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 PCS 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.

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. Document: <NPL>), relates to resource allocation in 3GPP. Document: <NPL>), also relates to resource allocation in 3GPP.

Meanwhile, when the UE performs the re-evaluation operation for a transmission resource, a pre-determined time limit (e.g., a time gap between transmission resources that can be signaled by one SCI) may not be maintained for a transmission resource determined before the UE signals SCI, due to a transmission resource (RSC_REV) in which reselection is triggered/performed.

In one aspect, provided is a method according to claim <NUM>. For example, the second transmission resource may be a resource not reserved by the first device.

In one aspect, provided is a first device according to claim <NUM>. A further aspect provides a non-transitory computer-readable storage medium according to claim <NUM>.

The UE can efficiently perform SL communication.

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

In the present specification, "at least one of A and B" may mean "only A", "only B", or "both A and B". In addition, in the present specification, 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 specification, "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 specification 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 specification 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 specification may be individually implemented, or may be simultaneously implemented.

Layers of a radio interface protocol between the UE and the network can be classified into a first layer (layer <NUM>, L1), a second layer (layer <NUM>, L2), and a third layer (layer <NUM>, 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> shows a radio protocol architecture, based on an embodiment of the present disclosure. Specifically, (a) of <FIG> shows a radio protocol stack of a user plane for Uu communication, and (b) of <FIG> shows a radio protocol stack of a control plane for Uu communication. (c) of <FIG> shows a radio protocol stack of a user plane for SL communication, and (d) of <FIG> shows a radio protocol stack of a control plane for SL communication.

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., a MAC layer, an RLC layer, a packet data convergence protocol (PDCP) layer, and a service data adaptation protocol (SDAP) layer) for data delivery between the UE and the network.

<FIG> shows a structure of a radio frame of an NR, based on an embodiment of the present disclosure.

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,u slot) based on an SCS configuration (u), in a case where a normal CP is used.

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.

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. For example, the UE may receive a configuration for the Uu 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.

A sidelink synchronization signal (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 cyclic redundancy check (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> shows a procedure of performing V2X or SL communication by a UE based on a transmission mode, based on an embodiment 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, (a) of <FIG> shows a UE operation related to an LTE transmission mode <NUM> or an LTE transmission mode <NUM>. Alternatively, for example, (a) of <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, (b) of <FIG> shows a UE operation related to an LTE transmission mode <NUM> or an LTE transmission mode <NUM>. Alternatively, for example, (b) of <FIG> shows a UE operation related to an NR resource allocation mode <NUM>.

Referring to (a) of <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 (e.g., downlink control information (DCI)) or RRC signaling (e.g., Configured Grant Type <NUM> or Configured Grant Type <NUM>), and the UE <NUM> may 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 (b) of <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> shows three cast types, based on an embodiment of the present disclosure. Specifically, (a) of <FIG> shows broadcast-type SL communication, (b) of <FIG> shows unicast type-SL communication, and (c) of <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 the present disclosure, for example, a transmitting UE (TX UE) may be a UE which transmits data to a (target) receiving UE (RX UE). For example, the TX UE may be a UE which performs PSCCH transmission and/or PSSCH transmission. Additionally/alternatively, for example, the TX UE may be a UE which transmits SL CSI-RS(s) and/or a SL CSI report request indicator to the (target) RX UE. Additionally/alternatively, for example, the TX UE may be a UE which transmits a (control) channel (e.g., PSCCH, PSSCH, etc.) and/or reference signal(s) on the (control) channel (e.g., DM-RS, CSI-RS, etc.), to be used for a SL radio link monitoring (RLM) operation and/or a SL radio link failure (RLF) operation of the (target) RX UE.

Meanwhile, in the present disclosure, for example, a receiving UE (RX UE) may be a UE which transmits SL HARQ feedback to a transmitting UE (TX UE) based on whether decoding of data received from the TX UE is successful and/or whether detection/decoding of a PSCCH (related to PSSCH scheduling) transmitted by the TX UE is successful. Additionally/alternatively, for example, the RX UE may be a UE which performs SL CSI transmission to the TX UE based on SL CSI-RS(s) and/or a SL CSI report request indicator received from the TX UE. Additionally/alternatively, for example, the RX UE is a UE which transmits a SL (L1) reference signal received power (RSRP) measurement value, to the TX UE, measured based on (pre-defined) reference signal(s) and/or a SL (L1) RSRP report request indicator received from the TX UE. Additionally/alternatively, for example, the RX UE may be a UE which transmits data of the RX UE to the TX UE. Additionally/alternatively, for example, the RX UE may be a UE which performs a SL RLM operation and/or a SL RLF operation based on a (pre-configured) (control) channel and/or reference signal(s) on the (control) channel received from the TX UE.

Meanwhile, in the present disclosure, for example, in case the RX UE transmits SL HARQ feedback information for a PSSCH and/or a PSCCH received from the TX UE, the following options or some of the following options may be considered. Herein, for example, the following options or some of the following options may be limitedly applied only if the RX UE successfully decodes/detects a PSCCH scheduling a PSSCH.

