Methods, apparatuses, and systems are described for wireless communications. Cells may be grouped into a plurality of cell groups. A wireless device may receive one or more messages comprising configuration parameters of sounding reference signals. The wireless device may transmit, via a secondary cell of a secondary cell group, one or more of the sounding reference signals based on a timing advance.

In certain embodiments, a method of operating a wireless communication device comprises receiving a narrowband secondary synchronization signal (NSSS) in a discovery reference signal (DRS), identifying a transformation applied to the NSSS, and determining a DRS periodicity based on the identified transformation.

A downlink channel decoding method, a downlink information transmission method, a user equipment, and a base station are provided. The downlink channel decoding method includes: determining, by a user equipment, a resource unit occupied by a DMRS; and decoding a downlink channel based on the DMRS transmitted on the resource unit. The present invention can enable different DMRS patterns to concurrently exist on an NCT carrier. In a downlink transmission process, a DMRS pattern used for downlink transmission is determined according to priorities of different channels and/or signals, which can ensure optimal performance of a high-priority channel and/or signal, and can further improve downlink transmission performance.

One disclosure of this specification provides a method for receiving a synchronization signal block (SSB) by a user equipment (UE). The method may include: determining frequency locations of multiple SSBs; and receiving at least one SSB among the multiple SSBs. The multiple SSBs may be configured to be arranged spaced apart from each other by a predetermined offset. The at least one SSB may be located at an interval of 1.2 MHz on a frequency axis.

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.

A method of transmitting, by a first user equipment (UE), a sidelink synchronization signal to a second UE in a wireless communication system ay include determining values of N.sub.ID.sup.(1) and N.sub.ID.sup.(2) corresponding to a sidelink identifier (SLID) value based on a number of types of a physical layer sidelink synchronization identity set and a number of sequences included in each type of the physical layer sidelink synchronization identity set; generating a sidelink primary synchronization signal (PSS) sequence and a sidelink secondary synchronization signal (SSS) sequence based on a first primitive polynomial, a second primitive polynomial, and a cyclic shift (CS) value; and mapping, on physical resources, and thereby transmitting the sidelink PSS sequence and the sidelink SSS sequence.

According to an aspect of the present disclosure, a method includes receiving, by a user equipment (UE) from a first base station, on a first carrier, a synchronization sequence (SS) and performing a radio resource management (RRM) measurement in accordance with the SS. The method also includes performing cell selection and mobility support in accordance with the RRM measurement, when the UE is in idle mode and generating an RRM measurement report in accordance with the RRM measurement and transmitting, by the UE to the first base station on the first carrier, the RRM measurement report, when the UE is in connected mode.

Disclosed are a method, an apparatus, and a system for transmitting a signal using multiple carriers. In detail, provided are a wireless communication apparatus including a communication module; and a processor, wherein the processor obtains a common back-off counter for a carrier set on which data is to be transmitted, wherein the carrier set includes at least one component carrier, performs back-off of each of the component carriers using the obtained common back-off counter, and simultaneously transmits data through at least one component carrier in which the back-off is completed and a wireless communication method using the same.

Wireless communications for a plurality of cell groups are described. Uplink transmissions, such as uplink transport blocks, hybrid automatic repeat request (HARQ) transmission, and/or channel state information transmission, may be based on one or more time alignment timers associated with a cell group.

A method of transmitting an Orthogonal Frequency Division Multiplexing, OFDM, symbol having a guard interval including a cyclically repeated part of an original symbol comprises applying a guard interval for the OFDM symbol, the guard interval including a first part, where the first part is a cyclic prefix, including an indication whether the applied guard interval has a second part, wherein the second part is a cyclic prefix and/or postfix, applying, when indicated to be present, the second part of the guard interval, and transmitting the OFDM symbol. A method of receiving the symbol, transmitter, receiver and computer programs for implementing the methods are also disclosed.