WO2025032087A1 - Method for beam failure indication for sidelink - Google Patents

Abstract

This application describes a method for Beam Failure indication for Sidelink, whereby Sidelink BFI is triggered based on PSFCH carrying sidelink HARQ feedback and BFI is declared at transmitter side, Unicast communication is established, and feedback, which is HARQ with ACK or NACK is expected at transmitted side, characterized by, that a timer (_TBFI) is established and used to verify the ratio between NACKs and ACKs as criteria for BFI.

Description

TITLE

Method for Beam Failure indication for Sidelink

TECHNNICAL FIELD

The present disclosure relates to wireless communications, and more particularly to techniques and apparatuses for vehicle-to-everything (V2X) sidelink beam failure indication.

BACKGROUND

Long Term Evolution (LTE) vehicle-to-everything (V2X) Transmission Mode: Rel-14 introduces two new V2X communication modes (modes 3 and 4) specifically designed for Vehicle-to-Vehicle Communication (V2V) communications. In mode 3, the cellular network selects and manages the radio resources used by vehicles for their direct V2V communications. In mode 4, V2X user equipment (UE) autonomously select the radio resources for their direct V2V communications. LTE V2X mode 4 can operate without cellular coverage and is therefore considered the baseline V2V mode since safety applications cannot depend on the availability of cellular coverage. Mode 4 includes a distributed scheduling scheme for vehicles to select their radio resources and includes the support for distributed congestion control. In LTE V2X, only broadcast V2X communication is supported.

Wireless communications systems may include or provide support for various types of communications systems, such as vehicle related communications systems (e.g., vehicle-to-everything (V2X) communications systems). Vehicle related communications systems may be used by vehicles to increase safety and to help prevent collisions of vehicles. Information regarding inclement weather, nearby accidents, road conditions, and/or other information may be conveyed to a driver via the vehicle related communications system. In some cases, sidelink user equipments (UEs), such as vehicles, may communicate directly with each other using device-to- device (D2D) communications over a D2D wireless link. These communications can be referred to as sidelink communications.

New Radio (NR) V2X Transmission Mode: Like LTE V2X transmission mode 3 and 4, NR supports two modes, i.e. , mode 1 and mode 2 for V2X transmission in Rel-16. InNR V2X, sidelink resource allocation mode 1 and mode 2 are supported. In mode 1 , the network (e.g. gNB) schedules the sidelink resources used by the V2X UE for sidelink transmission. In mode 2, V2X UE determines the sidelink resources used for sidelink transmission within the sidelink resources configured by the base station or preconfigured sidelink resources. Mode 1 supports the network (e.g. gNB) to assign the sidelink resources for both dedicated sidelink carrier and shared licensed carrier between Uu and sidelink through the Uu interface. The resources used for sidelink transmission may be dynamically allocated, or pre-configured by the Radio Resource Control (RRC) or based on activation and deactivation. Section 9 Sidelink, 3GPP TS 36.211 V15.5.0 and Section 14 UE procedures related to Sidelink, 3GPP TS 36.213 V15.5.0 are incorporated by reference in their entirety.

As the demands for sidelink communications increase, different V2X communications systems compete for the same wireless communications resources. Moreover, some sidelink UEs may be power limited. Accordingly, there is a need to improve the efficiency of sidelink wireless communications.

US 2022/0399927 A1 describes methods, systems, and devices which are used to implement BFR, SL-RS for BFD, radio link monitoring, or frequency assisted beam failure recovery, among other things. Link Recovery and sidelink beamforming, is described. /V NACKs and No-response are used to determine the BFI criteria. There is no information to signaling mechanisms for adaptation.

US 2022/0006505 A1 describes a method of wireless communication. This method of wireless communication by a first sidelink UE measures multiple reference signals periodically transmitted by a second sidelink UE using multiple receive beams corresponding to reference signals in response to a beam failure declared by the first UE. The method also selects one of the reference signals that satisfies a condition. The method further includes notifying the second sidelink UE of the selected reference signal using a beam corresponding to the selected reference signal. Another method of wireless communications by a first sidelink UE includes periodically transmitting, to a second sidelink UE, multiple beam failure recovery (BFR) reference signals across multiple transmit beams. The method also includes receiving, from the second sidelink UE, an indication of a selected beam for communications between the first sidelink UE and the second sidelink UE. The method notifies the second sidelink UE of successful beam failure recovery. This application descrinbes that, if the receive signal strength of the BFD reference signals falls below the threshold a certain number, N, times before the BFD timer expires, UE2 declares beam failure (BF) and triggers beam failure recovery.