Meanwhile, in the present disclosure, for example, the TX UE may transmit the following information or some of the following information to the RX UE through SCI(s). Herein, for example, the TX UE may transmit some or all of the following information to the RX UE through a first SCI and/or a second SCI.

Meanwhile, in the present disclosure, for example, since the TX UE may transmit a SCI, a first SCI and/or a second SCI to the RX UE through a PSCCH, the PSCCH may be replaced/substituted with the SCI and/or the first SCI and/or the second SCI. Additionally/alternatively, the SCI may be replaced/substituted with the PSCCH and/or the first SCI and/or the second SCI. Additionally/alternatively, for example, since the TX UE may transmit a second SCI to the RX UE through a PSSCH, the PSSCH may be replaced/substituted with the second SCI.

Meanwhile, in the present disclosure, for example, if SCI configuration fields are divided into two groups in consideration of a (relatively) high SCI payload size, the first SCI including a first SCI configuration field group may be referred to as a <NUM>st SCI, and the second SCI including a second SCI configuration field group may be referred to as a <NUM>nd SCI. Also, for example, the <NUM>st SCI may be transmitted to the receiving UE through a PSCCH. Also, for example, the <NUM>nd SCI may be transmitted to the receiving UE through a (independent) PSCCH or may be piggybacked and transmitted together with data through a PSSCH.

Meanwhile, in the present disclosure, for example, the term "configure/configured" or the term "define/defined" may refer to (pre)configuration from a base station or a network (through pre-defined signaling (e.g., SIB, MAC, RRC, etc.)) (for each resource pool).

Meanwhile, in the present disclosure, for example, since an RLF may be determined based on out-of-synch (OOS) indicator(s) or in-synch (IS) indicator(s), the RLF may be replaced/substituted with out-of-synch (OOS) indicator(s) or in-synch (IS) indicator(s).

Meanwhile, in the present disclosure, for example, an RB may be replaced/substituted with a subcarrier. Also, in the present disclosure, for example, a packet or a traffic may be replaced/substituted with a TB or a MAC PDU based on a transmission layer.

Meanwhile, in the present disclosure, a CBG may be replaced/substituted with a TB.

Meanwhile, in the present disclosure, for example, a source ID may be replaced/substituted with a destination ID.

Meanwhile, in the present disclosure, for example, an L1 ID may be replaced/substituted with an L2 ID. For example, the L1 ID may be an L1 source ID or an L1 destination ID. For example, the L2 ID may be an L2 source ID or an L2 destination ID.

Meanwhile, in the present disclosure, for example, an operation of the transmitting UE to reserve/select/determine retransmission resource(s) may include: an operation of the transmitting UE to reserve/select/determine potential retransmission resource(s) for which actual use will be determined based on SL HARQ feedback information received from the receiving UE.

Meanwhile, in the present disclosure, a sub-selection window may be replaced/substituted with a selection window and/or the pre-configured number of resource sets within the selection window, or vice versa.

Meanwhile, in the present disclosure, SL MODE <NUM> may refer to a resource allocation method or a communication method in which a base station directly schedules SL transmission resource(s) for a TX UE through pre-defined signaling (e.g., DCI or RRC message). For example, SL MODE <NUM> may refer to a resource allocation method or a communication method in which a UE independently selects SL transmission resource(s) in a resource pool pre-configured or configured from a base station or a network. For example, a UE performing SL communication based on SL MODE <NUM> may be referred to as a MODE <NUM> UE or MODE <NUM> TX UE, and a UE performing SL communication based on SL MODE <NUM> may be referred to as a MODE <NUM> UE or MODE <NUM> TX UE.

Meanwhile, in the present disclosure, for example, a dynamic grant (DG) may be replaced/substituted with a configured grant (CG) and/or a semi-persistent scheduling (SPS) grant, or vice versa. For example, the DG may be replaced/substituted with a combination of the CG and the SPS grant, or vice versa. For example, the CG may include at least one of a configured grant (CG) type <NUM> and/or a configured grant (CG) type <NUM>. For example, in the CG type <NUM>, a grant may be provided by RRC signaling and may be stored as a configured grant. For example, in the CG type <NUM>, a grant may be provided by a PDCCH, and may be stored or deleted as a configured grant based on L1 signaling indicating activation or deactivation of the grant.

Meanwhile, in the present disclosure, a channel may be replaced/substituted with a signal, or vice versa. For example, transmission/reception of a channel may include transmission/reception of a signal. For example, transmission/reception of a signal may include transmission/reception of a channel. In addition, for example, cast may be replaced/substituted with at least one of unicast, groupcast, and/or broadcast, or vice versa. For example, a cast type may be replaced/substituted with at least one of unicast, groupcast, and/or broadcast, or vice versa.

Meanwhile, in the present disclosure, a resource may be replaced/substituted with a slot or a symbol, or vice versa. For example, the resource may include a slot and/or a symbol.

Meanwhile, in the present disclosure, a priority may be replaced/substituted with at least one of logical channel prioritization (LCP), latency, reliability, minimum required communication range, prose per-packet priority (PPPP), sidelink radio bearer (SLRB), QoS profile, QoS parameter and/or requirement, or vice versa.

