WO2024065855A1

WO2024065855A1 - Fractional rate harq feedback

Info

Publication number: WO2024065855A1
Application number: PCT/CN2022/123660
Authority: WO
Inventors: Tzu-Chung Hsieh; Gilsoo LEE; Jing Yuan Sun; Ping Yuan; Pingping Wen
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2022-09-30
Filing date: 2022-09-30
Publication date: 2024-04-04

Abstract

Example embodiments of the present disclosure relate to HARQ feedback at a fractional rate. In an example method, a terminal device receives, from a network device, a hybrid automatic repeat request (HARQ) feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and the network device. The terminal device transmits the HARQ feedback to the network device or receives HARQ feedback from the network device based on the fractional feedback rate. In this way, the configurable HARQ feedback rate enables the network device to receive acknowledgement of control messages and perform link adaptation while improving user throughput in NTN deployment scenarios. Moreover, reduced ACK/NACK transmissions also lead to UE power saving, which is critical for IoT devices.

Description

FRACTIONAL RATE HARQ FEEDBACK

FIELD

Example embodiments of the present disclosure generally relate to the field of telecommunication, and in particular, to methods, devices, and a computer-readable medium for communication.

BACKGROUND

HARQ (Hybrid Automatic Repeat reQuest) is implemented in the MAC (Medium Access Control) protocol by using a retransmission system of 5G NR (New Radio) . Once DL (Downlink) data is transmitted to a terminal device (also referred to as “UE” or “user equipment” ) from a network device (also referred to as “eNB” , “eNodeB” , “gNB” or “gNodeB” ) , the HARQ feedback is sent from the terminal device to a network device after each received transport block (TB) . If the received data decoding incurs an error, the terminal device buffers the received data and requests a retransmission. The network device also needs to buffer the transmitted data until an acknowledgement is received from the terminal device. In doing so, when a NACK (Negative Acknowledgement) is received, the network device can retransmit the data to the terminal device. To correct the erroneous packets, the terminal device receives the retransmitted data and combines the retransmitted data with the buffered data (also referred to as “soft combination” ) for another decoding attempt. Therefore, the HARQ mechanism is based on a feedback on success or failure of the downlink transmission.

SUMMARY

In general, example embodiments of the present disclosure provide a solution for HARQ feedback at a fractional rate.

In a first aspect, there is provided a terminal device. The terminal device comprises a processor and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device to: receive, from a network device, a HARQ feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and the network device; and transmit HARQ feedback to the network device or receive HARQ feedback from the network device based on the fractional feedback rate.

In a second aspect, there is provided a network device. The network device comprises a processor and at least one memory storing instructions that, when executed by the at least one processor, cause the first network device to: transmit, to a terminal device, a HARQ feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and the network device; and receive HARQ feedback from the terminal device or transmit HARQ feedback to the terminal device based on the fractional feedback rate.

In a third aspect, there is provided a method implemented in a terminal device according to the first aspect. The method comprises: receiving, at a terminal device from a network device, a HARQ feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and the network device; and transmitting the HARQ feedback to the network device or receive HARQ feedback from the network device based on the fractional feedback rate.

In a fourth aspect, there is provided a method implemented at a network device according to the second aspect. The method comprises: transmitting, to a terminal device, a HARQ feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and a network device; and receiving HARQ feedback from the terminal device or transmit HARQ feedback to the terminal device based on the fractional feedback rate.

In a fifth aspect, there is provided an apparatus implemented in a terminal device according to the first aspect. The apparatus comprises: means for receiving, at a terminal device from a network device, a HARQ feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and the network device; and means for transmitting the HARQ feedback to the network device or receive HARQ feedback from the network device based on the fractional feedback rate.

In a sixth aspect, there is provided an apparatus implemented in a network device according to the second aspect. The apparatus comprises: means for transmitting, to a terminal device, a HARQ feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and a network device; and means for receiving HARQ feedback from the terminal device or transmit HARQ feedback to the terminal device based on the fractional feedback rate.

In an seventh aspect, there is provided a non-transitory computer-readable storage medium having instructions stored thereon. The instructions, when executed on at least one processor, cause the least one processor to perform the method of any of the third or fourth aspects.

In an eighth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to: receive, from a network device, a HARQ feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and the network device; and transmit HARQ feedback to the network device or receive HARQ feedback from the network device based on the fractional feedback rate.

In an ninth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to: transmit, to a terminal device, a HARQ feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and the network device; and receive HARQ feedback from the terminal device or transmit HARQ feedback to the terminal device based on the fractional feedback rate.

In a tenth aspect, there is provided a terminal device according to the first aspect. The terminal device comprises: receiving circuitry configured to receive, from a network device, a HARQ feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and the network device; and transmitting circuitry configured to transmit the HARQ feedback to the network device or receive HARQ feedback from the network device based on the fractional feedback rate.

In a eleventh aspect, there is provided a network device according to the second aspect. The network device comprises: transmitting circuitry configured to transmit, to a terminal device, a HARQ feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and a network device; and receiving circuitry configured to receive HARQ feedback from the terminal device or transmit HARQ feedback to the terminal device based on the fractional feedback rate.

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, in which:

FIG. 1 illustrates an example of a network environment in which some example embodiments of the present disclosure may be implemented;

FIG. 2 illustrates a signaling chart illustrating a communication process in accordance with some example embodiments of the present disclosure;

FIG. 3 illustrates another signaling chart illustrating another communication process in accordance with some example embodiments of the present disclosure;

FIG. 4 illustrates an example HARQ feedback configuration in accordance with some example embodiments of the present disclosure;

FIG. 5A illustrates another example HARQ feedback configuration in accordance with some example embodiments of the present disclosure;

FIG. 5B illustrates another example HARQ feedback configuration in accordance with some example embodiments of the present disclosure;

FIG. 6 illustrates a schematic chart illustrating timeline of HARQ feedback configuration in accordance with some example embodiments of the present disclosure;

FIG. 7 illustrates a flowchart of an example method implemented at a terminal device in accordance with some embodiments of the present disclosure;

FIG. 8 illustrates another flowchart of an example method implemented at a network device in accordance with some embodiments of the present disclosure; and

FIG. 9 illustrates a simplified block diagram of a device that is suitable for implementing some example embodiments of the present disclosure; and

FIG. 10 illustrates a block diagram of an example of a computer-readable medium in accordance with some example embodiments of the present disclosure.

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

Through this document, the terms defined below may be referenced.

