WO2022133758A1

WO2022133758A1 - Enhancement on autonomous retransmission

Info

Publication number: WO2022133758A1
Application number: PCT/CN2020/138459
Authority: WO
Inventors: Renato BARBOSA ABREU; Tao Tao; Hua Chao
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2020-12-23
Filing date: 2020-12-23
Publication date: 2022-06-30
Also published as: CN116724514A

Abstract

Embodiments of the present disclosure relate to enhancement on autonomous retransmission. A method comprises in accordance with a determination that a traffic is to be transmitted, transmitting, at a first device, the traffic to a second device on a first resource configured for initial transmission; starting a timer configured for retransmission; in accordance with a determination that the timer expires, activating a second resource configured for the retransmission; and retransmitting the traffic on the activated second resource. The method further comprises: receiving, at the second device, the traffic on the first resource; in accordance with a determination that a feedback or a grant is not transmitted successfully, determining the activated second resource; and receiving the traffic retransmitted on the activated second resource. In this way, a drifting of periodic TSC transmissions can be avoided and a dedicated resource for retransmission can be flexibly configured.

Description

ENHANCEMENT ON AUTONOMOUS RETRANSMISSION

FIELD

Embodiments of the present disclosure generally relate to the field of telecommunication and, in particular, to a method, device and computer readable storage medium of communication for autonomous retransmission.

BACKGROUND

The fifth generation (5G) new radio (NR) introduces a support for industrial internet of things (IIoT) services including time sensitive communication (TSC) applications in Release 16. TSC traffic is typically characterized by periodic deterministic transmissions which should be delivered in strict latency bounds. In this case, configured grant (CG) resources are scheduled in alignment with the TSC traffic allowing deterministic transmissions in a radio access network (RAN) .

Autonomous retransmission is introduced in NR for unlicensed band operation (NR-U) based on a cg-Retransmission Timer for a hybrid automatic repeat request (HARQ) process of a CG transmission. Specifically, if a terminal device does not receive a dynamic grant or an acknowledgement (ACK) for the HARQ process until the timer expires, the terminal device interprets as non-acknowledgement (NACK) for the CG transmission. Then the terminal device performs a retransmission for the HARQ process in a CG resource. If there is a new packet to be transmitted, the retransmission should be prioritized. Such usage of the CG resource for autonomous retransmission as in NR-U operation will be unfavorable for the deterministic transmissions of TSC traffic, as the CG resource is used for the retransmission of one pervious packet of the TSC traffic and no resource can be used to transmit a new packet of the TSC traffic. Thus, subsequent transmissions of the TSC traffic will be delayed.

SUMMARY

In general, example embodiments of the present disclosure provide an improved solution for autonomous retransmission.

In a first aspect, there is provided a first device. The first device comprises: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code are configured to, with the at least one processor, cause the first device to: in accordance with a determination that a traffic is to be transmitted, transmit the traffic to a second device on a first resource configured for initial transmission of the traffic; start a timer configured for retransmission of the traffic; in accordance with a determination that the timer expires, activate a second resource configured for the retransmission; and retransmit the traffic on the activated second resource.

In a second aspect, there is provided a second device. The second device comprises: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code are configured to, with the at least one processor, cause the second device to: receive, from a first device, a traffic on a first resource configured for initial transmission of the traffic; in accordance with a determination that a hybrid automatic repeat request feedback for the initial transmission or a grant for retransmission of the traffic is not transmitted successfully, determine an activated second resource configured for retransmission of the traffic; and receive, from the first device, the traffic retransmitted on the activated second resource.

In a third aspect, there is provided a method of communication. The method comprises: in accordance with a determination that a traffic is to be transmitted, transmitting, at a first device, the traffic to a second device on a first resource configured for initial transmission of the traffic; starting a timer configured for retransmission of the traffic; in accordance with a determination that the timer expires, activating a second resource configured for the retransmission; and retransmitting the traffic on the activated second resource.

In a fourth aspect, there is provided a method of communication. The method comprises: receiving, at a second device and from a first device, a traffic on a first resource configured for initial transmission of the traffic; in accordance with a determination that a hybrid automatic repeat request feedback for the initial transmission or a grant for retransmission of the traffic is not transmitted successfully, determining an activated second resource configured for retransmission of the traffic; and receiving, from the first device, the traffic retransmitted on the activated second resource.

In a fifth aspect, there is provided an apparatus of communication. The apparatus comprises: means for in accordance with a determination that a traffic is to be transmitted, transmitting, at a first device, the traffic to a second device on a first resource configured for initial transmission of the traffic; means for starting a timer configured for retransmission of the traffic; means for in accordance with a determination that the timer expires, activating a second resource configured for the retransmission; and means for retransmitting the traffic on the activated second resource.

In a sixth aspect, there is provided an apparatus of communication. The apparatus comprises: means for receiving, at a second device and from a first device, a traffic on a first resource configured for initial transmission of the traffic; means for in accordance with a determination that a hybrid automatic repeat request feedback for the initial transmission or a grant for retransmission of the traffic is not transmitted successfully, determining an activated second resource configured for retransmission of the traffic; and means for receiving, from the first device, the traffic retransmitted on the activated second resource.

In a seventh aspect, there is provided a non-transitory computer readable medium. The non-transitory computer readable medium comprises program instructions for causing an apparatus to perform the method according to the third aspect.

In an eighth aspect, there is provided a non-transitory computer readable medium. The non-transitory computer readable medium comprises program instructions for causing an apparatus to perform the method according to the fourth aspect.

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

Some example embodiments will now be described with reference to the accompanying drawings, where:

Fig. 1 illustrates an example communication network in which example embodiments of the present disclosure may be implemented;

Fig. 2 illustrates a diagram of an autonomous retransmission using a periodic transmission occasion according to a conventional solution;

Fig. 3 illustrates a flowchart illustrating a process of communication according to some embodiments of the present disclosure;

Fig. 4 illustrates a diagram of an autonomous retransmission using a dedicated resource according to some embodiments of the present disclosure;

Fig. 5 illustrates a flowchart of a method of communication implemented at a first device according to example embodiments of the present disclosure;

Fig. 6 illustrates a flowchart of a method of communication implemented at a second device according to example embodiments of the present disclosure;

Fig. 7 illustrates a simplified block diagram of an apparatus that is suitable for implementing example embodiments of the present disclosure; and

Fig. 8 illustrates a block diagram of an example computer readable medium in accordance with example embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle 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.

