Application aware adaptive radio link control layer retransmission enhancements

Abstract

Application Aware Adaptive Radio Link Control Layer Retransmission Enhancements Proposed is a User Equipment, UE, configured to support an Automatic Repeat Request, ARQ, process when communicating with a network node of a radio access network in accordance with configuration information; wherein the configuration information includes a plurality of Radio Link Control, RLC, parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate, the UE comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the UE at least to: receive, from the network node, one or more data units of a data unit set using the first set of RLC parameters; and in response to a determination, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the received one or more data units of the data unit set meets the predetermined threshold, receive, from the network node, one or more remaining data units of the data unit set using the second set of RLC parameters

Description

APPLICATION AWARE ADAPTIVE RADIO LINK CONTROL LAYER RETRANSMISSION ENHANCEMENTSTECHNOLOGY

[0001] Various example embodiments relate to radio transmissions and, in particular, to Radio Link Control (RLC) (re-)transmission related enhancements in Radio Access Networks (RANs).BACKGROUND

[0002] Any discussion of the background art throughout the specification should in no way be considered as an admission that such art is widely known or forms part of common general knowledge in the field.

[0003] Radio Link Control (RLC) plays an important role in modem wireless networks such as UMTS, LTE, and 5G networks, as it manages the reliability and flow control of data transmissions between the User Equipment (UE) (e.g., mobile devices, computers, etc.) and the eNodeB (e.g., base stations) to ensure that data is delivered correctly and efficiently over the radio link. RLC operates at Layer 2 (Data Link Layer) within the Radio Access Network (RAN) between the Radio Resource Control (RRC) layer and the Medium Access Control (MAC) layer in the protocol stack for wireless networks. In practice, RLC can divide data from higher layers into smaller data units (e.g., Protocol Data Units (PDUs)) for transmission, and further reassemble received data units back into the original data units. Besides, RLC can also perform error corrections using Automatic Repeat Request (ARQ) processes.

[0004] In some circumstances there is a need for enhancing RLC (re-)transmissions in wireless networks with improved efficiency without sacrificing reliability. In particular, it may be desirable to increase the reliability of data transmissions by enabling faster triggering of RLC retransmissions and, at the same time, to improve its efficiency. However, the existing technique / approach has encountered challenges in satisfying both of these enhancements.SUMMARY

[0005] In accordance with a first aspect of the present disclosure, there is provided a User Equipment (UE) configured to support an Automatic Repeat Request (ARQ) process when communicating with a network node of a radio access network in accordance with configuration information. In particular, the configuration information includes a plurality of Radio LinkControl (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate, the UE comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the UE at least to: receive, from the network node, one or more data units of a data unit set using the first set of RLC parameters; and in response to a determination, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the received one or more data units of the data unit set meets the predetermined threshold, receive, from the network node, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0006] In some examples, the first set of RLC parameters defines a first retransmission policy enabling the first retransmission rate and the second set of RLC parameters defines a second retransmission policy enabling the second retransmission rate. Moreover, the UE is further caused to select the second retransmission policy for receiving the one or more remaining data units of the data unit set in response to the determination.

[0007] In some examples, the predetermined threshold to be met comprises a required amount of data to be received by the UE for successfully decoding the data unit set, and the determination comprises determining that a received amount of data which has been received by the UE fulfills the required amount of data. Optionally, the received amount of data which has been received by the UE comprises at least one of the following: a certain number or percentage of data units within the data unit set, a certain number of bytes within the data unit set, or a certain percentage value of total size of the data unit set.

[0008] In some examples, the UE is further caused to receive, from the network node, a configuration message including the configuration information for controlling a radio link between the UE and the network node. Optionally, the plurality of RLC parameters comprises at least one of the following: a maximum number of retransmissions, a preconfigured time for triggering a retransmission, a T-reassembly timer, a T-PollRetransmit timer, a T-StatusProhibit timer, or a probability for triggering a blind retransmission.

[0009] In some examples:for defining the second retransmission policy, the second set of RLC parameters is set based on one or more of the following: increasing a duration of one or more of the T-reassembly timer, the T-PollRetransmit timer, and the T-StatusProhibit timer, reducing the maximum number of retransmissions, disabling the preconfigured time for triggering a retransmission and / or the probability for triggering a blind retransmission, and deactivating sending of an RLC ARQ to terminate ongoing retransmissions.

[0010] In some examples: prior to the receiving one or more data units of the data unit set using the first set of RLC parameters, the UE is further caused to: configure, based on a received first activation indication to activate the first retransmission policy, the plurality of RLC parameters to the first set of RLC parameters.

[0011] In some examples, the first activation indication is carried via an RLC control Protocol Data Unit (PDU), or other Layer-2 signaling messages.

[0012] In some examples: in response to the determination that the received one or more data units of the data unit set meets the predetermined threshold, the UE is further caused to: receive, from the network node, a second activation indication to activate the second retransmission policy; and configure, based on the received second activation indication, the plurality of RLC parameters to the second set of RLC parameters.

[0013] In some examples, the second activation indication is carried via an RLC control Protocol Data Unit (PDU), or other Layer-2 signaling messages, and / or the second activation indication is used to inform the UE of discontinuation of expected RLC retransmissions. Optionally, the UE is further caused to update a reception RLC window to adapt to the discontinuation of expected RLC retransmissions.

[0014] In some examples, the UE is further caused to: receive information related to an error correction configuration indicative of the one or more error correction characteristics from an application layer; and switch, based on the received information related to the error correction configuration and a current status of data unit reception, among at least the first retransmission policy and the second retransmission policy for receiving further data units of the data unit set.

[0015] In some examples, the UE is further caused to communicate to the network node a capability to support error correction (EC) -aware RLC policy switching based on the received information related to the error correction configuration.

[0016] In some examples: the capability to support EC-aware RLC policy switching comprises one of the following: the capability to support UE-autonomous EC-aware RLC policy switching based on at least a determination policy that the received one or more data units of the data unit set meets the predetermined threshold, or the capability to support network-controlled EC-aware RLC policy switching based on an indication signaled by the network node.

[0017] In some examples, the one or more error correction characteristics comprises forward error correction (FEC) information indicative of decodability of the data unit set specified by an application layer.

[0018] In accordance with a second aspect of the present disclosure, there is provided a network node of a radio access network, configured to support an Automatic Repeat Request (ARQ) process when communicating with a User Equipment (UE), the network node comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the network node least to: configure the UE with a configuration message for controlling a radio link between the network node and the UE, the configuration message comprising a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate; transmit, to the UE, one or more data units of a data unit set using the first set of RLC parameters; determine, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the transmitted one or more data units of the data unit set meets the predetermined threshold; and, in response to the determination,transmit, to the UE, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0019] In some examples, the first set of RLC parameters defines a first retransmission policy enabling the first retransmission rate and the second set of RLC parameters defines a second retransmission policy enabling the second retransmission rate. Moreover, the network node is further caused to select the second retransmission policy for transmitting the one or more remaining data units of the data unit set in response to the determination.

[0020] In some examples, the predetermined threshold to be met comprises a required amount of data to be delivered to the UE for successfully decoding the data unit set, and the determination comprises determining that a delivered amount of data which has been delivered to the UE fulfills the required amount of data. Optionally, the delivered amount of data which has been delivered to the UE comprises at least one of the following: a certain number or percentage of data units within the data unit set, a certain number of bytes within the data unit set, or a certain percentage value of total size of the data unit set.

[0021] In some examples, the plurality of RLC parameters comprises at least one of the following: a maximum number of retransmissions, a preconfigured time for triggering a retransmission, a T-reassembly timer, a T-PollRetransmit timer, a T-StatusProhibit timer, or a probability for triggering a blind retransmission.

[0022] In some examples: for defining the second retransmission policy, the second set of RLC parameters is set based on one or more of the following: increasing a duration of one or more of the T-reassembly timer, the T-PollRetransmit timer, and the T-StatusProhibit timer, reducing the maximum number of retransmissions, disabling the preconfigured time for triggering a retransmission and / or the probability for triggering a blind retransmission, and deactivating sending of an RLC ARQ to terminate ongoing retransmissions.

[0023] In some examples: prior to the transmitting one or more data units of the data unit set using the first set of RLC parameters, the network node is further caused to: select the first set of RLC parameters specified for the first retransmission policy for transmitting the one or more data units of the data unit set; and send, to the UE, a first activation indication to activate the first retransmission policy.

[0024] In some examples, the first activation indication is carried via an RLC control Protocol Data Unit (PDU), or other Layer-2 signaling messages.

[0025] In some examples: in response to the determination that the transmitted one or more data units of the data unit set meets the predetermined threshold, the network node is further caused to send, to the UE, a second activation indication to activate the second retransmission policy.

[0026] In some examples, the second activation indication is carried via an RLC control Protocol Data Unit (PDU), or other Layer-2 signaling messages, and / or the second activation indication is used to inform the UE of discontinuation of expected RLC retransmissions.

[0027] In some examples, the network node is further caused to: receive information related to an error correction configuration indicative of the one or more error correction characteristics from an application layer; and switch, based on the received information related to the error correction configuration and a current status of data unit reception, among at least the first retransmission policy and the second retransmission policy for transmitting further data units of the data unit set.

[0028] In some examples, the network node is further caused to receive information from the UE of a capability to support error correction (EC) -aware RLC policy switching based on the received information related to error correction configuration.

[0029] In some examples, the capability to support EC-aware RLC policy switching comprises one of the following: the capability to support UE-autonomous EC-aware RLC policy switching based on at least a determination policy that the transmitted one or more data units of the data unit set meets the predetermined threshold, or the capability to support network-controlled EC-aware RLC policy switching based on an indication signaled by the network node.

[0030] In some examples, the one or more error correction characteristics comprises forward error correction (FEC) information indicative of decodability of the data unit set specified by an application layer.

[0031] In accordance with a third aspect of the present disclosure, there is provided a system, comprising: a user equipment (UE) according to any one of the first aspect and its related examples, and a network node according to any one of the second aspect and its related examples, whereinthe UE and the network node are configured to support an Automatic Repeat Request (ARQ) process when communicating with each other.

[0032] In accordance with a fourth aspect of the present disclosure, there is provided a method of a User Equipment (UE) that supports an Automatic Repeat Request (ARQ) process when communicating with a network node of a radio access network in accordance with configuration information including a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate, the method comprising: receiving, from the network node, one or more data units of a data unit set using the first set of RLC parameters; and in response to a determination, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the received one or more data units of the data unit set meets the predetermined threshold, receiving, from the network node, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0033] In accordance with a fifth aspect of the present disclosure, there is provided a method of a network node that supports an Automatic Repeat Request (ARQ) process when communicating with a User Equipment (UE), the method comprising: configuring the UE with a configuration message for controlling a radio link between the network node and the UE, the configuration message comprising a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate; transmitting, to the UE, one or more data units of a data unit set using the first set of RLC parameters; determining, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the transmitted one or more data units of the data unit set meets the predetermined threshold; andin response to the determination, transmitting, to the UE, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0034] In accordance with a sixth aspect of the present disclosure, there is provided a User Equipment (UE) configured to support an Automatic Repeat Request (ARQ) process when communicating with a network node of a radio access network in accordance with configuration information. In particular, the configuration information includes a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate, the UE comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the UE at least to: transmit, to the network node, one or more data units of a data unit set using the first set of RLC parameters; determine, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the transmitted one or more data units of the data unit set meets the predetermined threshold; and in response to the determination, transmit, to the network node, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0035] In some examples, the first set of RLC parameters defines a first retransmission policy enabling the first retransmission rate and the second set of RLC parameters defines a second retransmission policy enabling the second retransmission rate. Moreover, the UE is further caused to change to the second retransmission policy for transmitting the one or more remaining data units of the data unit set in response to the determination.

[0036] In some examples, the predetermined threshold to be met comprises a required amount of data to be delivered to the network node for successfully decoding the data unit set, and the determination comprises determining that a delivered amount of data which has been delivered to the network node fulfills the required amount of data, and optionally, wherein the delivered amount of data which has been delivered to the network node comprises at least oneof the following: a certain number or percentage of data units within the data unit set, a certain number of bytes within the data unit set, or a certain percentage value of total size of the data unit set.

[0037] In some examples, the UE is further caused to receive, from the network node, a configuration message including the configuration information for controlling a radio link between the UE and the network node. Optionally, the plurality of RLC parameters comprises at least one of the following: a maximum number of retransmissions, a preconfigured time for triggering a retransmission, a T-reassembly timer, a T-PollRetransmit timer, a T-StatusProhibit timer, or a probability for triggering a blind retransmission.

[0038] In some examples: for defining the second retransmission policy, the second set of RLC parameters is set based on one or more of the following: increasing a duration of one or more of the T-reassembly timer, the T-PollRetransmit timer, and the T-StatusProhibit timer, reducing the maximum number of retransmissions, disabling the preconfigured time for triggering a retransmission and / or the probability for triggering a blind retransmission, and deactivating sending of an RLC ARQ to terminate ongoing retransmissions.

[0039] In some examples, prior to the transmitting one or more data units of the data unit set using the first set of RLC parameters, the UE is further caused to send, to the network node, a first activation indication to inform the network node of error correction (EC) -based handling for the RLC ARQ process carrying data from the data unit set and to activate the first retransmission policy.