ACK acknowledge

ARQ Automatic Repeat reQuest

BLER Block Error Rate

CRC cyclic redundancy check

DCI downlink control information

DL downlink

HARQ Hybrid Automatic Repeat reQuest

GEO geosynchronous equatorial orbit

gNB gNodeB

MAC medium access control

MAC CE MAC Control Element

MCS Modulation and Coding Scheme

NACK negative acknowledge

NTN non-terrestrial network

NR New Radio

UE user equipment

LEO low Earth orbit

PDCCH physical downlink control channel

PDSCH physical downlink shared channel

RTT round trip time

RNTI Radio Network Temporary Identifier

SAW stop and wait

TB Transport Block

TTI Transmission Time Interval

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 (for example, 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 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 fourth generation (4G) , 4.5G, the future fifth generation (5G) 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.

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 (for example, remote surgery) , an industrial device and applications (for example, 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. In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.

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 (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 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 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 by providing the user equipment with software configured to cause the user equipment to perform from the point of view of these functions/nodes.

As mentioned above, HARQ is implemented in the MAC protocol by using a retransmission system of 5G NR. Once DL data is transmitted to a terminal device from a network device, the HARQ feedback is sent from the terminal device to a network device after each received TB. If the received data decoding incurs an error, the terminal device buffers the received data and requests a retransmission. The network device also needs to buffer the transmitted data until an acknowledgement is received from the terminal device. In doing so, when a NACK is received, the network device can retransmit the data to the terminal device. To correct the erroneous packets, the terminal device receives the retransmitted data and combines the retransmitted data with the buffered data for another decoding attempt. Therefore, the HARQ mechanism is based on a feedback on success or failure of the downlink transmission.

HARQ is also a stop and wait (SAW) ARQ protocol implemented in multiple parallel processes. The HARQ protocol will use the receiver’s ACK/NACK feedback to ensure reliable DL transmission in each parallel process. Multiple processes are identified by a HARQ process number ‘harq_process’ in the DCI (downlink control information) carried by PDCCH.

In addition, a large RTT (round trip time) can incur HARQ stalling that prohibits the transmissions of other processes. In particular, NTN (non-terrestrial network) scenarios have the maximum round trip delay such as 541.46 ms for GEO (geosynchronous equatorial orbit) and 25.77 ms for LEO (low Earth orbit) at 600 km altitude. Since the RTT is extraordinarily large in NTN, one RTT may span many TTIs (Transmission Time Interval) , thus causing a serious HARQ stalling.

WID of Rel-18 [RP-212729] describes the topic on disabling HARQ feedback:

IoT over NTN in Rel-18 considers that the small number of HARQ processes is used for NB-IoT. For NB-IoT devices with only one HARQ process, disabling HARQ feedback will prevent the eNB from knowing if a control message has been received by the UE.For IoT devices with two or more HARQ processes, the network may configure at least one process with feedback enabled to support acknowledgement of control messages and reliable data transmissions. However, for NB-IoT devices with only one HARQ process, the network will not get acknowledgement of signaling messages if HARQ feedback is disabled. For those devices, switching between feedback enabled and feedback disabled may be considered in order to provide throughput and power saving benefits for the UE and ensure reliable delivery of control messages.

IoT UE may operate in half-duplex mode. For half-duplex UE, more DL scheduling opportunity is created without HARQ feedback in the UL, which may increase DL throughput.

Table 1. DL throughput (in kbps) comparison when HARQ feedback is enabled and disabled [R1-2207291]

Throughput gain from disabling HARQ feedback is studied in [R1-2207291] . When feedback is disabled. Table 1 shows a throughput gain in GEO scenarios mainly due to elimination of HARQ stalling and also a throughput gain in LEO 600 km scenarios due to more scheduling opportunities from the omitted ACK/NACK transmission. Thus, disabling HARQ feedback for DL transmission can improve the downlink throughput.

Finally, in RAN1#109-e the following RAN1 agreements are made recently to enhance HARQ process for IoT NTN.

According to the agreements above, it is required to enhance the HARQ procedure by adopting a new disabling HARQ feedback scheme.

In NTNs, the long propagation time between the terminal device and the network device through satellite can easily cause HARQ stalling which becomes the bottleneck of achievable user throughput. This is especially true for low complexity IoT (Internet of Things) devices since their smaller soft buffer for data reception limits the number of HARQ processes. Therefore, disabling HARQ feedback --so that the network device does not need to wait for ACK/NACK before starting a new packet transmission --has been adopted in 3GPP (The Third Generation Partnership Project) Rel-17 (Release 17) NR (New Radio) and is under consideration for Rel-18 LTE (Long Term Evolution) eMTC (enhanced Machine Type Communication) and NB-IoT (Narrow Band –Internet of Things) .

On the other hand, MAC CE (Control Element) messages sent by the network device to the terminal device (e.g., DRX (Discontinuous Reception) Command, TAC (Timing Advance Command) , etc. ) require an HARQ-ACK bit to confirm their reception before those commands can take effect. RRC (Radio Resource Control) signaling messages also require HARQ-ACK to confirm their reception. Disabling HARQ feedback on a HARQ process therefore inhibits MAC CE and RRC signaling over that process. For NB-IoT UE with only one HARQ process, the system would not be able to operate if HARQ feedback is disabled.

In addition, with HARQ feedback disabled, the ACK/NACK bit used by the network device as an indicator for MCS (Modulation and Coding Scheme) and repetition adjustment is no longer available. For effective link adaptation, network can configure some of the UE’s HARQ processes to send feedback and use the ACK/NACK from those HARQ processes to adapt its transmission scheme (i.e., MCS, repetition) to the UE’s channel condition. However, NB-IoT devices may only support 1 HARQ process. In that case, disabling HARQ feedback will make the network unable to perform timely link adaptation for DL data transmission. This can lead to either resource waste when MCS/repetition is overly conservative or continuous packet errors when MCS/repetition is insufficient. The impact of the latter is far more serious since repeated decoding errors will happen when there is no soft combining in the HARQ process. Network may not even be aware of the UE becoming out of coverage or being blocked by terrain/buildings until radio link failure is triggered. In general, link adaptation is more critical when channel condition is worse.

For these problems, one solution is dynamically switching feedback on and off by additional DCI indication, but this would require changing DCI formats and adding UE’s complexity for DCI detection. Moreover, relying on DCI for enabling/disabling HARQ feedback would run into complication when a single DCI is used to schedule multiple PDSCH (Physical Downlink Shared Channel) transmissions in the cases of semi-persistent scheduling (SPS) and multiple-TB scheduling.

In this application, a solution is introduced to simultaneously mitigate HARQ stalling and support control message acknowledgement and link adaptation without the aforementioned complications. This application applies to the scenarios (e.g., in NTN when there exists a long propagation delay) where HARQ stalling becomes a bottleneck of achievable user throughput and/or when a single DCI is used to schedule multiple TBs (e.g., in SPS or multi-TB scheduling) .