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.

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.

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. These terms are only used 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.

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 in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable) :

(i) a combination of analog and/or digital hardware circuit (s) with software/firmware and

(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

(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.

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.

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as fifth generation (5G) systems, 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) new radio (NR) communication protocols, 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.

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 network device 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 NB (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. A RAN split architecture comprises a gNB-CU (Centralized unit, hosting RRC, SDAP and PDCP) controlling a plurality of gNB-DUs (Distributed unit, hosting RLC, MAC and PHY) . A relay node may correspond to DU part of the IAB node.

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 (loT) 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, and the like. The terminal device may also correspond to Mobile Termination (MT) part of the integrated access and backhaul (IAB) node (a.k.a. a relay node) . In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.

TSC application demands high reliability and availability of the network. For supporting such kind of application, NR Release 16 for IIOT introduces TSC assistance information (TSCAI) which describes TSC traffic characteristics for use in the 5G system. The TSCAI provides information about the traffic flow direction (uplink (UL) or downlink (DL) ) , the periodicity and the burst arrival time, together with other information from a quality of service (QoS) profile which gives information about the TSC burst size and packet delay budget, that gives knowledge of TSN traffic pattern. This allows a network device to more efficiently schedule periodic, deterministic traffic flows either via CG, semi-persistent scheduling (SPS) or with dynamic grants. A TSC traffic associated to a certain QoS flow and logical channel can be allowed to use one or more specific CGs with proper resource configuration which can satisfy the reliability requirement (e.g. with resource allocation, periodicity and time offset matching with the traffic pattern) to leverage the data (allowedCG-List) .

In unlicensed bands, supporting mission-critical services such as ultra-reliable low-latency communication (URLLC) and TSC may be very challenging since unexpected interference may prevent the transmissions to occur due to listen-before-talk (LBT) failures when accessing the channel using clear channel assessment (CCA) procedure. Thus, it is expected to support URLLC and TSC in unlicensed bands.

To fulfill the availability requirement, a survival time is introduced in Release 17. The survival time indicates the time that an application consuming a communication service may continue without an anticipated message. Thus, it is also expected to support fulfilling new QoS parameters such as the survival time.

NR-U supports uplink CG including also multiple active CG per bandwith part and configuration of allowed CG per logical channel. Differently from NR CG, NR-U CG includes features for overcoming LBT issues and gives more autonomy for a terminal device on handling the HARQ processes. In NR-U CG, a terminal device selects a HARQ process number (HPN) , redundancy version (RV) and new data indicator (NDI) value and informs them in CG-uplink control information (UCI) during a transmission in a CG-physical uplink shared channel (PUSCH) resource. Additionally, channel occupation time (COT) sharing information can also be included in the CG-UCI.

As mentioned above, autonomous retransmission is introduced in NR-U based on a cg-RetransmissionTimer for a HARQ process of a CG transmission. If a terminal device does not receive a dynamic grant or an ACK for the HARQ process until the timer expires, the terminal device interprets as NACK for the CG transmission. Then the terminal device performs a retransmission for the HARQ process in a CG resource. If there is a new packet to be transmitted, the retransmission should be prioritized.

On the other hand, in NR URLLC CG designed for licensed band operation, autonomous retransmissions are not supported. If a terminal device does not receive a retransmission grant from a network device, the terminal device assumes ACK for the CG transmission. The underlying assumption is that the network device may be able to at least detect UL transmission with high probability (e.g.: by demodulation reference signal (DMRS) detection) and schedule a retransmission if a packet is not decoded correctly. HARQ process ID for URLLC CG transmission is defined based on the timing of the transmission. In licensed spectrum, such behavior is fine since there is no limitation in terms of channel access (no LBT restriction) for the network device to signal the terminal device if a retransmission grant is needed.

For IIOT where the CG configuration is associated with a periodic TSC traffic flow, the CG resources should be scheduled in alignment with the traffic allowing the deterministic transmissions in RAN. In addition, one (repeated) TB can be configured and transmitted within one period of the CG.

The usage of CG resource for autonomous retransmission as in NR-U operation is not favorable for the deterministic TSC transmissions. That is because the CG resource aligned with TSC traffic will not be dedicated for initial transmission of the TSC traffic, potentially drifting the transmission and causing latency violation if another grant or feedback is not provided promptly by the network device before the timer expires.

In order to solve the above and other potential problems, embodiments of the present disclosure provide an improved solution. In the solution, a dedicated resource is configured for an autonomous retransmission, and the dedicated resource is activated to be used for retransmission when a timer configured for retransmission expires. In this way, a drifting of periodic TSC transmissions can be avoided in case an autonomous retransmission is needed, while a flexible configuration of a dedicated resource for CG retransmission can be achieved. Principles and implementations of the present disclosure will be described in detail below with reference to the figures.

Fig. 1 illustrates an example communication network 100 in which embodiments of the present disclosure can be implemented. As shown in Fig. 1, the network 100 includes a first device 110 and a second device 120 serving the first device 110. It is to be understood that the number of first and second devices as shown in Fig. 1 is only for the purpose of illustration without suggesting any limitations. The network 100 may include any suitable number of first and second devices adapted for implementing embodiments of the present disclosure. In some embodiments, the first device 110 may be a terminal device, and the second device 120 may be a network device.

Merely for illustration purpose and without suggesting any limitations as to the scope of the present disclosure, some embodiments will be described in the context where the first device 110 is a terminal device and the second device 120 is a network device. It is to be understood that, in other embodiments, the first device 110 may be a network device and the second device 120 may be a terminal device. In other words, the principles and spirits of the present disclosure can be applied to both uplink and downlink transmissions.

