Method And Apparatus For Transmitting Sidelink Control Information Patent Application (2024)

U.S. patent application number 17/604965 was filed with the patent office on 2022-07-14 for method and apparatus for transmitting sidelink control information.The applicant listed for this patent is LG Electronics Inc.. Invention is credited to Jongyoul LEE, Youngdae LEE, Giwon PARK, Hanbyul SEO.

METHOD AND APPARATUS FOR TRANSMITTING SIDELINK CONTROLINFORMATION

Abstract

A method and apparatus for transmitting sidelink controlinformation in a wireless communication system is provided. Awireless device determines that a sidelink (SL) resource has notbeen reserved within a time period related to transmission ofsidelink control information (SCI), and triggers SL resourcereservation for transmission of the SCI.

Foreign Application Data

Claims

1. A method for a wireless device in a wireless communicationsystem, the method comprising: determining that a sidelink (SL)resource has not been reserved within a time period related totransmission of sidelink control information (SCI); and triggeringSL resource reservation for transmission of the SCI.

2. The method of claim 1, wherein the time period is a SCIperiod.

3. The method of claim 1, wherein the SL resource has not beenreserved within the period after latest transmission of theSCI.

4. The method of claim 1, wherein the method further includestransmitting the SCI by using the SL resource reserved based on theSL resource reservation.

5. The method of claim 4, wherein the SL resource is reserved on aresource pool with a specific priority.

6. The method of claim 5, wherein the SCI indicates the specificpriority.

7. The method of claim 5, wherein the specific priority is apriority configured by a network and/or a pre-configuration storedin the first wireless device.

8. The method of claim 5, wherein the specific priority is ahighest priority or a lowest priority.

9. The method of claim 5, wherein the specific priority indicatestransmission of the SCI without transmitting sidelink data.

10. The method of claim 1, wherein the SCI indicates no sidelinkshared channel (SL-SCH) transmission.

11. The method of claim 1, wherein the SCI indicates a specificidentifier (ID) which indicate no SL-SCH transmission.

12. The method of claim 12, wherein the specific ID includes atleast one of a source ID, a destination ID and/or an ID associatedwith a link between the first wireless device and the secondwireless device.

13. The method of claim 1, wherein the wireless device is incommunication with at least one of a mobile device, a network,and/or autonomous vehicles other than the wireless device.

14. A wireless device in a wireless communication system, thewireless device comprising: at least one transceiver; at leastprocessor; and at least one computer memory operably connectable tothe at least one processor and storing instructions that, based onbeing executed by the at least one processor, perform operationscomprising: determining that a sidelink (SL) resource has not beenreserved within a time period related to transmission of sidelinkcontrol information (SCI); and triggering SL resource reservationfor transmission of the SCI.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a method and apparatus fortransmitting sidelink control information.

BACKGROUND

[0002] Wireless communication systems generally aim to reduce costsfor users and providers, improve service quality, and expand andimprove coverage and system capacity. To achieve these goals, insome scenarios, wireless communication systems are designed toreduced cost per bit, increased service availability, flexible useof a frequency band, a simple structure, an open interface, andadequate power consumption of a terminal as an upper-levelrequirement.

SUMMARY

[0003] An aspect of the present disclosure is to provide a methodand apparatus for transmitting sidelink control information withina time period.

[0004] In an aspect, a method for a wireless device in a wirelesscommunication system is provided. The method includes determiningthat a sidelink (SL) resource has not been reserved within a timeperiod related to transmission of sidelink control information(SCI), and triggering SL resource reservation for transmission ofthe SCI.

[0005] In another aspect, an apparatus for implementing the abovemethod is provided.

[0006] The present disclosure can have various advantageouseffects.

[0007] For example, a UE can transmit control information (e.g.,SCI) for sidelink management within appropriate time period.

[0008] For example, a UE can reserve a resource and transmitcontrol information (e.g., SCI) for a direct link with other UE, inparticular when the UE has no data to be transmitted to the otherUE.

[0009] For example, the system can reliably manage a direct linkbetween two UEs performing sidelink communication.

[0010] Advantageous effects which can be obtained through specificembodiments of the present disclosure are not limited to theadvantageous effects listed above. For example, there may be avariety of technical effects that a person having ordinary skill inthe related art can understand and/or derive from the presentdisclosure. Accordingly, the specific effects of the presentdisclosure are not limited to those explicitly described herein,but may include various effects that may be understood or derivedfrom the technical features of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 shows an example of a wireless communication systemto which implementations of the present disclosure can beapplied.

[0012] FIG. 2 shows a block diagram of an example of a user planeprotocol stack t to which implementations of the present disclosurecan be applied.

[0013] FIG. 3 shows a block diagram of an example of a controlplane protocol stack to which implementations of the presentdisclosure can be applied.

[0014] FIG. 4 shows a frame structure in a 3GPP based wirelesscommunication system to which implementations of the presentdisclosure can be applied.

[0015] FIG. 5 shows a data flow example in the 3GPP NR system towhich implementations of the present disclosure can be applied.

[0016] FIG. 6 shows an example of a communication system to whichimplementations of the present disclosure can be applied.

[0017] FIG. 7 shows an example of wireless devices to whichimplementations of the present disclosure can be applied.

[0018] FIG. 8 shows an example of a wireless device to whichimplementations of the present disclosure can be applied.

[0019] FIG. 9 shows another example of wireless devices to whichimplementations of the present disclosure can be applied.

[0020] FIG. 10 shows an example of UE to which implementations ofthe present disclosure can be applied.

[0021] FIGS. 11 and 12 show an example of PC5 protocol stacks towhich implementations of the present disclosure can be applied.

[0022] FIG. 13 shows an example of a method for a wireless deviceto which implementations of the present disclosure can beapplied.

[0023] FIG. 14 shows an example of a method for performing sidelinkcommunication for a UE to which implementations of the presentdisclosure can be applied.

DETAILED DESCRIPTION

[0024] In the present disclosure, "A or B" may mean "only A", "onlyB", or "both A and B". In other words, "A or B" in the presentdisclosure may be interpreted as "A and/or B". For example, "A, Bor C" in the present disclosure may mean "only A", "only B", "onlyC", or "any combination of A, B and C".

[0025] In the present disclosure, slash (/) or comma (,) may mean"and/or". For example, "A/B" may mean "A and/or B". Accordingly,"A/B" may mean "only A", "only B", or "both A and B". For example,"A, B, C" may mean "A, B or C".

[0026] In the present disclosure, "at least one of A and B" maymean "only A", "only B" or "both A and B". In addition, theexpression "at least one of A or B" or "at least one of A and/or B"in the present disclosure may be interpreted as same as "at leastone of A and B".

[0027] In addition, in the present disclosure, "at least one of A,B and C" may mean "only A", "only B", "only C", or "any combinationof A, B and C". In addition, "at least one of A, B or C" or "atleast one of A, B and/or C" may mean "at least one of A, B andC".

[0028] Also, parentheses used in the present disclosure may mean"for example". In detail, when it is shown as "control information(PDCCH)", "PDCCH" may be proposed as an example of "controlinformation". In other words, "control information" in the presentdisclosure is not limited to "PDCCH", and "PDDCH" may be proposedas an example of "control information". In addition, even whenshown as "control information (i.e., PDCCH)", "PDCCH" may beproposed as an example of "control information".

[0029] Technical features that are separately described in onedrawing in the present disclosure may be implemented separately orsimultaneously.

[0030] Although not limited thereto, various descriptions,functions, procedures, suggestions, methods and/or operationalflowcharts of the present disclosure disclosed herein can beapplied to various fields requiring wireless communication and/orconnection (e.g., 5G) between devices.

[0031] Vehicle-to-everything (V2X) communication is thecommunication of information from a vehicle to an entity that mayaffect the vehicle, and vice versa. Examples of V2X includevehicle-to-infrastructure (V2I), vehicle-to-network (V2N),vehicle-to-vehicle (V2V), vehicle-to-pedestrian (V2P),vehicle-to-device (V2D), and vehicle-to-grid (V2G).

[0032] V2X systems may be designed to achieve various objectives,such as road safety, traffic efficiency, and energy savings. V2Xcommunication technology may be classified into two types,depending on the underlying technology: wireless local area network(WLAN)-based V2X, and cellular-based V2X.

[0033] The 3rd generation partnership project (3GPP) long-termevolution (LTE) is a technology designed to enable high-speedpacket communications. In addition, the internationaltelecommunication union (ITU) and 3GPP have developed technicalstandards for new radio (NR) systems. In doing so, technology isbeing identified and developed to successfully standardize the newradio access technology (RAT), in order to timely satisfy bothurgent market needs, as well as longer-term goals and requirementsset forth by the ITU radio communication sector (ITU-R)international mobile telecommunications (IMT)-2020 process. In somescenarios, NR is being designed to use any spectrum band ranging atleast up to 100 GHz, which may be made available for wirelesscommunications even in a more distant future.

[0034] The NR targets a technical framework addressing varioususage scenarios, requirements, and deployment scenarios, such as,for example, enhanced mobile broadband (eMBB), massivemachine-type-communications (mMTC), ultra-reliable and low latencycommunications (URLLC), etc.

[0035] In some systems, one or more technical features describedbelow may be compatible with one or more technical standards, suchas those used by a communication standard by the 3GPPstandardization organization, a communication standard by theinstitute of electrical and electronics engineers (IEEE), etc. Forexample, the communication standards by the 3GPP standardizationorganization include LTE and/or evolution of LTE systems. Theevolution of LTE systems includes LTE-advanced (LTE-A), LTE-A Pro,and/or 5G NR. The communication standard by the IEEEstandardization organization includes a wireless local area network(WLAN) system such as IEEE 802.11a/b/g/n/ac/ax. The above systemuses various multiple access technologies such as orthogonalfrequency division multiple access (OFDMA) and/or single carrierfrequency division multiple access (SC-FDMA) for downlink (DL)and/or uplink (DL). For example, only OFDMA may be used for DL andonly SC-FDMA may be used for UL. Alternatively, OFDMA and SC-FDMAmay be used for DL and/or UL.

[0036] For convenience of description, implementations of thepresent disclosure are mainly described in regards to a 3GPP basedwireless communication system. However, the technical features ofthe present disclosure are not limited thereto. For example,although the following detailed description is given based on amobile communication system corresponding to a 3GPP based wirelesscommunication system, aspects of the present disclosure that arenot limited to 3GPP based wireless communication system areapplicable to other mobile communication systems.

[0037] For terms and technologies which are not specificallydescribed among the terms of and technologies employed in thepresent disclosure, the wireless communication standard documentspublished before the present disclosure may be referenced.

[0038] Hereinafter, the present disclosure will be described inmore detail with reference to drawings. The same reference numeralsin the following drawings and/or descriptions may refer to the sameand/or corresponding hardware blocks, software blocks, and/orfunctional blocks unless otherwise indicated.

[0039] FIG. 1 shows an example of a wireless communication systemto which implementations of the present disclosure can beapplied.

[0040] Referring to FIG. 1, the wireless communication systemincludes one or more user equipment (UE), a next-generation RAN(NG-RAN) and a 5th generation core network (5GC). The NG-RANconsists of at least one NG-RAN node. The NG-RAN node consists ofat least one gNB and/or at least one ng-eNB. The gNB provides NRuser plane and control plane protocol terminations towards the UE.The ng-eNB provides E-UTRA user plane and control plane protocolterminations towards the UE.

