Patents by Inventor Balaji Raghothaman

Balaji Raghothaman 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: 20050064908
    Abstract: Apparatus, and an associated method, for facilitating communication of encoded data, formed of a systematic part and a non-systematic part, in a radio communication system. Systematic parts of the encoded data are assigned by an assignor to transmit antennas that are associated with communication channels exhibiting better, or best, communication quality levels. Determinations are made of communication conditions to rank the transmit antennas, thereby permit appropriate assignments of the encoded data to transmit antennas. Feedback is provided by the receiver that receives the transmitted data. The feedback information includes, or is formed responsive to, detections and other measurements at the receivers.
    Type: Application
    Filed: September 23, 2003
    Publication date: March 24, 2005
    Inventors: Adrian Boariu, Balaji Raghothaman
  • Patent number: 6842632
    Abstract: Apparatus, and an associated method, for facilitating selection of optimal antenna weightings by which to weight signals sent in a communication system that utilizes closed-loop transmit diversity. A deterministic perturbation gradient approximation technique is utilized in which perturbation vectors are selected by a selector and applied, by an applicator, to antenna weighting elements. A selected set of perturbation vectors are applied to the antenna weighting elements in both a positive direction and a negative direction. A detector at a receiving station measures in disassociated with the signals communicated thereto, once weighted with the perturbation vectors. A single-bit feedback value is returned to the sending station, and the antenna weightings are appropriately adjusted. The technique is utilized during both non-handoff conditions and during handoff conditions.
    Type: Grant
    Filed: December 30, 2002
    Date of Patent: January 11, 2005
    Assignee: Nokia Corporation
    Inventors: Balaji Raghothaman, R. Thomas Derryberry
  • Publication number: 20040266471
    Abstract: A method for scheduling weighted transmissions from two or more transmit antennas of a base station to each of two or more mobile stations in a closed-loop transmit diversity system, whereby the quantity of power available for data transmission from each transmit antenna is determined and, with respect to each antenna, the power required to transmit data to each mobile station is determined. The number of mobile stations that may be served simultaneously by a base station is determined and, for each combination of respective mobile stations constituting the number of mobile stations that may be served simultaneously, the transmission of data from each transmit antenna to the mobile stations is scheduled to minimize unused power.
    Type: Application
    Filed: June 30, 2003
    Publication date: December 30, 2004
    Applicant: Nokia Corporation
    Inventors: Adrian Boariu, Balaji Raghothaman
  • Publication number: 20040223480
    Abstract: Disclosed is a minimum mean square error (MMSE) equalizer and method for single-user detection of a signal received from a downlink code-division multiple access CDMA channel. The equalizer includes a Kalman filter having an input coupled to the received signal for generating a best linear unbiased estimate of a transmitted chip sequence for a single user. A reduced computational complexity Kalman filter embodiment is also disclosed that only periodically updates a Kalman filter prediction error covariance matrix P(k|k−1), a Kalman filter filtering error covariance matrix P(k|k) and the Kalman gain K(k).
    Type: Application
    Filed: May 6, 2003
    Publication date: November 11, 2004
    Applicant: Nokia Corporation
    Inventors: Hoang Nguyen, Jianzhong Zhang, Balaji Raghothaman
  • Publication number: 20040198228
    Abstract: Apparatus, and an associated method, for facilitating selection of optimal antenna weightings by which to weight signals sent in a communication system that utilizes closed-loop transmit diversity. A deterministic perturbation gradient approximation technique is utilized in which perturbation vectors are selected by a selector and applied, by an applicator, to antenna weighting elements. A selected set of perturbation vectors are applied to the antenna weighting elements in both a positive direction and a negative direction. A detector at a receiving station measures in disassociated with the signals communicated thereto, once weighted with the perturbation vectors. A single-bit feedback value is returned to the sending station, and the antenna weightings are appropriately adjusted.
    Type: Application
    Filed: April 26, 2004
    Publication date: October 7, 2004
    Inventor: Balaji Raghothaman
  • Publication number: 20040127257
    Abstract: Apparatus, and an associated method, for facilitating selection of optimal antenna weightings by which to weight signals sent in a communication system that utilizes closed-loop transmit diversity. A deterministic perturbation gradient approximation technique is utilized in which perturbation vectors are selected by a selector and applied, by an applicator, to antenna weighting elements. A selected set of perturbation vectors are applied to the antenna weighting elements in both a positive direction and a negative direction. A detector at a receiving station measures in disassociated with the signals communicated thereto, once weighted with the perturbation vectors. A single-bit feedback value is returned to the sending station, and the antenna weightings are appropriately adjusted. The technique is utilized during both non-handoff conditions and during handoff conditions.
