CN113207189B - Data transmission method - Google Patents

Abstract

The invention provides a data transmission method. According to one embodiment, first and second trigger frames are received from a wireless Access Point (AP) at a wireless Station (STA) over first and second wireless links, respectively. When a difference between an end time of a data frame transmitted in response to the first trigger frame and an end time of a data frame transmitted in response to the second trigger frame is greater than a predetermined value, the first and second data frames are transmitted in response to the first trigger frame and the second trigger frame over the first and second wireless links, respectively, to prevent interference.

Description

Data transmission method

[ field of technology ]

Embodiments of the present invention relate generally to the field of wireless communications. More particularly, embodiments of the present invention relate to systems and methods for triggered uplink access for multiple link operation in a wireless network.

[ background Art ]

Modern electronic devices typically transmit 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., 2.4GHz, 5GHz, and 6 GHz). In most cases, wireless devices can only communicate on a single frequency band at a time. For example, older and low-power devices, such as battery-powered devices, typically operate in the 2.4GHz band. Newer devices and devices requiring greater bandwidth typically operate in the 5GHz band. The availability of the 6GHz band is a recent development that can provide higher performance, lower latency and faster data rates.

However, in some cases, the use of a single frequency band may not meet the bandwidth requirements of certain devices. Accordingly, some evolving methods for wireless communications increase communication bandwidth by operating simultaneously (conclusively) on multiple frequency bands (technically known as link aggregation or multiple link operation).

When wireless devices simultaneously transmit and receive data in multiple link operation, in-device coexistence (in-device coexistence, abbreviated IDC) interference can result in substantial performance loss between multiple wireless links. IDC interference caused by simultaneous transmission and reception in the 2.4GHz band and the 5GHz band is typically negligible. However, IDC interference caused by simultaneous transmission and reception in the 5GHz band and the 6GHz band seriously affects performance and causes frequent packet (packet) loss.

Thus, to avoid IDC interference, the wireless device should not send and receive frames on multiple links simultaneously. However, it is currently difficult to synchronize transmissions over multiple wireless links to ensure that the wireless device does not send and receive frames over multiple wireless links simultaneously, as the wireless device cannot easily determine when the transmission of the frames ends. As a result, the multi-link operation is subject to IDC interference, which can severely impact the performance of overlapping (misaligned) frame transmissions over the multi-radio link.

Uplink transmissions (uplink transmission, abbreviated UL) involving multiple non-Access Point (AP) Stations (STAs) transmitting simultaneously to an AP station (called triggered uplink access (Triggered Uplink Access, abbreviated TUA)) are introduced in the IEEE 802.11ax standard. This mechanism uses an 802.11MAC Frame called a Trigger Frame (Trigger Frame) sent by the AP station. The HE-enabled AP station sends a trigger frame to initiate an orthogonal frequency division multiple access (orthogonal frequency division multiple access, abbreviated OFDMA) or multi-user multiple-input multiple-output (MU-MIMO) transmission prior to transmissions by other non-AP stations. The trigger frame identifies non-AP stations that participate in UL MU transmissions and allocates Resource Units (RUs) to the non-AP stations. Each non-AP station receiving the trigger frame transmits a trigger-based (abbreviated TB) entity layer consistency procedure (physical layer conformance procedure, abbreviated PLCP) Protocol Data Unit (PPDU) back to the AP using the RU assigned to the respective station. Accordingly, there is a need for a method of performing constraint (constraint) multiple link operation using triggered uplink access that can prevent IDC interference caused by transmission of a TB PPDU while a trigger frame has been received on another wireless link of a non-AP STA.

[ invention ]

Accordingly, embodiments of the present invention provide a method for constrained multi-link operated TB uplink transmission that substantially prevents interference caused by a wireless device (e.g., a wireless STA or AP) transmitting and receiving data (e.g., a PPDU) simultaneously.

According to one embodiment, a method for multi-link trigger based data transmission in a wireless network is disclosed. The method includes transmitting a first trigger frame from a first affiliated wireless Access Point (AP) of a multi-band wireless AP to a wireless Station (STA) over a first wireless link, wherein the first trigger frame includes a Carrier Sense (CS) required field (required field) having a value of 1, determining that a second affiliated wireless AP of the scheduled multi-band wireless AP transmits a second trigger frame to the wireless STA over a second wireless link, and transmitting the second trigger frame from the second affiliated wireless AP to the wireless STA over the second wireless link when a difference between a start time of a Physical Layer Coherence Procedure (PLCP) protocol data unit (PPDU) transmitted by the wireless STA in response to the first trigger frame and an end time of the second trigger frame is equal to or greater than a predetermined margin.

According to some embodiments, the predetermined margin is determined from a calculation of asifstime+asignalxextension-arxtturnaroundtime.

According to some embodiments, the predetermined margin is 12 μs.