[0041] The 5GC includes an access and mobility management function(AMF), a user plane function (UPF) and a session managementfunction (SMF). The AMF hosts various functions, such as, forexample, non-access stratum (NAS) security, idle state mobilityhandling, evolved packet system (EPS) bearer control, etc. The UPFhosts various functions, such as, for example, mobility anchoring,protocol data unit (PDU) handling, etc. The SMF hosts variousfunctions, such as, for example, UE IP address allocation, PDUsession control, etc.

[0042] The gNBs and ng-eNBs are interconnected with each other byan interface, such as the Xn interface. The gNBs and ng-eNBs arealso connected by NG interfaces to the 5GC, for example, to the AMFby the NG-C interface and to the UPF by the NG-U interface.

[0043] An example of a protocol structure between network entitiesdescribed above is described. In the example of FIG. 1, layers of aradio interface protocol between the UE and the network (e.g.NG-RAN) may be classified into a first layer (L1), a second layer(L2), and a third layer (L3), for example based on the lower threelayers of the open system interconnection (OSI) model.

[0044] FIG. 2 shows a block diagram of an example of a user planeprotocol stack t to which implementations of the present disclosurecan be applied. FIG. 3 shows a block diagram of an example of acontrol plane protocol stack to which implementations of thepresent disclosure can be applied.

[0045] Referring to the examples of FIG. 2 and FIG. 3, a physical(PHY) layer belongs to L1. The PHY layer offers informationtransfer services to the media access control (MAC) sublayer andhigher layers. For example, the PHY layer offers transport channelsto the MAC sublayer, and data between the MAC sublayer and the PHYlayer is transferred via the transport channels. Between differentPHY layers, e.g., between a PHY layer of a transmission side and aPHY layer of a reception side, data is transferred via physicalchannels.

[0046] The MAC sublayer belongs to L2. The services and functionsof the MAC sublayer include, for example, mapping between logicalchannels and transport channels, multiplexing/de-multiplexing ofMAC service data units (SDUs) belonging to one or different logicalchannels into/from transport blocks (TB) delivered to/from thephysical layer on transport channels, scheduling informationreporting, error correction through hybrid automatic repeat request(HARD), priority handling between UEs by dynamic scheduling,priority handling between logical channels of one UE by logicalchannel prioritization (LCP), etc. The MAC sublayer offers to theradio link control (RLC) sublayer logical channels.

[0047] The RLC sublayer belong to L2. In some implementations, theRLC sublayer supports different transmission modes, e.g.,transparent mode(TM), unacknowledged mode (UM), and acknowledgedmode (AM). The different transmission modes may help guaranteevarious quality of services (QoS) required by radio bearers. Theservices and functions of the RLC sublayer may depend on thetransmission mode. For example, in some implementations, the RLCsublayer provides transfer of upper layer PDUs for all three modes,but provides error correction through ARQ for AM only. In someimplementations, such as implementations compatible with LTE/LTE-A,the RLC sublayer provides concatenation, segmentation andreassembly of RLC SDUs (only for UM and AM data transfer) andre-segmentation of RLC data PDUs (only for AM data transfer). InNR, the RLC sublayer provides segmentation (only for AM and UM) andre-segmentation (only for AM) of RLC SDUs and reassembly of SDU(only for AM and UM). In some implementations, the NR does notsupport concatenation of RLC SDUs. The RLC sublayer offers RLCchannels to the packet data convergence protocol (PDCP)sublayer.

[0048] The PDCP sublayer belongs to L2. The services and functionsof the PDCP sublayer for the user plane include, for example,header compression and decompression, transfer of user data,duplicate detection, PDCP PDU routing, retransmission of PDCP SDUs,ciphering and deciphering, etc. The services and functions of thePDCP sublayer for the control plane include, for example, cipheringand integrity protection, transfer of control plane data, etc.

[0049] The service data adaptation protocol (SDAP) sublayer belongsto L2. In some implementations, the SDAP sublayer is only definedin the user plane. The services and functions of SDAP include, forexample, mapping between a QoS flow and a data radio bearer (DRB),and marking QoS flow ID (QFI) in both DL and UL packets. The SDAPsublayer offers QoS flows to 5GC.

[0050] A radio resource control (RRC) layer belongs to L3. In someimplementations, the RRC layer is only defined in the controlplane. The RRC layer controls radio resources between the UE andthe network. For example, the RRC layer exchanges RRC messagesbetween the UE and the BS. The services and functions of the RRClayer include, for example, broadcast of system information relatedto access stratum AS and NAS, paging, establishment, maintenanceand release of an RRC connection between the UE and the network,security functions including key management, establishment,configuration, maintenance and release of radio bearers, mobilityfunctions, QoS management functions, UE measurement reporting andcontrol of the reporting, NAS message transfer to/from NAS from/toUE.

[0051] As such, in some implementations, the RRC layer controlslogical channels, transport channels, and physical channels inrelation to the configuration, reconfiguration, and release ofradio bearers. A radio bearer refers to a logical path provided byL1 (PHY layer) and L2 (MAC/RLC/PDCP/SDAP sublayer) for datatransmission between a UE and a network. In some scenarios, settingthe radio bearer may include defining the characteristics of theradio protocol layer and the channel for providing a specificservice, and setting each specific parameter and operation method.Radio bearers may include signaling RB (SRB) and data RB (DRB). TheSRB is used as a path for transmitting RRC messages in the controlplane, and the DRB is used as a path for transmitting user data inthe user plane.

[0052] An RRC state indicates whether an RRC layer of the UE islogically connected to an RRC layer of the network. In someimplementations, when the RRC connection is established between theRRC layer of the UE and the RRC layer of the network, the UE is inthe RRC_connected state (RRC_CONNECTED); and otherwise, the UE isin the RRC idle state (RRC_IDLE). In implementations compatiblewith NR, the RRC inactive state (RRC_INACTIVE) is additionallyintroduced. The RRC_INACTIVE state may be used for variouspurposes. For example, in some scenarios, massive machine-typecommunications (mMTC) UEs can be efficiently managed inRRC_INACTIVE. When specific conditions are satisfied, transitionscan be made from one of the above three states to others.

[0053] Various operations may be performed according to the RRCstate. For example, in RRC_IDLE, operations such as public landmobile network (PLMN) selection, broadcast of system information(SI), cell re-selection mobility, core network (CN) paging anddiscontinuous reception (DRX) configured by NAS may be performed.The UE may be allocated an identifier (ID) which uniquelyidentifies the UE in a tracking area. In some implementations, noRRC context is stored in the base station.

[0054] As another example, in RRC_CONNECTED, the UE has an RRCconnection with the network. Network-CN connection (bothC/U-planes) is also established for UE. In some implementations,the UE AS context is stored in the network and the UE. The RANknows the cell which the UE belongs to, and the network cantransmit and/or receive data to/from UE. In some implementations,network controlled mobility including measurement is alsoperformed.

[0055] One or more operations that are performed in RRC_IDLE mayalso be performed in RRC_INACTIVE. However, in someimplementations, instead of performing CN paging as in RRC_IDLE,RAN paging may be performed in RRC_INACTIVE. For example, inRRC_IDLE, paging for mobile terminated (MT) data is initiated by acore network and paging area is managed by the core network. InRRC_INACTIVE, paging may be initiated by NG-RAN, and RAN-basednotification area (RNA) is managed by NG-RAN. Further, in someimplementations, instead of DRX for CN paging configured by NAS inRRC_IDLE, DRX for RAN paging is configured by NG-RAN inRRC_INACTIVE. In some implementations, in RRC_INACTIVE, 5GC-NG-RANconnection (both C/U-planes) is established for UE, and the UE AScontext is stored in NG-RAN and the UE. The NG-RAN may know the RNAwhich the UE belongs to.

[0056] The NAS layer is implemented above the RRC layer, as shownin the example of FIG. 3. The NAS control protocol performs variousfunctions, such as, for example, authentication, mobilitymanagement, security control, etc.

[0057] Physical channels, for example as utilized by the PHY layer,may be modulated according to various modulation techniquesutilizing time and frequency as radio resources. For example, thephysical channels may consist of a plurality of orthogonalfrequency division multiplexing (OFDM) symbols in time domain and aplurality of subcarriers in frequency domain. A subframe may beimplemented, which consists of a plurality of OFDM symbols in thetime domain. A resource block may be implemented as a resourceallocation unit, and each resource block may consist of a pluralityof OFDM symbols and a plurality of subcarriers. In addition, eachsubframe may use specific subcarriers of specific OFDM symbols(e.g., the first OFDM symbol) of the corresponding subframe for aspecific purpose, such as for a physical downlink control channel(PDCCH), e.g., an L1/L2 control channel. A transmission timeinterval (TTI) may be implemented as a basic unit of time, forexample as used by a scheduler for resource allocation. The TTI maybe defined in units of one or a plurality of slots, or may bedefined in units of mini-slots.

[0058] Transport channels may be classified according to how andwith what characteristics data are transferred over the radiointerface. For example, DL transport channels include a broadcastchannel (BCH) used for transmitting system information, a downlinkshared channel (DL-SCH) used for transmitting user traffic orcontrol signals, and a paging channel (PCH) used for paging a UE.As another example, UL transport channels include an uplink sharedchannel (UL-SCH) for transmitting user traffic or control signalsand a random access channel (RACH) normally used for initial accessto a cell.

[0059] Different kinds of data transfer services may be offered bythe MAC sublayer. Different logical channel types may be defined bywhat type of information is transferred. In some implementations,logical channels may be classified into two groups: controlchannels and traffic channels.

[0060] Control channels are used for the transfer of control planeinformation only, according to some implementations. The controlchannels may include, for example, a broadcast control channel(BCCH), a paging control channel (PCCH), a common control channel(CCCH) and a dedicated control channel (DCCH). The BCCH is a DLchannel for broadcasting system control information. The PCCH is DLchannel that transfers paging information, system informationchange notifications. The CCCH is a channel for transmittingcontrol information between UEs and network. In someimplementations, the CCCH is used for UEs having no RRC connectionwith the network. The DCCH is a point-to-point bi-directionalchannel that transmits dedicated control information between a UEand the network. In some implementations, the DCCH is used by UEshaving an RRC connection.

[0061] Traffic channels are used for the transfer of user planeinformation only, according to some implementations. The trafficchannels include, for example, a dedicated traffic channel (DTCH).The DTCH is a point-to-point channel, dedicated to one UE, for thetransfer of user information. In some implementations, the DTCH canexist in both UL and DL.

[0062] In some scenarios, mappings may be implemented between thelogical channels and transport channels. For example, in DL, BCCHcan be mapped to BCH, BCCH can be mapped to DL-SCH, PCCH can bemapped to PCH, CCCH can be mapped to DL-SCH, DCCH can be mapped toDL-SCH, and DTCH can be mapped to DL-SCH. As another example, inUL, CCCH can be mapped to UL-SCH, DCCH can be mapped to UL-SCH, andDTCH can be mapped to UL-SCH.

[0063] FIG. 4 shows a frame structure in a 3GPP based wirelesscommunication system to which implementations of the presentdisclosure can be applied.

