Patents by Inventor Shivratna G. Srinivasan

Shivratna G. Srinivasan 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: 9603097
    Abstract: An apparatus and method for processing signals are disclosed. The apparatus may include a transceiver configured to receive a first paging signal during a first cycle, a memory, and a processor configured to store the received first paging signal in the memory, to switch the transceiver to an off state after the first paging signal is stored in the memory, to process the stored first paging signal while the transceiver is in the off state, and to determine whether to enter an online mode based on the processing.
    Type: Grant
    Filed: June 29, 2009
    Date of Patent: March 21, 2017
    Assignee: QUALCOMM Incorporated
    Inventors: Supratik Bhattacharjee, Brian C. Banister, Shivratna G. Srinivasan
  • Patent number: 9071493
    Abstract: Methods and apparatus for correcting frequency errors between a carrier frequency of a signal received by a wireless device and a reference frequency local to the device. For certain aspects, such a method generally includes receiving a signal in a receiver having an LO producing a reference frequency, a radio frequency (RF) phase-locked loop (PLL), and a digital rotator, estimating a frequency difference between a carrier frequency of the received signal and the LO reference frequency, and applying the estimated frequency difference to the RF PLL and the digital rotator.
    Type: Grant
    Filed: June 28, 2010
    Date of Patent: June 30, 2015
    Assignee: QUALCOMM Incorporated
    Inventors: Brian C. Banister, Shivratna G. Srinivasan, Matthias Brehler, Sunil Kumar Kandukuri Narayana, Raghu N. Challa
  • Patent number: 8554251
    Abstract: An apparatus and method for processing signals are disclosed. The apparatus may include a transceiver configured to receive a first paging signal during a first cycle, a memory, and a processor configured to store the received first paging signal in the memory, to switch the transceiver to an off state after the first paging signal is stored in the memory, and to process the stored first paging signal while the transceiver is in the off state.
    Type: Grant
    Filed: June 29, 2009
    Date of Patent: October 8, 2013
    Assignee: QUALCOMM Incorporated
    Inventors: Supratik Bhattacharjee, Joseph C. Chan, Brian C. Banister, Shivratna G. Srinivasan
  • Publication number: 20130155883
    Abstract: Techniques for performing a frequency scan to detect wireless systems operating on frequency channels with variable bandwidths are disclosed. In one aspect, a user equipment (UE) performs a frequency scan for a plurality of frequency channels and measures the received power of each frequency channel based on a center frequency and a bandwidth of the frequency channel. The UE identifies candidate frequency channels for acquisition based on the results of the frequency scan. In another aspect, a frequency scan of a band is performed by partitioning the band into multiple segments, measuring received powers of subcarriers or raster frequencies within each segment, and concatenating received powers of subcarriers or raster frequencies for all segments. A frequency scan is then performed based on the concatenated results for the multiple segments.
    Type: Application
    Filed: September 11, 2012
    Publication date: June 20, 2013
    Applicant: QUALCOMM Incorporated
    Inventors: Supratik Bhattacharjee, Shivratna G. Srinivasan, Brian C. Banister, Hisham Mahmoud
  • Publication number: 20130107785
    Abstract: A method, an apparatus, and a computer program product for wireless communication are provided for maintaining a time tracking loop (TTL) to increase an overall signal-to-noise ratio (SNR) of a signal. The signal includes a series of consecutive symbols, received via multiple signal paths with different delays in a subframe. When attempting to decode the signal, only part of a symbol for a signal path may be captured in a fast Fourier transform (FFT) window due to the multiple signal path delays, leading to inter-channel interference (ICI), inter-symbol interference (ISI), and/or power loss. The SNR may be increased by optimizing a FFT window position when decoding the signal. An optimal FFT window position may be based on a subframe type. Moreover, the SNR may be increased by performing a linear operation on samples of the symbol prior to performing the FFT.
    Type: Application
    Filed: April 13, 2012
    Publication date: May 2, 2013
    Applicant: QUALCOMM Incorporated
    Inventors: Kapil Bhattad, Tao Luo, Taesang Yoo, Shivratna G. Srinivasan
  • Patent number: 8416733
    Abstract: Techniques for performing time tracking in a communication system utilizing a cyclic prefix are described. In an aspect, a receiver may detect for large timing errors based on early and late received samples obtained with early and late FFT windows, respectively. The receiver may derive first and second channel impulse response (CIR) estimates based on the early and late received samples, respectively, determine an early channel energy based on the first CIR estimate, determine a late channel energy based on the second CIR estimate, compute an update amount based on the early and late channel energies, and update the FFT window position based on the update amount. In another aspect, the receiver may perform time tracking with an inner time tracking loop (TTL) and an outer TTL. The receiver may update the FFT window position in coarse steps with the outer TTL and in fine steps with the inner TTL.