Instead of completely enabling or disabling HARQ feedback, we propose sending HARQ feedback (ACK/NACK) at a fractional rate. A fractional feedback rate 1/N is one ACK/NACK bit sent by the receiver to the transmitter for the N TBs scheduled by a DCI. (Note: Legacy HARQ has feedback rate 1 since an ACK/NACK bit is sent for every data TB scheduled. Whereas when HARQ feedback is disabled, feedback rate is 0 since no ACK/NACK feedback is sent. )

FIG. 1 illustrates an example communication system 100 in which some embodiments of the present disclosure can be implemented. The communication system 100, which is a part of a communication network, includes a network device 110 and a terminal device 120.

The network device 110 can provide services to the terminal device 120, and the network device 110 and the terminal device 120 may communicate data and control information with each other. In some embodiments, the network device 110 and the terminal device 120 may communicate with direct links/channels.

In the system 100, a link from the network devices 110 to the terminal device 120 is referred to as a downlink (DL) , while a link from the terminal device 120 to the network devices 110 is referred to as an uplink (UL) . In downlink, the network device 110 is a transmitting (TX) device (or a transmitter) and the terminal device 120 is a receiving (RX) device (or a receiver) . In uplink, the terminal device 120 is a transmitting (TX) device (or a transmitter) and the network device 110 is a RX device (or a receiver) . It is to be understood that the network device 110 may provide one or more serving cells. As illustrated in FIG. 1, the network device 110 provides one serving cell 102, and the terminal device 120 camps on the serving cell 102. In some embodiments, the network device 110 can provide multiple serving cells. It is to be understood that the number of serving cell (s) shown in FIG. 1 is for illustrative purposes only without suggesting any limitation.

The communications in the communication system 100 may conform to any suitable standards including, but not limited to, Long Term Evolution (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) , 5.5G, 5G-Advanced networks, or the sixth generation (6G) communication protocols.

It is to be understood that the number of devices and their connection relationships and types shown in FIG. 1 are for illustrative purposes only without suggesting any limitation. The communication system 100 may comprise any suitable number of devices adapted for implementing embodiments of the present disclosure.

FIG. 2 illustrates a signaling chart illustrating a communication process 200 in accordance with some example embodiments of the present disclosure. Only for the purpose of discussion, the communication process 200 will be described with reference to FIG. 1. The communication process 200 may involve the terminal device 120 and the network device 110.

In some example embodiments, the network device 110 transmits to the terminal device 120 a HARQ feedback configuration 201 indicating a fractional feedback rate for HARQ feedback between the terminal device 120 and the network device 110. At the same time, on the other side of communication, the terminal device 120 receives, from the network device 110, the HARQ feedback configuration 201 indicating the fractional feedback rate for HARQ feedback between the terminal device 120 and the network device 110.

For example, the network device 110 may transmit 220 to the terminal device 120 the HARQ feedback configuration 201 (for example, by MAC CE and/or RRC signaling) indicating the fractional feedback rate for HARQ feedback between the terminal device 120 and the network device 110, as illustrated in FIG. 2. On the other side of communication, the terminal device 120 receives 222 the HARQ feedback configuration 201 from the network device 110. With the received HARQ feedback configuration 201, the terminal device 120 can be configured with such HARQ feedback configuration 201.

Additionally, in some example embodiments, the terminal device 120 transmits the HARQ feedback to the network device 110 or receives HARQ feedback from the network device 110 based on the fractional feedback rate. On the other side of communication, the network device 110 receives the HARQ feedback from the terminal device 120 or transmits HARQ feedback to the terminal device 120 based on the fractional feedback rate.

For example, after being configured with such HARQ feedback configuration 201, the terminal device 120 may transmit the HARQ feedback to the network device 110 based on the fractional feedback rate. Alternatively, the terminal device 120 may receive HARQ feedback from the network device 110 based on the fractional feedback rate. On the other side of communication, the network device 110 may receive the HARQ feedback from the terminal device 120 based on the fractional feedback rate, as illustrated in FIG. 2. Alternatively, the network device 110 may transmit HARQ feedback to the terminal device 120 based on the fractional feedback rate.

In addition, in some example embodiments, the network device 110 further determines the HARQ feedback configuration based on at least one of the following: required latency for reliable data transfer; downlink channel quality report (DCQR) from the terminal device 120; a propagation loss change rate; or an uplink (UL) traffic load.

For example, the network device 110 may determine 210 the HARQ feedback configuration 201 from the following information:

●Required latency for reliable data transfer (e.g., MAC CE or RRC messages) .

●Downlink Channel Quality Report (DCQR) from the terminal device 120 can be used by the network device 110 to set the feedback rate. A higher feedback rate may be desired for a lower channel quality to facilitate quicker link adaptation.

●Propagation loss change rate which may depend on the location and elevation angle of the terminal device 120 with respect to the satellite where the network device 110 resides.

●UL traffic load with which HARQ feedback would share resource.

FIG. 3 illustrates another signaling chart illustrating another communication process 300 in accordance with some example embodiments of the present disclosure. Only for the purpose of discussion, the communication process 300 will be described with reference to FIGs. 1 and 2. The communication process 300 may involve the terminal device 120 and the network device 110. For the same or like operation (s) as in communication process 200, description of communication process 200 can be referenced, so details will be omitted.

In some example embodiments, the fractional feedback rate is 1/N and N is an integer greater than 1.

In addition or alternatively, in some example embodiments, the terminal device transmits the HARQ feedback by: transmitting a HARQ feedback indication for N TBs scheduled by single DCI. On the other side of communication, the network device 110 receives the HARQ feedback by: receiving a HARQ feedback indication for N TBs scheduled by single DCI.

In addition or alternatively, in some example embodiments, the terminal device 120 transmits the HARQ feedback indication after receiving a K-th TB among the N TBs, and K is an integer equal to or less than N. On the other side of communication, the network device 110 receives the HARQ feedback indication after transmitting a K-th TB among the N TBs, and K is an integer equal to or less than N.

In addition or alternatively, in some example embodiments, the HARQ feedback configuration indicates the fractional feedback rate by indicating a value of K and a value of N.

In addition or alternatively, in some example embodiments, the HARQ feedback indication is indicative of one of the following: decoding status of the K-th TB, or combined decoding status of previous K TBs among the N TBs.

In addition or alternatively, in some example embodiments, the DCI comprises a field indicating an allocated uplink resource for the HARQ feedback indication for the K-th TB without indicating allocated uplink resources for HARQ feedback for other (N-1) TBs.

In addition or alternatively, in some example embodiments, the K-th TB is used to receive at least one of a MAC CE or a RRC message.

In addition or alternatively, in some example embodiments, the network device 110 transmits the HARQ feedback configuration via at least one of an MAC CE or an RRC message. On the other side of communication, the terminal device 120 receives the HARQ feedback configuration via at least one of an MAC CE or an RRC message.

In addition or alternatively, in some example embodiments, the terminal device is in a non-terrestrial network.

