Patent Description:
Sidelink (SL) communication is a communication scheme in which a direct link is established between User Equipments (UEs) and the UEs exchange voice and data directly with each other without intervention of an evolved Node B (eNB). SL communication is under consideration as a solution to the overhead of an eNB caused by rapidly increasing data traffic.

Vehicle-to-everything (V2X) refers to a communication technology through which a vehicle exchanges information with another vehicle, a pedestrian, an object having an infrastructure (or infra) established therein, and so on. The V2X may be divided into <NUM> types, such as vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). The V2X communication may be provided via a PC5 interface and/or Uu interface.

Regarding V2X communication, a scheme of providing a safety service, based on a V2X message such as Basic Safety Message (BSM), Cooperative Awareness Message (CAM), and Decentralized Environmental Notification Message (DENM) is focused in the discussion on the RAT used before the NR. The V2X message may include position information, dynamic information, attribute information, or the like. For example, a UE may transmit a periodic message type CAM and/or an event triggered message type DENM to another UE.

For example, the CAM may include dynamic state information of the vehicle such as direction and speed, static data of the vehicle such as a size, and basic vehicle information such as an exterior illumination state, route details, or the like. For example, the UE may broadcast the CAM, and latency of the CAM may be less than <NUM>. For example, the UE may generate the DENM and transmit it to another UE in an unexpected situation such as a vehicle breakdown, accident, or the like. For example, all vehicles within a transmission range of the UE may receive the CAM and/or the DENM. In this case, the DENM may have a higher priority than the CAM.

Thereafter, regarding V2X communication, various V2X scenarios are proposed in NR. For example, the various V2X scenarios may include vehicle platooning, advanced driving, extended sensors, remote driving, or the like.

For example, based on the vehicle platooning, vehicles may move together by dynamically forming a group. For example, in order to perform platoon operations based on the vehicle platooning, the vehicles belonging to the group may receive periodic data from a leading vehicle. For example, the vehicles belonging to the group may decrease or increase an interval between the vehicles by using the periodic data.

For example, based on the advanced driving, the vehicle may be semi-automated or fully automated. For example, each vehicle may adjust trajectories or maneuvers, based on data obtained from a local sensor of a proximity vehicle and/or a proximity logical entity. In addition, for example, each vehicle may share driving intention with proximity vehicles.

For example, based on the extended sensors, raw data, processed data, or live video data obtained through the local sensors may be exchanged between a vehicle, a logical entity, a UE of pedestrians, and/or a V2X application server. Therefore, for example, the vehicle may recognize a more improved environment than an environment in which a self-sensor is used for detection.

For example, based on the remote driving, for a person who cannot drive or a remote vehicle in a dangerous environment, a remote driver or a V2X application may operate or control the remote vehicle. For example, if a route is predictable such as public transportation, cloud computing based driving may be used for the operation or control of the remote vehicle. In addition, for example, an access for a cloud-based back-end service platform may be considered for the remote driving.

Meanwhile, a scheme of specifying service requirements for various V2X scenarios such as vehicle platooning, advanced driving, extended sensors, remote driving, or the like is discussed in NR-based V2X communication.

The document ("<NPL>) outlines triggering to initiate/cancel CSI report. In the document it is proposed that CSI report event is triggered by indication from lower layer, and CSI report event shall be cancelled if the CSI report has been transmitted.

<CIT>, which is prior art under Article <NUM>(<NUM>) EPC, discloses apparatuses, methods, and systems for determining a resource for a channel state information report. In the document the method is described to include receiving, from a transmitter device, a channel state information reference signal within a data region and a channel state information request indicator in sidelink control information, determining, at a receiver device, a resource for transmitting a channel state information report in response to the channel state information request indicator using a mode <NUM> resource allocation procedure, a mode <NUM> resource allocation procedure, or a combination thereof, and transmitting, from the receiver device, the channel state information report via a medium access control element using the resource.

The present disclosure provides a method for performing SL communication between devices (or UEs), and device(s) (or UE(s)) performing the method.

The present disclosure provides a method for performing CSI reporting through a CSI MAC CE, and device(s) (or UE(s)) performing the method.

Based on the present disclosure, V2X communication between devices (or UEs) can be efficiently performed.

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

A slash (/) or comma used in the present disclosure may mean "and/or". For example, "A, B, C" may mean "A, B, or C".

In the present disclosure, "at least one of A and B" may mean "only A", "only B", or "both A and B". In addition, in the present disclosure, the expression "at least one of A or B" or "at least one of A and/or B" may be interpreted as "at least one of A and B".

In addition, in the present disclosure, "at least one of A, B, and C" may mean "only A", "only B", "only C", or "any combination of A, B, and C". In addition, "at least one of A, B, or C" or "at least one of A, B, and/or C" may mean "at least one of A, B, and C".

In addition, a parenthesis used in the present disclosure may mean "for example". Specifically, when indicated as "control information (PDCCH)", it may mean that "PDCCH" is proposed as an example of the "control information". In other words, the "control information" of the present disclosure is not limited to "PDCCH", and "PDCCH" may be proposed as an example of the "control information". In addition, when indicated as "control information (i.e., PDCCH)", it may also mean that "PDCCH" is proposed as an example of the "control information".

A technical feature described individually in one figure in the present disclosure may be individually implemented, or may be simultaneously implemented.

<FIG> shows a functional division between an NG-RAN and a 5GC, based on an embodiment of the present disclosure.

Referring to <FIG>, the gNB may provide functions, such as Inter Cell Radio Resource Management (RRM), Radio Bearer (RB) control, Connection Mobility Control, Radio Admission Control, Measurement Configuration & Provision, Dynamic Resource Allocation, and so on. An AMF may provide functions, such as Non Access Stratum (NAS) security, idle state mobility processing, and so on. A UPF may provide functions, such as Mobility Anchoring, Protocol Data Unit (PDU) processing, and so on. A Session Management Function (SMF) may provide functions, such as user equipment (UE) Internet Protocol (IP) address allocation, PDU session control, and so on.