Meanwhile, in various embodiments of the present disclosure, the reservation resource and/or the selection resource may be replaced/substituted with a sidelink grant (SL GRANT).

Meanwhile, in various embodiments of the present disclosure, latency may be replaced/substituted with a packet delay budget (PDB).

Meanwhile, in various embodiments of the present disclosure, a message for triggering a report on sidelink channel state information/sidelink channel quality information (hereinafter, SL_CSI information) may be replaced/substituted with a sidelink channel state information reference signal (CSI-RS) reception.

Meanwhile, in the present disclosure, blind retransmission may refer that the TX UE performs retransmission without receiving SL HARQ feedback information from the RX UE. For example, SL HARQ feedback-based retransmission may refer that the TX UE determines whether to perform retransmission based on SL HARQ feedback information received from the RX UE. For example, if the TX UE receives NACK and/or DTX information from the RX UE, the TX UE may perform retransmission to the RX UE.

Meanwhile, in the present disclosure, for example, for convenience of description, a (physical) channel used when a RX UE transmits at least one of the following information to a TX UE may be referred to as a PSFCH.

Meanwhile, in the present disclosure, a Uu channel may include a UL channel and/or a DL channel. For example, the UL channel may include a PUSCH, a PUCCH, a sounding reference Signal (SRS), etc. For example, the DL channel may include a PDCCH, a PDSCH, a PSS/SSS, etc. For example, a SL channel may include a PSCCH, a PSSCH, a PSFCH, a PSBCH, a PSSS/SSSS, etc..

Meanwhile, in the present disclosure, sidelink information may include at least one of a sidelink message, a sidelink packet, a sidelink service, sidelink data, sidelink control information, and/or a sidelink transport block (TB). For example, sidelink information may be transmitted through a PSSCH and/or a PSCCH.

Meanwhile, in NR V2X communication or NR sidelink communication, a transmitting UE may reserve/select one or more transmission resources for sidelink transmission (e.g., initial transmission and/or retransmission), and the transmitting UE may transmit information on the location of the one or more transmission resources to receiving UE(s).

Meanwhile, when performing sidelink communication, a method for a transmitting UE to reserve or pre-determine transmission resource(s) for receiving UE(s) may be representatively as follows.

For example, the transmitting UE may perform a reservation of transmission resource(s) based on a chain. Specifically, for example, if the transmitting UE reserves K transmission resources, the transmitting UE may transmit location information for less than K transmission resources to receiving UE(s) through a SCI transmitted to the receiving UE(s) at any (or specific) transmission time or a time resource. That is, for example, the SCI may include location information for less than the K transmission resources. Alternatively, for example, if the transmitting UE reserves K transmission resources related to a specific TB, the transmitting UE may transmit location information for less than K transmission resources to receiving UE(s) through a SCI transmitted to the receiving UE(s) at any (or specific) transmission time or a time resource. That is, the SCI may include location information for less than the K transmission resources. In this case, for example, it is possible to prevent performance degradation due to an excessive increase in payloads of the SCI, by signaling only the location information for less than K transmission resources to the receiving UE(s) through one SCI transmitted at any (or specific) transmission time or the time resource by the transmitting UE.

<FIG> shows a method in which a UE that has reserved transmission resource(s) informs another UE of the transmission resource(s), based on an embodiment of the present disclosure.

Specifically, for example, (a) of <FIG> shows a method for performing by a transmitting UE chain-based resource reservation by transmitting/signaling location information of (maximum) <NUM> transmission resources to receiving UE(s) through one SCI, in the case of a value of K = <NUM>. For example, (b) of <FIG> shows a method for performing by a transmitting UE chain-based resource reservation by transmitting/signaling location information of (maximum) <NUM> transmission resources to receiving UE(s) through one SCI, in the case of a value of K = <NUM>. For example, referring to (a) and (b) of <FIG>, the transmitting UE may transmit/signal only location information of the fourth transmission-related resource to the receiving UE(s) through the fourth (or last) transmission-related PSCCH. For example, referring to (a) of <FIG>, the transmitting UE may transmit/signal to the receiving UE(s) not only location information of the fourth transmission-related resource but also location information of the third transmission-related resource additionally through the fourth (or last) transmission-related PSCCH. For example, referring to (b) of <FIG>, the transmitting UE may transmit/signal to the receiving UE(s) not only location information of the fourth transmission-related resource but also location information of the second transmission-related resource and location information of the third transmission-related resource additionally through the fourth (or last) transmission-related PSCCH. In this case, for example, in (a) and (b) of <FIG>, if the transmitting UE may transmit/signal to the receiving UE(s) only location information of the fourth transmission-related resource through the fourth (or last) transmission-related PSCCH, the transmitting UE may set or designate a field/bit of location information of unused or remaining transmission resource(s) to a pre-configured value (e.g., <NUM>). For example, in (a) and (b) of <FIG>, if the transmitting UE may transmit/signal to the receiving UE(s) only location information of the fourth transmission-related resource through the fourth (or last) transmission-related PSCCH, the transmitting UE may be set or designate a field/bit of location information of unused or remaining transmission resource(s) to a pre-configured status/bit value indicating/representing the last transmission (among <NUM> transmissions).

