SIDELINK RESOURCES TECHNICAL FIELD

The present invention relates generally to the field of wireless communications, and more particularly to sidelink resource utilization under intermittent coverage and control. To this end, the invention provides a network entity and a User Equipment (UE) for providing resources and/or resource configuration to one or more UEs for performing sidelink transmission. Moreover, the one or more UEs utilize the provided resources and/or resource configuration in case of an interruption of a communication over a link. This invention also presents the corresponding methods. BACKGROUND

Generally, the Fifth Generation (5G) New Radio (NR) supports the Sidelink (SL) resource allocation and control. For example, the 5G New Radio Vehicle-to-Everything (NR V2X) communications (starting from 3 GPP Release 16) the following are stated: o Complementing the Long Term Evolution (LTE) V2X (starting from Rel. 14 and 15).

o Supporting the advanced V2X use cases, including:

^■ Vehicles platooning

^■ Extended sensors

^■ Advanced driving

^■ Remote driving

o The Study Item (SI) is completed, and the Work Item (WI) has begun in the

3 GPP Rel. 16.

o It is feasible to support, for example:

^■ Unicast, groupcast, broadcast operation in sidelink (SL) via PC5 interface. ^■ Coexistence between SL and other cellular transmissions in a carrier.

^■ In-coverage, partial coverage, and out-of-coverage operation.

^■ Cross-RAT control.

Moreover, the NR V2X SL resource allocation are described. For instance, several new resource allocation modes for vehicle-to -vehicle (V2V) communications are introduced, as follows: o Mode 1: Base station (BS) schedules the SL resource(s) to be used by the user equipment (UE) for the SL transmission(s).

o Mode 2: a UE determines (i.e. BS does not schedule) the SL transmission resource(s) within the SL resources configured by the B S/network or pre configured SL resources. In addition, several modes are introduced based on the mode 2 as follow:

^■ Mode 2a: UE autonomously selects SL resource for transmission.

^■ Mode 2c: UE is configured with NR configured grant (Type-1 like) for SL transmission.

^■ Mode 2d: UE schedules SL transmissions of other UEs.

^■ Mode 2b: UE assists SL resource selection for other UE(s), a functionality which can be part of a), c), d).

Resource allocation Mode 1 and Mode 2 can be configured at the same time for the UE.

Lor NR V2X SL Mode 1 the following techniques are supported:

^■ Dynamic resource allocation

^■ Configured grant Type 1 and Type 2

Lor NR V2X SL Mode 2 the following techniques are supported:

^■ Sensing and resource (re-)selection procedures

^■ Reservation of SL resources at least for blind retransmission

Lor Mode 2a: sensing and resource selection in a semi-persistent manner.

Lor Mode 2c: single or multiple SL transmission patterns on each SL resource pool, (pre-)configured by gNB. Lor Mode 2d: gNB provides individual resource pool configurations and/or individual resource configurations to each group member UE (M-UE) through another UE (S-UE). Detailed Mode 2d agreement: in the context of group-based SL communication, it is supported for UE-A to inform its serving gNB about members UE-B, UE-C, and so on of a group, and for the gNB to provide individual resource pool configurations and/or individual resource configurations to each group member through UE-A. UE-A cannot modify the configurations, and there is no direct connection required between any member UE and the gNB. Higher-layer only signalling is used to provide the configurations. Such functionality is up to UE capability (ies).”

NR Uu control on NR SL:

o RRC

^■ Acquisition of V2X-specific SIB(s)

^■ Establishment of RRC connection

^■ Configuration of resource allocation modes

• Mode 1 and 2 can be configured at the same time for the UE

• Network can provide pools of resources in which UE selects autonomously SL grant for SL uni-/group-/broadcast, via broadcast system information and/or dedicated signaling.

• Mode 2 resource configuration can be provided for a given validity area.

^■ Mobility management

• During handover, the transmission and reception of V2X SL communication are performed based on at least configuration of the exceptional transmission resource pool and reception resource pool of the target cell.

• Cell reselection

^■ Reporting of UE SL information, SL-related measurement, information for traffic pattem(s).

o MAC

^■ Scheduling Request

^■ SL Buffer Status Reporting • LTE Uu control on NR SL

o LTE can provide semi-static configurations for NR SL Mode 1 and Mode

2.

o For Mode 1, the configuration is of a Type 1 configured grant:

^■ Configuration limited to time-frequency resources and periodicity.

^■ Without additional functions or procedures on the LTE Uu interface.

