Abstract: A system and a method for canceling an echo is disclosed. In accordance with the system and the method, a plurality of independently and variably delayed adaptive algorithm blocks are selectively applied to a delayed feedback signal to generate a plurality of echo components in parallel, thereby canceling the echo component from an input signal.

Abstract: Provided is a link synchronization method for a radio frequency repeater that can perform link route switching at an accurate time point by measuring reception signal power at a predetermined period for a predetermined time duration, accumulating and comparing them with a reference level, and detecting a link termination time point. The method includes: a) setting up an initial link route; b) measuring received signal power in the initial link route; c) accumulating the reception signal power received for a predetermined time at a predetermined period, when the reception signal power is detected; d) setting up a reference level for link switching based on the accumulated reception signal power; e) detecting a link termination time point by finding an edge in a waveform of the accumulated reception signal power based on the reference level; and f) switching the current link route based on the detected link termination time point.

Abstract: Provided is a link synchronization method for a radio frequency repeater that can perform link route switching at an accurate time point by measuring reception signal power at a predetermined period for a predetermined time duration, accumulating and comparing them with a reference level, and detecting a link termination time point. The method includes: a) setting up an initial link route; b) measuring received signal power in the initial link route; c) accumulating the reception signal power received for a predetermined time at a predetermined period, when the reception signal power is detected; d) setting up a reference level for link switching based on the accumulated reception signal power; e) detecting a link termination time point by finding an edge in a waveform of the accumulated reception signal power based on the reference level; and f) switching the current link route based on the detected link termination time point.

Abstract: Capacity enhancement schemes are described for forward and reverse links of distributed cellular base stations consisting of a central unit and one or more remote units. In general, in one aspect, reverse link capacity is shared among remote units. The capacity sharing can be determined dynamically. The forward link capacity can also be enhanced by estimating the location of the mobile stations.

Abstract: A device for compensating for the nonlinearity of a power amplifier which has a simple configuration and can precisely linearize the transfer characteristics of the power amplifier by predistorting an input signal of the power amplifier. The nonlinearity compensation device of the present invention converts an RF input signal into an IF band rather than a baseband and predistorts the RF input signal in digital domain, and thus any modulation or demodulation process is obviated and the simultaneous processing of signals in multiple channels is facilitated. A first downconverter receives the RF input signal and converts the frequency band of the signal into the IF band to output an IF input signal. A predistortion unit receives and predistorts the IF input signal to compensate for the nonlinearity, and outputs an IF predistorted signal. An upconverter converts the frequency band of the IF predistorted signal into the RF band to provide such a signal to the amplifier.

Abstract: A device for compensating for the nonlinearity of a power amplifier which has a simple configuration and can precisely linearize the transfer characteristics of the power amplifier by predistorting an input signal of the power amplifier. The nonlinearity compensation device of the present invention converts an RF input signal into an IF band rather than a baseband and predistorts the RF input signal in digital domain, and thus any modulation or demodulation process is obviated and the simultaneous processing of signals in multiple channels is facilitated. A first downconverter receives the RF input signal and converts the frequency band of the signal into the IF band to output an IF input signal. A predistortion unit receives and predistorts the IF input signal to compensate for the nonlinearity, and outputs an IF predistorted signal. An upconverter converts the frequency band of the IF predistorted signal into the RF band to provide such a signal to the amplifier.