In one example, as illustrated in FIG. 3, the communication process 300 is for example a signaling flow of HARQ feedback process at a fractional feedback rate. In one example, the network device 110 configures a fractional feedback rate 1/N for single DCI scheduled multiple TBs (multiple PDSCH transmission) . Specifically, the configuration indicates one ARQ feedback (ACK/NACK) after the reception of the K-th TB (K≤N) for every N TBs received by the terminal device 120. The ACK/NACK may indicate decoding status (success/failure) of the K-th TB (e.g., the most recent one) , or the “exclusive OR” or the “exclusive AND” of the previous K TBs. The configuration can be carried by MAC CE or RRC message. The configuration takes effect after the network device 110 receives an HARQ-ACK at a certain system time.

In another example, the network device 110 can configure HARQ feedback rate with parameters {K, N} via RRC messages or MAC CE. With this configuration, when multiple TBs are scheduled by a DCI, as in the case of SPS and multi-TB scheduling, the terminal device 120 is supposed to send a HARQ feedback (ACK/NACK) after the reception of the K-th TB (where K≤N) in every N TBs as illustrated in FIGs. 3-5. Legacy HARQ feedback is represented with the configuration {K=1, N=1} , where an ACK/NACK should be sent for every TB received. While the configuration {K=0, N=0} can be used to completely disable HARQ feedback. RRC signaling is a means of configuration for semi-static, long-term basis, while MAC CE provides a means of configuration that can be adaptable and dynamic.

The configuration may also indicate how the ACK/NACK bit should be computed. It can be, for example, the decoding status of the K-th TB, or the “exclusive OR” or the “exclusive AND” of the previous K TBs. The network device 110 can use the feedback not only to learn the reception status of the transmitted data, but also to adjust the MCS and repetition for future data transmission.

Specifically, as illustrated in FIG. 3, the network device 110 transmits 220 the HARQ feedback configuration 201 (specifically, for example, HARQ feedback rate configuration) to the terminal device 120. On the other side of communication, the terminal device 120 receives 222 the HARQ feedback configuration 201 from the network device 110. These operations are the same as those in communication process 200 as illustrated in FIG. 2, description of communication process 200 can be referenced, so details will be omitted.

With the received HARQ feedback configuration 201, the terminal device 120 can be configured with such HARQ feedback configuration 201, as described above with reference to FIG. 2. After being configured with such HARQ feedback configuration 201, the terminal device 120 may transmits the HARQ reporting (i.e., HARQ feedback) at the fractional rate 1/N to the network device 110 based on the HARQ feedback configuration 201. For example, the terminal device 120 transmits 230 HARQ feedback (i.e., ACK/NACK) 202 to the network device 110. On the other side of communication, the network device 110 receives 232 the HARQ feedback (i.e., ACK/NACK) 202 from the terminal device 120. These operations are the same as those in communication process 200 as illustrated in FIG. 2, description of communication process 200 can be referenced, so details will be omitted.

Upon receipt of the HARQ feedback (i.e., ACK/NACK) 302 from the terminal device 120, the network device 110 can activate the HARQ feedback configuration 201, as illustrated in FIG. 3.

Upon activation of the HARQ feedback configuration 201, the network device 110 continues to transmit 318 DCI for multiple (specifically, “n” ) TBs on the PDCCH (physical downlink control Channel) . On the other side of communication, the terminal device 120 receives 320 the DCI for multiple TBs on the PDCCH.

Then, the network device 110 transmits 322 a TB with index “1” on the PDSCH to the terminal device 120. On the other side of communication, the terminal device 120 receives 324 the TB with index “1” on the PDSCH from the network device 110. Then, the network device 110 transmits 326 a TB with index “2” on the PDSCH to the terminal device 120. On the other side of communication, the terminal device 120 receives 328 the TB with index “2” on the PDSCH from the network device 110. Such a flow goes on and on in this way.

Then, the network device 110 transmits 330 a TB with index “k” on the PDSCH to the terminal device 120. On the other side of communication, the terminal device 120 receives 332 the TB with index “k” on the PDSCH from the network device 110.

As described above, K is a parameter comprised in the HARQ feedback configuration 201 which has been configured to the terminal device 120 by the network device 110. Therefore, upon receipt of the TB with index “k” , the terminal device 120 transmits 334 a HARQ feedback (ACK/NACK) 303 to the network device 110. On the other side of communication, the network device 110 receives 336 the HARQ feedback (ACK/NACK) 303 from the terminal device 120.

The network device 110 continues to transmit 338 a TB with index “K+1” on the PDSCH to the terminal device 120. On the other side of communication, the terminal device 120 receives 340 the TB with index “K+1” on the PDSCH from the network device 110. Such a flow goes on and on in this way.

Then, the network device 110 transmits 350 a TB with index “n” on the PDSCH to the terminal device 120. On the other side of communication, the terminal device 120 receives 352 the TB with index “n” on the PDSCH from the network device 110. This round of transmission of N TBs terminates at this point; at the same time, the next round of transmission of N TBs begins at this point.

As illustrated in FIG. 3, the network device 110 transmits 354 a TB with index “N+1” on the PDSCH to the terminal device 120. On the other side of communication, the terminal device 120 receives 356 the TB with index “N+1” on the PDSCH from the network device 110. Then, the network device 110 transmits 358 a TB with index “N+2” on the PDSCH to the terminal device 120. On the other side of communication, the terminal device 120 receives 360 the TB with index “N+2” on the PDSCH from the network device 110. Such a flow goes on and on in this way.

Then, the network device 110 transmits 370 a TB with index “N+K” on the PDSCH to the terminal device 120. On the other side of communication, the terminal device 120 receives 372 the TB with index “N+K” on the PDSCH from the network device 110.

As described above, K is a parameter comprised in the HARQ feedback configuration 201 which has been configured to the terminal device 120. Therefore, upon receipt of the TB with index “N+K” , the terminal device 120 transmits 374 a HARQ feedback (ACK/NACK) 304 to the network device 110. On the other side of communication, the network device 110 receives 376 the HARQ feedback (ACK/NACK) 304 from the terminal device 120.

The network device 110 continues to transmit 378 a TB with index “N+K+1” on the PDSCH to the terminal device 120. On the other side of communication, the terminal device 120 receives 380 the TB with index “N+K+1” on the PDSCH from the network device 110. Such a flow goes on and on in this way.

Then, the network device 110 transmits 390 a TB with index “2n” on the PDSCH to the terminal device 120. On the other side of communication, the terminal device 120 receives 392 the TB with index “2n” on the PDSCH from the network device 110. This round of transmission of N TBs terminates at this point; at the same time, the next round of transmission of N TBs begins at this point. Such a flow goes on and on in this way.

