A disclosure of the present specification provides a method for receiving a sidelink synchronisation signal (SLSS) for proximity service (ProSe). The method may comprise the steps of: receiving an SLSS from a neighbouring ProSe UE; and measuring a reference signal received power (RSRP) of the SLSS during a pre-determined measurement period. The measurement step can be executed assuming that the SLSS transmission from the neighbouring ProSe UE during the measurement period is not abandoned more than once. The measurement period can be extended if the SLSS transmission from the neighbouring ProSe UE is abandoned more than once.