Meanwhile, for example, the transmitting UE may perform a reservation of transmission resource(s) based on a block. Specifically, for example, if the transmitting UE reserves K transmission resources, the transmitting UE may transmit location information for K transmission resources to receiving UE(s) through a SCI transmitted to the receiving UE(s) at any (or specific) transmission time or a time resource. That is, the SCI may include location information for K transmission resources. For example, if the transmitting UE reserves K transmission resources related to a specific TB, the transmitting UE may transmit location information for K transmission resources to receiving UE(s) through a SCI transmitted to the receiving UE(s) at any (or specific) transmission time or a time resource. That is, the SCI may include location information for K transmission resources. For example, (c) of <FIG> shows a method for performing by the transmitting UE block-based resource reservation, by signaling location information of <NUM> transmission resources to receiving UE(s) through one SCI, in the case of a value of K = <NUM>.

Based on an embodiment of the present disclosure, in the case of the transmitting UE performing the SL mode <NUM> operation, when the transmitting UE selects/reserves a transmission resource within N slots, the transmitting UE may divide a selection window which is determined based on a remaining latency budget related to a packet, into a pre-configured number. Herein, for example, the pre-configured number may be a value obtained by dividing the N value by the maximum number of time resources that can be signaled by one SCI. Or, for example, when the transmitting UE selects/reserves a transmission resource within N slots, the transmitting UE may divide a selection window which is determined based on a remaining latency budget related to a packet into a pre-configured length unit (e.g., the maximum time gap between transmission resources that can be signaled with one SCI) (hereinafter, K_VAL). Then, for example, the transmitting UE select "CEILING (N/K_VAL) (and/or FLOOR (N/K_VAL))" transmission resources, within a <NUM>-slot window (e.g., this may be interpreted as the maximum time gap between transmission resources that can be signaled by one SCI), per divided selection window. Herein, for example, when the above-described embodiment is applied, it may be interpreted that the condition requiring the selected/reserved transmission resources within different divided selection windows to be located within the <NUM>-slot window does not need to be satisfied. Additionally, for example, based on the above-described embodiment, the operation of selecting a transmission resource within a selection window related to a remaining latency budget of a packet may be triggered multiple number of times. For example, based on the above-described embodiment, the operation of selecting a transmission resource within a selection window related to a remaining latency budget of a packet may be triggered pre-configured number of times specifically for at least one of a resource pool, a service type, a QoS requirement (e.g., latency, reliability) or a resource pool congestion level.

Based on an embodiment of the present disclosure, among subchannels included in a resource pool, there may be exist a subchannel having a different frequency size (hereinafter, UNNOR_SB) as compared to other subchannels. Herein, for example, when a transmission resource is configured/selected within N slots, a related TB size may be determined based on the frequency size of a transmission resource of a pre-configured order signaled by SCI. For example, the pre-configured order may be the first or the last. Herein, for example, all of the transmission resources within N slots may be selected with the same number of subchannels. Additionally, for example, the sum of the number of RBs related to K subchannels included in a resource pool (hereinafter, POOL_RBNUM) may be smaller than the number of RBs included in a SL BWP (hereinafter, SYS_RBNUM). In this case, whether to regard the RBs of "SYS_RBNUM - POOL_RBNUM" as an independent subchannel, or whether to include the RBs of "SYS_RBNUM - POOL_RBNUM" as one of the existing K subchannels according to a pre-defined rule may be determined based on whether or not a "SYS_RBNUM - POOL_RBNUM" value exceeds a pre-configured threshold value and/or whether a "SYS_RBNUM - POOL_RBNUM" value is greater than or equal to the pre-configured number of PSCCH RBs. Herein, for example, if the "SYS_RBNUM - POOL_RBNUM" value is greater than the pre-configured threshold value, the RBs may be regarded as a single independent subchannel which is configured with "SYS_RBNUM - POOL_RBNUM" RBs. For example, if the "SYS_RBNUM - POOL_RBNUM" value is less than the pre-configured threshold value, the RBs may be included as one of the existing K subchannels (e.g., the frequency size of a subchannel additionally including the "SYS_RBNUM - POOL_RBNUM" RBs becomes larger than other subchannels). Or, for example, if the "SYS_RBNUM - POOL_RBNUM" value is greater than or equal to the pre-configured number of PSCCH RBs, the RBs may be regarded as a single independent subchannel which is configured with "SYS_RBNUM - POOL_RBNUM" RBs. For example, if the "SYS_RBNUM - POOL_RBNUM" value is less than the pre-configured number of PSCCH RBs, the RBs may be included as one of the existing K subchannels.

