1. A method for performing a random access procedure in an unlicensed band, the method comprising:performing, by a wireless device, a clear channel assessment (CCA) during a random access preamble (RAP) window in the unlicensed band; and
transmitting, by the wireless device, a plurality of RAPs if the CCA is successful,
wherein the plurality of RAPs are repeatedly transmitted in a frequency domain or a time domain, and
wherein the plurality of RAPs include a first RAP transmitted in a first frequency band within the unlicensed band and a second RAP transmitted in a second frequency band within the unlicensed band, and the first RAP and the second RAP are transmitted at a same time point.