[0064] The frame structure shown in FIG. 4 is purely exemplary andthe number of subframes, the number of slots, and/or the number ofsymbols in a frame may be variously changed. In the 3GPP basedwireless communication system, OFDM numerologies (e.g., subcarrierspacing (SCS), TTI duration) may be differently configured betweena plurality of cells aggregated for one UE. For example, if a UE isconfigured with different SCSs for cells aggregated for the cell,an (absolute time) duration of a time resource (e.g., a subframe, aslot, or a TTI) including the same number of symbols may bedifferent among the aggregated cells. Herein, symbols may includeOFDM symbols (or CP-OFDM symbols), SC-FDMA symbols (or discreteFourier transform-spread-OFDM (DFT-s-OFDM) symbols).

[0065] Referring to FIG. 4, downlink and uplink transmissions areorganized into frames. Each frame has T.sub.f=10MS duration. Eachframe is divided into two half-frames, where each of thehalf-frames has 5 ms duration. Each half-frame consists of 5subframes, where the duration T.sub.sf per subframe is 1 ms. Eachsubframe is divided into slots and the number of slots in asubframe depends on a subcarrier spacing. Each slot includes 14 or12 OFDM symbols based on a cyclic prefix (CP). In a normal CP, eachslot includes 14 OFDM symbols and, in an extended CP, each slotincludes 12 OFDM symbols. The numerology is based on exponentiallyscalable subcarrier spacing .DELTA..sub.f=2.sup.u*15 kHz.

[0066] Table 1 shows the number of OFDM symbols per slotN.sup.slot.sub.symbol, the number of slots per frameN.sup.frame,u.sub.slot, and the number of slots per subframeN.sup.subframe,u.sub.slot for the normal CP, according to thesubcarrier spacing .DELTA.f=2.sup.u*15 kHz.

TABLE-US-00001 TABLE 1 u N.sup.slot.sub.symb N.sup.frame,u.sub.slot N.sup.subframe, u.sub.slot 0 14 10 1 1 14 20 2 2 14 40 43 14 80 8 4 14 160 16

[0067] Table 2 shows the number of OFDM symbols per slotN.sup.slot.sub.symb, the number of slots per frameN.sup.frame,u.sub.slot, and the number of slots per subframeN.sup.subframe,u.sub.slot for the extended CP, according to thesubcarrier spacing .DELTA.f2.sup.u*15 kHz.

TABLE-US-00002 TABLE 2 u N.sup.slot.sub.symb N.sup.frame,u.sub.slot N.sup.subframe, u.sub.slot 2 12 40 4

[0068] A slot includes plural symbols (e.g., 14 or 12 symbols) inthe time domain. For each numerology (e.g., subcarrier spacing) andcarrier, a resource grid of N.sup.size,u.sub.grid,x*N.sup.RB.sub.scsubcarriers and N.sup.subframe,u.sub.symb OFDMsymbols is defined,starting at common resource block (CRB)N.sup.start,u.sub.gridindicated by higher-layer signaling (e.g., RRC signaling), whereN.sup.size,u.sub.grid,x is the number of resource blocks (RBs) inthe resource grid and the subscript x is DL for downlink and UL foruplink. N.sup.RB.sub.sc is the number of subcarriers per RB. In the3GPP based wireless communication system, N.sup.RB.sub.sc is 12generally. There is one resource grid for a given antenna port p,subcarrier spacing configuration u, and transmission direction (DLor UL). The carrier bandwidth N.sup.size,u.sub.grid for subcarrierspacing configuration u is given by the higher-layer parameter(e.g., RRC parameter). Each element in the resource grid for theantenna port p and the subcarrier spacing configuration u isreferred to as a resource element (RE) and one complex symbol maybe mapped to each RE. Each RE in the resource grid is uniquelyidentified by an index k in the frequency domain and an index lrepresenting a symbol location relative to a reference point in thetime domain. In the 3GPP based wireless communication system, an RBis defined by 12 consecutive subcarriers in the frequencydomain.

[0069] In the 3GPP NR system, RBs are classified into CRBs andphysical resource blocks (PRBs). CRBs are numbered from 0 andupwards in the frequency domain for subcarrier spacingconfiguration u. The center of subcarrier 0 of CRB 0 for subcarrierspacing configuration u coincides with `point A` which serves as acommon reference point for resource block grids. In the 3GPP NRsystem, PRBs are defined within a bandwidth part (BWP) and numberedfrom 0 to N.sup.size.sub.BWP,i-1, where i is the number of thebandwidth part. The relation between the physical resource blocknPRB in the bandwidth part i and the common resource blockn.sub.CRB is as follows: n.sub.PRB=n.sub.CRB+N.sup.size.sub.BWP,i,where N.sup.size.sub.BWP,i is the common resource block wherebandwidth part starts relative to CRB 0. The BWP includes aplurality of consecutive RBs. A carrier may include a maximum of N(e.g., 5) BWPs. A UE may be configured with one or more BWPs on agiven component carrier. Only one BWP among BWPs configured to theUE can active at a time. The active BWP defines the UE's operatingbandwidth within the cell's operating bandwidth.

[0070] The NR frequency band may be defined as two types offrequency range, i.e., FR1 and FR2. The numerical value of thefrequency range may be changed. For example, the frequency rangesof the two types (FR1 and FR2) may be as shown in Table 3 below.For ease of explanation, in the frequency ranges used in the NRsystem, FR1 may mean "sub 6 GHz range", FR2 may mean "above 6 GHzrange," and may be referred to as millimeter wave (mmW).

TABLE-US-00003 TABLE 3 Frequency Range Corresponding designationfrequency range Subcarrier Spacing FR1 450 MHz-6000 MHz 15, 30, 60kHz FR2 24250 MHz-52600 MHz 60, 120, 240 kHz

[0071] As mentioned above, the numerical value of the frequencyrange of the NR system may be changed. For example, FR1 may includea frequency band of 410 MHz to 7125 MHz as shown in Table 4 below.That is, FR1 may include a frequency band of 6 GHz (or 5850, 5900,5925 MHz, etc.) or more. For example, a frequency band of 6 GHz (or5850, 5900, 5925 MHz, etc.) or more included in FR1 may include anunlicensed band. Unlicensed bands may be used for a variety ofpurposes, for example for communication for vehicles (e.g.,autonomous driving).

TABLE-US-00004 TABLE 4 Frequency Range Corresponding designationfrequency range Subcarrier Spacing FR1 410 MHz-7125 MHz 15, 30, 60kHz FR2 24250 MHz-52600 MHz 60, 120, 240 kHz

[0072] In the present disclosure, the term "cell" may refer to ageographic area to which one or more nodes provide a communicationsystem, or refer to radio resources. A "cell" as a geographic areamay be understood as coverage within which a node can provideservice using a carrier and a "cell" as radio resources (e.g.,time-frequency resources) is associated with bandwidth which is afrequency range configured by the carrier. The "cell" associatedwith the radio resources is defined by a combination of downlinkresources and uplink resources, for example, a combination of a DLcomponent carrier (CC) and a UL CC. The cell may be configured bydownlink resources only, or may be configured by downlink resourcesand uplink resources. Since DL coverage, which is a range withinwhich the node is capable of transmitting a valid signal, and ULcoverage, which is a range within which the node is capable ofreceiving the valid signal from the UE, depends upon a carriercarrying the signal, the coverage of the node may be associatedwith coverage of the "cell" of radio resources used by the node.Accordingly, the term "cell" may be used to represent servicecoverage of the node sometimes, radio resources at other times, ora range that signals using the radio resources can reach with validstrength at other times.

[0073] In CA, two or more CCs are aggregated. A UE maysimultaneously receive or transmit on one or multiple CCs dependingon its capabilities. CA is supported for both contiguous andnon-contiguous CCs. When CA is configured, the UE only has one RRCconnection with the network. At RRC connectionestablishment/re-establishment/handover, one serving cell providesthe NAS mobility information, and at RRC connectionre-establishment/handover, one serving cell provides the securityinput. This cell is referred to as the primary cell (PCell). ThePCell is a cell, operating on the primary frequency, in which theUE either performs the initial connection establishment procedureor initiates the connection re-establishment procedure. Dependingon UE capabilities, secondary cells (SCells) can be configured toform together with the PCell a set of serving cells. An SCell is acell providing additional radio resources on top of special cell(SpCell). The configured set of serving cells for a UE thereforealways consists of one PCell and one or more SCells. For dualconnectivity (DC) operation, the term SpCell refers to the PCell ofthe master cell group (MCG) or the primary SCell (PSCell) of thesecondary cell group (SCG). An SpCell supports PUCCH transmissionand contention-based random access, and is always activated. TheMCG is a group of serving cells associated with a master node,comprised of the SpCell (PCell) and optionally one or more SCells.The SCG is the subset of serving cells associated with a secondarynode, comprised of the PSCell and zero or more SCells, for a UEconfigured with DC. For a UE in RRC_CONNECTED not configured withCA/DC, there is only one serving cell comprised of the PCell. For aUE in RRC_CONNECTED configured with CA/DC, the term "serving cells"is used to denote the set of cells comprised of the SpCell(s) andall SCells. In DC, two MAC entities are configured in a UE: one forthe MCG and one for the SCG.

[0074] FIG. 5 shows a data flow example in the 3GPP NR system towhich implementations of the present disclosure can be applied.

[0075] Referring to FIG. 5, "RB" denotes a radio bearer, and "H"denotes a header. Radio bearers are categorized into two groups:DRBs for user plane data and SRBs for control plane data. The MACPDU is transmitted/received using radio resources through the PHYlayer to/from an external device. The MAC PDU arrives to the PHYlayer in the form of a transport block.

[0076] In the PHY layer, the uplink transport channels UL-SCH andRACH are mapped to their physical channels physical uplink sharedchannel (PUSCH) and physical random access channel (PRACH),respectively, and the downlink transport channels DL-SCH, BCH andPCH are mapped to physical downlink shared channel (PDSCH),physical broadcast channel (PBCH) and PDSCH, respectively. In thePHY layer, uplink control information (UCI) is mapped to physicaluplink control channel (PUCCH), and downlink control information(DCI) is mapped to physical downlink control channel (PDCCH). A MACPDU related to UL-SCH is transmitted by a UE via a PUSCH based onan UL grant, and a MAC PDU related to DL-SCH is transmitted by a BSvia a PDSCH based on a DL assignment.

[0077] FIG. 6 shows an example of a communication system to whichimplementations of the present disclosure can be applied.

[0078] The 5G usage scenarios shown in FIG. 6 are only exemplary,and the technical features of the present disclosure can be appliedto other 5G usage scenarios which are not shown in FIG. 6.

[0079] Three main requirement categories for 5G include (1) acategory of enhanced mobile broadband (eMBB), (2) a category ofmassive machine type communication (mMTC), and (3) a category ofultra-reliable and low latency communications (URLLC).

[0080] Partial use cases may require a plurality of categories foroptimization and other use cases may focus only upon one keyperformance indicator (KPI). 5G supports such various use casesusing a flexible and reliable method.