Layers of a radio interface protocol between the UE and the network can be classified into a first layer (L1), a second layer (L2), and a third layer (L3) based on the lower three layers of the open system interconnection (OSI) model that is well-known in the communication system. Among them, a physical (PHY) layer belonging to the first layer provides an information transfer service by using a physical channel, and a radio resource control (RRC) layer belonging to the third layer serves to control a radio resource between the UE and the network. For this, the RRC layer exchanges an RRC message between the UE and the BS.

<FIG> and <FIG> show a radio protocol architecture, based on an embodiment of the present disclosure. The embodiment of <FIG> and <FIG> may be combined with various embodiments of the present disclosure. Specifically, <FIG> shows a radio protocol architecture for a user plane, and <FIG> shows a radio protocol architecture for a control plane. The user plane corresponds to a protocol stack for user data transmission, and the control plane corresponds to a protocol stack for control signal transmission.

Referring to <FIG> and <FIG>, a physical layer provides an upper layer with an information transfer service through a physical channel.

A radio resource control (RRC) layer is defined only in the control plane. The RRC layer serves to control the logical channel, the transport channel, and the physical channel in association with configuration, reconfiguration and release of RBs. The RB is a logical path provided by the first layer (i.e., the physical layer or the PHY layer) and the second layer (i.e., the MAC layer, the RLC layer, and the packet data convergence protocol (PDCP) layer) for data delivery between the UE and the network.

The physical channel includes several OFDM symbols in a time domain and several sub-carriers in a frequency domain. One sub-frame includes a plurality of OFDM symbols in the time domain. A resource block is a unit of resource allocation, and consists of a plurality of OFDM symbols and a plurality of sub-carriers. Further, each subframe may use specific sub-carriers of specific OFDM symbols (e.g., a first OFDM symbol) of a corresponding subframe for a physical downlink control channel (PDCCH), i.e., an L1/L2 control channel. A transmission time interval (TTI) is a unit time of subframe transmission.

Table <NUM> shown below represents an example of a number of symbols per slot (Nslotsymb), a number slots per frame (Nframe,uslot), and a number of slots per subframe (Nsubframe,uslot) based on an SCS configuration (u), in a case where a normal CP is used.

Meanwhile, a radio interface between a UE and another UE or a radio interface between the UE and a network may consist of an L1 layer, an L2 layer, and an L3 layer. In various embodiments of the present disclosure, the L1 layer may imply a physical layer. In addition, for example, the L2 layer may imply at least one of a MAC layer, an RLC layer, a PDCP layer, and an SDAP layer. In addition, for example, the L3 layer may imply an RRC layer.

The BWP may be a set of consecutive physical resource blocks (PRBs) in a given numerology. The PRB may be selected from consecutive sub-sets of common resource blocks (CRBs) for the given numerology on a given carrier.

When using bandwidth adaptation (BA), a reception bandwidth and transmission bandwidth of a UE are not necessarily as large as a bandwidth of a cell, and the reception bandwidth and transmission bandwidth of the BS may be adjusted. For example, a network/BS may inform the UE of bandwidth adjustment. For example, the UE receive information/configuration for bandwidth adjustment from the network/BS. In this case, the UE may perform bandwidth adjustment based on the received information/configuration. For example, the bandwidth adjustment may include an increase/decrease of the bandwidth, a position change of the bandwidth, or a change in subcarrier spacing of the bandwidth.

For example, the bandwidth may be decreased during a period in which activity is low to save power. For example, the position of the bandwidth may move in a frequency domain. For example, the position of the bandwidth may move in the frequency domain to increase scheduling flexibility. For example, the subcarrier spacing of the bandwidth may be changed. For example, the subcarrier spacing of the bandwidth may be changed to allow a different service. A subset of a total cell bandwidth of a cell may be called a bandwidth part (BWP). The BA may be performed when the BS/network configures the BWP to the UE and the BS/network informs the UE of the BWP currently in an active state among the configured BWPs.

Meanwhile, the BWP may be defined for SL. The same SL BWP may be used in transmission and reception. For example, a transmitting UE may transmit an SL channel or an SL signal on a specific BWP, and a receiving UE may receive the SL channel or the SL signal on the specific BWP. In a licensed carrier, the SL BWP may be defined separately from a Uu BWP, and the SL BWP may have configuration signaling separate from the Uu BWP. For example, the UE may receive a configuration for the SL BWP from the BS/network. The SL BWP may be (pre-)configured in a carrier with respect to an out-of-coverage NR V2X UE and an RRC_IDLE UE. For the UE in the RRC_CONNECTED mode, at least one SL BWP may be activated in the carrier.

<FIG> and <FIG> show a radio protocol architecture for a SL communication, based on an embodiment of the present disclosure. The embodiment of <FIG> and <FIG> may be combined with various embodiments of the present disclosure. More specifically, <FIG> shows a user plane protocol stack, and <FIG> shows a control plane protocol stack.

Hereinafter, a sidelink synchronization signal (SLSS) and synchronization information will be described.

The SLSS may include a primary sidelink synchronization signal (PSSS) and a secondary sidelink synchronization signal (SSSS), as an SL-specific sequence. The PSSS may be referred to as a sidelink primary synchronization signal (S-PSS), and the SSSS may be referred to as a sidelink secondary synchronization signal (S-SSS). For example, length-<NUM>-sequences may be used for the S-PSS, and length-<NUM> gold sequences may be used for the S-SSS. For example, a UE may use the S-PSS for initial signal detection and for synchronization acquisition. For example, the UE may use the S-PSS and the S-SSS for acquisition of detailed synchronization and for detection of a synchronization signal ID.

