PREEMPTION OPERATION
FIELD
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Various example embodiments relate to the field of telecommunication and in particular, to a method, device, apparatus and computer readable storage medium of communication for preemption operation.
BACKGROUND
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Latency improvement is one of main requirements in ultra-high reliability (UHR) . Several new features are developed to support low latency traffic. These features include a multi-link operation (MLO) , a restricted target wake time (R-TWT) and an MLO stream classification service (MSCS) based quality of service (QoS) signaling mechanism.
SUMMARY
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In general, example embodiments of the present disclosure provide a solution of communication for preemption operation.
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In a first aspect, there is provided a device. The device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the device at least to: perform a first transmission with a second device within a transmission opportunity in a first link among multiple links established between the device and the second device; receive, from the second device and via one of the first link and a second link among the multiple links, an indication that the first link is preempted for a second transmission between the second device and a third device within the transmission opportunity; and stop, based at least on the indication, the first transmission in the first link.
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In a second aspect, there is provided a device. The device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the device at least to: perform a first transmission with a first device within a transmission opportunity in a first link among multiple links established between the device and the first device; determine that a second transmission between the device and a third device is to be performed within the transmission opportunity; and transmit, to the first device and via one of the first link and a second link among the multiple links, an
indication that the first link is preempted for the second transmission.
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In a third aspect, there is provided a method. The method comprises: performing, at a first device, a first transmission with a second device within a transmission opportunity in a first link among multiple links established between the first device and the second device; receiving, from the second device and via one of the first link and a second link among the multiple links, an indication that the first link is preempted for a second transmission between the second device and a third device within the transmission opportunity; and stopping, based at least on the indication, the first transmission in the first link.
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In a fourth aspect, there is provided a method. The method comprises: performing, at a second device, a first transmission with a first device within a transmission opportunity in a first link among multiple links established between the second device and the first device; determining that a second transmission between the second device and a third device is to be performed within the transmission opportunity; and transmitting, to the first device and via one of the first link and a second link among the multiple links, an indication that the first link is preempted for the second transmission.
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In a fifth aspect, there is provided an apparatus. The apparatus comprises: means for performing a first transmission with a second device within a transmission opportunity in a first link among multiple links established between the apparatus and the second device; means for receiving, from the second device and via one of the first link and a second link among the multiple links, an indication that the first link is preempted for a second transmission between the second device and a third device within the transmission opportunity; and means for stopping, based at least on the indication, the first transmission in the first link.
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In a sixth aspect, there is provided an apparatus. The apparatus comprises: means for performing a first transmission with a first device within a transmission opportunity in a first link among multiple links established between the apparatus and the first device; means for determining that a second transmission between the second device and a third device is to be performed within the transmission opportunity; and means for transmitting, to the first device and via one of the first link and a second link among the multiple links, an indication that the first link is preempted for the second transmission.
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In a seventh aspect, there is provided a non-transitory computer readable medium
comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the method according to the third or fourth aspect.
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In an eighth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus to perform at least the method according to the third or fourth aspect.
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It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
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Some example embodiments will now be described with reference to the accompanying drawings, where:
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Fig. 1 illustrates an example communication network in which embodiments of the present disclosure may be implemented;
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Fig. 2 illustrates a diagram illustrating an example MLO in which embodiments of the present disclosure may be implemented;
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Fig. 3 illustrates a diagram illustrating an example R-TWT based transmission in which embodiments of the present disclosure may be implemented;
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Fig. 4 illustrates a diagram illustrating an example preemption operation based on a block acknowledgement (BA) frame according to a related solution;
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Fig. 5 illustrates a diagram illustrating an example process of communication according to some embodiments of the present disclosure;
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Fig. 6 illustrates a flowchart of an example method implemented at a device as a transmission opportunity (TXOP) holder according to some embodiments of the present disclosure;
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Fig. 7 illustrates a flowchart of an example method implemented at a device as a non-TXOP holder according to some embodiments of the present disclosure;
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Fig. 8 illustrates a simplified block diagram of a device that is suitable for implementing embodiments of the present disclosure; and
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Fig. 9 illustrates a block diagram of an example computer readable medium in accordance with some embodiments of the present disclosure.
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Throughout the drawings, the same or similar reference numerals represent the same or similar element.
DETAILED DESCRIPTION
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Principles of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.
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In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.
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References in the present disclosure to “one embodiment, ” “an embodiment, ” “an example embodiment, ” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.
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It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms in any way other than only to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.
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The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used
herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. As used herein, “at least one of the following: <a list of two or more elements>” and “at least one of <a list of two or more elements>” and similar wording, where the list of two or more elements are joined by “and” or “or” , mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.
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As used in this application, the term “circuitry” may refer to one or more or all of the following:
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(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and
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(b) combinations of hardware circuits and software, such as (as applicable) :
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(i) a combination of analog and/or digital hardware circuit (s) with software/firmware and
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(ii) any portions of hardware processor (s) with software (including digital signal processor (s) ) , software, and memory (ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and
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(c) hardware circuit (s) and or processor (s) , such as a microprocessor (s) or a portion of a microprocessor (s) , that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.