As shown in Fig. 1, the first device 110 and the second device 120 may communicate with each other. The first device 110 may have multiple antennas for communication with the second device 120. The second device 120 may also have multiple antennas for communication with the first device 110. It is to be understood that each of the first device 110 and the second device 120 may provide any suitable number of antennas adapted for implementing embodiments of the present disclosure.

The communications in the network 100 may conform to any suitable standards including, but not limited to, LTE, LTE-evolution, LTE-advanced (LTE-A) , wideband code division multiple access (WCDMA) , code division multiple access (CDMA) and global system for mobile communications (GSM) and the like. Furthermore, the communications may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, 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) communication protocols.

In some scenarios, the first device 110 may have a traffic to be transmitted to the second device 120, for example, a periodic traffic such as URLLC or TSC traffic. In a conventional solution, CG resources are scheduled in alignment or in-sync with the periodic traffic, and the terminal device retransmits in a CG resource configured for both initial transmission and retransmission after a timer configured for retransmission expires. Fig. 2 illustrates a diagram 200 of an autonomous retransmission using a periodic transmission occasion according to a conventional solution. For convenience, assuming that the length of the timer is one period of the periodic traffic in this example.

As shown in Fig. 2,

periodic traffics

210, 211, 212 and 213 are to be transmitted.

CG resources

220, 221, 222 and 223 are scheduled for respective transmissions of

periodic traffics

210, 211, 212 and 213. The periodic traffic 210 is transmitted via the CG resource 220. In this example, a HARQ feedback for the transmission of the periodic traffic 210 is received within a period of the periodic traffic. In this case, when the periodic traffic 211 arrivals, the periodic traffic 211 can be transmitted via the CG resource 221.

Assuming that no HARQ feedback for the transmission of the periodic traffic 211 is received within the period of the periodic traffic, i.e., upon expiration of the timer. In this case, the periodic traffic 211 should be retransmitted. According to the conventional solution, the retransmission is prioritized. Thus, the retransmission of the periodic traffic 211 will be performed via the CG resource 222. As a result, when the periodic traffic 212 arrivals, no resource can be used for transmission of the periodic traffic 212, and the periodic traffic 212 may be delayed to be transmitted via the CG resource 223. As such, when the periodic traffic 213 arrivals, no resource can be used for transmission of the periodic traffic 213, and the periodic traffic 213 may also be delayed.

It can be seen that the retransmission occurs in a resource which was expected to be used for the deterministic transmission, potentially delaying the subsequent transmissions. More specifically, if the CG resource is used for autonomous retransmission of one previous transport block (TB) , there is no resource to transmit latest new coming traffic. Thus, in this solution, the retransmissions always have a higher priority and would block initial transmission for new packet.

In another conventional solution, LTE UL HARQ mechanism using synchronous HARQ may be used. In this mechanism, the terminal device may retransmit the traffic after a predefined number of subframes, e.g., 8 subframes. However, such fix retransmission will cause unnecessary resource waste.

As still another conventional solution, an obvious way to avoid the above issue could be to not configure the cg-RetransmissionTimer. However, if the effect of LBT failures is not negligible, deactivating the timer-based retransmission will degrade the reliability, since the network device may not be always able to timely provide a retransmission grant if LBT failures occur.

Another way could be configuring more CG resources, for example, with double of periodicity, or by an extra CG configuration for the same traffic flow. This way can give more occasions for the terminal device to fit its transmission and retransmission. However, such overprovision solution is inefficient.

In view of this, embodiments of the present disclosure provide a solution of configuring a dedicated resource for autonomous retransmission. This mechanism of the present disclosure is illustrated in a high-level flowchart as shown in Fig. 3. Fig. 3 illustrates a flowchart illustrating a process 300 of communication according to some embodiments of the present disclosure. For convenience, Fig. 3 will be described in connection with the example of Fig. 1.

As shown in Fig. 3, the second device 120 may transmit 301, to the first device 110, a first configuration indicating a first resource configured for initial transmission of a traffic and a second configuration indicating a second resource configured for retransmission of the traffic. In some embodiments where the traffic is a periodic traffic, the first resource may comprise a set of periodic resources, and each resource in the set of periodic resources is associated with a certain period or HARQ process. In these embodiments, the second resource may also comprise a set of periodic resources, and each resource in the set of periodic resources is associated with a certain period or HARQ process.

In some embodiments, the first configuration may comprise an index of the first resource, for example, a configured grant index of the first resource. Of course, any other suitable ways are also feasible and the present disclosure does not make limitation for the first configuration.

In some embodiments, the second configuration may comprise a separate offset (denoted as autoReTXtimeDomainOffset herein) for autonomous retransmission resource. In some embodiments, the offset may be an offset of the second resource with respect to the first resource in time domain. For example, the offset may be defined in the number of symbols between the first symbol of CG PUSCH and the first symbol of retransmission PUSCH. In some alternative embodiments, the offset may also be an offset of the second resource with respect to the first resource in frequency domain.

In some alternative embodiments, the offset may be an offset of the second resource with respect to a time reference system frame number (also referred to as timeReferenceSFN herein) . For example, the offset may be defined as an offset in the number of symbols with respect to the timeReferenceSFN. The timereferenceSFN indicates a system frame number (SFN) used for determination of an offset of a resource in time domain. In some embodiments, the timeReferenceSFN may be the closest SFN with the indicated number preceding the reception of the configured grant configuration. In some embodiments where the field timeReferenceSFN is no present, the timeReferenceSFN may be 0.

In some alternative embodiments, the second configuration may comprise an index (denoted as cg-autoReTXCGConfigIndex herein) of the second resource. For example, the index may be a configured grant index of the second resource. The configured grant index indicates an index of a configured grant configuration of the second resource. In some embodiments, the configured grant index may indicate an index of a configured grant configuration of the second resource within a bandwidth part (BWP) associated with the first device 110. In some embodiments, the configured grant index may indicate an index of a configured grant configuration of the second resource within a media access control (MAC) entity of the first device 110.

