Patents by Inventor Rajiv Vijayan
Rajiv Vijayan 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).
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Publication number: 20110302605Abstract: Techniques to seamlessly switch reception between multimedia programs are described. For “continued decoding”, a wireless device continues to receive, decode, decompress, and (optionally) display a current program until overhead information needed to decode the new program is received. For “early decoding”, the wireless device receives a user input and identifies a program with potential for user selection. The wireless device initiates decoding of the identified program, prior to its selection, so that the program can be decompressed and displayed earlier if it is subsequently selected. For time-compensated transmission, a base station transmits video and audio for a program in a manner to account for the difference between audio processing delay and video processing delay at the wireless device. This allows the wireless device to present the audio earlier during a program change, since its processing delay is shorter, and thus provide a faster response to the program change.Type: ApplicationFiled: August 15, 2011Publication date: December 8, 2011Applicant: QUALCOMM IncorporatedInventors: Murali Ramaswamy, Gordon Kent Walker, Rajiv Vijayan
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Patent number: 8045512Abstract: To support mobile stations that are not capable of demodulating the entire bandwidth or that can be made to demodulate less than the entire bandwidth, a system, apparatus and method are provided to schedule users on less than all of the bandwidth. Further, certain users can be scheduled on more of the bandwidth than others.Type: GrantFiled: October 27, 2005Date of Patent: October 25, 2011Assignee: QUALCOMM IncorporatedInventors: Aamod Khandekar, Alexei Gorokhov, Avneesh Agrawal, Rajiv Vijayan, Edward Harrison Teague, Fatih Ulupinar
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Patent number: 8005420Abstract: Techniques to seamlessly switch reception between multimedia programs are described. For “continued decoding”, a wireless device continues to receive, decode, decompress, and (optionally) display a current program, even after a new program has been selected, until overhead information needed to decode the new program is received. After receiving the overhead information, the wireless device decodes the new program but continues to decompress the current program. The wireless device decompresses the new program after decoding this program. For “early decoding”, the wireless device receives a user input and identifies a program with potential for user selection. The identified program may be the one highlighted by the user input or a program anticipated to be selected based on the user input. The wireless device initiates decoding of the identified program, prior to its selection, so that the program can be decompressed and displayed earlier if it is subsequently selected.Type: GrantFiled: May 22, 2007Date of Patent: August 23, 2011Assignee: QUALCOMM IncorporatedInventors: Ramaswamy Murali, Gordon Kent Walker, Rajiv Vijayan
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Patent number: 7907593Abstract: To allow a receiving entity to derive a longer channel estimate while limiting overhead, a transmitting entity transmits a pilot on different groups of subbands in different time intervals. N subbands in the system are arranged into M non-overlapping groups. Each group includes P=N/M subbands that are uniformly distributed across the N subbands. The transmitting entity transmits the pilot on a different subband group in each time interval, and selects all M subband groups in M time intervals based on a pilot staggering pattern. The receiving entity derives (1) an initial impulse response estimate with P channel taps based on the pilot received on one subband group and (2) two longer impulse response estimates with different lengths used for data detection and time tracking. Each longer impulse response estimate may be derived by filtering initial impulse response estimates for a sufficient number of subband groups using a time-domain filter.Type: GrantFiled: October 20, 2008Date of Patent: March 15, 2011Assignee: QUALCOMM IncorporatedInventors: Rajiv Vijayan, Ashok Mantravadi, Krishna Kiran Mukkavilli
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Publication number: 20110058469Abstract: The embodiments utilize OFDM symbols to communicate network IDs. The IDs are encoded into symbols utilizing the network IDs as seeds to scramble respective pilots that are then transmitted by utilizing the symbols. The pilots can be structured into a single OFDM symbol and/or multiple OFDM symbols. The single symbol structure for transmitting the network IDs is independent of the number of network ID bits and minimizes frequency offset and Doppler effects. The multiple symbol structure allows a much coarser timing accuracy to be employed at the expense of transmitting additional symbols. Several embodiments employ a search function to find possible network ID candidates from a transmitted symbol and a selection function to find an optimum candidate from a network ID candidate list.Type: ApplicationFiled: November 18, 2010Publication date: March 10, 2011Applicant: QUALCOMM IncorporatedInventors: Michael Mao Wang, Bojan Vrcelj, Krishna Kiran Mukkavilli, Raghuraman Krishnamoorthi, Rajiv Vijayan
