| 摘要 |
PURPOSE: A method and a system for preventing a call drop by limiting search time of a 1x system during 1x EV-DO traffic state are provided to prevent an undesired call drop by enabling an HAT(Hybrid Access Terminal) to return to the 1xEV-DO system before the call drop. CONSTITUTION: A HAT initializes 1x mode and then an EV-DO mode to maintain a standby state(S500). The HAT performs a dual monitoring between the 1x mode and the EV-DO mode(S502). If data is transmitted from a 1xEV-DO transmitter or a user of the HAT requests data from a 1xEV-DO system, the HAT determines whether to be activated in an EV-DO mode to enter into a traffic state(S504). If the HAT enters into the traffic state of the 1xEV-DO mode, it transmits and receives packet data to and from an 1xEV-DO system(S506). The HAT drives a timer to check whether it reaches a pre-set monitoring period(S508). If the timer reaches the pre-set monitoring period, the HAT is switched to a 1x system to start searching an overhead message in the 1x system(S510). The HAT checks a search time, searches the 1x system, receives and demodulates the overhead message(S512). The HAT continuously checks whether the timer reaches a pre-set search time(S514). If the timer reaches the pre-set search time, the HAT stores the previously received overhead message in a memory and returns to the 1xEV-DO system(S516).
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