A fractional feedback rate being 1/N for the HARQ feedback configuration is described in detail in the above with reference to FIG. 3. A more general fractional feedback rate being M/N is also considered, where M<N, i.e., for every N TBs transmitted there would be M HARQ feedback bits sent back corresponding to the K _i-th TBs, where i is one of {1, 2, …, M} . For example with a fractional feedback rate of 3/8 (M=3, N=8) , and K ₁=1, K ₂=2, K ₃=4, HARQ feedback bits will be sent after the terminal device 120 receives the 1st, 2nd, and 4th TBs for every 8 TBs. This scenario will be described in detail with reference to FIG. 4.

FIG. 4 illustrates an example HARQ feedback configuration (hereafter referred to as “the first HARQ feedback configuration” ) in accordance with some example embodiments of the present disclosure. Only for the purpose of discussion, the first HARQ feedback configuration will be described with reference to FIGs. 1 and 3. The first HARQ feedback configuration may involve the terminal device 120 and the network device 110.

In some example embodiments, the fractional feedback rate is M/N and N is an integer greater than 1, M is an integer less than N but no less than 1. Specifically, when M=1, the fractional feedback rate is 1/N, which is the case as illustrated in FIG. 3.

In addition or alternatively, in some example embodiments, the terminal device transmits the HARQ feedback by: transmitting M HARQ feedback indication for N TBs scheduled by single DCI. On the other side of communication, the network device 110 receives the HARQ feedback by: receiving M HARQ feedback indication for N TBs scheduled by single DCI.

In addition or alternatively, in some example embodiments, the terminal device 120 transmits the HARQ feedback indication after receiving a K _i-th TB among the N TBs, and any of K _i is an integer equal to or less than N, where i is one of {1, 2, …, M} . On the other side of communication, the network device 110 receives the HARQ feedback indication after transmitting a K _i-th TB among the N TBs, and K _i is an integer equal to or less than N, where i is one of {1, 2, …, M} .

In addition or alternatively, in some example embodiments, the HARQ feedback configuration indicates the fractional feedback rate by indicating a value of M and a value of N.

In addition or alternatively, in some example embodiments, the HARQ feedback indication is indicative of one of the following: decoding status of the K _i-th TB, or combined decoding status of previous K _i TBs among the N TBs.

In addition or alternatively, in some example embodiments, the DCI comprises a field indicating an allocated uplink resource for the HARQ feedback indication for the K _i-th TB, respectively, without indicating allocated uplink resources for HARQ feedback for other (N-M) TBs.

In addition or alternatively, in some example embodiments, the K _i-th TB is used to receive at least one of a MAC CE or a RRC message.

In addition or alternatively, in some example embodiments, the terminal device 120 is in a non-terrestrial network.

In one example shown in FIG. 4, a HARQ feedback configuration with M=3, N=8, K ₁=1, K ₂=2, K ₃=4 in full duplex FDD is illustrated. In this case, the fractional feedback rate is computed as M/N=3/8, which means a HARQ feedback (i.e., ACK/NACK or simply “A/N” ) will be sent by the terminal device 120 after receiving the 1st (corresponding to K ₁=1) , 2nd (corresponding to K ₂=2) , and 4th (corresponding to K _M=4, where M=3) TBs, respectively, for every 8 (corresponding to N=8) TBs. Processing associated with each the K _i-th (i is one of {1, 2, …, M} ) TB is similar to that associated with the K-th TB as illustrated in FIG. 3 when M=1.

Specifically, the terminal device 120 may be in a non-terrestrial network. The network device 110 may transmit the above HARQ feedback configuration (i.e., M=3, N=8, K ₁=1, K ₂=2, K ₃=4) via at least one of an MAC CE or an RRC message. On the other side of communication, the terminal device 120 may receive the above HARQ feedback configuration via at least one of an MAC CE or an RRC message.

In addition or alternatively, the terminal device 120 transmits a first HARQ feedback indication (for example, either an ACK or a NACK bit) after receiving the 1st (corresponding to K ₁=1) TB among the 8 TBs, transmits a second HARQ feedback indication (for example, either an ACK or a NACK bit) after receiving the 2nd (corresponding to K ₂=2) TB among the 8 TBs, and transmits a third HARQ feedback indication (for example, either an ACK or a NACK bit) after receiving the 4th (corresponding to K _M=4 where M=3) TB among the 8 TBs. On the other side of communication, the network device 110 receives the first HARQ feedback indication after transmitting the 1st TB among the 8 TBs, receives the second HARQ feedback indication after transmitting the 2nd TB among the 8 TBs, and receives the third HARQ feedback indication after transmitting the 4th TB among the 8 TBs, .

In another example, each of the M HARQ feedback indications may be indicative of one of the following: decoding status of the K _i-th TB, or combined decoding status of previous K _i TBs among the N TBs. Specifically, the first HARQ feedback indication may be indicative of the decoding status of the 1st TB, the second HARQ feedback indication may be indicative of a combined decoding status of the previous 2 TBs (for example, the “exclusive OR” of the previous 2 TBs) , and the third HARQ feedback indication may be indicative of a combined decoding status of the previous 2 TBs (for example, the “exclusive AND” of the previous 4 TBs) .

Alternatively, the combined decoding status of previous L TBs can be used to determine the HARQ feedback indication. Here L is an integer and can be configured by the network device 110 or pre-defined and the L TBs can be among the N TBs or the L TBs can be just previous L TBs that may contain some TBs outside of the N TBs. For example, assuming L=5, then, in this case, the first HARQ feedback indication may be indicative of the combined decoding status (for example, “exclusive OR” or “exclusive AND” ) of the previous 5 TBs (including or not including the 1st TB) , the second HARQ feedback indication may be indicative of a combined decoding status of the previous 5 TBs (including or not including the 2nd TB) , and the third HARQ feedback indication may be indicative of a combined decoding status of the previous 5 TBs (including or not including the 4th TB) .

In addition or alternatively, in another example, the terminal device 120 may transmit the three HARQ feedback indications (i.e., the first HARQ feedback indication, the second HARQ feedback indication and the third HARQ feedback indication) for 8 TBs scheduled by single DCI, in order to transmit the HARQ feedback. On the other side of communication, the network device 110 may receive the 3 HARQ feedback indications for 8 TBs scheduled by single DCI.

In addition, in another example, the DCI comprises a field which indicates an allocated uplink resource for the HARQ feedback indication for the 1st (corresponding to K ₁=1) , 2nd (corresponding to K ₂=2) and 4th (corresponding to K _M=4 where M=3) TBs, respectively, without indicating allocated uplink resources for HARQ feedback for other 5 (=N-M, where N=8 and M=3) TBs. This implies that, the network device 110 only allocates uplink resource for the HARQ feedback indication for the 1st, 2nd and 4th TBs, respectively, without indicating allocated uplink resources for HARQ feedback for other 5 TBs corresponding to index 3 and 5-8, respectively.

