The present invention relates to a system for enabling a communication function of a device, and a method for communicating by a terminal, according to one embodiment of the present invention, comprises the steps of: transmitting, to an MME, an attach request message including a public safety indication and/or a group communication indication; receiving, from the MME, an attach accept message including at least one type of information from among a ProSe identifier, a ProSe group identifier, and a ProSe group for performing a ProSe, ProSe-related functions of the terminal, and a proximity-related security key (ProSe key); transmitting a ProSe registration request to a ProSe function server; and receiving, from the ProSe function server, a ProSe registration response message pending authentication of the terminal. According to one embodiment of the present invention, devices can mutually provide or receive information within a group in an environment such as an EUTRAN or a UTRAN/GERAN.