A method for controlling an operation of a mobile communication terminal for providing a high-speed data rate (HDR) service. The mobile communication terminal comprises first and second antennas, a first radio frequency (RF) module connected to the first antenna and having an RF transmitter and an RF receiver, and a second RF module connected to the second antenna and having a dedicated RF receiver If a current mode of the mobile communication terminal is a traffic mode for providing the HDR service, battery power is supplied to both the first and second RF modules and signal processing associated with the first and second RF modules is performed. If the current mode of the mobile communication terminal is not the traffic mode for providing the HDR service, a supply of the battery power is blocked to the second RF module and the signal processing associated with the first RF module is performed. Rates of high-speed data received through the first and second antennas are periodically checked while the mobile communication terminal is in the traffic mode. If a current one of the high-speed data rates is higher than a predetermined threshold value, the supply of the battery power is blocked to the second RF module and the signal process associated with the first RF module is performed.