Abstract: A method and apparatus for performing a sidelink Hybrid Automatic Repeat Request (HARQ) operation are provided. The method may include establishing a communication session through an upper layer signaling; receiving configuration information for a HARQ operation through the upper layer; receiving downlink control information (DCI) from a network; transmitting sidelink data through a sidelink channel based on the received DCI; and receiving a response to the sidelink data.

Abstract: Provided is a method and apparatus for performing a random access procedure. A wireless device may transmit a random access preamble and may monitor for a random access response. The wireless device may determine to transmit a second random access preamble or to transmit uplink data responsive to the random access response. A time for preparing the second random access preamble may be determined based on a subcarrier spacing associated with the random access preamble or a subcarrier spacing associated a downlink channel associated with the random access response. A time for preparing the uplink data may be determined based on a subcarrier spacing associated with the uplink data or a subcarrier spacing associated a downlink channel associated with the random access response.

Abstract: The present disclosure provides a method for performing HARQ retransmission by a terminal supporting V2X communication in a wireless communication system. The method for performing HARQ retransmission may comprise the steps of: transmitting data by a transmission terminal in a pre-configured resource; receiving, by the transmission terminal, a NACK response to the data from a reception terminal; and retransmitting the data by the transmission terminal after changing an NDI value based on a resource dynamically allocated from a base station.

Abstract: A method and apparatus for supporting a device-to-device (D2D) communication between user equipments (UEs) are provided. The method of a device-to-device (D2D) communication between user equipments (UEs), the method includes: receiving, at a transmission (Tx) UE, resource assignment information transmitted from an evolved NodeB (eNB), the resource assignment information being associated with a D2D discovery signal to be transmitted in a discovery period; determining, at the Tx UE, that a D2D discovery signal associated with a first discovery type and a D2D discovery signal associated with a second discovery type are to be transmitted in a first subframe included in the discovery period; and in the first subframe, transmitting the D2D discovery signal associated with the second discovery type and dropping the D2D discovery signal associated with the first discovery type.

Abstract: One or more synchronization procedures in wireless communications are provided. A wireless user device may determine a global navigation satellite system (GNSS) as a synchronization reference source associated with a sidelink synchronization. The wireless user device may determine, based on the GNSS being the synchronization reference source associated with a sidelink synchronization and a subcarrier spacing index for sidelink, a slot number for sidelink communication. The wireless user device may transmit, based on the slot number, a sidelink synchronization signal from the wireless user device to a second wireless user device.

Abstract: Exemplary embodiments provide a method and apparatus for transmitting data through a device-to-device (D2D) communication between user equipments (UEs), the method including: generating, at a first UE, first D2D data, the first D2D data corresponding to a transport block (TB) unit; and transmitting, from the first UE to a second UE, the first D2D data through at least one D2D communication resource, the at least one D2D communication resource being based on a sub-RPT (sub-resource pattern for transmission). An RPT defined in a D2D resource pool is configured based on the sub-RPT, and the sub-RPT indicates the at least one D2D communication resource for the transmission of the first D2D data among at least two D2D communication candidate resources.

Abstract: A method, apparatus, and system for generating and transmitting a physical broadcast channel (PBCH) are provided. A base station may perform a first scrambling process on PBCHs in a time period before a channel coding, and perform a second scrambling process after the channel coding. PHCH payloads and PBCH DMRS may provide information bits to be used in the scrambling processes.

Abstract: A method of performing, by a terminal, a Hybrid Automatic Repeat and Request (HARQ) feedback procedure in a new radio (NR) vehicle-to-everything (V2X) system may include receiving sidelink (SL) data from a transmitting (Tx) terminal, determining a PSFCH resource including feedback information about the received sidelink data, and transmitting a PSFCH to the Tx terminal through the determined PSFCH resource.

Abstract: Provided is a method and apparatus for using an offset between a synchronization signal block and a resource block grid. The method may include receiving, by a user device, a synchronization signal (SS) block comprising a synchronization signal and a physical broadcast channel (PBCH), determining, from the PBCH, a value of a subcarrier offset between the SS block and an RB grid, determining, based on the value of the subcarrier offset and a frequency location of the SS block, the RB grid, and decoding, based on the determined RB grid, one or more of a reference signal, a control channel, or a data channel.

Abstract: Exemplary embodiments provide a method and apparatus for transmitting a synchronization signal for Device-to-Device (D2D) communication in a wireless communication system. With respect to a D2D synchronization source to transmit a synchronization signal for D2D communication, the method includes: generating a D2D Synchronization Signal (D2DSS); and transmitting, by a synchronization source, the D2DSS to a D2D reception (Rx) UE, wherein the D2DSS includes a Primary D2D Synchronization Signal (PD2DSS) generated based on information associated with the synchronization source.

Abstract: According to an aspect of the present disclosure, there is provided a method of transmitting feedback information from a user equipment (UE) in a new radio (NR) vehicle-to-everything (V2X) system. Here, the method of transmitting feedback information may include performing, by a first UE and a second UE, a session establishment process based on at least one of unicast and groupcast; exchanging, by the first UE and the second UE, ID information in the session establishment process; and completing, by the first UE and the second UE, the session establishment. Here, when the first UE and the second UE complete the session establishment, a physical layer ID representing a session may be determined.