In some embodiments, the second device 120 may transmit the first and second configurations in the same higher layer signaling such as a radio resource control (RRC) message. In some alternative embodiments, the second device 120 may transmit the first and second configurations in separate or different higher layer signaling. For example, the second device 120 may transmit the second configuration through an extra CG configuration indicated for the retransmission of the traffic. In other words, such extra CG configuration is added to allowedCG-List and marked or indicated as for retransmission. In some embodiments, the indication may be in the CG configuration. Of course, the indication may also be along the CG index in the allowedCG-List.

In some embodiments, other radio resource management (RRM) parameters such as frequency domain allocation for the retransmission may be the same as of the initial transmission. In some alternative embodiments, the other RRM parameters can be also configured along with the second configuration.

In some embodiments, the second resource may comprise a set of resources. In other words, multiple retransmission resources may be provided. In some embodiments, the multiple retransmission resources may be provided by associating multiple time offsets autoReTXtimeDomainOffset-N. In some embodiments, each retransmission may occur after autoReTXtimeDomainOffset-N from the previous transmission attempt if the timer has expired.

Accordingly, the first device 110 may receive the first and second configurations and then obtain the first and second resource. When a new packet of the traffic arrivals, the first device 110 may transmit 302 the packet via the first resource to the second device 120 (also referred to as initial transmission herein) . The first device 110 may start 303 a timer configured for retransmission of the traffic. For example, the timer may be a cg-RetransmissionTimer. Of course, any other suitable forms of the timer are also feasible. In some embodiments, the timer may be started upon the initial transmission of the packet. In some embodiments, the timer may be started before the next initial transmission of upcoming packet. It is to be understood that the timer may be started at any time point after the current initial transmission and before the next initial transmission. In this way, if the timer is set to equal to the period of the first resource or multiple of the period of the first resource, the timer cannot expire prior to an upcoming periodic occasion of the first resource and the first device 110 may automatically determine to transmit a new initial transmission in the first resource, while upcoming second resource is deemed for retransmission.

In some embodiments, the first device 110 may stop the timer upon receipt of a HARQ feedback for the initial transmission from the second device 120. In some embodiments, the first device 110 may stop the timer upon receipt of a grant for the retransmission from the second device 120.

In some embodiments, a length of the timer may be set to be equal to a period of the first resource. In some alternative embodiments, the length of the timer may be set to be multiple of the period of the first resource. According to embodiments of the present disclosure, the retransmission occurs in a resource not overlapping with the occasion used for the deterministic TSC transmission. Thus, in some alternative embodiments, the length of the timer may be set to be lower than the period of the first resource. For example, the length of the timer may be set to be a fraction of the period of the first resource. In this way, a retransmission is allowed to occur before the next TSC transmission occasion if a time offset is also below one period. In this case, the timer needs to be specified with lower granularity, e.g., in number of symbols, since the timer is in integer number of periods in a conventional solution.

Upon receipt of the traffic on the first resource, the second device 120 may transmit 304 a HARQ feedback for the initial transmission or a grant for retransmission to the first device 110. In some embodiments, if the second device 120 decodes the traffic correctly, the second device 120 may transmit a HARQ ACK to the first device 110. In some embodiments, if the second device 120 cannot decode the traffic, the second device 120 may transmit a HARQ NACK to the first device 110. Alternatively, the second device 120 may schedule a grant for retransmission of the traffic by the first device 110.

In some embodiments where the second device 120 transmits the HARQ feedback or the grant successfully, the second resource is not activated for retransmission. That is, the second resource is not reserved for retransmission. In this case, the second device 120 may use 305 the second resource for other purpose. For example, the second device 120 may schedule the unactivated second resource for DL transmission. In this way, the second resource may be reserved when necessary, and thus resource utilization can be improved.

In some embodiments, the second device 120 may not transmit the HARQ feedback or the grant successfully due to LBT failure or any other factors. In this case, if no HARQ feedback for the initial transmission or grant for retransmission is received until the timer expires, the first device 110 may retransmit 306 the packet of the traffic on the second resource. In some embodiments, when autonomous retransmission resource is configured by the second device 120, the second device 120 expects the first device 110 to retransmit on the additional or dedicated resource configured for retransmission when not able to send a grant or feedback to the first device 110 (e.g., due to LBT failure) before CG retransmission timer expires. In some embodiments, if the HARQ feedback or the grant is not transmitted successfully, the second device 120 may determine whether the second resource is activated. When the second resource is activated, the second device 120 can receive the retransmitted traffic on the second resource.

In some embodiments, when the timer expires, the first device 110 may activate the second resource and retransmit the packet of the traffic on the activated second resource. In other words, upon expiration of the timer, the second resource may be reserved for retransmission. In some embodiments, the second resource may be activated when the timer expires. In some alternative embodiments, if the initial transmission in the first resource is cancelled due to the transmission of a higher priority traffic in a resource overlapping with the first resource, the first device 110 may activate the second resource. In other words, if the initial transmission of the traffic and the transmission of the higher priority traffic are overlapped in time domain, the first device 110 may cancel the initial transmission. Upon cancelling the initial transmission, the first device 110 may activate the second resource. In this way, the first device 110 may use the activated second resource for transmitting the cancelled transmission. In some embodiments where the cg-RetransmissionTimer is not restarted after each retransmission, the first device 110 may keep the whole CG configuration of the second resource active (i.e., all the next periodic retransmission resources) upon expiration of the timer. In some embodiments where the cg-RetransmissionTimer is restarted in each retransmission attempt, the first device 110 may activate one upcoming second resource upon expiration of the timer.

In this way, the first device 110 may perform autonomous retransmission on the activated second resource. For clarity, this will be further described with reference to Fig. 4. Fig. 4 illustrates a diagram 400 of an autonomous retransmission using a dedicated resource according to some embodiments of the present disclosure.

As shown in Fig. 4,

periodic traffics

410, 411, 412 and 413 are to be transmitted.

First resources

420, 421, 422 and 423 are configured for respective transmissions of

periodic traffics

410, 411, 412 and 413.

Second resources

431, 432 and 433 are configured for respective retransmissions corresponding to initial transmissions of the

periodic traffics

410, 411 and 412 on the

first resources

420, 421 and 422. Second resource 430 is configured for retransmission corresponding to initial transmission of a periodic traffic (not shown) preceding the periodic traffic 410. For convenience, assuming that the length of the timer is one period of the first resource in this example.