Well known is the support of sidelink beam management. Reusing existing sidelink CSI framework and reusing Uu beam management concepts wherever possible are also defined. SL beam management, based on the definition provided for NR Uu in 3GPP TR 38.802, is to “acquire and maintain a set of [UE] beams that can be used for [SL] transmission/reception”. General procedures are procedures for initial beam pairing, and procedures for initial beam pairing and sidelink beam failure indication. Furthermore the information related to a sidelink beam failure instance that the PHY layer provides to the MAC layer are investigated.

This application solves the problem of how triggering sidelink BFI can be done. Thos prpblem is solved by introducing a timer to verify the ratio between NACKs and ACKs as criterion for BFI.

The probmel is solved by the embodiments describe.

One preferred embodiment of the method for Beam Failure indication for Sidelink, whereby parameters for Sidelink BFI is triggered based on PSFCH carrying sidelink HARQ feedback and BFI is declared at transmitter side, Unicast communication is established, and feedback, which is HARQ with ACK or NACK is expected at transmitted side, is characterized by, that a timer (7 BFI) is established and used to verify the ratio between NACKs and ACKs as criteria for BFI. Another preferred embodiment of the method according is characterized by that, the value of the Timer (TBFI) and the NACKs-to-ACKs ratio to trigger BFI (RBFI) is (pre)- configured.

Another preferred embodiment of the method according is characterized by that, the value of the Timer ( TBFI) and the NACKs-to-ACKs ratio to trigger BFI is coded.

Another preferred embodiment of the method according is characterized by that, the coding is a table depending on type of services/QoS and/or mobility conditions and/or load conditions.

Another preferred embodiment of the method according is characterized by that, the value of the Timer (TBFI) and the NACKs-to-ACKs ratio to trigger BFI (RBFI) is negotiated between TX and RX between the INITIAL BEAM PAIRING, and indicated and adjusted by the network or by UE.

Another preferred embodiment of the method according is characterized by that, if necessary, the criteria for changing those parameters is dependent to the to implementation within the wireless communication system.

Another preferred embodiment of the method according is characterized by that, the parameters can be configured/associated to one or multiple unicast transmissions.

Another preferred embodiment of the method according is characterized by that, that parameters can be Cell-specific configured/associated.

Another preferred embodiment of the method according is characterized by that, that parameters can be configured/associated based on UE-pairs/groups.

Another preferred embodiment of the method according is characterized by that, that parameters can be configured/associated based on values of the parameters based on UE-aspects, whereby the UE-aspects are TBFI and RBFI Another preferred embodiment of the method according is characterized by that, characterized by, that parameters can be configured/associated based Traffic type and/or QoS.

Another preferred embodiment of the method according is characterized by that, that parameters can be configured/associated based Geographic zones.

Another preferred embodiment of the method according is characterized by that, that parameters can be configured/associated based Mobility condition.

Another preferred embodiment of the method according is characterized by that the parameters can be configured/associated based Type of UE and/or the capabilities of the UE.

Another preferred embodiment of the method according is characterized by that the parameters can be configured/associated based on several downlink schemes, whereby the several downlink schemes can be SIB and/or RRC within FR2 licensed spectrum.

Another preferred embodiment of the method according is characterized by that the parameters can be configured/associated is negotiated from predefined sets in the unicast link establishment.

A preferred embodiment is an apparatus for Beam Failure indication for Sidelink, comprising a wireless transceiver, a processor coupled with a memory in which computer program instructions are stored, said instructions being configured to implement steps of the claims 1 to 16.

A preferred embodiment is an user equipment (UE) comprising an apparatus according to claim 16, whereby the value of the Timer (TBFI) and the NACKs-to-ACKs ratio to trigger BFI (RBFI) cis indicated and adjusted by UE. A preferred embodiment is a Base station gNB, comprising an apparatus according to claim 16, whereby the value of the Timer (TBFI) and the NACKs-to-ACKs ratio to trigger BFI (RBFI) cis indicated and adjusted by Base station gNB.

