Patents by Inventor Ashok Mantravadi

Ashok Mantravadi 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: 8588203
    Abstract: Techniques to transmit data with cyclic delay diversity and pilot staggering are described. For cyclic delay diversity, OFDM symbols having different cyclic delay durations are generated. The cyclic delay durations for the OFDM symbols may be selected to be time varying with respect to the cyclic delay durations for OFDM symbols transmitted by a neighboring base station. An FDM pilot is generated and multiplexed on multiple sets of subbands in different symbol periods. Waveforms for a second radio technology (e.g., W-CDMA) may be generated for data to be transmitted with this radio technology. The OFDM symbols are multiplexed onto time slots used for OFDM, and the waveforms for the second radio technology are multiplexed onto time slots used for this radio technology. One or multiple modulated signals may be generated based on the multiplexed OFDM symbols and waveforms. Each modulated signal is transmitted from a respective antenna.
    Type: Grant
    Filed: June 2, 2005
    Date of Patent: November 19, 2013
    Assignee: Qualcomm Incorporated
    Inventors: Avneesh Agrawal, Durga Prasad Malladi, Anastasios Stamoulis, Ashok Mantravadi, Ramaswamy Murali
  • Patent number: 8582596
    Abstract: Techniques for transmitting data in a wireless communication system are described. Physical channels to be sent in a super-frame are identified and allocated time slots in the super-frame. The coding and modulation for each physical channel are selected based on its capacity. The data for each physical channel is selectively encoded based on an outer code rate, e.g., for a Reed-Solomon code, and further encoded based on an inner code rate, e.g., for a Turbo code. The encoded data for each physical channel is mapped to modulation symbols based on a selected modulation scheme. The modulation symbols for each physical channel are further processed (e.g., OFDM modulated) and multiplexed onto the time slots allocated to the physical channel. Data to be sent using another radio technology (e.g., W-CDMA) is also processed and multiplexed onto time slots allocated for this radio technology.
    Type: Grant
    Filed: June 2, 2005
    Date of Patent: November 12, 2013
    Assignee: Qualcomm Incorporated
    Inventors: Avneesh Agrawal, Durga Prasad Malladi, Anastasios Stamoulis, Ashok Mantravadi, Ramaswamy Murali
  • Patent number: 8577299
    Abstract: To transmit data in a manner to mitigate the deleterious effects of delay spread, the expected coverage areas for multiple transmissions to be sent in multiple time slots are initially determined. Cyclic prefix lengths for these transmissions are selected based on the expected coverage areas. The cyclic prefix length for each transmission may be selected from among a set of allowed cyclic prefix lengths based on the expected coverage area for that transmission, the pilot staggering used for the transmission, and so on. For example, a shorter cyclic prefix length may be selected for each local transmission, and a longer cyclic prefix length may be selected for each wide-area transmission. The selected cyclic prefix lengths may be signaled to the terminals. The transmissions are processed (e.g., OFDM modulated) based on the selected cyclic prefix lengths. The cyclic prefix lengths may be selected periodically, e.g., in each super-frame.
    Type: Grant
    Filed: June 2, 2005
    Date of Patent: November 5, 2013
    Assignee: Qualcomm Incorporated
    Inventors: Avneesh Agrawal, Durga Prasad Malladi, Anastasios Stamoulis, Ashok Mantravadi, Ramaswamy Murali
  • Patent number: 8571066
    Abstract: Methods and apparatus for RF channel switching in a multi-frequency network. In an aspect, a method includes identifying a multiplex set that comprises one or more content flows, wherein the multiplex set is one of a vertical multiplex (VM) set and a unified multiplex (UM) set, generating an overhead message that associates one or more RF carrier frequencies with the one or more content flows, and transmitting the overhead message over the multi-frequency network. An apparatus includes input logic configured to receive an overhead message that associates one or more content flows with one or more RF carrier frequencies, and processing logic configured to detect a channel switch event that identifies a selected content flow, determine a selected RF carrier frequency associated with the selected content flow based on the overhead message, and switch to the selected RF carrier frequency to receive the selected content flow.