Initially, the periodic traffic 410 is transmitted via the first resource 420. Meanwhile, a timer configured for retransmission of the periodic traffic 410 is started. In this example, a HARQ feedback for the initial transmission of the periodic traffic 410 is received within a period of the periodic traffic. In this case, the timer is stopped and is not expired, and thus the second resource 431 is not activated, i.e., the second resource 431 is inactive. When the periodic traffic 411 arrivals, the periodic traffic 411 is transmitted via the first resource 421.

In this example, no HARQ feedback for the initial transmission of the periodic traffic 411 is received until the timer expires. In this case, the first device 110 activates the second resource 432 to retransmit the periodic traffic 411. When the periodic traffic 412 arrivals, the periodic traffic 412 can also be transmitted via the first resource 422. As such, autonomous retransmissions can be performed without affecting or delaying subsequent transmissions of the periodic traffic.

In some embodiments, the first device 110 may determine an identifier of a HARQ process (also referred to as HARQ process ID herein) associated with the initial transmission, and perform the retransmission with the HARQ process ID. In other words, the HARQ process ID used in the activated second resource for retransmission is the same to the associated CG resource for initial transmission.

In some alternative embodiments, the first device 110 may derive the HARQ process ID associated with the initial transmission by itself based on CG configuration parameters. In some embodiments where configured uplink grants configured with cg-RetransmissionTimer and autoReTXtimeDomainOffset, the first device 110 may derive the HARQ process ID associated with the first symbol of an autonomous UL retransmission at least based on a length of the timer (e.g., cg-RetransmissionTimer) , a period of the first resource (e.g., periodicity) , and an offset of the second resource with respect to the first resource (e.g., autoReTXtimeDomainOffset) .

For example, the HARQ process ID may be derived from equation (1) in combination with equation (2) below.

HARQ Process ID = [floor (CURRENT_symbol /periodicity) ] modulo nrofHARQ-Processes + harq-ProcID-Offset2 (1)

CURRENT_symbol = (SFN × numberOfSlotsPerFrame × numberOfSymbolsPerSlot + slot number in the frame × numberOfSymbolsPerSlot + symbol number in the slot –cg-RetransmissionTimer × periodicity –autoReTXtimeDomainOffset) (2)

where nrofHARQ-Processes denotes the number of configured HARQ processes for SPS, harq-ProcID-Offset2 denotes an offset of the HARQ process for CG, periodicity denotes the period of the first resource, and numberOfSlotsPerFrame and numberOfSymbolsPerSlot denote the number of consecutive slots per frame and the number of consecutive symbols per slot, respectively. It is to be understood that the above equations are merely examples, and any other suitable forms are also feasible.

In some embodiments where configured uplink grants configured with cg-RetransmissionTimer and an extra configured uplink grant for retransmission, the second device 120 may configure the parameters of harq-ProcID-Offset2 for both initial transmission and retransmission to make sure that the first device 110 can derive the same HPN.

In some embodiments, the first device 110 may transmit the HARQ process ID to the second device 120. For example, the first device 110 may transmit uplink control information (UCI) for CG to indicate a HARQ process number (HPN) of the retransmission from the initial transmission and not toggle a new data indicator (NDI) . In this way, the second device 120 can know whether the current transmission is a transmission or a retransmission of data in a certain HARQ process, and thus can perform a soft combining to improve the decoding of the data.

In some embodiments, if the first device 110 receives a HARQ ACK for the retransmission from the second device 120, the first device 110 may deactivate the second resource. For example, the first device 110 may not reserve the second resource. In some alternative embodiments, if a timer (also referred to as configuredGrant Timer herein) configured for a HARQ process associated with the initial transmission expires, the first device 110 may also deactivate the second resource. In some embodiments, the configuredGrant Timer may be used to flush a buffer of the correspondent HARQ process. In some embodiments, the configuredGrant Timer may be started in the beginning of the initial transmission. In some embodiments, the configuredGrant Timer may be stopped if the first device 110 receives a HARQ feedback for the transmission or retransmission of correspondent HARQ process. In some embodiments, the value of the configuredGrant Timer may be set to be equal to or larger than that of the cg-RetransmissionTimer.

With the process described in Fig. 3, a drifting of periodic TSC transmissions can be avoided in case an autonomous retransmission is needed, while a flexible configuration of a dedicated resource for CG retransmission can be achieved. The implicit activation of the resource linked to the timer configured for retransmission is also more efficient than CG overprovision, since in an implementation the retransmission resource may be reserved when the second device 120 is not able to send the feedback or grant to the first device 110 e.g., due to LBT failure, assuming that the second device 120 detects the initial transmission though not necessarily able to decode the initial transmission.

Corresponding to the above process, some example embodiments of the present disclosure will now be described in detail with reference to the figures. However, those skilled in the art would readily appreciate that the detailed description given herein with respect to these figures is for explanatory purpose as the present disclosure extends beyond theses limited embodiments.

Fig. 5 illustrates a flowchart of a method 500 of communication implemented at a first device according to example embodiments of the present disclosure. The method 500 can be implemented at the first device 110 shown in Fig. 1. For the purpose of discussion, the method 500 will be described with reference to Fig. 1. It is to be understood that method 500 may further include additional blocks not shown and/or omit some shown blocks, and the scope of the present disclosure is not limited in this regard.

As shown in Fig. 5, at block 510, the first device 110 determines whether a traffic is to be transmitted. In some embodiments, the traffic may be a periodic traffic. For example, the periodic traffic may be STC traffic. It is to be understood that any other suitable traffic is also feasible.

