Patents by Inventor Suhas N. Diggavi

Suhas N. Diggavi 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: 7450656
    Abstract: In an environment where a block transmission takes place via a frequency selective channel that is characterized by channel parameters that change with time in the course of the transmission of a block, an arrangement employs pilot signals to ascertain some of the parameters, and estimates the remaining parameters through an interpolation process. In some embodiments, channel coefficients estimates are improved by employing estimates from previous blocks. In an OFDM system, the pilot signals are advantageously selected to be in clusters that are equally spaced from each other in the time or the frequency domains. This approach applies to multiple antennae arrangements, as well as to single antenna arrangements, and to arrangements that do, or do not, use space-time coding.
    Type: Grant
    Filed: July 21, 2006
    Date of Patent: November 11, 2008
    Assignee: AT&T Corp.
    Inventors: Naofal Al-Dhahir, Suhas N. Diggavi, Anastasios Stamoulis
  • Patent number: 7173975
    Abstract: In an environment where a block transmission takes place via a frequency selective channel that is characterized by channel parameters that change with time in the course of the transmission of a block, an arrangement employs pilot signals to ascertain some of the parameters, and estimates the remaining parameters through an interpolation process. In some embodiments, channel coefficients estimates are improved by employing estimates from previous blocks. In an OFDM system, the pilot signals are advantageously selected to be in clusters that are equally spaced from each other in the time or the frequency domains. This approach applies to multiple antennae arrangements, as well as to single antenna arrangements, and to arrangements that do, or do not, use space-time coding.
    Type: Grant
    Filed: May 21, 2002
    Date of Patent: February 6, 2007
    Inventors: Naofal Al-Dhahir, Suhas N. Diggavi, Anastasios Stamoulis
  • Patent number: 7130355
    Abstract: In an environment where the transmission medium leading to the receiver is time-variant within a block of received signals, and where transmission medium has an finite impulse response extending over a number of symbols intervals, a receiver that includes a filter that, based on an estimate of the transmission channel, is controlled to have filter coefficients that minimize inter-carrier interference due to the intra-block time variations in the transmission medium. The estimate channel coefficients are determined from pilot signals and an interpolation process. When the receiver is an OFDM receiver, the pilot signals are advantageously selected to be in clusters that are equally spaced from each other in the time or the frequency domains. This approach applies to multiple antenna, as well as to single antenna arrangements, and to arrangements that do, or do not use space-time coding.
    Type: Grant
    Filed: May 21, 2002
    Date of Patent: October 31, 2006
    Assignee: AT&T Corp.
    Inventors: Naofal Al-Dhahir, Suhas N. Diggavi, Anastasios Stamoulis