During the determination that is performed at least according to the service type and the data traffic size included in the data, the table of service types may be preset in the UE. The table includes a mapping relationship between the service type and the data traffic. When the UE needs to send or receive data, the UE determines whether the service type included in the data may be found in the table of service types. If the service type is found in the table of service types, the UE continues to determine whether the data traffic of the data to be sent or received is larger than or equal to the data value corresponding to the service type of the data to be sent or received in the table of service types. If the data traffic to be sent or received is larger than or equal to the data value corresponding to the service type of the data to be sent or received in the table of service types, the LTE radio frequency unit is turned on, so as to make the PS domain of the UE camp on the LTE network.

It should be noted that, in the embodiment of the present invention, whether the service type and the data traffic size included in the data need to be determined and specific determination manners are determined according to practical cases, which are not limited here.

It should be noted that, in the embodiment of the present invention, if the UE does not need to send or receive data, or the data sent or received by the UE does not meet the preset condition, the UE stays in the state in which the CS domain and the PS domain both camp on the 2G/3G network, where that the data sent or received by the UE does not meet the preset condition may be that the data traffic size of the sent or received data is smaller than the a preset value, or that the service type of the data is not a service type needing to use an LTE network.