A physical sidelink broadcast channel (PSBCH) may be a (broadcast) channel for transmitting default (system) information which must be first known by the UE before SL signal transmission/reception. For example, the default information may be information related to SLSS, a duplex mode (DM), a time division duplex (TDD) uplink/downlink (UL/DL) configuration, information related to a resource pool, a type of an application related to the SLSS, a subframe offset, broadcast information, or the like. For example, for evaluation of PSBCH performance, in NR V2X, a payload size of the PSBCH may be <NUM> bits including <NUM>-bit CRC.

<FIG> shows a UE performing V2X or SL communication, based on an embodiment of the present disclosure.

Referring to <FIG>, in V2X or SL communication, the term 'UE' may generally imply a UE of a user. However, if a network equipment such as a BS transmits/receives a signal according to a communication scheme between UEs, the BS may also be regarded as a sort of the UE. For example, a UE <NUM> may be a first apparatus <NUM>, and a UE <NUM> may be a second apparatus <NUM>.

<FIG> and <FIG> show a procedure of performing V2X or SL communication by a UE based on a transmission mode, based on an embodiment of the present disclosure. The embodiment of <FIG> and <FIG> may be combined with various embodiments of the present disclosure. In various embodiments of the present disclosure, the transmission mode may be called a mode or a resource allocation mode. Hereinafter, for convenience of explanation, in LTE, the transmission mode may be called an LTE transmission mode. In NR, the transmission mode may be called an NR resource allocation mode.

For example, <FIG> shows a UE operation related to an LTE transmission mode <NUM> or an LTE transmission mode <NUM>. Alternatively, for example, <FIG> shows a UE operation related to an NR resource allocation mode <NUM>. For example, the LTE transmission mode <NUM> may be applied to general SL communication, and the LTE transmission mode <NUM> may be applied to V2X communication.

For example, <FIG> shows a UE operation related to an LTE transmission mode <NUM> or an LTE transmission mode <NUM>. Alternatively, for example, <FIG> shows a UE operation related to an NR resource allocation mode <NUM>.

Referring to <FIG>, in the LTE transmission mode <NUM>, the LTE transmission mode <NUM>, or the NR resource allocation mode <NUM>, a BS may schedule an SL resource to be used by the UE for SL transmission. For example, the BS may perform resource scheduling to a UE <NUM> through a PDCCH (more specifically, downlink control information (DCI)), and the UE 1may perform V2X or SL communication with respect to a UE <NUM> according to the resource scheduling. For example, the UE <NUM> may transmit a sidelink control information (SCI) to the UE <NUM> through a physical sidelink control channel (PSCCH), and thereafter transmit data based on the SCI to the UE <NUM> through a physical sidelink shared channel (PSSCH).

Referring to <FIG>, in the LTE transmission mode <NUM>, the LTE transmission mode <NUM>, or the NR resource allocation mode <NUM>, the UE may determine an SL transmission resource within an SL resource configured by a BS/network or a pre-configured SL resource. For example, the configured SL resource or the pre-configured SL resource may be a resource pool. For example, the UE may autonomously select or schedule a resource for SL transmission. For example, the UE may perform SL communication by autonomously selecting a resource within a configured resource pool. For example, the UE may autonomously select a resource within a selective window by performing a sensing and resource (re)selection procedure. For example, the sensing may be performed in unit of subchannels. In addition, the UE <NUM> which has autonomously selected the resource within the resource pool may transmit the SCI to the UE <NUM> through a PSCCH, and thereafter may transmit data based on the SCI to the UE <NUM> through a PSSCH.

<FIG> show three cast types, based on an embodiment of the present disclosure. Specifically, <FIG> shows broadcast-type SL communication, <FIG> shows unicast type-SL communication, and <FIG> shows groupcast-type SL communication. In case of the unicast-type SL communication, a UE may perform one-to-one communication with respect to another UE. In case of the groupcast-type SL transmission, the UE may perform SL communication with respect to one or more UEs in a group to which the UE belongs. In various embodiments of the present disclosure, SL groupcast communication may be replaced with SL multicast communication, SL one-to-many communication, or the like.

Meanwhile, in SL communication, a UE needs to efficiently select resource(s) for SL transmission. Hereinafter, based on various embodiments of the present disclosure, a method for a UE to efficiently select resource(s) for SL transmission and an apparatus supporting the same will be described. In various embodiments of the present disclosure, SL communication may include V2X communication.

At least one of the methods that are proposed based on the various embodiments of the present disclosure may be applied to at least one of unicast communication, groupcast communication, and/or broadcast communication.

At least one of the methods that are proposed based on the various embodiments of the present disclosure may be applied not only to PC5 interface or SL interface (e.g., PSCCH, PSSCH, PSBCH, PSSS/SSSS, and so on) based SL communication or V2X communication but also to Uu interface (e.g., PUSCH, PDSCH, PDCCH, PUCCH, and so on) based SL communication or V2X communication.

In the various embodiments of the present disclosure, receiving operation(s) of the UE may include decoding operation(s) and/or receiving operation(s) of SL channel(s) and/or SL signal(s) (e.g., PSCCH, PSSCH, PSFCH, PSBCH, PSSS/SSSS, and so on). Receiving operation(s) of the UE may include decoding operation(s) and/or receiving operation(s) of WAN DL channel(s) and/or WAN DL signal(s) (e.g., PDCCH, PDSCH, PSS/SSS, and so on). Receiving operation(s) of the UE may include sensing operation(s) and/or channel busy ratio (CBR) measuring operation(s). In the various embodiments of the present disclosure, sensing operation(s) of the UE may include PSSCH-RSRP measuring operation(s) based on PSSCH DM-RS sequence(s), PSSCH-RSRP measuring operation(s) based on PSSCH DM-RS sequence(s), which is scheduled by a PSCCH that is successfully decoded by the UE, sidelink RSSI (S-RSSI) measuring operation(s), and/or S-RSSI measuring operation(s) based on subchannel(s) related to V2X resource pool(s). In the various embodiments of the present disclosure, transmitting operation(s) of the UE may include transmitting operation(s) of SL channel(s) and/or SL signal(s) (e.g., PSCCH, PSSCH, PSFCH, PSBCH, PSSS/SSSS, and so on). Transmitting operation(s) may include transmitting operation(s) of WAN UL channel(s) and/or WAN UL signal(s) (e.g., PUSCH, PUCCH, SRS, and so on). In the various embodiments of the present disclosure, a synchronization signal may include an SLSS and/or a PSBCH.

