Patents by Inventor Udo Wachsmann
Udo Wachsmann has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20090207853Abstract: A technique is provided for determining the configuration of a sub-frame having data symbols including cyclic-prefixes. In some communication standards such as the Long Term Evolution (LTE) standard, a plurality of possible configurations exist for a sub-frame, with each configuration being identifiable by a certain cyclic-prefix length. In an exemplary method realization, the technique includes receiving a data signal comprising the sub-frame, evaluating one or more hypotheses of the cyclic prefix length to produce one or more corresponding evaluation results, and, based on the evaluation results, deciding on a most-likely cyclic prefix length, according to which the sub-frame configuration is determined. The hypothesis evaluation may involve autocorrelation and cyclic accumulation of samples of the received data signal.Type: ApplicationFiled: February 11, 2009Publication date: August 20, 2009Inventors: Stefan Mueller-Weinfurtner, Karsten Brueninghaus, Udo Wachsmann
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Publication number: 20090052598Abstract: A method and a device of providing timing information within a wireless communication system is described. The timing information is extracted from a received transmit signal. The inventive method comprises the steps of providing a training signal on the receiver side relating to a known signal portion of the transmit signal, scaling the training signal, quantizing the scaled training signal, correlating one or more parts of the received transmit signal with the scaled training signal to obtain one or more correlation results, and determining the timing information on the basis of the correlation results.Type: ApplicationFiled: December 12, 2007Publication date: February 26, 2009Applicant: Telefonaktiebolaget LM Ericsson (publ)Inventors: Fabian WENGER, Uwe Dettmar, Udo Wachsmann, Peter Schramm
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Publication number: 20090034667Abstract: A method and a device of providing timing information within a wireless communication system is described. The timing information is extracted from a received transmit signal. The inventive method comprises the steps of providing a training signal on the receiver side relating to a known signal portion of the transmit signal, scaling the training signal, quantizing the scaled training signal, correlating one or more parts of the received transmit signal with the scaled training signal to obtain one or more correlation results, and determining the timing information on the basis of the correlation results.Type: ApplicationFiled: December 12, 2007Publication date: February 5, 2009Applicant: Telefonaktiebolaget LM Ericsson (publ),Inventors: Fabian WENGER, Uwe Dettmar, Udo Wachsmann, Peter Schramm
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Patent number: 7477697Abstract: The invention relates to a method of multiplexing data words in a multicarrier transmit diversity system. The method comprises the step of generating a plurality of data blocks, each data block comprising data words and each data word containing data symbols derived from a data signal, the step of determining for one or more data blocks in dependence on at least one transmission constraint if the data words of said one or more data blocks are to be multiplexed in the time domain or in the frequency domain and the step of multiplexing the data words of the data blocks in accordance with the determination result.Type: GrantFiled: March 1, 2002Date of Patent: January 13, 2009Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventors: Mathias Pauli, Eric Sachse, Udo Wachsmann
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Patent number: 7366517Abstract: Method of arranging a cellular radio network in a geographical area which is already covered by an existing cellular radio network, wherein cell clusters of the cellular radio network to be introduced and using a specific transmission frequency are located in areas determined by connecting at least two cells of the existing cellular radio network using the specific transmission frequency, and wherein the cell clusters are arranged such that they do not overlap with the cells of the existing cellular radio network. The cell clusters of the introduced cellular radio network may be adjusted by reducing the cell size of cell clusters of the introduced cellular radio network, and by introducing new cells into cell clusters of the introduced cellular radio network. The invention allows to reuse frequencies of an existing cellular radio network by an introduced cellular radio network in the same geographical area.Type: GrantFiled: July 26, 2006Date of Patent: April 29, 2008Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventors: Ralf Keller, Ralf Tonjes, Wolfgang Stahl, Jörn Thielecke, Jörg Huschke, Udo Wachsmann
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Patent number: 7327817Abstract: A method and a device of providing timing information within a wireless communication system is described. The timing information is extracted from a received transmit signal. The inventive method comprises the steps of providing a training signal on the receiver side relating to a known signal portion of the transmit signal, scaling the training signal, quantizing the scaled training signal, correlating one or more parts of the received transmit signal with the scaled training signal to obtain one or more correlation results, and determining the timing information on the basis of the correlation results.Type: GrantFiled: January 5, 2004Date of Patent: February 5, 2008Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventors: Fabian Wenger, Uwe Dettmar, Udo Wachsmann, Peter Schramm
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Patent number: 7324599Abstract: In order to correct frequency deviations of signals in a multicarrier system, such as a OFDM-system, the present invention provides a frequency tracker and a method to operate the same. The frequency tracker is based on a decision directed digital phase locked loop exhibiting a predictive character. On the basis of an estimated phase offset for a received signal (signal component, signal symbol) a predicted phase offset is calculated and applied to the signal (signal component, signal symbol). Further, received signals (signal components, signal symbols) are sampled and for each sample a sample phase offset to be corrected is calculated in dependence to the related estimated phase offset to incorporate the predictive character.Type: GrantFiled: January 5, 2004Date of Patent: January 29, 2008Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventors: Georg Frank, Mathias Pauli, Udo Wachsmann, Peter Schramm