[0040] In some examples, in response to the determination that the transmitted one or more data units of the data unit set meets the predetermined threshold, the UE is further caused to send, to the network node, a second activation indication to activate the second retransmission policy. Optionally, the second activation indication is carried via an RLC control Protocol Data Unit (PDU).

[0041] In some examples, the second activation indication is used to inform the network node of discontinuation of expected RLC retransmissions. Alternatively or in addition, the second activation indication is carried via an RLC control Protocol Data Unit (PDU).

[0042] In some examples, the UE is further caused to:receive information related to an error correction configuration indicative of the one or more error correction characteristics from an application layer; and switch, based on the received information related to the error correction configuration and a current status of data unit reception, among at least the first retransmission policy and the second retransmission policy for transmitting further data units of the data unit set.

[0043] In some examples, the UE is further caused to communicate to the network node a capability to support error correction (EC) -aware RLC policy switching based on the received information related to an error correction configuration.

[0044] In some examples: the capability to support EC-aware RLC policy switching comprises one of the following: the capability to support UE-autonomous EC-aware RLC policy switching based on at least a determination policy that the received one or more data units of the data unit set meets the predetermined threshold, or the capability to support network-controlled EC-aware RLC policy switching based on an indication signaled by the network node.

[0045] In some examples, the UE is further caused to receive, from the network node, a further configuration message relating to mapping of the data unit set for a Quality-of-Service (QoS) flow to a Logical Channel (LCH).

[0046] In some examples, the UE is further caused to: receive, from a core network entity, the one or more error correction characteristics for data unit sets in a QoS flow or a data unit session; and, optionally, inform the network node about the one or more error correction characteristics using Radio Resource Control (RRC) UE assistance information (UAI) framework.

[0047] In some examples, the UE is further caused to send the one or more error correction characteristics to the network node for determining whether a sufficient amount of data has been successfully delivered for decoding the data unit set.

[0048] In some examples, the one or more error correction characteristics comprises forward error correction (FEC) information indicative of decodability of the data unit set specified by an application layer.

[0049] In accordance with a seventh aspect of the present disclosure, there is provided a network node of a radio access network, configured to support an Automatic Repeat Request (ARQ) process when communicating with a User Equipment (UE), the network node comprising:at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the network node least to: configure the UE with a configuration message for controlling a radio link between the network node and the UE, the configuration message comprising a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate; receive, from the UE, one or more data units of a data unit set using the first set of RLC parameters; and in response to a determination, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the received one or more data units of the data unit set meets the predetermined threshold, receive, from the UE, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0050] In some examples, the first set of RLC parameters defines a first retransmission policy enabling the first retransmission rate and the second set of RLC parameters defines a second retransmission policy enabling the second retransmission rate. Moreover, the network node is further caused to select the second retransmission policy for receiving the one or more remaining data units of the data unit set in response to the determination.

[0051] In some examples, the predetermined threshold to be met comprises a required amount of data to be received by the network node for successfully decoding the data unit set, and the determination comprises determining that a received amount of data which has been received by the network node fulfills the required amount of data. Optionally, the received amount of data which has been received by the network node comprises at least one of the following: a certain number or percentage of data units within the data unit set, a certain number of bytes within the data unit set, or a certain percentage value of total size of the data unit set.

[0052] In some examples, the plurality of RLC parameters comprises at least one of the following: a maximum number of retransmissions, a preconfigured time for triggering a retransmission, a T-reassembly timer, a T-PollRetransmit timer, a T-StatusProhibit timer, or a probability for triggering a blind retransmission.

[0053] In some examples:for defining the second retransmission policy, the second set of RLC parameters is set based on one or more of the following: increasing a duration of one or more of the T-reassembly timer, the T-PollRetransmit timer, and the T-StatusProhibit timer, reducing the maximum number of retransmissions, disabling the preconfigured time for triggering a retransmission and / or the probability for triggering a blind retransmission, and deactivating sending of an RLC ARQ to terminate ongoing retransmissions.

[0054] In some examples: prior to the receiving one or more data units of the data unit set using the first set of RLC parameters, the network node is further caused to: receive, from the UE, a first activation indication indicative of error correction (EC) -based handling for the RLC ARQ process carrying data from the data unit set to activate the first retransmission policy; and configure, based on the received first activation indication, the plurality of RLC parameters to the first set of RLC parameters.

[0055] In some examples: in response to the determination that the received one or more data units of the data unit set meets the predetermined threshold, the network node is further caused to: receive, from the UE, a second activation indication to activate the second retransmission policy; and configure, based on the received second activation indication, the plurality of RLC parameters to the second set of RLC parameters.

[0056] In some examples, the second activation indication is used to inform the network node of discontinuation of expected RLC retransmissions, and optionally, the second activation indication is carried via an RLC control Protocol Data Unit (PDU).

[0057] In some examples, the network node is further caused to update a reception RLC window to adapt to the discontinuation of expected RLC retransmissions.

[0058] In some examples, the network node is further caused to: receive, from a core network entity, information related to an error correction configuration indicative of the one or more error correction characteristics for data unit sets in a QoS flow or a data unit session, orreceive, from the UE, the information related to the error correction configuration using Radio Resource Control (RRC) UE assistance information (UAI) framework.

[0059] In some examples, the network node is further caused to receive, from the UE, the one or more error correction characteristics and to track delivery of data units of the data unit set, and the network node is further caused to determine, based on the received one or more error correction characteristics and delivered data units of the data unit set, whether a sufficient amount of data has been successfully delivered for decoding the data unit set.

[0060] In some examples, the network node is further caused to map the data unit set for a Quality-of-Service (QoS) flow to a Logical Channel (LCH).

[0061] In some examples, the network node is further caused to: receive information related to an error correction configuration indicative of the one or more error correction characteristics from an application layer; and switch, based on the received information related to the error correction configuration and a current status of data unit reception, among at least the first retransmission policy and the second retransmission policy for receiving further data units of the data unit set.

[0062] In some examples, the network node is further caused to receive information from the UE of a capability to support error correction (EC) -aware RLC policy switching based on the received information related to the error correction configuration.

[0063] In some examples, the capability to support EC-aware RLC policy switching comprises one of the following: the capability to support UE-autonomous EC-aware RLC policy switching based on at least a determination policy that the transmitted one or more data units of the data unit set meets the predetermined threshold, or the capability to support network-controlled EC-aware RLC policy switching based on an indication signaled by the network node.

[0064] In some examples, the one or more error correction characteristics comprises forward error correction (FEC) information indicative of decodability of the data unit set specified by an application layer.

[0065] In accordance with an eighth aspect of the present disclosure, there is provided a system, comprising: a user equipment (UE) according to any one of the sixth aspect and its related examples, and a network node according to any one of the seventh aspect and its related examples, whereinthe UE and the network node are configured to support an Automatic Repeat Request (ARQ) process when communicating with each other.

[0066] In accordance with a nineth aspect of the present disclosure, there is provided a method of a User Equipment (UE) that supports an Automatic Repeat Request (ARQ) process when communicating with a network node of a radio access network in accordance with configuration information including a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate, the method comprising: transmitting, to the network node, one or more data units of a data unit set using the first set of RLC parameters; determining, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the transmitted one or more data units of the data unit set meets the predetermined threshold; and, in response to the determination, transmitting, to the network node, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0067] In accordance with a tenth aspect of the present disclosure, there is provided a method of a network node that supports an Automatic Repeat Request (ARQ) process when communicating with a User Equipment (UE), the method comprising: configuring the UE with a configuration message for controlling a radio link between the network node and the UE, the configuration message comprising a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate; receiving, from the UE, one or more data units of a data unit set using the first set of RLC parameters; and in response to a determination, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the received one or more data units of the data unit set meets the predeterminedthreshold, receiving, from the UE, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0068] In accordance with an eleventh aspect of the present disclosure, there is provided a User Equipment (UE) configured to support an Automatic Repeat Request (ARQ) process when communicating with a network node of a radio access network in accordance with configuration information. In particular, the configuration information includes a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate higher than the first retransmission rate, the UE comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the UE at least to: receive, from the network node, one or more data units of a data unit set using the first set of RLC parameters; and in response to a determination, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the received one or more data units of the data unit set does not meet the predetermined threshold, receive, from the network node, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0069] In some examples, the first set of RLC parameters defines a first retransmission policy enabling the first retransmission rate and the second set of RLC parameters defines a second retransmission policy enabling the second retransmission rate. Moreover, the UE is further caused to select the second retransmission policy for receiving the one or more remaining data units of the data unit set in response to the determination.

[0070] In some examples, the predetermined threshold to be met comprises a required amount of data to be received by the UE for successfully decoding the data unit set, and the determination comprises determining that a received amount of data which has been received by the UE within a predetermined time window does not fulfill the required amount of data. Optionally, the received amount of data which has been received by the UE comprises at least one of the following: a certain number or percentage of data units within the data unit set, a certain number of bytes within the data unit set, or a certain percentage value of total size of the data unit set.

[0071] In some examples, the UE is further caused to receive, from the network node, a configuration message including the configuration information for controlling a radio link between the UE and the network node. Optionally, the plurality of RLC parameters comprises at least one of the following: a maximum number of retransmissions, a preconfigured time for triggering a retransmission, a T-reassembly timer, a T-PollRetransmit timer, a T-StatusProhibit timer, or a probability for triggering a blind retransmission.

[0072] In some examples: for defining the second retransmission policy, the second set of RLC parameters is set based on one or more of the following: decreasing a duration of one or more of the T-reassembly timer, the T-PollRetransmit timer, and the T-StatusProhibit timer, increasing the maximum number of retransmissions, enabling the preconfigured time for triggering a retransmission regardless of a status of data unit delivery, and setting the probability for triggering a blind retransmission to 1.

[0073] In some examples: prior to the receiving one or more data units of the data unit set using the first set of RLC parameters, the UE is further caused to: configure, based on a received first activation indication to activate the first retransmission policy, the plurality of RLC parameters to the first set of RLC parameters.

[0074] In some examples, the first activation indication is carried via an RLC control Protocol Data Unit (PDU), or other Layer-2 signaling messages.

[0075] In some examples: in response to the determination that the received one or more data units of the data unit set does not meet the predetermined threshold, the UE is further caused to: receive, from the network node, a second activation indication to activate the second retransmission policy; and configure, based on the received second activation indication, the plurality of RLC parameters to the second set of RLC parameters.

[0076] In some examples, the second activation indication is carried via an RLC control Protocol Data Unit (PDU), or other Layer-2 signaling messages, and / or the second activation indication is used to inform the UE of an increased rate of further RLC retransmissions, and,optionally, the UE is further caused to update a reception RLC window to adapt to the increased rate of further RLC retransmissions.

[0077] In some examples, the UE is further caused to: receive information related to an error correction configuration indicative of the one or more error correction characteristics from an application layer; and switch, based on the received information related to the error correction configuration and a current status of data unit reception, among at least the first retransmission policy and the second retransmission policy for receiving further data units of the data unit set.

[0078] In some examples, the UE is further caused to communicate to the network node a capability to support error correction (EC) -aware RLC policy switching based on the received information related to the error correction configuration.

[0079] In some examples: the capability to support EC-aware RLC policy switching comprises one of the following: the capability to support UE-autonomous EC-aware RLC policy switching based on at least a determination policy that the received one or more data units of the data unit set does not meet the predetermined threshold, or the capability to support network-controlled EC-aware RLC policy switching based on an indication signaled by the network node.

[0080] In some examples, the one or more error correction characteristics comprises forward error correction (FEC) information indicative of decodability of the data unit set specified by an application layer.

[0081] In accordance with a twelfth aspect of the present disclosure, there is provided a network node of a radio access network, configured to support an Automatic Repeat Request (ARQ) process when communicating with a User Equipment (UE), the network node comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the network node least to: configure the UE with a configuration message for controlling a radio link between the network node and the UE, the configuration message comprising a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated witha first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate higher than the first retransmission rate; transmit, to the UE, one or more data units of a data unit set using the first set of RLC parameters; determine, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the transmitted one or more data units of the data unit set does not meet the predetermined threshold; and, in response to the determination, transmit, to the UE, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0082] In some examples, the first set of RLC parameters defines a first retransmission policy enabling the first retransmission rate and the second set of RLC parameters defines a second retransmission policy enabling the second retransmission rate. Moreover, the network node is further caused to select the second retransmission policy for transmitting the one or more remaining data units of the data unit set in response to the determination.

[0083] In some examples, the predetermined threshold to be met comprises a required amount of data to be delivered to the UE for successfully decoding the data unit set, and the determination comprises determining that a delivered amount of data which has been delivered to the UE within a predetermined time window does not fulfill the required amount of data. Optionally, the delivered amount of data which has been delivered to the UE comprises at least one of the following: a certain number or percentage of data units within the data unit set, a certain number of bytes within the data unit set, or a certain percentage value of total size of the data unit set.

[0084] In some examples, the plurality of RLC parameters comprises at least one of the following: a maximum number of retransmissions, a preconfigured time for triggering a retransmission, a T-reassembly timer, a T-PollRetransmit timer, a T-StatusProhibit timer, or a probability for triggering a blind retransmission.