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This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.
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As used herein, the term “communication network” refers to a network following any suitable communication standards, such as Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , Narrow Band Internet of Things (NB-IoT) , and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) , the future sixth generation (6G) communication protocols, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like and/or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.
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As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The communication network may be a core network (CN) . The network device in CN (also referred to as core network device herein) may refer to a policy control function (PCF) , an access management function (AMF) , a session management function (SMF) , a user plane function (UPF) , unified data management (UDM) , unified data repository (UDR) , an authentication server function (AUSF) , a ProSe key management function (PKMF) , a direct discovery name management function (DDNMF) , a network exposure function (NEF) , etc..
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The communication network may be a radio access network (RAN) . The network device in RAN may refer to a base station (BS) or an access point (AP) , for example, a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a NR next generation NodeB (also referred to as a gNB) , a Remote Radio Unit (RRU) , a radio header (RH) , a remote radio head (RRH) , a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology. An radio access network (RAN) split architecture comprises a gNB-CU (centralized unit, hosting radio resource control (RRC) , service data adaptation protocol (SDAP) and packet data convergence protocol (PDCP) layers) controlling a plurality of gNB-DUs (distributed unit, hosting radio
link control (RLC) , medium access control (MAC) and physical (PHY) layers) .
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The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE) , a Subscriber Station (SS) , a Portable Subscriber Station, a Mobile Station (MS) , or an Access Terminal (AT) . The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA) , portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , USB dongles, smart devices, wireless customer-premises equipment (CPE) , an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD) , a vehicle, a drone, a medical device and applications (e.g., remote surgery) , an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts) , a consumer electronics device, a device operating on commercial and/or industrial wireless networks, or the like. In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” , “UE” and “STA” (station) may be used interchangeably.
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As used herein, the term “AP device” may refer to a device via which to access any wired or wireless network. For example, the wired or wireless network may be a broadband network, the Internet, a local area network, a metropolitan area network, a mobile communication network, or the like. For convenience, AP devices are also referred to as AP stations or APs herein. The AP device may support, for example, the Wi-Fi protocol or any other known or future-developed similar protocols. For example, the AP device may be a wireless router, a terminal device with a router function, a network device with a router function, and so on. The term “non-AP device” may refer to a device for accessing any wired or wireless network via an AP device. Non-AP devices may support, for example, the Wi-Fi protocol or any other known or future developed similar protocols. For example, a non-AP device may be any of a terminal device, a network device, and so on. For convenience, non-AP devices are also referred to as non-AP stations or non-APs herein. It should be understood that the term “station” may refer to an AP station or a non-AP station.
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Although functionalities described herein can be performed, in various example embodiments, in a fixed and/or a wireless network node, in other example embodiments, functionalities may be implemented in a user equipment apparatus (such as a cell phone or tablet computer or laptop computer or desktop computer or mobile IoT device or fixed IoT device) . This user equipment apparatus can, for example, be furnished with corresponding capabilities as described in connection with the fixed and/or the wireless network node (s) , as appropriate. The user equipment apparatus may be the user equipment and/or a control device, such as a chipset or processor, configured to control the user equipment when installed therein. Examples of such functionalities include the bootstrapping server function and/or the home subscriber server, which may be implemented in the user equipment apparatus by providing the user equipment apparatus with software configured to cause the user equipment apparatus to perform from the point of view of these functions/nodes.
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Wi-Fi systems are deployed on unauthorized or unlicensed spectrum, where multiple stations compete to use channel resources. A station with successful channel competition may reserve the channel for a period of time before data transmission. The period of time is called as a transmission opportunity (TXOP) . Only this station may actively transmit data within the TXOP, while other stations may only receive data or transmit corresponding response frames. This station is called as a TXOP holder, and any of the other stations is called as a non-TXOP holder.
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Embodiments of the present disclosure provide a solution of communication for preemption within a TXOP. In the solution, a first device as a TXOP holder is performing a first transmission with a second device as a non-TXOP holder within a TXOP in a first link among multiple links established between the first device and the second device. Upon determination that a second transmission between the second device and a third device is to be performed within the TXOP, the second device transmits, to the first device and via one of the first link and a second link among the multiple links, an indication that the first link is preempted for the second transmission within the TXOP. Based at least on the indication, the first device stops the first transmission in the first link. In this way, preemption of an on-going transmission within a TXOP may be achieved. Latency reduction of a low-latency data transmission in UHR may be facilitated.
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In the context of the present disclosure, the term “low-latency data” may be interchangeably used with “high priority data” or “high priority and low latency data
(HPLLD) ” .
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Principles and implementations of the present disclosure will be described in detail below with reference to the figures.
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Fig. 1 illustrates a schematic diagram of an example communication network 100 in which embodiments of the present disclosure can be implemented. As shown in Fig. 1, the communication network 100 may include devices 110 and 120 as non-AP devices and a device 130 as an AP device for a WLAN (e.g., a Wi-Fi network) . Each of the devices 110 and 120 may support setting up one or multiple links with an AP device. The device 130 may support setting up one or multiple links with a non-AP device.
