Patent ID: 6633556
Filing Date: 2003-10-14
Classification: H04W

Abstract:
A mobile station apparatus of a CDMA system comprising:a radio communication system that is capable of communicating using at least a first frequency and a second frequency; a received quality measuring system that measures received qualities of signals of the first frequency and the second frequency transmitted from adjacent cells using respective spreading codes assigned to the cells to perform cell searching; and a frequency change system that determines a second base station apparatus as a destination of handover based on the received qualities, and change frequency according to a frequency changes instruction signal that instructs a change from the first frequency to the second frequency, when a movement direction of said mobile station apparatus is from a cell of a first base station apparatus that uses the first frequency and the second frequency and is communicating with said mobile station apparatus using the first frequency, to a cell of said second base station apparatus which communicates using the second frequency, wherein the movement direction is determined from a result obtained by measuring the received qualities of signals transmitted from the adjacent cells using the respective spreading codes assigned to the cells, and said mobile station apparatus performs a soft handover from the cell of said first base station apparatus to the cell of said second base station apparatus determined based on the received qualities in said received quality measuring system, after changing the frequency.