Patents by Inventor Robert B. MacLeod

Robert B. MacLeod 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: 7817754
    Abstract: Performing approximate diagonalization of a correlation metric by user permutation to improve Multiuser Detector (MUD) processing. The system reorders the entries in the S-Matrix in order to move the bit decisions closer together in the decision tree. In one embodiment the reordering is a sequential pairwise correlation.
    Type: Grant
    Filed: December 1, 2005
    Date of Patent: October 19, 2010
    Assignee: BAE Systems Information and Electronic Systems Integration Inc.
    Inventor: Robert B. MacLeod
  • Patent number: 7783110
    Abstract: One embodiment is a system for processing a complex ambiguity function (CAF) comprising creating a CAF surface from incoming data and a model vector, wherein the CAF surface has at least one feature, processing for a peak value, establishing a sub-window about the peak, wherein the peak is within the sub-window, and flattening the peak.
    Type: Grant
    Filed: April 10, 2006
    Date of Patent: August 24, 2010
    Assignee: BAE Systems Information and Electronic Systems Integration Inc.
    Inventor: Robert B MacLeod
  • Patent number: 7269223
    Abstract: The present invention is a digital communication method that increases the overall throughput of a Multiuser Detection (MUD)-based co-channel multiple access (MA) system in terms of the total number of bits transmitted through the shared medium by all the users of the MA system if signals are allowed to interfere. The total number of users can be increased if more dimensions are used for assigning the transmitted signals and the same dimensions are measured at the receiver. Specifically, the present invention does not require any coordination among transmitters but simply requires a transmitter to send its signal with either a randomly chosen polarization ellipse, or an assigned or randomly chosen amplitude level.
    Type: Grant
    Filed: April 16, 2003
    Date of Patent: September 11, 2007
    Assignee: BAE Systems Information and Electronic Systems Integration Inc.
    Inventors: Rachel E. Learned, Matthew A. Taylor, Robert B. MacLeod
  • Patent number: 7245673
    Abstract: Windowed multiuser detection techniques are disclosed. A window of data is established, and certain central bits within the window are selected as reliable, while other side bits are ignored. The selected bits are demodulated. The windowed multiuser detector moves along to the next window in such a manner that the next group of central bit decisions lay contiguous with the previous set, and eventually every bit to be demodulated has at some point been a central bit decision. Most any type of MUD algorithm (e.g., MMSE algorithm MUD or M-algorithm MUD) can be used to compute estimates in the windowed data. Unreliable windowed data are distinguished from reliable data (e.g., weighting or other de-emphasis scheme).
    Type: Grant
    Filed: June 25, 2003
    Date of Patent: July 17, 2007
    Assignee: Bae Systems Information and Electronic Systems Integration Inc.
    Inventor: Robert B. MacLeod
  • Patent number: 7236546
    Abstract: A multiple access processing system for a plurality of users employing a multiuser detector processing partial blocks of data within a window. The multiuser detector processes the data for all users within a processing window and is interrupted at successive frame boundaries. Once an entire block is processed by the MUD, the blocks for that user are decoded and the processing continues.
    Type: Grant
    Filed: September 10, 2003
    Date of Patent: June 26, 2007
    Assignee: Bae Systems Information and Electronic Systems Integration Inc.
    Inventors: Dianne E Egnor, Robert B MacLeod
  • Patent number: 7190747
    Abstract: Techniques for compensating for frequency mismatch between transmitters and receivers of a multiuser communication system having a plurality of users are disclosed. In particular, the mismatch of carrier frequency estimates are estimated and compensated for each user of the system. This is accomplished without increasing the training overhead of the system. Symbol phase drift and offset is computed by estimating phase error profile parameters (e.g., slope and offset). The disclosed techniques may be used to correct for symbol rotation in any one decision region, or in neighboring decision regions.
    Type: Grant
    Filed: April 25, 2003
    Date of Patent: March 13, 2007
    Assignee: BAE Systems Information and Electronic Systems Integration Inc.
    Inventors: Robert B MacLeod, Joshua D Niedzwiecki, Kari M Karwedsky
  • Patent number: 7126890
    Abstract: Techniques for reading data from a storage medium (150) having a high track density prone to adjacent track interference are disclosed. One or more sensing elements (120) are used to extract data stored on adjacent tracks. Multiuser detection (130) is then used to detect/decode a single track that is closely spaced to its neighboring tracks, resolve interference from adjacent tracks, or to simultaneously detect/decode multiple adjacent closely packed tracks.