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In some embodiments, a non-AP device (e.g., the device 110 or 120) may communicate with a CN (not shown) via an AP device (e.g., the device 130) in a WLAN (e.g., a Wi-Fi network) .
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In this example, the devices 110 and 120 are illustrated as mobile phones, and the device 130 is illustrated as a router. It should be noted that any of the devices 110, 120 and 130 may be any other suitable types of terminal devices or network devices, such as mobile phones, sensors and so on. Further, it is to be understood that the number of devices is only for the purpose of illustration without suggesting any limitations. The communication network 100 may include any suitable number or type of devices adapted for implementing embodiments of the present disclosure.
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Communications in the communication network 100 may be implemented according to any proper communication protocol (s) , comprising, but not limited to, cellular communication protocols of the first generation (1G) , the second generation (2G) , the third generation (3G) , the fourth generation (4G) , the fifth generation (5G) , the future sixth generation (6G) , wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and/or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA) , Frequency Division Multiple Access (FDMA) , Time Division Multiple Access (TDMA) , Frequency Division Duplex (FDD) , Time Division Duplex (TDD) , Multiple-Input Multiple-Output (MIMO) , Orthogonal Frequency Division Multiple (OFDM) , Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and/or any other technologies currently known or to be developed in the future.
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In the context of the present disclosure, if a non-AP STA supports MLO, the non-AP STA may also be called as a non-AP MLD. If an AP supports MLO, the AP may also be called as an AP MLD. In this case, the term “non-AP STA” may be interchangeably used with “non-AP MLD” or “non-AP device” , and the term “AP” may be interchangeably used with “AP MLD” or “AP device” .
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In some scenarios, a non-AP MLD (e.g., the device 110 or 120) and an AP MLD (e.g., the device 130) may communicate with each other via multiple links. Fig. 2 illustrates a diagram 200 illustrating an example MLO in which embodiments of the present disclosure may be implemented. As shown in Fig. 2, before multi-link setup, the AP MLD and the non-AP MLD may only communicate on a single link, e.g., via 2.4GHz wireless medium (WM) . For example, the non-AP MLD may transmit an association request frame to the AP MLD and receive an association response frame from the AP MLD via 2.4GHz link. After successful multi-link setup, three links on 2.4GHz, 5GHz and 6GHz may be established for simultaneous communication between the AP MLD and the non-AP MLD.
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By doing so, data throughput may be increased by mapping multiple traffic streams to multiple links instead of one link. To support requirements of a low latency application, traffic of the low latency application may be mapped to a link with a lower latency to ensure that data is transmitted without a need for retransmissions. For example, the link may be any channel in the 6GHz band. For UHR, it is being discussed whether to support 60GHz bands as potential links under MLO. When adopted, UHR devices may take advantage of several GHz of frequency resources in these bands to support low latency applications.
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In some scenarios, an R-TWT mechanism may be supported by the device 110, 120 or 130. The R-TWT mechanism is a variant of a target wake time (TWT) mechanism. In the TWT mechanism, pre-defined service periods (SP) may be assigned to non-AP devices for transmitting and receiving packets to optimize power consumption. During these SPs, non-AP devices cannot switch to a sleep mode (e.g., a doze state) . However, if a channel is busy during a non-AP device’s allocated TWT SP due to another non-AP device that is not in a TWT group transmitting before the TWT SP starting time, the non-AP device in the TWT group may experience a service delay issue.
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The R-TWT (restricted target wake time) mechanism addresses this issue by
requiring non-AP devices, which are not members of the R-TWT, to end their current transmissions before a start of the R-TWT SP. Fig. 3 illustrates a diagram 300 illustrating an example R-TWT based transmission in which embodiments of the present disclosure may be implemented. As shown in Fig. 3, in an R-TWT SP 310, AP may send a trigger frame to a non-AP device (e.g., STA 2) with high priority data, and the STA2 may join the R-TWT SP 310 to transmit the high priority data. Another non-AP device (e.g., STA 1) with low priority data, which is not a member of R-TWT SP, ensures that transmission of the low priority data completes before the R-TWT SP starts and continues transmitting any remaining frames of the low priority data after the R-TWT SP.
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It can be known that the R-TWT mechanism may provide increased determinism specially for periodic traffic. However, it may be ineffective in providing protection for non-periodic low latency traffic. Non-periodic low latency traffic may include emergency stop packets for wirelessly controlled factory robots and sensor packets for virtual reality (VR) and game controllers. When a non-AP device is already transmitting a low priority frame, there is no way for another non-AP device to transmit a high priority frame until the on-going transmission is completed.
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To schedule a low latency (with high priority) traffic transmission at any time, solutions of preempting the on-going transmission (with low priority) and reusing a TXOP have been proposed. Fig. 4 illustrates a diagram 400 illustrating an example preemption operation based on a BA frame according to a related solution. As shown in Fig. 4, STA1 as a TXOP holder may transmit a request to send (RTS) frame 410 to AP and the AP may transmit a clear to send (CTS) frame 420 to the STA1 as a response. Then STA1 may transmit non-low latency data (i.e., low priority data) 430 to the AP.