Based on an embodiment of the present disclosure, if a transmission resource reservation period is relatively short or shorter than a pre-configured threshold value, a transmission resource related to a specific or previous period may be allowed to be located within another or next period. For example, the transmission resource may include a retransmission resource. Herein, for example, if the above embodiment is applied, and if transmission resources related to different periods overlap in a time domain and/or a frequency domain, the UE may determine which transmission resource of which period to drop based on UE implementation. Or, for example, if transmission resources related to different periods overlap in a time domain and/or a frequency domain, the UE may determine which transmission resource of which period to drop based on a priority of a transmission packet, and the UE may drop a (period) resource related to a packet transmission with a (relatively) low priority. Or, for example, if transmission resources related to different periods overlap in a time domain and/or a frequency domain, the UE may drop a (re-)transmission resource related to a preceding period in the time domain. Or, for example, if transmission resources related to different periods overlap in a time domain and/or a frequency domain, the UE may drop a (re-)transmission resource related to a following period in the time domain. Additionally, for example, among the transmission resources related to different periods that overlap in the time domain and/or the frequency domain, if an unused transmission resource occurs due to the reception of ACK information through a PSFCH, packet transmission may be allowed through another overlapping transmission resource. For example, among the transmission resources related to different periods that overlap in the time domain and/or the frequency domain, if an unused transmission resource related to a packet with a relatively high priority occurs due to the reception of ACK information through a PSFCH, the UE may transmit the related packet through another overlapping transmission resource related to a packet with a relatively low priority. Or, for example, it may be configured such that a transmission resource related to a specific or previous period is not allowed to be located within another or next period. Or, for example, if a transmission resource related to a specific or previous period is located within another or next period, the UE may use the corresponding transmission resource for transmission of a new packet related to another or next period. Additionally, for example, when CR evaluation is performed for FDM transmission resources related to different periods overlapped in a time domain and/or a frequency domain, the UE may reflect the counted number of subchannels in the CR evaluation regardless of the overlapping. Or, in this case, for example, the UE reflect the number of subchannels in which the overlapping subchannels are counted only once in the CR evaluation. Or, in this case, for example, the UE may reflect the counted number of subchannels in the CR evaluation except for the subchannels related to the dropped transmission resource. Or, in this case, for example, the UE may include the subchannel related to the dropped transmission resource and reflect the counted number of subchannels in the CR evaluation.

Based on an embodiment of the present disclosure, a position of a PSSCH DMRS symbol and/or a SL CSI-RS mapping symbol may be determined by applying a pre-configured offset of an inverse direction based on a data symbol of a pre-configured order of a PSSCH. For example, the pre-configured order may be last. For example, the UE may transmit the PSSCH DMRS symbol and/or the SL CSI-RS mapping symbol in the location to which the pre-configured offset of the inverse direction is applied based on the data symbol of the pre-configured order of the PSSCH. Or, for example, candidate patterns of PSSCH DMRS symbols and/or SL CSI-RS mapping symbols may exist specifically for a resource pool. In this case, based on the number of symbols that can be actually used for PSSCH transmission by the UE, candidate patterns of PSSCH DMRS symbols and/or SL CSI-RS mapping symbols that can be selected finally may be limited. For example, based on the overhead of PSFCH resources, etc., depending on the number of symbols that can be actually used for PSSCH transmission by the UE, candidate patterns of PSSCH DMRS symbols and/or SL CSI-RS mapping symbols that can be selected finally may be implicitly limited.

Based on an embodiment of the present disclosure, in the case of the UE performing the re-evaluation operation, based on a transmission resource that has triggered re-selected/that has been re-selected (hereinafter, RSC_REV) due to an overlap of transmission resources of another UE, a transmission resource prior to being signaled by SCI, wherein a pre-determined/pre-configured time relation/restriction cannot be maintained, may be configured such that re-selection is triggered/performed together. For example, in the case of the UE performing the re-evaluation operation, due to RSC_REV, the UE-internally determined transmission resource prior to being signaled by the SCI (located after the RSC_REV time), wherein the pre-determined/pre-configured time relation/restriction cannot be maintained (e.g., the transmission resource in which the resource re-selection is not directly triggered by the re-evaluation operation) and/or the transmission resource that is signaled by SCI may be configured such that re-selection is triggered/performed together. For example, when the UE performs the re-evaluation operation, the UE may reselect a transmission resource before being signaled by SCI, in which the pre-determined/pre-configured time range is not maintained due to RSC_REV, together with RSC_REV. For example, if there is no selectable candidate transmission resource, wherein a pre-determined/pre-configured time relation/restriction can be maintained, re-selection for all transmission resources of the related SL grant may be triggered. Or, for example, in the case of the UE performing the re-evaluation operation, reselection for a determined transmission resource prior to being signaled by SCI that is located after the above-described RSC_REV and/or a transmission resource that is signaled by SCI may be triggered/performed. For example, the determined transmission resource prior to being signaled by the SCI may be a UE-internally determined transmission resource. Or, for example, in the case of the UE performing a periodic resource reservation, a resource related to a period that has already been signaled by SCI may be configured to be excluded from a re-evaluation based resource re-selection target. For example, in the case of the UE performing a periodic resource reservation, a resource related to a subsequent period that has already been signaled by SCI is configured to be excluded from a re-evaluation based resource re-selection target. For example, resource reselection based on re-evaluation may be performed for resources within the same period. For example, in the case of the UE reserving periodic resources, if a resource related to a period that has already been signaled by SCI needs to be reselected based on re-evaluation, all transmission resources of the related SL grant may be reselected. For example, in the case of the UE reserving periodic resources, if a resource related to a subsequent period that has already been signaled by SCI needs to be reselected based on re-evaluation, the UE may reselect all transmission resources of the SL grant related to RSC_REV.

