A user terminal operating a transmission protocol for uplink data packet transmission in a communication system, wherein a transmission counter is configured for the transmission protocol of the user terminal for counting the number of transmissions the user terminal has performed for a data packet, wherein the user terminal is configured to participate in sidelink discovery operation with other user terminals based on sidelink discovery gaps configured for the user terminal, wherein the user terminal cannot transmit and/or receive signals under control of the transmission protocol when participating in sidelink discovery operation during the sidelink discovery gaps, wherein the user terminal comprises: a processor configured to determine whether a retransmission of a data packet, whichis triggered by the transmission protocol, was not performed because the transmission protocol operation collided with one of the sidelink discovery gaps, in case of collision, the processor being further configured to operate the transmission counter such that the colliding retransmission of the data packet does not result in an increment of the transmission counter of the transmission protocol for the data packet, and wherein the user terminal is configured with a sidelink discovery gap for reception, during which the user terminal monitors for sidelink discovery messages transmitted from other user terminals via a sidelink connection, wherein the processor determines that the retransmission of the data packet was not performed because the transmission protocol operation collided with one of the sidelink discovery gaps, when: feedback of the transmission protocol relating to a previous transmission of the data packet is not received, because of colliding with the sidelink discovery gap for reception, wherein the transmission protocol provides for the step of incrementing the transmission counter of the transmission protocol by 1 when the retransmission is triggered by the transmission protocol, and wherein the processor is configured to operate the transmission protocol such that the colliding retransmission of the data packet does not result in an increment of the transmission counter for the data packet, by: the processor being configured to not perform the step of incrementing the transmission counter by 1 when the retransmission is triggered by the transmission protocol, in case of collision, or the processor being configured to perform the step of incrementing the transmission counter of the transmission protocol by 1 when the retransmission is triggered by the transmission protocol, and the processor being configured to subsequently perform a step of decreasing the transmission counter by 1, in case of collision. a processor configured to determine whether a retransmission of a data packet, whichis triggered by the transmission protocol, was not performed because the transmission protocol operation collided with one of the sidelink discovery gaps, in case of collision, the processor being further configured to operate the transmission counter such that the colliding retransmission of the data packet does not result in an increment of the transmission counter of the transmission protocol for the data packet, and wherein the user terminal is configured with a sidelink discovery gap for reception, during which the user terminal monitors for sidelink discovery messages transmitted from other user terminals via a sidelink connection, wherein the processor determines that the retransmission of the data packet was not performed because the transmission protocol operation collided with one of the sidelink discovery gaps, when: feedback of the transmission protocol relating to a previous transmission of the data packet is not received, because of colliding with the sidelink discovery gap for reception, wherein the transmission protocol provides for the step of incrementing the transmission counter of the transmission protocol by 1 when the retransmission is triggered by the transmission protocol, and wherein the processor is configured to operate the transmission protocol such that the colliding retransmission of the data packet does not result in an increment of the transmission counter for the data packet, by: the processor being configured to not perform the step of incrementing the transmission counter by 1 when the retransmission is triggered by the transmission protocol, in case of collision, or the processor being configured to perform the step of incrementing the transmission counter of the transmission protocol by 1 when the retransmission is triggered by the transmission protocol, and the processor being configured to subsequently perform a step of decreasing the transmission counter by 1, in case of collision. the processor being configured to not perform the step of incrementing the transmission counter by 1 when the retransmission is triggered by the transmission protocol, in case of collision, or the processor being configured to perform the step of incrementing the transmission counter of the transmission protocol by 1 when the retransmission is triggered by the transmission protocol, and the processor being configured to subsequently perform a step of decreasing the transmission counter by 1, in case of collision.