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With reference to Fig. 4, low latency data (i.e., high priority data) for STA2 may arrive at the AP STA1 at a timing A while the STA1 is transmitting the non-low latency data 430 to the AP. To transmit the low latency data to STA2, the AP may need to preempt the TXOP initiated by the STA1. As shown in Fig. 4, the AP may terminate the transmission of the non-low latency data by transmitting a BA frame 440 to the STA1. Then, the AP may transmit the low latency data 450 to the STA2 within the STA1’s TXOP. The STA2 may transmit a BA frame 460 to the AP upon reception of the low latency data. The STA1 may continue transmission of the non-low latency data 470 to the AP in remaining time of the STA1’s TXOP.
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However, the AP may need to transmit the BA frame after receiving an aggregated medium access control (MAC) protocol data unit (A-MPDU) frame from the STA 1, and then transmit the low latency data to the STA 2 following the BA frame transmission immediately. A-MPDU is a mechanism that allows multiple MAC protocol data unit (MPDU) frames to be aggregated into a single presentation protocol data unit (PPDU) for transmission. The maximum duration of an A-MPDU frame depends on several factors, like modulation and coding scheme (MCS) , number of spatial streams (NSS) , channel condition, etc.. Especially, the maximum duration at 20 MHz channel width is 4095.375 μs, while the maximum duration at 160 MHz channel width is up to 32767.875 μs. Consequently, if the AP delays low-latency data transmission before finishing a long A-MPDU transmission, a significant waiting delay will arise for low-latency traffic.
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It is assumed that multiple links are established for communication between a TXOP holder (e.g., AP/STA) and a non-TXOP holder (e.g., STA/AP) . The TXOP holder is already transmitting a low priority frame in one of the multiple links, and the non-TXOP holder may desire to transmit a high priority frame to a receiver (e.g., the TXOP holder or another device) within the TXOP in the one of the multiple links as soon as possible. An issue is how the non-TXOP holder interrupts the on-going frame transmission for the high priority frame transmission within the TXOP or/and how the TXOP holder continues the low priority frame transmission within remaining time of the TXOP in the one of the multiple links after the high priority frame transmission is finished.
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In view of this, embodiments of the present disclosure provide a solution of communication for preemption operation so as to overcome the above and other potential issues. In the solution, a preemption solution within a TXOP is proposed for low-latency data transmission in UHR. This solution may benefit latency reduction of low-latency data transmission by preempting an on-going transmission within the TXOP. Its details will be described below in connection with Fig. 5.
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Fig. 5 illustrates a diagram illustrating an example process 500 of communication according to some embodiments of the present disclosure. For the purpose of discussion, the process 500 will be described with reference to Fig. 1. The process 500 may involve the devices 110, 120 and 130 as illustrated in Fig. 1. It would be appreciated that although the process 500 has been described in the communication network 100 of Fig. 1, this process may be likewise applied to other communication scenarios.
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In this example, it is assumed that the device 110 is a TXOP holder and the device 120 is a non-TXOP holder, and that multiple links are established between the device 110 and the device 120. It is to be understood that a TXOP holder may be a non-AP device, and a non-TXOP holder may be an AP device. Alternatively, a TXOP holder may be an AP device, and a non-TXOP holder may be a non-AP device.
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As shown in Fig. 5, the device 110 as a TXOP holder may perform 510 a transmission (for convenience, also referred to as a first transmission herein) with the device 120 as a non-TXOP holder in one of the multiple links (for convenience, also referred to as a first link herein) . For example, after the device 110 successfully initiates a TXOP in the first link, the device 110 may transmit a frame to the device 120 using the TXOP. Accordingly, the device 120 may transmit a response to the device 110. In this way, the first transmission is performed between the device 110 and the device 120.
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With reference to Fig. 5, the device 120 as the non-TXOP holder may determine 520 that another transmission (for convenience, also referred to as a second transmission herein) of the device 120 is to be performed within the TXOP. In some embodiments, the second transmission may be performed between the device 120 and a device (e.g., the device 130) different from the device 110. In some embodiments, the second transmission may be performed between the device 120 and the device 110. For illustration, in the example of Fig. 5, the second transmission 550 is shown as being performed between the device 120 and the device 130.
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Continuing to refer to Fig. 5, the device 120 may buffer 521 data associated with the second transmission. That is, the device 120 is required to transmit the data. In some embodiments, based on the buffering of the data, the device 120 may determine that the second transmission is to be performed. In some embodiments, the device 120 may compare a priority of the second transmission with a priority of the first transmission. In some embodiments, the device 120 may determine the priority of the first transmission based on a MAC header of the first transmission. If the priority of the second transmission is above (i.e., higher than or equal to) the priority of the first transmission, the device 120 may determine that the second transmission is to be performed.