[0085] In some examples: for defining the second retransmission policy, the second set of RLC parameters is set based on one or more of the following: decreasing a duration of one or more of the T-reassembly timer, the T-PollRetransmit timer, and the T-StatusProhibit timer, increasing the maximum number of retransmissions,enabling the preconfigured time for triggering a retransmission regardless of a status of data unit delivery, and setting the probability for triggering a blind retransmission to 1.

[0086] In some examples: prior to the transmitting one or more data units of the data unit set using the first set of RLC parameters, the network node is further caused to: select the first set of RLC parameters specified for the first retransmission policy for transmitting the one or more data units of the data unit set; and send, to the UE, a first activation indication to activate the first retransmission policy.

[0087] In some examples, the first activation indication is carried via an RLC control Protocol Data Unit (PDU), or other Layer-2 signaling messages.

[0088] In some examples: in response to the determination that the transmitted one or more data units of the data unit set does not meet the predetermined threshold, the network node is further caused to send, to the UE, a second activation indication to activate the second retransmission policy.

[0089] In some examples, the second activation indication is carried via an RLC control Protocol Data Unit (PDU), or other Layer-2 signaling messages, and / or the second activation indication is used to inform the UE of an increased rate of further RLC retransmissions.

[0090] In some examples, the network node is further caused to: receive information related to an error correction configuration indicative of the one or more error correction characteristics from an application layer; and switch, based on the received information related to the error correction configuration and a current status of data unit reception, among at least the first retransmission policy and the second retransmission policy for transmitting further data units of the data unit set.

[0091] In some examples, the network node is further caused to receive information from the UE of a capability to support error correction (EC) -aware RLC policy switching based on the received information related to error correction configuration.

[0092] In some examples, the capability to support EC-aware RLC policy switching comprises one of the following: the capability to support UE-autonomous EC-aware RLC policy switching based on at least a determination policy that the transmitted one or more data units of the data unit set does not meet the predetermined threshold, orthe capability to support network-controlled EC-aware RLC policy switching based on an indication signaled by the network node.

[0093] In some examples, the one or more error correction characteristics comprises forward error correction (FEC) information indicative of decodability of the data unit set specified by an application layer.

[0094] In accordance with a thirteen aspect of the present disclosure, there is provided a User Equipment (UE) configured to support an Automatic Repeat Request (ARQ) process when communicating with a network node of a radio access network in accordance with configuration information. In particular, the configuration information includes a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate higher than the first retransmission rate, the UE comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the UE at least to: transmit, to the network node, one or more data units of a data unit set using the first set of RLC parameters; determine, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the transmitted one or more data units of the data unit set does not meet the predetermined threshold; and in response to the determination, transmit, to the network node, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0095] In some examples, the first set of RLC parameters defines a first retransmission policy enabling the first retransmission rate and the second set of RLC parameters defines a second retransmission policy enabling the second retransmission rate. Moreover, the UE is further caused to change to the second retransmission policy for transmitting the one or more remaining data units of the data unit set in response to the determination.

[0096] In some examples, the predetermined threshold to be met comprises a required amount of data to be delivered to the network node for successfully decoding the data unit set, and the determination comprises determining that a delivered amount of data which has beendelivered to the network node within a predetermined time window does not fulfill the required amount of data, and optionally, wherein the delivered amount of data which has been delivered to the network node comprises at least one of the following: a certain number or percentage of data units within the data unit set, a certain number of bytes within the data unit set, or a certain percentage value of total size of the data unit set.

[0097] In some examples, the UE is further caused to receive, from the network node, a configuration message including the configuration information for controlling a radio link between the UE and the network node. Optionally, the plurality of RLC parameters comprises at least one of the following: a maximum number of retransmissions, a preconfigured time for triggering a retransmission, a T-reassembly timer, a T-PollRetransmit timer, a T-StatusProhibit timer, or a probability for triggering a blind retransmission.

[0098] In some examples: for defining the second retransmission policy, the second set of RLC parameters is set based on one or more of the following: decreasing a duration of one or more of the T-reassembly timer, the T-PollRetransmit timer, and the T-StatusProhibit timer, increasing the maximum number of retransmissions, enabling the preconfigured time for triggering a retransmission regardless of a status of data unit delivery, and setting the probability for triggering a blind retransmission to 1.

[0099] In some examples, prior to the transmitting one or more data units of the data unit set using the first set of RLC parameters, the UE is further caused to send, to the network node, a first activation indication to inform the network node of error correction (EC) -based handling for the RLC ARQ process carrying data from the data unit set and to activate the first retransmission policy.

[0100] In some examples, in response to the determination that the transmitted one or more data units of the data unit set does not meet the predetermined threshold, the UE is further caused to send, to the network node, a second activation indication to activate the second retransmission policy. Optionally, the second activation indication is carried via an RLC control Protocol Data Unit (PDU).

[0101] In some examples, the second activation indication is used to inform the network node of an increased rate of further RLC retransmissions.

[0102] In some examples, the UE is further caused to:receive information related to an error correction configuration indicative of the one or more error correction characteristics from an application layer; and switch, based on the received information related to the error correction configuration and a current status of data unit reception, among at least the first retransmission policy and the second retransmission policy for transmitting further data units of the data unit set.

[0103] In some examples, the UE is further caused to communicate to the network node a capability to support error correction (EC) -aware RLC policy switching based on the received information related to an error correction configuration.

[0104] In some examples: the capability to support EC-aware RLC policy switching comprises one of the following: the capability to support UE-autonomous EC-aware RLC policy switching based on at least a determination policy that the transmitted one or more data units of the data unit set does not meet the predetermined threshold, or the capability to support network-controlled EC-aware RLC policy switching based on an indication signaled by the network node.

[0105] In some examples, the UE is further caused to receive, from the network node, a further configuration message relating to mapping of the data unit set for a Quality-of-Service (QoS) flow to a Logical Channel (LCH).

[0106] In some examples, the UE is further caused to: receive, from a core network entity, the one or more error correction characteristics for data unit sets in a QoS flow or a data unit session; and, optionally, inform the network node about the one or more error correction characteristics using Radio Resource Control (RRC) UE assistance information (UAI) framework.

[0107] In some examples, the UE is further caused to send the one or more error correction characteristics to the network node for determining whether a sufficient amount of data has been successfully delivered for decoding the data unit set.

[0108] In some examples, the one or more error correction characteristics comprises forward error correction (FEC) information indicative of decodability of the data unit set specified by an application layer.

[0109] In accordance with a fourteenth aspect of the present disclosure, there is provided a network node of a radio access network, configured to support an Automatic Repeat Request (ARQ) process when communicating with a User Equipment (UE), the network node comprising:at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the network node least to: configure the UE with a configuration message for controlling a radio link between the network node and the UE, the configuration message comprising a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate higher than the first retransmission rate; receive, from the UE, one or more data units of a data unit set using the first set of RLC parameters; and in response to a determination, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the received one or more data units of the data unit set does not meet the predetermined threshold, receive, from the UE, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0110] In some examples, the first set of RLC parameters defines a first retransmission policy enabling the first retransmission rate and the second set of RLC parameters defines a second retransmission policy enabling the second retransmission rate. Moreover, the network node is further caused to select the second retransmission policy for receiving the one or more remaining data units of the data unit set in response to the determination.

[0111] In some examples, the predetermined threshold to be met comprises a required amount of data to be received by the network node for successfully decoding the data unit set, and the determination comprises determining that a received amount of data which has been received by the network node within a predetermined time window does not fulfill the required amount of data. Optionally, the received amount of data which has been received by the network node comprises at least one of the following: a certain number or percentage of data units within the data unit set, a certain number of bytes within the data unit set, or a certain percentage value of total size of the data unit set.

[0112] In some examples, the plurality of RLC parameters comprises at least one of the following: a maximum number of retransmissions, a preconfigured time for triggering a retransmission, a T-reassembly timer, a T-PollRetransmit timer, a T-StatusProhibit timer, or a probability for triggering a blind retransmission.

[0113] In some examples: for defining the second retransmission policy, the second set of RLC parameters is set based on one or more of the following: decreasing a duration of one or more of the T-reassembly timer, the T-PollRetransmit timer, and the T-StatusProhibit timer, increasing the maximum number of retransmissions, enabling the preconfigured time for triggering a retransmission regardless of a status of data unit delivery, and setting the probability for triggering a blind retransmission to 1.

[0114] In some examples: prior to the receiving one or more data units of the data unit set using the first set of RLC parameters, the network node is further caused to: receive, from the UE, a first activation indication indicative of error correction (EC) -based handling for the RLC ARQ process carrying data from the data unit set to activate the first retransmission policy; and configure, based on the received first activation indication, the plurality of RLC parameters to the first set of RLC parameters.

[0115] In some examples: in response to the determination that the received one or more data units of the data unit set does not meet the predetermined threshold, the network node is further caused to: receive, from the UE, a second activation indication to activate the second retransmission policy; and configure, based on the received second activation indication, the plurality of RLC parameters to the second set of RLC parameters.

[0116] In some examples, the second activation indication is used to inform the network node of an increased rate of further RLC retransmissions, and optionally, the second activation indication is carried via an RLC control Protocol Data Unit (PDU).

[0117] In some examples, the network node is further caused to update a reception RLC window to adapt to the increased rate of further RLC retransmissions.

[0118] In some examples, the network node is further caused to: receive, from a core network entity, information related to an error correction configuration indicative of the one or more error correction characteristics for data unit sets in a QoS flow or a data unit session, orreceive, from the UE, the information related to the error correction configuration using Radio Resource Control (RRC) UE assistance information (UAI) framework.

[0119] In some examples, the network node is further caused to receive, from the UE, the one or more error correction characteristics and to track delivery of data units of the data unit set, and the network node is further caused to determine, based on the received one or more error correction characteristics and delivered data units of the data unit set, whether a sufficient amount of data has been successfully delivered for decoding the data unit set.

[0120] In some examples, the network node is further caused to map the data unit set for a Quality-of-Service (QoS) flow to a Logical Channel (LCH).

[0121] In some examples, the network node is further caused to: receive information related to an error correction configuration indicative of the one or more error correction characteristics from an application layer; and switch, based on the received information related to the error correction configuration and a current status of data unit reception, among at least the first retransmission policy and the second retransmission policy for receiving further data units of the data unit set.

[0122] In some examples, the network node is further caused to receive information from the UE of a capability to support error correction (EC) -aware RLC policy switching based on the received information related to the error correction configuration.

[0123] In some examples, the capability to support EC-aware RLC policy switching comprises one of the following: the capability to support UE-autonomous EC-aware RLC policy switching based on at least a determination policy that the received one or more data units of the data unit set does not meet the predetermined threshold, or the capability to support network-controlled EC-aware RLC policy switching based on an indication signaled by the network node.

[0124] In some examples, the one or more error correction characteristics comprises forward error correction (FEC) information indicative of decodability of the data unit set specified by an application layer.

[0125] In accordance with a fifteenth aspect of the present disclosure, there is provided a system, comprising: a user equipment (UE) according to any one of the eleventh aspect and its related examples, and a network node according to any one of the twelfth aspect and its related examples, ora user equipment (UE) according to any one of the thirteenth aspect and its related examples, and a network node according to any one of the fourteenth aspect and its related examples, wherein the UE and the network node are configured to support an Automatic Repeat Request (ARQ) process when communicating with each other.

[0126] In accordance with a sixteenth aspect of the present disclosure, there is provided a method of a User Equipment (UE) that supports an Automatic Repeat Request (ARQ) process when communicating with a network node of a radio access network in accordance with configuration information including a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate higher than the first retransmission rate, the method comprising: receiving, from the network node, one or more data units of a data unit set using the first set of RLC parameters; and in response to a determination, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the received one or more data units of the data unit set does not meet the predetermined threshold, receiving, from the network node, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0127] In accordance with a seventeenth aspect of the present disclosure, there is provided a method of a network node that supports an Automatic Repeat Request (ARQ) process when communicating with a User Equipment (UE), the method comprising: configuring the UE with a configuration message for controlling a radio link between the network node and the UE, the configuration message comprising a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate higher than the first retransmission rate; transmitting, to the UE, one or more data units of a data unit set using the first set of RLC parameters; determining, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that thetransmitted one or more data units of the data unit set does not meet the predetermined threshold; and in response to the determination, transmitting, to the UE, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0128] In accordance with a eighteenth aspect of the present disclosure, there is provided a method of a User Equipment (UE) that supports an Automatic Repeat Request (ARQ) process when communicating with a network node of a radio access network in accordance with configuration information including a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate higher than the first retransmission rate, the method comprising: transmitting, to the network node, one or more data units of a data unit set using the first set of RLC parameters; determining, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the transmitted one or more data units of the data unit set does not meet the predetermined threshold; and, in response to the determination, transmitting, to the network node, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0129] In accordance with a nineteenth aspect of the present disclosure, there is provided a method of a network node that supports an Automatic Repeat Request (ARQ) process when communicating with a User Equipment (UE), the method comprising: configuring the UE with a configuration message for controlling a radio link between the network node and the UE, the configuration message comprising a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate higher than the first retransmission rate; receiving, from the UE, one or more data units of a data unit set using the first set of RLC parameters; andin response to a determination, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the received one or more data units of the data unit set does not meet the predetermined threshold, receiving, from the UE, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0130] In accordance with a twentieth aspect of the present disclosure, there is provided a computer program comprising instructions for causing an apparatus to perform the method according to the fourth aspect, for causing an apparatus to perform the method according to the fifth aspect, for causing an apparatus to perform the method according to the nineth aspect, for causing an apparatus to perform the method according to the tenth aspect, or for causing an apparatus to perform any one of the methods according to the sixteenth to the nineteenth aspects.