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Patent number: 7881245Abstract: To broadcast different types of transmission having different tiers of coverage in a wireless broadcast network, each base station processes data for a wide-area transmission in accordance with a first mode (or coding and modulation scheme) to generate data symbols for the wide-area transmission and processes data for a local transmission in accordance with a second mode to generate data symbols for the local transmission. The first and second modes are selected based on the desired coverage for wide-area and local transmissions, respectively. The base station also generates pilots and overhead information for local and wide-area transmissions. The data, pilots, and overhead information for local and wide-area transmissions are multiplexed onto their transmission spans, which may be different sets of frequency subbands, different time segments, or different groups of subbands in different time segments. More than two different types of transmission may also be multiplexed and broadcast.Type: GrantFiled: July 20, 2009Date of Patent: February 1, 2011Assignee: QUALCOMM IncorporatedInventors: Rajiv Vijayan, Fuyun Ling, Gordon Kent Walker, Ramaaswamy Murali, Ashok Mantravadi, Anand Subramaniam, Krishnamurthy Viswanathan, legal representative
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Patent number: 7852822Abstract: The embodiments utilize OFDM symbols to communicate network IDs. The IDs are encoded into symbols utilizing the network IDs as seeds to scramble respective pilots that are then transmitted by utilizing the symbols. The pilots can be structured into a single OFDM symbol and/or multiple OFDM symbols. The single symbol structure for transmitting the network IDs is independent of the number of network ID bits and minimizes frequency offset and Doppler effects. The multiple symbol structure allows a much coarser timing accuracy to be employed at the expense of transmitting additional symbols. Several embodiments employ a search function to find possible network ID candidates from a transmitted symbol and a selection function to find an optimum candidate from a network ID candidate list.Type: GrantFiled: December 22, 2004Date of Patent: December 14, 2010Assignee: QUALCOMM IncorporatedInventors: Michael Mao Wang, Bojan Vrcelj, Krishna Kiran Mukkavilli, Raghuraman Krishnamoorthi, Rajiv Vijayan
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Publication number: 20100265865Abstract: 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: ApplicationFiled: May 21, 2007Publication date: October 21, 2010Inventors: Rajiv Vijayan, Aamod Khandekar, Fuyun Ling, Gordon Kent Walker, Ramaswamy Murali
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Patent number: 7796563Abstract: An apparatus for selecting a best serving sector in a code division multiple access (CDMA) communication system. A comparator compares a plurality of signal levels received from a plurality of active sectors with a signal level of a current serving sector to produce a difference. A delta generator is coupled to the comparator that generates a delta credit for each of the plurality of active sectors based on the difference. An accumulator is coupled to the delta generator and accumulates a plurality of delta credits to produce an accumulated total credit. A best sector identifier that is coupled to the accumulator identifies the best serving sector from the accumulated total credit.Type: GrantFiled: November 12, 2003Date of Patent: September 14, 2010Assignee: QUALCOMM IncorporatedInventors: Qiang Wu, Nagabhushana Sindhushayana, Peter J. Black, Rajiv Vijayan, Rashid Attar
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Publication number: 20100220816Abstract: A wireless communication apparatus in a hierarchically coded modulation system can use error control mechanisms generated during decoding of base layer information to predict a probability of successful demodulation of enhancement layer information. Performance in the demodulation of the base layer correlates to performance in the demodulation of the enhancement layer. The receiver can determine whether to attempt demodulation of temporally correlated enhancement layer data based in part on the predicted probability of success. If the receiver determines not to demodulate the enhancement layer, the receiver can power down the enhancement layer demodulator, or otherwise minimize the power expended in the enhancement layer demodulator.Type: ApplicationFiled: May 11, 2010Publication date: September 2, 2010Applicant: QUALCOMM IncorporatedInventors: Gordon Kent Walker, Rajiv Vijayan, Seong Taek Chung, Murali Ramaswamy Chari, Fuyun Ling
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Patent number: 7746760Abstract: Frequency error estimation and frame synchronization are performed at a receiver in an OFDM system based on a metric that is indicative of detected pilot power. The metric may be defined based on cross-correlation between two received symbols obtained in two OFDM symbol periods. For frequency error estimation, a metric value is computed for each of multiple hypothesized frequency errors. The hypothesized frequency error for the metric value with the largest magnitude is provided as the estimated frequency error. For frame synchronization, a correlation value is obtained for each OFDM symbol period by correlating metric values obtained for NC (e.g., most recent) OFDM symbol periods with NC expected values. The expected values are computed in a manner consistent with the manner in which the metric values are computed. Peak detection is performed on the correlation values obtained for different OFDM symbol periods to determine frame synchronization.Type: GrantFiled: January 8, 2004Date of Patent: June 29, 2010Assignee: QUALCOMM IncorporatedInventors: Rajiv Vijayan, Alok Kumar Gupta, Raghuraman Krishnamoorthi