If determining that the traffic is to be transmitted, at block 520, the first device 110 transmits the traffic to the second device 120 on a first resource configured for initial transmission of the traffic. In some embodiments, the first device 110 may further receive a first configuration indicating the first resource and a second configuration indicating the second resource from the second device 120. In some embodiments, the first device 110 may receive the first and second configurations in a higher layer signaling. In some embodiments, the first device 110 may receive the first and second configurations in separate higher layer signaling. In some embodiments, the second configuration may comprise at least one of the following: an offset of the second resource with respect to the first resource; an offset of the second resource with respect to a time reference system frame number; or a configured grant index of the second resource. In some embodiments, the second resource may comprise a set of resources, and the offset comprises a set of offset values for the set of resources.

Upon the initial transmission of the traffic on the first resource, at block 530, the first device 110 starts a timer configured for retransmission of the traffic. In some embodiments, the first device 110 may stop the timer upon receipt of a HARQ feedback for the initial transmission from the second device 120. In some embodiments, the first device 110 may stop the timer upon receipt of a grant for retransmission from the second device 120. In some embodiments, a length of the timer may be set to be equal to or lower than a period of the first resource.

At block 540, the first device 110 determines whether the timer expires. If determining that the timer expires, that is, the first device 110 determines no HARQ feedback for the initial transmission or grant for retransmission is received from the second device 120 until the timer expires, the process proceeds to block 550.

At block 550, the first device 110 activates a second resource configured for the retransmission. In some embodiments, upon expiration of the timer, the first device 110 may activate the second resource. In some alternative embodiments, if the initial transmission in the first resource is cancelled due to the transmission of a higher priority traffic in a resource overlapping with the first resource, the first device 110 may activate the second resource. In this way, the first device 110 may use the activated second resource for transmitting the cancelled transmission. In some embodiments where the cg-RetransmissionTimer is not restarted after each retransmission, the first device 110 may keep the whole CG configuration of the second resource active (i.e., all the next periodic retransmission resource) upon expiration of the timer. In some embodiments where the cg-RetransmissionTimer is restarted in each retransmission attempt, the first device 110 may activate one upcoming second resource upon expiration of the timer.

At block 560, the first device 110 retransmits the traffic on the activated second resource. In some embodiments, the first device 110 may retransmit the traffic by determining an identifier of a HARQ process associated with the initial transmission, and performing the retransmission with the identifier. In some embodiments, the first device 110 may determine the identifier based on a length of the timer, a period of the first resource, and an offset of the second resource with respect to the first resource.

In some embodiments, if the first device 110 receives a HARQ feedback indicating that the traffic is received by the second device 120 successfully, the first device 110 may deactivate the second resource. In some embodiments, if a timer (for example, configuredGrant Timer) configured for a HARQ process associated with the initial transmission expires, the first device 110 may deactivate the second resource.

The operations in the method of Fig. 5 correspond to that in the process described in Fig. 3, and thus other details are omitted here for concise. With the method of Fig. 5, a dedicated resource is used for retransmission and a delay of subsequent initial transmission can be avoided.

Correspondingly, embodiments of the present disclosure also provide a method of communication implemented at a second device. Fig. 6 illustrates a flowchart of a method 600 of communication implemented at a second device according to example embodiments of the present disclosure. The method 600 can be implemented at the second device 120 shown in Fig. 1. For the purpose of discussion, the method 600 will be described with reference to Fig. 1. It is to be understood that method 600 may further include additional blocks not shown and/or omit some shown blocks, and the scope of the present disclosure is not limited in this regard.

As shown in Fig. 6, at block 610, the second device 120 receives a traffic on a first resource configured for initial transmission of the traffic from the first device 110. In some embodiments, the second device 120 may transmit a first configuration indicating the first resource and a second configuration indicating the second resource. In some embodiments, the second device 120 may transmit the first and second configurations in a higher layer signaling such as a RRC message. In some embodiments, the second device 120 may transmit the first and second configurations in separate higher layer signaling. In some embodiments, the second configuration may comprise at least one of the following: an offset of the second resource with respect to the first resource; an offset of the second resource with respect to a time reference system frame number; or a configured grant index of the second resource.

At block 620, the second device 120 determines whether a HARQ feedback for the initial transmission or a grant for retransmission of the traffic is transmitted successfully.

In some embodiments, if the second device 120 decodes the traffic correctly, the second device 120 may transmit a HARQ ACK to the first device 110. In some embodiments, if the second device 120 cannot decode the traffic, the second device 120 may transmit a HARQ NACK to the first device 110. Alternatively, the second device 120 may schedule a grant for retransmission of the traffic by the first device 110. In some embodiments, the second device 120 may not transmit the HARQ feedback or the grant successfully due to LBT failure or any other factors.

If determining that the HARQ feedback for the initial transmission or the grant for retransmission of the traffic is not transmitted successfully, at block 630, the second device 120 determines an activated second resource configured for retransmission of the traffic. In other words, if the HARQ feedback for the initial transmission or the grant for retransmission of the traffic is not transmitted successfully, the second device 120 may determine that the second resource is activated. In some embodiments where the cg-RetransmissionTimer is restarted in each retransmission attempt, the second device 120 may determine one upcoming activated second resource. In some embodiments where the cg-RetransmissionTimer is not restarted after each retransmission, the second device 120 may determine that all the next periodic retransmission resources are activated.

At block 640, the second device 120 receives the traffic retransmitted on the activated second resource. In some embodiments, if the HARQ feedback for the initial transmission or the grant for the retransmission is transmitted successfully, the second device 120 may configure the second resource for other transmission than the retransmission. In other words, the second resource is not reserved for the retransmission. In this way, the resource utilization can be improved.

The operations in the method of Fig. 6 correspond to that in the process described in Fig. 3, and thus other details are omitted here for concise. With the method of Fig. 6, a dedicated resource for retransmission can be flexibly configured and can be reserved when needed. Thus, resource utilization is efficient.

In some embodiments, an apparatus (for example, the first device 110) capable of performing the method 500 may comprise means for performing the respective steps of the method 500. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some embodiments, the apparatus may comprise: means for in accordance with a determination that a traffic is to be transmitted, transmitting, at a first device, the traffic to a second device on a first resource configured for initial transmission of the traffic; means for starting a timer configured for retransmission of the traffic; means for in accordance with a determination that the timer expires, activating a second resource configured for the retransmission; and means for retransmitting the traffic on the activated second resource.