[0131] In accordance with a twenty -first aspect of the present disclosure, there is provided a memory storing computer readable instructions for causing an apparatus to perform the method according to the fourth aspect, for causing an apparatus to perform the method according to the fifth aspect, for causing an apparatus to perform the method according to the nineth aspect, for causing an apparatus to perform the method according to the tenth aspect, or for causing an apparatus to perform any one of the methods according to the sixteenth to the nineteenth aspects.

[0132] In accordance with a further aspect of the present disclosure, there is provided a User Equipment (UE) configured to support an Automatic Repeat Request (ARQ) process when communicating with a network node of a radio access network in accordance with configuration information. In particular, the configuration information includes a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate, the UE comprising means for performing: receiving, from the network node, one or more data units of a data unit set using the first set of RLC parameters; and in response to a determination, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set,that the received one or more data units of the data unit set meets the predetermined threshold, receiving, from the network node, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0133] In accordance with a further aspect of the present disclosure, there is provided a network node of a radio access network, configured to support an Automatic Repeat Request (ARQ) process when communicating with a User Equipment (UE), the network node comprising means for performing: configuring the UE with a configuration message for controlling a radio link between the network node and the UE, the configuration message comprising a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate; transmitting, to the UE, one or more data units of a data unit set using the first set of RLC parameters; determining, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the transmitted one or more data units of the data unit set meets the predetermined threshold; and in response to the determination, transmitting, to the UE, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0134] In accordance with a further aspect of the present disclosure, there is provided a User Equipment (UE) configured to support an Automatic Repeat Request (ARQ) process when communicating with a network node of a radio access network in accordance with configuration information. In particular, the configuration information includes a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate, the UE comprising means for performing:transmitting, to the network node, one or more data units of a data unit set using the first set of RLC parameters; determining, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the transmitted one or more data units of the data unit set meets the predetermined threshold; and, in response to the determination, transmitting, to the network node, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0135] In accordance with a further aspect of the present disclosure, there is provided a network node of a radio access network, configured to support an Automatic Repeat Request (ARQ) process when communicating with a User Equipment (UE), the network node comprising means for performing: configuring the UE with a configuration message for controlling a radio link between the network node and the UE, the configuration message comprising a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate; receiving, from the UE, one or more data units of a data unit set using the first set of RLC parameters; and in response to a determination, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the received one or more data units of the data unit set meets the predetermined threshold, receiving, from the UE, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0136] In accordance with a further aspect of the present disclosure, there is provided a User Equipment (UE) configured to support an Automatic Repeat Request (ARQ) process when communicating with a network node of a radio access network in accordance with configuration information. In particular, the configuration information includes a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a secondretransmission rate higher than the first retransmission rate, the UE comprising means for performing: receiving, from the network node, one or more data units of a data unit set using the first set of RLC parameters; and in response to a determination, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the received one or more data units of the data unit set does not meet the predetermined threshold, receiving, from the network node, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0137] In accordance with a further aspect of the present disclosure, there is provided a network node of a radio access network, configured to support an Automatic Repeat Request (ARQ) process when communicating with a User Equipment (UE), the network node comprising means for performing: configuring the UE with a configuration message for controlling a radio link between the network node and the UE, the configuration message comprising a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate higher than the first retransmission rate; transmitting, to the UE, one or more data units of a data unit set using the first set of RLC parameters; determining, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the transmitted one or more data units of the data unit set does not meet the predetermined threshold; and in response to the determination, transmitting, to the UE, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0138] In accordance with a further aspect of the present disclosure, there is provided a User Equipment (UE) configured to support an Automatic Repeat Request (ARQ) process when communicating with a network node of a radio access network in accordance with configuration information. In particular, the configuration information includes a plurality of Radio LinkControl (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate higher than the first retransmission rate, the UE comprising means for performing: transmitting, to the network node, one or more data units of a data unit set using the first set of RLC parameters; determining, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the transmitted one or more data units of the data unit set does not meet the predetermined threshold; and, in response to the determination, transmitting, to the network node, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0139] In accordance with a further aspect of the present disclosure, there is provided a network node of a radio access network, configured to support an Automatic Repeat Request (ARQ) process when communicating with a User Equipment (UE), the network node comprising means for performing: configuring the UE with a configuration message for controlling a radio link between the network node and the UE, the configuration message comprising a plurality of Radio Link Control (RLC) parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate higher than the first retransmission rate; receiving, from the UE, one or more data units of a data unit set using the first set of RLC parameters; and in response to a determination, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the received one or more data units of the data unit set does not meet the predetermined threshold, receiving, from the UE, one or more remaining data units of the data unit set using the second set of RLC parameters.

[0140] In addition, according to some other example embodiments, there is provided, for example, a computer program product for a wireless communication device comprising at leastone processor, including software code portions for performing the respective steps disclosed in the present disclosure, when said product is run on the device. The computer program product may include a computer-readable medium on which said software code portions are stored. Furthermore, the computer program product may be directly loadable into the internal memory of the computer and / or transmittable via a network by means of at least one of upload, download and push procedures.

[0141] While some example embodiments will be described herein with particular reference to the above application, it will be appreciated that the present disclosure is not limited to such a field of use, and is applicable in broader contexts.

[0142] Notably, it is understood that methods according to the present disclosure relate to methods of operating the apparatuses according to the above example embodiments and variations thereof, and that respective statements made with regard to the apparatuses likewise apply to the corresponding methods, and vice versa, such that similar description may be omitted for the sake of conciseness. In addition, the above aspects may be combined in many ways, even if not explicitly disclosed. The skilled person will understand that these combinations of aspects and features / steps are possible unless it creates a contradiction which is explicitly excluded.

[0143] Implementations of the disclosed apparatuses may include using, but not limited to, one or more processor, one or more application specific integrated circuit (ASIC) and / or one or more field programmable gate array (FPGA). Implementations of the apparatus may also include using other conventional and / or customized hardware such as software programmable processors, such as graphics processing unit (GPU) processors.

[0144] Other and further example embodiments of the present disclosure will become apparent during the course of the following discussion and by reference to the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0145] Example embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

[0146] Figure 1 schematically illustrates an example of FEC based discard for XRM implementations;

[0147] Figure 2 schematically illustrates an example of a signaling diagram for a downlink RLC retransmission process according to an example embodiment of the present disclosure;

[0148] Figure 3 schematically illustrates an example of a signaling diagram for an uplink RLC retransmission process according to an example embodiment of the present disclosure;

[0149] Figure 4 illustrates an example of a method 400 of a UE for controlling RLC retransmissions in an ARQ process in accordance with embodiments of the disclosure;

[0150] Figure 5 illustrates an example of a method 500 of a network node of a radio access network for controlling RLC retransmissions in an ARQ process in accordance with embodiments of the disclosure;

[0151] Figure 6 illustrates an example of a method 600 of a UE for controlling RLC retransmissions in an ARQ process in accordance with embodiments of the disclosure; and

[0152] Figure 7 illustrates an example of a method 700 of a network node of a radio access network for controlling RLC retransmissions in an ARQ process in accordance with embodiments of the disclosure.DESCRIPTION OF EXAMPLE EMBODIMENTS

[0153] In the following, different exemplifying embodiments will be described using, as an example of a communication network to which examples of embodiments may be applied, a communication network architecture based on 3 GPP standards for a communication network, such as a 5G / NR, without restricting the embodiments to such an architecture, however. It is apparent for a person skilled in the art that the embodiments may also be applied to other kinds of communication networks where mobile communication principles are integrated with a D2D (device-to-device) or V2X (vehicle to everything) configuration, such as SL (side link), e.g. Wi-Fi, worldwide interoperability for microwave access (WiMAX), Bluetooth®, personal communications services (PCS), ZigBee®, wideband code division multiple access (WCDMA), systems using ultra-wideband (UWB) technology, mobile ad-hoc networks (MANETs), wired access, etc. Furthermore, without loss of generality, the description of some examples of embodiments is related to a mobile communication network, but principles of the disclosure can be extended and applied to any other type of communication network, such as a wired communication network.

[0154] The following examples and embodiments are to be understood only as illustrative examples. Although the specification may refer to “an”, “one”, or “some” example(s) or embodiment(s) in several locations, this does not necessarily mean that each such reference is related to the same example(s) or embodiment(s), or that the feature only applies to a single example or embodiment. Single features of different embodiments may also be combined toprovide other embodiments. Furthermore, terms like “comprising” and “including” should be understood as not limiting the described embodiments to consist of only those features that have been mentioned; such examples and embodiments may also contain features, structures, units, modules, etc., that have not been specifically mentioned.

[0155] A basic system architecture of a (tele)communication network including a mobile communication system where some examples of embodiments are applicable may include an architecture of one or more communication networks including wireless access network subsystem(s) and core network(s). Such an architecture may include one or more communication network control elements or functions, access network elements, radio access network elements, access service network gateways or base transceiver stations, such as a base station (BS), an access point (AP), a NodeB (NB), an eNB or a gNB, a distributed unit (DU) or a centralized / central unit (CU), which controls a respective coverage area or cell(s) and with which one or more communication stations such as communication elements or functions, like user devices or terminal devices, like a user equipment (UE), or another device having a similar function, such as a modem chipset, a chip, a module etc., which can also be part of a station, an element, a function or an application capable of conducting a communication, such as a UE, an element or function usable in a machine-to-machine communication architecture, or attached as a separate element to such an element, function or application on capable of conducting a communication, or the like, are capable to communicate via one or more channels via one or more communication beams for transmitting several types of data in a plurality of access domains. Furthermore, core network elements or network functions, such as gateway network elements / functions, mobility management entities, a mobile switching center, servers, databases and the like may be included.

[0156] The following description may provide further details of alternatives, modifications and variances: a gNB comprises e.g., a node providing NR user plane and control plane protocol terminations towards the UE, and connected via the NG interface to the 5GC, e.g., according to 3GPP TS 38.300 V16.6.0 (2021-06) section 3.2 incorporated by reference.

[0157] A gNB Central Unit (gNB-CU) comprises e.g., a logical node hosting e.g., RRC, SDAP and PDCP protocols of the gNB or RRC and PDCP protocols of the en-gNB that controls the operation of one or more gNB-DUs. The gNB-CU terminates the Fl interface connected with the gNB-DU.

[0158] A gNB Distributed Unit (gNB-DU) comprises e.g., a logical node hosting e.g., RLC, MAC and PHY layers of the gNB or en-gNB, and its operation is partly controlled by the gNB-CU. One gNB-DU supports one or multiple cells. One cell is supported by only one gNB-DU. The gNB-DU terminates the Fl interface connected with the gNB-CU.

[0159] A gNB-CU-Control Plane (gNB-CU-CP) comprises e.g., a logical node hosting e.g., the RRC and the control plane part of the PDCP protocol of the gNB-CU for an en-gNB or a gNB. The gNB-CU-CP terminates the El interface connected with the gNB-CU-UP and the Fl-C interface connected with the gNB-DU.

[0160] A gNB-CU-User Plane (gNB-CU-UP) comprises e.g., a logical node hosting e.g., the user plane part of the PDCP protocol of the gNB-CU for an en-gNB, and the user plane part of the PDCP protocol and the SDAP protocol of the gNB-CU for a gNB. The gNB-CU-UP terminates the El interface connected with the gNB-CU-CP and the Fl-U interface connected with the gNB-DU, e.g., according to 3GPP TS 38.401 V16.6.0 (2021-07) section 3.1 incorporated by reference.

[0161] Different functional splits between the central and distributed unit are possible, e.g., called options:Option 1 (lA-like split):• The function split in this option is similar to the 1 A architecture in DC. RRC is in the central unit. PDCP, RLC, MAC, physical layer and RF are in the distributed unit.Option 2 (3C-like split):• The function split in this option is similar to the 3C architecture in DC. RRC and PDCP are in the central unit. RLC, MAC, physical layer and RF are in the distributed unit.Option 3 (intra RLC split):• Low RLC (partial function of RLC), MAC, physical layer and RF are in the distributed unit. PDCP and high RLC (the other partial function of RLC) are in the central unit.Option 4 (RLC-MAC split):• MAC, physical layer and RF are in the distributed unit. PDCP and RLC are in the central unit.Or else, e.g., according to 3GPP TR 38.801 V14.0.0 (2017-03) section 11 incorporated by reference.

[0162] A gNB supports different protocol layers, e.g., Layer 1 (LI) - physical layer.

