The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for receiving handover assistance information including a list of one or more candidate target cells; initiating a first random access procedure to a first candidate target cell of the one or more candidate target cells and a first timer for the first candidate target cell, when the first candidate target cell satisfies a handover condition; and stopping trying to connect to the first candidate target cell when any one of at least the following events occurs: (i) the first timer expires for the first candidate target cell, and (ii) a number of random access trials to the first candidate target cell reaches a maximum number.