CN114556833A - Discontinuous reception mechanism supporting blind retransmission - Google Patents

Abstract

Example embodiments of the present disclosure relate to Discontinuous Reception (DRX) mechanisms. According to some example embodiments, a first device receives control information from a second device, the control information indicating a first retransmission scheme to be applied for transmission of data between the first device and the second device, the first retransmission scheme requiring retransmission of the data to be performed independently of feedback on previous transmissions of the data. The first device also receives timing information specific to the first retransmission scheme from the second device, the timing information indicating retransmission timing, and determines timing for monitoring further control information from the second device for scheduling retransmissions based on the retransmission timing. This solution provides scheduling and transmission flexibility for retransmission schemes.

Description

Discontinuous reception mechanism supporting blind retransmission

Technical Field

Embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly, to methods, devices, apparatuses, and computer-readable storage media for Discontinuous Reception (DRX).

Background

With the development of communication systems, new technologies have been proposed. Third generation partnership project (3GPP) release (Rel)16 includes information about how the fifth generation (5G) New Radio (NR) standard supports non-terrestrial network (NTN) deployments using satellites and High Altitude Platform Stations (HAPS) to provide connectivity across a wide service area. In many NTN deployment scenarios, the Round Trip Time (RTT) for signal propagation may be much longer than for terrestrial networks for NR interfaces. Therefore, these long propagation delays may pose challenges for Discontinuous Reception (DRX) in hybrid automatic repeat request (HARQ) processes for retransmission of erroneous packets. It is therefore desirable to improve DRX operation in scenarios with longer RTT delays, such as in NTN.

Disclosure of Invention

In general, example embodiments of the present disclosure provide a solution for DRX that may be applied to communication scenarios such as, but not limited to, supporting blind retransmissions.

In a first aspect, a first device is provided. The first device comprises at least one processor; and at least one memory including computer program code; wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the first device to: receiving control information from the second device, the control information indicating a first retransmission scheme to be applied for transmission of data between the first device and the second device, the first retransmission scheme requiring retransmission of the data to be performed independently of feedback on previous transmissions of the data; receiving timing information specific to a first retransmission scheme from a second device, the timing information indicating retransmission timing; and determining a timing for monitoring further control information from the second device for scheduling retransmissions based on the retransmission timing.

In a second aspect, a first apparatus is provided. The first device comprises at least one processor; and at least one memory including computer program code; wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the first apparatus to: receiving, from a second device, a first configuration of a first timer for a first retransmission scheme; receiving, from the second device, a second configuration of a second timer for a second retransmission scheme different from the first retransmission scheme; and in accordance with a determination that the first retransmission scheme is to be applied to transmission of data between the first device and the second device, setting a first value for the first timer based on the first configuration or both the first configuration and the second configuration.

In a third aspect, a second apparatus is provided. The second device comprises at least one processor; and at least one memory including computer program code; wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the second apparatus to: transmitting control information to the first device, the control information indicating a first retransmission scheme to be applied for transmission of data between the first device and the second device, the first retransmission scheme requiring retransmission of the data to be performed independently of feedback on previous transmissions of the data; and transmitting, to the first device, timing information specific to the first retransmission scheme, the timing information indicating retransmission timing to configure timing for the first device to monitor further control information from the second device for scheduling retransmissions.

In a fourth aspect, a second apparatus is provided. The second device comprises at least one processor; and at least one memory including computer program code; wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the second apparatus to: transmitting, to a first device, a first configuration of a first timer of the first device for a first retransmission scheme; transmitting, to the first device, a second configuration of a second timer of the first device for a second retransmission scheme different from the first retransmission scheme; and sending control information to the first device indicating that the first retransmission scheme is to be applied for transmission of data between the first device and the second device, wherein the first configuration or a combination of the first configuration and the second configuration determines the first value for the first timer.

In a fifth aspect, a method is provided. The method comprises the following steps: receiving, at a first device, control information from a second device, the control information indicating a first retransmission scheme to be applied for transmission of data between the first device and the second device, the first retransmission scheme requiring retransmission of the data to be performed independently of feedback on previous transmissions of the data; receiving timing information specific to a first retransmission scheme from a second device, the timing information indicating retransmission timing; and determining a timing for monitoring further control information from the second device for scheduling retransmissions based on the retransmission timing.

In a sixth aspect, a method is provided. The method comprises the following steps: receiving, at a first device and from a second device, a first configuration of a first timer for a first retransmission scheme; receiving, from the second device, a second configuration of a second timer for a second retransmission scheme different from the first retransmission scheme; and in accordance with a determination that the first retransmission scheme is to be applied to transmission of data between the first device and the second device, setting a first value for the first timer based on the first configuration or both the first configuration and the second configuration.

In a seventh aspect, a method is provided. The method comprises the following steps: transmitting, at the second device and to the first device, control information indicating a first retransmission scheme to be applied for transmission of data between the first device and the second device, the first retransmission scheme requiring retransmission of the data to be performed independently of feedback on previous transmissions of the data; and transmitting, to the first device via a physical layer downlink control channel, timing information specific to the first retransmission scheme, the timing information indicating retransmission timing to configure timing for the first device to monitor further control information from the second device for scheduling retransmissions.

In an eighth aspect, a method is provided. The method comprises the following steps: transmitting, at the second device and to the first device, a first configuration of a first timer of the first device for a first retransmission scheme; transmitting, to the first device, a second configuration of a second timer of the first device for a second retransmission scheme different from the first retransmission scheme; and sending control information to the first device, the control information indicating that the first retransmission scheme is to be applied for transmission of data between the first device and the second device, wherein the first configuration or a combination of the first configuration and the second configuration determines the first value for the first timer.

In a ninth aspect, a first apparatus is provided. The first device comprises means for: receiving control information from the second apparatus, the control information indicating a first retransmission scheme to be applied for transmission of data between the first apparatus and the second apparatus, the first retransmission scheme requiring retransmission of the data to be performed independently of feedback on previous transmissions of the data; receiving timing information specific to a first retransmission scheme from a second apparatus, the timing information indicating retransmission timing; and determining a timing for monitoring further control information from the second apparatus for scheduling retransmissions based on the retransmission timing.

In a tenth aspect, a first apparatus is provided. The first device comprises means for: receiving, from a second apparatus, a first configuration of a first timer for a first retransmission scheme; receiving, from a second apparatus, a second configuration of a second timer for a second retransmission scheme different from the first retransmission scheme; and in accordance with a determination that the first retransmission scheme is to be applied to transmission of data between the first apparatus and the second apparatus, setting a first value for the first timer based on the first configuration or both the first configuration and the second configuration.

In an eleventh aspect, a second apparatus is provided. The second device comprises means for: transmitting control information to the first apparatus, the control information indicating a first retransmission scheme to be applied for transmission of data between the first apparatus and the second apparatus, the first retransmission scheme requiring retransmission of the data to be performed independently of feedback on previous transmissions of the data; and transmitting, to the first apparatus via a physical layer downlink control channel, timing information specific to the first retransmission scheme, the timing information indicating retransmission timing to monitor, for the first apparatus, further control information configuration timing from the second apparatus for scheduling retransmissions.

In a twelfth aspect, a second apparatus is provided. The second device comprises means for: transmitting, to a first apparatus, a first configuration of a first timer of the first apparatus for a first retransmission scheme; transmitting, to the first apparatus, a second configuration of a second timer of the first apparatus for a second retransmission scheme different from the first retransmission scheme; and means for transmitting, to the first apparatus, control information indicating that the first retransmission scheme is to be applied for transmission of data between the first apparatus and the second apparatus, wherein the first configuration or a combination of the first configuration and the second configuration determines the first value for the first timer.

In a thirteenth aspect, a computer-readable medium is provided. The computer readable medium comprises program instructions for causing an apparatus to at least perform the method according to any of the above fifth and eighth aspects.

It should be understood that the summary is not intended to identify key or essential features of embodiments of the disclosure, nor is it intended to be used to limit the scope of the disclosure. Other features of the present disclosure will become readily apparent from the following description.

Drawings

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

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

fig. 2 illustrates a signaling flow for data retransmission according to some example embodiments of the present disclosure;

fig. 3 illustrates a signaling flow for data retransmission in the Downlink (DL) according to some example embodiments of the present disclosure;

fig. 4 illustrates a signaling flow for data retransmission in the Uplink (UL) according to some example embodiments of the present disclosure;

fig. 5 illustrates a signaling flow for data retransmission in the DL according to some other example embodiments of the present disclosure;

fig. 6 illustrates a signaling flow for data retransmission according to some other example embodiments of the present disclosure;

fig. 7 illustrates a signaling flow for data retransmission in the DL according to some other example embodiments of the present disclosure;

fig. 8 illustrates a signaling flow for data retransmission in the UL according to some other example embodiments of the present disclosure;

fig. 9 illustrates a signaling flow for data retransmission in the DL according to some other example embodiments of the present disclosure;

fig. 10 illustrates a signaling flow for data retransmission in the UL according to some other example embodiments of the present disclosure;

fig. 11 illustrates a flow chart of a method implemented at a first device, according to some example embodiments of the present disclosure;

fig. 12 illustrates a flow chart of a method implemented at a first device, according to some other example embodiments of the present disclosure;

fig. 13 illustrates a flow chart of a method implemented at a second device, according to some example embodiments of the present disclosure;

fig. 14 illustrates a flow chart of a method implemented at a second device, according to some other example embodiments of the present disclosure;

FIG. 15 illustrates a simplified block diagram of an apparatus suitable for implementing an example embodiment of the present disclosure; and

fig. 16 illustrates a block diagram of an example computer-readable medium, in accordance with some example embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numbers refer to the same or similar elements.

Detailed Description

The principles of the present disclosure will now be described with reference to a few exemplary embodiments. It is understood that these examples are described merely to illustrate and assist those of ordinary skill in the art in understanding and practicing the disclosure, and are not intended to limit the scope of the disclosure in any way. The disclosure described herein may be implemented in a variety of other ways besides those 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 skill in the art to which this disclosure belongs.

References in the present disclosure to "one embodiment," "an example embodiment," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include 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 will be understood that, although the terms first, 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 may be termed a second element, and, similarly, a second element may 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," "contains" and/or "containing," when used herein, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof.