[0163] The layer 2 (L2) of NR is split into the following sublayers: Medium Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP) and Service Data Adaptation Protocol (SDAP), where e.g. :• The physical layer offers to the MAC sublayer transport channels;• The MAC sublayer offers to the RLC sublayer logical channels;• The RLC sublayer offers to the PDCP sublayer RLC channels;• The PDCP sublayer offers to the SDAP sublayer radio bearers;• The SDAP sublayer offers to 5GC QoS flows;• Comp, refers to header compression and Segm. To segmentation;• Control channels include (BCCH, PCCH).

[0164] Layer 3 (L3) includes e.g., Radio Resource Control (RRC), e.g., according to 3GPP TS 38.300 V16.6.0 (2021-06) section 6 incorporated by reference.

[0165] A RAN (Radio Access Network) node or network node like e.g. a gNB, base station, gNB CU or gNB DU or parts thereof may be implemented using e.g. an apparatus with at least one processor and / or at least one memory (with computer-readable instructions (computer program)) configured to support and / or provision and / or process CU and / or DU related functionality and / or features, and / or at least one protocol (sub-)layer of a RAN (Radio Access Network), e.g. layer 2 and / or layer 3.

[0166] The gNB CU and gNB DU parts may e.g., be co-located or physically separated. The gNB DU may even be split further, e.g., into two parts, e.g., one including processing equipment and one including an antenna. A Central Unit (CU) may also be called BBU / REC / RCC / C- RAN / V-RAN, 0-RAN, or part thereof. A Distributed Unit (DU) may also be called RRH / RRU / RE / RU, or part thereof. Hereinafter, in various example embodiments of the present disclosure, the CU-CP (or more generically, the CU) may also be referred to as a (first) network node that supports at least one of central unit control plane functionality or a layer 3 protocol of a radio access network; and similarly, the DU may be referred to as a (second) network node that supports at least one of distributed unit functionality or the layer 2 protocol of the radio access network.

[0167] A gNB-DU supports one or multiple cells, and could thus serve as e.g., a serving cell for a user equipment (UE).

[0168] A user equipment (UE) may include a wireless or mobile device, an apparatus with a radio interface to interact with a RAN (Radio Access Network), a smartphone, an in-vehicle apparatus, an loT device, a M2M (Machine-to-Machine) device, or else. Such UE or apparatusmay comprise: 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 apparatus at least to perform certain operations, like e.g. RRC connection to the RAN. A UE is e.g., configured to generate a message (e.g., including a cell ID) to be transmitted via radio towards a RAN (e.g., to reach and communicate with a serving cell). A UE may generate and transmit and receive RRC messages containing one or more RRC PDUs (Packet Data Units).

[0169] The UE may have different states (e.g., according to 3GPP TS 38.331 V16.5.0 (2021- 06) sections 42.1 and 4.4, incorporated by reference).

[0170] A UE is e.g., either in RRC CONNECTED state or in RRC INACTIVE state when an RRC connection has been established.

[0171] In RRC CONNECTED state a UE may :• store the AS context;• transfer unicast data to / from the UE;• monitor control channels associated with the shared data channel to determine if data is scheduled for the data channel;• provide channel quality and feedback information;• perform neighboring cell measurements and measurement reporting.

[0172] The RRC protocol includes e.g. the following main functions:• RRC connection control;• measurement configuration and reporting;• establishment / modification / release of measurement configuration (e.g. intrafrequency, inter-frequency and inter-RAT measurements);• setup and release of measurement gaps;• measurement reporting.

[0173] The general functions and interconnections of the described elements and functions, which also depend on the actual network type, are known to those skilled in the art and described in corresponding specifications, so that a detailed description thereof may omitted herein for the sake of conciseness. However, it is to be noted that several additional network elements and signaling links may be employed for a communication to or from an element, function or application, like a communication endpoint, a communication network control element, such as a server, a gateway, a radio network controller, and other elements of the same or other communication networks besides those described in detail herein below.

[0174] A communication network architecture as being considered in examples of embodiments may also be able to communicate with other networks, such as a public switched telephone network or the Internet. The communication network may also be able to support the usage of cloud services for virtual network elements or functions thereof, wherein it is to be noted that the virtual network part of the telecommunication network can also be provided by non-cloud resources, e.g. an internal network or the like. It should be appreciated that network elements of an access system, of a core network etc., and / or respective functionalities may be implemented by using any node, host, server, access node or entity etc. being suitable for such a usage. Generally, a network function can be implemented either as a network element on a dedicated hardware, as a software instance running on a dedicated hardware, or as a virtualized function instantiated on an appropriate platform, e.g., a cloud infrastructure.

[0175] Furthermore, a network element, such as communication elements, like a UE, a terminal device, control elements or functions, such as access network elements, like a base station / BS, a gNB, a radio network controller, a core network control element or function, such as a gateway element, or other network elements or functions, as described herein, and any other elements, functions or applications may be implemented by software, e.g., by a computer program product for a computer, and / or by hardware. For executing their respective processing, correspondingly used devices, nodes, functions or network elements may include several means, modules, units, components, etc. (not shown) which are required for control, processing and / or communication / signaling functionality. Such means, modules, units and components may include, for example, one or more processors or processor units including one or more processing portions for executing instructions and / or programs and / or for processing data, storage or memory units or means for storing instructions, programs and / or data, for serving as a work area of the processor or processing portion and the like (e.g. ROM, RAM, EEPROM, and the like), input or interface means for inputting data and instructions by software (e.g. floppy disc, CD-ROM, EEPROM, and the like), a user interface for providing monitor and manipulation possibilities to a user (e.g. a screen, a keyboard and the like), other interface or means for establishing links and / or connections under the control of the processor unit or portion (e.g. wired and wireless interface means, radio interface means including e.g. an antenna unit or the like, means for forming a radio communication part etc.) and the like, wherein respective means forming an interface, such as a radio communication part, can be also located on a remote site (e.g. a radio head or a radio station etc.). It is to be noted that in the present specification processing portions should not be only considered to represent physical portionsof one or more processors, but may also be considered as a logical division of the referred processing tasks performed by one or more processors. It should be appreciated that according to some examples, a so-called “liquid” or flexible network concept may be employed where the operations and functionalities of a network element, a network function, or of another entity of the network, may be performed in different entities or functions, such as in a node, host or server, in a flexible manner. In other words, a “division of labor” between involved network elements, functions or entities may vary case by case.

[0176] The present disclosure generally seeks to provide a solution for leveraging application awareness regarding error correction characteristics (e.g., the forward-error-correction, FEC, characteristics) to enhance RLC retransmissions, with new triggers for timely retransmissions and also conditions to stop unnecessary retransmission.

[0177] In particular, the present disclosure proposes devices / sy stems and methods able to achieve the RLC re-transmission related enhancements, including avoiding unnecessary retransmissions and timely autonomous retransmissions. Compared to the existing technique / approach, the proposed devices / systems and methods can meet both the requirements at the same time.

[0178] The present disclosure especially aims at providing high reliability for XR (i.e., Extended Reality) data transmissions. The objective is to enhance the RLC retransmissions to react in a timely manner to start retransmissions early enough and also stop retransmissions once they do not provide any gains or any additional information. With availability of error correction information (e.g., the FEC characteristics) at the RAN, the mechanisms for communications between a UE and a network node (e.g., a gNB) can be improved even further to enhance efficiency.

[0179] The topic regarding enhanced RLC retransmissions is currently under study in release-19 (Rel-19) proposals. As proposed in Rel-19 work item proposal for XR in RP -240647, new enhancements are suggested to leverage application awareness in radio access networks (RAN). Among them, knowledge from application regarding error correction (e.g., FEC) information of the video codec can be used to adjust RAN operations for better performance. Fig. 1 schematically illustrates an example of FEC based discard (taking into account inter- PDU set dependency) as proposed in Rel-19 for implementations of XR and Media services (XRM). As proposed in RP -233317, taking the I / P frames-based video codec as an example, in case with FEC at application layer, then not all P-frames are needed for a decodable video frameat application layer. In the example as shown in Fig. 1, the PDU set #1 is decodable in case less than 1 / 3 of the P-frames are discarded.

[0180] Approaches of radio link control (RLC) enhancements as proposed in XR Rel-19 is directed at “RLC re-transmission related enhancements for operation of RLC Acknowledged Mode (AM) with small packet delay budget” (see RP -240791). In particular, it is defined in RAN2 #126 the following:Avoiding unnecessary retransmissions• For avoiding unnecessary RLC AM retransmissions, RAN2 to enhance the RLC AM by adopting enhancements from one of the following perspectives:1. Rx initiated approach2. Tx initiated approach• RAN2 will discuss details of both approaches, compare them and choose one once the details are clearer.• For Tx initiated approach:• The transmitting side of AM RLC entity notifies the receiving RLC side about the obsolete Service Data Units (SDUs)• Tx side stops retransmit obsolete SDUs• Rx side updates state variables according to the information from Tx side• For Rx initiated approach:• For proper advancing of the transmitting window, RLC AM is enhanced with a way for the receiver to indicate abandoned SDUs to the transmitter.• Tx side just processes the status report as in legacy• FFS how Rx side determines that an SDU should be abandonedAutonomous retransmissions• To achieve timely retransmissions on RLC layer for XR traffic, RAN2 will consider the following options:• Autonomous retransmission (i.e. without status report) of PDUs based on some triggers (existing or new triggers can be considered)• Retransmission based on enhanced status report• Retransmission based on enhanced pollingFFS whether any enhancements are needed or this can be solved with proper configuration and current mechanism• Impact on capacity should be considered• RAN2 focuses on the enhancements for UL traffic

[0181] For XR services, one of the main challenges is the short packet delay budget (PDB), usually in the order of 10-30 ms, and thus the RLC has to be able to trigger the retransmissions (if needed) as soon as possible and stop them once the packets cannot be sent within PDB. In order to enable these enhancements, new set of rules are required to trigger timely retransmission and stop them accordingly.

[0182] With access to the error correction (e.g., FEC) information at RAN, better Radio Resource Management (RRM) decisions can be made, depending on the current state of decodability of an application data unit (e.g., video slice, audio, image, etc.). For instance, if the RAN becomes aware that sufficient data has been delivered from a PDU set, it may change the way it will handle the remaining packets of the same PDU set (assuming each data unit corresponds to a PDU set). Similarly, if the RAN knows that the receiver has not received enough packets for recovery / decoding of a PDU set (or application data unit), it may react in a timely manner to make sure the following data arrives correctly before the packet delay budget (PDB) and / or packet set delay budget (PSDB) is exceeded.

[0183] Accordingly, in order to guarantee high reliability for XR data transmissions, the present disclosure aims at providing an improved solution for enhanced RLC retransmissions. It is proposed to enhance the RLC retransmissions by reacting in a timely manner to start retransmissions early enough and, at the same time, by reducing or stopping retransmissions once they do not provide any gains or any additional information. As described below, based on error correction characteristics such as FEC information provided at the RAN, the proposed mechanisms allow for improving wireless network systems with enhanced efficiency.

[0184] In other words, the present disclosure provides solutions to leverage application awareness regarding the error correction (e.g., FEC) characteristics to enhance RLC retransmissions to improve efficiency without sacrificing reliability. The enhancements target new triggers for timely retransmissions and also conditions to reduce / stop unnecessary retransmission.

[0185] With the assumption that the error correction (e.g., FEC) characteristics of the application is known at the RAN side, it is proposed to introduce an adaptive RLCacknowledged mode (AM) scheme based on application layer information (e.g., the error correction characteristics) which can help to reduce useless Automatic Repeat Request (ARQ) retransmissions (reTx) or to trigger timely ARQ retransmissions to increase the probability of successful decoding (e.g., when some data packets are lost).

[0186] In more detail, for the PDUs in the same PDU Set, the triggers for retransmissions, the maximum number of retransmissions (#reTx) and conditions to stop (or reduce) retransmissions may be changed based on the PDUs reception status of the PDU Set. For example, as long as FEC conditions are not fulfilled (i.e., not enough information is delivered for a successful packet decoding), the RLC AM may follow a more “conservative” policy on triggering retransmissions more often (e.g., with a higher retransmission rate). Once the transmitter makes sure (or is aware) that an application data unit is most likely decodable at the receiver, the RLC AM may enter a more “aggressive” regime that either stops initiating new retransmissions or changes the reTx trigger conditions (e.g., to retransmit the data units less often with a lower retransmission rate).

