A method by which a terminal transmits a discovery signal for device-to-device communication in a wireless communication system is disclosed in the present application. Particularly, the method comprises the steps of: receiving one or more downlink signals; determining transmission power for transmitting the discovery signal on the basis of reference reception power of the one or more downlink signals; and transmitting the discovery signal on the basis of the determined transmission power, wherein the transmission power decreases as the reference reception power increases.

A method and system for setting a power of a secondary device-to-device synchronization signal, SD2DSS, by a first wireless device to enable a second wireless device to synchronize timing of the second wireless device to a timing of the first wireless device are disclosed. According to one aspect, a method includes determining power of a first signal transmitted by the first wireless device, and setting the power of the SD2DSS based on the power of the first signal.

Provided are a method and apparatus for data transmission link maintenance, and a method and apparatus for triggering maintenance. The method for data transmission link maintenance includes: establishing a sidelink for transmitting vehicle-to-everything (V2X) service data, and performing communication between a first user equipment (UE) and a second UE over the sidelink; obtaining a first pathloss; obtaining a second pathloss; and maintaining a V2X transmission link when a relationship between the first pathloss and the second pathloss meets a trigger condition. The method for triggering maintenance includes: establishing a sidelink; obtaining a first pathloss; obtaining a second pathloss; and triggering maintenance of a V2X transmission link when a relationship between the first pathloss and the second pathloss meets a trigger condition.

In one aspect, a method of wireless communication includes receiving, by a user equipment (UE), a downlink control signaling scheduling one or more uplink transmissions for one or more transmission resources. The method also includes determining, by the UE, to perform superposition transmission operations for at least one transmission resource of the one or more transmission resources. The method further includes transmitting, by the UE, an uplink channel data transmission and a sidelink channel data transmission in a same transmission resource, responsive to determining to perform superposition transmission operations for the least one transmission resource. Other aspects are described and claimed.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a configuration for sidelink feedback power control. The UE may transmit a sidelink feedback transmission, in accordance with the configuration, using a transmit power that is based at least in part on at least one of: a quantity of resource blocks (RBs) associated with the sidelink feedback transmission, a quantity of symbols associated with the sidelink feedback transmission, a sidelink pathloss value, or a size of the sidelink feedback transmission. Numerous other aspects are provided.

The disclosure relates to a communication technique for convergence between an IoT technology and a 5.sup.th generation (5G) communication system for supporting a higher data transmission rate than a 4.sup.th generation (4G) system, and a system thereof. The disclosure may be applied to intelligence services (for example, smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail businesses, security and safety related services, etc.) on the basis of a 5G communication technology and an IoT-related technology. The disclosure provides a method and an apparatus for determining transmission power for transmission of an uplink signal and/or channel or a sidelink signal and/or channel, which is applied in an unlicensed band.

The present disclosure relates to a method for transmitting and receiving a device-to-device (D2D) signal in a wireless communication system supporting D2D communication, said method, performed by a terminal, comprising the steps of: transmitting a cellular signal on a first subframe of a first component carrier; transmitting a D2D signal on a second subframe of a second component carrier; and when overlapping occurs between the first subframe and the second subframe, dropping the transmission of the D2D signal or reducing transmit power of the D2D signal in a specific interval.

An embodiment of the present invention relates to a method for transmitting a synchronization signal in a wireless communication system, the method comprising the steps of: generating a synchronization signal on the basis of a cell ID which is determined depending on whether a terminal for transmitting the synchronization signal is a terminal located outside of a coverage; and transmitting the synchronization signal.

The present invention relates to a 5G or pre-5G communication system which is to be provided to support high data throughput beyond a 4G communication system such as LTE. The communication method for a terminal in a wireless communication system supporting carrier aggregation according to the present invention comprises the steps of: confirming data transmission between different carriers is carried out on the basis of cellular and device-to-device (D2D) communication; reducing the transmission power for a D2D communication-based data transmission to a configured value; and, if no cellular communication-based data transmission occurs during a set time, then restoring the reduced transmission power for the D2D communication-based data transmission.

A communication method and an apparatus are provided. The method includes: obtaining, by a base station, power parameters of a first user equipment UE and an adjustment parameter δ.sub.1,ue1 for a first transmit power; sending, by the base station, the power parameters of the first UE and the adjustment parameter δ.sub.1,ue1 for the first transmit power to the first UE; determining, by the base station, the first transmit power according to the power parameters of the first UE and the adjustment parameter δ.sub.1,ue1 for the first transmit power; and sending, by the base station, a signal to the first UE at the first transmit power.