Method and apparatus for performing inter-carrier D2D communication

A base station for providing discovery resource pool information to one or more user equipments (UEs) on a first carrier, the base station comprising:

• a transceiver;
• and
• at least one processor coupled to the transceiver and configured to:
• identify information among first information, second information, third information and fourth information, for a second carrier among a plurality of carriers;
• and
• transmit system information including carrier frequency information of the second carrier, wherein the carrier frequency information of the second carrier includes the identified information for the second carrier,
• wherein the first information includes discovery resource pool information of the second carrier,
• wherein the second information indicates to obtain the discovery resource pool information of the second carrier by reading a system information block (SIB) transmitted on the second carrier,
• wherein the third information indicates to obtain the discovery resource pool information of the second carrier by requesting the base station on the first carrier, and
• wherein the fourth information indicates not to transmit a discovery message on the second carrier.

A method, performed by a user equipment (UE) in a radio resource control (RRC) idle state served by a base station on a first carrier, for obtaining discovery resource pool information, the method comprising:

• receiving, from the base station, system information including carrier frequency information of a second carrier, wherein the carrier frequency information of the second carrier includes information among first information, second information, third information and fourth information for the second carrier among a plurality of carriers;
• and
• identifying the information for the second carrier,
• wherein the first information includes discovery resource pool information of the second carrier,
• wherein the second information indicates to obtain the discovery resource pool information of the second carrier by reading a system information block (SIB) transmitted on the second carrier,
• wherein the third information indicates to obtain the discovery resource pool information of the second carrier by requesting the base station on the first carrier, and
• wherein the fourth information indicates not to transmit a discovery message on the second carrier.

A user equipment (UE) in a radio resource control (RRC) idle state, served by a base station on a first carrier for obtaining discovery resource pool information, the UE comprising:

• a transceiver;
• and
• at least one processor coupled to the transceiver and configured to:
• receive, from the base station, system information including carrier frequency information of a second carrier, wherein the carrier frequency information of the second carrier includes information among first information, second information, third information and fourth information for the second carrier among a plurality of carriers;
• and
• identify the information for the second carrier,
• wherein the first information includes discovery resource pool information of the second carrier,
• wherein the second information indicates to obtain the discovery resource pool information of the second carrier by reading a system information block (SIB) transmitted on the second carrier,
• wherein the third information indicates to obtain the discovery resource pool information of the second carrier by requesting the base station on the first carrier, and
• wherein the fourth information indicates not to transmit a discovery message on the second carrier.