    Type: Grant
    Filed: March 19, 2008
    Date of Patent: October 29, 2013
    Assignee: Qualcomm Incorporated
    Inventors: Binita Gupta, An Mei Chen, Devarshi Shah, Linbo Li, Raghuraman Krishnamoorthi, Ashok Mantravadi, Taoufik Tani
  • Publication number: 20130279355
    Abstract: A method for wireless communications includes determining a time division duplex (TDD) configuration of a non-serving network. The method also includes detecting interference from the non-serving network based at least in part on the TDD configuration of the non-serving network. The method further includes signaling an eNodeB of the interference based at least in part on the detecting.
    Type: Application
    Filed: April 18, 2013
    Publication date: October 24, 2013
    Applicant: QUALCOMM Incorporated
    Inventors: Ahmed Kamel Sadek, Tamer Adel Kadous, Pranav Dayal, Ashok Mantravadi
  • Patent number: 8555136
    Abstract: A receiver includes a decoder configured to decode at least a portion of a data stream comprising a data frame. The data frame includes a code block having a data block and a parity block. The receiver also includes a controller. The controller is configured to determine whether to disable at least a portion of the receiver during transmission of the parity block to the receiver when the data block contains at least one erasure.
    Type: Grant
    Filed: July 25, 2007
    Date of Patent: October 8, 2013
    Assignee: QUALCOMM Incorporated
    Inventors: Soumya Das, Ashok Mantravadi, Ravishanker Mudigonda
  • Patent number: 8553822
    Abstract: Pilot transmission and channel estimation techniques for an OFDM system with excess delay spread are described. To mitigate the deleterious effects of excess delay spread, time filtering is utilized. Time filtering is utilized to combat excess delay spread effects in channel estimation. The time filtering is performed in the presence of staggered pilots and helps in improving the channel estimate in the presence of excess delay spread.
    Type: Grant
    Filed: December 22, 2004
    Date of Patent: October 8, 2013
    Assignee: QUALCOMM Incorporated
    Inventors: Dhananjay Ashok Gore, Ashok Mantravadi, Fuyun Ling, Krishna Kiran Mukkavilli, Raghuraman Krishnamoorthi
  • Patent number: 8542765
    Abstract: Techniques are provided for performing hierarchical coding in a multi-antenna communication system (e.g., a SIMO, MISO, or MIMO system). At a transmitter, a base stream and an enhancement stream are coded and modulated separately to obtain first and second data symbol streams, respectively. The first data symbol stream is processed in accordance with a first spatial processing scheme (e.g., a transmit diversity or a spatial multiplexing scheme) to obtain a first set of symbol substreams. The second data symbol stream is processed in accordance with a second spatial processing scheme (e.g., transmit diversity or spatial multiplexing) to obtain a second set of symbol substreams. The first set of symbol substreams is combined (e.g., using time division multiplexing or superposition) with the second set of symbol substreams to obtain multiple transmit symbol streams for transmission from multiple transmit antennas. A receiver performs complementary processing to recover the base stream and enhancement stream.
    Type: Grant
    Filed: May 11, 2010
    Date of Patent: September 24, 2013
    Assignee: QUALCOMM Incorporated
    Inventors: Ashok Mantravadi, Avneesh Agrawal
  • Publication number: 20130242780
    Abstract: A user equipment (UE) may mitigate coexistence issues in multi-radio devices, where significant in-device coexistence problems can. The UE determines at least one potential virtual gap pattern configuration for a first radio access technology (RAT). The UE also selects one of the at least one potential gap pattern configuration based at least in part on protecting subframes which are used by the first RAT to perform clean signal reference measurements and/or based at least in part on performance of the second RAT. Further, the UE quiets transmit activities of a second RAT during protected subframes of the first RAT in the determined potential virtual gap pattern configuration.
    Type: Application
    Filed: March 11, 2013
    Publication date: September 19, 2013
    Applicant: QUALCOMM INCORPORATED
    Inventors: Pranav Dayal, Ashok Mantravadi
  • Patent number: 8509325
    Abstract: An adaptive thresholding technique eliminates suboptimum threshold values by adjusting for varying channel conditions to eliminate interference where no channel energy is present, without discarding viable taps having useful channel energy. The adaptive thresholding technique adaptively optimizes receive threshold values for both wide and local area channels based only on measured C/I ratios 300. Thresholds are calculated based on instantaneous C/I estimates and/or weighted average C/I estimates calculated from WID/LID energies obtained from the current superframe WIC/LIC symbols respectively. In alternate embodiments, thresholds are calculated based on instantaneous C/I estimates and/or weighted average C/I estimates calculated from WTPC and LTPC symbols for the wide and local area channels, respectively The present adaptive thresholding technique dynamically reduces the threshold as the C/I estimate increases to mitigate performance degradation due to removal of weak signal taps.