According to some embodiments, the predetermined margin is determined according to requirements of the wireless AP.

According to some embodiments, the first wireless link comprises a 6GHz wireless link and the second wireless link comprises a 5GHz wireless link.

According to various embodiments, a method of data transmission based on multiple link triggers in a wireless network is disclosed. The method includes receiving a first trigger frame and a second trigger frame from a wireless Access Point (AP) at a wireless Station (STA) over a first wireless link and a second wireless link, respectively, calculating a difference between an end time of a first Physical Layer Coherence Procedure (PLCP) protocol data unit (PPDU) carrying the first trigger frame and an end time of a second PPDU carrying the second trigger frame, and transmitting the first data frame and the second data frame over the first wireless link and the second wireless link, respectively, in response to the first trigger frame and the second trigger frame when the difference between the end time of the first PPDU and the end time of the second PPDU is greater than a predetermined value.

According to some embodiments, the predetermined value is determined according to a short interframe space (short interframe space, abbreviated SIFS) - (10% x aSlotTime), and wherein aSlotTime is determined according to a specification of the wireless network.

According to some embodiments, the predetermined value is selected from the following values: 4 μs,8 μs and 16 μs.

According to some embodiments, the first PPDU and the second PPDU are formatted using one of: non HT, HT, VHT, HE and EHT formats.

According to some embodiments, the method includes adjusting an end time of the first PPDU by adjusting a MAC pad of the first PPDU.

According to some embodiments, the method includes adjusting an end time of the first PPDU by adjusting a PHY pad of the first PPDU.

According to some embodiments, the method includes adjusting an end time of the first PPDU by adjusting a PE frame of the first PPDU.

According to some embodiments, the method comprises: the first wireless link comprises a 6GHz wireless link and the second wireless link comprises a 5GHz wireless link.

According to some embodiments, the method includes adjusting an end time of the first PPDU to substantially mitigate in-device coexistence interference.

According to another embodiment, a method of data transmission based on multi-link triggering in a wireless network is disclosed. The method includes receiving a first trigger frame and a second trigger frame from a wireless Access Point (AP) at a wireless Station (STA) over a first wireless link and a second wireless link, respectively, transmitting a first data frame and a second data in response to the first trigger frame and the second trigger frame transmitted to the wireless AP over the first wireless link and the second wireless link, respectively, and receiving an Acknowledgement (ACK). The transmitting includes calculating a difference between an end time of a first Physical Layer Coherence Procedure (PLCP) protocol data unit (PPDU) carrying a first data frame and an end time of a second PPDU carrying a second data frame, and setting an UL length field according to the difference between the end time of the first PPDU and the end time of the second PPDU to prevent interference leakage between the first wireless link and the second wireless link when receiving the ACK.

According to some embodiments, the UL length field of the first PPDU is set such that a difference between an end time of the first PPDU and an end time of the second PPDU is greater than SIFS- (10% ×aslottime), wherein aSlotTime is determined according to a specification of the wireless AP. According to some embodiments, setting the UL length field of the first PPDU prevents transmission of the second data frame during reception of the ACK.

According to some embodiments, the first wireless link comprises a 6GHz wireless link and the second wireless link comprises a 5GHz wireless link. According to some embodiments, the method includes performing PHY padding on the ACKs.

According to some embodiments, the method includes performing MAC padding on the ACK.

[ description of the drawings ]

Various embodiments of the present disclosure will be described in detail, by way of example, with reference to the following drawings, in which:

fig. 1 is a block diagram of an exemplary synchronized multilink transmission according to an embodiment of the present invention.

Fig. 2 is a block diagram depicting an exemplary limited multiple link operation using a triggered uplink access that results in IDC interference caused by a wireless STA transmitting and receiving data simultaneously, in accordance with an embodiment of the present invention.

Fig. 3 is a block diagram of an exemplary limited multiple link operation using a triggered uplink access for preventing IDC interference caused by a wireless STA transmitting and receiving data simultaneously, in accordance with an embodiment of the present invention.

Fig. 4 is a block diagram of an exemplary limited multi-link operation using triggered uplink access, which results in interference leakage due to a wireless STA sensing a channel during SIFS, in accordance with an embodiment of the present invention.

Fig. 5 is a block diagram of an exemplary limited multi-link operation using triggered uplink access for preventing interference leakage due to a wireless STA sensing a channel during SIFS in accordance with an embodiment of the present invention.

Fig. 6 is a block diagram of an exemplary limited multiple link operation using triggered uplink access that results in reception errors due to interference leakage between wireless links in accordance with an embodiment of the present invention.

Fig. 7 is a block diagram of an exemplary limited multiple link operation using triggered uplink access to prevent interference leakage in accordance with an embodiment of the present invention.

