of the perch channel is carried out simultaneously with the reception of the paging signal this makes it possible to save the power consumption with maintaining the high accuracy of selecting the best base station furthermore the embodiment is configured such that it counts the elapsed time from the measurement of the receiving quality of the perch channel and when the elapsed time exceeds the predetermined value it carries out the measurement of the receiving quality of the perch channel this makes it possible to maintain the accuracy of selecting the best base station at a higher accuracy making is possible to further reduce the power consumption as to the standards of the third generation mobile communication system imt 2000 international mobile telecommunications 2000 the 3gpp third generation partnership project is making a plan details of paging information transmission method is described in the standard u201c 3gts 25 211 v3 3 0 u201d to increase the versatility of the standard it is modified slightly from the u201c japan 39 s revised proposal for candidate radio transmission technology on imt 2000 w cdma u201d specifically it is configured such that the information about the presence and absence of the paging is transmitted over a pich paging indicator channel and the paging information itself is transmitted over an sccpch secondary common control physical channel although the physical configuration is thus modified the standard is the same as the present specification in the procedure for the mobile station to receive the pi portion before receiving the paging information and to.