A user equipment for controlling transmission in a wireless communication system, comprising: a memory; a transceiver; and a processor coupled to the memory and the transceiver, wherein the processor is configured to implement an access stratum layer to: receive, from an upper layer to the AS layer, a first indication and a second indication for a packet, wherein the first indication is configured to indicate whether to perform a packet data control protocol (PDCP) duplication, and the second indication is configured to indicate whether to use features of sidelink technology developed under 3GPP release 15; control the AS layer not to perform the PDCP duplication and control the AS layer not to use the features of sidelink technology developed under 3GPP release 15 when the first indication indicates to perform the PDCP duplication and the second indication indicates not to use the features of sidelink technology developed under 3GPP release 15; and when the second indication indicates to use the features of sidelink technology developed under 3GPP release 15, the second indication indicates to use a release 15 format comprising using rate matching, transport block size scaling, and/or a modulation and coding scheme table supporting a 64 quadrature amplitude modulation to transmit a corresponding V2X packet. a memory; a transceiver; and a processor coupled to the memory and the transceiver, wherein the processor is configured to implement an access stratum layer to: receive, from an upper layer to the AS layer, a first indication and a second indication for a packet, wherein the first indication is configured to indicate whether to perform a packet data control protocol (PDCP) duplication, and the second indication is configured to indicate whether to use features of sidelink technology developed under 3GPP release 15; control the AS layer not to perform the PDCP duplication and control the AS layer not to use the features of sidelink technology developed under 3GPP release 15 when the first indication indicates to perform the PDCP duplication and the second indication indicates not to use the features of sidelink technology developed under 3GPP release 15; and when the second indication indicates to use the features of sidelink technology developed under 3GPP release 15, the second indication indicates to use a release 15 format comprising using rate matching, transport block size scaling, and/or a modulation and coding scheme table supporting a 64 quadrature amplitude modulation to transmit a corresponding V2X packet. receive, from an upper layer to the AS layer, a first indication and a second indication for a packet, wherein the first indication is configured to indicate whether to perform a packet data control protocol (PDCP) duplication, and the second indication is configured to indicate whether to use features of sidelink technology developed under 3GPP release 15; control the AS layer not to perform the PDCP duplication and control the AS layer not to use the features of sidelink technology developed under 3GPP release 15 when the first indication indicates to perform the PDCP duplication and the second indication indicates not to use the features of sidelink technology developed under 3GPP release 15; and when the second indication indicates to use the features of sidelink technology developed under 3GPP release 15, the second indication indicates to use a release 15 format comprising using rate matching, transport block size scaling, and/or a modulation and coding scheme table supporting a 64 quadrature amplitude modulation to transmit a corresponding V2X packet.