In addition or alternatively, in another example, the K _i-th TB may be used to receive at least one of a MAC CE or a RRC message. Specifically, the 1st TB in every 8 TBs may be used to receive a MAC CE message, and the 2nd and third TBs in every 8 TBs may be used to receive RRC messages, respectively.

FIG. 5A illustrates another example HARQ feedback configuration (hereafter referred to as “the second HARQ feedback configuration” ) in accordance with some example embodiments of the present disclosure. Only for the purpose of discussion, the second HARQ feedback configuration will be described with reference to FIGs. 1, 3 and 4. The second HARQ feedback configuration may involve the terminal device 120 and the network device 110. The second HARQ feedback configuration can be regarded as the first HARQ feedback configuration when M=1; i.e., HARQ feedback associated with only one TB among N TBs will be reported to the network device 110 by the terminal device 120.

In the example shown in FIG. 5A, a HARQ feedback with configuration K=2, N=4 in full duplex FDD is illustrated. Since there is only one K, it can be inferred that in this case M=1; i.e., only one HARQ feedback will be reported to the network device 110 per every 4 TBs transmitted to the terminal device 120. That’s to say, since K=2 and N=4, the second TB (with index “2” ) in every 4 TBs will have a HARQ feedback to be reported to the network device 110 from the terminal device 120. The fraction rate at which the HARQ feedback is reported is 1/N = 1/4. In other words, only one TB among 4 TBs has a corresponding HARQ feedback which is reported to the network device 110 from the terminal device 120. For example, as illustrated in FIG. 5A, the TB with index “2” in the first 4 TBs (with indices “1” to “4” ) has a corresponding HARQ feedback to be reported to the network device 110, and the TB with index “6” in the second 4 TBs (with indices “5” to “8” ) has a corresponding HARQ feedback to be reported to the network device 110, and so on.

FIG. 5B illustrates another example HARQ feedback configuration (hereafter referred to as “the third HARQ feedback configuration” ) in accordance with some example embodiments of the present disclosure. Only for the purpose of discussion, the third HARQ feedback configuration will be described with reference to FIGs. 1, 3, 4 and 5A. The third HARQ feedback configuration may involve the terminal device 120 and the network device 110.

In the example shown in FIG. 5B, a HARQ feedback with configuration K=2, N=4 in half duplex FDD is illustrated. The example shown in FIG. 5B differs from the example shown in FIG. 5A only in that the working mode of the terminal device 120 is half duplex FDD instead of full duplex FDD. All discussion about the HARQ feedback configuration and HARQ feedback with reference to FIG. 5A applies to the example illustrated in FIG. 5B.

Specifically, in the example illustrated in FIG. 5B, since K=2 and N=4 and there is only one K, it can be inferred that in this case M=1; i.e., only one HARQ feedback will be reported to the network device 110 per every 4 TBs transmitted to the terminal device 120. In other words, since K=2 and N=4, only the second TB (with index “2” ) in every 4 TBs will have a HARQ feedback to be reported to the network device 110 from the terminal device 120. The fraction rate at which the HARQ feedback is reported is also 1/N = 1/4. In other words, only one TB among 4 TBs has a corresponding HARQ feedback which is reported to the network device 110 from the terminal device 120. For example, as illustrated in FIG. 5B, the TB with index “2” in the first 4 TBs (with indices “1” to “4” ) has a corresponding HARQ feedback to be reported to the network device 110, and the TB with index “6” in the second 4 TBs (with indices “5” to “8” ) has a corresponding HARQ feedback to be reported to the network device 110, and so on.

FIG. 6 illustrates a schematic chart 600 illustrating timeline of HARQ feedback configuration in accordance with some example embodiments of the present disclosure. Only for the purpose of discussion, the chart 600 will be described with reference to FIGs. 1-5B. The chart 600 may involve the terminal device 120 and the network device 110.

In some example embodiments, the network device 110 activates the HARQ feedback configuration after receiving, from the terminal device, a HARQ feedback indication that a TB comprising the HARQ feedback configuration is successfully received.

In addition or alternatively, in some example embodiments, the network device 110 determines an activation time of the HARQ feedback configuration based on a time point when the HARQ feedback configuration is transmitted and a delay.

In addition or alternatively, in some example embodiments, the network device 110 determines the delay based on a processing delay of the terminal device, a round trip delay, and a processing delay of the network device.

In addition or alternatively, in some example embodiments, the network device 110 schedules at least one of a MAC CE or RRC message on the K _i-th TB.

In one example, the network device 110 schedules MAC CE and RRC messages on the PDSCH transmissions that have a HARQ feedback. In doing so, the reception of those messages is confirmed and therefore MAC CE commands can be activated.

In another example, the network device 110 only allocates UL resource for HARQ feedback for the PDSCH transmissions that have a HARQ feedback.

In another example, the terminal device 120 only uses the “HARQ-ACK resource” field in the DCI as UL resource indication for HARQ feedback transmission when the PDSCH should have a HARQ feedback according to configuration.

In another example, as illustrated in FIG. 6, for timeline of HARQ feedback configuration, assuming that the HARQ feedback configuration 201 is received by the terminal device 120 from the network device 110 at subframe Nc and the terminal device 120 sends an ACK bit to acknowledge the successful receipt of the configuration message at subframe Nc+Xu (in DL time frame) after a known processing delay Xu subframes. The round-trip delay in NTN in terms of subframe is known as Koffset, which means the ACK bit will be received by the network device 110 at subframe Nc+Xu+Koffset. Allowing the network device 110 a processing delay of Xn subframes, the earliest time the HARQ feedback configuration can take effect is DL subframe Nc+Xu+Koffset+Xn. The processing delays Xu and Xn are pre-determined and understood by both the network device 110 and the terminal device 120. The round-trip delay Koffset is broadcast in SIB (system information block) messages. Therefore, the activation time of HARQ feedback can be determined by when the configuration message is transmitted, which implies that when the configuration message should be transmitted can be determined based on the desired timing when the HARQ feedback configuration should be activated.

For HARQ feedback configuration {K, N} where M=1 so M is not indicated (i.e., the indication of M can be omitted if M=1, in this case, only K and N need to be indicated to the terminal device 120) , the network device 110 allocates only UL resource for the ACK/NACK associated with the K-th TB. The DCI contains a field indicating UL resource for HARQ feedback, for example, the 4-bit “HARQ-ACK resource field” in DCI format N1 for NB-IoT. The terminal device 120 uses only this field to transmit the ACK/NACK associated with the K-th TB on the indicated UL resource.