    Type: Application
    Filed: December 30, 2002
    Publication date: July 1, 2004
    Inventors: Balaji Raghothaman, R. Thomas Derryberry
  • Patent number: 6745009
    Abstract: Apparatus, and an associated method, for facilitating selection of optimal antenna weightings by which to weight signals sent in a communication system that utilizes closed-loop transmit diversity. A deterministic perturbation gradient approximation technique is utilized in which perturbation vectors are selected by a selector and applied, by an applicator, to antenna weighting elements. A selected set of perturbation vectors are applied to the antenna weighting elements in both a positive direction and a negative direction. A detector at a receiving station measures in disassociated with the signals communicated thereto, once weighted with the perturbation vectors. A single-bit feedback value is returned to the sending station, and the antenna weightings are appropriately adjusted.
    Type: Grant
    Filed: May 15, 2002
    Date of Patent: June 1, 2004
    Assignee: Nokia Corporation
    Inventor: Balaji Raghothaman
  • Patent number: 6728307
    Abstract: An adaptive transmit antenna array having a reduced pilot set is disclosed. The adaptive transmit antenna array utilizes a decision-directed mechanism for the estimation of maximal ratio combining (MRC) weights to be used at a receiver rather than requiring a user-specific pilot to provide estimation information.
    Type: Grant
    Filed: May 5, 2000
    Date of Patent: April 27, 2004
    Assignee: Nokia Mobile Phones Ltd
    Inventors: R. Thomas Derryberry, Balaji Raghothaman
  • Publication number: 20040067738
    Abstract: Apparatus, and an associated method, for facilitating communications in a non-ideal communication system. Data to be communicated by a sending station to a receiving station selectably utilizes an open-loop transmit diversity scheme and a closed-loop transmit diversity scheme. A determiner at the receiving station determines closed-loop feedback information and a determiner thereat also determines the reliability to be associated with such feedback information. The reliability indications and the feedback indications are returned to the sending station. And a selector positioned thereat selects in what manner to utilize open-loop and closed-loop transmit diversity for subsequent communications.
    Type: Application
    Filed: September 30, 2002
    Publication date: April 8, 2004
    Inventor: Balaji Raghothaman
  • Publication number: 20030215006
    Abstract: Apparatus, and an associated method, for facilitating selection of optimal antenna weightings by which to weight signals sent in a communication system that utilizes closed-loop transmit diversity. A deterministic perturbation gradient approximation technique is utilized in which perturbation vectors are selected by a selector and applied, by an applicator, to antenna weighting elements. A selected set of perturbation vectors are applied to the antenna weighting elements in both a positive direction and a negative direction. A detector at a receiving station measures in disassociated with the signals communicated thereto, once weighted with the perturbation vectors. A single-bit feedback value is returned to the sending station, and the antenna weightings are appropriately adjusted.
    Type: Application
    Filed: May 15, 2002
    Publication date: November 20, 2003
    Inventor: Balaji Raghothaman
  • Publication number: 20030162567
    Abstract: Apparatus, and an associated method, for facilitating selection of antenna pattern characteristics to be exhibited by an antenna assembly of a communication station, such as a base transceiver station operable in a cellular communication system. Indications of channel conditions on an uplink channel are utilized in the determination of antenna weighting values by which to weight antenna weighting elements of the antenna assembly. In one implementation, an uplink channel correlation matrix is reformulated into vector form to reduce the computational complexity of calculations required to select the antenna weighting values. In another implementation, a discrete Fourier transform operation is performed using fast Fourier transform techniques to select the antenna weighting values.
    Type: Application
    Filed: February 22, 2002
    Publication date: August 28, 2003
    Inventors: Balaji Raghothaman, Shu-Shaw Wang
  • Publication number: 20030003873
    Abstract: Apparatus, and associated method, verifies values of antenna weightings used to weight transmit signals transmitted by a base transceiver station which utilizes transmit diversity. Verification is performed at a mobile station which receives transmit signals sent by the base transceiver station. Sequence estimation is provided by a sequence estimator which thereby verifies the values of the feedback information. Once verified, the values are returned to the base transceiver station and are utilized to adjust the weightings of the antennas for subsequently-communicated signals by the base station. The use of sequence estimation permits improved accuracy of verification of the values of the antenna weightings.
    Type: Application
    Filed: June 29, 2001
    Publication date: January 2, 2003
    Inventor: Balaji Raghothaman
  • Publication number: 20020128026
    Abstract: A system and method are provided for reducing the time delay associated with compensating for fading effects. The system includes a base station and a mobile station in communication. The base station transmits information and a pilot signal to the mobile station through each of the channels. The mobile station receives the information as noisy information and the pilot signal as a noisy pilot signal from each of the channels and compares the received noisy pilot signals to determine and predict a weight to be assigned to each of the channels. The calculated predicted weights are transmitted from the mobile station back to the base station as predicted feedback information that is utilized by the base station to alter the characteristics of the modulated carrier signal prior to transmission.
    Type: Application
    Filed: June 29, 2001
    Publication date: September 12, 2002
    Inventors: Roy Thomas Derryberry, Dumitru Mihai Ionescu, Balaji Raghothaman