In some embodiments, the means for activating may comprise means for in accordance with a determination that the initial transmission in the first resource is cancelled due to the transmission of a higher priority traffic in a resource overlapping with the first resource, activating the second resource for transmission of the cancelled transmission.

In some embodiments, the apparatus may further comprise: means for receiving, from the second device, a first configuration indicating the first resource and a second configuration indicating the second resource. In some embodiments, the second configuration may comprise at least one of the following: an offset of the second resource with respect to the first resource; an offset of the second resource with respect to a time reference system frame number; or a configured grant index of the second resource. In some embodiments, the second resource may comprise a set of resources, and the offset may comprise a set of offset values for the set of resources.

In some embodiments, the means for receiving may comprise: means for receiving the first and second configurations in a higher layer signaling, or means for receiving the first and second configurations in separate higher layer signaling.

In some embodiments, the means for retransmitting may comprise: means for determining an identifier of a HARQ process associated with the initial transmission; and means for performing the retransmission with the identifier. In some embodiments, the means for determining may comprise means for determining the identifier at least based on a length of the timer, a period of the first resource, and an offset of the second resource with respect to the first resource. In some embodiments, a length of the timer may be set to be equal to or lower than a period of the first resource.

In some embodiments, the apparatus may further comprise means for receiving a HARQ feedback for the retransmission from the second device; and means for in accordance with a determination that the HARQ feedback indicates that the traffic is received by the second device successfully, deactivating the second resource. In some embodiments, the apparatus may further comprise means for in accordance with a determination that a timer configured for a HARQ process associated with the initial transmission expires, deactivating the second resource.

In some embodiments, an apparatus (for example, the second device 120) 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.

In some embodiments, the apparatus may comprise: means for receiving, at a second device and from a first device, a traffic on a first resource configured for initial transmission of the traffic; means for in accordance with a determination that a HARQ feedback for the initial transmission or a grant for retransmission is not transmitted successfully, determining an activated second resource configured for retransmission of the traffic; and means for receiving, from the first device, the traffic retransmitted on the activated second resource.

In some embodiments, the apparatus may further comprise: means for transmitting, to the first device, a first configuration indicating the first resource and a second configuration indicating the second resource. In some embodiments, the second configuration may comprise at least one of the following: an offset of the second resource with respect to the first resource; an offset of the second resource with respect to a time reference system frame number; or a configured grant index of the second resource. In some embodiments, the second resource may comprise a set of resources, and the offset may comprise a set of offset values for the set of resources.

In some embodiments, the means for transmitting may comprise: means for transmitting the first and second configurations in a higher layer signaling, or means for transmitting the first and second configurations in separate higher layer signaling.

In some embodiments, the apparatus may further comprise: means for in accordance with a determination that the HARQ feedback for the initial transmission is transmitted successfully, scheduling the second resource for other transmission than the retransmission.

FIG. 7 is a simplified block diagram of a device 700 that is suitable for implementing embodiments of the present disclosure. The device 700 may be provided to implement the first device or the second device, for example the first device 110 or the second device 120 as shown in Fig. 1. As shown, the device 700 includes one or more processors 710, one or more memories 720 coupled to the processor 710, and one or more communication modules 740 (such as, transmitters and/or receivers) coupled to the processor 710.

The communication module 740 is for bidirectional communications. The communication module 740 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

The processor 710 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 700 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.

The memory 720 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) 724, 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) 722 and other volatile memories that will not last in the power-down duration.

A computer program 730 includes computer executable instructions that are executed by the associated processor 710. The program 730 may be stored in the ROM 724. The processor 710 may perform any suitable actions and processing by loading the program 730 into the RAM 722.

The embodiments of the present disclosure may be implemented by means of the program 730 so that the device 700 may perform any process of the disclosure as discussed with reference to Figs. 3 and 5-6. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

In some embodiments, the program 730 may be tangibly contained in a computer readable medium which may be included in the device 700 (such as in the memory 720) or other storage devices that are accessible by the device 700. The device 700 may load the program 730 from the computer readable medium to the RAM 722 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. 8 shows an example of the computer readable medium 800 in form of CD or DVD. The computer readable medium has the program 730 stored thereon.

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.

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

methods

500 and 600 as described above with reference to Figs. 5 and 6. 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.

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.

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.

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.

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.

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.

Claims

A first device comprising:

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code configured to, with the at least one processor, cause the first device to:

in accordance with a determination that a traffic is to be transmitted, transmit the traffic to a second device on a first resource configured for initial transmission of the traffic;

start a timer configured for retransmission of the traffic;

in accordance with a determination that the timer expires, activate a second resource configured for the retransmission; and

retransmit the traffic on the activated second resource.
The first device of claim 1, wherein the first device is caused to activate the second resource by:

in accordance with a determination that the initial transmission in the first resource is cancelled due to the transmission of a higher priority traffic in a resource overlapping with the first resource, activating the second resource.
The first device of claim 1, wherein the first device is further caused to:

receive, from the second device, a first configuration indicating the first resource and a second configuration indicating the second resource.
The first device of claim 3, where the second configuration comprises at least one of the following:

an offset of the second resource with respect to the first resource;

an offset of the second resource with respect to a time reference system frame number; or

a configured grant index of the second resource.
The first device of claim 3, wherein the second resource comprises a set of resources, and the offset comprises a set of offset values for the set of resources.
The first device of claim 3, wherein the first device is caused to receive the first and second configurations by:

receiving the first and second configurations in a higher layer signaling, or

receiving the first and second configurations in separate higher layer signaling.
The first device of claim 1, wherein the first device is caused to retransmit the traffic by:

determining an identifier of a hybrid automatic repeat request process associated with the initial transmission; and

performing the retransmission with the identifier of the hybrid automatic repeat request process.
The first device of claim 7, wherein the first device is caused to determine the identifier by:

determining the identifier at least based on a length of the timer, a period of the first resource, and an offset of the second resource with respect to the first resource.
The first device of claim 1, wherein the first device is further caused to:

receive a hybrid automatic repeat request feedback for the retransmission from the second device; and

in accordance with a determination that the hybrid automatic repeat request feedback indicates that the traffic is received by the second device successfully, deactivate the second resource.
The first device of claim 1, wherein the first device is further caused to:

in accordance with a determination that a timer configured for a hybrid automatic repeat request process associated with the initial transmission expires, deactivate the second resource.
The first device of claim 1, wherein the first device is a terminal device, and the second device is a network device.
A second device comprising:

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code configured to, with the at least one processor, cause the second device to:

receive, from a first device, a traffic on a first resource configured for initial transmission of the traffic;

in accordance with a determination that a hybrid automatic repeat request feedback for the initial transmission or a grant for retransmission of the traffic is not transmitted successfully, determine an activated second resource configured for retransmission of the traffic; and

receive, from the first device, the traffic retransmitted on the activated second resource.
The second device of claim 12, wherein the second device is further caused to:

transmit, to the first device, a first configuration indicating the first resource and a second configuration indicating the second resource.
The second device of claim 13, wherein the second configuration comprises at least one of the following:

an offset of the second resource with respect to the first resource;

an offset of the second resource with respect to a time reference system frame number; or

a configured grant index of the second resource.
The second device of claim 13, wherein the second resource comprises a set of resources, and the offset comprises a set of offset values for the set of resources.
The second device of claim 13, wherein the second device is caused to transmit the first and second configurations by:

transmitting the first and second configurations in a higher layer signaling, or

transmitting the first and second configurations in separate higher layer signaling.
The second device of claim 12, wherein the second device is further caused to:

in accordance with a determination that the hybrid automatic repeat request feedback for the initial transmission or the grant for the retransmission is transmitted successfully, schedule the second resource for other transmission than the retransmission.
The second device of claim 12, wherein the first device is a terminal device, and the second device is a network device.
A method of communication, comprising:

in accordance with a determination that a traffic is to be transmitted, transmitting, at a first device, the traffic to a second device on a first resource configured for initial transmission of the traffic;

starting a timer configured for retransmission of the traffic;

in accordance with a determination that the timer expires, activating a second resource configured for the retransmission; and

retransmitting the traffic on the activated second resource.
The method of claim 19, wherein activating the second resource comprises:

in accordance with a determination that the initial transmission in the first resource is cancelled due to the transmission of a higher priority traffic in a resource overlapping with the first resource, activating the second resource.
The method of claim 19, further comprising:

receiving, from the second device, a first configuration indicating the first resource and a second configuration indicating the second resource.
The method of claim 21, wherein the second configuration comprises at least one of the following:

an offset of the second resource with respect to the first resource;

an offset of the second resource with respect to a time reference system frame number; or

a configured grant index of the second resource.
The method of claim 21, wherein the second resource comprises a set of resources, and the offset comprises a set of offset values for the set of resources.
The method of claim 21, wherein receiving the first and second configurations comprises:

receiving the first and second configurations in a higher layer signaling, or

receiving the first and second configurations in separate higher layer signaling.
The method of claim 19, wherein retransmitting the traffic comprises:

determining an identifier of a hybrid automatic repeat request process associated with the initial transmission; and

performing the retransmission with the identifier of the hybrid automatic repeat request process.
The method of claim 25, wherein determining the identifier comprises:

determining the identifier at least based on a length of the timer, a period of the first resource, and an offset of the second resource with respect to the first resource.
The method of claim 19, further comprising:

receiving a hybrid automatic repeat request feedback for the retransmission from the second device; and

in accordance with a determination that the hybrid automatic repeat request feedback indicates that the traffic is received by the second device successfully, deactivating the second resource.
The method of claim 19, further comprising:

in accordance with a determination that a timer configured for a hybrid automatic repeat request process associated with the initial transmission expires, deactivating the second resource.
The method of claim 19, wherein the first device is a terminal device, and the second device is a network device.
A method of communication, comprising:

receiving, at a second device and from a first device, a traffic on a first resource configured for initial transmission of the traffic;

in accordance with a determination that a hybrid automatic repeat request feedback for the initial transmission or a grant for retransmission of the traffic is not transmitted successfully, determining an activated second resource configured for retransmission of the traffic; and

receiving, from the first device, the traffic retransmitted on the activated second resource.
The method of claim 30, further comprising:

transmitting, to the first device, a first configuration indicating the first resource and a second configuration indicating the second resource.
The method of claim 31, wherein the second configuration comprises at least one of the following:

an offset of the second resource with respect to the first resource;

an offset of the second resource with respect to a time reference system frame number; or

a configured grant index of the second resource.
The method of claim 31, wherein the second resource comprises a set of resources, and the offset comprises a set of offset values for the set of resources.
The method of claim 31, wherein transmitting the first and second configurations comprises:

transmitting the first and second configurations in a higher layer signaling, or

transmitting the first and second configurations in separate higher layer signaling.
The method of claim 30, further comprising:

in accordance with a determination that the hybrid automatic repeat request feedback for the initial transmission is transmitted successfully, scheduling the second resource for other transmission than the retransmission.
The method of claim 30, wherein the first device is a terminal device, and the second device is a network device.
An apparatus of communication, comprising:

means for in accordance with a determination that a traffic is to be transmitted, transmitting, at a first device, the traffic to a second device on a first resource configured for initial transmission of the traffic;

means for starting a timer configured for retransmission of the traffic;

means for in accordance with a determination that the timer expires, activating a second resource configured for the retransmission; and

means for retransmitting the traffic on the activated second resource.
An apparatus of communication, comprising:

means for receiving, at a second device and from a first device, a traffic on a first resource configured for initial transmission of the traffic;

means for in accordance with a determination that a hybrid automatic repeat request feedback for the initial transmission or a grant for retransmission of the traffic is not transmitted successfully, determining an activated second resource configured for retransmission of the traffic; and

means for receiving, from the first device, the traffic retransmitted on the activated second resource.
A non-transitory computer readable medium comprising program instructions for causing an apparatus to perform the method according to any of claims 19 to 29.
A non-transitory computer readable medium comprising program instructions for causing an apparatus to perform the method according to any of claims 30 to 36.