Abstract: Provided is an apparatus and method for saving power in a dual mode portable terminal that concurrently supports a cellular network and an unlicensed band network. The method includes, upon disassociating from an in-association Access Point (AP) of an unlicensed band network, measuring a Received Signal Strength Indicator (RSSI) from the AP during a predetermined time and calculating an average value of the RSSI; and comparing the calculated average value with a predetermined threshold value and deciding whether to perform a mode conversion between a low power mode and a general mode.

Abstract: A method and apparatus for connection an emergency call in a dual mode portable terminal supporting both a cellular network and an unlicensed-band network using an unlicensed Industrial, Science, and Medical (ISM) frequency band (e.g., WiFi, Bluetooth, UWB, etc.) are provided. The method includes if an emergency call connection event occurs, searching for an accessible network and checking an insertion state of a SIM card; if the unlicensed-band network is accessible and the SIM card is not inserted, performing an IP-based Multimedia Subsystem (IMS) registration process by using information pre-stored in a memory; and connecting the emergency call through the unlicensed-band network.

Abstract: Provided is an apparatus and method for saving power in a dual mode portable terminal that concurrently supports a cellular network and an unlicensed band network. The method includes, upon disassociating from an in-association Access Point (AP) of an unlicensed band network, measuring a Received Signal Strength Indicator (RSSI) from the AP during a predetermined time and calculating an average value of the RSSI; and comparing the calculated average value with a predetermined threshold value and deciding whether to perform a mode conversion between a low power mode and a general mode.