Fig. 8 is a flowchart illustrating an exemplary sequence of computer implemented steps for performing limited multi-link triggered uplink access to prevent IDC interference in accordance with an embodiment of the present invention.

Fig. 9 is a flowchart of an exemplary sequence of computer implemented steps for performing constrained multi-link triggered uplink access to prevent wireless links from entering a busy state due to interference leakage, in accordance with an embodiment of the present invention.

Fig. 10 is a flowchart of an exemplary sequence of computer implemented steps for performing constrained multi-link triggered uplink access to prevent interference leakage between wireless links, in accordance with an embodiment of the present invention.

FIG. 11 is a block diagram depicting an exemplary computer system platform upon which embodiments of the invention may be implemented.

[ detailed description ] of the invention

Reference will now be made in detail to several embodiments. While the subject matter will be described in conjunction with alternative embodiments, it will be understood that they are not intended to limit the claimed subject matter to these embodiments. On the contrary, the claimed subject matter is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the claimed subject matter as defined by the appended claims.

Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the claimed subject matter. However, it will be recognized by one skilled in the art that the embodiments may be practiced without these specific details or with equivalents thereof. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects and features of the subject matter.

Portions of the following detailed description are presented and discussed in terms of methods. Although steps and sequences thereof are disclosed herein in the accompanying figures (e.g., figures 8-10) that describe the operation of the method, such steps and sequences are exemplary. Embodiments are well suited to performing various other steps or variations of the steps recited in the flowcharts of the figures herein, and in a different order than 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. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the following discussions, it is appreciated that throughout the discussion, terms such as "accessing," "configuring," "coordinating," "storing," "transmitting," "retransmitting," "authenticating," "identifying," "requesting," "reporting," "determining," or the like, refer to the operation and processing 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.

Synchronization of EHT multi-link triggered uplink access

As used herein, the term "EHT" may generally refer to a new generation of wireless communications (Wi-Fi), referred to as an Extremely High Throughput (EHT), and is defined in accordance with the IEEE 802.11be standard. The term Station (STA) generally refers to an electronic device capable of transmitting and receiving data over Wi-Fi, which device does not operate as an Access Point (AP).

Multiple link operation may provide higher network throughput and higher network flexibility than conventional wireless communication techniques. Embodiments of the present invention substantially prevent interference caused by simultaneous transmission and reception of data in limited multiple link operation of a wireless network. Multiple link operations may be performed between Multiple Link Devices (MLDs) including multiple dependent STAs (non-AP STAs or AP-STAs) operating on different wireless links.

With respect to fig. 1, an exemplary wireless communication system 100 is depicted that includes a multi-band cooperative AP105 and a multi-band cooperative STA 155, in accordance with an embodiment of the present invention. The multiband cooperative AP105 and multiband cooperative STA 155 are examples of MLD. The multi-band cooperative AP105 includes a 5GHz transceiver 110 and a 2.4GHz transceiver 115. According to embodiments of the present invention, the multi-band cooperative AP105 may also use other types of transceivers operating on different frequency bands, such as 6GHz and above. Transceivers 110 and 115 of AP105 exchange data and information with a collaboration management unit 120 that coordinates information sent and/or received by transceivers 110 and 115. AP105 may be considered to include two AP instances or "accessory" APs to use 5GHz transceiver 110 and 2.4GHz transceiver 115.

The multi-band cooperative STA 155 includes a 5GHz transceiver 160 and a 2.4GHz transceiver 165. Multi-band cooperative STAs 155 in accordance with some embodiments of the present invention may also use other types of transceivers that operate over different frequency bands, such as 6GHz and beyond. The transceivers 160 and 165 of the STA 155 exchange data and information with the cooperation management unit 170, and the cooperation management unit 170 coordinates the information transmitted and received by the transceivers 160 and 165 using 5GHz band wireless communication and 2.4GHz band wireless communication, respectively, although any well-known wireless communication band (e.g., 6 GHz) may be used. STA 155 may be considered to include two STA instances or "dependent" STAs to communicate using 5GHz transceiver 160 and 2.4GHz transceiver 165.

The multi-band cooperative AP105 and the multi-band cooperative STA 155 have simultaneous transmission and reception capabilities for communicating using different wireless bands. Transmitters operating on different frequency bands may use joint or intentional transmissions for independent clear channel assessment (clear channel assessments, abbreviated CCA). Further, full duplex communication may be enabled through independent multi-band operation using FDD mode.

Transmitting frames simultaneously using multiple frequency bands by STA 155 may mitigate delays and improve peak throughput (peak throughput) of STA 155. However, in some cases, transmitting frames using multiple frequency bands simultaneously may reduce the performance of a basic service set (basic service set, abbreviated BSS) including STA 155. Thus, the AP105 may control which STAs are granted multi-band channel access, and the access may be terminated by the AP at any time, e.g., based on changing network conditions or requirements.

