Siemens Aktiengesellschaft

Gigaset Communications Gmbh

Arca Beteiligungen Gmbh

Ralf Kern

Edgar Bolinth

Wolfgang Gröting

Karl-Heinz Pflaum

Hermann Rohling

Dirk Galda

Bernd Bienek

Kurt Aretz

Giancarlo Lombardi

Juergen Vollmer

Frank Burdack

The present invention seeks to improve data exchange in a communications system that is especially standardized according to IEEE 802.11a. For this purpose, when the transmission medium, preferably an IEEE 802.11 system with a distributed coordination function (DCF) is accessed in a decentralized manner, pilot signals are transmitted from the transmitter to the recipients using a number of transmission modes and then an allocation table regarding the transmission modes is calculated by the recipient on the basis of the pilot symbols received. The recipient transmits the allocation table to the transmitter so that the subsequent data exchange can proceed on the basis of the allocation table. In the case of centralized access, preferably an IEEE 802.11 system with a point coordination function (PCF), data exchange is improved in that the subsequent data are adaptively modulated already when the allocation table is transmitted.

Adaptive modulation and other extensions of the physical layer in multiple access systems

A method for reducing signaling overhead in a multicarrier system with dynamic bit allocation per subcarrier and a corresponding transmitter/receiver device, are provided wherein an established bit allocation table (BAT) that is provided with an index (I) is stored in a BAT storage device (LUT). In order to reduce signaling overhead, only the corresponding index (I) of an existing bit allocation table is transmitted (S).

Method for reducing signaling overhead in a multicarrier system with dynamic bit allocation and corresponding transmitter/receiver device

A method and OFDM receiver are provided for reducing the influence of harmonic interference on OFDM transmission systems, wherein high interference unity is achieved by the simultaneous use of a window function and a determined item of reliability information, the window function being a Nyquist-shaped window function which generates low side lobes in the subcarrier and interference spectra while simultaneously leaving the orthogonality of the subcarriers unchanged, the determined item of reliability information being derived from a measurement when transmitting a so-called zero symbol, in order to detect the instantaneously active interference signals, with the high interference immunity being achieved when the subcarrier-specific information is taken into account in a so-called Viterbi decoder.

Method and orthogonal frequency division multiplexing (OFDM) receiver for reducing the influence of harmonic interference on OFDM transmission systems

For a voice recognition system in a voice-controlled communication appliance, command words from a vocabulary are entered in text form and are transmitted to a separate converter station via a communication link initiated by the communication appliance, wherein the converter station performs word/model conversion on the command words and sends the reference models created in this way via a communication link to the terminal, in which they are stored and are made available to the voice recognition system.

Generation of a reference-model directory for a voice-controlled communications device

A method and apparatus are provided for operating a transmission amplifier, particularly a mobile communications terminal, with the transmission amplifier being fed with a supply voltage and with any nonlinearity of the transmission amplifier being substantially compensated for via a predistortion unit for data values in an input data stream, wherein, at least at the start of transmission operation or after a considerable change in the operating parameters, the transmission amplifier is operated with a supply voltage which is of such a magnitude that the transmission amplifier operates in the linear region, and the supply voltage for the transmission amplifier is reduced to the extent to which a quality factor for the compensation for the nonlinearity of the transmission amplifier is increased by the predistortion unit.

Method and apparatus for operating a transmission amplifier

An apparatus and a method for speech recognition are provided, by which, whereby the speech is optionally input via a microphone () close to the speaker or a microphone () remote from the speaker. A correction unit () is connected into the transmission channel () with microphone () close to the speaker, the correction unit modifying the electrical speech signal in such a way that it contains room transmission characteristics.

Apparatus and method for speech recognition

A communication system and associated method are provided, wherein a quality of service is detected in the communication system, coordination reorganization is performed in order to reorganize coordination functionalities for available stations in the communication system, the previous two steps are repeated for various coordination organizations in the communication system, the various qualities of service detected in the various coordination organizations are analyzed, and a coordination organization is selected on the basis of this analysis, whereupon communication is affected with an external communication system which uses the same transmission medium as the communication system.

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Bocholt, Germany

Ralf Kern