[0081] eMBB far surpasses basic mobile Internet access and coversabundant bidirectional work and media and entertainmentapplications in cloud and augmented reality. Data is one of 5G coremotive forces and, in a 5G era, a dedicated voice service may notbe provided for the first time. In 5G, it is expected that voicewill be simply processed as an application program using dataconnection provided by a communication system. Main causes forincreased traffic volume are due to an increase in the size ofcontent and an increase in the number of applications requiringhigh data transmission rate. A streaming service (of audio andvideo), conversational video, and mobile Internet access will bemore widely used as more devices are connected to the Internet.These many application programs require connectivity of an alwaysturned-on state in order to push real-time information and alarmfor users. Cloud storage and applications are rapidly increasing ina mobile communication platform and may be applied to both work andentertainment. The cloud storage is a special use case whichaccelerates growth of uplink data transmission rate. 5G is alsoused for remote work of cloud. When a tactile interface is used, 5Gdemands much lower end-to-end latency to maintain user goodexperience.

[0082] Entertainment, for example, cloud gaming and videostreaming, is another core element which increases demand formobile broadband capability. Entertainment is essential for asmartphone and a tablet in any place including high mobilityenvironments such as a train, a vehicle, and an airplane. Other usecases are augmented reality for entertainment and informationsearch. In this case, the augmented reality requires very lowlatency and instantaneous data volume.

[0083] In addition, one of the most expected 5G use cases relates afunction capable of smoothly connecting embedded sensors in allfields, i.e., mMTC. It is expected that the number of potentialInternet-of-things (IoT) devices will reach 204 hundred million upto the year of 2020. An industrial IoT is one of categories ofperforming a main role enabling a smart city, asset tracking, smartutility, agriculture, and security infrastructure through 5G.

[0084] URLLC includes a new service that will change industrythrough remote control of main infrastructure and anultra-reliable/available low-latency link such as a self-drivingvehicle. A level of reliability and latency is essential to controla smart grid, automatize industry, achieve robotics, and controland adjust a drone.

[0085] 5G is a means of providing streaming evaluated as a fewhundred megabits per second to gigabits per second and maycomplement fiber-to-the-home (FTTH) and cable-based broadband (orDOCSIS). Such fast speed is needed to deliver TV in resolution of4K or more (6K, 8K, and more), as well as virtual reality andaugmented reality. Virtual reality (VR) and augmented reality (AR)applications include almost immersive sports games.

[0086] A specific application program may require a special networkconfiguration. For example, for VR games, gaming companies need toincorporate a core server into an edge network server of a networkoperator in order to minimize latency.

[0087] Automotive is expected to be a new important motivated forcein 5G together with many use cases for mobile communication forvehicles. For example, entertainment for passengers requires highsimultaneous capacity and mobile broadband with high mobility. Thisis because future users continue to expect connection of highquality regardless of their locations and speeds. Another use caseof an automotive field is an AR dashboard. The AR dashboard causesa driver to identify an object in the dark in addition to an objectseen from a front window and displays a distance from the objectand a movement of the object by overlapping information talking tothe driver. In the future, a wireless module enables communicationbetween vehicles, information exchange between a vehicle andsupporting infrastructure, and information exchange between avehicle and other connected devices (e.g., devices accompanied by apedestrian). A safety system guides alternative courses of abehavior so that a driver may drive more safely drive, therebylowering the danger of an accident. The next stage will be aremotely controlled or self-driven vehicle. This requires very highreliability and very fast communication between differentself-driven vehicles and between a vehicle and infrastructure. Inthe future, a self-driven vehicle will perform all drivingactivities and a driver will focus only upon abnormal traffic thatthe vehicle cannot identify. Technical requirements of aself-driven vehicle demand ultra-low latency and ultra-highreliability so that traffic safety is increased to a level thatcannot be achieved by human being.

[0088] A smart city and a smart home/building mentioned as a smartsociety will be embedded in a high-density wireless sensor network.A distributed network of an intelligent sensor will identifyconditions for costs and energy-efficient maintenance of a city ora home.

[0089] Similar configurations may be performed for respectivehouseholds. All of temperature sensors, window and heatingcontrollers, burglar alarms, and home appliances are wirelesslyconnected. Many of these sensors are typically low in datatransmission rate, power, and cost. However, real-time HD video maybe demanded by a specific type of device to perform monitoring.

[0090] Consumption and distribution of energy including heat or gasis distributed at a higher level so that automated control of thedistribution sensor network is demanded. The smart grid collectsinformation and connects the sensors to each other using digitalinformation and communication technology so as to act according tothe collected information. Since this information may includebehaviors of a supply company and a consumer, the smart grid mayimprove distribution of fuels such as electricity by a methodhaving efficiency, reliability, economic feasibility, productionsustainability, and automation. The smart grid may also be regardedas another sensor network having low latency.

[0091] Mission critical application (e.g., e-health) is one of 5Guse scenarios. A health part contains many application programscapable of enjoying benefit of mobile communication. Acommunication system may support remote treatment that providesclinical treatment in a faraway place. Remote treatment may aid inreducing a barrier against distance and improve access to medicalservices that cannot be continuously available in a faraway ruralarea. Remote treatment is also used to perform important treatmentand save lives in an emergency situation. The wireless sensornetwork based on mobile communication may provide remote monitoringand sensors for parameters such as heart rate and bloodpressure.

[0092] Wireless and mobile communication gradually becomesimportant in the field of an industrial application. Wiring is highin installation and maintenance cost. Therefore, a possibility ofreplacing a cable with reconstructible wireless links is anattractive opportunity in many industrial fields. However, in orderto achieve this replacement, it is necessary for wirelessconnection to be established with latency, reliability, andcapacity similar to those of the cable and management of wirelessconnection needs to be simplified. Low latency and a very low errorprobability are new requirements when connection to 5G isneeded.

[0093] Logistics and freight tracking are important use cases formobile communication that enables inventory and package trackinganywhere using a location-based information system. The use casesof logistics and freight typically demand low data rate but requirelocation information with a wide range and reliability.

[0094] Referring to FIG. 6, the communication system 1 includeswireless devices 100a to 100f, base stations (BSs) 200, and anetwork 300. Although FIG. 6 illustrates a 5G network as an exampleof the network of the communication system 1, the implementationsof the present disclosure are not limited to the 5G system, and canbe applied to the future communication system beyond the 5Gsystem.

[0095] The BSs 200 and the network 300 may be implemented aswireless devices and a specific wireless device may operate as aBS/network node with respect to other wireless devices.

[0096] The wireless devices 100a to 100f represent devicesperforming communication using radio access technology (RAT) (e.g.,5G new RAT (NR)) or LTE) and may be referred to ascommunication/radio/5G devices. The wireless devices 100a to 100fmay include, without being limited to, a robot 100a, vehicles100b-1 and 100b-2, an extended reality (XR) device 100c, ahand-held device 100d, a home appliance 100e, an IoT device 100f,and an artificial intelligence (AI) device/server 400. For example,the vehicles may include a vehicle having a wireless communicationfunction, an autonomous driving vehicle, and a vehicle capable ofperforming communication between vehicles. The vehicles may includean unmanned aerial vehicle (UAV) (e.g., a drone). The XR device mayinclude an AR/VR/Mixed Reality (MR) device and may be implementedin the form of a head-mounted device (HMD), a head-up display (HUD)mounted in a vehicle, a television, a smartphone, a computer, awearable device, a home appliance device, a digital signage, avehicle, a robot, etc. The hand-held device may include asmartphone, a smartpad, a wearable device (e.g., a smartwatch or asmartglasses), and a computer (e.g., a notebook). The homeappliance may include a TV, a refrigerator, and a washing machine.The IoT device may include a sensor and a smartmeter.

[0097] In the present disclosure, the wireless devices 100a to 100fmay be called user equipments (UEs). A UE may include, for example,a cellular phone, a smartphone, a laptop computer, a digitalbroadcast terminal, a personal digital assistant (PDA), a portablemultimedia player (PMP), a navigation system, a slate personalcomputer (PC), a tablet PC, an ultrabook, a vehicle, a vehiclehaving an autonomous traveling function, a connected car, an UAV,an AI module, a robot, an AR device, a VR device, an MR device, ahologram device, a public safety device, an MTC device, an IoTdevice, a medical device, a FinTech device (or a financial device),a security device, a weather/environment device, a device relatedto a 5G service, or a device related to a fourth industrialrevolution field.

[0098] The UAV may be, for example, an aircraft aviated by awireless control signal without a human being onboard.

[0099] The VR device may include, for example, a device forimplementing an object or a background of the virtual world. The ARdevice may include, for example, a device implemented by connectingan object or a background of the virtual world to an object or abackground of the real world. The MR device may include, forexample, a device implemented by merging an object or a backgroundof the virtual world into an object or a background of the realworld. The hologram device may include, for example, a device forimplementing a stereoscopic image of 360 degrees by recording andreproducing stereoscopic information, using an interferencephenomenon of light generated when two laser lights calledholography meet.

[0100] The public safety device may include, for example, an imagerelay device or an image device that is wearable on the body of auser.

[0101] The MTC device and the IoT device may be, for example,devices that do not require direct human intervention ormanipulation. For example, the MTC device and the IoT device mayinclude smartmeters, vending machines, thermometers, smartbulbs,door locks, or various sensors.

[0102] The medical device may be, for example, a device used forthe purpose of diagnosing, treating, relieving, curing, orpreventing disease. For example, the medical device may be a deviceused for the purpose of diagnosing, treating, relieving, orcorrecting injury or impairment. For example, the medical devicemay be a device used for the purpose of inspecting, replacing, ormodifying a structure or a function. For example, the medicaldevice may be a device used for the purpose of adjusting pregnancy.For example, the medical device may include a device for treatment,a device for operation, a device for (in vitro) diagnosis, ahearing aid, or a device for procedure.

[0103] The security device may be, for example, a device installedto prevent a danger that may arise and to maintain safety. Forexample, the security device may be a camera, a closed-circuit TV(CCTV), a recorder, or a black box.

[0104] The FinTech device may be, for example, a device capable ofproviding a financial service such as mobile payment. For example,the FinTech device may include a payment device or a point of sales(POS) system.

[0105] The weather/environment device may include, for example, adevice for monitoring or predicting a weather/environment.

[0106] The wireless devices 100a to 100f may be connected to thenetwork 300 via the BSs 200. An AI technology may be applied to thewireless devices 100a to 100f and the wireless devices 100a to 100fmay be connected to the AI server 400 via the network 300. Thenetwork 300 may be configured using a 3G network, a 4G (e.g., LTE)network, a 5G (e.g., NR) network, and a beyond-5G network. Althoughthe wireless devices 100a to 100f may communicate with each otherthrough the BSs 200/network 300, the wireless devices 100a to 100fmay perform direct communication (e.g., sidelink communication)with each other without passing through the BSs 200/network 300.For example, the vehicles 100b-1 and 100b-2 may perform directcommunication (e.g., vehicle-to-vehicle (V2V)/vehicle-to-everything(V2X) communication). The IoT device (e.g., a sensor) may performdirect communication with other IoT devices (e.g., sensors) orother wireless devices 100a to 100f.

[0107] Wireless communication/connections 150a, 150b and 150c maybe established between the wireless devices 100a to 100f and/orbetween wireless device 100a to 100f and BS 200 and/or between BSs200. Herein, the wireless communication/connections may beestablished through various RATs (e.g., 5G NR) such asuplink/downlink communication 150a, sidelink communication (ordevice-to-device (D2D) communication) 150b, inter-base stationcommunication 150c (e.g., relay, integrated access and backhaul(IAB)), etc. The wireless devices 100a to 100f and the BSs 200/thewireless devices 100a to 100f may transmit/receive radio signalsto/from each other through the wireless communication/connections150a, 150b and 150c. For example, the wirelesscommunication/connections 150a, 150b and 150c may transmit/receivesignals through various physical channels. To this end, at least apart of various configuration information configuring processes,various signal processing processes (e.g., channelencoding/decoding, modulation/demodulation, and resourcemapping/de-mapping), and resource allocating processes, fortransmitting/receiving radio signals, may be performed based on thevarious proposals of the present disclosure.