A preferred embodiment wireless communication system, wherein the gNB, according to claim 19 comprises a processor coupled with a memory in which computer program instructions are stored, said instructions being configured to implement steps of claims 1 to 16, wherein the user equipment (UE) according to claim 18 comprises a processor coupled with a memory in which computer program instructions are stored, said instructions being configured to implement steps of the claims 1 to 16.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is showing the mobility management scenaria

FIG. 2 is showing BFI determination process

FIG. 3 is showing the flow of the method

DETAILED DESCRIPTION

Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following description.

In some embodiments, a more general term “network node” may be used and may correspond to any type of radio network node or any network node, which communicates with a UE (directly or via another node) and/or with another network node. Examples of network nodes are NodeB, MeNB, ENB, a network node belonging to MCG or SCG, base station (BS), multi-standard radio (MSR) radio node such as MSR BS, eNodeB, gNodeB, network controller, radio network controller (RNC), base station controller (BSC), relay, donor node controlling relay, base transceiver station (BTS), access point (AP), transmission points, transmission nodes, RRU, RRH, nodes in distributed antenna system (DAS), core network node (e.g. Mobile Switching Center (MSC), Mobility Management Entity (MME), etc), Operations & Maintenance (O&M), Operations Support System (OSS), Self Optimized Network (SON), positioning node (e.g. Evolved- Serving Mobile Location Centre (E-SMLC)), Minimization of Drive Tests (MDT), test equipment (physical node or software), etc.

In some embodiments, the non-limiting term user equipment (UE) or wireless device may be used and may refer to any type of wireless device communicating with a network node and/or with another UE in a cellular or mobile communication system. Examples of UE are target device, device to device (D2D) UE, machine type UE or UE capable of machine to machine (M2M) communication, PDA, PAD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, UE category Ml, UE category M2, ProSe UE, V2V UE, V2X UE, etc.

Additionally, terminologies such as base station/gNodeB and UE should be considered non-limiting and do in particular not imply a certain hierarchical relation between the two; in general, “gNodeB” could be considered as device 1 and “UE” could be considered as device 2 and these two devices communicate with each other over some radio channel. And in the following the transmitter or receiver could be either gNodeB (gNB), or UE.

As will be appreciated by one skilled in the art, aspects of the embodiments may be embodied as a system, apparatus, method, or program product. Accordingly, embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects.

For example, the disclosed embodiments may be implemented as a hardware circuit comprising custom very-large-scale integration (“VLSI”) circuits or gate arrays, off- the-shelf semiconductors such as logic chips, transistors, or other discrete components. The disclosed embodiments may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices, or the like. As another example, the disclosed embodiments may include one or more physical or logical blocks of executable code which may, for instance, be organized as an object, procedure, or function.

Furthermore, embodiments may take the form of a program product embodied in one or more computer readable storage devices storing machine readable code, computer readable code, and/or program code, referred hereafter as code. The storage devices may be tangible, non- transitory, and/or non-transmission. The storage devices may not embody signals. In a certain embodiment, the storage devices only employ signals for accessing code.

Any combination of one or more computer readable medium may be utilized. The computer readable medium may be a computer readable storage medium. The computer readable storage medium may be a storage device storing the code. The storage device may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

More specific examples (a non-exhaustive list) of the storage device would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random-access memory (“RAM”), a read-only memory (“ROM”), an erasable programmable read-only memory (“EPROM” or Flash memory), a portable compact disc readonly memory (“CD-ROM”), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device.

Code for carrying out operations for embodiments may be any number of lines and may be written in any combination of one or more programming languages including an object- oriented programming language such as Python, Ruby, Java, Smalltalk, C++, or the like, and conventional procedural programming languages, such as the “C” programming language, or the like, and/or machine languages such as assembly languages. The code may execute entirely on the user’s computer, partly on the user’s computer, as a stand-alone software package, partly on the user’s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user’s computer through any type of network, including a local area network (“LAN”), wireless LAN (“WLAN”), or a wide area network (“WAN”), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider (“ISP”)).