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Patent number: 7324600Abstract: A method and a stage for estimating channel coefficients in a multi carrier system operating in accordance with a block-code based transmit diversity scheme, in which a data content of a code matrix is multiplexed in a frequency domain are described. The method comprises determining a phase ramp in the frequency domain or an equivalent thereof in the time domain, the phase ramp or the equivalent thereof being comprised within a receive signal after timing synchronization, processing the receive signal to remove the phase ramp or the equivalent thereof and estimating the channel coefficients on the basis of the processed receive signal.Type: GrantFiled: February 10, 2004Date of Patent: January 29, 2008Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventors: Mathias Pauli, Udo Wachsmann
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Publication number: 20070225002Abstract: Method of arranging a cellular radio network in a geographical area which is already covered by an existing cellular radio network, wherein cell clusters of the cellular radio network to be introduced and using a specific transmission frequency are located in areas determined by connecting at least two cells of the existing cellular radio network using the specific transmission frequency, and wherein the cell clusters are arranged such that they do not overlap with the cells of the existing cellular radio network. The cell clusters of the introduced cellular radio network may be adjusted by reducing the cell size of cell clusters of the introduced cellular radio network, and by introducing new cells into cell clusters of the introduced cellular radio network. The invention allows to reuse frequencies of an existing cellular radio network by an introduced cellular radio network in the same geographical area.Type: ApplicationFiled: May 15, 2007Publication date: September 27, 2007Applicant: Telefonaktiebolaget LM Ericsson (publ)Inventors: Ralf Keller, Ralf Tonjes, Wolfgang Stahl, Jorn Thielecke, Jorg Huschke, Udo Wachsmann
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Patent number: 7231183Abstract: A method and a receiver for determining the quality of a wireless communications link are described. The link quality is determined on the basis of an encoded signal that is transmitted via the communications link and that includes at least two signal portions experiencing different states of one or more transmission channels. The method comprises the steps of providing individual channel quality values for the different channels and determining a quality measure indicative of the link quality by averaging the individual channel quality values in the exponential domain.Type: GrantFiled: October 9, 2003Date of Patent: June 12, 2007Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventors: Mathias Pauli, Udo Wachsmann, Shiau-He (Shawn) Tsai
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Publication number: 20070042778Abstract: Method of arranging a cellular radio network in a geographical area which is already covered by an existing cellular radio network, wherein cell clusters of the cellular radio network to be introduced and using a specific transmission frequency are located in areas determined by connecting at least two cells of the existing cellular radio network using the specific transmission frequency, and wherein the cell clusters are arranged such that they do not overlap with the cells of the existing cellular radio network. The cell clusters of the introduced cellular radio network may be adjusted by reducing the cell size of cell clusters of the introduced cellular radio network, and by introducing new cells into cell clusters of the introduced cellular radio network. The invention allows to reuse frequencies of an existing cellular radio network by an introduced cellular radio network in the same geographical area.Type: ApplicationFiled: July 26, 2006Publication date: February 22, 2007Applicant: Telefonaktiebolaget LM Ericsson (publ)Inventors: Ralf Keller, Ralf Tonjes, Wolfgang Stahl, Jorn Thielecke, Jorg Huschke, Udo Wachsmann
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Patent number: 7146132Abstract: Method of arranging a cellular radio network in a geographical area which is already covered by an existing cellular radio network, wherein cell clusters of the cellular radio network to be introduced and using a specific transmission frequency are located in areas determined by connecting at least two cells of the existing cellular radio network using the specific transmission frequency, and wherein the cell clusters are arranged such that they do not overlap with the cells of the existing cellular radio network. The cell clusters of the introduced cellular radio network may be adjusted by reducing the cell size of cell clusters of the introduced cellular radio network, and by introducing new cells into cell clusters of the introduced cellular radio network. The invention allows to reuse frequencies of an existing cellular radio network by an introduced cellular radio network in the same geographical area.Type: GrantFiled: June 26, 2001Date of Patent: December 5, 2006Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventors: Ralf Keller, Ralf Tonjes, Wolfgang Stahl, Jörn Thielecke, Jörg Huschke, Udo Wachsmann
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Publication number: 20060227904Abstract: The present invention concerns a method for estimating the time-dispersion of a channel comprising D subchannels, wherein one computes from a received signal a set of estimated Channel Transfer Factors (CTF's) ?[?], where ?(0???D) is the subchannel number, said method comprising a step of calculating, for a predetermined strictly positive integer d, a correlation factor Cd representing the correlations, both in amplitude and in phase, between pairs ?[?] and ?[?+d] of said computed CTF estimates. By an appropriate choice of d, the time-dispersion resolution can be adapted to most prevalent channels. The correlation is optionally corrected according to the mean channel estimation signal-to-noise ratio. This method can be used for many applications where knowing the time-dispersion characteristics of a channel is required, and is, for example, particularly suitable for designing a channel estimation filter, and for link adaptation. Application to devices and apparatus implementing these methods.Type: ApplicationFiled: January 15, 2003Publication date: October 12, 2006Applicant: Telefonaktiebolaget LM EricssonInventors: Stefan Mueller-Weinfurtner, Peter Schramm, Udo Wachsmann