The interruption of vchiclc-to-cvcrything sidelink (V2X SL) may be, for example, the vehicle-to -vehicle (V2V) transmissions and receptions, due to intermittent or limited coverage and/or control on the SL resources utilized by the vehicular network entities. Some examples include:

o Interruption of radio resource control (RRC) connection between the vehicular user equipment (UE) and the base station (BS) in cellular network-controlled V2V communications, including

^■ radio link failure,

^■ handover failure,

^■ cell (re-)selection failure,

^■ under any SL mode of operation in terms of radio resource allocation. o Interruption of RRC connection between two or more vehicular UEs on V2V communications where a UE is involved in the control of resources for SL communications .

o Intermittent and limited coverage or control conditions among the vehicular network entities exist during early stages of the V2X network deployment, and also arise due to obstacles (e.g., a road tunnel, or wireless channel conditions limiting the connectivity) in any stage of network deployment, especially due to highly dynamic vehicular environment.

o Interruptions in V2V transmissions lead to degradation of communication performance, such as in terms of reliability and latency, which eventually negatively impacts the V2X use cases targeting safety and efficiency on the roads.

The V2V communications including the control of communication resources (e.g., resource configuration or allocation) among the network entities is supported by the 3 GPP standard LTE -A Releases 14 and 15, as well as the upcoming standard NR (New Radio) Release 16. Moreover, in terms of resource allocation for V2V communications, two modes of operation are defined in general. Using the Rel. 16 terminology, the two modes are called: Mode 1 where the resources are allocated by the network, i.e., BS, and Mode 2, where the UEs allocates the resources themselves autonomously. Accordingly, Mode 2 is suitable for V2V communications without any network coverage.

Furthermore, during the study phase of NR V2X by 3GPP, several sub-modes for Mode 2 were introduced. Among them, Mode 2d is defined to be the mode where the BS provides the resources to a group of UEs, through another UE.

In addition, interruption of the RRC connection on the Uu link (between UE and BS) are handled by the UEs operating Mode 1 or 2 as follows, according to the standard specifications:

o Mode 1 UEs leave any resources they are assigned, switch to a set of resources called“SL exceptional resources pool”, and randomly select resources, until eventually switching to Mode 2 operation

o Mode 2 UEs leave any resources they are assigned, and switch to pre configured set of resources for out-of-coverage, or use the resource pools valid for an area.

However, the specified conventional method have the disadvantage that the different availability of resources for different modes as well as the random selection of resources could easily and negatively impact the SL communications, e.g., in terms of reliability and latency.

Moreover, the interruption of the RRC connection on the PC5 link (between UEs) under Mode 2d is not yet addressed in the standard specifications. The potential disadvantages are:

o both Uu and PC5 RRC connections could be interrupted

o behavior of the UEs upon interruption is not defined

o no fallback mode for Mode 2d is defined

All of these disadvantages would lead to a problem worse than that of Mode 1 or Mode 2 operation.

SUMMARY

In view of the above-mentioned problems and disadvantages, embodiments of the present invention aim to improve the conventional devices and methods. An objective is to provide a network entity and a UE that are less sensitive to interruptions of a communication link, in particular regarding sidelink transmissions. In particular, the network entity and UE should support utilization of resources and/or resource configuration for sidelink transmission even in case of an interruption of a communication over one or more links.

The objective of the present invention is achieved by the embodiments provided in the enclosed independent claims. Advantageous implementations of the embodiments are further defined in the dependent claims.

In particular, embodiments of the invention propose a network entity and one or more UEs that are able to continue transmitting/receiving on the SL, irrespective of any interruption of coverage and/or interruption of control in terms of radio resources, either by using their already existing SL communication resource and/or resource configuration, or by using a new SL communication resource and/or resource configuration, at least until a first threshold condition is met (e.g., a timer, a distance, a probability, etc.), for example, irrespective of the resource-allocation mode(s) they operate (e.g., Mode 1, Mode 2, Mode 2d, simultaneous modes, mode switching periods, etc.).

The main advantages of the embodiments of the invention can be summarized as follows:

• The SL transmissions and receptions will not be interrupted due to interruptions or changes in coverage and/or resource control.

• The uninterrupted SL transmissions/receptions would ensure stability of the QoS performance for the (advanced) V2X use cases.

A first aspect of the invention provides a network entity configured to determine a first threshold indicating the end of utilization, by one or more User Equipments, UEs, of one or more sidelink resources and/or sidelink resource configuration, for performing sidelink transmission; and send the first threshold and the one or more sidelink resources and/or the sidelink resource configuration to the one or more UEs.

The network entity may be, for example, a BS, eNB (Evolved Node B), gNB (Next Generation Node B), RSU (Road Side Unit), UE, etc. In particular, the network entity (hereinafter also referred to as the BS) may determine the first threshold and provide it along with the resources and/or resource configuration.

The resources /configurations may be, e.g., pool, TFRP, etc., and may further be associated with an interruption, etc.

In some embodiments, the first threshold and the one or more sidelink resources and/or the sidelink resource configuration may be provided for an interruption of a communication over a link, such as intermittent coverage and control under PC5 and/or Uu RRC connection interruption.