Abstract: A communication method of a terminal with another terminal through a sidelink comprises: determining, by a first user device, one or more radio resource control (RRC) configurations comprising information of a demodulation reference signal (DMRS) for vehicle-to-everything (V2X) communication between user devices; determining, based on the one or more RRC configurations, a Physical Sidelink Control Channel (PSCCH) DMRS for a PSCCH; determining, based on a cyclic redundancy code of the PSCCH, an identifier; determining, based on the identifier, an initialization value associated with a Physical Sidelink Shared Channel (PSSCH) DMRS for a PSSCH; and via one or more orthogonal frequency division multiplexing (OFDM) symbols, transmitting, by the first user device to a second user device, the PSCCH DMRS and the PSSCH DMRS.

Abstract: Disclosed is a method and apparatus for generating information indicating a synchronization signal (SS) block. A method comprises: determining a frequency resource associated with a wireless device; determining, by a base station and based on the determined frequency resource, whether to add or omit a first bitmap indicating a plurality of groups in which at least one synchronization signal (SS) block is transmitted: generating, based on the determining to add the first bitmap, system information comprising a parameter comprising: the first bitmap; and a second bitmap indicating a position of one or more transmission SS blocks in each of the plurality of groups; and transmitting, based on the position, the one or more transmission SS blocks each comprising a Physical Broadcast Channel (PBCH) and a synchronization signal.

Abstract: Disclosed is a method and apparatus for generating information indicating a synchronization signal (SS) block. A method comprises: determining a frequency resource associated with a wireless device; determining, by a base station and based on the determined frequency resource, whether to add or omit a first bitmap indicating a plurality of groups in which at least one synchronization signal (SS) block is transmitted: generating, based on the determining to add the first bitmap, system information comprising a parameter comprising: the first bitmap; and a second bitmap indicating a position of one or more transmission SS blocks in each of the plurality of groups; and transmitting, based on the position, the one or more transmission SS blocks each comprising a Physical Broadcast Channel (PBCH) and a synchronization signal.

Abstract: A method of transmitting uplink data is provided. The method includes establishing connections with a first serving cell and a second serving cell, determining, by a user equipment (UE), a time period for a device-to-device (D2D) discovery signal communication via the second serving cell, determining, by the UE and based on an uplink grant received via the first serving cell, a first subframe associated with an uplink signal to an evolved NodeB (eNB) associated with the first serving cell, and in response to determining that the first subframe overlaps in time with the time period, refraining from transmitting the uplink signal in the first subframe, and transmitting, based on a retransmission timing, the uplink signal.

Abstract: A communication method of a terminal with another terminal through a sidelink may provide information related to a demodulation reference signal (DMRS). A user device may demodulate a Physical Sidelink Control Channel (PSCCH) DMRS and a Physical Sidelink Shared Channel (PSSCH) DMRS, and may demodulate a PSCCH based on the demodulated PSCCH DMRS and demodulate a PSSCH based on the demodulated PSSCH DMRS.

Abstract: The present disclosure provides a method for performing HARQ retransmission by a terminal supporting V2X communication in a wireless communication system. The method for performing HARQ retransmission may comprise the steps of: transmitting data by a transmission terminal in a pre-configured resource; receiving, by the transmission terminal, a NACK response to the data from a reception terminal; and retransmitting the data by the transmission terminal after changing an NDI value based on a resource dynamically allocated from a base station.

Abstract: Exemplary embodiments provide a method and apparatus for transmitting a synchronization signal for Device-to-Device (D2D) communication in a wireless communication system. The method includes: receiving, at a first UE, a D2D synchronization signal transmitted from a second UE, the D2D synchronization signal comprising a primary D2D synchronization signal (PD2DSS) and a secondary D2D synchronization signal (SD2DSS); determining a root index based on the received PD2DSS; and determining a type of a synchronization source based on the root index. The root index corresponds to an integer value X when the type of synchronization source is associated with D2DSSue_net. The root index corresponds to an integer value Y when the type of synchronization source is associated with D2DSSue_oon. Each of the integer value X and integer value Y is not an element of a set {25, 29, 34}.

Abstract: A method includes generating a first DM-RS for V2X communication and a second DM-RS for V2X communication, the first DM-RS for V2X communication being mapped in a first symbol in a first slot of a subframe, the second DM-RS for V2X communication being mapped in a second symbol in the first slot; generating a third DM-RS for V2X communication and a fourth DM-RS for V2X communication, the third DM-RS for V2X communication being mapped in a first symbol in a second slot of the subframe, the fourth DM-RS for V2X communication being mapped in a second symbol in the second slot; and transmitting the first DM-RS for V2X communication, the second DM-RS for V2X communication, the third DM-RS for V2X communication, and the fourth DM-RS for V2X communication. The first DM-RS is generated based on a first group-hopping, and the second DM-RS is generated based on a second group-hopping.

Abstract: Sidelink downlink control information (SL DCI) associated with transmission of one or more sidelink signals may be communicated. A wireless user device may transmit, based on the SL DCI and to one or more second wireless user devices, the one or more sidelink signals via a first quantity of sidelink channel resources. The wireless user device may receive first sidelink HARQ feedback information responsive to the one or more sidelink signals. The wireless user device may determine, based on a sidelink HARQ feedback timing, a time interval to transmit the first sidelink HARQ feedback information. The wireless user device may determine, based on the first quantity, a sidelink HARQ codebook. The wireless user device may transmit, during the time interval, based on the sidelink HARQ codebook, and to the base station, an uplink signal indicating the first sidelink HARQ feedback information.