as described above.

At step <NUM>, the A-MSDU is transmitted by the MLD AP to the MLD non-AP STA using the virtual MAC addresses in the AMPDU sub-frame headers over the first wireless link. Step <NUM> can also include transmitting a second A-MSDU to the receiving device using the virtual MAC addresses over the second wireless link concurrently with the transmission of the A-MSDU over the first wireless link in a multi-link operation.

Embodiments of the present invention are drawn to electronic systems that perform multi-link operations in a wireless network. The multi-link operations can include aggregating MPDUs and transmitting or receiving A-MSDUs over multiple wireless links simultanesouly, such as the exemplary A-MSDU sub-frame depicted in <FIG>. The aggregating can include setting parameter values of an A-MSDU sub-frame header to correspond to a virtual MAC address of an LLC sublayer and can be performed according to capability requiremetns of a transmitting device and/or a recievign device. The following discussion describes one such exemplary electronic system or computer system that can be used as a platform for implementing embodiments of the present invention. The exemplary computer system <NUM> can be a wireless access point or a wireless station, for example.

In the example of <FIG>, the exemplary computer system or wireless device includes a central processing unit (such as a processor or a CPU) <NUM> for running software applications and optionally an operating system. Read-only memory <NUM> and random access memory <NUM> store applications and data for use by the CPU <NUM>. Data storage device <NUM> provides non-volatile storage for applications and data and may include fixed disk drives, removable disk drives, flash memory devices, and CD-ROM, DVD-ROM or other optical storage devices. The optional user inputs <NUM> and <NUM> comprise devices that communicate inputs from one or more users to the computer system <NUM> (e.g., mice, joysticks, cameras, touch screens, and/or microphones).

A communication or network interface <NUM> includes a plurality of transceivers and allows the computer system <NUM> to communicate with other computer systems, networks, or devices via an electronic communications network, including wired and/or wireless communication and including an Intranet or the Internet (e.g., <NUM> wireless standard). The network interface <NUM> can perform multi-link operations (e.g., multi-link packet scheduling and channel access) using multiple wireless links to improve network throughput, for example. According to embodiments of the present invention, the communication or network interface <NUM> can operate multiple transceivers simultaneously. The communication or network interface <NUM> and can include a multi-band (e.g., dual-band) interface that can operate in multiple bands simultaneously, such as <NUM>, <NUM>, and/or <NUM>.

The optional display device <NUM> may be any device capable of displaying visual information in response to a signal from the computer system <NUM> and may include a flat panel touch sensitive display, for example, and may be remotely disposed. The components of the computer system <NUM>, including the CPU <NUM>, memory <NUM>/<NUM>, data storage <NUM>, user input devices <NUM>, and graphics subsystem <NUM> may be coupled via one or more data buses.

Some embodiments may be described in the general context of computer-executable instructions, such as program modules, executed by one or more computers or other devices.

Claim 1:
A method of transmitting data to a receiving device by a transmitting device in a multi-link operation over a wireless network, wherein the transmitting device is a multi-link wireless station, in the following also referred to as STA, comprising a plurality of wireless STA instances and the receiving device is a multi-link wireless access point, in the following also referred to as AP, comprising a plurality of wireless AP instances, the method comprising:
obtaining a transmission opportunity, in the following also referred to as TXOP, for transmitting an aggregate media access control, in the following also referred to as MAC, service data unit, in the following also referred to as A-MSDU, on a first wireless link at a first wireless station, in the following also referred to as STA, instance of the plurality of wireless STA instances of the transmitting device (<NUM>);
setting a source address , SA, field of an A-MSDU sub-frame header of an A-MSDU sub-frame included in the A-MSDU according to a virtual MAC address of an logical link control, in the following also referred to as LLC, sublayer interface of the transmitting device (<NUM>);
setting a destination address, DA, field of the A-MSDU sub-frame header of the A-MSDU sub-frame included in the A-MSDU according to a virtual MAC address of an LLC sublayer interface of the receiving device for delivering the A-MSDU to an LLC sublayer of the receiving device (<NUM>); and
transmitting the A-MSDU to the receiving device over the first wireless link (<NUM>),
wherein each wireless STA instance of the plurality of wireless STA instances and each wireless AP instance of the plurality of wireless AP instances is associated with a respective MAC address, and
wherein the virtual MAC address of the LLC sublayer interface of the transmitting device corresponds to a MAC address of a wireless STA instance of the plurality of wireless STA instances, and the virtual MAC address of the LLC sublayer of the receiving device corresponds to a MAC address of a wireless AP instance of the plurality of wireless AP instances of the receiving device.