The first threshold may indicate the end of utilization. The end of utilization may be a time information, a distance information, a location information, etc.

In an implementation form of the first aspect, the network entity is further configured to determine a second threshold indicating the start of utilization, by the one or more UEs, of the one or more sidelink resources and/or the sidelink resource configuration for performing sidelink transmission; and send the second threshold to the one or more UEs.

The second threshold may indicate the start of utilization. The start of utilization may be a time information, a distance information, a location information, etc. In some embodiments, the second threshold may be determined for an expected interruption of a communication over a link e.g., OOC.

In a further implementation form of the first aspect, the second threshold is indicative of an expected link interruption.

In a further implementation form of the first aspect, the network entity is further configured to determine the first threshold and/or the second threshold based on one or more of: a time information indicating a start and/or an end of a link interruption, a distance information indicating a start and/or an end of a link interruption, a predefined location information of a link interruption,

a duration of a link interruption,

a frequency of a link interruption,

a probability value of a link interruption,

a predefined area,

received information from the one or more UEs and/or another network entity.

In a further implementation form of the first aspect, a link interruption includes one or more of:

an interruption of a communication over a link between the network entity and a determined UE connected over at least one link to one or more UEs;

an interruption of a communication over at least one link between the network entity and the one or more UEs;

an interruption of a communication over the at least one link between the determined UE and the one or more UEs.

In particular, the determined UE may be, for example, a scheduling UE (S-UE). The one or more UEs may be member UEs (M-UEs).

In a further implementation form of the first aspect, the one or more sidelink resources and/or the sidelink resource configuration comprises at least one of:

a configured grant,

a dynamic grant,

a time- frequency repetition pattern,

a resource pool,

a semi-persistent schedule,

a one-shot schedule.

A second aspect of the invention provides a UE configured to determine one or more sidelink resources and/or sidelink resource configuration for one or more UEs for performing sidelink transmission; and send, the one or more sidelink resources and/or the sidelink resource configuration to the one or more UEs, to be used in case of a link interruption.

The UE may be an S-UE. In some embodiments, the S-UE may be at the same time an M- UE.

In some embodiments, the UE (e.g., the S-UE) may obtain the one or more sidelink resources and/or the sidelink resource configuration from the network entity, and may further forward them to the one or more UEs.

In some embodiments, a determined UE (e.g., an M-UE) may obtain the one or more sidelink resources and/or the sidelink resource configuration from another UE (e.g., an S- UE), and may further forward them to the one or more UEs.

In some embodiments, the one or more sidelink resources and/or the sidelink resource configuration may be provided for an interruption of a communication, under the PC5 and/or Uu the RRC connection interruption.

In an implementation form of the second aspect, a link interruption includes one or more of:

an interruption of a communication over a link between the network entity and a determined UE connected over at least one link to one or more UEs; an interruption of a communication over at least one link between the network entity and the one or more UEs;

an interruption of a communication over the at least one link between the determined UE and the one or more UEs.

In a further implementation form of the second aspect, the UE is further configured to determine a first threshold indicating the end of utilization, by the one or more UEs, of the one or more sidelink resources and/or a sidelink resource configuration for sidelink transmission; and send the first threshold to the one or more UEs and/or the network entity.

The first threshold may indicate the end of utilization. The end of utilization may be a time information, a distance information, a location information, etc. In some embodiments, the first threshold that is determined by the UE (e.g., S-UE) may be different from the first threshold that is determined by the network entity.

In a further implementation form of the second aspect, the UE is further configured to determine a second threshold indicating the start of utilization, by the one or more UEs, of the one or more sidelink resources and/or the sidelink resource configuration for performing sidelink transmission; and send the second threshold to the one or more UEs and/or the network entity.

The second threshold may indicate the start of utilization. The start of utilization may be a time information, a distance information, a location information, etc.

In some embodiments, the second threshold that is determined by the UE (e.g., S-UE) may be different from the second threshold that is determined by the network entity.

In a further implementation form of the second aspect, the second threshold is indicative of a link interruption that is expected.

In a further implementation form of the second aspect, the UE is further configured to determine the first threshold and/or the second threshold based on one or more of:

a time information indicating a start and/or an end of a link interruption, a distance information indicating a start and/or an end of a link interruption, a predefined location information of a link interruption,

a duration of a link interruption,

a frequency of a link interruption,

a probability value of a link interruption,

a predefined area,

received information from the one or more UEs and/or another network entity.

In a further implementation form of the second aspect, the UE is further configured to indicate to the one or more UEs, a link interruption. In a further implementation form of the second aspect, the one or more sidelink resources and/or the sidelink resource configuration comprises at least one of:

a configured grant,

a dynamic grant,

a time- frequency repetition pattern,

a resource pool,

a semi-persistent schedule,

a one-shot schedule.

