Abstract: A method is provided for transmitting a signal in a signal transmission apparatus of a communication system. Upon receiving a signal, the signal transmission apparatus determines a mode of the received signal, in which a power amplifier should amplify the signal; generates a mode control signal corresponding to a single mode, if the mode of the received signal is determined as the single mode; amplifies and transmits the received signal in the single mode according to the mode control signal; generates a mode control signal corresponding to a multi-mode, if the mode of the received signal is the multi-mode; and amplifies and transmits the received signal in the multi-mode according to the mode control signal.

Abstract: An apparatus and method for controlling a digital AGC in a communication system in which power changes significantly from frame to frame. In the digital AGC controlling apparatus, an SNR estimator estimates an uplink SNR of a next frame. A power measurer measures uplink received power of every frame. A gain calculator estimates uplink power of an nth frame using an SNR estimate of an (n?1)th frame received from the SNR estimator and a received power measurement of the (n?1)th frame received from the power measurer, and calculates a gain to be applied to the nth frame in the digital AGC using the uplink power estimate of the nth frame.

Abstract: A method is provided for transmitting a signal in a signal transmission apparatus of a communication system. Upon receiving a signal, the signal transmission apparatus determines a mode of the received signal, in which a power amplifier should amplify the signal; generates a mode control signal corresponding to a single mode, if the mode of the received signal is determined as the single mode; amplifies and transmits the received signal in the single mode according to the mode control signal; generates a mode control signal corresponding to a multi-mode, if the mode of the received signal is the multi-mode; and amplifies and transmits the received signal in the multi-mode according to the mode control signal.

Abstract: A base station power amplifier for minimizing memory effect is provided. The power amplifier includes a bias circuit which supplies a direct current (DC) power to a transistor; the transistor which amplifies the DC power provided from the bias circuit; a matching circuit which transfers maximum power to a load by reducing loss of the power amplified by the transistor; and a large capacitor which lies between the matching circuit and the transistor, reduces a low-frequency second harmonic voltage by electrically connecting directly to the matching circuit, and has a preset capacitance value.

Abstract: Provided is a method for determining handover of a mobile station by a serving base station in a mobile communication system. The method includes receiving traffic quality information from the mobile station; determining whether the traffic quality information satisfies a preset setting condition; if the traffic quality information satisfies the setting condition, sending a request for pilot signal strength measurement for the serving base station and adjacent base stations to the mobile station; receiving pilot signal strengths of the base stations, reported by the mobile station; determining whether there is a corresponding base station whose pilot signal strength exceeds the pilot signal strength of the serving base station; and determining handover of the mobile station to the corresponding base station.

Abstract: An apparatus and method for controlling a digital AGC in a communication system in which power changes significantly from frame to frame. In the digital AGC controlling apparatus, an SNR estimator estimates an uplink SNR of a next frame. A power measurer measures uplink received power of every frame. A gain calculator estimates uplink power of an nth frame using an SNR estimate of an (n?1)th frame received from the SNR estimator and a received power measurement of the (n?1)th frame received from the power measurer, and calculates a gain to be applied to the nth frame in the digital AGC using the uplink power estimate of the nth frame.