Depending on certain conditions such as traffic load, non-AP STAs may use fewer than all supported/available links to reduce power consumption. In addition, the non-AP STA may apply independent power management for each link, and the AP may provide TID-to-link (TID-to-link) mapping information for each link. According to a quality of service (Quality of Service, abbreviated QoS) policy of a Basic Service Set (BSS), an AP may allocate traffic to different links according to traffic type (e.g., voice, video, data, etc.). For example, frames belonging to a first traffic identifier (first Traffic Identifier, abbreviated TID 1) may be allocated to a first link and frames belonging to a second traffic identifier (second Traffic Identifier, abbreviated TID 2) may be allocated to a second link. In this case, the AP may provide TID-to-link mapping information to wireless STAs for both links, with some data being sent only on the first link and other data being sent only on the second link.

Data transmitted over a first wireless link (e.g., a 5GHz wireless link provided by 5GHz transceiver 110 or 160) may be retransmitted over a different wireless link. For example, if a data transmission over a 5GHz wireless link is not successfully sent (e.g., no acknowledgement is received), the data may be retransmitted over the 2.4GHz wireless link provided by the 2.4GHz transceivers 115/165. When an unintended channel switch to another channel occurs, or when delay-sensitive packets (delay-sensitive packets) are transmitted over multiple links, data may be retransmitted over a second link. Further, according to embodiments of the present invention, a data transmission (e.g., a PPDU) may be initially encoded for transmission over a first wireless link (e.g., a 2.4GHz or 5GHz wireless link) and retransmitted data may be prepared for transmission for retransmission of encrypted data in a multi-link environment.

Fig. 2 depicts an exemplary limited multi-link operation 200 using triggered uplink access that results in IDC interference caused by a wireless STA (e.g., a non-AP wireless STA or a multi-link device (e.g., MLD)) either simultaneously occurring or accepting data, in accordance with an embodiment of the present invention. In fig. 2, the wireless AP205 sends a trigger frame 215 to the wireless STA 210 to request an uplink response frame over the 5GHz wireless link 220. The AP205 sends a trigger frame 225 to the wireless STA 210 to request an uplink response frame over the 6GHz wireless link 230 before transmission of the trigger frame 215 to the wireless STA 210 is completed. Before the STA 210 has completed receiving the trigger frame 225, the wireless STA 210 transmits an EHT TB PPDU235 (in response to the trigger frame 215), resulting in IDC interference 240 caused by the simultaneous transmission and reception of data in multiple link operation. In the example of fig. 2, the multi-band AP205 is an MLD that includes a plurality of accessory APs (e.g., a first accessory AP operating on the 6GHz link 220 and a second accessory AP operating on the 5GHz link 230) and the multi-band STA 210 is an MLD that includes a plurality of accessory STAs (e.g., a first accessory STA operating on the 6GHz link 220 and a second accessory STA operating on the 5GHz link 230).

Fig. 3 depicts an exemplary limited multiple link operation 300 using triggered uplink access to prevent IDC interference caused by a multi-band wireless STA transmitting and receiving data simultaneously, in accordance with an embodiment of the present invention. In fig. 3, the multi-band wireless AP 305 transmits a trigger frame 315 to the multi-band wireless STA 310 over the 5GHz wireless link 320 to request an uplink response frame. Before the transmission of the trigger frame 315 to the wireless STA 310 is completed, the AP 305 transmits a trigger frame 325 to the wireless STA 310 over the 6GHz wireless link 330 to request an uplink response. Before STA 310 has completed receiving trigger frame 325, wireless STA 310 transmits a TB PPDU 335 (in response to trigger frame 315), resulting in IDC interference. According to the example of fig. 3, when the difference between the end times of the respective PPDUs (e.g., trigger frames 315 and 325) transmissions is less than a short inter-frame spacing (SIFS) - (10% ×aslottime), the wireless AP 305 may schedule the PPDU carrying the trigger frames to the STA 310, where aSlotTime is a fixed/predefined value. As shown in fig. 3, because minimum inter-frame space 340 is not less than SIFS 365, transmission 315 and reception 335 of AP 305 advantageously do not overlap. For example, the start and end time alignment in fig. 3 may be implemented using MAC padding 345, PHY padding 350, and/or PE 355. SIFS time may be calculated as: sifs=asifstime+asignalxension. According to some embodiments, aSIFSTime is fixed at 10 μs at 5GHz and 16 μs at 2.4GHz, and the value of asignalxension is 0 μs for the 5GHz band and 6 μs for the 2.4GHz band. The requested PPDU may be transmitted in any well-known PPDU format, such as non-HT, HT, VHT, HE, EHT, etc.

According to one embodiment, the start time and end time of the multiple link transmission are synchronized within a margin (margin) equal to sifstime+aSignalExtension using, for example, MAC padding, PHY padding, and/or Packet Extension (PE).