In the various embodiments of the present disclosure, configuration may include signaling, signaling from a network, configuration from a network, and/or a pre-configuration from a network. In the various embodiments of the present disclosure, definition may include signaling, signaling from a network, configuration from a network, and/or a pre-configuration from a network. In the various embodiments of the present disclosure, designation may include signaling, signaling from a network, configuration from a network, and/or a pre-configuration from a network.

In the various embodiments of the present disclosure, ProSe Per Packet Priority (PPPP) may be replaced with ProSe Per Packet Reliability (PPPR), and PPPR may be replaced with PPPP. For example, as the PPPP value becomes smaller, this may indicate a high priority, and, as the PPPP value becomes greater, this may indicate a low priority. For example, as the PPPR value becomes smaller, this may indicate a high reliability, and, as the PPPR value becomes greater, this may indicate a low reliability. For example, a PPPP value related to a service, a packet or a message being related to a high priority may be smaller than a PPPP value related to a service, a packet or a message being related to a low priority. For example, a PPPR value related to a service, a packet or a message being related to a high reliability may be smaller than a PPPR value related to a service, a packet or a message being related to a low reliability.

In the various embodiments of the present disclosure, a session may include at least one of a unicast session (e.g., a unicast session for SL), a groupcast/multicast session (e.g., a groupcast/multicast session for SL), and/or a broadcast session (e.g., a broadcast session for SL).

In the various embodiments of the present disclosure, a carrier may be replaced with at least one of a BWP and/or a resource pool, or vice versa. For example, a carrier may include at least one of a BWP and/or a resource pool. For example, a carrier may include one or more BWPs. For example, a BWP may include one or more resource pools.

Meanwhile, NR sidelink supports CSI measurement/reporting between two UEs, and CSI measurement/reporting may be used for link adaptation between two UEs. For example, a UE2 which has received CSI-RS(s) from a UE1 may appropriately adjust Modulation and Coding Scheme (MCS) or select an appropriate precoding matrix by using channel state (e.g., a value related to the channel state) estimated based on the CSI-RS(s).

Meanwhile, in order to support CSI measurement/reporting in NR sidelink, agreements as shown in Table <NUM> were derived with respect to the sidelink CSI report in a recent 3GPP RAN2 conference.

Referring to Table <NUM>, in sidelink communication, a UE may report SL CSI to another UE through a MAC CE. That is, in communication between a base station and a UE, the UE reports CSI to the base station through L1 signaling (e.g., physical layer signaling), whereas in sidelink communication, the UE may report SL CSI to another UE through the MAC CE. Accordingly, if the SL MAC CE is defined together with a new logical channel ID (LCID), and if there is no appropriate resource for transmitting the SL MAC CE, the UE may trigger mode <NUM> resource scheduling (e.g., transmit SR to a base station), or the UE may perform mode <NUM> resource scheduling (e.g., sensing-based resource selection). For convenience of description, CSI transmitted/reported through the MAC CE may be referred to as a CSI MAC CE, a sidelink CSI MAC CE, or SL CSI. Meanwhile, the CSI MAC CE should be transmitted within a transmission latency bound of the UE in consideration of situations (e.g., prioritization, congestion control, etc.) related to transmission of the UE. For example, it is assumed that a packet delay budget (PDB) of packet(s) to be transmitted by the UE is <NUM>. In this case, the UE should transmit the CSI MAC CE within at least <NUM>. However, the latency bound of <NUM> is only a transmission latency bound of data to be transmitted by the UE, and the UE may have to transmit the CSI MAC CE within a time faster than <NUM>. For example, the UE may have to transmit the CSI MACE CE within a latency bound of about <NUM> to <NUM>.

Hereinafter, based on various embodiments of the present disclosure, a method for transmitting a CSI MAC CE and an apparatus supporting the same are proposed. Various embodiments proposed below may be applied to sidelink unicast communication. For convenience of description, although unicast communication is mainly described, various embodiments proposed below may be applied to other cast types (e.g., groupcast or broadcast). For example, if a PC5-RRC connection between UEs is established in groupcast or broadcast, CSI reporting may be performed between UEs. Accordingly, various embodiments proposed below may be applied not only to unicast communication but also to other cast type communication.

As described above, a PDB of SL CSI may have to have a value less than or equal to a PDB of data. More specifically, the PDB of the SL CSI may be less than or equal to the PDB of data to be guaranteed for service(s) between the two UEs. Herein, the PDB of data may refer to a specific parameter (e.g., Packet Delay Budget) among QoS information (e.g., standardized PQI information) for communication between two UEs in unicast communication. For example, Table <NUM> below may show a mapping between standardized PQI and QoS characteristics for sidelink service(s). For details related to Table <NUM>, refer to 3GPP TS <NUM> V16.

For example, referring to Table <NUM>, PQI value <NUM> supports platooning service, and should satisfy QoS characteristics such as priority level <NUM>, PDB <NUM>, Packet Error Rate (PER) <NUM>-<NUM>, etc. The QoS characteristics may be mapped to each radio bearer (RB). For example, if a PQI value related to a specific radio bearer (RB) is <NUM>, data transmitted/received on the specific RB should be transmitted/received to satisfy the QoS characteristics corresponding to the PQI value <NUM> of Table <NUM>.

However, the PDB of the SL CSI may be independent and may have a value less than or equal to the PDB indicated by the PQI value. For example, assuming that a PQI value mapped to an RB is <NUM>, a PDB mapped to the PQI value <NUM> may be <NUM>. However, if a UE1 transmits SL CSI to a UE2 within <NUM> which is the PDB of data, accuracy of channel estimation of the UE2 based on the SL CSI may be deteriorated. Therefore, even though the PDB of data is <NUM>, the UE1 may have to transmit the SL CSI to the UE2 within the earlier delay budget.