As used in this application, the term "circuitry" may refer to one or more or all of the following:

(a) a purely hardware circuit implementation (such as an implementation using only analog and/or digital circuitry), and

(b) a combination of hardware circuitry and software, such as (as applicable):

(i) combinations of analog and/or digital hardware circuit(s) and software/firmware, and

(ii) hardware processor(s) with software (including digital signal processor (s)), software, and any portion of memory(s) that work together to cause a device, such as a mobile phone or server, to perform various functions, and

(c) hardware circuit(s) and/or processor(s), such as microprocessor(s) or a portion of microprocessor(s), that require software (e.g., firmware)

For operation, but software may not be present when operation is not required.

The definition of circuitry applies to all uses of the term in this application, including in any claims. As a further example, as used in this application, the term circuitry also encompasses implementations of only 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. For example, if applicable to the particular claim element, the term circuitry also encompasses a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in a server, a cellular network device, or other computing or network device.

As used herein, the term "communication network" refers to a network that conforms to any suitable communication standard, such as New Radio (NR), Long Term Evolution (LTE), LTE-advanced (LTE-a), Wideband Code Division Multiple Access (WCDMA), High Speed Packet Access (HSPA), narrowband internet of things (NB-IoT), and so forth. Further, communication between the terminal device and the network device in the communication network may be performed according to any appropriate generation of communication protocol, including but not limited to first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, future fifth generation (5G) communication protocols, and/or any other protocol currently known or developed in the future. Embodiments of the present disclosure may be applied to various communication systems. In view of the rapid development of communications, there will, of course, also be future types of communication techniques and systems in which the present disclosure may be implemented. And should not be taken as limiting the scope of the disclosure to only the above-described systems.

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. A network device may refer to a Base Station (BS) or an Access Point (AP), e.g., a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), an NR NB (also known as a gNB), a Remote Radio Unit (RRU), a Radio Head (RH), a Remote Radio Head (RRH), a relay, a low power node (such as a femto, pico), a non-terrestrial network (NTN), or a non-terrestrial network device (such as a satellite network device, a Low Earth Orbit (LEO) satellite, and a Geosynchronous Earth Orbit (GEO) satellite), an aircraft network device, etc., depending on the terminology and technology applied.

The term "terminal device" refers to any terminal device capable of wireless communication. By way of example, and not 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 end devices may include, but are not limited to, mobile phones, cellular phones, smart phones, voice over IP (VoIP) phones, wireless local loop phones, tablet computers, wearable end devices, Personal Digital Assistants (PDAs), portable computers, desktop computers, image capture end devices such as digital cameras, gaming end devices, music storage and playback devices, in-vehicle wireless end devices, wireless endpoints, mobile stations, laptop embedded devices (LEEs), laptop installed devices (LMEs), USB dongles, smart devices, wireless client devices (CPEs), internet of things (IoT) devices, watches or other wearable devices, Head Mounted Displays (HMDs), vehicles, drones, medical devices and applications (e.g., tele-surgery), industrial devices and applications (e.g., robots and/or other wireless devices operating in industrial and/or automated processing chain environments), Consumer electronics devices, devices 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.

Example Environment and principles of operation

Fig. 1 illustrates an example communication system 100 in which example embodiments of the present disclosure may be implemented. In the example of fig. 1, two types of communication networks are shown, including a non-terrestrial network (NTN) or non-terrestrial network having one or more NTN network devices or non-terrestrial network devices for providing communication coverage, and a Terrestrial Network (TN) or terrestrial network having one or more terrestrial or terrestrial network devices for providing communication coverage.

In an NTN network, a first device 110-1 and a second device 120-1 may communicate with each other. In this example, the first device 110-1 is illustrated as a terminal device and the second device 120-1 is illustrated as an NTN network device serving the terminal device. The service area of the second device 120-1 is referred to as a cell 102-1. In a TN network, a first device 110-2 and a second device 120-2 may communicate with each other. In this example, the first device 110-2 is illustrated as a terminal device and the second device 120-2 is illustrated as a TN network device serving the terminal device. The service area of the second device 120-2 is referred to as a cell 102-2. For ease of discussion, in the following, the first devices 110-1 and 110-2 are collectively or individually referred to as first devices 110, the second devices 120-1 and 120-2 are collectively or individually referred to as second devices 120, and the cells 102-1 and 102-2 are collectively or individually referred to as cells 102.

It should be understood that the number of first devices and second devices is for illustrative purposes only and does not represent any limitation. Communication system 100 may include any suitable number of first and second devices suitable for implementing embodiments of the present disclosure. Although not shown, it is to be understood that one or more additional terminal devices may be located in the cell 102 and served by the second device 120.

Communications in communication system 100 may be implemented in accordance with any suitable communication protocol(s), including, but not limited to, first-generation (1G), second-generation (2G), third-generation (3G), fourth-generation (4G), and fifth-generation (5G), etc. cellular communication protocols, wireless local area network communication protocols, such as Institute of Electrical and Electronics Engineers (IEEE)802.11, etc., and/or any other protocol currently known or developed in the future. Further, the communication may utilize any suitable wireless communication technology, including but not limited to: code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Frequency Division Duplex (FDD), Time Division Duplex (TDD), Multiple Input Multiple Output (MIMO), Orthogonal Frequency Division Multiplexing (OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM), and/or any other technique now known or later developed.

In the communication system 100, the first device 110 and the second device 120 may communicate data and control information with each other. In the case where the first device 110 is a terminal device and the second device 120 is a network device, a link from the second device 120 to the first device 110 is referred to as a Downlink (DL), and a link from the first device 110 to the second device 120 is referred to as an Uplink (UL). In the DL, the second device 120 is a Transmitting (TX) device (or transmitter) and the first device 110 is a Receiving (RX) device (or receiver). In the UL, the first device 110 is a TX device (or transmitter) and the second device 120 is an RX device (or receiver).

In operation, the first device 110 may monitor control information from the second device 120 that schedules an assignment (e.g., a DL assignment) for a transmission from the second device 120 to the first device 110 or schedules a grant (e.g., a UL grant) for a transmission from the first device 110 to the second device 120. By reducing the time to monitor control information from the second device 120 and enter an inactive state, Discontinuous Reception (DRX) may be applied to support battery savings for the first device 110.

In some scenarios, the propagation delay between the transmitter and the receiver is relatively large, resulting in a long Round Trip Time (RTT), especially for NTN. Conventional DRX mechanisms may not be suitable for communications with long propagation delays.

It is well known that any system with a propagation delay greater than the number of available hybrid automatic repeat request (HARQ) processes may suffer from HARQ stalls. High transmission delays in NTN, especially with GEO satellite network equipment, would require the transmitter to maintain a large number of HARQ processes, which may not be impractical due to the extreme buffer size requirements of the receiver soft buffer and the large signaling requirements for indicating the number of HARQ processes. In addition, retransmission also results in a longer delay time for the packet. However, in both TN networks and NTN networks, HARQ has a valuable gain in providing reliability at a lower cost (compared to automatic repeat request (ARQ)) due to the gains of soft combining and shorter delay (compared to ARQ).

Therefore, it may be advantageous to allow HARQ enablement and disablement, especially for NTN. For example, for NTN, the network device may disable UL HARQ feedback for DL transmissions at the terminal device, e.g., to support long propagation delays. The enabling/disabling of HARQ feedback may be signaled semi-statically to the terminal device by Radio Resource Control (RRC) signaling. The enabling/disabling of HARQ feedback for DL transmissions may be configured via RRC signaling for each terminal device and for each HARQ process, but dynamic enabling and disabling of HARQ for HARQ processes is also possible. Further, for NTN, the network may disable HARQ UL retransmissions at the terminal device. The enabling/disabling of HARQ UL retransmissions may be configured per terminal device, per HARQ process, and per Logical Channel (LCH).

If HARQ feedback is disabled, some open loop/blind retransmission (e.g., retransmission without feedback, or retransmission independent of HARQ feedback) mechanism should be considered. With blind retransmission, the network device can schedule retransmission at any time, regardless of feedback. Since blind retransmission has the advantages of reducing delay, improving reliability and dynamically scheduling retransmission resources, blind retransmission is a very promising retransmission scheme, especially for scenarios with large propagation delay.

In summary, in at least NTN, possible (re) transmission schemes may include: 1) single transmission only with HARQ disabled (i.e., HARQ is disabled with one-time data transmission and no retransmission), 2) blind retransmission with an aggregation factor greater than 1 with HARQ disabled (i.e., consecutive multiple transmissions of one Transport Block Set (TBS) that are not based on feedback or decoding results), 3) blind retransmission scheduled with downlink control information with HARQ disabled (i.e., multiple transmissions of one TBS over a sparse TTI that is not based on feedback or decoding results, with scheduling flexibility and gain advantages), and 4) HARQ enabled retransmission based on feedback or decoding results, including blind retransmission over legacy HARQ.

Considering that there are multiple types of retransmission schemes, it is not desirable to design a DRX solution by considering only HARQ-enabled transmissions. In contrast, when designing DRX solutions, HARQ-disabled transmissions, such as blind retransmissions, should also be considered. One possible DRX solution to support blind retransmission schemes may be to extend the active time of the terminal device by extending the values set for one or more timers used in DRX. It is desirable to improve DRX solutions in view of the specific characteristics of blind retransmissions in order to balance power consumption (i.e. the effective time to monitor control information) and scheduling and transmission flexibility.

According to various example embodiments of the present disclosure, some improved DRX solutions are provided to accommodate the specific characteristics of a given retransmission scheme. In particular, in some example embodiments of the present disclosure, if a retransmission scheme is applied to the transmission of data between a first device and a second device, a timer for the retransmission scheme to monitor timing of control information from the second device or to control an active/inactive state of the first device is configured exclusively for the first device by the second device. In one solution, retransmission timing is dynamically provided by a second device for timing of a first device determining control information for entering an active state for monitoring for scheduled data retransmissions from the second device. In another solution, the value of the timer for DRX used in the retransmission scheme is specifically set based on the configuration of the timer or on a combination of the configuration of the timer of the retransmission scheme and a further configuration of a different retransmission scheme. These solutions provide scheduling and transmission flexibility for retransmission schemes. Based on the configuration of the timer or the value of the timer configured for the active state, the first device may receive control information from the second device in time with optimized power saving.

Example embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

DRX based on dynamic retransmission timing

Referring now to fig. 2, fig. 2 illustrates a signaling flow 200 for data retransmission according to some example embodiments of the present disclosure. For purposes of discussion, signaling flow 200 will be described with reference to fig. 1. The signaling flow 200 may involve the first device 110 and the second device 120 as shown in fig. 1. In some example embodiments, the signaling flow 200 may be particularly beneficial in scenarios where the RTT between the first device 110 and the second device 120 may be relatively large. For example, the signaling flow 200 may involve the first device 110-1 and the second device 120-1 in an NTN network as shown in fig. 1. It should be understood that signaling flow 200 may also be implemented in any other communication network.

