A method of controlling a dual mode mobile terminal, and which includes receiving, via a wireless communication unit of the mobile terminal, synchronous time information from a first communication network, the synchronous time information being used for a system time of the mobile terminal and for system time synchronization of the mobile terminal with the first communication network; receiving, via the wireless communication unit, asynchronous time information from a second communication network, the asynchronous time information not being used for system time synchronization of the mobile terminal with the second communication network; calculating, via the controller, an average of a calculated difference between the synchronous time information and the asynchronous time information; receiving, via the wireless communication unit, a message from the second communication network; and setting, via the controller, a reception time stamp of when the message is received based on time information contained in the message received from the second communication network and the calculated average difference.