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Continuing to refer to Fig. 5, the device 120 may determine 522 that the second transmission from the device 130 is to be triggered. That is, the device 120 is required to receive data from the device 130. For example, if the device 120 as the non-TXOP holder
needs to receive data from the device 130 within the TXOP initiated by the device 110 as the TXOP holder, the device 120 may determine transmitting a trigger frame to the device 130 so as to receive the data from the device 130.
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In some embodiments, the device 120 may determine whether the second transmission is to be triggered based on a traffic priority associated with the second transmission. In some embodiments, the device 120 may determine that the second transmission is to be triggered based on a scheduling request associated with the second transmission. In some embodiments, the device 120 may determine that the second transmission is to be triggered based on a traffic identifier (TID) to link mapping associated with the second transmission. It is to be understood that any combination of the above information may also be feasible for determination of whether to trigger the second transmission.
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Upon determination that the second transmission is to be performed, the device 120 may decide to preempt the first link to perform the second transmission within the TXOP of the device 110. With reference to Fig. 5, the device 120 may transmit 530, to the device 110 via one of the first link and another link (for convenience, also referred to as a second link herein) , an indication that the first link is preempted for the second transmission.
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As shown in Fig. 5, in some embodiments, the device 120 may transmit 531 the indication via the second link. In some embodiments, the device 120 may select, as the second link, one of the multiple links that is different from the first link. The second link shall have been activated for MLO between the devices 110 and 120. In some embodiments, the device 120 may select one of the multiple links that has a low channel busy ratio. In some embodiments, the device 120 may cause one or more links to grab a channel and select, as the second link, a link that first passes listen before talk (LBT) . It is to be understood that the second link may be selected based on any other suitable rules.
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In some embodiments, if a further TXOP is obtained for the second link for transmission of the indication during the first transmission, the device 120 may transmit, in the second link, a frame (for convenience, also referred to as a first frame herein) comprising the indication. In some embodiments, if the further TXOP is obtained for the second link for transmission of the indication after the first transmission is finished, the device 120 may transmit, in the second link, the first frame comprising the indication.
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In some embodiments, the first frame may comprise a control frame. In some embodiments, the first frame may comprise a management frame, e.g., an action frame. In some embodiments, the first frame may comprise a data frame. For example, a control field capsulated in a management frame or a data frame may be used to carry the indication. It is to be understood that the first frame may adopt any other suitable forms.
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As shown in Fig. 5, in some embodiments, the device 120 may transmit 532 the indication via the first link. In some embodiments, if no TXOP is obtained for the second link for transmission of the indication during the first transmission, the device 120 may transmit, in the first link, a frame (for convenience, also referred to as a second frame herein) comprising the indication after the first transmission is finished.
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In some embodiments, the second frame may comprise a frame (e.g., a BA frame) for block acknowledgement of the first transmission. In some embodiments, a field may be designed in the BA frame to carry the indication. It is to be understood that the second frame may adopt any other suitable forms.
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In some embodiments, the indication may include information of the first link. In other words, the indication may comprise information of a link to be preempted for the second transmission. In some embodiments, if the information of the link to be preempted is not included in the indication, a link which transmits the indication may be applied for the second transmission.
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In some embodiments, the indication may include information of an occasion of the second transmission. The information of the occasion is to indicate where the second transmission is performed in the time domain. In some embodiments, the indication may include information of a duration of the second transmission. The information of the duration is to indicate how long the second transmission is performed in the time domain. In some embodiments, the indication may include information of the priority of the second transmission.
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In some embodiments, the indication may include information of whether the second transmission is associated with the device 110. In other words, this information is used to indicate whether the device 110 is a participant or receiver of the second transmission. In some embodiments, if the indication may include information that the second transmission is unassociated with the device 110, the device 110 may enter a sleep mode (e.g., a doze state) during the duration of the second transmission. In this way,
reduced power consumption at a TXOP holder may be achieved. In some embodiments, if the indication may include information that the second transmission is associated with the device 110, the device 110 may monitor data from the device 120. In some embodiments where the device 110 is configured with a TWT SP or R-TWT SP, the device 110 may monitor the data from the device 120 based on the TWT SP or R-TWP SP. In some embodiments where the device 110 is not configured with a TWT SP or R-TWT SP, the device 110 may always monitor the data from the device 120.
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It is to be understood that the indication may include any combination of the above information or any other suitable information.
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In some embodiments, the preemption may be performed during a TWT SP configured for the device 130. For example, the device 120 as the non-TXOP holder may preempt the TXOP during an individual and/or a broadcasted TWT SP including R-TWT SP if configured for the device 130.
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In some embodiments, the preemption may be performed at any time of the TXOP. For example, the device 120 as the non-TXOP holder may preempt the TXOP at any time of the TXOP if the device 130 (e.g., as a receiver) is not configured in a TXOP power save mode, i.e., the receiver as a non-TXOP holder will not enter a sleep mode (e.g., a doze state) and will always monitoring on-going frame transmission even if a TXOP is detected. It is to be understood that a very high throughput (VHT) /high efficiency (HE) /extremely high throughput (EHT) STA that is in a TXOP power save mode and has entered a sleep mode (e.g., a doze state) may continue to operate its network allocation vector (NAV) during the doze state and may transition into an awake state on expiration of the NAV. The STA may contend for access to the medium immediately on the expiration of the NAV.