In the signaling flow 200, the second device 120 sends 205 control information to the first device 110. The control information indicates a retransmission scheme (referred to as a "first retransmission scheme" for ease of discussion) to be applied to transmitting data between the first device 110 and the second device 120. The first retransmission scheme requires that the retransmission of data is performed independently of feedback on previous transmissions of data. That is, the first retransmission scheme is a blind retransmission scheme. The transmission/retransmission between the first device 110 and the second device 120 may be associated with a HARQ process.

According to a first retransmission scheme, the sender sends data to the receiver and retransmits the data without waiting for feedback on previous transmissions, which means that the sender always performs multiple transmissions of the same data as planned, regardless of whether the previous transmissions were successfully received and detected by the receiver. For example, a Medium Access Control (MAC) entity schedules the same data on the same HARQ process without a New Data Indicator (NDI) being handed over. Such blind retransmissions may help to reduce the residual block error rate (BLER), especially if the feedback of HARQ is disabled.

In some example embodiments, the first retransmission scheme may also require dynamic scheduling. That is, the second device 120, such as a network device, may dynamically schedule retransmissions. If the first retransmission scheme is supported, the second device 120 may schedule retransmissions at any time without waiting for feedback on previous transmissions. In some example embodiments, the scheduling of retransmissions and the retransmission scheme are indicated via different signaling messages. In some other example embodiments, the schedule of transmission/retransmission may also be indicated in the control information. For example, for a retransmission from the second device 120 to the first device 110, the control information may indicate an assignment (e.g., a DL assignment) for the retransmission, so that the first device 110 may know when and where to detect the retransmission after receiving the assignment. For a retransmission from the first device 110 to the second device 120, the control information may indicate a grant (e.g., a UL grant) for the retransmission, so that the first device 110 may know when and where to perform the retransmission to the second device after receiving the grant.

In some example embodiments, the first device 110 receives 210 the control information and may therefore know not only the assignment or grant for transmission of the data, but also the first retransmission scheme to be applied for retransmission of the data.

For a retransmission from the second device 120 to the first device 110 (e.g., a DL retransmission) or a retransmission from the first device 110 to the second device 120 (e.g., an UL retransmission), the second device 120 may send control information indicating whether the first retransmission scheme is applied to subsequent retransmissions. In some example embodiments, the control information may be sent via a physical layer downlink control channel (e.g., PDCCH). In this example, the control information may also be referred to as DL control information (i.e., DCI). In some example embodiments, the control information may include an indication to enable/disable HARQ feedback to indicate the first retransmission scheme. For example, if the indication indicates that HARQ feedback is disabled, the first device 110 may determine that the first retransmission scheme is to be applied for retransmission. Alternatively or additionally, the control information may comprise an indication for the retransmission scheme, which indication may be used to explicitly indicate the first retransmission scheme to be applied.

In case the first retransmission scheme is to be applied for transmissions between the first device 110 and the second device 120, the second device 120 also sends 215 to the first device 110 timing information specific to the first retransmission scheme. The timing information indicates retransmission timing of the first retransmission scheme. The retransmission timing indicates when retransmission of data can be expected or a time interval during which retransmission cannot be expected. In some example embodiments, the timing information may be transmitted by the second device 120 via a physical layer downlink control channel (e.g., PDCCH). The timing information may also be included in the DCI together with control information indicating the first retransmission scheme. Alternatively, in some example embodiments, the control information indicating the first retransmission scheme may be sent via higher layer signaling, while the timing information may be carried in physical layer signaling, such as via a physical layer downlink control channel (e.g., PDCCH). In some example embodiments, the timing information in the DCI may be indicated via different fields depending on whether the transmission is for the DL or UL, which will be described in detail below.

The first device 110 receives 220 the timing information and determines 225 a timing for monitoring further control information from the second device 120 for scheduling retransmissions based on the indicated retransmission timing.

The first device 110 may operate in a DRX mode and may transition between an inactive state and an active state for power saving purposes. In the inactive state, the first device 110 does not need to monitor control information from the second device 120. In the active state, the first device 110 will be in the active state for control information monitoring and may therefore receive a DL assignment or UL grant for data (re) transmission. According to an example embodiment of the present disclosure, since the second device 120 is responsible for scheduling of (re) transmission scheduling, it may be more flexible to dynamically inform the appropriate retransmission timing of the first retransmission scheme. Based on the retransmission timing information, the first device 110 may know when additional control information for scheduling data retransmission from the second device 120 may be expected. Thus, the first device 110 may enter the active state at the correct time to detect and receive additional control information. In some example embodiments, if there are no other running DRX timer(s) that indicate that the first device 110 entered the active state, such as a running inactivity timer, the first device 110 may remain in the inactive state to save power consumption.

In some example embodiments, the retransmission timing may include a time interval within which the first device 110 may be in an inactive state. With an explicit indication of the time interval from the second device 120, the first device 110 may determine to start the retransmission timer after the end of the time interval. In DRX, a retransmission timer may be used by the first device 110 to actively initiate monitoring for control information from the second device 120. The retransmission timer may indicate a maximum duration until a DL retransmission (from the second device 120 to the first device 110) or a UL grant for a UL retransmission (from the first device 110 to the second device 120) is received. In 3 GPP-based communication systems, the retransmission timer may also be referred to as a drx-retransmission timer, drx-retransmission TimerDL, or drx-retransmission TimerUL. The start of the retransmission timer may be triggered dynamically by an indication of the time interval. After the retransmission timer is started, the first device 110 may remain in an active state to monitor for additional control information from the second device 120 until the retransmission timer expires or until additional control information is detected. For example, the value of the retransmission timer may be set via RRC configuration signaling.

It should be appreciated that the timing for entering the active state may be determined for the first device 110 in other ways than a time interval to indicate retransmission timing.

In some example embodiments, to enter the active state based on the indicated retransmission timing, the first device 110 may set the value of the RTT timer to zero, e.g., by starting a retransmission timer. The RTT timer is a DRX timer that indicates a minimum duration before a DL assignment for HARQ based retransmissions (in a DL retransmission from the second device 120 to the first device 110) or a UL grant for HARQ based retransmissions (in a UL retransmission from the first device 110 to the second device 120) is expected. In 3 GPP-based communication systems, the RTT timer may also be referred to as drx-HARQ-RTT-TimerDL (in DL (re) transmission) or drx-HARQ-RTT-timerll (in UL (re) transmission). In some example embodiments, instead of setting the RTT timer to 0, the RTT timer and corresponding functionality may be disabled if the first retransmission scheme is configured.

In some example embodiments, the set of candidate values for retransmission timing for the first retransmission scheme may be configured from the second device 120 to the first device 110 via higher layer signaling, such as RRC signaling. The set of candidate values may be indexed with different indices. For example, if there are eight possible candidates at the retransmission timing, such as retransmission intervals of 10ms, 15ms, 20ms, 25ms, 30ms, etc., the second device 120 may use a 3-bit indication to indicate all of these candidates, such as 000 for 10ms, 001 for 15ms, 010 for 20ms, and so on. The second device 120 may configure the candidate values and the mapping between the candidate values and the 3-bit indication to the first device 110, e.g., via RRC signaling. To indicate the retransmission timing to be applied, the second device 120 may select one of the candidate values to indicate the retransmission timing in the timing information and send the timing information (e.g., a value 010 indicating 20 ms) to the first device 110 via physical layer signaling such as PDCCH, for example.

To configure the set of candidate values to the first device 110 via higher layer signaling, in some example embodiments, a legacy Information Element (IE) of RRC signaling that would not be used if the first retransmission scheme were applied may be reused to carry the set of candidate values. That is, if a different second retransmission scheme (e.g., a retransmission scheme based on HARQ feedback) is applied, the IE of the RRC may have a different meaning. For example, the IE carrying RRC signaling of the timing list for transmitting feedback in case a different retransmission scheme (e.g., a retransmission scheme based on HARQ feedback) is configured may be reused for the set of candidate values indicating retransmission timing in case the first retransmission scheme is applied. An example of such an IE may be the IE "dl-DataToUL-ACK" in a 3 GPP-based communication system. Alternatively, a new IE may be defined in RRC signaling to transmit the set of candidate values to the first device 110.

By dynamically indicating the retransmission timing to the first device 110, the second device 120 may schedule a timer when the first device 110 may initiate monitoring for additional control information in the first retransmission scheme or may initiate a retransmission timer. Retransmission timing (e.g., a time interval during which no retransmission can be expected and during which the first device 110 can be in an inactive state) can be determined based on various factors. In some example embodiments, the second device 120 may determine the retransmission timing based on: channel conditions between the first device 110 and the second device 120, service requirements for data to be transmitted, load conditions within the service coverage of the second device 120, etc.

For example, if the data to be transmitted (e.g., data included in a MAC Protocol Data Unit (PDU)) has a high latency requirement, the second device 120 may schedule a subsequent blind retransmission immediately after a previous transmission of the data. Thus, the retransmission timing may comprise a shorter retransmission interval and the first device 110 may enter an active state in time to receive control information for scheduling subsequent retransmissions. If the data has a lower latency requirement and the second device 120 has a high load, the second device 120 will schedule a blind retransmission long after the previous transmission. As another example, the second device 120 may obtain a channel correlation time under current channel conditions and may determine a likely duration of a subsequent retransmission. The second device 120 may thus inform the first device 110 of the timing for starting the retransmission timer.

DRX solutions based on dynamic retransmission timing have been discussed above. To better understand this solution, some examples of DRX operations to support (re) transmissions from the second device 120 to the first device 110 (e.g., DL (re) transmissions) and from the first device 110 to the second device 120 (e.g., UL (re) transmissions) will be described with reference to fig. 3 and 4, respectively.

DL (re) transmission in DRX based on dynamic retransmission timing

Fig. 3 illustrates a signaling flow 300 in a DL (re) transmission between a first device 110 and a second device 120 according to some example embodiments of the present disclosure. In the example of fig. 3, the first device 110 operates in DRX mode and dynamic retransmission timing is controlled by the second device 120.