According to some embodiments, the margin is fixed at 16 μs. Specifically, the value of aSIFSTime is 10 μs for the 2.4GHz band and 16 μs for the 5GHz band; for the 2.4GHz band, the value of aSignalExtension is 6 μs; for the 5GHz band, 0 μs.

With respect to fig. 4, an exemplary constrained multi-link operation 400 for triggered uplink access is depicted that results in interference leakage caused by a wireless STA sensing channel during SIFS, in accordance with an embodiment of the present invention. In fig. 4, wireless multiband AP 405 sends trigger frame 415 to multiband wireless STA 410 to request an uplink response frame on 5GHz wireless link 420 and trigger frame 425 on 6GHz wireless link 430. The TB PPDU 435 is transmitted by the wireless STA 410 (in response to the trigger frame 415), and the difference between the end time of the trigger frame 415 and the start time of the TB PPDU 435 is less than SIFS- (10% ×aslottime). The STA 410 senses the 6GHz channel 430 during SIFS 440, changing Carrier Sense (CS) at 5GHz when IDC interference is greater than an Energy Detection (ED) threshold. In this case, when the CS required field of the trigger frame 425 is set to 1, the STA 410 will not respond to the trigger frame 425.

With respect to fig. 5, an exemplary limited multi-link operation 500 is shown for preventing interference leakage caused by a wireless STA sensing channels during SIFS using triggered uplink access, in accordance with an embodiment of the present invention. In fig. 5, wireless AP 505 sends trigger frame 515 to wireless STA 510 to request an uplink response frame on 5GHz wireless link 520 and trigger frame 525 on 6GHz wireless link 530. The TB PPDU 535 is transmitted wirelessly by STA 510 (in response to trigger frame 515). The Carrier Sense (CS) required field of trigger frames 515 and 525 is set to 1. Thus, prior to transmission, the AP 505 determines whether the difference 540 between the end time of the trigger frame 525 and the start time of the TB PPDU 535 is greater than or equal to aCCATime. If the difference 540 is greater than or equal to the aCCATime, the STA 510 may perform channel sensing during SIFS and respond with the requested TB PPDU 535 without causing interference. Otherwise, if the difference 540 between the end time of the trigger frame 525 and the start time of the TB PPDU 535 is less than the atcatime, the transmission is restricted. According to some embodiments, the aCCATime is 4 μs or 8 μs. According to some embodiments, the aCCATime of the wireless STA is signaled by the wireless STA to the associated wireless AP.

According to some embodiments, if the TB PPDUs transmitted over different links are not completely synchronized on the OFDM symbol level, the wireless STA does not respond to a trigger frame that sets the CS required field to 1. According to some embodiments, the STA reports any interference leakage from the first link, which causes the CS state of the second link to switch to a busy state (when the interference is greater than the ED threshold). For concurrent TB PPDU transmissions on the first link and the second link, the AP provides OFDM symbol alignment between the PPDU containing the trigger frame and the responsive TB PPDU. In other words, the end time of the PPDU containing the trigger frame is aligned within the OFDM symbol duration (e.g., 4 us), and thus the start time of the responding TB PPDU is also aligned within the OFDM symbol duration (e.g., 4 us).

According to some embodiments, when the wireless AP cannot meet the synchronization requirement (e.g., the difference between the end times of the multiple PPDUs is less than SIFS- (10% ×aslottime)), the wireless AP does not trigger multiple TB PPDU transmissions requiring CS at the same time. Therefore, the wireless AP cannot simultaneously transmit more than one PPDU containing a trigger frame with the required CS set to 1. However, when one trigger frame includes a CS required field set to 1 and another trigger frame includes a CS required field set to 0, the AP may simultaneously transmit more than one PPDU including the trigger frame.

In some cases, the TB PPDUs transmitted on the multiple links use different TXVECTOR parameters (e.g., GI or LTF types) making it difficult to synchronize the start time and end time of transmissions on the multiple links. To relax the requirements for multi-link operation, the start time and end time of transmissions on multiple links may be synchronized at the wireless STA within a margin of (asifstime+asignalxension)/2 using MAC padding, PHY padding, or Packet Extension (PE). The transmission opportunity (TXOP) holder may adjust an interframe space (IFS) between SIFS and sifs+sifs/2 such that the IFS is different for each link. In these embodiments, if the wireless AP determines that the wireless STA is likely to transmit frames on the first wireless link after the trigger frame requested during SIFS, the AP does not transmit a trigger frame with a desired CS equal to 1 to the wireless STA on the second link.