On the other hand, in the case of the PDB of the SL CSI, the UE may follow a PDB indicated by an LCH (or RB) related to data. In this case, if a MAC PDU is generated from multiple LCHs (or RBs), the PDB of the CSI may follow the minimum PDB value among them. For example, if a MAC PDU is generated from two LCHs and a CSI MAC CE is multiplexed into the MAC PDU, the PDB of the CSI MAC CE follows the minimum PDB value among the two LCHs.

As described above, in sidelink communication, both UEs may perform unicast communication. Herein, in unicast communication, a path for transmitting and receiving a specific service between UEs may be referred to as a session. For example, establishment of a session between two UEs means that a PC5-RRC connection between the two UEs is successfully established, and the two UEs can transmit and receive RRC information through the PC5-RRC connection.

Furthermore, in order for two UEs to transmit and receive multiple services in unicast communication, a plurality of unicast sessions may be established between the two UEs. Then, the two UEs may transmit and receive a PC5-RRC configuration for each session, and the two UEs may configure each session. In this case, each session may have different QoS characteristics.

<FIG> shows an example of a plurality of unicast links between two UEs.

Referring to <FIG>, two UEs may establish three sessions to transmit and receive three services. For example, PC5-RRC connection A, PC5-RRC connection B and PC5-RRC connection C may be established between a UE1 and a UE2.

For example, the UE1 and the UE2 may exchange information such as an RRC configuration, an AS configuration, a UE capability, etc., through each PC5-RRC connection. In addition, the UE1 and the UE2 may exchange different QoS information to be supported for each service. If the link A and the link B have different QoS characteristics in the embodiment of <FIG>, a PDB related to the link A and a PDB related to the link B may be different from each other. In this situation, the UE may have to determine a PDB of SL CSI.

For example, the PDB of the SL CSI may be configured for the UE to be a fixed value. For example, if the PDB of the SL CSI has a fixed value, the UE may determine the PDB of the SL CSI regardless of the PDB of each link. In addition, the UE may perform resource occupation based on the PDB of the SL CSI. In addition, the UE may transmit the SL CSI by using the occupied resource.

For example, the PDB of the SL CSI may be configured for the UE to be a value related to the PDB of each link. For example, if the PDB of the SL CSI is related to the PDB of each link, the UE may determine the minimum value among PDBs of the plurality of links as the PDB of the SL CSI. For example, if the PDB of the SL CSI is related to the PDB of each link, the UE may determine a value less than the minimum value among PDBs of a plurality of links as the PDB of the SL CSI.

For example, in the embodiment of <FIG>, it is assumed that a PDB of the link A is <NUM> and a PDB of the link B is <NUM>. In this case, the PDB of the SL CSI to be exchanged between the UE1 and the UE2 may have a value less than or equal to <NUM>. In this way, the PDB of the SL CSI may be related to the PQI mapped to each link or each RB. The UE may determine the PDB of the SL CSI as a value less than or equal to the PDB related to the PQI in consideration of the PQI of service(s) to be transmitted. In addition, the UE may perform resource occupation based on the determined PDB of the SL CSI. In addition, the UE may transmit the SL CSI by using the occupied resource.

Specifically, for example, the UE may perform resource occupation by using the selected PDB of the SL CSI. For example, if the PDB of the SL CSI has a value less than the PDB of the data, the UE operating based on resource allocation mode <NUM> may set a resource selection window having a shorter latency based on the minimum PDB among the PDB of the data and the PDB of the SL CSI, and the UE may select resource(s) related to sidelink communication within the resource selection window. For example, in the case of the UE operating based on resource allocation mode <NUM>, the UE may transmit QoS information to a base station through sidelinkUEinfomation. In this case, if the PDB of the SL CSI is set to be shorter than the PDB of the data, the UE should additionally transmit information on the PDB of the SL CSI to the base station. To this end, for example, the UE may additionally transmit the PDB of the SL CSI to the base station. Alternatively, the UE may additionally transmit an offset value between the minimum PDB of QoS information for data transmitted to the base station and the PDB of the SL CSI to the base station. Then, the base station may perform appropriate mode <NUM> resource allocation to the UE in consideration of the QoS information received from the UE.

In terms of resource occupation, more specifically, the UE may have to perform resource occupation or be allocated resource(s), by considering a PDB of a PQI related to data accumulated in each logical channel (LCH). For example, in the case of resource allocation mode <NUM>, the UE may set a resource selection window suitable for the PDB and select resource(s) within the resource selection window. In this case, if the UE generates one MAC PDU from a plurality of LCHs, a PDB of the MAC PDU may be the minimum PDB value among PDBs related to each LCH. Herein, for example, if data from an LCH1 (e.g., SDU <NUM>) and data from an LCH2 (e.g., SDU2) are multiplexed, the minimum PDB value may be the minimum value among PDB values related to each LCH. For example, if data from an LCH1 (e.g., SDU1) and a MAC CE (e.g., CSI MAC CE) are multiplexed, the minimum PDB value may be the minimum value among a PDB value related to the LCH1 and a PDB value related to the MAC CE. For example, if a MAC CE1 and a MAC CE2 are multiplexed, the minimum PDB value may be the minimum value among PDB values related to each MAC CE.

In addition, a high frequency band has severe channel variation due to radio characteristics. That is, the high frequency band has extreme channel frequency selective characteristic compared to a low frequency band. Therefore, since the high frequency band has more channel variation than the low frequency band, a sidelink UE transmitting/receiving a sidelink-related service in the high frequency band should transmit a SL CSI report relatively quickly. Therefore, in the case of the high frequency band, a smaller PDB value of the SL CSI than in the low frequency band may have to be applied. For example, beam transmission and reception such as mmWave may be performed in a sidelink high frequency band. In this case, a beam management process may be required for a TX UE and an RX UE to align their beams with each other. In this case, if the CSI-RS is configured for the UE, the UE may perform channel measurement and reporting by using the configured CSI-RS.