    Type: Grant
    Filed: June 28, 2010
    Date of Patent: April 9, 2013
    Assignee: QUALCOMM Incorporated
    Inventors: Shivratna G. Srinivasan, Michael L. McCloud, Remi J. Gurski, Sunil Kumar Kandukuri Narayana
  • Publication number: 20110158342
    Abstract: Techniques for performing time tracking in a communication system utilizing a cyclic prefix are described. In an aspect, a receiver may perform time tracking and determine an FFT window position based on a metric related to inter-symbol interference (ISI) and inter-carrier interference (ICI). The receiver may determine an early energy for signal paths earlier than the current FFT window position, determine a late energy for signal paths later than the current FFT window position, determine the metric based on the early and late energies, compute an update amount for the FFT window position based on the metric, and update the FFT window position based on the update amount with a time tracking loop (TTL). In yet another aspect, the receiver may compute the FFT window position based on a channel impulse response (CIR) estimate directly, without using a TTL.
    Type: Application
    Filed: June 28, 2010
    Publication date: June 30, 2011
    Applicant: QUALCOMM Incorporated
    Inventors: Shivratna G. Srinivasan, Michael L. McCloud, Matthias Brehler, Brian Clarke Banister
  • Publication number: 20110158367
    Abstract: Methods and apparatus for correcting frequency errors between a carrier frequency of a signal received by a wireless device and a reference frequency local to the device. For certain aspects, such a method generally includes receiving a signal in a receiver having an LO producing a reference frequency, a radio frequency (RF) phase-locked loop (PLL), and a digital rotator, estimating a frequency difference between a carrier frequency of the received signal and the LO reference frequency, and applying the estimated frequency difference to the RF PLL and the digital rotator.
    Type: Application
    Filed: June 28, 2010
    Publication date: June 30, 2011
    Applicant: QUALCOMM Incorporated
    Inventors: Brian C. Banister, Shivratna G. Srinivasan, Matthias Brehler, Sunil Kumar Kandukuri Narayana, Raghu N. Challa
  • Publication number: 20110149943
    Abstract: Techniques for performing time tracking in a communication system utilizing a cyclic prefix are described. In an aspect, a receiver may detect for large timing errors based on early and late received samples obtained with early and late FFT windows, respectively. The receiver may derive first and second channel impulse response (CIR) estimates based on the early and late received samples, respectively, determine an early channel energy based on the first CIR estimate, determine a late channel energy based on the second CIR estimate, compute an update amount based on the early and late channel energies, and update the FFT window position based on the update amount. In another aspect, the receiver may perform time tracking with an inner time tracking loop (TTL) and an outer TTL. The receiver may update the FFT window position in coarse steps with the outer TTL and in fine steps with the inner TTL.
    Type: Application
    Filed: June 28, 2010
    Publication date: June 23, 2011
    Applicant: QUALCOMM Incorporated
    Inventors: Shivratna G. Srinivasan, Michael L. McCloud, Remi J. Gurski, Sunil Kumar Kandukuri Narayana
  • Publication number: 20100331019
    Abstract: An apparatus and method for processing signals are disclosed. The apparatus may include a transceiver configured to receive a first paging signal during a first cycle, a memory, and a processor configured to store the received first paging signal in the memory, to switch the transceiver to an off state after the first paging signal is stored in the memory, and to process the stored first paging signal while the transceiver is in the off state.
    Type: Application
    Filed: June 29, 2009
    Publication date: December 30, 2010
    Inventors: Supratik Bhattacharjee, Joseph C. Chan, Brian C. Banister, Shivratna G. Srinivasan
  • Publication number: 20100330992
    Abstract: An apparatus and method for processing signals are disclosed. The apparatus may include a transceiver configured to receive a first paging signal during a first cycle, a memory, and a processor configured to store the received first paging signal in the memory, to switch the transceiver to an off state after the first paging signal is stored in the memory, to process the stored first paging signal while the transceiver is in the off state, and to determine whether to enter an online mode based on the processing.
    Type: Application
    Filed: June 29, 2009
    Publication date: December 30, 2010
    Inventors: Supratik Bhattacharjee, Brian C. Banister, Shivratna G. Srinivasan