In a further implementation form of the second aspect, the UE is further configured to obtain from the network entity and/or another UE (e.g., an S-UE), one or more of:

the one or more sidelink resources and/or the sidelink resource configuration,

- the first threshold,

- the second threshold.

A third aspect of the invention provides a UE configured to obtain a first threshold and/or a second threshold and one or more sidelink resources and/or sidelink resource configuration, for performing sidelink transmission; and utilize, in case of a link interruption, the one or more sidelink resources and/or the sidelink resource configuration for sidelink transmission, from determining a link interruption or from the start of utilization as indicated by the second threshold, until the end of utilization as indicated by the first threshold.

In particular, the UEs may utilize the one or more sidelink resources and/or the sidelink resource configuration in case of an interruption of a communication over a link. The UE may be a M-UE (or M-UE and S-UE at the same time).

In an implementation form of the third aspect, the UE is further configured to determine the interruption of at least one link which is between the UE and another UE, determine the interruption of a link which is between the UE and a network entity, and/or determine the interruption of a link which is between the other UE and a network entity, based on an indication received from the other UE. A fourth aspect of the invention provides a method for network entity, the method comprising determining a first threshold indicating the end of utilization, by one or more User Equipments, UEs, of one or more sidelink resources and/or sidelink resource configuration, for performing sidelink transmission; and sending the first threshold and the one or more sidelink resources and/or the sidelink resource configuration to the one or more UEs.

In an implementation form of the fourth aspect, the method further comprises determining a second threshold indicating the start of utilization, by the one or more UEs, of the one or more sidelink resources and/or the sidelink resource configuration for performing sidelink transmission; and sending the second threshold to the one or more UEs.

In a further implementation form of the fourth aspect, the second threshold is indicative of an expected link interruption.

In a further implementation form of the fourth aspect, the method further comprises determining the first threshold and/or the second threshold based on one or more of:

a time information indicating a start and/or an end of a link interruption, a distance information indicating a start and/or an end of a link interruption, a predefined location information of a link interruption,

a duration of a link interruption,

a frequency of a link interruption,

a probability value of a link interruption,

a predefined area,

received information from the one or more UEs and/or another network entity.

In a further implementation form of the fourth aspect, a link interruption includes one or more of:

an interruption of a communication over a link between the network entity and a determined UE connected over at least one link to one or more UEs; an interruption of a communication over at least one link between the network entity and the one or more UEs;

an interruption of a communication over the at least one link between the determined UE and the one or more UEs. In a further implementation form of the fourth aspect, the one or more sidelink resources and/or the sidelink resource configuration comprises at least one of:

a configured grant,

a dynamic grant,

a time- frequency repetition pattern,

a resource pool,

a semi-persistent schedule,

a one-shot schedule.

A fifth aspect of the invention provides a method for UE, the method comprising determining one or more sidelink resources and/or sidelink resource configuration for one or more UEs for performing sidelink transmission; and sending, the one or more sidelink resources and/or the sidelink resource configuration to the one or more UEs, to be used in case of a link interruption.

In an implementation form of the fifth aspect, a link interruption includes one or more of:

an interruption of a communication over a link between the network entity and a determined UE connected over at least one link to one or more UEs; an interruption of a communication over at least one link between the network entity and the one or more UEs;

an interruption of a communication over the at least one link between the determined UE and the one or more UEs;

In a further implementation form of the fifth aspect, the method further comprises determining a first threshold indicating the end of utilization, by the one or more UEs, of the one or more sidelink resources and/or a sidelink resource configuration for sidelink transmission; and sending the first threshold to the one or more UEs and/or the network entity.

In a further implementation form of the fifth aspect, the method further comprises determining a second threshold indicating the start of utilization, by the one or more UEs, of the one or more sidelink resources and/or the sidelink resource configuration for performing sidelink transmission; and sending the second threshold to the one or more UEs and/or the network entity.

In a further implementation form of the fifth aspect, the second threshold is indicative of a link interruption that is expected.

In a further implementation form of the fifth aspect, the method further comprises determining the first threshold and/or the second threshold based on one or more of

a time information indicating a start and/or an end of a link interruption, a distance information indicating a start and/or an end of a link interruption, a predefined location information of a link interruption,

a duration of a link interruption,

a frequency of a link interruption,

a probability value of a link interruption,

a predefined area,

received information from the one or more UEs and/or another network entity.

In a further implementation form of the fifth aspect, the method further comprises indicating to the one or more UEs, a link interruption.

In a further implementation form of the fifth aspect, the one or more sidelink resources and/or the sidelink resource configuration comprises at least one of:

a configured grant,

a dynamic grant,

a time- frequency repetition pattern,

a resource pool,

a semi-persistent schedule,

a one-shot schedule.