Based on an embodiment of the present disclosure, if a transmission resource at a specific time needs to be reselected due to the pre-emption operation, all transmission resources of other times that have been signaled/scheduled by SCI transmission of the corresponding time may be configured to be reselected. For example, if the UE needs to reselect a transmission resource already signaled by SCI at a specific time due to the pre-emption operation, the UE may also reselect all transmission resources of other time that are signaled/scheduled by SCI transmission of the corresponding time. Or, for example, if a transmission resource at a specific time needs to be reselected due to the pre-emption operation, transmission resources at other time that have been signaled/scheduled by SCI transmission of the corresponding time may be configured to be excluded from reselection. For example, if the UE needs to reselect a transmission resource already signaled by SCI at a specific time due to the pre-emption operation, the UE may not reselect transmission resources of other times that are signaled/scheduled by SCI transmission of the corresponding time.

Meanwhile, in sidelink communication, when the UE performs re-evaluation, the UE may compare a threshold value and an RSRP value related to a sidelink resource to be re-evaluated. For example, if the RSRP value related to the sidelink resource is greater than the threshold value, the UE may exclude the sidelink resource from candidate resources. Herein, for example, the threshold value may be a value pre-configured by a combination of a priority related to the transmitting UE and/or a priority related to the receiving UE. Then, for example, the physical layer of the UE may report the re-evaluation of the sidelink resource to the MAC layer of the UE.

<FIG> shows a procedure in which a transmitting UE reselects a resource based on re-evaluation of the resource and performs sidelink communication with a receiving UE, based on an embodiment of the present disclosure. <FIG> shows an example of reselecting a resource based on a re-evaluated resource, based on an embodiment of the present disclosure. <FIG> shows an example of re-selecting a periodic resource based on a re-evaluated periodic resource, based on an embodiment of the present disclosure. The embodiments of <FIG> may be combined with various embodiments of the present disclosure.

Referring to <FIG>, in step S1110, the transmitting UE may perform resource re-evaluation for a transmission resource for performing sidelink communication. For example, the transmission resource may be a first transmission resource.

In step S1120, the transmitting UE may reselect the transmission resource based on the re-evaluation. For example, the transmitting UE may reselect the first transmission resource based on the re-evaluation. For example, the transmitting UE may reselect a second transmission resource based on the reselection of the first transmission resource. For example, the second transmission resource may be a resource selected by the transmitting UE before the first transmission resource is reselected. For example, the second transmission resource may be a resource not reserved by the transmitting UE. For example, the resource not reserved by the transmitting UE may be a resource before SCI including information related to the reservation of the transmission resource is transmitted by the transmitting UE. For example, the second transmission resource may be a resource before the SCI including information related to the reservation of the second transmission resource is transmitted by the transmitting UE.

Specifically, referring to <FIG>, for example, the second transmission resource may exceed a pre-determined time range by the reselected first transmission resource. For example, the reselected second transmission resource may be located within the pre-determined time range. For example, the pre-determined time range may be a maximum time gap between transmission resources that can be signaled by one SCI. For example, the maximum time gap between transmission resources that can be signaled by one SCI may be <NUM> slots. For example, a time gap between the reselected first transmission resource and the reselected second transmission resource may be a value within <NUM> slots. For example, the transmitting UE may reselect a third transmission resource located after the first transmission resource. For example, the third transmission resource may be a resource before the SCI including information related to the reservation of the third transmission resource is transmitted by the transmitting UE. For example, if the third transmission resource is a resource in which SCI including information related to the reservation of the third transmission resource is transmitted by the transmitting UE, the transmitting UE may exclude the third transmission resource from the re-evaluation based resource reselection target.

For example, based on no candidate transmission resource within the pre-determined time range, all transmission resources allocated by a sidelink grant related to the first transmission resource may be reselected.

For example, based on transmission resources being periodically reserved by the transmitting UE, a transmission resource related to a second period following a first period may not be reselected. For example, the first period may be a period including the first transmission resource. The following second period may include a resource in which SCI including information related to the reservation of the transmission resource is transmitted by the transmitting UE.

Alternatively, for example, based on transmission resources being periodically reserved by the transmitting UE, a transmission resource in the second period following the first period may be reselected. For example, the first period may include the first transmission resource. For example, the following second period may include a resource in which SCI including information related to the reservation of the transmission resource is transmitted by the transmitting UE. In this case, for example, all transmission resources allocated by a sidelink grant related to the first transmission resource may be reselected.

Referring to <FIG>, if the transmitting UE performs re-evaluation for a first transmission resource and re-selection of the first transmission resource is triggered, the transmitting UE may reselect a second transmission resource within a first period. For example, if the transmitting UE performs re-evaluation for the first transmission resource and reselection of the first transmission resource is triggered, the transmitting UE may not reselect a transmission resource within a period other than the first period. For example, if SCI including information related to the reservation of the transmission resource included in a second period is already signaled, the transmitting UE may exclude a transmission resource included in the second period from the re-evaluation based resource reselection target. Or, for example, if the transmitting UE needs to reselect a transmission resource within a period other than the first period, the transmitting UE may reselect all transmission resources allocated by a sidelink grant related to the first transmission.