Furthermore, the described features, structures, or characteristics of the embodiments may be combined in any suitable manner. In the following description, numerous specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., to provide a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that embodiments may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of an embodiment. Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean “one or more but not all embodiments” unless expressly specified otherwise. The terms “including,” “comprising,” “having,” and variations thereof mean “including but not limited to,” unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms “a,” “an,” and “the” also refer to “one or more” unless expressly specified otherwise.

Aspects of the embodiments are described below with reference to schematic flowchart diagrams and/or schematic block diagrams of methods, apparatuses, systems, and program products according to embodiments. It will be understood that each block of the schematic flowchart diagrams and/or schematic block diagrams, and combinations of blocks in the schematic flowchart diagrams and/or schematic block diagrams, can be implemented by code. This code may be provided to a processor of a general-purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the fimctions/acts specified in the flowchart diagrams and/or block diagrams.

The code may also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the storage device produce an article of manufacture including instructions which implement the function/act specified in the flowchart diagrams and/or block diagrams. The code may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other devices to produce a computer implemented process such that the code which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart diagrams and/or block diagrams.

The flowchart diagrams and/or block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of apparatuses, systems, methods, and program products according to various embodiments. In this regard, each block in the flowchart diagrams and/or block diagrams may represent a module, segment, or portion of code, which includes one or more executable instructions of the code for implementing the specified logical function(s).

It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more blocks, or portions thereof, of the illustrated Figures.

Although various arrow types and line types may be employed in the flowchart and/or block diagrams, they are understood not to limit the scope of the corresponding embodiments. Indeed, some arrows or other connectors may be used to indicate only the logical flow of the depicted embodiment. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of the depicted embodiment. It will also be noted that each block of the block diagrams and/or flowchart diagrams, and combinations of blocks in the block diagrams and/or flowchart diagrams, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and code. The description of elements in each figure may refer to elements of proceeding figures. Like numbers refer to like elements in all figures, including alternate embodiments of like elements.

The detailed description set forth below, with reference to annexed drawings, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. Although terminology from 3GPP 5G NR may be used in this disclosure to exemplify embodiments herein, this should not be seen as limiting the scope of the disclosure.

The disclosure is related to wireless communication system, which may be for example a 5G NR wireless communication system. More specifically, it represents a RAN of the wireless communication system, which is used exchange data with UEs via radio signals. For example, the RAN may send data to the UEs (downlink, DL), for instance data received from a core network (CN). The RAN may also receive data from the UEs (uplink, UL), which data may be forwarded to the CN.

In the examples illustrated, the RAN comprises one base station, BS. Of course, the RAN may comprise more than one BS to increase the coverage of the wireless communication system. Each of these BSs may be referred to as NB, eNodeB (or eNB), gNodeB (or gNB, in the case of a 5G NR wireless communication system), an access point or the like, depending on the wireless communication standard(s) implemented.

The UEs are located in a coverage of the BS. The coverage of the BS corresponds for example to the area in which UEs can decode a PDCCH transmitted by the BS.

An example of a wireless device suitable for implementing any method, discussed in the present disclosure, performed at a UE corresponds to an apparatus that provides wireless connectivity with the RAN of the wireless communication system, and that can be used to exchange data with said RAN. Such a wireless device may be included in a UE. The UE may for instance be a cellular phone, a wireless modem, a wireless communication device, a handheld device, a laptop computer, or the like. The UE may also be an Internet of Things (loT) equipment, like a wireless camera, a smart sensor, a smart meter, smart glasses, a vehicle (manned or unmanned), a global positioning system device, etc., or any other equipment that may run applications that need to exchange data with remote recipients, via the wireless device.

The wireless device comprises one or more processors and one or more memories. The one or more processors may include for instance a central processing unit (CPU), a digital signal processor (DSP), a field-programmable gate array (FPGA), an application specific integrated circuit (ASIC), etc. The one or more memories may include any type of computer readable volatile and non-volatile memories (magnetic hard disk, solid-state disk, optical disk, electronic memory, etc.). The one or more memories may store a computer program product, in the form of a set of programcode instructions to be executed by the one or more processors to implement all or part of the steps of a method for exchanging data, performed at a UE’s side, according to any one of the embodiments disclosed herein.

The wireless device can comprise also a main radio, MR, unit. The MR unit corresponds to a main wireless communication unit of the wireless device, used for exchanging data with BSs of the RAN using radio signals. The MR unit may implement one or more wireless communication protocols, and may for instance be a 3G, 4G, 5G, NR, WiFi, WiMax, etc. transceiver or the like. In preferred embodiments, the MR unit corresponds to a 5G NR wireless communication unit.