In a further implementation form of the fifth aspect, the method further comprises obtaining from the network entity and/or another UE (e.g., an S-UE), one or more of:

the one or more sidelink resources and/or the sidelink resource configuration,

- the first threshold,

- the second threshold. A sixth aspect of the invention provides a method for UE, the method comprising obtaining a first threshold and/or a second threshold and one or more sidelink resources and/or sidelink resource configuration, for performing sidelink transmission; and utilizing, in case of an interruption, the one or more sidelink resources and/or the sidelink resource configuration for sidelink transmission, from determining a link interruption or from the start of utilization as indicated by the second threshold, until the end of utilization as indicated by the first threshold.

In an implementation form of the sixth aspect, the method further comprises determining the interruption of at least one link which is between the UE and another UE, determining the interruption of a link which is between the UE and a network entity, and/or determine the interruption of a link which is between the other UE and a network entity, based on an indication received from the other UE.

It has to be noted that all devices, elements, units and means described in the present application could be implemented in the software or hardware elements or any kind of combination thereof. All steps which are performed by the various entities described in the present application as well as the functionalities described to be performed by the various entities are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. Even if, in the following description of specific embodiments, a specific functionality or step to be performed by external entities is not reflected in the description of a specific detailed element of that entity which performs that specific step or functionality, it should be clear for a skilled person that these methods and functionalities can be implemented in respective software or hardware elements, or any kind of combination thereof.

BRIEF DESCRIPTION OF DRAWINGS

The above described aspects and implementation forms of the present invention will be explained in the following description of specific embodiments in relation to the enclosed drawings, in which FIG. 1 is a schematic view of a network entity, according to an embodiment of the present invention.

FIG. 2 is a schematic view of a UE, according to an embodiment of the present invention.

FIG. 3 is a schematic view of another UE, according to an embodiment of the present invention.

FIG. 4 is a schematic view of performing a sidelink transmission in case of an interruption of a communication over a link between the network entity and the S-UE, according to an embodiment of the present invention.

FIG. 5 is a schematic view of performing a sidelink transmission in case of an expected interruption of a communication over a link between the network entity and the S-UE, according to an embodiment of the present invention.

FIG. 6 is a schematic view of performing a sidelink transmission in case of an interruption of a communication over a link between the S-UE and the M-UE, according to an embodiment of the present invention.

FIG. 7 is a schematic view of performing a sidelink transmission in case of an expected interruption of a communication over a link between the S-UE and the M-UE, according to an embodiment of the present invention. FIG. 8 is a schematic view of a configured grant by the network entity.

FIG. 9 is a flowchart of a method for a network entity, according to an embodiment of the invention. FIG. 10 is a flowchart of a method for a UE, according to an embodiment of the invention.

FIG. 11 is a flowchart of a method for a UE, according to an embodiment of the invention. DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 is a schematic view of a network entity 100, according to an embodiment of the present invention.

The network entity 100 (e.g., a BS, or gNB) is configured to determine a first threshold 101 indicating the end of utilization Tl, by one or more User Equipments, UEs 110, 120, 130, of one or more sidelink resources 102 and/or sidelink resource configuration 103, for performing sidelink transmission.

The network entity 100 is configured to send the first threshold 101 and the one or more sidelink resources 102 and/or the sidelink resource configuration 103 to the one or more UEs 110, 120, 130. The network entity 100 may comprise a circuitry (not shown in FIG. 1) which may comprise hardware and software. The hardware may comprise analog or digital circuitry, or both analog and digital circuitry. In some embodiments, the circuitry comprises one or more processors and a non-volatile memory connected to the one or more processors. The non-volatile memory may carry executable program code which, when executed by the one or more processors, causes the device to perform the operations or methods described herein.

FIG. 2 is a schematic view of a UE, according to an embodiment of the present invention. The UE 110 (it may be S-UE, or S-UE and M-UE at the same time) is configured to determine one or more sidelink resources 102 and/or sidelink resource configuration 103 for one or more UEs 120, 130 for performing sidelink transmission.

The UE 110 is configured to send, in case of a link interruption, the one or more sidelink resources 102 and/or the sidelink resource configuration 103 to the one or more UEs 120, 130.

The UE 110 may comprise a circuitry (not shown in FIG. 2) which may comprise hardware and software. The hardware may comprise analog or digital circuitry, or both analog and digital circuitry. In some embodiments, the circuitry comprises one or more processors and a non-volatile memory connected to the one or more processors. The non-volatile memory may carry executable program code which, when executed by the one or more processors, causes the device to perform the operations or methods described herein.

FIG. 3 is a schematic view of another UE, according to an embodiment of the present invention.