According to some embodiments, when PPDUs from STAs associated with the same wireless STA are scheduled to transmit within a predetermined margin after receiving a PPDU containing a trigger frame, a wireless AP that performs TB multi-link access is restricted from transmitting a trigger frame with a CS required subfield set to 1 to the wireless STA. According to some embodiments, the margin is determined according to (asifstime+asignalxextension-axttraroundtime), and axtturegaroundtime may be equal to 4 μs. For example, when a PPDU associated with a multi-band STA is scheduled to be transmitted before expiration of a timer from another STA, the wireless AP associated with the multi-band AP does not transmit a trigger frame with a CS required subfield set to 1 to the STA associated with the unified multi-band STA, wherein the timer has a value of 12 μs (asifstime+asignalxextension-arrturebasis time, wherein arrturebasis time is equal to 4 μs). In this case, the wireless AP and the wireless STA follow the CS required rules (e.g., 26.5.2ul MU operation) defined according to the IEEE 802.11ax specification.

According to some embodiments, the AP may allocate traffic to different links based on QoS policies of a Basic Service Set (BSS). For example, when a frame belonging to a Traffic Identifier (TID) 1 is allocated to link 1 and a frame belonging to TID 2 is allocated to link 2, the HE TB PPDU transmitted on the multiple links carries a frame belonging to the QoS policy. For example, if the wireless AP allocates a frame belonging to TID 1 to link 1, the HE TB PPDU transmitted through link 1 carries only the frame belonging to TID 1. When using MAC padding, the wireless STA may aggregate frames assigned to other links as determined by the wireless AP. The AP may indicate in the trigger frame whether the wireless STA may aggregate frames allocated to other links.

With respect to fig. 6, an exemplary limited multiple link operation 600 using triggered uplink access that results in reception errors due to interference leakage between wireless links is shown in accordance with an embodiment of the present invention. In fig. 6, wireless AP 605 transmits trigger frame 615 to wireless STA 610 to request an uplink response frame on 6GHz wireless link 620 and to request trigger frame 625 on 6GHz wireless link 630. The EHT TB PPDU 635 is transmitted by the wireless STA 610 in response to the trigger frame 615. The length of the EHT TB PPDUs (e.g., EHT TB PPDUs 635 and 640) is determined from the respective trigger frames transmitted over the links associated with the EHT TB PPDUs. In fig. 6, the difference between the end times of the plurality of EHT TB PPDUs is greater than SIFS- (10% x as lottime), resulting in interference leakage, and the wireless STA cannot decode the response frame (block ACK) 645.

With respect to fig. 7, an exemplary limited multi-link operation 700 for preventing interference leakage using triggered uplink access is depicted in accordance with an embodiment of the present invention. In fig. 7, wireless AP 705 transmits trigger frame 715 to wireless STA 710 to request an uplink response frame over 5GHz wireless link 720 and transmit trigger frame 725 over 6GHz wireless link 730. The TB PPDU 735 is transmitted by the wireless STA 710 in response to the trigger frame 715, and the TB PPDU 740 is transmitted by the wireless STA 710 in response to the trigger frame 725. The UL length subfield values in the trigger frames 715 and 725 are set such that the difference between the end times of the TB PPDUs 735 and 740 is less than or equal to SIFS- (10% ×aslottime). According to some embodiments, SIFS- (10% x aSlotTime) is the maximum limit for PPDU end time alignment, although more stringent synchronization requirements (e.g., SIFS- (10% x aSlotTime) -aCCATime or 8 μs) may be applied.

Fig. 8 is a flowchart 800 depicting an exemplary sequence of computer implemented steps for performing limited multi-link triggered uplink access to prevent IDC interference in accordance with an embodiment of the present invention.

In step 805, first and second trigger frames are received from a wireless Access Point (AP) of a wireless Station (STA) over first and second wireless links, respectively.

In step 810, a difference between an end time of a PPDU carrying a first trigger frame and an end time of a PPDU carrying a second trigger frame is calculated.

In step 815, when a difference between an end time of the PPDU carrying the first trigger frame and an end time of the PPDU carrying the second trigger frame is less than a predetermined margin, the first data frame and the second data frame are transmitted in the PPDU over the first wireless link and the second wireless link, respectively, in response to the first trigger frame and the second trigger frame. According to some embodiments, the predetermined margin is calculated as: SIFS- (10% ×aslottime). According to some embodiments, SIFS- (10% x aSlotTime) is the maximum limit for PPDU end time alignment, although more stringent synchronization requirements (e.g., SIFS- (10% x aSlotTime) -aCCATime or 8 μs) may be applied. According to some embodiments, the end time of the PPDU is adjusted, for example, using MAC padding, PHY padding, and/or PE.

Fig. 9 is a flow chart 900 depicting an exemplary sequence of computer implemented steps for performing constrained multi-link triggered uplink access to prevent wireless links from entering a busy state due to interference leakage, in accordance with an embodiment of the present invention.