[0187] According to embodiments of the present disclosure, the following practical examples for retransmission schemes (i.e., policies) may be considered:

[0188] Embodiment A:It is assumed that a K-out-of-N FEC scheme is used (i.e., the application requires successful decoding of K PDUs out of N PDUs), as one example, the proposed adaptive RLC AM may have a retransmission policy as follows:- For the first K out of N PDUs, the RLC AM policy= “conservative” is used, which sets the #reTx = 1 (or a preconfigured number R_c), and which enables a new set of triggers for the RLC retransmissions. These triggers may include (but are not limited to): o A timer-based trigger: after a preconfigured time T since an RLC SDU has been submitted to a lower layer, an RLC retransmission will be initiated regardless of its delivery status. o A shorter T-reassembly timer (and / or a T-PollRetransmit timer, a T- StatusProhibit timer, etc.): a second value for the T-reassembly T_c may be configured to have a smaller value than the initial (default) T-reassembly timerT_R value (T_c < T_R), which triggers status reports earlier than the default configuration.■ A blind retransmission trigger: a probability condition such as “flipping a coin” (with probability P to initiate a retransmission and 1-P to not initiate a blind retransmission) may be defined in which for each PDU the transmitter may generate a random number and based on the threshold probability P, it may trigger a blind retransmission. In an extreme case, the RLC retransmission may be enabled for the first K PDUs (i.e., P=l).- For each of the following PDUs, the RLC AM policy= “conservative” is used by default unless K out of N PDUs are received. When K out of N PDUs are successfully delivered, RLC AM policy= “aggressive” is used since the packet loss of the (N-K) packets does not affect the successful decoding of the PDU Set. In other words, this policy may set the #reTx = 0 (or a preconfigured number R_a), and may disable the new sets of triggers for RLC retransmissions that were in place while “conservative” mode was active. Furthermore, any ongoing RLC retransmissions may be terminated immediately, either with an indication to the receiver or without it. For the case without an indication of the RLC retransmission termination, the receiver may rely on the configurations of the “aggressive” policy to an understanding that once this policy is activated, all ongoing (expected) RLC retransmissions may be cancelled.

[0189] It is noted that the above indicated blind retransmission trigger may be a supplementary option (as a subset of shortening T-reassembly timer item) as a way to trigger new retransmissions without a need for explicit feedback of what has happened at the receiver. The configurability of the P parameter may provide extra protection before satisfying the K- out-of-N condition, which may then be stopped / terminated by relaxing to P=l. Since it is not necessary to wait for the feedback, the system may thus be unaware of the exact missing RLC SDUs. Furthermore, even for the RLC where no explicit ACK / NACK per PDU is sent, the receiver may indicate the delivered RLC PDU(s) and which RLC PDU(s) has not been delivered based on a status report.

[0190] Embodiment B:In an alternative example, the FEC condition (i.e., whether or not enough information is delivered for a successful packet decoding) may be configured to adapt only when a certain amount of data (e.g., number of bytes) have been successfully delivered. For example, if the size of a PDU Set is B, then the condition may be defined by splitting / dividing the whole PDU Set in “classes” of size: 0 < Bl < B2 < B. At any time, this policy may take different decisions depending on the amount of bytes that have been delivered successfully (e.g., 0 < Bs < B) and the minimum amount of bytes that need to be delivered successfully to recover the PDU Set (e.g., Bmin < B, here Bmin may be equal to B2 since the FEC condition may require to have more than Bmin data units to be delivered). For example, the RLC AM policy= “conservative” is used until B2 is successfully delivered and then the RLC AM policy= “aggressive” is used otherwise. In another example, two different configurations of the conservative mode may be configured (with different R_c, T_c and P values as explained in Embodiment A), namely, “coni” and “con2”. Thus, for the successfully transmitted size X where 0 <X< Bl, the RLC AM policy= “coni” is used, while for the transmitted successfully size Y where Bl< Y < B2 (B2=Bmin), the RLC AM policy= “con2” is used, and then the RLC AM policy= “aggressive” may be used otherwise.

[0191] Embodiment C:In another example, instead of indicating of a number of data units (e.g., K or N), a percentage value of F may be indicated via the application to inform if F% of the total size of a PDU set or application data unit is delivered, and the receiver side will then be able to recover the original information. Thus, as long as F% of PDUs are not successfully delivered, the RLC AM policy= “conservative” is used and vice versa, afterwards the RLC AM policy= “aggressive” may be used, for example.

[0192] Embodiment D:In another example, the RLC AM policy = “aggressive” is simply set to no RLC ARQ, in which the RLC may stop the ongoing and future RLC retransmissions for the current PDU set or application data unit packets. This can also be interpreted as using FEC knowledge (in the transmitter or receiver) as a new trigger to avoid unnecessary retransmissions.

[0193] Embodiment E:In another example, considering that the K-out-of-N FEC scheme is used, a “conservative” ARQ policy is used for the first K packets with the intention to get the K packets received correctly (i.e., successfully delivered). It could happen that still some packets (among these K packets) do not go through (i.e., successfully delivered). In this case an even more conservative ARQ retransmission policy may be applied to the remaining N-K packets.

[0194] According to the present disclosure, a “conservative” policy may refer to a retransmission scheme that applies RLC parameters associated with a higher retransmission rate compared to an “aggressive” policy. Accordingly, changing the retransmission scheme from a “conservative” policy to an “aggressive” policy may mean to decrease the retransmission rate, while changing the retransmission scheme from an “aggressive” policy to a “conservative” policy may mean to increase the retransmission rate.

[0195] Although the foregoing embodiments are provided referring explicitly to FEC characteristics as an example, other possible error correction information (e.g., backward error correction) is feasible and within the scope of the present disclosure.

[0196] References are now made to the figures. In particular, it is to be noted that identical or like reference numbers used in the figures of the present disclosure may, unless indicated otherwise, indicate identical or like elements, such that repeated description thereof may be omitted for reasons of conciseness.

[0197] In the following, the proposed devices / methods according to the present disclosure will be explained separately for the cases of downlink (DL) and uplink (UL).Downlink Retransmission Procedure

[0198] Fig. 2 schematically illustrates an example of a signaling diagram for a downlink RLC retransmission process according to an example embodiment of the present disclosure.

[0199] As illustrated in Fig. 2, the network node (e.g., gNB) and the UE both support an ARQ process when communicating with each other. In particular, the communication between the network node and the UE may be based on configuration information that includes a plurality of RLC parameters for controlling RLC retransmissions in the ARQ process. As indicated above, the plurality of RLC parameters may include at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parametersassociated with a second retransmission rate lower than the first retransmission rate. A step- wise description of the diagram is as follows.

[0200] At step S201 : the gNB configures the UE with new FEC-based RLC AM policies regarding how to react to these policies. As an example, two possible policies are “conservative” (e.g., policy A) and “aggressive” (e.g., policy B). Each of the policies may have its own set of parameters (e.g., RLC parameters), such as the number of retransmissions, retransmission timer, T-reassembly timer (and / or a T-PollRetransmit timer, a T-StatusProhibit timer, etc.) and the probability for the blind retransmission trigger. It should be noted that the above listed RLC parameters are non-limiting examples, and other RLC parameters may also be taken into account in practical implementations.

[0201] At step S202: the gNB is informed by core network (CN) entities, such as Application Function (AF), Session Management Function (SMF), and / or User plane function (UPF), about a certain FEC configuration for PDU sets in a QoS flow or a PDU session. This condition may be similar to the example described above for a K-out-of-N type of FEC method used at the application layer. Additionally, the UE may obtain the FEC configuration information via the CN entities as well.

[0202] At step S203 : a PDU set with the aforementioned FEC configuration arrives at the gNB.

[0203] At step S204: the gNB chooses the configuration parameters specified for policy A for the first part of the PDU set data transmission. This policy may emphasize on reliability other than resource efficiency (e.g., based on a higher retransmission rate).

[0204] At step S205: the gNB sends an indication to the UE to activate policy A from the set of policies configured in step S201. The indication can be carried via an RLC control PDU or other Layer-2 (L2) signaling e.g., the MAC control element (CE).

[0205] At step S206: the UE processes the gNB’s indication and configures its local RLC AM parameters to those listed for policy A.

[0206] At step S207: the gNB carries on with (re-)transmissions of data in DL following policy A configurations.

[0207] At step S208: the UE realizes that at least one RLC SDU is lost (based on configuration of policy A) and sends a status report to inform the gNB of the sequence number (SN) of the missing SDU(s).

[0208] At step S209: the gNB retransmits the indicated missing SDU(s) or gNB retransmits the SDUs without waiting for the RLC status report according to policy A e.g., based on the blind retransmission probability.

[0209] At step S210: the condition of step S202 is met (i.e., enough data for decoding the PDU set has been delivered).

[0210] At step S211 : the gNB reacts to the FEC condition satisfaction and changes the RLC AM to use policy B. This policy may emphasize on resource efficiency (e.g., based on a lower retransmission rate).

[0211] At step S212: the gNB sends an indication to the UE to activate policy B from the set of policies configured in step S201. The indication can be carried via an RLC control PDU or other L2 signaling. In another embodiment, this indication can also be used to let the UE know that the expected RLC retransmission(s) will discontinue and the UE should not expect those RLC SNs. It should be noted that this step is optional, since the UE may also know that the policy is changed from A to B for the remaining PDUs when it received first K PDUs from the gNB based on the FEC configuration information (i.e., K-out-of-N) obtained from the CN entities, as mentioned in step S201 above.

[0212] At step S213: the UE processes the gNB’s indication and configures its local RLC AM parameters to those listed for policy B. Similar to the point made in the previous step, the UE may update its reception RLC window, knowing that some of the RLC SNs are not expected to be received.

[0213] At step S214: the gNB carries on with (re-)transmissions of data in DL following policy B configurations until the transmission of the PDU set is finished.

[0214] It may be noted that in some implementations, the indication in step S212 may be skipped and instead new rules can be defined in step S201 for autonomous changing of policy at the UE side. These rules clarify for the UE that after reception of a certain percentage of the PDUs (e.g., based on the K-out-of-N condition) the retransmission scheme should switch to another predefined policy (e.g., policy B).

[0215] Accordingly, upon reception of indications to change policies (or the reception of PDUs and FEC configuration information in case the reception of the indications is not necessarily required), the UE may update its RLC AM configuration parameters. For example, the UE may update the reception window accounting for the RLC SDUs that are not expected to be received after the policy change. In other words, the UE may update the configurationparameters / reception window depending on the explicit indications from the gNB or the configuration and reception status of the PDUs.

[0216] It is noted that the foregoing embodiment referring explicitly to FEC characteristics (e.g., FEC-based RLC AM policies, FEC configurations, FEC conditions, etc.) is a non-limiting example of criteria which can be used for enhancing RLC retransmissions. It is appreciated that other types of error correction (e.g., backward error correction) are feasible and within the scope of the present disclosure. Moreover, although the foregoing embodiment is directed at changing the retransmission policy from “conservative” to “aggressive”, i.e., decreasing the retransmission rate, it is to be understood that changing the retransmission policy in the other direction (i.e., from “conservative” to “aggressive” that increases the retransmission rate) is also applicable under the scope of the present disclosure.Uplink Retransmission Procedure

[0217] In UL, two implementations can be considered:• Dynamic case: the UE sends an indication (e.g., the MAC CE) per each PDU set (or application data unit) to inform that enough data has been sent and the rest of the PDU set can be handled differently.• Semi-static case: the FEC characteristics are sent once and the gNB may keep track of the delivery rate.

[0218] Fig. 3 schematically illustrates an example of a signaling diagram for an uplink RLC retransmission process according to an example embodiment of the present disclosure. Herein, the scenario for dynamic indication case is illustrated.

[0219] As illustrated in Fig. 3, the network node (e.g., gNB) and the UE both support an ARQ process when communicating with each other. Similar to the above described downlink case, the communication between the network node and the UE may be based on configuration information that includes a plurality of RLC parameters for controlling RLC retransmissions in the ARQ process. Besides, the plurality of RLC parameters may include at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate. A step- wise description of the diagram is as follows.

[0220] At step S301 : the gNB configures the UE with new FEC-based RLC AM policies regarding how to react to these policies. As an example, two possible policies are “conservative” (e.g., policy A) and “aggressive” (e.g., policy B). Each of the policies may haveits own set of parameters (e.g., RLC parameters), such as the number of retransmissions, retransmission timer, T-reassembly timer (and / or a T-PollRetransmit timer, a T-StatusProhibit timer, etc.) and the probability for the blind retransmission trigger. It should be noted that the above listed RLC parameters are non-limiting examples, and other RLC parameters may also be taken into account in practical implementations.

[0221] At step S302: the gNB configures the mapping of a PDU set to the QoS flow to a logical channel (LCH).

[0222] At step S303: the UE (and / or the gNB) is informed by core network (CN) entities such as Session Management Function (SMF) about a certain FEC configuration for PDU sets in a QoS flow or a PDU session. This condition may be similar to the example described above for a K-out-of-N type of FEC method used at the application layer. In another embodiment, the UE may inform directly the gNB about the FEC configuration using the Radio resource control (RRC) UE Assistance Information (UAI) framework. The UAI framework is therefore extended to convey assistance information regarding the FEC configuration.

[0223] At step S304: a PDU set with the aforementioned FEC configuration arrives at the UE buffer.

[0224] At step S305: the UE sends an indication informing the gNB that certain RLC AM processes may carry the data from a PDU set that requires FEC-based handling configured in step S301. Also, the UE may at the same time indicate the activation of policy A for the aforementioned RLC AM processes. This policy may emphasize on reliability other than resource efficiency (e.g., based on a higher retransmission rate).

[0225] At step S306: the gNB processes the UE’s indication and configures its local RLC AM parameters to those listed for policy A.

[0226] At step S307: the UE carries on with (re-)transmissions of data in UL following policy A configurations.

[0227] At step S308: the gNB realizes that at least one RLC SDU is lost (based on configuration of policy A) and sends a status report to inform the UE of the sequence number (SN) of the missing SDU(s).

[0228] At step S309: the UE retransmits the indicated missing SDU(s).