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Continuing to refer to Fig. 5, upon reception of the indication, the device 110 may stop 540 the first transmission that is being performed in the first link. In some embodiments, the device 110 may compare the priority of the second transmission and the priority of the first transmission. If the priority of the second transmission is above (i.e., higher than or equal to) the priority of the first transmission, the device 110 may stop the first transmission. In this way, latency reduction of high priority and low latency data transmission may be ensured.
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Continuing to refer to Fig. 5, after preempting the TXOP in the first link, the device 120 may perform 550 the second transmission in the first link.
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In some embodiments where data associated with the second transmission is buffered at the device 120, the device 120 may transmit 551 the data to the device 130. In some embodiments, the device 130 may monitor a data transmission in the first link within the TWT SP or R-TWT SP if configured for the device 130. In some embodiments, the device 130 may monitor the data transmission in an active state if a TXOP power saving mode is configured. Upon reception of the data, the device 130 may transmit 552, to the device 120, a frame (e.g., a BA frame) for block acknowledgement of the data transmission. In this way, the second transmission may be performed.
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In some embodiments where the device 120 determines that the second transmission from the device 130 is to be triggered, the device 120 may transmit 553, to the device 130, a frame (e.g., a trigger frame) triggering the second transmission from the device 130. Based on the trigger frame, the device 130 may transmit 554, to the device 120, data buffered at the device 130 for the device 120. Upon reception of the data, the device 120 may transmit 555, to the device 130, a frame (e.g., a BA frame) for block acknowledgement of the second transmission. In this way, the second transmission may also be performed.
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Continuing to refer to Fig. 5, upon determination that the second transmission is finished, the devices 110 and 120 may continue 560 performing the first transmission within remaining time of the TXOP in the first link. In some embodiments, the device 110 may determine whether the second transmission is finished based on the information of the duration or occasion of the second transmission included in the received indication.
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With the process 500, preemption of an on-going transmission within a TXOP may be achieved. Latency reduction of a low-latency data transmission in UHR may be facilitated.
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It is to be noted that the above process 500 is merely an example, and may have additional or less operations. It is also to be noted that operations of the above process 500 may be carried out separately or in any suitable combination.
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Corresponding to the above process, example embodiments of the present disclosure also provide methods of communication implemented at a TXOP holder and a non-TXOP holder. For convenience, in the context of the present disclosure, a TXOP holder may also be referred to as a first device and a non-TXOP holder may also be referred to as a second device. A preemption operation is for transmission between the non-TXOP
holder and a further device, and the further device may also be referred to as a third device. In some embodiments, the third device may be the first device. In some embodiments, the third device may be a device different from the first device.
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Fig. 6 illustrates a flowchart of an example method 600 implemented at a device (i.e., the first device) as a TXOP holder according to some embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described with reference to Fig. 1. It is assumed that the device 110 is the first device (i.e., a TXOP holder) , the device 120 is the second device (i.e., a non-TXOP holder) , and the device 130 is the third device.
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At block 610, the device 110 performs a first transmission with the device 120 within a transmission opportunity in a first link among multiple links established between the device 110 and the device 120.
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At block 620, the device 110 receives, from the device 120 and via one of the first link and a second link among the multiple links, an indication that the first link is preempted for a second transmission between the device 120 and the device 130 within the transmission opportunity.
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In some embodiments, the device 110 may receive a first frame comprising the indication via the second link during the first transmission. In some embodiments, the device 110 may receive the first frame comprising the indication via the second link after the first transmission is finished. In some embodiments, the first frame may comprise at least one of a control frame, a management frame or a data frame. In this way, a preemption operation may be indicated to a TXOP holder in time by another available link. Thereby, preemption within a TXOP may be achieved.
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In some embodiments, the device 110 may receive a second frame comprising the indication via the first link after the first transmission is finished. In some embodiments, the second frame may comprise a frame for block acknowledgement of the first transmission. In this way, even if the second link is unavailable, a preemption operation may be indicated to a TXOP holder within the TXOP through the frame for block acknowledgement of the first transmission in the first link.
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In some embodiments, the indication may comprise at least one of the following: information of the first link; information of an occasion of the second transmission; information of a duration of the second transmission; information of a priority of the second
transmission; or information of whether the second transmission is associated with the device.
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At block 630, the device 110 stops, based at least on the indication, the first transmission in the first link. In some embodiments, if a priority of the second transmission is above a priority of the first transmission, the device 110 may stop the first transmission. In some embodiments, the device 110 may stop the first transmission upon reception of the indication. In this case, the device 110 may stop the first transmission without comparison of the priorities of the first and second transmissions.
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In some embodiments, if the second transmission is unassociated with the device 110, the device 110 may enter a sleep mode during the duration of the second transmission.