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Patent number: 7120199Abstract: MIMO transmission methods are applied to communicaiton systems in which a transmitter has more than one transmit antenna and a receiver has more than one receive antenna. Information to be transmitted is divided into a plurality of subsignals according to the number of used transmit antennas and each subsignal is processed separately before it is emitted by the respective transmit antenna. In the receiver the different receive signals are processed thus that subsignals are detected and decoded and the contribution of each detected and decoded subsignal is subtracted from the receive signals and whereby a feedback channel from receiver to transmitter is used to send control information to the transmitter depending on the receive situation.Type: GrantFiled: May 3, 2002Date of Patent: October 10, 2006Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventors: Jörn Thielecke, Udo Wachsmann
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Patent number: 7106709Abstract: A radio receiver system (30) comprises a radio receiver (41), a receiver sample clock (60), which is used for sampling a modulated base-band signal; and a timing correction unit (100). The timing correction unit (100) performs, in the frequency domain, a timing drift compensation between a transmitter sample clock (66) and the receiver sample clock (60). In one example context of implementation, the plural modulated radio frequency carriers have been modulated using Orthogonal Frequency Division Multiplexing (OFDM).Type: GrantFiled: November 28, 2001Date of Patent: September 12, 2006Assignee: Telefonaktiebologet LM Ericsson (publ)Inventors: Stefan Davidsson, Mathias Pauli, Peter Schramm, Fabian Wenger, Udo Wachsmann, Roger Walther
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Patent number: 7009932Abstract: A frequency tracking device (FTD) in particular for use in a OFDM communication system comprises a selector (SEL) which selects on the basis of N channel coefficients (Cest) a number M of subcarriers corresponding to the M channel coefficients (Cest) having the largest absolute values. An evaluator (EVAL) of the frequency tracking device (FTD) determines a frequency deviation estimate (foff,est) on the basis of the selected M subcarriers and the selected M channel coefficients. In addition to or instead of a feedback correction unit (CORR1) provided upstream of a multi-carrier filter bank (8; FFT), the frequency tracking device (FTD) can also comprise a feed forward correction unit (CORR2) provided downstream of the receiver multi-carrier filter bank (8).Type: GrantFiled: May 31, 2001Date of Patent: March 7, 2006Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventors: Kirsten Matheus, Udo Wachsmann, Uwe Dettmar
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Publication number: 20040219883Abstract: A method and a receiver for determining the quality of a wireless communications link are described. The link quality is determined on the basis of an encoded signal that is transmitted via the communications link and that includes at least two signal portions experiencing different states of one or more transmission channels. The method comprises the steps of providing individual channel quality values for the different channels and determining a quality measure indicative of the link quality by averaging the individual channel quality values in the exponential domain.Type: ApplicationFiled: October 9, 2003Publication date: November 4, 2004Inventors: Mathias Pauli, Udo Wachsmann, Shiau-He (Shawn) Tsai
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Patent number: 6807154Abstract: A TDMA/TDD link adaptation method determines radio link quality at a base station. The radio link quality is used to update and broadcast a physical layer parameter indicator (10-16) from the base station on a broadcast control channel having a common physical layer parameter indicator for all uplink and downlink channels.Type: GrantFiled: October 11, 1999Date of Patent: October 19, 2004Assignee: Telefonaktiebolaget LM EricssonInventors: Göran Malmgren, Jamshid Khun-Jush, Hui Li, Uwe Dettmar, Peter Schramm, Jörn Thielecke, Udo Wachsmann
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Publication number: 20040190639Abstract: A method and a stage (60) for estimating channel coefficients in a multi carrier system operating in accordance with a block-code based transmit diversity scheme, in which a data content of a code matrix is multiplexed in a frequency domain are described. The method comprises determining a phase ramp (&phgr;est) in the frequency domain or an equivalent (&Dgr;t) thereof in the time domain, the phase ramp (&phgr;est) or the equivalent (&Dgr;t) thereof being comprised within a receive signal (Y) after timing synchronization, processing the receive signal (Y&Dgr;t) to remove the phase ramp (&phgr;est) or the equivalent (&Dgr;t) thereof and estimating the channel coefficients on the basis of the processed receive signal.Type: ApplicationFiled: February 10, 2004Publication date: September 30, 2004Inventors: Mathias Pauli, Udo Wachsmann
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Publication number: 20040180666Abstract: A method and a device of providing timing information within a wireless communication system is described. The timing information is extracted from a received transmit signal. The inventive method comprises the steps of providing a training signal on the receiver side relating to a known signal portion of the transmit signal, scaling the training signal, quantizing the scaled training signal, correlating one or more parts of the received transmit signal with the scaled training signal to obtain one or more correlation results, and determining the timing information on the basis of the correlation results.Type: ApplicationFiled: January 5, 2004Publication date: September 16, 2004Applicant: Telefonaktiebolaget LM Ericsson (publ)Inventors: Fabian Wenger, Uwe Dettmar, Udo Wachsmann, Peter Schramm