    Type: Grant
    Filed: September 19, 2003
    Date of Patent: October 24, 2006
    Assignee: Bae Systems Information and Electronic Systems Integration INC
    Inventors: Rachel E. Learned, Robert B. MacLeod
  • Patent number: 7110439
    Abstract: A system is provided for use with a multi-user detector MUD, which dramatically decreases the processing time for separating out interfering transmissions from a number of users by eliminating from each processing iteration consideration of those bit estimates for which the probability or estimate of their value exceeds a predetermined threshold and can therefore be declared “certain”. In a Turbo MUD environment in which the output of the MUD is coupled back to the MUD through an error correction system, the output of the error correction is thresholded such that those bit estimates having probabilities or estimates greater than a predetermined threshold are assigned a quantized value and are eliminated from further processing by the MUD. For certain low-complexity processing Turbo MUDs there can be as much of a reduction as one-third in processing time, whereas for full MUD processing, the reduction in processing time can be as much as 1/30th.
    Type: Grant
    Filed: March 25, 2002
    Date of Patent: September 19, 2006
    Assignee: BAE Systems Information and Electronic Systems Integration Inc.
    Inventor: Robert B. MacLeod
  • Patent number: 7092452
    Abstract: A digital receiver automatically detects and non-coherently demodulates a multiplicity of interfering digitally modulated signals transmitted simultaneously at approximately the same carrier frequency. The receiver includes one or more antenna inputs (e.g., polarization and/or space diverse), a parameter estimator module, and a multiuser detector for estimating the data transmitted by each interfering signals and adapted to operate with at least one of a MUD algorithm with partially quantized prior information and a MUD algorithm based on prewhitened data.
    Type: Grant
    Filed: April 25, 2003
    Date of Patent: August 15, 2006
    Assignee: Bae Systems Information and Electronic Systems Integration INC
    Inventors: Matthew A Taylor, Robert B MacLeod, Rachel E Learned, Joshua D Niedzwiecki, Karl D Brommer, Thomas P McElwain
  • Patent number: 6947502
    Abstract: A Parameter Estimator for accurately estimating signature responses of multiple co-channel interfering digital transmission signals. The Parameter Estimator is used in a Multiuser Detection (MUD) Receiver to significantly reduce the error rate. The Parameter Estimator comprises a plurality of software components, including a Signature Waveform Estimator, Training Sequence Locator, Noise Estimator, Active Users Tester, Initial Transformation Matrix Builder, a Transformation Matrix Rebuilder, and a Transformation Matrix Selector, and generates an estimated noise power, a training sequence index and estimated signature waveforms.
    Type: Grant
    Filed: August 26, 2002
    Date of Patent: September 20, 2005
    Inventors: Matthew A. Taylor, Joshua D. Niedzwiecki, Robert B. MacLeod
  • Publication number: 20040267957
    Abstract: Windowed multiuser detection techniques are disclosed. A window of data is established, and certain central bits within the window are selected as reliable, while other side bits are ignored. The selected bits are demodulated. The windowed multiuser detector moves along to the next window in such a manner that the next group of central bit decisions lay contiguous with the previous set, and eventually every bit to be demodulated has at some point been a central bit decision. Most any type of MUD algorithm (e.g., MMSE algorithm MUD or M-algorithm MUD) can be used to compute estimates in the windowed data. Unreliable windowed data are distinguished from reliable data (e.g., weighting or other de-emphasis scheme).
    Type: Application
    Filed: February 11, 2004
    Publication date: December 30, 2004
    Inventor: Robert B MacLeod
  • Patent number: 6831574
    Abstract: A Turbo multi-user detector (MUD) processing system in multiple access communications channels that decreases the likelihood of improper decoding of the final values of interest, thereby allowing for a reduction in the number of iterations performed and lowers complexity without negatively impacting performance. The present invention comprises a multi-user detector serially concatenated to two decoder sections in such a manner that data flows iteratively from the MUD and to each detector stage and back to the MUD to correct for errors.
    Type: Grant
    Filed: October 3, 2003
    Date of Patent: December 14, 2004
    Assignee: BAE Systems Information and Electronic Systems Integration INC
    Inventors: Diane G. Mills, Robert B. MacLeod, Thomas P. McElwain, Dianne E. Egnor
  • Patent number: 6826140
    Abstract: A processing scheme for digital storage media using multi-user detection to separate tracks of data or remove interference from neighboring tracks. In one embodiment, data is written on a plurality of tracks positioned sufficiently close together so that multiple tracks are detected simultaneously by the read access sensor. Upon scanning the surface for data, the read element simultaneously receives the data signals from a plurality of tracks. Joint detection signal processing resolves the interference and data bits from the multiple sensed tracks, enabling closer packing of data with minimal guard space.
    Type: Grant
    Filed: September 20, 2002
    Date of Patent: November 30, 2004
    Assignee: BAE Systems Information and Electronic Systems Integration INC
    Inventors: Karl D. Brommer, Robert B. MacLeod, Michael P. Schmidt
  • Publication number: 20040208251
    Abstract: The present invention is a digital communication method that increases the overall throughput of a MUD-based co-channel multiple access (MA) system in terms of the total number of bits transmitted through the shared medium by all the users of the MA system if signals are allowed to interfere. The total number of users can be increased if more dimensions are used for assigning the transmitted signals and the same dimensions are measured at the receiver. Specifically, the present invention does not require any coordination among transmitters but simply requires a transmitter to send its signal with either a randomly chosen polarization ellipse, or an assigned or randomly chosen amplitude level.