The network device 110 can schedule control messages (for example, MAC CE or RRC) on the K-th TB so its reception can be acknowledged. For MAC CE commands, their activation can take place after the network device 110 receives an ACK bit, as required by legacy LTE/NR systems. The network device 110 can also use the received ACK/NACK to perform outer-loop link adaptation, adjusting MCS and codeword repetitions for reliable data transmissions. The scheduler of the network device 110 can also decide if stop-and-wait protocol should be observed, considering the tradeoff of transmission reliability and link throughput. For example, for a terminal device 120 with few HARQ processes, the scheduler of the network device 110 may decide to transmit new data on the same HARQ process without waiting for an ACK bit to avoid HARQ stalling and therefore improve throughput.

The configurable HARQ feedback rate enables the network device 110 to receive acknowledgement of control messages and perform link adaptation while improving user throughput in NTN deployment scenarios (where the round-trip time is much longer than a TTI) . Moreover, reduced ACK/NACK transmissions also lead to power saving for the terminal device 120, which is critical for IoT devices.

FIG. 7 illustrates a flowchart 700 of a method implemented at a terminal device in accordance with some other embodiments of the present disclosure. For the purpose of discussion, the method 700 will be described from the perspective of the terminal device 120 with reference to FIG. 1.

At block 710, the terminal device 120 receives, from the network device 120, a HARQ feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device 120 and the network device 110. At block 720, the terminal device 120 transmits the HARQ feedback to the network device 110 or receives HARQ feedback from the network device 110 based on the fractional feedback rate.

In some example embodiments, the fractional feedback rate is M/N and N is an integer greater than 1, M is an integer less than N but no less than 1.

In some example embodiments, the transmitting the HARQ feedback comprises: transmitting M HARQ feedback indications for N TBs scheduled by single DCI.

In some example embodiments, the HARQ feedback indication is transmitted after receiving a K _i-th TB among the N TBs, and any of K _i is an integer equal to or less than N, i being one of {1, 2, …, M} .

In some example embodiments, the HARQ feedback configuration indicates the fractional feedback rate by indicating a value of M, a value of N and value (s) of K _i.

In some example embodiments, the HARQ feedback indication is indicative of one of the following: decoding status of the K _i-th TB, or combined decoding status of previous K _i TBs among the N TBs.

In some example embodiments, the DCI comprises a field indicating an allocated uplink resource for the HARQ feedback indication for the K _i-th TB, respectively, without indicating allocated uplink resources for HARQ feedback for other (N-M) TBs.

In some example embodiments, the K _i-th TB is used to receive at least one of a MAC CE or a RRC message.

In some example embodiments, the HARQ feedback configuration is received via at least one of an MAC CE or an RRC message.

In some example embodiments, the terminal device is in a non-terrestrial network.

FIG. 8 illustrates another flowchart 1800 of a method implemented at a network device in accordance with some other embodiments of the present disclosure. For the purpose of discussion, the method 800 will be described from the perspective of the network device 110 with reference to FIG. 1.

At block 810, the network device 110 transmits, to the terminal device 120, a HARQ feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device 120 and a network device 110. At block 820, the network device 110 receives HARQ feedback from the terminal device 120 or transmits HARQ feedback to the terminal device 120 based on the fractional feedback rate.

In some example embodiments, the receiving HARQ feedback comprises: receiving M HARQ feedback indications for N TBs scheduled by single DCI.

In some example embodiments, the HARQ feedback indication is received after transmitting a K _i-th TB among the N TBs, and K _i is an integer equal to or less than N, i being one of {1, 2, …, M} .

In some example embodiments, the method further comprises: activating the HARQ feedback configuration after receiving, from the terminal device, a HARQ feedback indication that a TB comprising the HARQ feedback configuration is successfully received.

In some example embodiments, the method further comprises: determining an activation time of the HARQ feedback configuration based on a time point when the HARQ feedback configuration is transmitted and a delay.

In some example embodiments, the method further comprises: determining the delay based on a processing delay of the terminal device, a round trip delay, and a processing delay of the network device.

In some example embodiments, the method further comprises: scheduling at least one of a MAC CE or RRC message on the K _i-th TB.

In some example embodiments, the method further comprises: determining the HARQ feedback configuration based on at least one of the following: required latency for reliable data transfer; downlink channel quality report (DCQR) from the terminal device; a propagation loss change rate; or an uplink traffic load.

In some example embodiments, the HARQ feedback configuration is transmitted via at least one of an MAC CE or an RRC message.

In some example embodiments, the network device is in a non-terrestrial network.

In some embodiments, an apparatus capable of performing any of the method 700 (for example, the terminal device 120) 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.

In some example embodiments, the apparatus comprises: means for receiving, at a terminal device from a network device, a hybrid automatic repeat request (HARQ) feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and the network device; and means for transmitting the HARQ feedback to the network device or receive HARQ feedback from the network device based on the fractional feedback rate.

In some example embodiments, the means for transmitting the HARQ feedback to the network device or receive HARQ feedback from the network device based on the fractional feedback rate comprises means for transmitting M HARQ feedback indications for N TBs scheduled by single DCI.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 700. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

In some embodiments, an apparatus capable of performing any of the method 800 (for example, the network device 110) may comprise means for performing the respective steps of the method 800. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some example embodiments, the apparatus comprises: means for transmitting, to a terminal device, a HARQ feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and a network device; and means for receiving HARQ feedback from the terminal device or transmit HARQ feedback to the terminal device based on the fractional feedback rate.

In some example embodiments, the means for receiving HARQ feedback from the terminal device or transmit HARQ feedback to the terminal device based on the fractional feedback rate comprises means for receiving M HARQ feedback indications for N TBs scheduled by single DCI.

In some example embodiments, the HARQ feedback indication is received after transmitting a K _i-th TB among the N TBs, and any of K _i is an integer equal to or less than N, i being one of {1, 2, …, M} .

In some example embodiments, the apparatus further comprises: means for activating the HARQ feedback configuration after receiving, from the terminal device, a HARQ feedback indication that a TB comprising the HARQ feedback configuration is successfully received.

In some example embodiments, the apparatus further comprises: means for determining an activation time of the HARQ feedback configuration based on a time point when the HARQ feedback configuration is transmitted and a delay.

In some example embodiments, the apparatus further comprises: means for determining the delay based on a processing delay of the terminal device, a round trip delay, and a processing delay of the network device.

In some example embodiments, the apparatus further comprises: means for scheduling at least one of a MAC CE or RRC message on the K _i-th TB.

In some example embodiments, the apparatus further comprises: means for determining the HARQ feedback configuration based on at least one of the following: required latency for reliable data transfer; downlink channel quality report (DCQR) from the terminal device; a propagation loss change rate; or an uplink traffic load.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 800. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

FIG. 9 illustrates a simplified block diagram of a device1900 that is suitable for implementing some example embodiments of the present disclosure. The device 900 may be provided to implement a communication device, for example, the core network device 110 or the terminal devices 120 as shown in FIG. 1. As shown, the device 900 includes one or more processors 910, one or more memories 920 coupled to the processor 910, and one or more communication modules 940 coupled to the processor 910.

