An apparatus for a user terminal comprising: a processor and a memory, the processor configured to cause the user terminal to receive from a base station that manages a serving cell of the user terminal, a first SIB indicating a D2D frequency list in a second PLMN different from a first PLMN in which the serving cell is included; receive a second SIB from a cell in the second PLMN; acquire setting information including discovery resource information by decoding the second SIB; determine a first transmission gap used to transmit a discovery signal in a first frequency included in the D2D frequency list in the second PLMN, the discovery signal being a direct terminal-to-terminal radio signal for discovering another user terminal; transmit a message to the base station, the message requesting the first transmission gap, and receive configuration information from the base station, the configuration information configuring the first transmission gap to the user terminal, wherein the message includes: first gap information indicating the first transmission gap; and fist frequency information indicating the first frequency associated with the gap information, the first gap information includes: a bitmap indicating at least one subframe requested by the user terminal as the first transmission gap; and an offset value with reference to "0" of a system frame number, SFN, the processor is further configured to cause the user terminal to transmit the discovery signal during the first transmission gap, and prioritize transmission of a uplink signal to the base station over transmission of the discovery signal during the first transmission gap, when receiving an UL grant from the base station indicating transmission of the uplink signal. a processor and a memory, the processor configured to cause the user terminal to receive from a base station that manages a serving cell of the user terminal, a first SIB indicating a D2D frequency list in a second PLMN different from a first PLMN in which the serving cell is included; receive a second SIB from a cell in the second PLMN; acquire setting information including discovery resource information by decoding the second SIB; determine a first transmission gap used to transmit a discovery signal in a first frequency included in the D2D frequency list in the second PLMN, the discovery signal being a direct terminal-to-terminal radio signal for discovering another user terminal; transmit a message to the base station, the message requesting the first transmission gap, and receive configuration information from the base station, the configuration information configuring the first transmission gap to the user terminal, wherein receive from a base station that manages a serving cell of the user terminal, a first SIB indicating a D2D frequency list in a second PLMN different from a first PLMN in which the serving cell is included; receive a second SIB from a cell in the second PLMN; acquire setting information including discovery resource information by decoding the second SIB; determine a first transmission gap used to transmit a discovery signal in a first frequency included in the D2D frequency list in the second PLMN, the discovery signal being a direct terminal-to-terminal radio signal for discovering another user terminal; transmit a message to the base station, the message requesting the first transmission gap, and receive configuration information from the base station, the configuration information configuring the first transmission gap to the user terminal, wherein the message includes: first gap information indicating the first transmission gap; and fist frequency information indicating the first frequency associated with the gap information, the first gap information includes: a bitmap indicating at least one subframe requested by the user terminal as the first transmission gap; and an offset value with reference to "0" of a system frame number, SFN, a bitmap indicating at least one subframe requested by the user terminal as the first transmission gap; and an offset value with reference to "0" of a system frame number, SFN, the processor is further configured to cause the user terminal to transmit the discovery signal during the first transmission gap, and prioritize transmission of a uplink signal to the base station over transmission of the discovery signal during the first transmission gap, when receiving an UL grant from the base station indicating transmission of the uplink signal. transmit the discovery signal during the first transmission gap, and prioritize transmission of a uplink signal to the base station over transmission of the discovery signal during the first transmission gap, when receiving an UL grant from the base station indicating transmission of the uplink signal.