Therefore, based on an embodiment of the present disclosure, the PDB of the SL CSI may be different for each carrier. For example, if the PDB of the CSI MAC CE is fixedly determined, the PDB value of the SL CSI may be configured for each carrier range. For example, the PDB of the SL CSI configured for a carrier of a high frequency range may be smaller than the PDB of the SL CSI configured for a carrier of a low frequency range. For example, if the PDB of the CSI MAC CE is related to QoS mapped to data or an RB, a UE performing SL communication in a high frequency band may set or determine the PDB of the CSI MAC CE to a value smaller by a specific offset than a PDB mapped to data or an RB.

<FIG> shows an example of a procedure in which a base station, a first device, and a second device perform sidelink communication related to transmission of a sidelink CSI MAC CE.

For example, by triggering CSI reporting, the UE may generate a message to transmit the sidelink CSI MAC CE. For example, an upper layer (e.g., MAC layer) of the UE may generate the message to transmit the sidelink CSI MAC CE. In this case, if there is no SL grant to transmit the sidelink CSI MAC CE, the UE may trigger resource allocation. For example, in the case of a UE operating based on mode <NUM>, the UE may trigger and transmit a scheduling request (SR) and/or a buffer status report (BSR) in order to be allocated new resource(s) from the base station. Then, the base station may transmit SL grant(s) to the UE. Meanwhile, if the UE fails to receive SL grant(s) from the base station, the UE may cancel the triggered sidelink CSI MAC CE. Herein, for example, the failure of the UE to receive SL grant(s) may comprise that the UE receives SL grant(s) which cannot fulfil the minimum PDB determined for the sidelink MAC PDU or the PDB of the sidelink CSI MAC CE from the base station. That is, even if the UE receives SL grant(s) from the base station, if the UE determines/decides that transmission of the data or the sidelink CSI MAC CE based on the SL grant(s) allocated in consideration of a PDB exceeds the PDB, the UE may cancel the pending data or the pending sidelink CSI MAC CE. For example, in this case, the UE may not transmit the data or the sidelink CSI MAC CE. As described above, the reason why the UE cancels the transmission of the sidelink CSI MAC CE is that the up-to-dateness of the CSI information that should be sent quickly is not guaranteed even if the CSI information is transmitted at the next transmission opportunity.

Alternatively, for example, in case a UE performing sensing-based resource selection in the mode <NUM> operation selects a resource for sidelink CSI MAC CE transmission based on sensing, if the resource overlaps with a resource used by another UE and/or another UE occupies the resource with a higher priority, and/or a SL-RSRP value is higher than a specific threshold, the UE may cancel the selected resource. If the UE cancels the resource and reselects a new resource, the PDB of the data or the sidelink CSI MAC CE previously intended to be transmitted may be exceeded. In this case, the UE may cancel the pending data or the pending sidelink CSI MAC CE.

<FIG> shows an example of a procedure in which a base station, a first device, and a second device according to an embodiment perform sidelink communication related to transmission of a sidelink CSI MAC CE, based on the above examples. In step S1310, the first device according to an embodiment may receive Channel State Information-Reference Signal(s) (CSI-RS(s)) from the second device. In step S1320, the first device according to an embodiment may measure channel-related information based on the CSI-RS(s). In step S1330, the first device according to an embodiment may transmit a Scheduling Request (SR) or a Buffer Status Report (BSR) to the base station, based on the triggering of sidelink CSI Medium Access Control (MAC) Control Element (CE) transmission to the second device by the channel-related information measured based on the CSI-RS(s). In step S1340, the first device according to an embodiment may receive a SL grant related to the SR or the BSR from the base station. In step S1350, the first device according to an embodiment may cancel the triggered sidelink CSI MAC CE transmission to the second device, based on a latency bound related to the transmission of the sidelink CSI MAC CE and a time period based on the SL grant for the transmission of the sidelink CSI MAC CE.

<FIG> shows operations of a first device, based on an embodiment of the present disclosure.

The operations disclosed in the flowchart of <FIG> may be performed in combination with various embodiments of the present disclosure. For example, the operations disclosed in the flowchart of <FIG> may be performed based on at least one of devices illustrated in <FIG>. For example, the first device of <FIG> may be the first wireless device <NUM> of <FIG> to be described later. In another example, the first device of <FIG> may be the second wireless device <NUM> of <FIG> to be described later.

In step S1410, the first device according to an embodiment may receive, from a second device, a channel state information (CSI) - reference signal (RS).

In step S1420, the first device according to an embodiment may transmit, to a base station, a scheduling request (SR) or a buffer status report (BSR), based on triggering of sidelink CSI medium access control (MAC) control element (CE) transmission to the second device by channel-related information measured based on the CSI-RS.

For example, transmitting the SR or the BSR to the base station may comprise: transmitting the SR to the base station; receiving, from the base station, an uplink grant for the BSR related to the SR; and transmitting, to the base station, the BSR based on a resource informed by the uplink grant.

In step S1430, the first device according to an embodiment may receive, from the base station, a sidelink grant related to the SR or the BSR.

In step S1440, the first device according to an embodiment may cancel the triggered sidelink CSI MAC CE transmission to the second device, based on a latency bound related to the sidelink CSI MAC CE transmission and a time period based on the sidelink grant for the sidelink CSI MAC CE transmission.

For example, the latency bound may be replaced with a latency requirement, delay, latency, packet delay budget (PDB), etc..

For example, the triggered sidelink CSI MAC CE transmission to the second device may be canceled, based on the time period based on the sidelink grant for the sidelink CSI MAC CE transmission being located after a time at which the latency bound related to the sidelink CSI MAC CE transmission is expired.