In signaling flow 300, the second device 120 transmits 305DCI to the first device 110, e.g., via a physical layer DL control channel. In addition to indicating a DL assignment for transmission of current data, the DCI may indicate that a first retransmission scheme is to be applied. In some example embodiments, the control information indicating that the first retransmission scheme is to be applied is sent by the second device 120 to the first device 110 in separate signaling. The first device 110 monitors and receives 310DCI from the second device 120. Since the first retransmission scheme is indicated in the DCI or another received message, the first device 110 may determine that the second device 120 will schedule a blind retransmission of the data later, regardless of feedback on previous transmissions. If the first retransmission scheme is to be applied, the DCI may further include timing information indicating retransmission timing, such as a retransmission interval (denoted as "K1").

In some example embodiments, a newly defined field in the DCI may be used to indicate retransmission timing. In some other example embodiments, in DL (re-) transmission, if the first retransmission scheme is to be applied, one or more fields of the physical layer DL control channel (e.g., DCI) used in other retransmission schemes requiring feedback (referred to as second retransmission schemes) may not need to carry corresponding parameters for the second retransmission scheme, as these parameters are needed if the feedback is disabled. Such a field in the physical layer DL control channel may be reused to indicate timing information for the first retransmission scheme.

The second retransmission scheme is different from the first retransmission scheme. An example of the second retransmission scheme is a HARQ enabled retransmission scheme requiring feedback, such as a conventional HARQ enabled retransmission scheme. An example of a field to be reused for indicating retransmission timing of the first retransmission scheme may be a field for indicating a feedback timing indicator if the second retransmission scheme requiring feedback is configured. Thus, the reuse field in the DCI may indicate a feedback timing indicator if the second retransmission scheme is configured and may indicate timing information if the first retransmission scheme is configured.

In a 3GPP based communication system, the field indicating the feedback timing indicator may be a field "PDSCH-to-HARQ _ feedback timing indicator", where PDSCH refers to a physical downlink shared channel. The meaning of the PDSCH-to-HARQ feedback timing indicator field may be redefined when the first retransmission scheme is configured. The mapping between the candidate value of retransmission timing and the index to be indicated in the field "PDSCH-to-HARQ _ feedback timing indicator" may be configured by RRC signaling, for example, in an Information Element (IE) "dl-DataToUL-ACK". By reusing existing field(s), signaling efficiency can be improved and impact on communication standards due to the introduction of retransmission timing will be minimized.

When the first device 110 receives the control information and timing information indicating the first retransmission scheme, the first device 110 may extract the retransmission timing indicated by the timing information (such as "K1"). In some example embodiments, if the DCI also indicates that a new transmission of new data is scheduled for the first retransmission scheme, the first device 110 may start or restart an inactivity timer, such as a drx _ inactivity timer in a 3 GPP-based communication system. The inactivity timer indicates a duration after receiving control information from the second device 120 for scheduling a new transmission between the first device 110 and the second device 120. In other words, the inactivity timer may indicate a duration after the PDCCH occasion during which the PDCCH indicates a new UL or DL transmission by the MAC entity.

In general, the received DCI may indicate a DL assignment for a current transmission. According to the DL assignment, the second device sends 315DL data and the first device receives 320DL data.

Based on the retransmission timing indicated in the received timing information, the first device 110 determines timing for monitoring further control information from the second device 120 for scheduling retransmissions of data. For a time interval before the determined timing, the first device 110 may be in an inactive state and not monitor DCI from the second device 120 for power savings. After receiving the DL data at 320, e.g., after the end of the last symbol of the DL data reception, the first device 110 may be in an inactive state for a time interval indicated by "K1". Time interval "K1" may be initiated at the end of DL data reception. As shown in fig. 3, after the indicated timer interval "K1" from the start of the reception of the DL data, the first device 110 starts 325 a retransmission timer for the DL retransmission, such as drx-retransmission timerdl. For example, the retransmission timer may be started in the first symbol after the timing interval K1 indicated in the DCI.

In some example embodiments, prior to starting the retransmission timer, the first device 110 may set the value of an RTT timer for DL (re) transmission (such as drx-HARQ-RTT-TimerDL) to zero and then start the RTT timer (since the value is zero, no time elapses). The first device 110 may alternatively disable the RTT timer before the retransmission timer is to be started.

After the retransmission timer is started, the first device 110 will enter an active state and may monitor and receive further control information for scheduling retransmissions from the second device 120. The first device 110 will remain in the active state until the retransmission timer expires or until additional control information is detected. In the example shown in fig. 3, the second device 120 decides to schedule a retransmission of the DL data for the first device 110 and transmits 330 a further DCI to the first device 110, the DCI indicating the scheduling of the retransmission of the DL data. For example, the DCI may indicate a DL assignment of a current retransmission to be scheduled. The retransmission timer at the first device 110 has not expired and thus the first device 110 successfully monitors and receives 335 the additional DCI.

In some example embodiments, the further DCI may also indicate that the first retransmission scheme is to be applied and also include timing information indicating the timing of the retransmission (such as a retransmission interval denoted "K2"). The retransmission interval "K2" may be the same as or different from the retransmission interval "K1". When transmitting the additional DCI, the second device 120 may determine the retransmission interval "K2" according to various factors as described above.

According to the DL assignment indicated in the further DCI, the second device 120 sends 340 a retransmission of the DL data and the first device 110 receives 345 the retransmission of the DL data. After receiving the retransmission of the DL data, the first device 110 may stop the previously started retransmission timer if the retransmission timer is still running. First device 110 may then enter the inactive state for time interval "K2". After the time interval "K2" has elapsed since the reception of the retransmission of the DL data, the first device 110 restarts the retransmission timer.

UL (re-) transmission in DRX based on dynamic retransmission timing

Fig. 4 illustrates a signaling flow 400 in an UL (re) transmission between the first device 110 and the second device 120 according to some example embodiments of the present disclosure. In the example of fig. 4, the first device 110 operates in DRX mode and the dynamic retransmission timing is controlled by the second device 120.

In signaling flow 400, the second device 120 transmits 405DCI to the first device 110, e.g., via a physical layer DL control channel. The DCI and its transmission may be similar to those discussed above with reference to fig. 2 and 3. The DCI in fig. 3 differs from the DCI in fig. 4 in that in a UL (re) transmission, the DCI includes a UL grant for the first device 110 to transmit its UL data (which may be a new transmission or a retransmission). Retransmission timing such as a retransmission interval indicated in DCI is denoted as "T1".

The DCI for UL (re) transmission may not have a field (such as "PDSCH-to-HARQ feedback timing indicator" indicating a feedback timing indicator) that may be reused for indicating retransmission timing as in the DCI for DL (re) transmission. Accordingly, the timing information may be included in a newly defined field in the DCI. Further, RRC signaling for UL (re) transmissions may not have an IE indicating a timing list for feedback transmissions (such as the IE "dl-DataToUL-ACK") that may be reused to configure a set of candidate values to the first device 110, and thus, a new IE in the RRC signaling may be used to indicate candidate values for retransmission timing.

The first device 110 receives 410 the DCI. The operation of the first device 110 after receiving the DCI may be similar to those discussed above with reference to fig. 2 and 3. According to the UL grant indicated in the DCI, the first device 110 transmits 415UL data and the second device 120 receives 420UL data.

Similar to in DL (re) transmission, the first device 110 may be in an inactive state for a time interval "T1" after transmission of UL data (e.g., after the end of the last symbol of the transmission). As shown in fig. 4, after the indicated time interval "T1" from the end of the UL data transmission by the first device 110, the first device 110 starts 425 a retransmission timer for the UL retransmission, such as a drx-retransmission timerll. For example, the retransmission timer may be started in the first symbol after a timing interval T1 indicated in DCI. The second device 120 transmits 430 additional DCI and the first device 110 receives 435 the additional DCI.

If the additional DCI still indicates the first retransmission scheme to apply (or the additional DCI does not indicate a change to the retransmission scheme) and timing information for the first retransmission scheme, the first device 110 and the second device 120 may perform similar operations as at 415, 420, and 425. Specifically, the first device 110 transmits 440 a retransmission of UL data and the second device 120 receives 445 a retransmission of UL data according to the granted UL indicated in the further DCI. After retransmission of the UL data, the first device 110 restarts 450 the retransmission timer after a timer interval "T2" indicated in another DCI. Other operations at the first device 110 and the second device 120 may be similar to those discussed with reference to fig. 2 and 3.

Examples of DCI loss in DRX based on dynamic retransmission timing

Fig. 5 illustrates a signaling flow 500 in a DL (re) transmission between the first device 110 and the second device 120 according to some example embodiments of the present disclosure. The example of fig. 5 is used to show how DRX is performed in a dynamic retransmission timing based DRX solution in case of DCI loss.

In signaling flow 500, the operation of first device 110 and second device 120 at 505, 510, 515, 520, and 525 is similar to the operation of first device 110 and second device 120 at 305, 310, 315, 320, and 325 in signaling flow 300. In the example of fig. 5, the second device 120 transmits 530 further DCI indicating the first retransmission scheme and further retransmission timing (denoted by "K2"), but the first device 110 fails to receive the further DCI transmitted at 530 to trigger a restart of the new retransmission timer. If the retransmission timer started at 525 is still running, the first device 110 is still active and thus may later receive another DCI (e.g., the DCI sent by the second device 120 at 540) and may restart the retransmission timer again, as shown in the example of fig. 3.

However, if the DCI arrives at the first device 110 after the retransmission timer (started at 525) expires as shown in fig. 5, the first device 110 will not receive the retransmission of the DL data sent 535 by the second device 120 and will not acquire an indication that triggers the start of the retransmission. Thus, even if the second device 120 continues to schedule additional retransmissions and transmits 540 a third DCI indicating the first retransmission scheme and the timing of the third retransmission (represented by "K3"), the first device 110 will lose the detection of the third DCI and the retransmission of the DL data transmitted 545 by the second device 120 that is scheduled in the third DCI. However, even if such an unexpected situation occurs, the performance of the blind retransmission with soft combining is not affected because the first device 110 cannot perform soft combining on subsequent DL data of the blind retransmission because the first device 110 does not receive a transmission of the blind retransmitted DL data at 535 when the additional DCI transmitted at 530 is lost. For this case, the retransmission for reliability may rely on normal HARQ.

DRX based on transmission scheme specific timer configuration

According to some other example embodiments of the present disclosure, to improve the DRX solution in the first retransmission scheme, the second device 120 may specifically configure different timers (or timer values) for different retransmission schemes, and then the first device 110 may select an appropriate timer (or timer value) based on the configured retransmission scheme. Fig. 6 shows a signaling flow 600 for data retransmission according to these example embodiments. For purposes of discussion, signaling flow 600 will be described with reference to fig. 1. The signaling flow 600 may involve the first device 110 and the second device 120 as shown in fig. 1. In some example embodiments, the signaling flow 600 may be particularly beneficial in scenarios where the RTT between the first device 110 and the second device 120 may be relatively large. For example, signaling flow 600 may involve first device 110-1 and second device 120-1 in an NTN network as shown in fig. 1. It should be understood that signaling flow 600 may also be implemented in any other communication network.