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Patent number: 7725799Abstract: A wireless communication apparatus in a hierarchically coded modulation system can use error control mechanisms generated during decoding of base layer information to predict a probability of successful demodulation of enhancement layer information. Performance in the demodulation of the base layer correlates to performance in the demodulation of the enhancement layer. The receiver can determine whether to attempt demodulation of temporally correlated enhancement layer data based in part on the predicted probability of success. If the receiver determines not to demodulate the enhancement layer, the receiver can power down the enhancement layer demodulator, or otherwise minimize the power expended in the enhancement layer demodulator.Type: GrantFiled: March 31, 2005Date of Patent: May 25, 2010Assignee: QUALCOMM IncorporatedInventors: Gordon Kent Walker, Rajiv Vijayan, Seong Taek Chung, Murali Ramaswamy Chari, Fuyun Ling
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Patent number: 7720027Abstract: Systems and methods are provided for processing forward link only (FLO) signals. A device receives a FLO signal, processes a TDM pilot comprising a TDM Pilot 1, a TDM Pilot 2, a WIC, a LIC, a Transition Pilot Channel, and a Positioning Pilot, from the FLO signal, processes an overhead information symbol (OIS) comprising a wide-area OIS and a local-area OIS, from the FLO signal, processes an FDM pilot comprising a wide-area FDM pilot and a local-area FDM pilot, from the FLO signal; and processes data comprising wide-area data and local-area data, from the FLO signal.Type: GrantFiled: July 27, 2006Date of Patent: May 18, 2010Assignee: QUALCOMM IncorporatedInventors: Fuyun Ling, Murali Ramaswamy Chari, Rajiv Vijayan, Ashok Mantravadi, Alok Kumar Gupta, Krishna Kiran Mukkavilli, Michael Mao Wang, Bojan Vrcelj, Bruce Collins
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Publication number: 20100119005Abstract: A rate adaptive transmission scheme for MIMO systems, which can transmit a variable number of data symbol streams, provide transmit diversity for each data symbol stream, and fully utilize the total transmit power of the system and the full power of each antenna. In one method, at least one data symbol stream is received for transmission from a plurality of antennas. Each data symbol stream is scaled with a respective weight corresponding to the amount of transmit power allocated to that stream. The scaled data symbol stream(s) are multiplied with a transmit basis matrix to provide a plurality of transmit symbol streams for the plurality of antennas. The transmit basis matrix (e.g., a Walsh-Hadamard matrix or a DFT matrix) is defined such that each data symbol stream is transmitted from all antennas and each transmit symbol stream is transmitted at (or near) the full power for the associated antenna.Type: ApplicationFiled: January 20, 2010Publication date: May 13, 2010Applicant: QUALCOMM IncorporatedInventors: Avneesh Agrawal, Rajiv Vijayan, Tamer Kadous
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Publication number: 20100098032Abstract: To broadcast different types of transmission having different tiers of coverage in a wireless broadcast network, each base station processes data for a wide-area transmission in accordance with a first mode (or coding and modulation scheme) to generate data symbols for the wide-area transmission and processes data for a local transmission in accordance with a second mode to generate data symbols for the local transmission. The first and second modes are selected based on the desired coverage for wide-area and local transmissions, respectively. The base station also generates pilots and overhead information for local and wide-area transmissions. The data, pilots, and overhead information for local and wide-area transmissions are multiplexed onto their transmission spans, which may be different sets of frequency subbands, different time segments, or different groups of subbands in different time segments. More than two different types of transmission may also be multiplexed and broadcast.Type: ApplicationFiled: December 23, 2009Publication date: April 22, 2010Applicant: QUALCOMM IncorporatedInventors: Rajiv Vijayan, Fuyun Ling, Gordon Kent Walker, Ramaswamy Murali, Ashok Mantravadi, Anand Subramaniam, Krishnamurthy Viswanathan