FIG. 1 is showing the mobility management scenario, which was already described.

FIG. 2 is showing BFI determination process. Basically spoken the process defines (re)Configuration of criteria. The reconfiguration determines the BFI criterion, which is the core of this application. The event is the declaration of beam failure indication (BFI). The declaration of beam failure indication (BFI) are used for the beam recovery procedures, this means that when beam failure is declared, recovery procedures are triggered.

FIG. 3 is indication showing the flow of the method. According to the application, the solution is based on Sidelink BFI is triggered based on PSFCH carrying sidelink HARQ feedback, which means BFI can be declared at transmitter side. Unicast communication is established, and feedback (HARQ: ACK or NACK) is expected at transmitted side. The value of the Timer ( TBFI) and the NACKs-to-ACKs ratio to trigger BFI (RBFI) exact usage of these parameters will be is clarified in the following paragraphes and can be (pre)-configured and/or coded in the specification e.g., a table depending on type of services/QoS, mobility conditions, load conditions, etc., and/or negotiated between TX and RX between the INITIAL BEAM PAIRING, and indicated and adjusted by the network or by UE, if necessary (criteria for changing those parameters belongs to implementation). The aforementioned parameters can be configured/associated to one or multiple unicast transmissions.

Unicast transmissions (PSSCH) is send from TX to a RX with oner or more transmissions whereby

• to is set when the first NACK is received.

• If a NACK is received NNACK = NNACK +1

• If ACK is received NACK = NACK +1 and fNACK: first NACK after to (#NACK > to)

CONDITION CHECKPOINT is

At to + TBFI TX checks whether M > RBFI.

• Yes

• BFI is triggered

• TBFI is reset

• No

• to <- fNACK (if no NACK timer is not triggered)

• TBFI is reset The RX sends Unicast/feedback transmissions (PSFCH) with ACK or NACK.

HARQ burst: several ACKs and/or NACKs are transmitted by RX.

The criterion M is defined by:

This formula captures the idea of checking a ratio between ACKs and NACKs. Alternatively, simply the number of NACKs within the timer is also possible and straightforward (a different criterion). The timer could overlap (for continuous check) or simply reset in a back-to-back manner. M is only checked after Timer expires.

Mechanisms to adjust/modify the “BFI CRITERION” is Cell-specific and I or UE- pairs/groups.

Values of the parameters based on UE-aspects: 7BFI and RBFI like Traffic type or QoS, Geographic zones, Mobility condition, Type of UE (capabilities)

Signaling mechanisms has Specification Impact. The (re)Configuration, at least can be done in two modes: Mode 1 : several downlink schemes, e.g., SIB, RRC (FR2 licensed spectrum). Mode 2: negotiated (from predefined sets) in the unicast link establishment.

The described solution in the application is that, that ratio and timer combination provides a flexible and reliable way to control/monitor beam quality. Abbreviations

ACK Acknowledgement

BFD Beam Failure Detection

BFI Beam Failure Indication/lnstance

BFR Beam Failure Recovery

BFRQ BFR Request

BFRR BFR Response

BWP Bandwidth part

CBD Candidate Beam Determination

CBG Code block group

CLI Cross Link Interference

CP Cyclic prefix

CPU CSI processing unit

CQI Channel quality indicator

CRB Common resource block

CRC Cyclic redundancy check

CRI CSI-RS Resource Indicator

CSI Channel state information

CSI-RS Channel state information reference signal

CSI-RSRP CSI reference signal received power

CSI-RSRQ CSI reference signal received quality

CSI-SINR CSI signal-to-noise and interference ratio

CW Codeword

DCI Downlink control information

DL Downlink

DM-RS Demodulation reference signals

DRX Discontinuous Reception

EPRE Energy per resource element

HARQ Hybrid automatic repeat request

IAB-MT Integrated Access and Backhaul - Mobile Terminal

L1-RSRP Layer 1 reference signal received power

LI Layer Indicator MCS Modulation and coding scheme NACK Negative Acknowledgement PDCCH Physical downlink control channel PDSCH Physical downlink shared channel PMI Precoding Matrix Indicator PRB Physical resource block PRG Precoding resource block group PRS Positioning reference signal PSS Primary Synchronisation signal PT-RS Phase-tracking reference signal