In the signaling flow 600, the second device 120 sends 605 a first configuration of a first timer for a first retransmission scheme and the first device 110 receives 610 the first configuration of the first timer for the first retransmission scheme. The second device 120 also sends 615 a second configuration of a second timer for the second retransmission scheme and the first device 110 receives 620 the second configuration of the second timer for the second retransmission scheme. As previously mentioned, the second retransmission scheme is different from the second retransmission scheme. For example, the second retransmission scheme may be a HARQ enabled retransmission scheme requiring feedback, such as a conventional HARQ enabled retransmission scheme, while the first retransmission scheme may be a HARQ disabled retransmission scheme.

According to some example embodiments of the present disclosure, instead of using the same configuration for all retransmission schemes, different configurations may be configured specifically for some timers used in DRX. That is, the first configuration of the first timer may be different from the second configuration of the second timer. In some example embodiments, the first configuration and the second configuration may be sent to the first device 110 via higher layer signaling, such as RRC signaling, for example in a DRX _ Config IE for configuring DRX related parameters. In some example embodiments, a new parameter may be introduced in the DRX _ Config IE to indicate the first configuration (the parameter indicating the second retransmission scheme may already be included in the DRX _ Config IE).

The first device 110 may schedule the same first device 110 with a different (re) transmission scheme as described above. The first device 110 may use the control information to indicate which retransmission scheme to use. In particular, the second device 120 sends 625 control information and the first device 110 receives 630 the control information indicating that the first retransmission scheme is to be applied for transmission of data between the first device 110 and the second device 120. The control information indicating the first transmission scheme may be transmitted in a similar manner as discussed above with reference to fig. 2.

The first configuration or both the first configuration and the second configuration may be used to determine a first value of a first timer used in a first retransmission scheme. In some example embodiments, in accordance with a determination that the first retransmission scheme is to be applied to the transmission of data between the first device and the second device, the first device 110 sets 635 a first value for the first timer based on the first configuration or based on both the first configuration and the second configuration.

The second configuration may indicate a second value of the second timer. The first configuration is used to determine a first value for a first timer. In some example embodiments, the first configuration may indicate the first value directly for the first timer. In this case, the first device 110 may directly set the first value for the first timer based on the first configuration. In some example embodiments, the first configuration may indicate a scaling factor for the first timer. The first device 110 may determine a first value for the first timer based on the scaling factor and the second value. For example, the first value may be determined based on a product of the scaling factor and the second value or based on a sum of the scaling factor and the second value. The first value may be determined based on the scaling factor and the second value in any other way.

According to the example embodiment discussed with reference to fig. 6, the second device 120 may specifically design a timer for the first retransmission scheme that does not require feedback on the transmission, e.g. by extending the timer or shortening another timer in order to balance power consumption and scheduling/transmission flexibility. In addition, by transmitting the first configuration and the second configuration via higher layer signaling instead of physical layer signaling such as DCI, signaling overhead between the first device 110 and the second device 120 may be reduced.

In some example embodiments, the second device 120 may configure an inactivity timer for DRX for the first retransmission scheme and the second retransmission scheme, respectively, via the first configuration and the second configuration. The value of the inactivity timer of the first retransmission scheme may specifically be determined by the first device based on the first configuration or based on both the first configuration and the second configuration. In some other example embodiments, the second device 120 may configure RTT timers for DRX for the first retransmission scheme and the second retransmission scheme, respectively, via the first configuration and the second configuration, and the value of the RTT timer for the first retransmission scheme may be determined specifically by the first device 110 based on the first configuration or based on both the first configuration and the second configuration.

DL and UL (re-) transmissions based on specific inactivity timer configuration

Fig. 7 and 8 illustrate signaling flows 700 and 800 in DL (re) transmission and UL (re) transmission, respectively, where the value of the inactivity timer for the first retransmission scheme is specifically configured, respectively.

In signaling flows 700 and 800, a first configuration of a first timer (i.e., a first inactivity timer) for a first retransmission scheme and a second configuration of a second timer (i.e., a second inactivity timer) for a second retransmission scheme have been sent to the first device 110 by the second device 120. In a 3 GPP-based communication system, the first inactivity timer or the second inactivity timer may also be referred to as a drx _ inactivity timer.

The first value of the first timer indicates a duration after receiving control information from the second device 120 for scheduling a new transmission between the first device 110 and the second device 120 for the first retransmission scheme. The second value of the second timer indicates a duration (referred to as a "second value" for ease of discussion) after receiving control information from the second device 120 for scheduling a new transmission between the first device 110 and the second device 120 for the second retransmission scheme. The second configuration may indicate a second value of the second timer. The first configuration is used to determine a first value for the first timer and may indicate the first value directly or indicate a scaling factor for determining the first timer, as described above.

If the first configuration of the first timer is sent in RRC signaling, a new parameter may be included in the DRX-Config IE to indicate the configuration. The DRX-Config IE that introduces new parameters to indicate the first value of the first timer may be as follows. In this example, a first configuration of an inactivity timer for blind retransmissions and a second configuration of an inactivity timer for HARQ based retransmissions are shown as drx-InactivityTimer _ blinderansmission and drx-InactivityTimer, respectively.

DRX-Config information element

Similarly, the first configuration may indicate a scaling factor, and a new parameter may also be added in the DRX-Config IE to indicate the scaling factor. It should be understood that the first configuration listed in the above IE is for illustrative purposes only and does not represent any limitation on the scope of the present disclosure.

Reference is first made to fig. 7. In operation of DRX, the second device 120 transmits 705DCI and the first device 110 receives 710DCI indicating that the first retransmission scheme is to be applied. However, it should be understood that in some example embodiments, the first retransmission scheme may be configured via other signaling (e.g., RRC). In this example, the DCI indicates a first retransmission scheme to be applied. The DCI may also indicate a new transmission of DL data. Upon receiving the DCI, the first device 110 starts 715 a first timer (i.e., an inactivity timer) with the first value in response to determining that the first retransmission scheme is to be applied. The first timer started here is used to monitor DL (re-) transmissions. The first value of the first timer is determined based on the received first configuration or a combination of the first configuration and the second configuration.

In some example embodiments, the first value may be configured to be greater than the second value. In this way, the first timer is extended and the first device 110 may have an extended duration to remain in an active state. The first device 110 may remain in the active state until the first timer expires. In some example embodiments, where the inactivity timer is specifically configured, an RTT timer, such as drx-HARQ-RTT-TimerDL, will not be started, since the first retransmission scheme does not require feedback on the (re-) transmission. In some example embodiments, a retransmission timer, such as a drx-retransmission timerdl, may not be triggered if no specific configuration is provided for starting the retransmission timer.

As scheduled in the DCI transmitted at 705, the second device 120 transmits 720DL data and the first device 110 receives 725DL data. With the first device 110 remaining in the active state, the second device 120 decides to schedule retransmission of the DL data and sends 730 additional DCI to the first device 110. Since the first timer is still running and the first device 110 is still active, the first device 110 receives 735 DCI. The second device 120 transmits 740 the retransmission of the DL data and the first device 110 receives 745 the retransmission of the DL data as scheduled in the additional DCI transmitted at 730. Thus, the extended value of the first timer allows the first device 110 to receive subsequent DCI and DL data.

In some example embodiments, the first device 110 may remain in an active state to monitor for additional control information until the expiration of a first timer or until additional control information from the second device 120 for scheduling new transmissions is detected. In case further control information for scheduling a new transmission (first transmission of new data) is detected from the second device 120, the first device 110 may restart the further timer (i.e. the further inactivity timer). If the further control information also indicates a first retransmission scheme to be applied for the retransmission of new data, the value of the further timer may be set similarly as discussed above.

Fig. 8 illustrates a signaling flow 800 in an UL (re) transmission between the first device 110 and the second device 120, wherein the value of the inactivity timer for the first retransmission scheme is specifically configured. In the example of fig. 8, the first device 110 operates in DRX mode. In signaling flow 800, operations 805, 810, 815, 820, 825, 830, 835, 840, 845 are similar to operations 705, 710, 715, 720, 725, 730, 735, 740, 745 in signaling flow 700. The difference is that at 820, 825 and 840, 845, the first device 110 starts a first timer for UL (re) transmission and the first device 110 transmits UL data for reception by the second device 120.

DL and UL (re-) transmissions based on specific RTT timer configuration

Fig. 9 and 10 illustrate signaling flows 900 and 1000 in DL (re) transmission and UL (re) transmission, respectively, in which the value of the RTT timer for the first retransmission scheme is specifically configured.

In signaling flows 900 and 1000, a first configuration of a first timer (i.e., a first RTT timer) for a first retransmission scheme and a second configuration of a second timer (i.e., a second RTT timer) for a second retransmission scheme have been sent to the first device 110 by the second device 120. In 3GPP based communication systems, the first RTT Timer or the second RTT Timer may also be referred to as drx-HARQ-RTT-Timer, more specifically, as drx-HARQ-RTT-TimerDL for DL (re) transmission or drx-HARQ-RTT-timerll for UL (re) transmission.

In DL (re) transmission, the first value of the first timer indicates a minimum duration for the first retransmission scheme before a DL assignment for retransmission is expected; similarly, the second value of the second timer indicates a minimum duration for the second retransmission scheme before a DL assignment for retransmission is expected. In UL (re) transmission, the first value of the first timer indicates a minimum duration for the first retransmission scheme before a UL grant for retransmission is expected; similarly, the second value of the second timer indicates a minimum duration for the second retransmission scheme that is expected before the UL grant for the retransmission.

The first configuration of RTT timers may be sent in RRC signaling and new parameters may be included in the DRX-Config IE to indicate the configuration. In a similar manner for the configuration of the inactivity timer, the DRX-Config IE introduces a new parameter to indicate the first value or scaling factor of the first timer, as described above.

In example embodiments where the RTT timer for the first retransmission scheme is specifically configured, other DRX timers, such as inactivity timers and retransmission timers, may also be enabled during DRX. The RTT timer is optimized compared to the second transmission scheme.