For example, the triggered sidelink CSI MAC CE transmission to the second device may be canceled, based on a start time of the time period based on the sidelink grant for the sidelink CSI MAC CE transmission being located after a time at which the latency bound related to the sidelink CSI MAC CE transmission is expired.

For example, the triggered sidelink CSI MAC CE transmission to the second device may be canceled, based on an end time of the time period based on the sidelink grant for the sidelink CSI MAC CE transmission being located after a time at which the latency bound related to the sidelink CSI MAC CE transmission is expired.

For example, the latency bound related to the sidelink CSI MAC CE transmission may be less than or equal to a minimum latency bound for a sidelink MAC protocol data unit (PDU).

For example, canceling the triggered sidelink CSI MAC CE transmission to the second device may comprise: flushing sidelink CSI MAC CE in a buffer of the first device before transmitting the sidelink CSI MAC CE to the second device.

For example, a first unicast connection and a second unicast connection may be established between the first device and the second device. The latency bound related to the sidelink CSI MAC CE transmission may be determined to be a minimum value among a first unicast latency bound related to the first unicast connection and a second unicast latency bound related to the second unicast connection. In this case, the first unicast latency bound and the second unicast latency bound may be different.

For example, a third unicast latency bound may be set to the latency bound for the sidelink CSI MAC CE transmission based on establishment of a first unicast connection between the first device and the second device. In addition, a fourth unicast latency bound may be set to the latency bound for the sidelink CSI MAC CE transmission based on establishment of a second unicast connection between the first device and the second device. In addition, a fifth unicast latency bound may be set to the latency bound for the sidelink CSI MAC CE transmission based on establishment of the first unicast connection and the second unicast connection between the first device and the second device. In this case, the third unicast latency bound, the fourth unicast latency bound and the fifth unicast latency bound may be the same.

Based on an embodiment of the present disclosure, a first device configured to perform sidelink communication may be provided. The first device may comprise: at least one memory storing instructions; at least one transceiver; and at least one processor connected to the at least one memory and the at least one transceiver. The at least one processor may execute the instructions to: receive, from a second device, a channel state information (CSI) - reference signal (RS); transmit, to a base station, a scheduling request (SR) or a buffer status report (BSR), based on triggering of sidelink CSI medium access control (MAC) control element (CE) transmission to the second device by channel-related information measured based on the CSI-RS; receive, from the base station, a sidelink grant related to the SR or the BSR; and cancel the triggered sidelink CSI MAC CE transmission to the second device, based on a latency bound related to the sidelink CSI MAC CE transmission and a time period based on the sidelink grant for the sidelink CSI MAC CE transmission.

Based on an embodiment of the present disclosure, an apparatus (or chip (set)) configured to control a first user equipment (UE) may be provided. The apparatus may comprise: at least one processor; and at least one memory connected to the at least one processor and storing instructions. The at least one processor may execute the instructions to: receive, from a second UE, a channel state information (CSI) - reference signal (RS); transmit, to a base station, a scheduling request (SR) or a buffer status report (BSR), based on triggering of sidelink CSI medium access control (MAC) control element (CE) transmission to the second UE by channel-related information measured based on the CSI-RS; receive, from the base station, a sidelink grant related to the SR or the BSR; and cancel the triggered sidelink CSI MAC CE transmission to the second UE, based on a latency bound related to the sidelink CSI MAC CE transmission and a time period based on the sidelink grant for the sidelink CSI MAC CE transmission.

For example, the first UE of the embodiment may refer to the first device described in the present disclosure. For example, each of the at least one processor and the at least one memory in the apparatus configured to control the first UE may be implemented as a separate sub-chip, or at least two or more components may be implemented through one sub-chip.

Based on an embodiment of the present disclosure, a non-transitory computer-readable storage medium storing instructions may be provided. The instructions, when executed, may cause a first device to: receive, from a second device, a channel state information (CSI) - reference signal (RS); transmit, to a base station, a scheduling request (SR) or a buffer status report (BSR), based on triggering of sidelink CSI medium access control (MAC) control element (CE) transmission to the second device by channel-related information measured based on the CSI-RS; receive, from the base station, a sidelink grant related to the SR or the BSR; and cancel the triggered sidelink CSI MAC CE transmission to the second device, based on a latency bound related to the sidelink CSI MAC CE transmission and a time period based on the sidelink grant for the sidelink CSI MAC CE transmission.

<FIG> shows operations of a second device, based on an embodiment of the present disclosure.

The operations disclosed in the flowchart of <FIG> may be performed in combination with various embodiments of the present disclosure. For example, the operations disclosed in the flowchart of <FIG> may be performed based on at least one of devices illustrated in <FIG>. For example, the second device of <FIG> may be the second wireless device <NUM> of <FIG> to be described later. In another example, the second device of <FIG> may be the first wireless device <NUM> of <FIG> to be described later.

In step S1510, the base station according to an embodiment may receive, from a first device, a scheduling request (SR) or a buffer status report (BSR), based on triggering of sidelink channel state information (CSI) medium access control (MAC) control element (CE) transmission to a second device by the first device.

In step S1520, the base station according to an embodiment may transmit, to the first device, a sidelink grant related to the SR or the BSR.

For example, the sidelink CSI MAC CE transmission to the second device may be triggered by the first device based on channel-related information measured based on a CSI - reference signal (RS) received by the first device from the second device, and.

For example, based on a latency bound related to the sidelink CSI MAC CE transmission and a time period based on the sidelink grant for the sidelink CSI MAC CE transmission, the triggered sidelink CSI MAC CE transmission to the second device may be canceled by the first device.