In step S1130, the transmitting UE may transmit a PSCCH to the receiving UE based on the reselected resource. For example, the transmitting UE may transmit SCI to the receiving UE through the PSCCH. For example, the SCI may include information related to the reservation of the transmission resource. In step S1140, the transmitting UE may transmit a PSSCH related to the PSCCH to the receiving UE based on the reselected resource.

Additionally, for example, a reselection check procedure for a transmission resource in a resource pool selected for a sidelink process may be triggered for the transmitting UE. In this case, for example, while the transmitting UE performs reselection triggered by re-evaluation indicated by the physical layer, the transmitting UE may reselect the pre-selected but unreserved resource. Also, for example, while reselection triggered by re-evaluation indicated by the physical layer is performed, the operation of reselecting the pre-selected but unreserved resource may be an implementation of the UE.

<FIG> shows a method for a first device to perform resource reselection based on re-evaluation of a first transmission resource, based on an embodiment of the present disclosure.

Referring to <FIG>, in step S1410, the first device <NUM> may perform re-evaluation for a first transmission resource for performing sidelink communication. In step S1420, the first device <NUM> may reselect the first transmission resource based on the re-evaluation.

In step S1430, the first device <NUM> may reselect a second transmission resource based on the reselection of the first transmission resource. For example, the second transmission resource may be a resource selected by the first device <NUM> before the first transmission resource is reselected. For example, the second transmission resource may be a resource not reserved by the first device <NUM>. For example, the second transmission resource may be a resource before SCI including information related to reservation of the second transmission resource is transmitted by the first device <NUM>. For example, the second transmission resource may exceed a pre-determined time range. For example, the reselected second transmission resource may be located within the pre-determined time range. For example, the pre-determined time range may be the maximum time between transmission resources that can be indicated by one SCI. For example, the maximum time gap between transmission resources that can be indicated by one SCI may be <NUM> slots. For example, based on no candidate transmission resource within the pre-determined time range, all transmission resources allocated by a sidelink grant related to the first transmission resource may be reselected.

For example, a third transmission resource located after the first transmission resource may be reselected. For example, the third transmission resource may be a resource before SCI including information related to reservation of the third transmission resource is transmitted by the first device <NUM>.

For example, based on a periodic transmission resource reservation by the first device <NUM>, a transmission resource related to a second period following a first period may not be reselected. For example, the first period may include the first transmission resource. For example, the second period may include a resource in which SCI including information related to reservation of a transmission resource is transmitted by the first device <NUM>.

For example, based on a periodic transmission resource reservation by the first device <NUM>, a transmission resource within a second period following a first period may be reselected. For example, the first period may include the first transmission resource. For example, the second period may include a resource in which SCI including information related to reservation of a transmission resource is transmitted by the first device <NUM>. For example, all transmission resources allocated by a sidelink grant related to the first transmission resource may be reselected.

The proposed method may be applied to the device(s) based on various embodiments of the present disclosure. First, the processor <NUM> of the first device <NUM> may perform re-evaluation for a first transmission resource for performing sidelink communication. In addition, the processor <NUM> of the first device <NUM> may reselect the first transmission resource based on the re-evaluation. In addition, the processor <NUM> of the first device <NUM> may reselect a second transmission resource based on the reselection of the first transmission resource.

Based on an embodiment of the present disclosure, a first device adapted to perform wireless communication may be provided. For example, the first device may comprise: one or more memories storing instructions; one or more transceivers; and one or more processors connected to the one or more memories and the one or more transceivers.

Based on an embodiment of the present disclosure, an apparatus adapted to control a first user equipment (UE) may be provided. For example, the apparatus may comprise: one or more processors; and one or more memories operably connected to the one or more processors and storing instructions. For example, the one or more processors may execute the instructions to: perform re-evaluation for a first transmission resource for performing sidelink communication; reselect the first transmission resource based on the re-evaluation; and reselect a second transmission resource based on the reselection of the first transmission resource. For example, the second transmission resource may be a resource selected by the first UE before the first transmission resource is reselected. For example, the second transmission resource may be a resource not reserved by the first UE.

Based on an embodiment of the present disclosure, a non-transitory computer-readable storage medium storing instructions may be provided. For example, the non-transitory computer-readable storage medium storing instructions, when executed, may cause a first device to: perform re-evaluation for a first transmission resource for performing sidelink communication; reselect the first transmission resource based on the re-evaluation; and reselect a second transmission resource based on the reselection of the first transmission resource. For example, the second transmission resource may be a resource selected by the first device before the first transmission resource is reselected. For example, the second transmission resource may be a resource not reserved by the first device.

<FIG> shows a method for a second device to perform sidelink communication with a first device, based on an embodiment of the present disclosure.

Referring to <FIG>, in step S1510, the second device <NUM> may perform sidelink communication with the first device <NUM> based on a reselected first transmission resource and a reselected second transmission resource. For example, a first transmission resource may be re-evaluated, and the first transmission resource may be reselected based on the re-evaluation. For example, based on the reselection of the first transmission resource, the second transmission resource may be reselected. For example, the second transmission resource may be a resource selected by the first device before the first transmission resource is reselected, and the second transmission resource may be a resource not reserved by the first device.

