A communication apparatus is provided. The communication apparatus comprises a radio transceiver module, a first subscriber identity card, a second subscriber identity card and a processor. The processor is coupled to the radio transceiver module, the first subscriber identity card and the second subscriber identity card, determines a first paging parameter for the first subscriber identity card, obtains second paging parameters from a second cell belonging to a second wireless network for the second subscriber identity card, determines one from the obtained second paging parameters with consideration of the determined first paging parameter, and transmits the determined second paging parameter via the radio transceiver module to the second wireless network through the second cell, thereby enabling the second cell to broadcast paging messages periodically by a time period based on the determined second paging parameter.