The UE 120 (it may be M-UE, or S-UE and M-UE at the same time) is configured to obtain a first threshold 101 and/or a second threshold 301 and one or more sidelink resources 102 and/or sidelink resource configuration 103, for performing sidelink transmission.

The UE 120 is configured to utilize, in case of a link interruption, the one or more sidelink resources 102 and/or the sidelink resource configuration 103 for sidelink transmission, from determining a link interruption or from the start of utilization TO as indicated by the second threshold 301, until the end of utilization T 1 as indicated by the first thresho Id 101.

The UE 120 may comprise a circuitry (not shown in FIG. 3) which may comprise hardware and software. The hardware may comprise analog or digital circuitry, or both analog and digital circuitry. In some embodiments, the circuitry comprises one or more processors and a non-volatile memory connected to the one or more processors. The non-volatile memory may carry executable program code which, when executed by the one or more processors, causes the device to perform the operations or methods described herein.

In the following, several exemplarily embodiments are presented for performing a sidelink transmission in case of interruption that could potentially occur in the network system, without limiting the present disclosure to these specific conditions.

In FIG. 4 and FIG. 5, the interruptions of the link between UE 110 and the BS 100 are discussed. Moreover, in FIG. 6 and FIG. 7, the interruptions on the direct link between the UEs 110, 120, 130 are discussed.

Additionally, FIG. 4 and FIG. 6 present exemplarily embodiments, in which the interruption is not expected beforehand (i.e., unexpected interruption). Also, FIG. 5 and FIG. 7 illustrates embodiments, in which the interruption is expected beforehand (expected interruption), which may be expected beforehand by any one of the network entity 100 and/or the S-UE 110 and/or the M-UEs 120, 130.

To illustrate, such diverse conditions may especially arise under a mode where the network entity 100 is providing the one or more sidelink resources 102 and/or sidelink resource configuration 103 to a group of UEs (e.g., the M-UEs 120, 130), which engage in the SL communications. The one or more sidelink resources 102 and/or sidelink resource configuration 103 may be provided to them (e.g., to the M-UEs 120, 130) via another UE (called the S-UE 110) that is configured to forward it from the BS 100.

Reference is made to FIG. 4, which is a schematic view of performing a sidelink transmission in case of an interruption of a communication over a link between the network entity 100 and the S-UE 110, according to an embodiment of the present invention.

Interruption of the link (e.g., Uu RRC) may occur between the network entity 100 (i.e., the BS 100) and the S-UE 110 (i.e., the UE that is configured to forward the one or more sidelink resources 102 and/or sidelink resource configuration 103 to the M-UEs 120, 130 (another set of UEs)).

The precondition may be, for example, that the one or more sidelink resources 102 and/or sidelink resource configuration 103 of the M-UE(s) 120, 130 are provided to the S-UE 110 and/or the M-UE(s) 120, 130 by the BS 100. For example, the one or more sidelink resources 102 and/or sidelink resource configuration 103 may be provided when the S-UE 110 and/or the M-UE(s) 120, 130 are/were in the coverage of the BS 100.

The possible solution may be, for example, in the cases of the S-UE 110 having a connection interruption to the BS 100, (e.g., on the Uu RRC connection) or going (temporarily) out of coverage (OOC), since the S-UE already received the one or more sidelink resources 102 and/or sidelink resource configuration 103, from the BS 100, the S- UE 110 should still be able to inform the M-UEs 120, 130 of the one or more sidelink resources 102 and/or sidelink resource configuration 103. Moreover, the M-UE(s) 120, 130 should still be able to utilize the one or more sidelink resources 102 and/or sidelink resource configuration 103, at least until the end of utilization as indicated by the first threshold 101. The end of utilization (Tl) may be, for example, time, distance, location information, etc.

Moreover, the end of utilization Tl may be determined (e.g., configured and further sent/forwarded) by the BS 100 (gNB) to the S-UE 110 and/or the M-UEs 120, 130. The end of utilization Tl may also be determined (configured and further sent/forwarded) by any UE, or may be pre-configured.

Reference is made to FIG. 5, which is a schematic view of performing a sidelink transmission in case of an expected interruption of a communication over a link between the network entity 100 and the S-UE 110, according to an embodiment of the present invention.

For example, the expected interruption may be the interruption of the link (e.g., Uu RRC) between the BS 110 and the S-UE 110, i.e., the UE that is configured to forward the one or more sidelink resources 102 and/or sidelink resource configuration 103 to the M-UEs 120, 130 (another set of UEs). Moreover, one or more of the network entities and/or the UEs (e.g., BS 100 and/or the S-UE 110 and/or the M-UE 120, 130) may be aware of the interruption or the OOC condition beforehand. The interruption may be expected, i.e. it may be known in advanced that the interruption may occur, etc.