In the signaling flow 900, the second device 120 transmits 905 control signaling (e.g., DCI) and the first device 110 receives 910 the control signaling indicating that the first retransmission scheme is to be applied. The DCI indicates a first retransmission scheme to be applied. In some example embodiments, the DCI may also indicate that a new transmission of new data is scheduled for the first retransmission scheme, and the first device 110 may start or restart an inactivity timer, such as a drx _ inactivity timer in a 3 GPP-based communication system. According to the DL assignment indicated in the DCI, the second device 120 transmits 915DL data and the first device 110 receives 920DL data.

After receiving the DL data, the first device 110 starts 925 a first timer, i.e. an RTT timer for DL (re) transmissions. In some example embodiments, the first value may be configured to be less than the second value. The first device 110 is not forced to be in an active state, such as during an RTT timer. Whether the first device 110 is in an active state during the RTT timer running may also depend on whether other timers still require the first device 110 to remain in an active state. By configuring the RTT timer to a smaller value, the first device 110 may have a higher probability of successfully monitoring and receiving additional DCI from the second device 120. The first timer started here is used to monitor DL (re-) transmissions. The first value of the first timer is determined based on the received first configuration or a combination of the first configuration and the second configuration.

After receiving the DL data, the first device 110 may further stop a retransmission timer (such as drx-retransmission timerdl), if any. Depending on the first value, the first timer (i.e., the RTT timer) expires 930. In some example embodiments, the first device 110 may restart a retransmission timer (such as drx-retransmission timerdl) after the RTT timer expires. The first device 110 may then be in an active state and receive 940 further DCI sent 935 from the second device 120. The further DCI also indicates the first retransmission scheme. Thus, after the first device receives 950 a retransmission of the DL data sent 945 from the second device 120, the second device 120 restarts 955 the RTT timer.

Fig. 10 illustrates a signaling flow 1000 in UL (re) transmission between the first device 110 and the second device 120, wherein the value of the RTT timer for the first retransmission scheme is specifically configured. In the example of fig. 10, the first device 110 operates in DRX mode. In signaling flow 1000, operations 1005, 1010, 1015, 1020, 1025, 1030, 1035, 1040, 1045 are similar to operations 905, 910, 915, 920, 925, 930, 935, 940, 945 in signaling flow 900. Except that first device 110 transmits UL data for reception by second device 120 and first device 110 starts a first timer (such as drx-HARQ-RTT-timerll) for UL (re) transmission at 1015, 1020, 1025 and 1045, 1050 and 1055.

Example methods implemented at respective devices

Fig. 11 illustrates a flowchart of an example method 1100 implemented at a first device, according to some example embodiments of the present disclosure. For discussion purposes, the method 1100 will be described with reference to fig. 1 from the perspective of the first device 110.

At block 1110, the first device 110 receives control information from the second device 120, the control information indicating a first retransmission scheme to be applied for transmission of data between the first device 110 and the second device 120, the first retransmission scheme requiring retransmission of the data to be performed independently of feedback on previous transmissions of the data. At block 1120, the first device 110 receives timing information specific to the first retransmission scheme from the second device 120, the timing information indicating retransmission timing. At block 1130, the first device 110 determines a timing for monitoring further control information from the second device 120 for scheduling retransmissions based on the retransmission timing.

The method 1100 proposes a DRX configuration for blind retransmissions with dynamic timing for entering an active state. With this solution, the second device 120 can flexibly schedule retransmissions and the first device 110 can not only receive control information in time, but can also optimize power saving by indicating possible retransmission timing from the second device 120.

In some example embodiments, the timing information received at block 1120 may indicate a time interval at which the first device may be in an inactive state, and at block 1130, the first device 110 may determine to start a retransmission timer at the end of the time interval and enter an active state. The retransmission timer indicates a maximum duration until either a DL retransmission or an UL grant for an UL retransmission is received. After the first retransmission timer is started, the first device 110 may remain in an active state for monitoring for additional control information until the retransmission timer expires or until additional control information is detected.

In some example embodiments, the first device 110 may set the value of the RTT timer to zero according to the reception of the control information indicating the first retransmission scheme to be applied. Alternatively, the first device 110 may disable the RTT timer upon receipt of control information indicating the first retransmission scheme to be applied. The RTT timer indicates a minimum duration before a DL assignment or UL grant is expected for HARQ based retransmissions.

In some example embodiments, the timing information may be received via a physical layer DL control channel. For example, to receive timing information, the first device 110 may detect a field of a physical layer DL control channel. This field may be a field indicating a feedback timing indicator if the second retransmission scheme is configured, and timing information if the first retransmission scheme is configured. In this way, existing fields in the control information can be reused when the first retransmission scheme is configured, since no feedback timing indicator is needed in the first retransmission scheme. Alternatively, a dedicated new field may be defined in the control information to indicate only timing information for the first retransmission scheme.

In some embodiments, if the second retransmission scheme is configured, a set of candidate values indicating a timing list for transmission of feedback may be sent to the first device, which may simplify the required configuration parameters. In some example embodiments, the first device 110 may receive a set of candidate values for retransmission timing for the first retransmission scheme from the second device 120 via higher layer signaling. In some embodiments, the set of candidate values for retransmission timing for the first retransmission scheme may be carried to the first device by reusing signaling for a timing list indicating transmission of feedback for the second retransmission scheme. The timing information received at block 1120 may indicate one of the candidate values, e.g., via a physical layer downlink control channel.

Fig. 12 illustrates a flowchart of an example method 1200 implemented at a first device, according to some example embodiments of the present disclosure. For discussion purposes, the method 1200 will be described with reference to fig. 1 from the perspective of the first device 110.

At block 1210, the first device 110 receives a first configuration of a first timer for a first retransmission scheme from the second device 120. At block 1220, the first device 110 receives, from the second device 120, a second configuration of a second timer for a second retransmission scheme different from the first retransmission scheme. In block 1230, the first device 110 sets a first value for the first timer based on the first configuration or both the first configuration and the second configuration in accordance with a determination that the first retransmission scheme is to be applied to the transmission of data between the first device 110 and the second device 120. The first retransmission scheme may require that the retransmission of the data is performed independently of feedback on previous transmissions of the data.

The method also presents a solution for DRX supporting blind retransmissions based on retransmission scheme specific timer configuration. With this solution, the first device 110 may select an appropriate timer specific to the retransmission scheme (which may be an extended timer (such as an inactivity timer) or a shortened timer (such as an RTT timer)) based only on the configuration of the retransmission scheme (e.g., a blind retransmission scheme) in order to achieve power savings.

In some example embodiments, the first value of the first timer may indicate a duration after receiving control information from the second device 120 for scheduling a new transmission between the first device 110 and the second device 120 for the first retransmission scheme; that is, the first timer is an inactivity timer for the first retransmission scheme. The second timer may indicate a duration after receiving control information from the second device 120 for scheduling a new transmission between the first device 110 and the second device 120 for the second retransmission scheme; that is, the second timer is an inactive timer for the second retransmission scheme. In these example embodiments, the first device 110 may start a first timer after receiving the control information and then remain in an active state until the first timer expires or until additional control information from the second device for scheduling a new transmission is detected.

In some example embodiments, the first timer may indicate a minimum duration for the first retransmission scheme before a DL assignment or UL grant for retransmission is expected; that is, the first timer is an RTT timer for the first retransmission scheme. The second timer may indicate a minimum duration for the second retransmission scheme before a DL assignment or UL grant for retransmission is expected; that is, the first timer is an RTT timer for the second retransmission scheme. If a DL (re-) transmission is performed, the first device 110 may start a first timer after receiving a transmission of data from the second device 120. In case UL (re) transmission is performed, the first device 110 may start a first timer after transmission of data to the second device 120.

In some example embodiments, in accordance with a determination that the first configuration indicates a first value for the first timer, the first device 110 may set the first value directly for the first timer based on the first configuration. In accordance with a determination that the first configuration indicates a scaling factor for the first timer and the second configuration indicates a second value for the second timer, the first device 110 may set the first value for the first timer based on the scaling factor and the second value for the second retransmission scheme, e.g., by determining the first value based on a product thereof or a sum thereof.

Fig. 13 illustrates a flowchart of an example method 1300 implemented at a second device, according to some example embodiments of the present disclosure. For purposes of discussion, the method 1300 will be described with reference to fig. 1 from the perspective of the second device 120.

At block 1310, the second device 120 sends control information to the first device 110, the control information indicating a first retransmission scheme to be applied for transmission of data between the first device 110 and the second device 120. The first retransmission scheme requires that the retransmission of the data is performed independently of feedback on previous transmissions of the data. At block 1320, the second device 120 sends timing information specific to the first retransmission scheme to the first device 110. The timing information indicates a retransmission timing to configure timing for the first device 110 to enter an active state to monitor further control information from the second device 120 for scheduling retransmissions. In some example embodiments, the second device 120 may transmit the timing information via a physical layer DL control channel.

In some example embodiments, the retransmission timing may comprise a time interval at which the first device 110 is in an inactive state and the end of which triggers the start of a retransmission timer at the first device 110. The retransmission timer may indicate a maximum duration of the UL grant until the first device 110 receives a DL retransmission or a UL retransmission.

Fig. 14 illustrates a flowchart of an example method 1400 implemented at a second device, according to some example embodiments of the present disclosure. For discussion purposes, the method 1400 will be described with reference to fig. 1 from the perspective of the second device 120.

At block 1410, the second device 120 sends a first configuration of a first timer of the first device 110 for a first retransmission scheme to the first device 110. At block 1420, the second device 120 sends, to the first device 110, a second configuration of a second timer of the first device 110 for a second retransmission scheme different from the first retransmission scheme. At block 1430, the second device 120 sends control information to the first device 110. The control information indicates that the first retransmission scheme is to be applied for transmission of data between the first device 110 and the second device 120.

The first configuration or a combination of the first configuration and the second configuration may be used by the first device 110 to calculate a first value for a first timer of a first retransmission scheme. By sending a different first configuration and/or a different second configuration to the first device 110, the second device 120 may control the value of the first timer for the first retransmission scheme. In general, the first device 110 and the second device 120 may apply the same method to determine the first value of the first timer based on the first configuration or a combination of the first configuration and the second configuration.

In some example embodiments, the first configuration indicates a first value of the first timer. In some example embodiments, the first configuration indicates a scaling factor of the first timer and the second configuration indicates a second value of the second timer. In this case, the first value may be determined based on the scaling factor and the second value.