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In some embodiments, the device 110 may determine that the second transmission is finished based on the information of the duration of the second transmission or the information of the occasion of the second transmission, and continue performing the first transmission within remaining time of the transmission opportunity in the first link.
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With the method 600, preemption of an on-going transmission within a TXOP may be achieved. Latency reduction of a low-latency data transmission in UHR may be facilitated.
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Fig. 7 illustrates a flowchart of an example method 700 implemented at a non-TXOP holder according to some embodiments of the present disclosure. For the purpose of discussion, the method 700 will be described with reference to Fig. 1. It is assumed that the device 110 is the first device (i.e., a TXOP holder) , the device 120 is the second device (i.e., a non-TXOP holder) , and the device 130 is the third device.
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At block 710, the device 120 performs a first transmission with the device 110 within a transmission opportunity in a first link among multiple links established between the device 110 and the device 120.
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At block 720, the device 120 determines that a second transmission between the device 120 and the device 130 is to be performed within the transmission opportunity.
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In some embodiments, the device 120 may determine that data associated with the second transmission is buffered. If a priority of the second transmission is above a priority of the first transmission, the device 120 may determine that the second transmission is to be performed.
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In some embodiments, the device 120 may determine that the second transmission from the device 130 is to be triggered. In this case, the device 120 may determine that the second transmission is to be performed within the transmission opportunity. In some embodiments, the device 120 may determine that the second transmission from the device 130 is to be triggered based on at least one of the following: a traffic priority associated with the second transmission; a scheduling request associated with the second transmission; or a TID to link mapping associated with the second transmission.
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At block 730, the device 120 transmits, to the device 110 and via one of the first link and a second link among the multiple links, an indication that the first link is preempted for the second transmission.
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In some embodiments, the device 120 may select, as the second link, one of the multiple links that is different from the first link. In some embodiments, if a further transmission opportunity is obtained for the second link for transmission of the indication during the first transmission, the device 120 may transmit a first frame comprising the indication in the second link. In some embodiments, if the further transmission opportunity is obtained for the second link after the first transmission is finished, the device 120 may transmit a first frame comprising the indication in the second link. In some embodiments, the first frame may comprise at least one of a control frame, a management frame or a data frame.
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In some embodiments, if no transmission opportunity is obtained in the second link for transmission of the indication before the first transmission is finished, the device 120 may transmit a second frame comprising the indication in the first link after the first transmission is finished. In some embodiments, the second frame may comprise a frame for block acknowledgement of the first transmission.
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In some embodiments, the indication may comprise at least one of the following: information of the first link; information of a duration of the second transmission; information of an occasion of the second transmission; information of a priority of the second transmission; or information of whether the second transmission is associated with the first device.
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In some embodiments where the data associated with the second transmission is buffered, the device 120 may transmit the data to the third device in the first link.
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In some embodiments where the second transmission from the device 130 is to be
triggered, the device 120 may transmit, to the third device in the first link, a frame triggering the second transmission from the device 130. In some embodiments, the device 120 may receive, from the device 130 in the first link, data associated with the second transmission buffered at the device 130. In some embodiments, the device 120 may transmit, to the device 130, a frame for block acknowledgement of the second transmission.
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In some embodiments, upon determination that the second transmission is finished, the device 120 may continue performing the first transmission within remaining time of the transmission opportunity in the first link.
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In some embodiments, the preemption may be performed during a TWT SP configured for the device 130.
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With the method 700, preemption of an on-going transmission within a TXOP may be achieved. Latency reduction of a low-latency data transmission in UHR may be facilitated.
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It is to be noted that the operations of the methods 600 and 700 correspond to that described in connection with Fig. 5, and thus other details are not repeated here for conciseness.
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Example embodiments of the present disclosure also provide the corresponding apparatus. In some embodiments, an apparatus (for example, a first device as a TXOP holder) capable of performing the method 600 may comprise means for performing the respective steps of the method 600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.
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In some embodiments, the apparatus comprises: means for performing a first transmission with a second device within a transmission opportunity in a first link among multiple links established between the apparatus and the second device; means for receiving, from the second device and via one of the first link and a second link among the multiple links, an indication that the first link is preempted for a second transmission between the second device and a third device within the transmission opportunity; and means for stopping, based at least on the indication, the first transmission in the first link.
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In some embodiments, the means for receiving the indication may comprise means for receiving a first frame comprising the indication via the second link during the first transmission or after the first transmission is finished. In some embodiments, the first frame may comprise at least one of a control frame, a management frame or a data frame.
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In some embodiments, the means for receiving the indication may comprise means for receiving a second frame comprising the indication via the first link after the first transmission is finished. In some embodiments, the second frame may comprise a frame for block acknowledgement of the first transmission.
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In some embodiments, the indication may comprise at least one of the following: information of the first link; information of an occasion of the second transmission; information of a duration of the second transmission; information of a priority of the second transmission; or information of whether the second transmission is associated with the device.
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In some embodiments, the apparatus may further comprise: means for, in accordance with a determination that the second transmission is unassociated with the device, entering a sleep mode during the duration of the second transmission.