[0108] FIG. 7 shows an example of wireless devices to whichimplementations of the present disclosure can be applied.

[0109] Referring to FIG. 7, a first wireless device 100 and asecond wireless device 200 may transmit/receive radio signalsto/from an external device through a variety of RATs (e.g., LTE andNR). In FIG. 7, {the first wireless device 100 and the secondwireless device 200} may correspond to at least one of {thewireless device 100a to 100f and the BS 200}, {the wireless device100a to 100f and the wireless device 100a to 100f} and/or {the BS200 and the BS 200} of FIG. 6.

[0110] The first wireless device 100 may include one or moreprocessors 102 and one or more memories 104 and additionallyfurther include one or more transceivers 106 and/or one or moreantennas 108. The processor(s) 102 may control the memory(s) 104and/or the transceiver(s) 106 and may be configured to implementthe descriptions, functions, procedures, suggestions, methodsand/or operational flowcharts described in the present disclosure.For example, the processor(s) 102 may process information withinthe memory(s) 104 to generate first information/signals and thentransmit radio signals including the first information/signalsthrough the transceiver(s) 106. The processor(s) 102 may receiveradio signals including second information/signals through thetransceiver(s) 106 and then store information obtained byprocessing the second information/signals in the memory(s) 104. Thememory(s) 104 may be connected to the processor(s) 102 and maystore a variety of information related to operations of theprocessor(s) 102. For example, the memory(s) 104 may store softwarecode including commands for performing a part or the entirety ofprocesses controlled by the processor(s) 102 or for performing thedescriptions, functions, procedures, suggestions, methods and/oroperational flowcharts described in the present disclosure. Herein,the processor(s) 102 and the memory(s) 104 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g.,LTE or NR). The transceiver(s) 106 may be connected to theprocessor(s) 102 and transmit and/or receive radio signals throughone or more antennas 108. Each of the transceiver(s) 106 mayinclude a transmitter and/or a receiver. The transceiver(s) 106 maybe interchangeably used with radio frequency (RF) unit(s). In thepresent disclosure, the first wireless device 100 may represent acommunication modem/circuit/chip.

[0111] The second wireless device 200 may include one or moreprocessors 202 and one or more memories 204 and additionallyfurther include one or more transceivers 206 and/or one or moreantennas 208. The processor(s) 202 may control the memory(s) 204and/or the transceiver(s) 206 and may be configured to implementthe descriptions, functions, procedures, suggestions, methodsand/or operational flowcharts described in the present disclosure.For example, the processor(s) 202 may process information withinthe memory(s) 204 to generate third information/signals and thentransmit radio signals including the third information/signalsthrough the transceiver(s) 206. The processor(s) 202 may receiveradio signals including fourth information/signals through thetransceiver(s) 106 and then store information obtained byprocessing the fourth information/signals in the memory(s) 204. Thememory(s) 204 may be connected to the processor(s) 202 and maystore a variety of information related to operations of theprocessor(s) 202. For example, the memory(s) 204 may store softwarecode including commands for performing a part or the entirety ofprocesses controlled by the processor(s) 202 or for performing thedescriptions, functions, procedures, suggestions, methods and/oroperational flowcharts described in the present disclosure. Herein,the processor(s) 202 and the memory(s) 204 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g.,LTE or NR). The transceiver(s) 206 may be connected to theprocessor(s) 202 and transmit and/or receive radio signals throughone or more antennas 208. Each of the transceiver(s) 206 mayinclude a transmitter and/or a receiver. The transceiver(s) 206 maybe interchangeably used with RF unit(s). In the present disclosure,the second wireless device 200 may represent a communicationmodem/circuit/chip.

[0112] Hereinafter, hardware elements of the wireless devices 100and 200 will be described more specifically. One or more protocollayers may be implemented by, without being limited to, one or moreprocessors 102 and 202. For example, the one or more processors 102and 202 may implement one or more layers (e.g., functional layerssuch as physical (PHY) layer, media access control (MAC) layer,radio link control (RLC) layer, packet data convergence protocol(PDCP) layer, radio resource control (RRC) layer, and service dataadaptation protocol (SDAP) layer). The one or more processors 102and 202 may generate one or more protocol data units (PDUs) and/orone or more service data unit (SDUs) according to the descriptions,functions, procedures, suggestions, methods and/or operationalflowcharts disclosed in the present disclosure. The one or moreprocessors 102 and 202 may generate messages, control information,data, or information according to the descriptions, functions,procedures, suggestions, methods and/or operational flowchartsdisclosed in the present disclosure. The one or more processors 102and 202 may generate signals (e.g., baseband signals) includingPDUs, SDUs, messages, control information, data, or informationaccording to the descriptions, functions, procedures, suggestions,methods and/or operational flowcharts disclosed in the presentdisclosure and provide the generated signals to the one or moretransceivers 106 and 206. The one or more processors 102 and 202may receive the signals (e.g., baseband signals) from the one ormore transceivers 106 and 206 and acquire the PDUs, SDUs, messages,control information, data, or information according to thedescriptions, functions, procedures, suggestions, methods and/oroperational flowcharts disclosed in the present disclosure.

[0113] The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers.The one or more processors 102 and 202 may be implemented byhardware, firmware, software, or a combination thereof. As anexample, one or more application specific integrated circuits(ASICs), one or more digital signal processors (DSPs), one or moredigital signal processing devices (DSPDs), one or more programmablelogic devices (PLDs), or one or more field programmable gate arrays(FPGAs) may be included in the one or more processors 102 and 202.descriptions, functions, procedures, suggestions, methods and/oroperational flowcharts disclosed in the present disclosure may beimplemented using firmware or software and the firmware or softwaremay be configured to include the modules, procedures, or functions.Firmware or software configured to perform the descriptions,functions, procedures, suggestions, methods and/or operationalflowcharts disclosed in the present disclosure may be included inthe one or more processors 102 and 202 or stored in the one or morememories 104 and 204 so as to be driven by the one or moreprocessors 102 and 202. The descriptions, functions, procedures,suggestions, methods and/or operational flowcharts disclosed in thepresent disclosure may be implemented using firmware or software inthe form of code, commands, and/or a set of commands.

[0114] The one or more memories 104 and 204 may be connected to theone or more processors 102 and 202 and store various types of data,signals, messages, information, programs, code, instructions,and/or commands. The one or more memories 104 and 204 may beconfigured by read-only memories (ROMs), random access memories(RAMs), electrically erasable programmable read-only memories(EPROMs), flash memories, hard drives, registers, cash memories,computer-readable storage media, and/or combinations thereof. Theone or more memories 104 and 204 may be located at the interiorand/or exterior of the one or more processors 102 and 202. The oneor more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 through various technologies such as wiredor wireless connection.

[0115] The one or more transceivers 106 and 206 may transmit userdata, control information, and/or radio signals/channels, mentionedin the descriptions, functions, procedures, suggestions, methodsand/or operational flowcharts disclosed in the present disclosure,to one or more other devices. The one or more transceivers 106 and206 may receive user data, control information, and/or radiosignals/channels, mentioned in the descriptions, functions,procedures, suggestions, methods and/or operational flowchartsdisclosed in the present disclosure, from one or more otherdevices. For example, the one or more transceivers 106 and 206 maybe connected to the one or more processors 102 and 202 and transmitand receive radio signals. For example, the one or more processors102 and 202 may perform control so that the one or moretransceivers 106 and 206 may transmit user data, controlinformation, or radio signals to one or more other devices. The oneor more processors 102 and 202 may perform control so that the oneor more transceivers 106 and 206 may receive user data, controlinformation, or radio signals from one or more other devices.

[0116] The one or more transceivers 106 and 206 may be connected tothe one or more antennas 108 and 208 and the one or moretransceivers 106 and 206 may be configured to transmit and receiveuser data, control information, and/or radio signals/channels,mentioned in the descriptions, functions, procedures, suggestions,methods and/or operational flowcharts disclosed in the presentdisclosure, through the one or more antennas 108 and 208. In thepresent disclosure, the one or more antennas may be a plurality ofphysical antennas or a plurality of logical antennas (e.g., antennaports).

[0117] The one or more transceivers 106 and 206 may convertreceived radio signals/channels, etc., from RF band signals intobaseband signals in order to process received user data, controlinformation, radio signals/channels, etc., using the one or moreprocessors 102 and 202. The one or more transceivers 106 and 206may convert the user data, control information, radiosignals/channels, etc., processed using the one or more processors102 and 202 from the base band signals into the RF band signals. Tothis end, the one or more transceivers 106 and 206 may include(analog) oscillators and/or filters. For example, the transceivers106 and 206 can up-convert OFDM baseband signals to a carrierfrequency by their (analog) oscillators and/or filters under thecontrol of the processors 102 and 202 and transmit the up-convertedOFDM signals at the carrier frequency. The transceivers 106 and 206may receive OFDM signals at a carrier frequency and down-convertthe OFDM signals into OFDM baseband signals by their (analog)oscillators and/or filters under the control of the transceivers102 and 202.

[0118] In the implementations of the present disclosure, a UE mayoperate as a transmitting device in uplink (UL) and as a receivingdevice in downlink (DL). In the implementations of the presentdisclosure, a BS may operate as a receiving device in UL and as atransmitting device in DL. Hereinafter, for convenience ofdescription, it is mainly assumed that the first wireless device100 acts as the UE, and the second wireless device 200 acts as theBS. For example, the processor(s) 102 connected to, mounted on orlaunched in the first wireless device 100 may be configured toperform the UE behavior according to an implementation of thepresent disclosure or control the transceiver(s) 106 to perform theUE behavior according to an implementation of the presentdisclosure. The processor(s) 202 connected to, mounted on orlaunched in the second wireless device 200 may be configured toperform the BS behavior according to an implementation of thepresent disclosure or control the transceiver(s) 206 to perform theBS behavior according to an implementation of the presentdisclosure.

[0119] In the present disclosure, a BS is also referred to as anode B (NB), an eNode B (eNB), or a gNB.

[0120] FIG. 8 shows an example of a wireless device to whichimplementations of the present disclosure can be applied.

[0121] The wireless device may be implemented in various formsaccording to a use-case/service (refer to FIG. 6).

[0122] Referring to FIG. 8, wireless devices 100 and 200 maycorrespond to the wireless devices 100 and 200 of FIG. 7 and may beconfigured by various elements, components, units/portions, and/ormodules. For example, each of the wireless devices 100 and 200 mayinclude a communication unit 110, a control unit 120, a memory unit130, and additional components 140. The communication unit 110 mayinclude a communication circuit 112 and transceiver(s) 114. Forexample, the communication circuit 112 may include the one or moreprocessors 102 and 202 of FIG. 7 and/or the one or more memories104 and 204 of FIG. 7. For example, the transceiver(s) 114 mayinclude the one or more transceivers 106 and 206 of FIG. 7 and/orthe one or more antennas 108 and 208 of FIG. 7. The control unit120 is electrically connected to the communication unit 110, thememory 130, and the additional components 140 and controls overalloperation of each of the wireless devices 100 and 200. For example,the control unit 120 may control an electric/mechanical operationof each of the wireless devices 100 and 200 based onprograms/code/commands/information stored in the memory unit 130.The control unit 120 may transmit the information stored in thememory unit 130 to the exterior (e.g., other communication devices)via the communication unit 110 through a wireless/wired interfaceor store, in the memory unit 130, information received through thewireless/wired interface from the exterior (e.g., othercommunication devices) via the communication unit 110.