Example apparatus

In some example embodiments, a first apparatus (e.g., first device 110) capable of performing any of method 1100 may include means for performing the respective operations of method 1100. The component may be implemented in any suitable form. For example, the components may be implemented in circuitry or software modules. The first apparatus may be implemented as the first device 110 or included in the first device 110.

In some example embodiments, the first apparatus comprises means for: receiving, from a second apparatus, control information indicating a first retransmission scheme to be applied for transmission of data between the first apparatus and the second apparatus, the first retransmission scheme requiring retransmission of the data to be performed independently of feedback on previous transmissions of the data; receiving timing information specific to a first retransmission scheme from a second apparatus, the timing information indicating retransmission timing; and determining a timing for monitoring further control information from the second apparatus for scheduling retransmissions based on the retransmission timing.

In some example embodiments, the retransmission timing comprises a time interval in which the first apparatus may be in an inactive state, and the means for determining the timing comprises means for: determining to start a retransmission timer after the end of the time interval and entering an active state, the retransmission timer indicating a maximum duration until a downlink retransmission or an uplink grant for an uplink retransmission is received; and remain in an active state to monitor for additional control information until the retransmission timer expires or until additional control information is detected.

In some example embodiments, the first apparatus further comprises means for setting a value of the round trip time timer to zero in dependence on the reception of the control information indicating the first retransmission scheme to be applied, or means for disabling the round trip time timer in dependence on the reception of the control information indicating the first retransmission scheme to be applied. The round trip time timer indicates a minimum duration before a downlink assignment or uplink grant is expected for a hybrid automatic repeat request based retransmission.

In some example embodiments, the means for receiving timing information comprises means for receiving timing information via a physical layer downlink control channel.

In some example embodiments, the means for receiving timing information comprises means for detecting a field of a physical layer downlink control channel. In case the second retransmission scheme is configured, then the field may indicate a feedback timing indicator, and in case the first retransmission scheme is configured, then the field may indicate timing information. That is, the field may have different meanings for different retransmission schemes. Alternatively, this field may be dedicated to indicating timing information of the first retransmission scheme.

In some example embodiments, the control information may implicitly or explicitly indicate a retransmission scheme. For example, the control information may include an indication to enable/disable hybrid automatic repeat request feedback and/or an indication for a retransmission scheme indicating the first retransmission scheme.

In some example embodiments, the first apparatus further comprises means for receiving a set of candidate values for retransmission timing for the first retransmission scheme from the second apparatus via higher layer signaling. The means for receiving timing information comprises means for receiving timing information indicating one of the candidate values via a physical layer downlink control channel.

In some example embodiments, the set of candidate values received by the first apparatus may instead indicate a timing list for transmitting feedback if the second retransmission scheme is configured.

In some example embodiments, the first apparatus further comprises means for performing other operations in some example embodiments of the method 1100. In some example embodiments, the component comprises 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 performance of the first apparatus.

In some example embodiments, a first apparatus (e.g., first device 110) capable of performing any of method 1200 may include means for performing the respective operations of method 1200. The component may be implemented in any suitable form. For example, the components may be implemented in circuitry or software modules. The first apparatus may be implemented as the first device 110 or included in the first device 110.

In some example embodiments, the first apparatus comprises means for: receiving, from a second apparatus, a first configuration of a first timer for a first retransmission scheme; receiving, from a second apparatus, a second configuration of a second timer for a second retransmission scheme different from the first retransmission scheme; and in accordance with a determination that the first retransmission scheme is to be applied to transmission of data between the first apparatus and the second apparatus, setting a first value for the first timer based on the first configuration or both the first configuration and the second configuration.

In some example embodiments, the first retransmission scheme requires that the retransmission of the data be performed independently of feedback on previous transmissions of the data.

In some example embodiments, the first value of the first timer indicates a duration after receiving control information from the second apparatus, the control information being used to schedule a new transmission between the first apparatus and the second apparatus for the first retransmission scheme, and the second timer indicates a duration of the second retransmission scheme. The first apparatus further comprises means for: the first timer is started after receiving the control information and remains in an active state until the first timer expires or until further control information from the second device for scheduling a new transmission is detected.

In some example embodiments, the first timer indicates a minimum duration for the first retransmission scheme before a downlink assignment or uplink grant for retransmission is expected, and the second timer indicates a minimum duration for the second retransmission scheme. The first apparatus further comprises means for starting a first timer after receiving the transmission of data from the second apparatus; or means for starting the first timer after transmission of the data to the second device.

In some example embodiments, the means for setting the first value for the first timer comprises means for: in accordance with a determination that the first configuration indicates a first value for a first timer, setting the first value for the first timer; and in accordance with a determination that the first configuration indicates a scaling factor for the first timer and the second configuration indicates a second value for the second timer, setting a first value for the first timer based on the scaling factor and the second value.

In some example embodiments, the first apparatus further comprises means for performing other steps of the method 1200 in some example embodiments. In some example embodiments, the component comprises 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 performance of the first apparatus.

In some example embodiments, a second apparatus (e.g., second device 120) capable of performing any of method 1300 may include means for performing the respective operations of method 1300. The component may be implemented in any suitable form. For example, the components may be implemented in circuitry or software modules. The second apparatus may be implemented as the second device 120 or included in the second device 120.

In some example embodiments, the second apparatus comprises means for: transmitting, to the first apparatus, control information indicating a first retransmission scheme to be applied for transmission of data between the first apparatus and the second apparatus, the first retransmission scheme requiring retransmission of the data to be performed independently of feedback on previous transmissions of the data; and transmitting, to the first apparatus, timing information specific to the first retransmission scheme, the timing information indicating retransmission timing for monitoring, for the first apparatus, further control information configuration timing from the second apparatus for scheduling retransmissions.

In some example embodiments, the retransmission timing comprises a time interval at which the first apparatus is in an inactive state and the end of which triggers the start of a retransmission timer at the first apparatus, the retransmission timer indicating a maximum duration of uplink grants until the first apparatus receives a downlink retransmission or an uplink retransmission.

In some example embodiments, the means for transmitting the timing information comprises means for transmitting the timing information via a physical layer downlink control channel.

In some example embodiments, the second apparatus also includes means for performing other operations of method 1300 in some example embodiments. In some example embodiments, the component comprises 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 performance of the second apparatus.

In some example embodiments, a second apparatus (e.g., second device 120) capable of performing any of the methods 1400 may include means for performing the respective operations of the methods 1400. The component may be implemented in any suitable form. For example, the components may be implemented in circuitry or software modules. The second apparatus may be implemented as the second device 120 or included in the second device 120.

In some example embodiments, the second apparatus comprises means for: transmitting, to a first apparatus, a first configuration of a first timer of the first apparatus for a first retransmission scheme; transmitting, to the first apparatus, a second configuration of a second timer of the first apparatus for a second retransmission scheme different from the first retransmission scheme; and means for transmitting, to the first apparatus, control information indicating that the first retransmission scheme is to be applied to transmission of data between the first apparatus and the second apparatus, wherein the first configuration or a combination of the first configuration and the second configuration determines a first value of the first timer.

In some example embodiments, the first configuration indicates a first value of the first timer. In some example embodiments, the first configuration indicates a scaling factor for the first timer, the second configuration indicates a second value for the second timer, and the first value is determined based on the scaling factor and the second value.

In some example embodiments, the second apparatus also includes means for performing other operations of the method 1400 in some example embodiments. In some example embodiments, the component comprises 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 performance of the second apparatus.

Example apparatus and computer-readable Medium

Fig. 15 is a simplified block diagram of an apparatus 1500 suitable for implementing example embodiments of the present disclosure. Device 1500 may be provided to implement a communication device, such as first device 110 or second device 120 as shown in fig. 1. As shown, the device 1500 includes one or more processors 1510, one or more memories 1520 coupled to the processors 1510, and one or more communication modules 1540 coupled to the processors 1510.

The communications module 1540 provides for two-way communications. The communication module 1540 has at least one antenna to facilitate communications. A communication interface may represent any interface necessary to communicate with other network elements.

The processor 1510 may be of any type suitable for a local technology network, and may include, as non-limiting examples, one or more of the following: general purpose computers, special purpose computers, microprocessors, Digital Signal Processors (DSPs) and processors based on a multi-core processor architecture. Device 1500 may have multiple processors, such as application specific integrated circuit chips that are time dependent from a clock synchronized to the main processor.

The memory 1520 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memory include, but are not limited to, Read Only Memory (ROM)1524, Electrically Programmable Read Only Memory (EPROM), flash memory, a hard disk, a Compact Disk (CD), a Digital Video Disk (DVD), and other magnetic and/or optical storage. Examples of volatile memory include, but are not limited to, Random Access Memory (RAM)1522 and other volatile memory that does not persist during a power down period.

The computer programs 1530 include computer-executable instructions that are executed by the associated processor 1510. The program 1530 may be stored in a memory (e.g., ROM 1524). Processor 1510 can perform any suitable actions and processes by loading program 1530 into RAM 1522.

Example embodiments of the present disclosure may be implemented by way of program 1530 such that device 1500 may perform any of the processes of the present disclosure as discussed with reference to fig. 2-14. Example embodiments of the present disclosure may also be implemented by hardware or a combination of software and hardware.

In some example embodiments, the program 1530 may be tangibly embodied in a computer-readable medium, which may be included in the device 1500 (such as in the memory 1520) or in other storage accessible to the device 1500. The device 1500 can load the program 1530 from the computer-readable medium into the RAM 1522 for execution. The computer readable medium may include any type of tangible, non-volatile memory, such as ROM, EPROM, flash memory, a hard disk, a CD, a DVD, etc. Fig. 16 shows an example of a computer readable medium 1600 in the form of a CD or DVD. The computer readable medium has a program 1530 stored thereon.

In general, the various embodiments of the disclosure may be implemented using hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented using hardware, while other aspects may be implemented using firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of the embodiments of the disclosure are illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that the blocks, apparatus, systems, techniques or methods 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 comprises computer executable instructions, such as instructions comprised in program modules, that are executed in a device on a target real or virtual processor to perform any of the methods as described above with reference to fig. 1 to 14. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various embodiments, the functionality of the program modules may be combined or split between program modules as desired. Machine-executable instructions of program modules may be executed within local or distributed devices. In a distributed facility, program modules may be located in both local and remote memory storage media.

Program code for performing the 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 flowchart and/or block diagram to be performed. The program code may execute entirely on the 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, computer program code or related data may be carried by any suitable carrier to enable a device, apparatus or processor to perform various processes and operations as described above. Examples of a 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 is 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 a 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 described 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 some cases, multitasking and parallel processing may be advantageous. Also, while several specific implementation details are included in the above discussion, these should not be construed as limitations on the scope of the 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 can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination.

