determines that ue has data on which prose direct communication will be performed and requires a resource for the transmission of the data based on the prose bsr mode 2 is mode in which ue directly selects a resource ue directly selects a resource for prose direct communication in a resource pool the resource pool may be configured by a network or may be previously determined meanwhile if ue has a serving cell that is if the ue is in the rrc_connected state with an enb or the ue in the rrc_idle state is placed in a specific cell the ue is considered to be placed within coverage of the enb if ue is placed outside coverage only mode 2 may be applied if the ue is placed within coverage the ue may use mode 1 or mode 2 depending on a configuration of an enb if another exception condition is not present only when an enb performs a configuration ue may change its mode from mode 1 to mode 2 or from mode 2 to mode 1 prose direct discovery refers to a procedure used by prose enabled ue in order to discover another proximity prose enabled ue and is also called d2d direct discovery in this case e utra radio signals through the pc 5 interface may be used information used in the prose direct discovery is hereinafter called discovery information fig7 shows the pc 5 interface for d2d direct discovery referring to fig7 the pc 5 interface includes an mac layer a phy layer and a prose protocol layer that is a higher layer the permission of the announcement and monitoring of discovery information is handled by the higher layer the prose protocol the contents of discovery information are transparent to an access stratum.