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Publication number: 20100067474Abstract: Techniques for managing peak-to-average power ratio (PAPR) for multi-carrier modulation in wireless communication systems. Different terminals in a multiple-access system may have different required transmit powers. The number of carriers to allocate to each terminal is made dependent on its required transmit power. Terminals with higher required transmit powers may be allocated fewer carriers (associated with smaller PAPR) to allow the power amplifier to operate at higher power levels. Terminals with lower required transmit powers may be allocated more carriers (associated with higher PAPR) since the power amplifier is operated at lower power levels. The specific carriers to assign to the terminals may also be determined by their transmit power levels to reduce out-of-band emissions. Terminals with higher required transmit powers may be assigned with carriers near the middle of the operating band, and terminals with lower required transmit powers may be assigned with carriers near the band edges.Type: ApplicationFiled: November 19, 2009Publication date: March 18, 2010Applicant: QUALCOMM IncorporatedInventors: Rajiv Vijayan, Avneesh Agrawal, Sanjay Jha
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Patent number: 7675886Abstract: A rate adaptive transmission scheme for MIMO systems, which can transmit a variable number of data symbol streams, provide transmit diversity for each data symbol stream, and fully utilize the total transmit power of the system and the full power of each antenna. In one method, at least one data symbol stream is received for transmission from a plurality of antennas. Each data symbol stream is scaled with a respective weight corresponding to the amount of transmit power allocated to that stream. The scaled data symbol stream(s) are multiplied with a transmit basis matrix to provide a plurality of transmit symbol streams for the plurality of antennas. The transmit basis matrix (e.g., a Walsh-Hadamard matrix or a DFT matrix) is defined such that each data symbol stream is transmitted from all antennas and each transmit symbol stream is transmitted at (or near) the full power for the associated antenna.Type: GrantFiled: August 16, 2004Date of Patent: March 9, 2010Assignee: QUALCOMM IncorporatedInventors: Avneesh Agrawal, Rajiv Vijayan, Tamer Kadous
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Publication number: 20100046675Abstract: A media access control (MAC) layer controller can manage base layer data and enhancement layer data in a layered modulation system. The MAC layer controller can process both base layer data and enhancement layer data and map the encoded symbols to a layered modulation constellation when both are present. If data for one of the layers terminates, then the MAC layer controller can generate and supply predetermined stuffing data to the layer lacking additional data. The MAC layer controller can send a control signal to the physical layer hardware to cause the hardware to map the layered signals having the stuffing data to a modified signal constellation. The MAC controller can also generate an overhead message that indicates the occurrence of the stuffing data. The receiver can receive the overhead message and can use the information to configure the receiver for the layered modulation constellation or the modified signal constellation.Type: ApplicationFiled: October 28, 2009Publication date: February 25, 2010Applicant: QUALCOMM IncorporatedInventors: Bruce Collins, Rajeev Krishnamurthi, Murali Ramaswamy Chari, Shusheel Gautam, Rajiv Vijayan, Seong Taek Chung
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Patent number: 7660275Abstract: To broadcast different types of transmission having different tiers of coverage in a wireless broadcast network, each base station processes data for a wide-area transmission in accordance with a first mode (or coding and modulation scheme) to generate data symbols for the wide-area transmission and processes data for a local transmission in accordance with a second mode to generate data symbols for the local transmission. The first and second modes are selected based on the desired coverage for wide-area and local transmissions, respectively. The base station also generates pilots and overhead information for local and wide-area transmissions. The data, pilots, and overhead information for local and wide-area transmissions are multiplexed onto their transmission spans, which may be different sets of frequency subbands, different time segments, or different groups of subbands in different time segments. More than two different types of transmission may also be multiplexed and broadcast.Type: GrantFiled: October 18, 2004Date of Patent: February 9, 2010Assignee: QUALCOMM IncorporatedInventors: Rajiv Vijayan, Fuyun Ling, Gordon Kent Walker, Ramaswamy Murali, Ashok Mantravadi, Anand Subramaniam, Krishnamurthy Viswanathan, legal representative
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Publication number: 20090316835Abstract: A wireless communication apparatus in a hierarchically coded modulation system can use error control mechanisms generated during decoding of base layer information to predict a probability of successful demodulation of enhancement layer information. Performance in the demodulation of the base layer correlates to performance in the demodulation of the enhancement layer. The receiver can determine whether to attempt demodulation of temporally correlated enhancement layer data based in part on the predicted probability of success. If the receiver determines not to demodulate the enhancement layer, the receiver can power down the enhancement layer demodulator, or otherwise minimize the power expended in the enhancement layer demodulator.Type: ApplicationFiled: May 17, 2009Publication date: December 24, 2009Applicant: QUALCOMM IncorporatedInventors: Gordon Kent Walker, Rajiv Vijayan, Seong Taek Chung, Murali Ramaswamy Chari, Fuyun Ling