Although the disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the 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 (29)

1. A first device, comprising:

at least one processor; and

at least one memory including computer program code;

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

receiving control information from a second device, the control information indicating a first retransmission scheme to be applied to a transmission of data between the first device and the second device, the first retransmission scheme requiring retransmission of the data to be performed independently of feedback on previous transmissions of the data;

receiving timing information specific to the first retransmission scheme from the second device, the timing information indicating retransmission timing; and

determining a timing for monitoring further control information from the second device for scheduling the retransmission based on the retransmission timing.

2. The apparatus of claim 1, wherein the retransmission timing comprises a time interval during which the first apparatus is in an inactive state, and wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the first apparatus to determine the timing by:

determining to start a retransmission timer after the time interval ends and entering an active state, the retransmission timer indicating a maximum duration until a downlink retransmission or an uplink grant for an uplink retransmission is received; and

remaining in the active state for monitoring the further control information until the retransmission timer expires or until the further control information is detected.

3. The apparatus of claim 1 or 2, wherein the at least one memory and the computer program code are configured to, with the at least one processor, further cause the first apparatus to:

in accordance with a reception of the control information indicating the first retransmission scheme to be applied,

setting the value of the round trip time timer to zero, or

The round-trip-time timer is disabled and,

wherein the round trip time timer indicates a minimum duration before a downlink assignment or uplink grant for hybrid automatic repeat request based retransmission is expected.

4. The apparatus of any of claims 1-3, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the first apparatus to receive the timing information by:

receiving the timing information via a physical layer downlink control channel.

5. The apparatus of claim 4, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the first apparatus to receive the timing information by:

detecting a field of the physical layer downlink control channel, the field indicating a feedback timing indicator if a second retransmission scheme is configured and the timing information if the first retransmission scheme is configured, or the field indicating only the timing information for the first retransmission scheme.

6. The apparatus according to any of claims 1 to 5, wherein the control information comprises an indication for enabling/disabling hybrid automatic repeat request feedback and/or an indication for a retransmission scheme to indicate the first retransmission scheme.

7. The apparatus of any of claims 1-6, wherein the at least one memory and the computer program code configured to, with the at least one processor, further cause the first apparatus to:

receiving a set of candidate values for retransmission timing of the first retransmission scheme from the second device via higher layer signaling, an

Wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the first apparatus to receive the timing information by:

receiving the timing information indicating one of the candidate values via a physical layer downlink control channel.

8. The apparatus of claim 7, wherein the set of candidate values indicates a timing list for transmitting feedback if a second retransmission scheme is configured.

9. A first device, comprising:

at least one processor; and

at least one memory including computer program code;

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

receiving, from a second device, a first configuration of a first timer for a first retransmission scheme;

receiving, from the second device, a second configuration of a second timer for a second retransmission scheme different from the first retransmission scheme; and

in accordance with a determination that the first retransmission scheme is to be applied to transmissions of data between the first device and the second device, setting a first value for the first timer based on the first configuration or both the first configuration and the second configuration.

10. The apparatus of claim 9, wherein the first retransmission scheme requires retransmission of the data to be performed independently of feedback on previous transmissions of the data.

11. The apparatus according to claim 9 or 10, wherein the first value of the first timer indicates a duration after receiving control information from the second apparatus, the control information being used to schedule a new transmission between the first apparatus and the second apparatus for the first retransmission scheme, and the second timer indicates the duration of the second retransmission scheme; and is

Wherein the at least one memory and the computer program code are configured to, with the at least one processor, further cause the first apparatus to:

starting the first timer after receiving the control information, an

Remain in an active state until the expiration of the first timer or until additional control information from the second device for scheduling a new transmission is detected.

12. The apparatus according to claim 9 or claim 10, wherein the first timer indicates a minimum duration for the first retransmission scheme before a downlink assignment or an uplink grant for retransmission is expected, and the second timer indicates the minimum duration for the second retransmission scheme, and

wherein the at least one memory and the computer program code are configured to, with the at least one processor, further cause the first apparatus to:

starting the first timer after receiving the transmission of the data from the second device; or alternatively

Starting the first timer after transmission of the data to the second device.

13. The apparatus of any of claims 9 to 12, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the second apparatus to set the first value for the first timer by:

in accordance with a determination that the first configuration indicates the first value for the first timer, setting the first value for the first timer; and

in accordance with a determination that the first configuration indicates a scaling factor for the first timer and the second configuration indicates a second value for the second timer, setting the first value for the first timer based on the scaling factor and the second value.

14. A second device, comprising:

at least one processor; and

at least one memory including computer program code;

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

sending control information to a first device, the control information indicating a first retransmission scheme to be applied to a transmission of data between the first device and the second device, the first retransmission scheme requiring retransmission of the data to be performed independently of feedback on previous transmissions of the data; and

transmitting timing information specific to the first retransmission scheme to the first device, the timing information indicating retransmission timing to monitor further control information configuration timing for the first device from the second device for scheduling the retransmission.

15. The apparatus of claim 14, wherein the retransmission timing comprises a time interval during which the first apparatus is in an inactive state and an end of the time interval triggers a start of a retransmission timer at the first apparatus that indicates a maximum duration of time received by the first apparatus until a downlink retransmission or an uplink grant for an uplink retransmission.

16. The apparatus of claim 14 or 15, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the second apparatus to transmit the timing information via a physical layer downlink control channel.

17. A second device, comprising:

at least one processor; and

at least one memory including computer program code;

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

transmitting, to a first device, a first configuration of a first timer of the first device for a first retransmission scheme;

transmitting, to the first device, a second configuration of a second timer of the first device for a second retransmission scheme different from the first retransmission scheme; and

sending control information to the first device, the control information indicating that the first retransmission scheme is to be applied for transmission of data between the first device and the second device, wherein the first configuration or a combination of the first configuration and the second configuration determines a first value for the first timer.

18. The apparatus of claim 17, wherein the first configuration indicates the first value for the first timer, or

Wherein the first configuration indicates a scaling factor for the first timer, the second configuration indicates a second value for the second timer, and the first value is determined based on the scaling factor and the second value.

19. A method, comprising:

receiving, at a first device and from a second device, control information indicating a first retransmission scheme to be applied for transmission of data between the first device and the second device, the first retransmission scheme requiring retransmission of the data to be performed independently of feedback on previous transmissions of the data;

receiving timing information specific to the first retransmission scheme from the second device, the timing information indicating retransmission timing; and

determining a timing for monitoring further control information from the second device for scheduling the retransmission based on the retransmission timing.

20. The method of claim 19, wherein the retransmission timing comprises a time interval during which the first device is in an inactive state, and wherein determining the timing comprises:

determining to start a retransmission timer after the time interval ends and entering an active state, the retransmission timer indicating a maximum duration until a downlink retransmission or an uplink grant for an uplink retransmission is received; and

remaining in the active state for monitoring the further control information until the retransmission timer expires or until the further control information is detected.

21. The method of claim 19 or 20, wherein receiving the timing information comprises:

receiving the timing information via a physical layer downlink control channel.

22. A method, comprising:

receiving, at a first device and from a second device, a first configuration of a first timer for a first retransmission scheme;

receiving, from the second device, a second configuration of a second timer for a second retransmission scheme different from the first retransmission scheme; and

in accordance with a determination that the first retransmission scheme is to be applied to transmissions of data between the first device and the second device, setting a first value for the first timer based on the first configuration or both the first configuration and the second configuration.

23. A method, comprising:

transmitting, at a second device and to a first device, control information indicating a first retransmission scheme to be applied for transmission of data between the first device and the second device, the first retransmission scheme requiring retransmission of the data to be performed independently of feedback on previous transmissions of the data; and

transmitting, to the first device via a physical layer downlink control channel, timing information specific to the first retransmission scheme, the timing information indicating retransmission timing to monitor, for the first device, further control information configuration timing from the second device for scheduling the retransmission.

24. A method, comprising:

transmitting, at a second device and to a first device, a first configuration of a first timer of the first device for a first retransmission scheme;

transmitting, to the first device, a second configuration of a second timer of the first device for a second retransmission scheme different from the first retransmission scheme; and

sending control information to the first device, the control information indicating that the first retransmission scheme is to be applied for transmission of data between the first device and the second device, wherein the first configuration or a combination of the first configuration and the second configuration determines a first value for the first timer.

25. A first apparatus comprising means for:

receiving control information from a second apparatus, the control information indicating a first retransmission scheme to be applied to a transmission of data between the first apparatus and the second apparatus, the first retransmission scheme requiring retransmission of the data to be performed independently of feedback on previous transmissions of the data;

receiving timing information specific to the first retransmission scheme from the second apparatus, the timing information indicating retransmission timing; and

determining a timing for monitoring further control information from the second apparatus for scheduling the retransmission based on the retransmission timing.

26. A first apparatus comprising means for:

receiving, from a second apparatus, a first configuration of a first timer for a first retransmission scheme;

receiving, from the second apparatus, a second configuration of a second timer for a second retransmission scheme different from the first retransmission scheme; and

in accordance with a determination that the first retransmission scheme is to be applied to transmissions of data between the first apparatus and the second apparatus, setting a first value for the first timer based on the first configuration or both the first configuration and the second configuration.

27. A second apparatus comprising means for:

sending control information to a first apparatus, the control information indicating a first retransmission scheme to be applied to a transmission of data between the first apparatus and the second apparatus, the first retransmission scheme requiring retransmission of the data to be performed independently of feedback on previous transmissions of the data; and

transmitting, to the first device via a physical layer downlink control channel, timing information specific to the first retransmission scheme, the timing information indicating retransmission timing to monitor, for the first device, further control information configuration timing from the second device for scheduling the retransmission.

28. A second apparatus comprising means for:

transmitting, to a first apparatus, a first configuration of a first timer of the first apparatus for a first retransmission scheme;

transmitting, to the first apparatus, a second configuration of a second timer of the first apparatus for a second retransmission scheme different from the first retransmission scheme; and

sending control information to the first apparatus, the control information indicating that the first retransmission scheme is to be applied for transmission of data between the first apparatus and the second apparatus, wherein the first configuration or a combination of the first configuration and the second configuration determines a first value for the first timer.

29. A computer readable medium comprising program instructions for causing an apparatus to perform at least the method of claims 19 to 21, the method of claim 22, the method of claim 23 or the method of claim 24.

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