The communication module 940 is for bidirectional communications. The communication module 940 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 910 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 900 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 920 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) 924, 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) 922 and other volatile memories that will not last in the power-down duration.

A computer program 930 includes computer executable instructions that are executed by the associated processor 910. The program 930 may be stored in the ROM 924. The processor 910 may perform any suitable actions and processing by loading the program 930 into the RAM 922.

The embodiments of the present disclosure may be implemented by means of the program 930 so that the device 900 may perform any process of the disclosure as discussed with reference to FIGS. 2 to 3. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

In some example embodiments, the program 930 may be tangibly contained in a computer-readable medium which may be included in the device 900 (such as in the memory 920) or other storage devices that are accessible by the device 900. The device 900 may load the program 930 from the computer-readable medium to the RAM 922 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. 10 illustrates a block diagram of an example of a computer-readable medium 1000 in accordance with some example embodiments of the present disclosure. The computer-readable medium 1000 has the program 930 stored thereon. It is noted that although the computer-readable medium 1000 is depicted in form of CD or DVD in FIG. 10, the computer-readable medium 1000 may be in any other form suitable for carry or hold the program 930.

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

method

700 or 800 as described above with reference to FIGs. 7 or 8. 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 terminal device comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device to:

receive, from a network device, a hybrid automatic repeat request (HARQ) feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and the network device; and

transmit HARQ feedback to the network device or receive HARQ feedback from the network device based on the fractional feedback rate.
The terminal device of claim 1, wherein the fractional feedback rate is M/N and N is an integer greater than 1, M is an integer less than N but no less than 1.
The terminal device of claim 2, wherein the terminal device is caused to transmit the HARQ feedback by:

transmitting M HARQ feedback indications for N transport blocks (TB) scheduled by single downlink control information (DCI) .
The terminal device of claim 3, wherein the HARQ feedback indication is transmitted after receiving a K _i-th TB among the N TBs, and any of K _i is an integer equal to or less than N, i being one of {1, 2, …, M} .
The terminal device of claim 4, wherein the HARQ feedback configuration indicates the fractional feedback rate by indicating a value of M, a value of N and value (s) of K _i.
The terminal device of claim 4 or 5, wherein the HARQ feedback indication is indicative of one of the following:

decoding status of the K _i-th TB, or

combined decoding status of previous K _i TBs among the N TBs.
The terminal device of any of claims 4-6, wherein the DCI comprises a field indicating an allocated uplink resource for the HARQ feedback indication for the K _i-th TB, respectively, without indicating allocated uplink resources for HARQ feedback for other (N-M) TBs.
The terminal device of any of claims 4-7, wherein the K _i-th TB is used to receive at least one of a medium access control (MAC) control element (CE) or a radio resource control (RRC) message.
The terminal device of any of claims 1-8, wherein the HARQ feedback configuration is received via at least one of an MAC CE or an RRC message.
The terminal device of any of claims 1-9, wherein the terminal device is in a non-terrestrial network.
A network device comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the network device to:

transmit, to a terminal device, a hybrid automatic repeat request (HARQ) feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and the network device; and

receive HARQ feedback from the terminal device or transmit HARQ feedback to the terminal device based on the fractional feedback rate.
The network device of claim 11, wherein the fractional feedback rate is M/N and N is an integer greater than 1, M is an integer less than N but no less than 1.
The network device of claim 12, wherein the network device is caused to receive the HARQ feedback by:

receiving M HARQ feedback indications for N transport blocks (TB) scheduled by single downlink control information (DCI) .
The network device of claim 13, wherein the HARQ feedback indication is received after transmitting a K _i-th TB among the N TBs, and K _i is an integer equal to or less than N, i being one of {1, 2, …, M} .
The network device of claim 14, wherein the HARQ feedback configuration indicates the fractional feedback rate by indicating a value of M, a value of N and value (s) of K _i.
The network device of claim 14 or 15, wherein the HARQ feedback indication is indicative of one of the following:

decoding status of the K _i-th TB, or

combined decoding status of previous K _i TBs among the N TBs.
The network device of any of claims 14-16, wherein the DCI comprises a field indicating an allocated uplink resource for the HARQ feedback indication for the K _i-th TB, respectively, without indicating allocated uplink resources for HARQ feedback for other (N-M) TBs.
The network device of any of claims 11-17, wherein the network device is further caused to:

activate the HARQ feedback configuration after receiving, from the terminal device, a HARQ feedback indication that a TB comprising the HARQ feedback configuration is successfully received.
The network device of claim 18, wherein the network device is further caused to:

determine an activation time of the HARQ feedback configuration based on a time point when the HARQ feedback configuration is transmitted and a delay.
The network device of claim 19, wherein the network device is further caused to:

determine the delay based on a processing delay of the terminal device, a round trip delay, and a processing delay of the network device.
The network device of any of claims 14-20, wherein the network device is further caused to:

schedule at least one of a medium access control (MAC) control element (CE) or radio resource control (RRC) message on the K _i-th TB.
The network device of any of claims 11-21, wherein the network device is further caused to determine the HARQ feedback configuration based on at least one of the following:

required latency for reliable data transfer;

downlink channel quality report (DCQR) from the terminal device;

a propagation loss change rate; or

an uplink traffic load.
The network device of any of claims 11-22, wherein the HARQ feedback configuration is transmitted via at least one of an MAC CE or an RRC message.
The network device of any of claims 11-23, wherein the network device is in a non-terrestrial network.
A method comprising:

receiving, at a terminal device from a network device, a hybrid automatic repeat request (HARQ) feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and the network device; and

transmitting the HARQ feedback to the network device or receiving HARQ feedback from the network device based on the fractional feedback rate.
A method comprising:

transmitting, to a terminal device, a hybrid automatic repeat request (HARQ) feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and a network device; and

receiving HARQ feedback from the terminal device or transmitting HARQ feedback to the terminal device based on the fractional feedback rate.
An apparatus comprising:

means for receiving, at a terminal device from a network device, a hybrid automatic repeat request (HARQ) feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and the network device; and

means for transmitting the HARQ feedback to the network device or receiving HARQ feedback from the network device based on the fractional feedback rate.
An apparatus comprising:

means for transmitting, to a terminal device, a hybrid automatic repeat request (HARQ) feedback configuration indicating a fractional feedback rate for HARQ feedback between the terminal device and a network device; and; and

means for receiving HARQ feedback from the terminal device or transmitting HARQ feedback to the terminal device based on the fractional feedback rate.
A non-transitory computer readable medium comprising program instructions stored thereon for performing at least any of the method of claim 25 or 26.