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).

  • Publication number: 20090207853
    Abstract: 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: Application
    Filed: February 11, 2009
    Publication date: August 20, 2009
    Inventors: Stefan Mueller-Weinfurtner, Karsten Brueninghaus, Udo Wachsmann
  • Publication number: 20090052598
    Abstract: 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: Application
    Filed: December 12, 2007
    Publication date: February 26, 2009
    Applicant: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Fabian WENGER, Uwe Dettmar, Udo Wachsmann, Peter Schramm
  • Publication number: 20090034667
    Abstract: 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: Application
    Filed: December 12, 2007
    Publication date: February 5, 2009
    Applicant: Telefonaktiebolaget LM Ericsson (publ),
    Inventors: Fabian WENGER, Uwe Dettmar, Udo Wachsmann, Peter Schramm
  • Patent number: 7477697
    Abstract: 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: Grant
    Filed: March 1, 2002
    Date of Patent: January 13, 2009
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Mathias Pauli, Eric Sachse, Udo Wachsmann
  • Patent number: 7366517
    Abstract: 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: Grant
    Filed: July 26, 2006
    Date of Patent: April 29, 2008
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Ralf Keller, Ralf Tonjes, Wolfgang Stahl, Jörn Thielecke, Jörg Huschke, Udo Wachsmann
  • Patent number: 7327817
    Abstract: 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: Grant
    Filed: January 5, 2004
    Date of Patent: February 5, 2008
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Fabian Wenger, Uwe Dettmar, Udo Wachsmann, Peter Schramm
  • Patent number: 7324599
    Abstract: 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: Grant
    Filed: January 5, 2004
    Date of Patent: January 29, 2008
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Georg Frank, Mathias Pauli, Udo Wachsmann, Peter Schramm
  • Patent number: 7324600
    Abstract: 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: Grant
    Filed: February 10, 2004
    Date of Patent: January 29, 2008
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Mathias Pauli, Udo Wachsmann
  • Publication number: 20070225002
    Abstract: 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: Application
    Filed: May 15, 2007
    Publication date: September 27, 2007
    Applicant: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Ralf Keller, Ralf Tonjes, Wolfgang Stahl, Jorn Thielecke, Jorg Huschke, Udo Wachsmann
  • Patent number: 7231183
    Abstract: 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: Grant
    Filed: October 9, 2003
    Date of Patent: June 12, 2007
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Mathias Pauli, Udo Wachsmann, Shiau-He (Shawn) Tsai
  • Publication number: 20070042778
    Abstract: 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: Application
    Filed: July 26, 2006
    Publication date: February 22, 2007
    Applicant: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Ralf Keller, Ralf Tonjes, Wolfgang Stahl, Jorn Thielecke, Jorg Huschke, Udo Wachsmann
  • Patent number: 7146132
    Abstract: 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: Grant
    Filed: June 26, 2001
    Date of Patent: December 5, 2006
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Ralf Keller, Ralf Tonjes, Wolfgang Stahl, Jörn Thielecke, Jörg Huschke, Udo Wachsmann
  • Publication number: 20060227904
    Abstract: 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: Application
    Filed: January 15, 2003
    Publication date: October 12, 2006
    Applicant: Telefonaktiebolaget LM Ericsson
    Inventors: Stefan Mueller-Weinfurtner, Peter Schramm, Udo Wachsmann
  • Patent number: 7120199
    Abstract: 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: Grant
    Filed: May 3, 2002
    Date of Patent: October 10, 2006
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Jörn Thielecke, Udo Wachsmann
  • Patent number: 7106709
    Abstract: 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: Grant
    Filed: November 28, 2001
    Date of Patent: September 12, 2006
    Assignee: Telefonaktiebologet LM Ericsson (publ)
    Inventors: Stefan Davidsson, Mathias Pauli, Peter Schramm, Fabian Wenger, Udo Wachsmann, Roger Walther
  • Patent number: 7009932
    Abstract: 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: Grant
    Filed: May 31, 2001
    Date of Patent: March 7, 2006
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Kirsten Matheus, Udo Wachsmann, Uwe Dettmar
  • Publication number: 20040219883
    Abstract: 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: Application
    Filed: October 9, 2003
    Publication date: November 4, 2004
    Inventors: Mathias Pauli, Udo Wachsmann, Shiau-He (Shawn) Tsai
  • Patent number: 6807154
    Abstract: 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: Grant
    Filed: October 11, 1999
    Date of Patent: October 19, 2004
    Assignee: Telefonaktiebolaget LM Ericsson
    Inventors: Göran Malmgren, Jamshid Khun-Jush, Hui Li, Uwe Dettmar, Peter Schramm, Jörn Thielecke, Udo Wachsmann
  • Publication number: 20040190639
    Abstract: 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: Application
    Filed: February 10, 2004
    Publication date: September 30, 2004
    Inventors: Mathias Pauli, Udo Wachsmann
  • Publication number: 20040180666
    Abstract: 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: Application
    Filed: January 5, 2004
    Publication date: September 16, 2004
    Applicant: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Fabian Wenger, Uwe Dettmar, Udo Wachsmann, Peter Schramm