[0123] The additional components 140 may be variously configuredaccording to types of the wireless devices 100 and 200. Forexample, the additional components 140 may include at least one ofa power unit/battery, input/output (I/O) unit (e.g., audio I/Oport, video I/O port), a driving unit, and a computing unit. Thewireless devices 100 and 200 may be implemented in the form of,without being limited to, the robot (100a of FIG. 6), the vehicles(100b-1 and 100b-2 of FIG. 6), the XR device (100c of FIG. 6), thehand-held device (100d of FIG. 6), the home appliance (100e of FIG.6), the IoT device (100f of FIG. 6), a digital broadcast terminal,a hologram device, a public safety device, an MTC device, amedicine device, a FinTech device (or a finance device), a securitydevice, a climate/environment device, the AI server/device (400 ofFIG. 6), the BSs (200 of FIG. 6), a network node, etc. The wirelessdevices 100 and 200 may be used in a mobile or fixed placeaccording to a use-example/service.

[0124] In FIG. 8, the entirety of the various elements, components,units/portions, and/or modules in the wireless devices 100 and 200may be connected to each other through a wired interface or atleast a part thereof may be wirelessly connected through thecommunication unit 110. For example, in each of the wirelessdevices 100 and 200, the control unit 120 and the communicationunit 110 may be connected by wire and the control unit 120 andfirst units (e.g., 130 and 140) may be wirelessly connected throughthe communication unit 110. Each element, component, unit/portion,and/or module within the wireless devices 100 and 200 may furtherinclude one or more elements. For example, the control unit 120 maybe configured by a set of one or more processors. As an example,the control unit 120 may be configured by a set of a communicationcontrol processor, an application processor (AP), an electroniccontrol unit (ECU), a graphical processing unit, and a memorycontrol processor. As another example, the memory 130 may beconfigured by a RAM, a DRAM, a ROM, a flash memory, a volatilememory, a non-volatile memory, and/or a combination thereof.

[0125] FIG. 9 shows another example of wireless devices to whichimplementations of the present disclosure can be applied.

[0126] Referring to FIG. 9, wireless devices 100 and 200 maycorrespond to the wireless devices 100 and 200 of FIG. 7 and may beconfigured by various elements, components, units/portions, and/ormodules.

[0127] The first wireless device 100 may include at least onetransceiver, such as a transceiver 106, and at least one processingchip, such as a processing chip 101. The processing chip 101 mayinclude at least one processor, such a processor 102, and at leastone memory, such as a memory 104. The memory 104 may be operablyconnectable to the processor 102. The memory 104 may store varioustypes of information and/or instructions. The memory 104 may storea software code 105 which implements instructions that, whenexecuted by the processor 102, perform the descriptions, functions,procedures, suggestions, methods and/or operational flowchartsdisclosed in the present disclosure. For example, the software code105 may implement instructions that, when executed by the processor102, perform the descriptions, functions, procedures, suggestions,methods and/or operational flowcharts disclosed in the presentdisclosure. For example, the software code 105 may control theprocessor 102 to perform one or more protocols. For example, thesoftware code 105 may control the processor 102 may perform one ormore layers of the radio interface protocol.

[0128] The second wireless device 200 may include at least onetransceiver, such as a transceiver 206, and at least one processingchip, such as a processing chip 201. The processing chip 201 mayinclude at least one processor, such a processor 202, and at leastone memory, such as a memory 204. The memory 204 may be operablyconnectable to the processor 202. The memory 204 may store varioustypes of information and/or instructions. The memory 204 may storea software code 205 which implements instructions that, whenexecuted by the processor 202, perform the descriptions, functions,procedures, suggestions, methods and/or operational flowchartsdisclosed in the present disclosure. For example, the software code205 may implement instructions that, when executed by the processor202, perform the descriptions, functions, procedures, suggestions,methods and/or operational flowcharts disclosed in the presentdisclosure. For example, the software code 205 may control theprocessor 202 to perform one or more protocols. For example, thesoftware code 205 may control the processor 202 may perform one ormore layers of the radio interface protocol.

[0129] FIG. 10 shows an example of UE to which implementations ofthe present disclosure can be applied.

[0130] Referring to FIG. 10, a UE 100 may correspond to the firstwireless device 100 of FIG. 7 and/or the first wireless device 100of FIG. 9.

[0131] A UE 100 includes a processor 102, a memory 104, atransceiver 106, one or more antennas 108, a power managementmodule 110, a battery 1112, a display 114, a keypad 116, asubscriber identification module (SIM) card 118, a speaker 120, anda microphone 122.

[0132] The processor 102 may be configured to implement thedescriptions, functions, procedures, suggestions, methods and/oroperational flowcharts disclosed in the present disclosure. Theprocessor 102 may be configured to control one or more othercomponents of the UE 100 to implement the descriptions, functions,procedures, suggestions, methods and/or operational flowchartsdisclosed in the present disclosure. Layers of the radio interfaceprotocol may be implemented in the processor 102. The processor 102may include ASIC, other chipset, logic circuit and/or dataprocessing device. The processor 102 may be an applicationprocessor. The processor 102 may include at least one of a digitalsignal processor (DSP), a central processing unit (CPU), a graphicsprocessing unit (GPU), a modem (modulator and demodulator). Anexample of the processor 102 may be found in SNAPDRAGON.TM. seriesof processors made by Qualcomm, EXYNOS series of processors made bySamsung.RTM., A series of processors made by Apple.RTM., HELLO.TM.series of processors made by MediaTek.RTM., ATOM.TM. series ofprocessors made by Intel.RTM. or a corresponding next generationprocessor.

[0133] The memory 104 is operatively coupled with the processor 102and stores a variety of information to operate the processor 102.The memory 104 may include ROM, RAM, flash memory, memory card,storage medium and/or other storage device. When the embodimentsare implemented in software, the techniques described herein can beimplemented with modules (e.g., procedures, functions, etc.) thatperform the descriptions, functions, procedures, suggestions,methods and/or operational flowcharts disclosed in the presentdisclosure. The modules can be stored in the memory 104 andexecuted by the processor 102. The memory 104 can be implementedwithin the processor 102 or external to the processor 102 in whichcase those can be communicatively coupled to the processor 102 viavarious means as is known in the art.

[0134] The transceiver 106 is operatively coupled with theprocessor 102, and transmits and/or receives a radio signal. Thetransceiver 106 includes a transmitter and a receiver. Thetransceiver 106 may include baseband circuitry to process radiofrequency signals. The transceiver 106 controls the one or moreantennas 108 to transmit and/or receive a radio signal.

[0135] The power management module 110 manages power for theprocessor 102 and/or the transceiver 106. The battery 112 suppliespower to the power management module 110.

[0136] The display 114 outputs results processed by the processor102. The keypad 116 receives inputs to be used by the processor102. The keypad 16 may be shown on the display 114.

[0137] The SIM card 118 is an integrated circuit that is intendedto securely store the international mobile subscriber identity(IMSI) number and its related key, which are used to identify andauthenticate subscribers on mobile telephony devices (such asmobile phones and computers). It is also possible to store contactinformation on many SIM cards.

[0138] The speaker 120 outputs sound-related results processed bythe processor 102. The microphone 122 receives sound-related inputsto be used by the processor 102.

[0139] V2X communication in 5G NR is described. Sections 5.2 and5.6 of 3GPP TS 23.287 V0.3.0 can be referred.

[0140] For V2X communication, two types of PC5 reference pointsexist: the LTE based PC5 reference point, and the NR based PC5reference point. A UE may use either type of PC5 or both for V2Xcommunication depending on the services the UE supports. The V2Xcommunication over PC5 reference point supports roaming andinter-public land mobile network (PLMN) operations. V2Xcommunication over PC5 reference point is supported when UE is"served by NR or E-UTRA" or when the UE is "not served by NR orE-UTRA".

[0141] A UE is authorized to transmit and receive V2X messages whenit has valid authorization and configuration.

[0142] The V2X communication over PC5 reference point has thefollowing characteristics: [0143] V2X communication over LTE basedPC5 reference point is connectionless, i.e., broadcast mode ataccess stratum (AS) layer, and there is no signaling over PC5 forconnection establishment. [0144] V2X communication over NR basedPC5 reference point supports broadcast mode, groupcast mode, andunicast mode at AS layer. The UE will indicate the mode ofcommunication for a V2X message to the AS layer. Signaling overcontrol plane over PC5 reference point for unicast modecommunication management is supported. [0145] V2X servicescommunication support between UEs over PC5 user plane. [0146] V2Xmessages are exchanged between UEs over PC5 user plane. Bothinternet protocol (IP) based and non-IP based V2X messages aresupported over PC5 reference point. For IP based V2X messages, onlyIP version 6 (IPv6) is used. IP version 4 (IPv4) is notsupported.

[0147] The identifiers used in the V2X communication over PC5reference point are described below in detail. UE decides on thetype of PC5 reference point and Tx Profile to use for thetransmission of a particular packet based on the configuration.

[0148] If the UE has an active emergency PDU session, thecommunication over the emergency PDU session shall be prioritizedover V2X communication over PC5 reference point.

[0149] Broadcast mode of communication is supported over both LTEbased PC5 reference point and NR based PC5 reference point.Therefore, when broadcast mode is selected for transmission overPC5 reference point, PC5 RAT selection needs to be performed basedon configuration.

[0150] For LTE based PC5 reference point, broadcast mode is theonly supported communication mode.

[0151] For NR based PC5 reference point, the broadcast mode alsosupports enhanced QoS handling.

[0152] Groupcast mode of communication is only supported over NRbased PC5 reference point.

[0153] Unicast mode of communication is only supported over NRbased PC5 reference point. When application layer initiates a V2Xservice which requires PC5 unicast communication, the UEestablishes a PC5 unicast link with the corresponding UE.

[0154] After successful PC5 unicast link establishment, UE A and UEB use a same pair of Layer-2 IDs for subsequent PC5-S signalingmessage exchange and V2X service data transmission. V2X layer ofthe transmitting UE indicates to AS layer whether the message isfor PC5-S signaling message (i.e., Direct Communication Accept,Link Layer Identifier Update Request/Response, DisconnectRequest/Response) or service data transmission when it sendsmessage over the established PC5 link. V2X layer of receiving UEhandles message if it is PC5-S signaling message whilst the V2Xlayer of receiving UE forwards the message to the upper layer if itis application data message.