    Type: Grant
    Filed: October 13, 2008
    Date of Patent: August 13, 2013
    Assignee: QUALCOMM Incorporated
    Inventors: Ashok Mantravadi, Krishna Kiran Mukkavilli, Raghuraman Krishnamoorthi, Rajeev Krishnamurthi
  • Patent number: 8509051
    Abstract: Techniques for multiplexing and transmitting multiple data streams are described. Transmission of the multiple data streams occurs in “super-frames”. Each super-frame has a predetermined time duration and is further divided into multiple (e.g., four) frames. Each data block for each data stream is outer encoded to generate a corresponding code block. Each code block is partitioned into multiple subblocks, and each data packet in each code block is inner encoded and modulated to generate modulation symbols for the packet. The multiple subblocks for each code block are transmitted in the multiple frames of the same super-frame, one subblock per frame. Each data stream is allocated a number of transmission units in each super-frame and is assigned specific transmission units to achieve efficient packing. A wireless device can select and receive individual data streams.
    Type: Grant
    Filed: October 31, 2007
    Date of Patent: August 13, 2013
    Assignee: QUALCOMM Incorporated
    Inventors: Fuyun Ling, Murali Ramaswamy Chari, Ashok Mantravadi, Raghuraman Krishnamoorthi
  • Publication number: 20130156124
    Abstract: A system and method for frequency diversity uses interleaving in a wireless communication system utilizing orthogonal frequency division multiplexing (OFDM) with various FFT sizes. Subcarriers of one or more interlaces are interleaved in a bit reversal fashion and the one or more interlaces are interleaved in the bit reversal fashion.
    Type: Application
    Filed: February 14, 2013
    Publication date: June 20, 2013
    Applicant: Qualcomm Incorporated
    Inventors: Michael Mao Wang, Murali Ramaswamy Chari, Ashok Mantravadi, Fuyun Ling, Rajiv Vijayan, Raghuraman Krishnamoorthi
  • Publication number: 20130155884
    Abstract: To comport with specific absorption rate (SAR) requirements for a transmitting multi-radio mobile device, transmissions of the multiple radios may be duplexed to ensure compliance with communication regulations. Duplexing of transmissions may occur if overall transmissions exceed a particular threshold value. The duplexing may be opportunistic or deterministic.
    Type: Application
    Filed: September 24, 2012
    Publication date: June 20, 2013
    Inventors: Jibing Wang, Tamer Adel Kadous, Ashok Mantravadi
  • Patent number: 8457064
    Abstract: Methods and apparatus for RF handoff in a multi-frequency network. A method includes generating seamless and partially seamless handoff tables for multiplexes carried in a current LOI, wherein the seamless and partially seamless handoff tables comprise neighboring RF channels carrying one or more of the multiplexes in the current LOI, detecting a handoff event initiated by acquisition failures on a current RF, selecting a selected RF channel from the seamless and partially seamless handoff tables, and performing a handoff to the selected RF channel. An apparatus includes processing logic configured to generate the seamless and partially seamless handoff tables, detect a handoff event initiated by acquisition failures on a current RF, and select a selected RF channel from the seamless and partially seamless handoff tables. The apparatus also includes channel switch logic configured to perform a handoff to the selected RF channel.
    Type: Grant
    Filed: March 19, 2008
    Date of Patent: June 4, 2013
    Assignee: QUALCOMM Incorporated
    Inventors: Binita Gupta, Linbo Li, Raghuraman Krishnamoorthi, Ashok Mantravadi
  • Patent number: 8451776
    Abstract: A method includes identifying coexistence issues among radios in a User Equipment (UE). The method also includes submitting a message to a base station that requests reconfiguring of a timing schedule of a first one of the supported radios to provide for periods of inactivity of the first one of the supported radios. The inactive periods provide operating periods for at least a second one of the supported radios. The inactive periods may be measurement gaps.
