Abstract: A portable terminal and a method for originating a call through a substituted network when originating a call is barred due to overload of a first network is disclosed herein. A call may be originated by automatically switching the communication mode of the portable terminal from the first network such as an LTE network to a second network such as a 3G network or a 2G network, when originating a call is barred in the first network. The information of the cell of the second network is searched from a second network database stored in advance, which allows the time to search for a cell and time to register in the second network decrease. The searched cell with the highest power level may be selected and the call is originated through the selected cell of the second network.

Abstract: A portable terminal and a method for originating a call through a substituted network when originating a call is barred due to overload of a first network is disclosed herein. A call may be originated by automatically switching the communication mode of the portable terminal from the first network such as an LTE network to a second network such as a 3G network or a 2G network, when originating a call is barred in the first network. The information of the cell of the second network is searched from a second network database stored in advance, which allows the time to search for a cell and time to register in the second network decrease. The searched cell with the highest power level may be selected and the call is originated through the selected cell of the second network.

Abstract: The present invention relates to a method for a random access process in a mobile communication system. According to the exemplary embodiments, in the case where a mobile terminal requests a random access to a network, when the network is not able to promptly allocate a resource for the random access to the mobile terminal due to an insufficient resource, the mobile terminal is maintained in a standby state without repeatedly requesting the random access to the network. Accordingly, it is possible to reduce the uplink signal interference caused by the repeated random access request, reduce the possibility of communication contention between the mobile terminals for the access to the mobile communication system, and reduce the power consumption of the mobile terminal.