The precondition may be, for example, the one or more sidelink resources 102 and/or sidelink resource configuration 103 of the M-UEs 120, 130 are provided to the S-UE 110 by the BS 100.

For example, the one or more sidelink resources 102 and/or sidelink resource configuration 103 may be provided when the S-UE 110 and/or the M-UE(s) 120, 130 were in the coverage of the BS 100.

The possible solution may be, for example, that the BS 100 also provides the one or more sidelink resources 102 and/or sidelink resource configuration 103 (which may be the same or different from those used when the interruption is not known beforehand, i.e., unexpected interruption) to be utilized upon the S-UE 110 encountering the expected interruption (e.g., the OOC). The possible solution may be, for example, in the cases of the S-UE 110 having expected an interruption (e.g., the OOC), which may be for example, on the Uu RRC connection, that the S-UE 110 may still be able to inform the M-UEs 120, 130 by sending the one or more sidelink resources 102 and/or sidelink resource configuration 103. Moreover, the M- UEs 120, 130 may be able to utilize the one or more sidelink resources 102 and/or sidelink resource configuration 103 at least until the end of utilization (Tl, which may be a distance information, a time information, a location information, etc.) as indicated by the first threshold 101.

In addition, the second threshold 301 may be determined, which indicates the start of the utilization TO (which may be the start time, a location information for starting the utilization, a distance information, etc.). The utilization starts with the TO (indicated by the second threshold 301), instead of the condition of“upon encountering the OOC”, and continues until the end of utilization Tl as indicated by the first threshold 101.

Furthermore, both first threshold 101 and second threshold (and/or the TO and/or the Tl) may be determined (and further sent/forwarded) by the BS 100 (e.g., gNB) to the S-UE 110 and/or the M-UEs 120, 130. The first threshold 101 and/or the second threshold 301 may also be determined (configured and further sent/forwarded) by any UE, or may be pre configured.

Reference is made to FIG. 6, which is a schematic view of performing a sidelink transmission in case of an interruption of a communication over a link between the S-UE 110 and the M-UE 120, 130, according to an embodiment of the present invention.

The interruption of the link (e.g., PC5 RRC) may occur between the S-UE 110 (i.e., the UE that is configured to forward the one or more sidelink resources 102 and/or sidelink resource configuration 103 to the M-UEs 120, 130 (another set of UEs)) and one or more of M-UEs.

The precondition may be, for example, that the one or more sidelink resources 102 and/or sidelink resource configuration 103 of the M-UE(s) 120, 130 are provided by the BS 100 (gNB) and/or the S-UE 110, when S-UE 110 and the M-UEs 120, 130 are connected. The possible solution may be, for example, in the cases of M-UE 120, 130 having interruptions of coverage of S-UE 110, (e.g., on the PC5 RRC connection), that the M-UE 120, 130 should still be able to utilize the one or more sidelink resources 102 and/or side link resource configuration 103 at least until the end of utilization (e.g., a time) T1 as indicated by the first threshold 101.

For example, if the M-UE still has V2V traffic to transmit, it will continue utilizing the resources it was assigned in coverage, during the intermittent coverage.

Moreover, the end of utilization T1 may be determined (e.g., configured and further sent/forwarded) by the BS 100 (gNB) to the S-UE 110 and/or the M-UEs 120, 130. The end of utilization T1 may also be determined (configured and further sent/forwarded) by any UE, or may be pre-configured.

Reference is made to FIG. 7, which is a schematic view of performing a sidelink transmission in case of an expected interruption of a communication over a link between the S-UE and the M-UE, according to an embodiment of the present invention.

For example, the expected interruption may be the interruption of the link (e.g., PC5 RRC) between the UE that is configured to forward one or more sidelink resources 102 and/or sidelink resource configuration 103 (S-UE 110) to another set of UEs (M-UEs 120, 130), and one of these UEs (M-UE 120, 130), where the S-UE 110 and/or the BS 100 are aware of the interruption or the OOC condition beforehand.

The precondition may be, for example, that the one or more sidelink resources 102 and/or sidelink resource configuration 103 of the M-UEs 120, 130 are provided (e.g., configured and/or forwarded) by the S-UE 110, when S-UE 110 and M-UEs 120, 130 are connected.

The possible solution may be, for example, that the BS 100 and/or S-UE 110 also provide the one or more sidelink resources 102 and/or sidelink resource configuration 103 to be utilized upon M-UEs 120, 130 encountering the interruption/OOC of the link to the S-UE 110. Moreover, in the cases of M-UE 120, 130 having interruptions/OOC, (e.g., on the PC5 RRC connection), the M-UEs 120, 130 may be able to utilize the one or more side link resources 102 and/or sidelink resource configuration 103 at least until the end of utilization (Tl, which may be a distance information, a time information, a location information, etc.) as indicated by the first threshold 101.