PUCCH Physical uplink control channel QCL Quasi co-location RB Resource block RBG Resource block group Rl Rank Indicator

RIV Resource indicator value RS Reference signal

SCI Sidelink control information SLIV Start and length indicator value SR Scheduling Request SRS Sounding reference signal SS Synchronisation signal SS-RSRP SS reference signal received power SS-RSRQ SS reference signal received quality SSS Secondary Synchronisation signal SS-SINR SS signal-to-noise and interference ratio

TB Transport Block TCI Transmission Configuration Indicator TDM Time division multiplexing UE User equipment UL Uplink

Claims

1 . Method for Beam Failure indication for Sidelink in a wireless communication system, whereby Sidelink BFI is triggered based on PSFCH carrying sidelink HARQ feedback and BFI is declared at transmitter side, Unicast communication is established, and feedback, which is HARQ with ACK or NACK is expected to be received at transmitter side, characterized by, that a timer (TBFI) is established and used to verify the ratio between NACKs and ACKs as criteria for BFI.

2. The method according to claim 1 , whereby the value of the Timer (TBFI) and the NACKs-to-ACKs ratio to trigger BFI (RBFI) is configured and/or pre configured.

3. The method according to claim 1 or 2, whereby the value of the Timer ( TBFI) and the NACKs-to-ACKs ratio to trigger BFI is hard-coded in the specifications.

4. The method according to claim 1 to 3, the coding is a table depending on type of services/QoS and/or mobility conditions and/or load conditions.

5. The method according to claim 1 to 4, whereby the value of the Timer ( TBFI) and the NACKs-to-ACKs ratio to trigger BFI (RBFI) is negotiated between TX and RX between the INITIAL BEAM PAIRING, and indicated and adjusted by the network or by UE.

6. The method according to any previous claims, characterized by, that if necessary, the criteria for changing those parameters is dependent to the to implementation within the wireless communication system.

7. The method according to any previous claims, characterized by, that parameters can be configured/associated to one or multiple unicast transmissions.

8. The method according to any previous claims, characterized by, that parameters can be Cell-specific configured/associated.

9. The method according to any previous claims, characterized by, that parameters can be configured/associated based on UE-pairs/groups.

10. The method according to any previous claims, characterized by, that parameters can be configured/associated based on values of the parameters based on UE- aspects, whereby the UE-aspects are TBFI and RBFI

11. The method according to any previous claims, characterized by, that parameters can be configured/associated based Traffic type and/or QoS.

12. The method according to any previous claims, characterized by, that parameters can be configured/associated based Geographic zones.

13. The method according to any previous claims, characterized by, that parameters can be configured/associated based Mobility condition.

14. The method according to any previous claims, characterized by, that parameters can be configured/associated based Type of UE and/or the capabilities of the UE.

15. The method according to any previous claims, characterized by, that parameters can be configured/associated based on several downlink schemes, whereby the several downlink schemes can be SIB and/or RRC within FR2 licensed spectrum.

16. The method according to any previous claims 1 to 14, characterized by, that parameters can be configured/associated is negotiated from predefined sets in the unicast link establishment.

17. Apparatus for Beam Failure indication for Sidelink, comprising a wireless transceiver, a processor coupled with a memory in which computer program instructions are stored, said instructions being configured to implement steps of the claims 1 to 16.

18. User Equipment (UE) comprising an apparatus according to claim 16, whereby the value of the Timer ( TBFI) and the NACKs-to-ACKs ratio to trigger BFI (RBFI) cis indicated and adjusted by UE.

19. Base station gNB, comprising an apparatus according to claim 16, whereby the value of the Timer ( TBFI) and the NACKs-to-ACKs ratio to trigger BFI (RBFI) cis indicated and adjusted by Base station gNB.

20. Wireless communication system, wherein the gNB, according to claim 19 comprises a processor coupled with a memory in which computer program instructions are stored, said instructions being configured to implement steps of claims 1 to 16: wherein the user equipment (UE) according to claim 18 comprises a processor coupled with a memory in which computer program instructions are stored, said instructions being configured to implement steps of the claims 1 to 16.