Patents by Inventor Nikolaos D. Sidiropoulos

Nikolaos D. Sidiropoulos 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).

  • Patent number: 10374676
    Abstract: In general, this disclosure describes techniques for beamforming using limited feedback that exploit the spatio-temporal channel correlation and avoid the limitations of codebook-based feedback and Markov chain modeling. In one example, a receiving device includes a plurality of receive antennas for receiving communication information, a memory for storing the communication information, and one or more processors for processing the communication information. The one or more processors are configured to receive, through a wireless communication channel, a pilot signal transmitted by a transmitting device, determine, based on the received pilot signal, channel state feedback comprising a quantized representation of the pilot signal as received at the receiving device, and send, through the wireless communication.
    Type: Grant
    Filed: April 20, 2017
    Date of Patent: August 6, 2019
    Assignee: Regents of the University of Minnesota
    Inventors: Nikolaos D. Sidiropoulos, Omar A. Mehanna
  • Publication number: 20170289835
    Abstract: In general, this disclosure describes techniques for beamforming using limited feedback that exploit the spatio-temporal channel correlation and avoid the limitations of codebook-based feedback and Markov chain modeling. In one example, a receiving device includes a plurality of receive antennas for receiving communication information, a memory for storing the communication information, and one or more processors for processing the communication information.
    Type: Application
    Filed: April 20, 2017
    Publication date: October 5, 2017
    Applicant: Regents of the University of Minnesota
    Inventors: Nikolaos D. Sidiropoulos, Omar A. Mehanna
  • Patent number: 9647745
    Abstract: In general, this disclosure describes techniques for beamforming using limited feedback that exploit the spatio-temporal channel correlation and avoid the limitations of codebook-based feedback and Markov chain modeling. In one example, a receiving device includes a plurality of receive antennas for receiving communication information, a memory for storing the communication information, and one or more processors for processing the communication information. The one or more processors are configured to receive, through a wireless communication channel, a pilot signal transmitted by a transmitting device, determine, based on the received pilot signal, channel state feedback comprising a quantized representation of the pilot signal as received at the receiving device, and send, through the wireless communication.
    Type: Grant
    Filed: October 14, 2015
    Date of Patent: May 9, 2017
    Assignee: Regents of the University of Minnesota
    Inventors: Nikolaos D. Sidiropoulos, Omar A. Mehanna
  • Publication number: 20160105230
    Abstract: In general, this disclosure describes techniques for beamforming using limited feedback that exploit the spatio-temporal channel correlation and avoid the limitations of codebook-based feedback and Markov chain modeling. In one example, a receiving device includes a plurality of receive antennas for receiving communication information, a memory for storing the communication information, and one or more processors for processing the communication information.
    Type: Application
    Filed: October 14, 2015
    Publication date: April 14, 2016
    Inventors: Nikolaos D. Sidiropoulos, Omar A. Mehanna
  • Patent number: 8599901
    Abstract: A frequency hopping signal receiving system comprising: a receiver for extracting discrete-time samples from the signal; a memory connected to the receiver for storing the extracted discrete-time samples from the signal; at least one processor operatively connected to the memory for: determining a state-space vector that captures relevant information to describe the dynamics of the signal; selecting a parameter to represent the probability of hopping associated with the signal; generating particle filters to estimate unknown parameters in the state-space vector based upon the extracted discrete-time samples by generating random particles that approximate the filtering distribution having importance weights; specifying the importance function in closed-form in a convenient mixture representation, which enables drawing particles and updating the importance weights; constructing an estimator to generate hop particles based upon observing at least one sample hop and then evaluating the estimator using a condition
    Type: Grant
    Filed: April 5, 2010
    Date of Patent: December 3, 2013
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Efthimios E. Tsakonas, Nikolaos D. Sidiropoulos, Ananthram Swami
  • Publication number: 20110243192
    Abstract: A frequency hopping signal receiving system comprising: a receiver for extracting discrete-time samples from the signal; a memory connected to the receiver for storing the extracted discrete-time samples from the signal; at least one processor operatively connected to the memory for: determining a state-space vector that captures relevant information to describe the dynamics of the signal; selecting a parameter to represent the probability of hopping associated with the signal; generating particle filters to estimate unknown parameters in the state-space vector based upon the extracted discrete-time samples by generating random particles that approximate the filtering distribution having importance weights; specifying the importance function in closed-form in a convenient mixture representation, which enables drawing particles and updating the importance weights; constructing an estimator to generate hop particles based upon observing at least one sample hop and then evaluating the estimator using a condition
    Type: Application
    Filed: April 5, 2010
    Publication date: October 6, 2011
    Applicant: U.S. Government as represented by the Secretary of the Army
    Inventors: EFTHIMIOS E. TSAKONAS, NIKOLAOS D. SIDIROPOULOS
  • Patent number: 6127669
    Abstract: A window and level control tool that operates in real time and can quickly determine initial values for window and level settings such that a displayed image is always presented in a readable format is disclosed. The invention transforms input image data into an image histogram. This histogram is then segmented into a small number of parts corresponding to structures of interest. Segmentation of the histogram is done by a novel Viterbi optimal runlength-constrained approximation nonlinear filter. Window and level settings are calculated to correspond to this optimal segmentation. A readable image of one of the structures of interest is then displayed. In another embodiment, the tool provides a menu of optimal window and level settings corresponding to the different types of information a radiologist may be interested in.
    Type: Grant
    Filed: January 29, 1998
    Date of Patent: October 3, 2000
    Assignee: University of Maryland
    Inventors: Nikolaos D. Sidiropoulos, John S. Baras