A method performed by a second user equipment, UE, in a wireless communication system, the method comprising: receiving a device-to-device, D2D, synchronization signal, SS, from a first UE; receiving a first scheduling assignment, SA, which informs transmission of first D2D related control information for assigned D2D resource from the first UE, wherein the first SA includes D2D specific frame number for the first D2D related control information, from the first UE; receiving the first D2D related control information based on the first SA, wherein the first D2D related control information includes D2D modification period configuration, D2D repetition period configuration, SA configuration and D2D radio bearer, RB, configuration set; if there is D2D data to be transmitted in D2D buffer, deciding to perform transmission of the D2D data; transmitting a second SA which informs transmission of the second D2D related control information for assigned D2D resource from the second UE, to the first UE and a third UE; transmitting the second D2D related control information to the first UE and the third UE periodically, based on the D2D modification period configuration and the D2D repetition period configuration; transmitting a third SA to assign D2D resource for transmission of the D2D data, to the first UE and the third UE; and transmitting the D2D data based on the third SA, to the first UE and the third UE, wherein the first UE is a D2D synchronization reference UE, wherein the first D2D related control information is transmitted via a D2D control channel defined on a direct interface between the first UE and the second UE, wherein the second D2D related control information is transmitted via a D2D control channel defined on a direct interface between the second UE and the third UE. receiving a device-to-device, D2D, synchronization signal, SS, from a first UE; receiving a first scheduling assignment, SA, which informs transmission of first D2D related control information for assigned D2D resource from the first UE, wherein the first SA includes D2D specific frame number for the first D2D related control information, from the first UE; receiving the first D2D related control information based on the first SA, wherein the first D2D related control information includes D2D modification period configuration, D2D repetition period configuration, SA configuration and D2D radio bearer, RB, configuration set; if there is D2D data to be transmitted in D2D buffer, deciding to perform transmission of the D2D data; transmitting a second SA which informs transmission of the second D2D related control information for assigned D2D resource from the second UE, to the first UE and a third UE; transmitting the second D2D related control information to the first UE and the third UE periodically, based on the D2D modification period configuration and the D2D repetition period configuration; transmitting a third SA to assign D2D resource for transmission of the D2D data, to the first UE and the third UE; and transmitting the D2D data based on the third SA, to the first UE and the third UE, wherein the first UE is a D2D synchronization reference UE, wherein the first D2D related control information is transmitted via a D2D control channel defined on a direct interface between the first UE and the second UE, wherein the second D2D related control information is transmitted via a D2D control channel defined on a direct interface between the second UE and the third UE.