[0229] At step S310: the condition of step S303 is met (i.e., enough data for decoding the PDU set has been delivered).

[0230] At step S311 : the UE reacts to the FEC condition satisfaction and changes the RLC AM to use policy B. This policy may emphasize on resource efficiency (e.g., based on a lower retransmission rate).

[0231] At step S312: the UE sends an indication to the gNB to activate policy B from the set of policies configured in step S301. The indication can be carried via an RLC control PDU. In another embodiment, this indication can also be used to let the gNB know that the expected RLC retransmission(s) will discontinue and the gNB should not expect those RLC SNs. It should be noted that this step is optional, since, in the semi-static case, the gNB may also track the condition of the delivery rate to determine whether enough data has been received or not.

[0232] At step S313: the gNB processes the UE’s indication and configures its local RLC AM parameters to those listed for policy B. Similar to the point made in the previous step, the gNB may update its reception RLC window, knowing that some of the RLC SNs are not expected to be received.

[0233] At step 314: The UE carries on with (re-)transmissions of data in UL following policy B configurations until the transmission of the PDU set is finished.

[0234] It may be noted that the UE may provide an indication of having data in buffer that required FEC -based handling, and another indication upon expected satisfaction of the FEC criteria (i.e., once enough data has been delivered). Similar to the DL case, upon reception of indications to change policies (or the reception of PDUs and FEC configuration information in case the reception of the indications is not necessarily required), the gNB may also update its RLC AM configuration parameters accordingly.

[0235] It should be further noted that the above described example as illustrated in Fig. 3 refers to the dynamic indication case. For the semi-static case, the operations may be very similar to the dynamic case, except for:• In step S303 above, the gNB may get a semi-static from the UE of the FEC condition (e.g., the K-out-of-N type of condition or proportion-based condition that for example X% of total PDU set size reception is enough for decoding).• In step S312: the dynamic indication is not needed as the gNB may keep track of the delivery rate condition specified above to determine if enough data has been received or not.

[0236] It may be noted that in some implementations (such as the above mentioned semistatic case), the indication in step S312 may be skipped, and instead, autonomous changing ofpolicy may take place at the gNB side based on the tracking information regarding whether the received data units meet the predetermined threshold for successfully decoding a data unit set.

[0237] By exploiting the information available at RAN regarding the FEC characteristics of the data at the application layer, the proposed RLC AM mechanisms can be adjusted to• First, make sure reliable data transmission is established to satisfy any FEC-based requirements to ensure seamless user experience, which may help to trigger timely RLC retransmissions.• Second, upon satisfaction of such FEC-based requirements, the resources can be released (e.g., with more aggressive transmission policies) to enhance spectral efficiency with minimum impact on the user’s quality of experience, which may help to stop unnecessary RLC retransmissions.

[0238] In summary, the present disclosure provides a solution for leveraging application awareness regarding the FEC characteristics to enhance RLC retransmissions, with new triggers for timely retransmissions and also conditions to stop unnecessary retransmission. In particular, RLC re-transmission related enhancements are proposed, including both avoiding unnecessary retransmissions and timely autonomous retransmissions, which may be achieved by one or more of the following technical features:For UL (and DL is similar with swap between UE and gNB):• UE communicates to the gNB the capability to support FEC-aware RLC policy switching• gNB enables and configures UE with the new FEC-based RLC policies for RLC retransmission, where the policies are defined by RLC-related parameters• gNB configures the mapping of PDU set to QoS flow to LCH and UE is informed of the FEC configuration for PDU sets in the QoS flow• UE indicates gNB the FEC-based handling for the RLC AM processes carrying the data from a PDU set and the activation of policy A for the RLC AM processes.• gNB configures its local RLC AM parameters to those listed for policy A• UE (re)transmits data in UL and gNB processes the RLC AM both following policy A configurations• UE determines that enough data for decoding the PDU set has been delivered based on the informed FEC configuration• UE changes the RLC AM to use policy B to react the determination• UE sends an indication to the gNB to activate policy B.• UE (re)transmits left data and gNB processes the RLC AM procedure both following policy B configurationsAccordingly, the UE / gNB may determine policies based on the FEC configuration, which adjusts the parameters for RCL AM processes (such as RCL AM retransmission).

[0239] Additionally, the present disclosure further proposes one or more of the following explementary implementations (for UL, and DL is similar with swap between UE and gNB):• the gNB (or UE for DL case) is also informed of the FEC configuration and changes the policy for RLC AM automatically (without indication from UE) based on the informed FEC configuration and the reception of PDUs• the determination in step S310 is based on the successful delivery of one of the following: a certain (percentage of) number of PDUs, a certain amount of data (e.g. number of bytes), or a certain percentage value of total size of PDU set• the parameters include at least one of the following: maximum number of reTx, a preconfigured time T for trigger the retransmission, T-reassembly timer, a probability P for blind reTx trigger• policy B is set without T and P, and / or longer T-reassembly timer, and / or smaller maximum number of reTx, or just simply set to no RLC ARQ• the indication in step S312 can be carries via a RLC control PDU• the indication in step S312 can also be used to inform the gNB (or UE for DL case) that the expected RLC reTx will discontinue and it should not expect those RLC SNs• the capability to support FEC-aware RLC policy switching is o the capability to support UE-autonomous FEC-aware RLC policy switching based on at least a determination policy o the capability to support gNB-controlled FEC-aware RLC policy switching based on an indication signaled by the gNB

[0240] It is appreciated that the proposed solution may allow for, in the UL case, the change of policy to be informed by an indication from the UE (dynamic case), or automatic change of policy without an indication (semi-static case). Specifically, the present disclosureproposes the FEC-based RLC handling which leads to changes in RLC polices, where policy A is used to trigger timely retransmissions while policy B is used to reduce or stop unnecessary retransmissions, for example. In this way, the proposed solution may result in improved user experience and improved resource utilization / reduced power consumption.

[0241] It is noted that the foregoing embodiment referring explicitly to FEC characteristics (e.g., FEC-based RLC AM policies, FEC configurations, FEC conditions, etc.) is a nonlimiting example of criteria which can be used for enhancing RLC retransmissions. It is appreciated that other types of error correction (e.g., backward error correction) are feasible and within the scope of the present disclosure. Moreover, although the foregoing embodiment is directed at changing the retransmission policy from “conservative” to “aggressive”, i.e., decreasing the retransmission rate, it is to be understood that changing the retransmission policy in the other direction (i.e., from “conservative” to “aggressive” that increases the retransmission rate) is also applicable under the scope of the present disclosure.

[0242] Fig. 4 illustrates an example of a method 400 of a UE for controlling RLC retransmissions in an Automatic Repeat Request (ARQ) process in accordance with embodiments of the disclosure. Method 400 can be performed by any suitable device / apparatus (e.g., mobile devices, computers, etc.) comprising any suitable means for performing method 400. In particular, method 400 may be implemented during communications between the UE and a network node of a radio access network in accordance with configuration information, as described in the embodiment of Fig. 2, for example.

[0243] As indicated above, the configuration information may include a plurality of RLC parameters for controlling RLC retransmissions in the ARQ process. Also, the plurality of RLC parameters may comprise at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate distinct from the first retransmission rate.

[0244] At step S401, method 400 comprises receiving, from the network node, one or more data units of a data unit set using the first set of RLC parameters.

[0245] At step S402, method 400 comprises receiving, from the network node, one or more remaining data units of the data unit set using the second set of RLC parameters. It should benoted that this step may take place in response to the determination whether or not the received one or more data units of the data unit set meets a predetermined threshold as indicated by error correction characteristics for successfully decoding the data unit set.

[0246] It is noted that, in some implementations, the second retransmission rate may be lower than the first retransmission rate, i.e., method 400 may decrease the retransmission rate, in case that it is determined that the received one or more data units of the data unit set meets the predetermined threshold. On the other hand, in other implementations, the second retransmission rate may be higher than the first retransmission rate, i.e., method 400 may increase the retransmission rate, in case that it is determined that the received one or more data units of the data unit set does not meet the predetermined threshold.

[0247] Fig. 5 illustrates an example of a method 500 of a network node of a radio access network for controlling RLC retransmissions in an Automatic Repeat Request (ARQ) process in accordance with embodiments of the disclosure. Method 500 can be performed by any suitable device / apparatus (e.g., a base station, gNB, etc.) comprising any suitable means for performing method 500. In particular, method 500 may be implemented during communications between the network node and a UE, as described in the embodiment of Fig. 2, for example.

[0248] At step S501, method 500 comprises configuring the UE with a configuration message for controlling a radio link between the network node and the UE. The configuration message may include a plurality of RLC parameters for controlling RLC retransmissions in the ARQ process. Besides, the plurality of RLC parameters may include at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate distinct from the first retransmission rate.

[0249] At step S502, method 500 comprises transmitting, to the UE, one or more data units of a data unit set using the first set of RLC parameters.

[0250] At step S503, method 500 comprises determining, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, whether or not the transmitted one or more data units of the data unit set meets the predetermined threshold.

[0251] At step S504, method 500 comprises transmitting, to the UE, one or more remaining data units of the data unit set using the second set of RLC parameters in response to the determination.

[0252] It is noted that, in some implementations, the second retransmission rate may be lower than the first retransmission rate, i.e., method 500 may decrease the retransmission rate, in case that it is determined that the received one or more data units of the data unit set meets the predetermined threshold. On the other hand, in other implementations, the second retransmission rate may be higher than the first retransmission rate, i.e., method 500 may increase the retransmission rate, in case that it is determined that the received one or more data units of the data unit set does not meet the predetermined threshold.

[0253] Fig. 6 illustrates an example of a method 600 of a UE for controlling RLC retransmissions in an Automatic Repeat Request (ARQ) process in accordance with embodiments of the disclosure. Method 600 can be performed by any suitable device / apparatus (e.g., mobile devices, computers, etc.) comprising any suitable means for performing method 600. In particular, method 600 may be implemented during communications between the UE and a network node of a radio access network in accordance with configuration information, as described in the embodiment of Fig. 3, for example.

[0254] As indicated above, the configuration information may include a plurality of RLC parameters for controlling RLC retransmissions in the ARQ process. Also, the plurality of RLC parameters may comprise at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate distinct from the first retransmission rate.

[0255] At step S601, method 600 comprises transmitting, to the network node, one or more data units of a data unit set using the first set of RLC parameters.

[0256] At step S602, method 600 comprises determining, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, whether or not the transmitted one or more data units of the data unit set meets the predetermined threshold.

[0257] At step S603, method 600 comprises transmitting, to the network node, one or more remaining data units of the data unit set using the second set of RLC parameters in response to the determination.

[0258] It is noted that, in some implementations, the second retransmission rate may be lower than the first retransmission rate, i.e., method 600 may decrease the retransmission rate, in case that it is determined that the received one or more data units of the data unit set meets the predetermined threshold. On the other hand, in other implementations, the second retransmission rate may be higher than the first retransmission rate, i.e., method 600 may increase the retransmission rate, in case that it is determined that the received one or more data units of the data unit set does not meet the predetermined threshold.

[0259] Fig. 7 illustrates an example of a method 700 of a network node of a radio access network for controlling RLC retransmissions in an Automatic Repeat Request (ARQ) process in accordance with embodiments of the disclosure. Method 700 can be performed by any suitable device / apparatus (e.g., a base station, gNB, etc.) comprising any suitable means for performing method 700. In particular, method 500 may be implemented during communications between the network node and a UE, as described in the embodiment of Fig. 3, for example.

[0260] At step S701, method 700 comprises configuring the UE with a configuration message for controlling a radio link between the network node and the UE. The configuration message may include a plurality of RLC parameters for controlling RLC retransmissions in the ARQ process. Besides, the plurality of RLC parameters may include at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate distinct from the first retransmission rate.

[0261] At step S702, method 700 comprises receiving, from the UE, one or more data units of a data unit set using the first set of RLC parameters.

[0262] At step S703, method 700 comprises receiving, from the UE, one or more remaining data units of the data unit set using the second set of RLC parameters, in response to the determination whether or not the received one or more data units of the data unit set meets a predetermined threshold as indicated by one or more error correction characteristics for successfully decoding the data unit set.

[0263] It is noted that, in some implementations, the second retransmission rate may be lower than the first retransmission rate, i.e., method 700 may decrease the retransmission rate, in case that it is determined that the received one or more data units of the data unit set meets the predetermined threshold. On the other hand, in other implementations, the second retransmission rate may be higher than the first retransmission rate, i.e., method 700 may increase the retransmission rate, in case that it is determined that the received one or more data units of the data unit set does not meet the predetermined threshold.

[0264] In view of the above, the present disclosure provides a solution for leveraging application awareness regarding the FEC characteristics to enhance RLC retransmissions, with new triggers for timely retransmissions and also conditions to stop unnecessary retransmission. It is appreciated that the proposed solution ensures reliable data transmission to satisfy any FEC-based requirements for seamless user experience. On the one hand, it is allowed RLC retransmissions to be timely triggered (e.g., with more conservative transmission policies) in case that the required FEC condition is not fulfilled. On the other hand, upon satisfaction of such FEC-based requirements, the resources can be released (e.g., with more aggressive transmission policies) to enhance spectral efficiency. Accordingly, unnecessary RLC retransmissions may be stopped / terminated with minimum impact on the user’s quality of experience.