[0155] The unicast mode supports per-flow QoS model. During theunicast link establishment, each UEs self-assign PC5 linkidentifier and associate the PC5 link identifier with the unicastlink profile for the established unicast link. The PC5 linkidentifier is a unique value within the UE. The unicast linkprofile identified by PC5 link identifier includes applicationlayer identifier and Layer-2 ID of UE A, application layeridentifier and Layer-2 ID of UE B and a set of PC5 QoS flowidentifier(s) (PFI(s)). Each PFI is associated with QoS parameters(i.e., PC5 QoS indicator (PQI) and optionally range). The PC5 linkidentifier and PFI(s) are unchanged values for the establishedunicast link regardless of the change of application layeridentifier and Layer-2 ID. The UE uses PFI to indicate the PC5 QoSflow to AS layer, therefore AS layer identifies the correspondingPC5 QoS flow even if the source and/or destination Layer-2 IDs arechanged due to, e.g., privacy support. The UE uses PC5 linkidentifier to indicate the PC5 unicast link to V2X applicationlayer, therefore V2X application layer identifies the correspondingPC5 unicast link even if there are more than one unicast linkassociated with one service type (e.g., the UE establishes multipleunicast links with multiple UEs for a same service type).

[0156] Identifiers for V2X communication is described.

[0157] Each UE has one or more Layer-2 IDs for V2X communicationover PC5 reference point, consisting of: [0158] Source Layer-2ID(s); and [0159] Destination Layer-2 ID(s).

[0160] Source and destination Layer-2 IDs are included in layer-2frames sent on the layer-2 link of the PC5 reference pointidentifying the layer-2 source and destination of these frames.Source Layer-2 IDs are always self-assigned by the UE originatingthe corresponding layer-2 frames.

[0161] The selection of the source and destination Layer-2 ID(s) bya UE depends on the communication mode of V2X communication overPC5 reference point for this layer-2 link, as described below indetail. The source Layer-2 IDs may differ between differentcommunication modes.

[0162] When IP-based V2X communication is supported, the UEconfigures a link local IPv6 address to be used as the source IPaddress. The UE may use this IP address for V2X communication overPC5 reference point without sending Neighbor Solicitation andNeighbor Advertisem*nt message for Duplicate Address Detection.

[0163] If the UE has an active V2X application that requiresprivacy support in the current geographical area, as identified byconfiguration, in order to ensure that a source UE (e.g., vehicle)cannot be tracked or identified by any other UEs (e.g., vehicles)beyond a certain short time-period required by the application, thesource Layer-2 ID shall be changed over time and shall berandomized. For IP-based V2X communication over PC5 referencepoint, the source IP address shall also be changed over time andshall be randomized. The change of the identifiers of a source UEmust be synchronized across layers used for PC5, e.g., when theapplication layer identifier changes, the source Layer-2 ID and thesource IP address need to be changed.

[0164] For broadcast mode of V2X communication over PC5 referencepoint, the UE is configured with the destination Layer-2 ID(s) tobe used for V2X services. The destination Layer-2 ID for a V2Xcommunication is selected based on the configuration.

[0165] The UE self-selects a source Layer-2 ID. The UE may usedifferent source Layer-2 IDs for different types of PC5 referencepoints, i.e., LTE based PC5 and NR based PC5.

[0166] For groupcast mode of V2X communication over PC5 referencepoint, the V2X application layer may provide group identifierinformation. When the group identifier information is provided bythe V2X application layer, the UE converts the provided groupidentifier into a destination Layer-2 ID. When the group identifierinformation is not provided by the V2X application layer, the UEdetermines the destination Layer-2 ID based on configuration of themapping between service type (e.g., PSID/ITS-AID) and Layer-2ID.

[0167] The UE self-selects a source Layer-2 ID.

[0168] For unicast mode of V2X communication over PC5 referencepoint, the destination Layer-2 ID used depends on the communicationpeer, which is discovered during the establishment of the unicastlink. The initial signaling for the establishment of the unicastlink may use a default destination Layer-2 ID associated with theservice type (e.g., PSID/ITS-AID) configured for unicast linkestablishment. During the unicast link establishment procedure,Layer-2 IDs are exchanged, and should be used for futurecommunication between the two UEs.

[0169] The UE needs to maintain a mapping between the applicationlayer identifiers and the source Layer-2 IDs used for the unicastlinks, as the V2X application layer does not use the Layer-2 IDs.This allows the change of source Layer-2 ID without interruptingthe V2X applications.

[0170] When application layer identifiers changes, the sourceLayer-2 ID(s) of the unicast link(s) shall be changed if thelink(s) was used for V2X communication with the changed applicationlayer identifiers.

[0171] A UE may establish multiple unicast links with a peer UE anduse the same or different source Layer-2 IDs for these unicastlinks.

[0172] FIGS. 11 and 12 show an example of PC5 protocol stacks towhich implementations of the present disclosure can be applied.

[0173] FIG. 11 illustrates an example of a PC5 control plane(PC5-C) protocol stack between UEs. The AS protocol stack for thecontrol plane in the PC5 interface consists of at least RRC, PDCP,RLC and MAC sublayers, and the physical layer.

[0174] FIG. 12 illustrates an example of a PC5 user plane (PC5-U)protocol stack between UEs. The AS protocol stack for user plane inthe PC5 interface consists of at least PDCP, RLC and MAC sublayers,and the physical layer.

[0175] Radio link failure related actions are described. Section5.3.10 of 3GPP TS 38.331 V15.5.0 can be referred.

[0176] For detection of physical layer problems in RRC_CONNECTED,the UE shall:

[0177] 1> upon receiving N310 consecutive "out-of-sync"indications for the SpCell from lower layers while neither T300,T301, T304, T311 nor T319 are running:

[0178] 2> start timer T310 for the corresponding SpCell.

[0179] For recovery of physical layer problems, upon receiving N311consecutive "in-sync" indications for the SpCell from lower layerswhile T310 is running, the UE shall:

[0180] 1> stop timer T310 for the corresponding SpCell.

[0181] The UE maintains the RRC connection without explicitsignalling, i.e., the UE maintains the entire radio resourceconfiguration.

[0182] Periods in time where neither "in-sync" nor "out-of-sync" isreported by L1 do not affect the evaluation of the number ofconsecutive "in-sync" or "out-of-sync" indications.

[0183] For detection of radio link failure, the UE shall:

[0184] 1> upon T310 expiry in PCell; or

[0185] 1> upon random access problem indication from MCG MACwhile neither T300, T301, T304, T311 nor T319 are running; or

[0186] 1> upon indication from MCG RLC that the maximum numberof retransmissions has been reached:

[0187] 2> if the indication is from MCG RLC and CA duplicationis configured and activated, and for the corresponding logicalchannel allowedServingCells only includes SCell(s):

[0188] 3> initiate the failure information procedure to reportRLC failure.

[0189] 2> else:

[0190] 3> consider radio link failure to be detected for theMCG, i.e., RLF;

[0191] 3> if AS security has not been activated:

[0192] 4> perform the actions upon going to RRC_IDLE, withrelease cause `other`;

[0193] 3> else if AS security has been activated but SRB2 and atleast one DRB have not been setup:

[0194] 4> perform the actions upon going to RRC_IDLE, withrelease cause `RRC connection failure`;

[0195] 3> else:

[0196] 4> initiate the connection re-establishmentprocedure.

[0197] The UE shall:

[0198] 1> upon T310 expiry in PSCell; or

[0199] 1> upon random access problem indication from SCG MAC;or

[0200] 1> upon indication from SCG RLC that the maximum numberof retransmissions has been reached:

[0201] 2> if the indication is from SCG RLC and CA duplicationis configured and activated; and for the corresponding logicalchannel allowedServingCells only includes SCell(s):

[0202] 3> initiate the failure information procedure to reportRLC failure.

[0203] 2> else:

[0204] 3> consider radio link failure to be detected for theSCG, i.e., SCG RLF;

[0205] 3> initiate the SCG failure information procedure toreport SCG radio link failure.

[0206] As mentioned above, for radio link monitoring (RLM) on Uuinterface, a UE measures signals transmitted by the base station.Then, a lower layer (e.g., physical layer) of a UE determinesin-sync or out-of-sync and periodically indicates in-sync (IS) orout-of-sync (00S) to an upper layer (e.g., RRC layer) of the UE.Based on the number of out-of-sync indications, the upper layer ofthe UE determines whether the radio link failure occurs or not.

[0207] For NR V2X sidelink communication, a UE (e.g., RX UE) may beconnected to another UE (e.g., TX UE) via a PC5-RRC connection andreceive sidelink data from the TX UE. The RX UE may measure thesidelink control information (SCI) transmitted by the TX UE for thePC5-RRC connection and then determine in-sync and/or out-of-syncbased on the received SCI. However, the TX UE may transmit the SCIonly when SL data transmission occurs. Therefore, the RX UE may notreceive the SCI sometimes. In this case, it is not clear how the RXUE can determine in-sync or out-of-sync based on the SCI.

[0208] In addition to the purpose of RLM, for the purpose ofsidelink management, there may be need to transmit SCI without SLdata.

[0209] For example, SCI without SL data needs to be transmittedwithin appropriate time period for sidelink management. Forexample, SCI transmission should be transmitted within a latencybound.

[0210] The following drawings are created to explain specificembodiments of the present disclosure. The names of the specificdevices or the names of the specific signals/messages/fields shownin the drawings are provided by way of example, and thus thetechnical features of the present disclosure are not limited to thespecific names used in the following drawings.

[0211] In some implementations, the method in perspective of thewireless device described below may be performed by first wirelessdevice 100 shown in FIG. 7, the wireless device 100 shown in FIG.8, the first wireless device 100 shown in FIG. 9 and/or the UE 100shown in FIG. 10.

[0212] In some implementations, the method in perspective of thewireless device described below may be performed by control of theprocessor 102 included in the first wireless device 100 shown inFIG. 7, by control of the communication unit 110 and/or the controlunit 120 included in the wireless device 100 shown in FIG. 8, bycontrol of the processor 102 included in the first wireless device100 shown in FIG. 9 and/or by control of the processor 102 includedin the UE 100 shown in FIG. 10.

[0213] FIG. 13 shows an example of a method for a wireless deviceto which implementations of the present disclosure can beapplied.

[0214] In step S1300, the wireless device determines that SLresource has not been reserved within a time period related totransmission of SCI. In step S1310, the wireless device triggers SLresource reservation for transmission of the SCI. For example,wireless device triggers SL resource reservation based on that SLresource has not been reserved within a time period related totransmission of SCI.

[0215] In some implementations, the time period may be a SCIperiod.

[0216] In some implementations, the SL resource may not beenreserved within the period after latest transmission of theSCI.

[0217] In some implementations, the wireless device may transmitthe SCI by using the SL resource reserved based on the SL resourcereservation. The SL resource may be reserved on a resource poolwith a specific priority.

[0218] In some implementations, the SCI may indicates the specificpriority. The specific priority may be a priority configured by anetwork and/or a pre-configuration stored in the first wirelessdevice. The specific priority may be a highest priority or a lowestpriority. The specific priority may indicate transmission of theSCI without transmitting sidelink data.

[0219] In some implementations, the SCI may indicate no sidelinkshared channel (SL-SCH) transmission.

[0220] In some implementations, the SCI may indicate a specificidentifier (ID) which indicate no SL-SCH transmission. The specificID may include at least one of a source ID, a destination ID and/oran ID associated with a link between the first wireless device andthe second wireless device.

[0221] In some implementations, the wireless device may be incommunication with at least one of a mobile device, a network,and/or autonomous vehicles other than the wireless device.

[0222] In some implementations, the SCI transmission describedabove may correspond to SL channel state information (SCI)reporting.

[0223] FIG. 14 shows an example of a method for performing sidelinkcommunication for a UE to which implementations of the presentdisclosure can be applied.