Based on an embodiment of the present disclosure, a base station configured to perform wireless communication may be provided. The base station may comprise: at least one memory storing instructions; at least one transceiver; and at least one processor connected to the at least one memory and the at least one transceiver. The at least one processor may execute the instructions to: receive, from a first device, a scheduling request (SR) or a buffer status report (BSR), based on triggering of sidelink channel state information (CSI) medium access control (MAC) control element (CE) transmission to a second device by the first device; and transmit, to the first device, a sidelink grant related to the SR or the BSR, wherein the sidelink CSI MAC CE transmission to the second device is triggered by the first device based on channel-related information measured based on a CSI - reference signal (RS) received by the first device from the second device, and wherein, based on a latency bound related to the sidelink CSI MAC CE transmission and a time period based on the sidelink grant for the sidelink CSI MAC CE transmission, the triggered sidelink CSI MAC CE transmission to the second device is canceled by the first device.

Various embodiments of the present disclosure may be independently implemented. Alternatively, the various embodiments of the present disclosure may be implemented by being combined or merged. For example, although the various embodiments of the present disclosure have been described based on the 3GPP LTE system for convenience of explanation, the various embodiments of the present disclosure may also be extendedly applied to another system other than the 3GPP LTE system. For example, the various embodiments of the present disclosure may also be used in an uplink or downlink case without being limited only to direct communication between UEs. In this case, a base station, a relay node, or the like may use the proposed method according to various embodiments of the present disclosure. For example, it may be defined that information on whether to apply the method according to various embodiments of the present disclosure is reported by the base station to the UE or by a transmitting UE to a receiving UE through pre-defined signaling (e.g., physical layer signaling or higher layer signaling). For example, it may be defined that information on a rule according to various embodiments of the present disclosure is reported by the base station to the UE or by a transmitting UE to a receiving UE through pre-defined signaling (e.g., physical layer signaling or higher layer signaling). For example, some embodiments among various embodiments of the present disclosure may be applied limitedly only to a resource allocation mode <NUM>. For example, some embodiments among various embodiments of the present disclosure may be applied limitedly only to a resource allocation mode <NUM>.

<FIG> shows a communication system <NUM>, based on an embodiment of the present disclosure.

Referring to <FIG>, a communication system <NUM> to which various embodiments of the present disclosure are applied includes wireless devices, Base Stations (BSs), and a network. Herein, the wireless devices represent devices performing communication using Radio Access Technology (RAT) (e.g., <NUM> New RAT (NR)) or Long-Term Evolution (LTE)) and may be referred to as communication/radio/SG devices. The wireless devices may include, without being limited to, a robot 100a, vehicles 100b-<NUM> and 100b-<NUM>, an extended Reality (XR) device 100c, a hand-held device 100d, a home appliance 100e, an Internet of Things (IoT) device 100f, and an Artificial Intelligence (AI) device/server <NUM>. For example, the vehicles may include a vehicle having a wireless communication function, an autonomous vehicle, and a vehicle capable of performing communication between vehicles. Herein, the vehicles may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone). The XR device may include an Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality (MR) device and may be implemented in the form of a Head-Mounted Device (HMD), a Head-Up Display (HUD) mounted in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, etc. The hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or a smartglasses), and a computer (e.g., a notebook). For example, the BSs and the network may be implemented as wireless devices and a specific wireless device 200a may operate as a BS/network node with respect to other wireless devices.

Wireless communication/connections 150a, 150b, or 150c may be established between the wireless devices 100a to 100fBS <NUM>, or BS 200BS <NUM>. Herein, the wireless communication/connections may be established through various RATs (e.g., <NUM> NR) such as uplink/downlink communication 150a, sidelink communication 150b (or, D2D communication), or inter BS communication (e.g., relay, Integrated Access Backhaul (IAB)). The wireless devices and the BSs/the wireless devices may transmit/receive radio signals to/from each other through the wireless communication/connections 150a and 150b. For example, the wireless communication/connections 150a and 150b may transmit/receive signals through various physical channels. To this end, at least a part of various configuration information configuring processes, various signal processing processes (e.g., channel encoding/decoding, modulation/demodulation, and resource mapping/demapping), and resource allocating processes, for transmitting/receiving radio signals, may be performed based on the various proposals of the present disclosure.

<FIG> shows wireless devices, based on an embodiment of the present disclosure.

Hereinafter, hardware elements of the wireless devices <NUM> and <NUM> will be described more specifically, One or more protocol layers may be implemented by, without being limited to, one or more processors <NUM> and <NUM>.

<FIG> shows a signal process circuit for a transmission signal, based on an embodiment of the present disclosure.

<FIG> shows another example of a wireless device, based on an embodiment of the present disclosure.

<FIG> shows a hand-held device, based on an embodiment of the present disclosure. The hand-held device may include a smartphone, a smartpad, a wearable device (e.g., a smartwatch or a smartglasses), or a portable computer (e.g., a notebook). The hand-held device may be referred to as a mobile station (MS), a user terminal (UT), a Mobile Subscriber Station (MSS), a Subscriber Station (SS), an Advanced Mobile Station (AMS), or a Wireless Terminal (WT).

<FIG> shows a vehicle or an autonomous vehicle, based on an embodiment of the present disclosure. The vehicle or autonomous vehicle may be implemented by a mobile robot, a car, a train, a manned/unmanned Aerial Vehicle (AV), a ship, etc..

Claim 1:
A method for performing sidelink communication by a first device, the method comprising:
receiving, from a second device, information regarding a latency bound related to sidelink channel state information, CSI, medium access control, MAC, control element, CE, transmission,
wherein a respective latency bound is maintained for each of PC5 radio resource control, RRC, connections between the first device and the second device;
receiving, from the second device, a channel state information-reference signal, CSI-RS;
transmitting, to a base station, a scheduling request, SR, based on (i) triggering of the sidelink CSI MAC CE transmission to the second device and (ii) no sidelink grant for the sidelink CSI MAC CE transmission,
wherein a sidelink CSI MAC CE including channel-related information is obtained based on the CSI-RS;
receiving, from the base station, a sidelink grant related to the SR; and
canceling the triggered sidelink CSI MAC CE transmission to the second device, based on the sidelink grant which cannot fulfil the latency bound related to the sidelink CSI MAC CE transmission.