[0265] It is noted that, although in the above-illustrated example embodiments (with reference to the figures), the messages communi cated / exchanged between the network components / elements may appear to have specific / explicit names, depending on various implementations (e.g., the underlining technologies), these messages may have different names and / or be communi cated / exchanged in different forms / formats, as can be understood and appreciated by the skilled person.

[0266] According to some example embodiments, there are also provided corresponding methods suitable to be carried out by the apparatuses (network elements / components) as described above, such as the UE, the CU, the DU, etc.

[0267] It should nevertheless be noted that the apparatus (device) features described above correspond to respective method features that may however not be explicitly described, for reasons of conciseness. The disclosure of the present document is considered to extend also to such method features. In particular, the present disclosure is understood to relate to methods ofoperating the devices described above, and / or to providing and / or arranging respective elements of these devices.

[0268] Further, according to some further example embodiments, there is also provided a respective apparatus (e.g., implementing the UE, the CU, the DU, etc., as described above) that comprises at least one processing circuitry, and at least one memory for storing instructions to be executed by the processing circuitry, wherein the at least one memory and the instructions are configured to, with the at least one processing circuitry, cause the respective apparatus to at least perform the respective steps as described above.

[0269] Yet in some other example embodiments, there is provided a respective apparatus (e.g., implementing the UE, the CU, the DU, etc., as described above) that comprises respective means configured to at least perform the respective steps as described above.

[0270] It is to be noted that examples of embodiments of the disclosure are applicable to various different network configurations. In other words, the examples shown in the above described figures, which are used as a basis for the above discussed examples, are only illustrative and do not limit the present disclosure in any way. That is, additional further existing and proposed new functionalities available in a corresponding operating environment may be used in connection with examples of embodiments of the disclosure based on the principles defined.

[0271] It should also to be noted that the disclosed example embodiments can be implemented in many ways using hardware and / or software configurations. For example, the disclosed embodiments may be implemented using dedicated hardware and / or hardware in association with software executable thereon. The components and / or elements in the figures are examples only and do not limit the scope of use or functionality of any hardware, software in combination with hardware, firmware, embedded logic component, or a combination of two or more such components implementing particular embodiments of the present disclosure.

[0272] It should further be noted that the description and drawings merely illustrate the principles of the present disclosure. Those skilled in the art will be able to implement various arrangements that, although not explicitly described or shown herein, embody the principles of the present disclosure and are included within its spirit and scope. Furthermore, all examples and embodiment outlined in the present disclosure are principally intended expressly to be only for explanatory purposes to help the reader in understanding the principles of the proposed method. Furthermore, all statements herein providing principles, aspects, and embodiments ofthe present disclosure, as well as specific examples thereof, are intended to encompass equivalents thereof.List of abbreviations:ACK AcknowledgementLDPC low density parity checkTB Transport blockUE User equipmentRRC Radio Resource ControlTB transport block reTx retransmissionFEC forward error correctionMAC medium access controlHARQ hybrid automatic repeat requestMCS modulation and coding schemeLCH / G logical channel / channel groupBSR buffer status reportSMF Session Management FunctionUPF User plane functionBBU Baseband UnitREC Radio Equipment ControllerRCC Radio Cloud Center?C-RAN Cloud Radio Access NetworkV-RAN Virtualized RAN0-RAN Open RAN

Claims

CLAIMS1. A User Equipment, UE, configured to support an Automatic Repeat Request, ARQ, process when communicating with a network node of a radio access network in accordance with configuration information; wherein the configuration information includes a plurality of Radio Link Control, RLC, parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate, the UE comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the UE at least to: receive, from the network node, one or more data units of a data unit set using the first set of RLC parameters; and in response to a determination, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the received one or more data units of the data unit set meets the predetermined threshold, receive, from the network node, one or more remaining data units of the data unit set using the second set of RLC parameters.

2. The UE according to claim 1, wherein the first set of RLC parameters defines a first retransmission policy enabling the first retransmission rate and the second set of RLC parameters defines a second retransmission policy enabling the second retransmission rate, wherein the UE is further caused to select the second retransmission policy for receiving the one or more remaining data units of the data unit set in response to the determination.

3. The UE according to claim 1 or 2, wherein the predetermined threshold to be met comprises a required amount of data to be received by the UE for successfully decoding the data unit set, and the determination comprises determining that a received amount of data which has been received by the UE fulfills the required amount of data, and optionally, wherein the received amount of data which has been received by the UE comprises at least one of thefollowing: a certain number or percentage of data units within the data unit set, a certain number of bytes within the data unit set, or a certain percentage value of total size of the data unit set.

4. The UE according to any one of claims 1 to 3, wherein the UE is further caused to receive, from the network node, a configuration message including the configuration information for controlling a radio link between the UE and the network node, and optionally, wherein the plurality of RLC parameters comprises at least one of the following: a maximum number of retransmissions, a preconfigured time for triggering a retransmission, a T-reassembly timer, a T-PollRetransmit timer, a T-StatusProhibit timer, or a probability for triggering a blind retransmission.

5. The UE according to claim 4, wherein, for defining the second retransmission policy, the second set of RLC parameters is set based on one or more of the following: increasing a duration of one or more of the T-reassembly timer, the T-PollRetransmit timer and the T-StatusProhibit timer, reducing the maximum number of retransmissions, disabling the preconfigured time for triggering a retransmission and / or the probability for triggering a blind retransmission, and deactivating sending of an RLC ARQ to terminate ongoing retransmissions.

6. The UE according to any one of claims 2 to 5, wherein, prior to the receiving one or more data units of the data unit set using the first set of RLC parameters, the UE is further caused to: configure, based on a received first activation indication to activate the first retransmission policy, the plurality of RLC parameters to the first set of RLC parameters.

7. The UE according to claim 6, wherein the first activation indication is carried via an RLC control Protocol Data Unit (PDU), or other Layer-2 signaling messages.

8. The UE according to any one of claims 2 to 7, wherein, in response to the determination that the received one or more data units of the data unit set meets the predetermined threshold, the UE is further caused to:receive, from the network node, a second activation indication to activate the second retransmission policy; and configure, based on the received second activation indication, the plurality of RLC parameters to the second set of RLC parameters.

9. The UE according to claim 8, wherein the second activation indication is carried via an RLC control Protocol Data Unit (PDU), or other Layer-2 signalling messages, and / or the second activation indication is used to inform the UE of discontinuation of expected RLC retransmissions, and, optionally, the UE is further caused to update a reception RLC window to adapt to the discontinuation of expected RLC retransmissions.

10. The UE according to any one of claims 2 to 9, wherein the UE is further caused to: receive information related to an error correction configuration indicative of the one or more error correction characteristics from an application layer; and switch, based on the received information related to the error correction configuration and a current status of data unit reception, among at least the first retransmission policy and the second retransmission policy for receiving further data units of the data unit set.

11. The UE according to claim 10, wherein the UE is further caused to communicate to the network node a capability to support error correction, EC, -aware RLC policy switching based on the received information related to the error correction configuration.

12. The UE according to claim 11, wherein the capability to support EC-aware RLC policy switching comprises one of the following: the capability to support UE-autonomous EC-aware RLC policy switching based on at least a determination policy that the received one or more data units of the data unit set meets the predetermined threshold, or the capability to support network-controlled EC-aware RLC policy switching based on an indication signaled by the network node.

13. The UE according to any one of claims 1 to 12, wherein the one or more error correction characteristics comprises forward error correction, FEC, information indicative of decodability of the data unit set specified by an application layer.

14. A network node of a radio access network, configured to support an Automatic Repeat Request, ARQ, process when communicating with a User Equipment, UE, the network node comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the network node least to: configure the UE with a configuration message for controlling a radio link between the network node and the UE, the configuration message comprising a plurality of Radio Link Control, RLC, parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate; transmit, to the UE, one or more data units of a data unit set using the first set of RLC parameters; determine, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that the transmitted one or more data units of the data unit set meets the predetermined threshold; and, in response to the determination, transmit, to the UE, one or more remaining data units of the data unit set using the second set of RLC parameters.

15. The network node according to claim 14, wherein the first set of RLC parameters defines a first retransmission policy enabling the first retransmission rate and the second set of RLC parameters defines a second retransmission policy enabling the second retransmission rate, wherein the network node is further caused to select the second retransmission policy for transmitting the one or more remaining data units of the data unit set in response to the determination.

16. The network node according to claim 14 or 15, wherein the predetermined threshold to be met comprises a required amount of data to be delivered to the UE for successfully decoding the data unit set, and the determination comprises determining that a delivered amount of data which has been delivered to the UE fulfills the required amount of data, and optionally,the delivered amount of data which has been delivered to the UE comprises at least one of the following: a certain number or percentage of data units within the data unit set, a certain number of bytes within the data unit set, or a certain percentage value of total size of the data unit set.

17. The network node according to any one of claims 14 to 16, wherein the plurality of RLC parameters comprises at least one of the following: a maximum number of retransmissions, a preconfigured time for triggering a retransmission, a T-reassembly timer, a T- PollRetransmit timer, a T-StatusProhibit timer, or a probability for triggering a blind retransmission.

18. The network node according to claim 17, wherein, for defining the second retransmission policy, the second set of RLC parameters is set based on one or more of the following: increasing a duration of one or more of the T-reassembly timer, the T-PollRetransmit timer, and the T-StatusProhibit timer, reducing the maximum number of retransmissions, disabling the preconfigured time for triggering a retransmission and / or the probability for triggering a blind retransmission, and deactivating sending of an RLC ARQ to terminate ongoing retransmissions.

19. The network node according to any one of claims 15 to 18, wherein, prior to the transmitting one or more data units of the data unit set using the first set of RLC parameters, the network node is further caused to: select the first set of RLC parameters specified for the first retransmission policy for transmitting the one or more data units of the data unit set; and send, to the UE, a first activation indication to activate the first retransmission policy.

20. The network node according to claim 19, wherein the first activation indication is carried via a RLC control Protocol Data Unit (PDU), or other Layer-2 signalling messages.

21. The network node according to any one of claims 15 to 20, wherein, in response to the determination that the transmitted one or more data units of the data unit set meets thepredetermined threshold, the network node is further caused to send, to the UE, a second activation indication to activate the second retransmission policy.

22. The network node according to claim 21, wherein the second activation indication is carried via a RLC control Protocol Data Unit (PDU), or other Layer-2 signalling messages, and / or the second activation indication is used to inform the UE of discontinuation of expected RLC retransmissions.

23. The network node according to any one of claims 15 to 22, wherein the network node is further caused to: receive information related to an error correction configuration indicative of the one or more error correction characteristics from an application layer; and switch, based on the received information related to the error correction configuration and a current status of data unit reception, among at least the first retransmission policy and the second retransmission policy for transmitting further data units of the data unit set.

24. The network node according to claim 23, wherein the network node is further caused to receive information from the UE of a capability to support error correction, EC, -aware RLC policy switching based on the received information related to the error correction configuration.

25. The network node according to claim 24, wherein the capability to support EC-aware RLC policy switching comprises one of the following: the capability to support UE-autonomous EC-aware RLC policy switching based on at least a determination policy that the transmitted one or more data units of the data unit set meets the predetermined threshold, or the capability to support network-controlled EC-aware RLC policy switching based on an indication signalled by the network node.

26. The network node according to any one of claims 14 to 25, wherein the one or more error correction characteristics comprises forward error correction, FEC, information indicative of decodability of the data unit set specified by an application layer.

27. A system, comprising: a user equipment, UE, according to any one of claims 1 to 13, and a network node according to any one of claims 14 to 26, wherein the UE and the network node are configured to support an Automatic Repeat Request, ARQ, process when communicating with each other.

28. A method of a User Equipment, UE, that supports an Automatic Repeat Request, ARQ, process when communicating with a network node of a radio access network in accordance with configuration information including a plurality of Radio Link Control, RLC, parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate, the method comprising: receiving, from the network node, one or more data units of a data unit set using the first set of RLC parameters; and in response to a determination, based on one or more error correction characteristics indicative of a predetermined threshold to be metfor successfully decoding the data unit set, that the received one or more data units of the data unit set meets the predetermined threshold, receiving, from the network node, one or more remaining data units of the data unit set using the second set of RLC parameters.

29. A method of a network node that supports an Automatic Repeat Request, ARQ, process when communicating with a User Equipment, UE, the method comprising: configuring the UE with a configuration message for controlling a radio link between the network node and the UE, the configuration message comprising a plurality of Radio Link Control, RLC, parameters for controlling RLC retransmissions in the ARQ process, the plurality of RLC parameters comprising at least a first set of RLC parameters associated with a first retransmission rate, and a second set of RLC parameters associated with a second retransmission rate lower than the first retransmission rate; transmitting, to the UE, one or more data units of a data unit set using the first set of RLC parameters; determining, based on one or more error correction characteristics indicative of a predetermined threshold to be met for successfully decoding the data unit set, that thetransmitted one or more data units of the data unit set meets the predetermined threshold; and in response to the determination, transmitting, to the UE, one or more remaining data units of the data unit set using the second set of RLC parameters.

Images