[0224] In some implementations, the first UE, e.g., TX UE, mayestablish a connection with network (e.g., gNB). The first UE mayperform initial access towards the cell. The first UE and the cellmay perform random access procedure. The first UE may establishand/or resume a connection with the network and entersRRC_CONNECTED. The first UE may perform AS security activation uponreceiving security mode command from the network. The first UE mayconfigure radio bearers and radio configuration upon receiving RRCreconfiguration and/or resumes radio bearers and radioconfiguration upon receiving RRC resume.

[0225] In step S1400, the first UE may be configured with a SCIperiod for management of the direct link by the network and/orpre-configuration.

[0226] In step S1402, the first UE and the second UE, e.g., RX UE,establish PC5-RRC connection.

[0227] In step S1404, the first UE establishes a direct link withthe second UE for sidelink unicast transmission and/or for sidelinkgroupcast transmission.

[0228] In some implementations, one or more resource pools may beconfigured for sidelink transmissions on the direct link. Theresource pools may be configured on the same BWP of the samecarrier, different BWPs of the same carrier, and/or differentcarriers. The resource pools may be associated with the directlink, e.g., with a pair of a source ID and destination ID, and/or alink ID.

[0229] In step S1406, the first UE may inform the second UE aboutconfiguration of the SCI period.

[0230] In step S1408, the second UE starts PC5 RLM.

[0231] In step S1410, the first UE transmits SCI to the second UE.The SCI may indicate link ID.

[0232] In some implementations, the SCI may indicate a certain SCIperiod, e.g., the next SCI period. During the indicated SCI period,if data is not available for STCH associated with one of theresource pools, the first UE may not transmit a SCI.

[0233] Alternatively, when the first UE transmits SCI, the SCI mayindicate time duration which starts from the SCI transmission ortransmission of a MAC PDU indicated by the SCI. During the timeduration, if data is not available for STCH associated with one ofthe resource pools, the first UE may not transmit a SCI.

[0234] In step S1412, the first UE transmits a SL-SCH to the secondUE. The SL-SCH may be scheduled by the SCI.

[0235] In some implementations, whenever data and a resource areavailable for transmission, the first UE may transmit SCI and a MACPDU on the SL-SCH to the second UE via at least one resource pool.The first UE may transmit multiple SCIs and multiple MAC PDUs tothe second UE on the SL-SCH. Each MAC PDU may be indicated andscheduled based on the SCI.

[0236] In some implementations, if data is available for STCHassociated with one of the resource pools, and if a resource hasbeen reserved on one of the resource pools and an interval betweenthe resource and the latest SCI transmission is within the SCIperiod, the first UE may transmit the SCI and a MAC PDU on theSL-SCH based on the SCI by using the resource.

[0237] In some implementations, the HARQ entity of the first UE maytrigger the transmission of the SCI and a MAC PDU for a HARQprocess.

[0238] In some implementations, different SCIs transmitted to thesecond UE may indicate different IDs of the same ID type. Forexample, different SCIs may indicate different source layer-2 IDs,different destination layer-2 IDs, and/or different link IDs. But,different IDs may be associated with the direct link between thefirst UE and the second UE.

[0239] In some implementations, the ID may be a particular IDindicating PC5 RLM or no SCI transmission.

[0240] In some implementations, upon transmission of a PC5-RRCrequest message to the second UE, upon reception of a PC5-RRCresponse message from the second UE, upon transmission of the firstSCI to the second UE and/or upon the new transmission or the lastretransmission of the first MAC PDU for the direct link to thesecond UE, the first UE may start a timer for a SCI period. Uponexpiry of the timer, the first UE may restart a timer for a nextSCI period. In FIG. 14, the timer starts upon transmission of thefirst SCI to the second UE.

[0241] In some implementations, if the second UE receives SCIindicating at least one ID in step S1410, and the ID is associatedwith the direct link, the second UE may consider the SCItransmission for management of the direct link.

[0242] In some implementations, upon receiving the SCI, the secondUE may not transmit HARQ feedback to the first UE.

[0243] In some implementations, upon reception of a PC5-RRC requestmessage from the first UE, upon transmission of a PC5-RRC responsemessage to the first UE, upon reception of the first SCI from thefirst UE and/or upon reception of the new transmission or the lastretransmission of the first MAC PDU for the direct link from thefirst UE, the second UE may start a timer for a SCI period. Uponexpiry of the timer, the first UE may restart a timer for a nextSCI period.

[0244] In step S1414, the second UE determines either in-syncand/or out-of-sync based on each of the SCIs and provides eachindication to an upper layer of the second UE for every SCI period,e.g., whenever the timer expires.

[0245] In some implementations, if the second UE does not receiveany SCI from the first UE for a SCI period, e.g., whenever thetimer expires, the second UE may determine out-of-sync for the SCIperiod. Alternatively, in this case the second UE may determinein-sync for the SCI period.

[0246] In some implementations, if the second UE receives a SCIwhich indicates a certain SCI period, e.g., the next SCI period,and if any SCI is not received for the indicated SCI period, thesecond UE may determine in-sync for the indicated SCI period.

[0247] Alternatively, if the second UE receives a SCI whichindicates time duration period, the second UE may start the timeduration from the SCI transmission or transmission of a MAC PDUindicated by the SCI. During the time duration, if any SCI is notreceived for time duration, the second UE may determine in-sync forthe time duration.

[0248] In some implementations, the upper layer (e.g., RRC layer)of the second UE may determine whether link failure occurs or notfor the direct link if a certain number of out-of-sync indicationsoccur consecutively.

[0249] In some implementations, the second UE may indicate thenumber of out-of-sync indications to the first UE and/or thenetwork.

[0250] In some implementations, upon link failure detection, thesecond UE may consider the direct link is released.

[0251] In step S1416, the data is available for link ID in thefirst UE.

[0252] In step S1418, the first UE transmits SCI to the second UE.The SCI may indicate the link ID.

[0253] In step S1420, the first UE transmits a SL-SCH to the secondUE. The SL-SCH may be scheduled by the SCI.

[0254] In step S1422, the second UE determines either in-syncand/or out-of-sync based on each of the SCIs and provides eachindication to an upper layer of the second UE for every SCI period,e.g., whenever the timer expires.

[0255] In step S1424, data is not available for link ID in thefirst UE.

[0256] In step S1426, if data is not available for any STCHassociated with one of the resource pools, and if a resource hasbeen not reserved on any of the resource pools within the SCIperiod after the latest SCI transmission, the first UE triggers SLresource reservation procedure for a SCI transmission in which theUE reserves at least one resource on one of the resource poolsassociated with the direct link by associating a particularpriority to this SCI transmission.

[0257] In step S1428, the first UE transmits SCI to the second UE.The SCI may indicate the link ID and/or no data transmission.

[0258] In some implementations, the particular priority may be apriority configured by the network and/or pre-configuration. Theparticular priority may be a certain fixed priority for this typeof SCI transmission (i.e., for PC5 RLM or for no SL-SCHtransmission). The particular priority may be the highest priorityand/or the lowest priority. The SCI may indicate the particularpriority to the RX UE.

[0259] In some implementations, the HARQ entity of the first UE maytrigger transmission of the SCI without triggering SL-SCHtransmission.

[0260] In some implementations, the SCI may indicate PC5 RLM, noSL-SCH transmission and/or no HARQ feedback.

[0261] In some implementations, the SCI may indicate a particularID which is used to indicate PC5 RLM, no SL-SCH transmission and/orno HARQ feedback. The particular ID may be one of the IDsassociated with the direct link, e.g., the source layer-2 ID, thedestination layer-2 ID and/or the link ID.

[0262] In some implementations, after the resource has beenreserved for this SCI transmission, if data becomes available forSTCH associated with one of the resource pools before this SCItransmission, the UE may reserve a new resource on any of theresource pools within the SCI period after the latest SCItransmission for a certain MAC PDU. If the new resource is reservedfor a certain MAC PDU, the UE may cancel the previously reservedresource for this SCI transmission and/or stops this SCItransmission.

[0263] In some implementations, if data is not available for anySTCH associated with one of the resource pools, and if a resourcehas been reserved on at least one of the resource pools within theSCI period after the latest SCI transmission, the first UE maytransmit the SCI by using the resource and may skip SL-SCHtransmission indicated by the SCI.

[0264] In some implementations, the HARQ entity of the first UE maytrigger transmission of the SCI without triggering SL-SCHtransmission.

[0265] In some implementations, the SCI may indicate PC5 RLM, noSL-SCH transmission and/or no HARQ feedback.

[0266] In some implementations, the SCI may indicate a particularID which is used to indicate PC5 RLM, no SL-SCH transmission and/orno HARQ feedback. The particular ID may be one of the IDsassociated with the direct link, e.g., the source layer-2 ID, thedestination layer-2 ID, and/or the link ID.

[0267] Alternatively, if data is not available for any STCHassociated with one of the resource pools, and if a resource isreserved on one of the resource pools and an interval between theresource and the latest SCI transmission is within the SCI period,the first UE may transmit the SCI and SL-SCH transmission by usingthe resource.

[0268] In some implementations, the HARQ entity of the first UE maycreate a MAC PDU having no MAC SDU and trigger transmission of theMAC PDU on the SL-SCH based on the SCI. The MAC PDU may include aMAC header indicating one of the IDs, PC5 RLM and/or no SL datawithout MAC SDU. Or, the MAC PDU may include a MAC headerindicating a MAC control element (CE) indicating one of the IDs,PC5 RLM and/or no SL data.

[0269] In some implementations, the MAC header may include theparticular logical channel ID (LCID) value allocated for no SL dataor SCI only transmission.

[0270] In some implementations, the MAC header may include theparticular source (SRC) value and the particular destination (DST)value allocated for no SL data or SCI only transmission.

[0271] In step S1430, the second UE determines either in-syncand/or out-of-sync based on each of the SCIs and provides eachindication to an upper layer of the second UE for every SCI period,e.g., whenever the timer expires.

[0272] In the present disclosure, SCI may be replaced by areference signal and/or any type of a physical channel for PC5RLM.

[0273] The present disclosure can have various advantageouseffects.

[0274] For example, a UE can transmit control information (e.g.,SCI) for sidelink management within appropriate time period.

[0275] For example, a UE can reserve a resource and transmitcontrol information (e.g., SCI) for a direct link with other UE, inparticular when the UE has no data to be transmitted to the otherUE.

[0276] For example, the system can reliably manage a direct linkbetween two UEs performing sidelink communication.

[0277] Advantageous effects which can be obtained through specificembodiments of the present disclosure are not limited to theadvantageous effects listed above. For example, there may be avariety of technical effects that a person having ordinary skill inthe related art can understand and/or derive from the presentdisclosure. Accordingly, the specific effects of the presentdisclosure are not limited to those explicitly described herein,but may include various effects that may be understood or derivedfrom the technical features of the present disclosure.

[0278] Claims in the present disclosure can be combined in avarious way. For instance, technical features in method claims ofthe present disclosure can be combined to be implemented orperformed in an apparatus, and technical features in apparatusclaims can be combined to be implemented or performed in a method.Further, technical features in method claim(s) and apparatusclaim(s) can be combined to be implemented or performed in anapparatus. Further, technical features in method claim(s) andapparatus claim(s) can be combined to be implemented or performedin a method. Other implementations are within the scope of thefollowing claims.

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