    Type: Application
    Filed: April 16, 2003
    Publication date: October 21, 2004
    Inventors: Rachel E. Learned, Matthew A. Taylor, Robert B. MacLeod
  • Publication number: 20040037202
    Abstract: A processing scheme for digital storage media using multi-user detection to separate tracks of data or remove interference from neighboring tracks. In one embodiment, data is written on a plurality of tracks positioned sufficiently close together so that multiple tracks are detected simultaneously by the read access sensor. Upon scanning the surface for data, the read element simultaneously receives the data signals from a plurality of tracks. Joint detection signal processing resolves the interference and data bits from the multiple sensed tracks, enabling closer packing of data with minimal guard space.
    Type: Application
    Filed: September 20, 2002
    Publication date: February 26, 2004
    Inventors: Karl D. Brommer, Robert B. MacLeod, Michael P. Schmidt
  • Publication number: 20030198305
    Abstract: A digital receiver automatically detects and non-coherently demodulates a multiplicity of interfering digitally modulated signals transmitted simultaneously at approximately the same carrier frequency. The receiver includes one or more antenna inputs (e.g., polarization and/or space diverse), a parameter estimator module, and a multiuser detector for estimating the data transmitted by each interfering signals and adapted to operate with at least one of a MUD algorithm with partially quantized prior information and a MUD algorithm based on prewhitened data.
    Type: Application
    Filed: April 25, 2003
    Publication date: October 23, 2003
    Inventors: Matthew A. Taylor, Robert B. MacLeod, Rachel E. Learned, Joshua D. Niedzwiecki, Karl D. Brommer, Thomas P. McElwain
  • Publication number: 20030198303
    Abstract: A Parameter Estimator for accurately estimating signature responses of multiple co-channel interfering digital transmission signals. The Parameter Estimator is used in a Multiuser Detection (MUD) Receiver to significantly reduce the error rate. The Parameter Estimator comprises a plurality of software components, including a Signature Waveform Estimator, Training Sequence Locator, Noise Estimator, Active Users Tester, Initial Transformation Matrix Builder, a Transformation Matrix Rebuilder, and a Transformation Matrix Selector, and generates an estimated noise power, a training sequence index and estimated signature waveforms.
    Type: Application
    Filed: August 26, 2002
    Publication date: October 23, 2003
    Inventors: Matthew A. Taylor, Joshua D. Niedzwiecki, Robert B. MacLeod
  • Publication number: 20030187928
    Abstract: Techniques for compensating for frequency mismatch between transmitters and receivers of a multiuser communication system having a plurality of users are disclosed. In particular, the mismatch of carrier frequency estimates are estimated and compensated for each user of the system. This is accomplished without increasing the training overhead of the system. Symbol phase drift and offset is computed by estimating phase error profile parameters (e.g., slope and offset). The disclosed techniques may be used to correct for symbol rotation in any one decision region, or in neighboring decision regions.
    Type: Application
    Filed: April 25, 2003
    Publication date: October 2, 2003
    Inventors: Robert B. MacLeod, Joshua D. Niedzwiecki, Kari M. Karwedsky
  • Publication number: 20030182369
    Abstract: A system is provided for use with a multi-user detector MUD, which dramatically decreases the processing time for separating out interfering transmissions from a number of users by eliminating from each processing iteration consideration of those bit estimates for which the probability or estimate of their value exceeds a predetermined threshold and can therefore be declared “certain”. In a Turbo MUD environment in which the output of the MUD is coupled back to the MUD through an error correction system, the output of the error correction is thresholded such that those bit estimates having probabilities or estimates greater than a predetermined threshold are assigned a quantized value and are eliminated from further processing by the MUD. For certain low-complexity processing Turbo MUDs there can be as much of a reduction as one-third in processing time, whereas for full MUD processing, the reduction in processing time can be as much as {fraction (1/30)}th.
    Type: Application
    Filed: March 25, 2002
    Publication date: September 25, 2003
    Applicant: BAE SYSTEMS Information Electronic Systems Integration, Inc.
    Inventor: Robert B. MacLeod
  • Patent number: 5777949
    Abstract: A passive target detection system for use with a moving platform which indes a module for postulating modeled target signals based upon a number of factors including at least one factor selected from the group consisting of signal beam pattern, frequency, non-linear signal progression and carrier movement; a receiver for receiving signals from a target; and a comparison unit for comparing the signals with the modeled target signals, for determining location of the target.
    Type: Grant
    Filed: January 23, 1997
    Date of Patent: July 7, 1998
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Robert B. MacLeod, Walter T. Schneider