In step 905, in a multi-link operation, a first trigger frame is transmitted in a PPDU from a wireless Access Point (AP) to a wireless Station (STA) over a first wireless link. The wireless AP and the wireless STA are MLDs that can communicate through a plurality of wireless links. The first trigger frame includes a CS required field having a value of 1, which indicates that channel sensing is performed before a wireless STA transmitting in response to the trigger frame transmits a PPDU.

In step 910, the wireless AP determines that the AP is scheduled to transmit a second trigger frame in the PPDU over a second wireless link. The second trigger frame is sent by the AP instance associated with the wireless AP to the STA instance associated with the wireless STA.

In step 915, the wireless AP (e.g., an AP affiliated with the wireless AP) transmits the second trigger frame when a difference between a start time of the PPDU transmitted by the wireless STA in response to the first trigger frame and an end time of the second trigger frame is greater than or equal to a predetermined margin. According to some embodiments, the predetermined margin is set according to an atcatime defined by the wireless AP. For example, aCCATime may be determined from aSIFSTime+aSignalExtension-aRxTxTurnaroundTime, where aRxTxTurnaroundTime is equal to 4 μs. For example, the predetermined margin may be 12 μs. According to some embodiments, the end time of the PPDU is adjusted, for example, using MAC padding, PHY padding, and/or PE.

Fig. 10 is a flow 1000 depicting an exemplary sequence of computer-implemented steps for performing constrained multi-link triggered uplink access to prevent interference leakage between a first wireless link and a second wireless link in accordance with an embodiment of the invention.

In step 1005, first and second trigger frames are received from a wireless Access Point (AP) of a wireless Station (STA) over first and second wireless links, respectively.

In step 1010, the difference between the end time of the PPDU carrying the first data frame and the end time of the PPDU carrying the second data frame is calculated.

In step 1015, the UL length field of the first and/or second PPDUs is adjusted such that the difference between the end times of the multiple responding PPDUs is less than or equal to SIFS- (10% ×aslottime).

In step 1020, a first data frame and a second data frame are transmitted in the PDDU in response to the first trigger frame and the second trigger frame on the first wireless link and the second wireless link, respectively. The end time of the data frame is substantially aligned within a predetermined margin to advantageously prevent channel leakage interference caused by the receipt of subsequent response frames (e.g., ACKs or block ACKs) at the wireless STA. According to some embodiments, the end time of the PPDU is adjusted, for example, using MAC padding, PHY padding, and/or PE.

In step 1025, a response frame is received in response to the wireless AP receiving the first data frame, and interference leakage is substantially prevented.

Embodiments of the present invention relate to an electronic system that performs multiple link operations in a wireless network. The multi-link operation may include a constrained multi-link operation that is constrained to prevent or mitigate IDC interference, for example, by aligning the start/end times of received/transmitted frames within a predetermined margin, thereby substantially preventing simultaneous transmission and reception. For example, frame timing (frame timing) may be aligned using MAC padding, PHY padding, and/or Packet Expansion (PE). The following discussion describes one such exemplary electronic or computer system that may be used as a platform to implement embodiments of the present invention. For example, exemplary computer system 1112 can be a wireless access point or a wireless station.

In the example of fig. 11, an exemplary computer system or wireless device includes a central processing unit (e.g., processor or CPU) 1101 for running software applications and an optional operating system. The read only memory 1102 and the random access memory 1103 store application programs and data for use by the CPU 1101. The data storage device 1104 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. Optional user input devices 1106 and 1107 include devices (e.g., a mouse, joystick, camera, touch screen, and/or microphone) that communicate input from one or more users to computer system 1112.

Communication or network interface 1108 includes a number of transceivers and allows computer system 1112 to communicate with other computer systems, networks, or devices via an electronic communication network including wired and/or wireless communication, including a local area network or the internet (e.g., 802.11 wireless standards). For example, network interface 1108 may perform multi-link operations (e.g., multi-link packet scheduling and channel access) using multiple wireless links to improve network throughput. According to an embodiment of the invention, the communication or network interface 1108 may operate multiple transceivers simultaneously. Communication or network interface 1108 and may include a multi-band (e.g., dual-band) interface that may operate in multiple frequency bands (e.g., 2.4GHz, 5GHz, and/or 6 GHz) simultaneously.

The optional display device 1109 may be any device capable of displaying visual information in response to a signal from computer system 1112 and may include, for example, a flat-panel touch-sensitive display, and may be remotely located. Components of computer system 1112, including CPU 1101, memory 1102/1103, data store 1104, user input device 1106, and graphics subsystem 1105 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. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Generally, the functionality of the program modules may be combined or distributed as desired in various embodiments.

Thus, embodiments of the present invention have been described. While the invention has been described in particular embodiments, it should be appreciated that the invention should not be construed as limited by such embodiments, but rather construed according to the below claims.