For example, the second transmission resource may be a resource before SCI including information related to reservation of the second transmission resource is transmitted by the first device <NUM>. For example, the second transmission resource may exceed a pre-determined time range. For example, the reselected second transmission resource may be located within the pre-determined time range. For example, the pre-determined time range may be the maximum time between transmission resources that can be indicated by one SCI. For example, the maximum time gap between transmission resources that can be indicated by one SCI may be <NUM> slots. For example, based on no candidate transmission resource within the pre-determined time range, all transmission resources allocated by a sidelink grant related to the first transmission resource may be reselected.

The proposed method may be applied to the device(s) based on various embodiments of the present disclosure. For example, the processor <NUM> of the second device <NUM> may control the transceiver <NUM> to perform sidelink communication with the first device <NUM> based on the reselected first transmission resource and the reselected second transmission resource.

Based on an embodiment of the present disclosure, a second device adapted to perform wireless communication may be provided. For example, the second device may comprise: one or more memories storing instructions; one or more transceivers; and one or more processors connected to the one or more memories and the one or more transceivers. For example, the one or more processors may execute the instructions to: perform sidelink communication with the first device based on a reselected first transmission resource and a reselected second transmission resource. For example, a first transmission resource may be re-evaluated, and the first transmission resource may be reselected based on the re-evaluation. For example, based on the reselection of the first transmission resource, the second transmission resource may be reselected. For example, the second transmission resource may be a resource selected by the first device before the first transmission resource is reselected, and the second transmission resource may be a resource not reserved by the first device.

Various embodiments of the present disclosure may be combined with each other.

<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/<NUM> 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.

Here, wireless communication technology implemented in wireless devices 100a to 100f of the present disclosure may include Narrowband Internet of Things for low-power communication in addition to LTE, NR, and <NUM>. In this case, for example, NB-IoT technology may be an example of Low Power Wide Area Network (LPWAN) technology and may be implemented as standards such as LTE Cat NB1, and/or LTE Cat NB2, and is not limited to the name described above. Additionally or alternatively, the wireless communication technology implemented in the wireless devices 100a to 100f of the present disclosure may perform communication based on LTE-M technology. In this case, as an example, the LTE-M technology may be an example of the LPWAN and may be called by various names including enhanced Machine Type Communication (eMTC), and the like. For example, the LTE-M technology may be implemented as at least any one of various standards such as <NUM>) LTE CAT <NUM>, <NUM>) LTE Cat M1, <NUM>) LTE Cat M2, <NUM>) LTE non-Bandwidth Limited (non-BL), <NUM>) LTE-MTC, <NUM>) LTE Machine Type Communication, and/or <NUM>) LTE M, and is not limited to the name described above. Additionally or alternatively, the wireless communication technology implemented in the wireless devices 100a to 100f of the present disclosure may include at least one of Bluetooth, Low Power Wide Area Network (LPWAN), and ZigBee considering the low-power communication, and is not limited to the name described above. As an example, the ZigBee technology may generate personal area networks (PAN) related to small/low-power digital communication based on various standards including IEEE <NUM>. <NUM>, and the like, and may be called by various names.

Wireless communication/connections 150a, 150b, or 150c may be established between the wireless devices 100a to 100f/BS <NUM>, or BS <NUM>/BS <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.

<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..

For example, the communication unit <NUM> may receive map data, traffic information data, etc. from an external server. The autonomous driving unit 140d may generate an autonomous driving path and a driving plan from the obtained data. The control unit <NUM> may control the driving unit 140a such that the vehicle or the autonomous vehicle <NUM> may move along the autonomous driving path according to the driving plan (e.g., speed/direction control). In the middle of autonomous driving, the communication unit <NUM> may aperiodically/periodically acquire recent traffic information data from the external server and acquire surrounding traffic information data from neighboring vehicles. In the middle of autonomous driving, the sensor unit 140c may obtain a vehicle state and/or surrounding environment information. The autonomous driving unit 140d may update the autonomous driving path and the driving plan based on the newly obtained data/information. The communication unit <NUM> may transfer information about a vehicle position, the autonomous driving path, and/or the driving plan to the external server. The external server may predict traffic information data using AI technology, etc., based on the information collected from vehicles or autonomous vehicles and provide the predicted traffic information data to the vehicles or the autonomous vehicles.

Claim 1:
A method for performing wireless communication by a first device, the method comprising:
transmitting sidelink control information including resource allocation information and resource reservation period information;
performing (S1410) re-evaluation for a first transmission resource for performing sidelink communication;
reselecting (S1420) the first transmission resource based on the re-evaluation; and
reselecting (S1430) a second transmission resource based on the reselection of the first transmission resource,
wherein the second transmission resource is a resource selected by the first device before the first transmission resource is reselected,
wherein the second transmission resource is a resource not reserved by the first device, and
wherein a third transmission resource in only one subsequent period that has already been signaled by the sidelink control information is not subject to the re-evaluation.