Siemens Aktiengesellschaft

Palm, Incorporated

Theo Kreul

Andreas Falkenberg

Bernd Bienek

Holger Landenberger

Stephan Karger

Albrecht Kunz

A method is provided for frequency acquisition, particularly for initial frequency acquisition, pursuant to a known synchronization sequence for synchronizing a mobile communications device having a local oscillator with previously known transmit frequencies of a base station that transmit in a known channel raster with defined frequency points within a band, wherein the method includes the steps of determining the inband power of the known synchronization sequence via a sensor by scanning a frequency band, performing coarse determination of the local power maximum of the inband power and, thus, of the received carrier frequency over the scanned frequency band, producing a presumed channel frequency at which the base station is transmitting on the basis of knowledge of the channel raster of the transmit frequencies of the base station, performing fine determination of the received carrier frequency by comparison with the known synchronization sequence, and correcting the frequency deviation of the local oscillator from the transmitted carrier frequency.

Method for frequency acquisition of a mobile communications device

A method is provided for calibrating the frequency of an RF oscillator in a mobile part of a mobile communications device when the mobile part is first switched on, wherein the method includes the steps of: sampling a modulated carrier that is transmitted by a base station and has a prescribed frequency accuracy, such that scanning of the modulated carrier is performed via a frequency search algorithm with the modulated carrier being demodulated, a signal thus demodulated being compared in an evaluation and synchronization program via a correlation with a sequence known in advance, and a correlation peak in an output of the correlator being determined; determining a frequency error between the frequency of the RF oscillator in the mobile part of the mobile communications device and a known channel frequency of the base station by comparing the determined correlation peak of the output of the correlator with a channel raster, known in advance to the mobile communications device, of the base station; synchronizing the mobile communications device with the modulated carrier; and adopting a frequency, corrected by the frequency error, for the RF oscillator as reference frequency for further calibration operations.

Method for calibrating the frequency of an RF oscillator in a mobile part of a mobile communications device

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Coesfeld-Lette, Germany

Theo Kreul