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In some embodiments, the apparatus may further comprise: means for determining that the second transmission is finished based on the information of the duration of the second transmission or the information of the occasion of the second transmission; and means for continuing performing the first transmission within remaining time of the transmission opportunity in the first link.
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In some embodiments, the means for stopping the first transmission may comprise: means for, in accordance with a determination that a priority of the second transmission is above a priority of the first transmission, stopping the first transmission.
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In some embodiments, the third device may be the apparatus.
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In some embodiments, an apparatus (for example, a second device as a non-TXOP holder) capable of performing the method 700 may comprise means for performing the respective steps of the method 700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.
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In some embodiments, the apparatus comprises: means for performing a first transmission with a first device within a transmission opportunity in a first link among multiple links established between the apparatus and the first device; means for determining that a second transmission between the second device and a third device is to be performed within the transmission opportunity; and means for transmitting, to the first device and via one of the first link and a second link among the multiple links, an indication that the first link is preempted for the second transmission.
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In some embodiments, the means for determining that the second transmission is to be performed may comprise: means for determining that data associated with the second transmission is buffered; and means for, in accordance with a determination that a priority of the second transmission is above a priority of the first transmission, determining that the second transmission is to be performed. In some embodiments, the apparatus may further comprise: means for transmitting the data to the third device in the first link.
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In some embodiments, the means for determining that the second transmission is to be performed may comprise: means for determining that the second transmission from the third device is to be triggered. In some embodiments, the determining that the second transmission from the third device is to be triggered is based on at least one of the following: a traffic priority associated with the second transmission; a scheduling request associated with the second transmission; or a traffic identifier to link mapping associated with the second transmission.
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In some embodiments, the apparatus may further comprise at least one of the following: means for transmitting, to the third device in the first link, a frame triggering the second transmission from the third device; means for receiving, from the third device in the first link, data associated with the second transmission buffered at the third device; or means for transmitting, to the third device, a frame for block acknowledgement of the second transmission.
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In some embodiments, the means for transmitting the indication may comprise: means for selecting, as the second link, one of the multiple links that is different from the first link; and means for, in accordance with a determination that a further transmission opportunity is obtained for the second link for transmission of the indication during the first transmission or after the first transmission is finished, transmitting a first frame comprising the indication in the second link. In some embodiments, the first frame may comprise at least one of a control frame, a management frame or a data frame.
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In some embodiments, the means for transmitting the indication may comprise: means for, in accordance with a determination that no transmission opportunity is obtained in the second link for transmission of the indication before the first transmission is finished, transmitting a second frame comprising the indication in the first link after the first transmission is finished. In some embodiments, the second frame may comprise a frame for block acknowledgement of the first transmission.
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In some embodiments, the indication may comprise at least one of the following: information of the first link; information of a duration of the second transmission; information of an occasion of the second transmission; information of a priority of the second transmission; or information of whether the second transmission is associated with the first device.
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In some embodiments, the apparatus may further comprise: means for determining that the second transmission is finished; and means for continuing performing the first transmission within remaining time of the transmission opportunity in the first link.
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In some embodiments, the preemption may be performed during a target wake time service period configured for the third device.
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In some embodiments, the third device may be the first device.
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Fig. 8 is a simplified block diagram of a device 800 that is suitable for implementing embodiments of the present disclosure. The device 800 may be provided to implement the communication device, for example the first device 110 or the second device 120 as shown in Fig. 1. As shown, the device 800 includes one or more processors 810, one or more memories 820 coupled to the processor 810, and one or more communication modules 840 coupled to the processor 810.
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The communication module 840 is for bidirectional communications. The communication module 840 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.
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The processor 810 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 800 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.
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The memory 820 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 824, an electrically programmable read only memory (EPROM) , a flash memory, a hard disk, a compact disc (CD) , a digital video disk (DVD) , and other magnetic storage and/or optical storage. Examples of the volatile memories
include, but are not limited to, a random access memory (RAM) 822 and other volatile memories that will not last in the power-down duration.
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A computer program 830 includes computer executable instructions that are executed by the associated processor 810. The program 830 may be stored in the ROM 820. The processor 810 may perform any suitable actions and processing by loading the program 830 into the RAM 820.
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The embodiments of the present disclosure may be implemented by means of the program 830 so that the device 800 may perform any process of the disclosure as discussed with reference to Figs. 1 to 7. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.
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In some embodiments, the program 830 may be tangibly contained in a computer readable medium which may be included in the device 800 (such as in the memory 820) or other storage devices that are accessible by the device 800. The device 800 may load the program 830 from the computer readable medium to the RAM 822 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. Fig. 9 shows an example of the computer readable medium 900 in form of CD or DVD. The computer readable medium has the program 830 stored thereon.
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Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.
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The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry
out the method 600 or 700 as described above with reference to Figs. 6 and 7. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.
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Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.
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In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.
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The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. The term “non-transitory, ” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM) .
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Further, while operations are depicted in a particular order, this should not be
understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.
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Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.