    Type: Grant
    Filed: August 5, 2010
    Date of Patent: May 28, 2013
    Assignee: QUALCOMM Incorporated
    Inventors: Pranav Dayal, Ashok Mantravadi, Tamer Adel Kadous, Parag Arun Agashe
  • Patent number: 8443255
    Abstract: A method of generating a parity check matrix for iterative decoding of a linear block code includes: determining a set of parity check vectors for the linear block code; ordering according to Hamming weight non-zero parity check vectors of the set; selecting a criterion for generating the parity check matrix; and building the parity check matrix by incrementally selecting according to the criterion a parity check vector for each consecutive row of the parity check matrix, wherein the parity check vector is selected from the ordered non-zero parity check vectors remaining in the set.
    Type: Grant
    Filed: August 26, 2010
    Date of Patent: May 14, 2013
    Assignee: Qualcomm Incorporated
    Inventors: Jing Jiang, Tao Tian, Raghuraman Krishnamoorthi, Xinmiao Zhang, Ashok Mantravadi, Krishna Mukkavilli
  • Patent number: 8442160
    Abstract: Time filtering channel estimates in a wireless communication system, such as an Orthogonal Frequency Division Multiplex (OFDM) system, can be used to improve the quality of channel estimates. The characteristics of an optimal channel estimate time filter can depend on the manner in which the channel estimate is determined as well as the time correlation of channel estimates. A receiver can implement an adaptive time filter for channel estimates in which the time filter response can vary based on channel estimate parameters. The channel estimate parameters can include the manner of determining channel estimates, a time correlation of channel estimates, and an estimated Doppler frequency. The time filter response can be varied continuously over a range of responses or can be varied discretely over a predetermined number of time filter responses.
    Type: Grant
    Filed: November 3, 2010
    Date of Patent: May 14, 2013
    Assignee: Qualcomm Incorporated
    Inventors: Linbo Li, Ashok Mantravadi, Fuyun Ling, Krishna Kiran Mukkavilli
  • Patent number: 8441913
    Abstract: Systems and methods are provided for enhancing signal quality at receivers in a wireless network. In one embodiment, an antenna is selected from a subset of antennas based on a signal quality parameter such as received signal power or signal-to-noise ratio (SNR). In another embodiment, multiple antennas are applied to independent signal processing paths for the respective antennas where output from the paths is then combined to enhance overall signal quality at the receiver.
    Type: Grant
    Filed: September 15, 2006
    Date of Patent: May 14, 2013
    Assignee: Qualcomm Incorporated
    Inventors: Linbo Li, Ashok Mantravadi, Fuyun Ling
  • Publication number: 20130107868
    Abstract: A method for mitigating the impact of a power imbalance on a remote data rate in a wireless local area network (WLAN) includes transmitting a wireless local area network (WLAN) acknowledgement (ACK) packet at a first transmit power level to a remote device. The method further includes transmitting, to the remote device, a WLAN data packet at a second transmit power level that is lower than the first transmit power level of the WLAN ACK packet. Another method for mitigating the impact of a power imbalance on a remote data rate in a wireless local area network (WLAN) may include selecting a wireless local area network (WLAN) acknowledgement (ACK) packet transmit rate independent from a rate at which a WLAN data packet is received. This method further includes transmitting, to a remote device, a WLAN ACK packet at the selected WLAN ACK packet transmit rate.
    Type: Application
    Filed: July 12, 2012
    Publication date: May 2, 2013
    Applicant: Qualcomm Incorporated
    Inventors: Ahmed K. Sadek, Ashok Mantravadi, Tamer Adel Kadous
  • Patent number: 8433016
    Abstract: The disclosure is directed to a receiver, and methods therefor, including an automatic gain control circuit with a first digital variable gain amplifier that outputs digital samples based on a modulated wireless signal, an interference canceller configured to filter the digital samples using a least mean squares algorithm to reduce narrowband interference, and a second DVGA configured to amplify the filtered digital samples.
    Type: Grant
    Filed: May 14, 2010
    Date of Patent: April 30, 2013
    Assignee: Qualcomm Incorporated
    Inventors: Bojan Vrcelj, Ashok Mantravadi, Fuyun Ling, Linbo Li, Raghuraman Krishnamoorthi, Murali Ramaswamy Chari, Vinay Murthy