A paging channel is monitored at a special position of every predetermined time interval subsequent to the last monitored time. It is detected whether a same first identity information is repeatedly broadcasted in the paging channel at special positions of different predetermined time interval. A total number of periodically repeated messages containing the same first identity information is determined. A new time interval is determined by multiplying a time period between two successive repeated paging messages with the total number of periodically repeated paging messages, wherein the new time interval has a monitoring interval (having a plurality of predetermined time intervals) equaling to the length of the time period and a sleep interval. The paging channel is monitored at special positions of the plurality of predetermined time intervals in every new time interval subsequent to the last monitored time so as to receive subsequent paging messages from the cell.