In addition, the second threshold 301 may be determined, which indicates the start of the utilization TO (which may be the start time, a location information for starting the utilization, a distance information, etc.). The utilization starts with the TO (indicated by the second threshold 301), instead of the condition of“upon encountering the OOC”, and continues until the end of utilization Tl as indicated by the first threshold 101.

Furthermore, both first threshold 101 and second threshold (and/or the TO and/or the Tl) may be determined (and further sent/forwarded) by the BS 100 (e.g., gNB) to the S-UE 110 and/or the M-UEs 120, 130. The first threshold 101 and/or the second threshold 301 may also be determined (configured and further sent/forwarded) by any UE, or may be pre configured.

Reference is made to FIG. 8, which is a schematic view of a configured grant (e.g., the configured grant is based on a semi-persistent scheduling configuration) by the network entity 100.

The scheme 800 and implementation illustrated in FIG. 8 is exemplarily illustrated for the embodiment of FIG. 5 in which an expected interruption of a communication over a link between the network entity 100 and the S-UE 100.

The precondition is that an interruption on the link between the BS 100 and S-UE 110 happens, where the BS 100 is aware of the interruption beforehand. Moreover, the BS 100 configures and provides the first threshold 101 and the second threshold 301 (e.g., the end of utilization Tl and the start of utilization TO as timers), and indicates them (for example at 801 in scheme 800 of FIG.8) in the SL type-1 configured grant configuration which is provided to S-UE 110 in coverage to be forwarded to one of the M-UEs 120, 130. Accordingly, the M-UE 120, 130 utilizes this configured grant during the period between TO and T1 corresponding to the interruption time of the link.

Moreover, the first threshold 101 and the second threshold 301 may be provided within the 3GPP NRUu ConfiguredGrantConfig information element, indicated at 801 in scheme 800 of FIG. 8. Note that the NR SL configured grants would have a similar set of parameters, however the final version of related specification is not yet available in the standard in Release 16.

FIG. 9 shows a method 900 according to an embodiment of the invention for network entity 100. The method 900 may be carried out by the network entity 100, as it described above.

The method 900 comprises a step 901 of determining a first threshold 101 indicating the end of utilization Tl, by one or more User Equipments, UEs 110, 120, 130, of one or more sidelink resources 102 and/or sidelink resource configuration 103, for performing sidelink transmission.

The method 900 further comprises a step 902 of sending the first threshold 101 and the one or more sidelink resources 102 and/or the sidelink resource configuration 103 to the one or more UEs 110, 120, 130.

FIG. 10 shows a method 1000 according to an embodiment of the invention for UE 110. The method 1000 may be carried out by the UE 110 (and/or UE 120 and/or UE 130), as it described above.

The method 1000 comprises a step 1001 of determining one or more sidelink resources 102 and/or sidelink resource configuration 103 for one or more UEs 120, 130 for performing sidelink transmission.

The method 1000 further comprises a step 1002 of sending, the one or more sidelink resources 102 and/or the sidelink resource configuration 103 to the one or more UEs 120, 130, to be used in case of a link interruption. FIG. 11 shows a method 1100 according to an embodiment of the invention for UE 120. The method 1100 may be carried out by the UE 120 (and/or UE 110 and/or UE 130), as it described above. The method 1100 comprises a step 1101 of obtaining a first threshold 101 and/or a second threshold 301 and one or more sidelink resources 102 and/or sidelink resource configuration 103, for performing sidelink transmission.

The method 1100 further comprises a step 1102 of utilizing, in case of a link interruption, the one or more sidelink resources 102 and/or the sidelink resource configuration 103 for sidelink transmission, from determining a link interruption or from the start of utilization TO as indicated by the second threshold 301, until the end of utilization T1 as indicated by the first threshold 101. The present invention has been described in conjunction with various embodiments as examples as well as implementations. However, other variations can be understood and effected by those persons skilled in the art and practicing the claimed invention, from the studies of the drawings, this disclosure and the independent claims. In the claims as well as in the description the word“comprising” does not exclude other elements or steps and the indefinite article“a” or“an” does not exclude a plurality. A single element or other unit may fulfill the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in the mutual different dependent claims does not indicate that a combination of these measures cannot be used in an advantageous implementation.

List of acronyms and glossaries:

3GPP 3rd Generation Partnership Project

5G 5th Generation

BS Base Station

eNB Evolved Node B

gNB Next Generation Node B

LTE Long-Term Evolution

LTE-A LTE Advanced

M-UE Member UE

RRC Radio Resource Control S-UE Scheduling UE

NR New Radio

QoS Quality of Service

SI Study Item

- SIB System Information Block

SL Sidelink

UE User Equipment

V2V V ehicle-to -V ehicle V2X V ehicle-to -Everything - WI Work Item