Claims (20)

1. A data transmission method for data based on multiple link triggers in a wireless network, the data transmission method comprising:

transmitting a first trigger frame from a first affiliated wireless access point of the multi-band wireless access point to the wireless station over the first wireless link, wherein the first trigger frame includes a carrier sense required field having a value of 1;

determining that a second affiliated wireless access point of the multi-band wireless access point is scheduled to transmit a second trigger frame to the wireless station over a second wireless link; and

the wireless station transmits a second trigger frame from the second subordinate wireless access point to the wireless station over the second wireless link when a difference between a start time of an entity layer consistency procedure protocol data unit transmitted by the wireless station in response to the first trigger frame and an end time of the second trigger frame is equal to or greater than a predetermined margin.

2. The data transmission method according to claim 1, wherein the predetermined margin is determined based on calculation of asifstime+asignalxextension-arxtturnarondtime.

3. The data transmission method according to claim 1, wherein the predetermined margin is 12 μs.

4. The data transmission method of claim 1, wherein the predetermined margin is determined according to a requirement of the wireless access point.

5. The data transmission method of claim 1, wherein the first wireless link comprises a 6GHz wireless link and the second wireless link comprises a 5GHz wireless link.

6. A data transmission method for data based on multiple link triggers in a wireless network, the data transmission method comprising:

receiving a first trigger frame and a second trigger frame from a wireless access point at a wireless station over a first wireless link and a second wireless link, respectively;

calculating a difference between an end time of a first entity layer coherence protocol data unit carrying the first trigger frame and an end time of a second entity layer coherence protocol data unit carrying the second trigger frame; and

when a difference between an end time of the first physical layer coherence protocol data unit of the first trigger frame and an end time of the second physical layer coherence protocol data unit carrying the second trigger frame is greater than a predetermined value, transmitting a first data frame and a second data frame respectively in response to the first trigger frame and the second trigger frame over the first wireless link and the second wireless link.

7. The data transmission method of claim 6, wherein the predetermined value is determined according to a short interframe space (SIFS) - (10% x aSlotTime), and wherein aSlotTime is determined according to a specification of the wireless network.

8. The data transmission method according to claim 6, wherein the predetermined value is selected from the group consisting of: 4 μs,8 μs and 16 μs.

9. The data transmission method of claim 6, wherein the first entity layer coherence protocol data unit and the second entity layer coherence protocol data unit are formatted using one of: non HT, HT, VHT, HE and EHT formats.

10. The data transmission method of claim 6, further comprising adjusting the end time of the first entity layer coherence protocol data unit by adjusting a MAC padding of the first entity layer coherence protocol data unit.

11. The data transmission method of claim 6, further comprising adjusting the end time of the first entity layer coherence protocol data unit by adjusting PHY padding of the first entity layer coherence protocol data unit.

12. The data transmission method of claim 6, further comprising adjusting the end time of the first entity layer coherence protocol data unit by adjusting a PE frame of the first entity layer coherence protocol data unit.

13. The data transmission method of claim 6, wherein the first wireless link comprises a 6GHz wireless link and the second wireless link comprises a 5GHz wireless link.

14. The data transmission method of claim 6, wherein adjusting the end time of the first physical layer coherence protocol data unit mitigates in-device coexistence interference.

15. A data transmission method for data based on multiple link triggers in a wireless network, the data transmission method comprising:

receiving a first trigger frame and a second trigger frame from a wireless access point at a wireless station over a first wireless link and a second wireless link, respectively;

transmitting a first data frame and a second data frame to the wireless access point through the first wireless link and the second wireless link in response to the first trigger frame and the second trigger frame, respectively; and

receiving an acknowledgement, wherein the transmitting comprises:

calculating a difference between an end time of a first entity layer coherence protocol data unit carried to a first data frame and an end time of a second entity layer coherence protocol data unit carried to the second data frame; and

and setting an UL length field of the first physical layer coherence protocol data unit according to a difference between the end time of the first physical layer coherence protocol data unit and the end time of the second physical layer coherence protocol data unit to prevent interference leakage between the first radio link and the second radio link when receiving the acknowledgement.

16. The data transmission method of claim 15, wherein the UL length field of the first physical layer coherence protocol data unit is set such that a difference between the end time of the first physical layer coherence protocol data unit and the end time of the second physical layer coherence protocol data unit is greater than SIFS- (10%. Times.aslottime), and wherein aSlotTime is determined according to a specification of the wireless access point.

17. The data transmission method of claim 15 wherein setting the UL length field of the first physical layer protocol data unit prevents transmission of the second data frame during receipt of the acknowledgement.

18. The data transmission method of claim 15, wherein the first wireless link comprises a 6GHz wireless link and the second wireless link comprises a 5GHz wireless link.

19. The data transmission method of claim 15, further comprising: PHY padding is performed on the acknowledgement.

20. The data transmission method of claim 15, further comprising: MAC population is performed on the acknowledgement.