Siemens Aktiengesellschaft

U.S. Philips Corporation

Telefonaktiebolaget Lm Ericsson (publ)

Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V.

Alcatel

Deutschetelekom Ag

Ke Kommunikations-elektronic Gmbh & Co.

Broadband United Gmbh

Robert Fischer

Johannes B Huber

Wolfgang Gerstacker

Peter Schramm

Raimund Meyer

Ernst Eberlein

Heinz Gerhaeuser

Albert Heuberger

Axel Busboom

Johannes Ilg

Stefan Lipp

Christian Schneider

Stephan Buchholz

Sabah Badri

Stefan Muller

Thomas Reisinger

Ulrich Schrey

Claus Peter

Robert Bauml

Christoph Windpassinger

Georg Herrmann

Werner Henkel

Johannes Huber

Axel Broll

Several subscriber signals are transmitted simultaneously and at the same frequency by a central transmitter to several decentralized receivers which do not cooperate with each other, by digital message transmission in a broadcast channel. A common transmission signal, which enables an error-free individual reception, should be generated with knowledge of all subscriber signals and of the current transmission conditions, by signal preprocessing methods on the transmission side. Known nonlinear precoding methods totally suppress the interference signals, so that the channel diversity cannot be used. In the claimed precoding method, the occurring interference signals are, on the contrary, taken into account. On the basis of a modulo arithmetic calculation, the transmission channel is not totally equalized, but virtually divided, so that the transmission of the subscriber signals is continued periodically; the signals are selected according to the minimal transmission power and pre-equalized, in a linear manner, and the residual interferences, still remaining between the subscriber signals, may assume special values from a preset set of values. The set of values is selected, so that the interference signals of the other subscribers are also merely reflected in the otherwise already existing periodic continuation and can be suppressed or used as required by a modulo decision, on the reception side.

Nonlinear precoding method for a digital broadcast channel

A method for receiving first signals and further signals using a receiver, the first and further signals differing in at least one of the transmission parameters data rate, modulation type, wake-up criterion, synchronization and threshold value, comprises the steps of: in a first step, in a quiescent mode of the receiver, receiving and searching for a wake-up criterion (A) is performed intermittently using a first preset adjustable configuration of transmission parameters, and when no signal is received and no wake-up criterion (A) is found, the system switches to at least one further configuration and a search is made for a wake-up criterion (B).

Receiver and method for scanning and receiving wake-up signals with multiple configurations

An antitheft device for a motor vehicle has a first receiver () in the motor vehicle, which is designed to receive signals in narrowband. The signals received by this receiver are evaluated in accordance with the code information contained in them. Furthermore, the antitheft device has a second broadband receiver () which receives signals outside the useful frequency band (). If signals are received whose signal strength is above a threshold value (S), whose signal duration is shorter than a predefined time period (t&#x2013;t) or whose code information corresponds largely to anticipated code information, the access to the motor vehicle, and its use, are not enabled.

Antitheft device for a motor vehicle and a method for operating an antitheft device

A method of performing an echo phase offset correction in a multi-carrier demodulation system involves the step of differential phase decoding phase shifts based on a phase difference between simultaneous carriers having different frequencies. An echo phase offset is determined for each decoded phase shift by eliminating phase shift uncertainties related to the transmitted information from the decoded phase shift. The echo phase offsets are averaged in order to generate an averaged offset. Finally, each decoded phase shift is corrected based on the averaged offset.

Differential coding and carrier recovery for multicarrier systems

A method is described for digital transmission of information over copper lines wherein digital signals are precoded by a fixed precoder on a transmitter side and are recovered by blind equalization on a receiver side. The blind equalization is subdivided into an equalization of the magnitude and a subsequent equalization of the phase.

Method for digital transmission of information

The major problem in multicarrier transmission procedures consists in the very high crest factor of the transmit signal. This means, that very high signal peak values occur even with a moderate transmission power. It is the object of the invention to provide a method and device, whereby a definite reduction of signal peaks is achieved with moderate expenditure. This is obtained by generating, in addition to the information to be transmitted, several alternative, information-equivalent information sequences by means of determined reversible unambiguous representations. From these alternatives a sequence being favorable in view of the peak value of the pertinent transmit signal is selected and transmitted. The receiver is in a position to regenerate the original information from said receiving signal through the inversion of the performed representation.

Method and device for reducing the crest factor in digital transmission

Equalizer with a sequence estimation method with state reduction for a

Equalizer with extended channel estimation for a receiver in a digital

A process for distributing an aggregate rate and total transmitting power of a data stream over a plurality of channels in which the sub-rate (R.sub.i), capable of being transmitted over one channel, is calculated for each selected channel in accordance with the equation ##EQU1## R.sub.i being the sub-rate in the i-th channel, N.sub.i the average noise power first determined in the i-th channel, and D' being the number of actually used channels out of the channel group.

Process for distributing rate and power in a multicarrier transmission

A method for digital transmission of messages is indicated, in which each digital transmission symbol in a data stream to be transmitted is represented by one of several different possible signal values. The signal values of the transmission symbols are routed to a predistortion system, which counteracts their distortion in the transmission path, and whose output signal is transmitted through a linked transmission path. The transmitted signal is scanned at the end of the transmission path, it is then processed further and routed to a decoder. The maximum amplitude of the signal in the receiving-end decoder is limited by limiting the number of different possible signal values corresponding to each transmission symbol.

Method of digital transmission of messages using dynamic-range-limited

A remote-control access control device, particularly for motor vehicles, includes a stationary transmitter and receiver unit responding to actuation of tripping means for transmitting a question code signal, receiving an answer code signal, and furnishing an unlocking signal to an unlocking unit if the answer code signal matches a command code signal. A portable transponder has a receiver receiving the question code signal and a transmitter transmitting the answer code signal. The question code signal is repeatedly transmitted if no answer code signal has been received in response to an initial transmission, and a signal parameter is modified upon transmission of the answer code signal as a function of a field intensity of the question code signal or of a battery voltage of the transponder. Alternatively, a signal parameter is modified when the answer code signal is transmitted if an information content of the question code signal indicates an emergency operation state. As another alternative, the transmitter and receiver unit has both a transmission channel for receiving signals of low field intensity and a transmission channel for receiving signals of high field intensity. A method is also provided for operating the access control device.

Remote-control access control device and method for operating the same

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Erlangen, Germany

Robert Fischer