Patents by Inventor Nitin Kasturi
Nitin Kasturi 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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Patent number: 7599706Abstract: Various embodiments are provided for determining a set of acceptable transport format combinations for transmission on a current time frame. A set of acceptable modified rate power adjustment values is determined based on a maximum power level, an accumulated power commands and an initial power control command. A set of acceptable channel gain factors is determined based on the set of acceptable modified rate power adjustments values, and the set of acceptable transport format combinations is determined based on the set of acceptable channel gain factors. A possible set of modified rate power adjustment values is associated to a set of channel gain factors for determining the set of acceptable channel gain factors based on various design of a transmitter chain used for transmission of data from the mobile station.Type: GrantFiled: December 10, 2004Date of Patent: October 6, 2009Assignee: QUALCOMM IncorporatedInventors: Yi Zhang, Nitin Kasturi, Alkinoos Hector Vayanos, Subramanya P. N. Rao
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Publication number: 20090203339Abstract: Disclosed are methods and apparatus for predicting a channel quality indicator in a communication system, and in particular a delayed receiver. A disclosed method for determining the predictive channel quality indicator for a delayed receiver includes determining at least one channel quality indicator from a non-delayed receiver. The method also includes determining another channel quality indicator from the delayed receiver, and then calculating the predictive channel quality indicator for the delayed receiver through a function of the channel quality indicators from the non-delayed receiver and the channel quality indicator from the delayed receiver. Corresponding apparatus are also disclosed.Type: ApplicationFiled: April 25, 2008Publication date: August 13, 2009Applicant: QUALCOMM INCORPORATEDInventors: Gokhan Mergen, Manini S. Shah, Nathaniel Lev Grossman, Nitin Kasturi, Yan Li
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Patent number: 7363010Abstract: Techniques for controlling transmit power for a data transmission sent on multiple data channels, which may be intermittently active, are described. Each data channel is monitored for activity (e.g., based on an error correction code, received signaling information, received block energy, and so on) and deemed to be dormant or not dormant (e.g., based on the amount of elapsed time since activity was last detected on the data channel). A signal quality (SIR) target may be maintained for each non-dormant data channel and updated based on the status of received data blocks for the data channel. A final SIR target, used for power control of the data transmission, may be set to the highest SIR target among the SIR targets for the non-dormant data channels. The final SIR target may also be updated directly based on the status of received data blocks for the non-dormant data channels.Type: GrantFiled: April 15, 2004Date of Patent: April 22, 2008Assignee: QUALCOMM IncorporatedInventors: Hyukjun Oh, Parvathanathan Subrahmanya, Nitin Kasturi
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Publication number: 20080075147Abstract: In general, this disclosure describes techniques for demodulating wireless signals. In particular, the techniques of this disclosure dynamically select between two or more demodulators based on channel quality information measured over a plurality of measurement periods. For example, a wireless communication device (WCD) may switch from a first demodulator to a second demodulator when the channel quality information associated with the demodulators indicates a better channel quality for the second demodulator than the first demodulator for a consecutive number of measurement periods. As another example, the WCD may compute, for each measurement period, the difference between the channel quality information associated with each of the demodulators, sum the differences, and switch demodulators when the total accumulation of the differences exceeds a threshold.Type: ApplicationFiled: February 27, 2007Publication date: March 27, 2008Inventors: Nathaniel Lev Grossman, Gokhan Mergen, Nitin Kasturi
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Patent number: 7340268Abstract: The reliability of transmit power control (TPC) commands received from a transmitter is determined based on a TPC target value. The TPC target value is derived based on a TPC threshold and possibly a weight, depending on the receiver implementation. A received TPC command is considered reliable if its absolute value exceeds the TPC target value. Received TPC commands deemed as unreliable are discarded and not used for power control. Multiple TPC target values, used for detecting UP and DOWN commands, may be derived with multiple scaling factors. For a receiver in soft handover and receiving TPC commands from multiple transmitters, a different TPC target value may be derived for each transmitter. The received TPC commands for each transmitter are compared against that transmitter's TPC target value. Received TPC commands deemed as unreliable are discarded and not combined.Type: GrantFiled: June 10, 2003Date of Patent: March 4, 2008Assignee: QUALCOMM IncorporatedInventors: Hyukjun Oh, Parvathanathan Subrahmanya, Nitin Kasturi, Messay Amerga, Chih-Ping Hsu, Christopher C. Riddle, Andrew Sendonaris
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Patent number: 7319852Abstract: An apparatus for coarse compensation of a direct current (DC) offset in a direct to baseband receiver architecture utilizes a serial analog to digital converter (ADC), such as a Delta-Sigma converter, to convert the received signal to digital form. The output of the ADC is sampled for a predetermined number of samples and a counter coupled to the ADC is incremented each time the sample generated by the ADC is a logic one. The counter is not incremented if the sample from the ADC is a logic zero. After the predetermined number of samples is obtained, the counter value is indicative of the DC offset in the received signal. The counter value may be converted by a code converter to a correction value for easy operation of a digital to analog converter (DAC). If the number of samples from the ADC is a power of two, the code converted may be readily implemented by simply inverting the most significant bit (MSB) from the counter to thereby generate a twos complement version of the counter value.Type: GrantFiled: August 29, 2002Date of Patent: January 15, 2008Assignee: QUALCOMM, IncorporatedInventors: Nikolai Schlegel, Christian Holenstein, Daniel Filipovic, Nitin Kasturi
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Publication number: 20070218935Abstract: Techniques for power control that avoids outer loop wind-up are disclosed. In one aspect, wind-up of a target power level is detected, and the target power level is modified in response. In another aspect, unwinding of the target power level is detected, after which the target power level is determined without considering wind-up. Various other aspects are also presented, including wind-up and unwinding detection procedures, and target power level modification procedures. These aspects have the benefit of reducing the time that transmit power exceeds that which is necessary, thus increasing system capacity and performance, and mitigating misallocation of system resources.Type: ApplicationFiled: May 18, 2007Publication date: September 20, 2007Applicant: QUALCOMM INCORPORATEDInventors: Richard Chi, Da-Shan Shiu, Nitin Kasturi, Parvathanathan Subrahmanya
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Publication number: 20070110201Abstract: Techniques for filtering noisy estimates to reduce estimation errors are described. A sequence of input values (e.g., for an initial channel impulse response estimate (CIRE)) is filtered with an infinite impulse response (IIR) filter having at least one coefficient to obtain a sequence of output values (e.g., for a filtered CIRE). The coefficient(s) are updated based on the sequence of input values with an adaptive filter, a bank of prediction filters, or a normalized variation technique. To update the coefficient(s) with the adaptive filter, a sequence of predicted values is derived based on the sequence of input values. Prediction errors between the sequence of predicted values and the sequence of input values are determined and filtered to obtain filtered prediction errors. The coefficient(s) of the IIR filter are then updated based on the prediction errors and the filtered prediction errors.Type: ApplicationFiled: July 18, 2006Publication date: May 17, 2007Inventors: Gokhan Mergen, Parvathanathan Subrahmanya, Vijayaraj Alilaghatta-Kantharaj, Nitin Kasturi
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Publication number: 20070110200Abstract: Techniques for performing equalization at a receiver are described. In an aspect, equalization is performed by sub-sampling an over-sampled input signal to obtain multiple sub-sampled signals. An over-sampled channel impulse response estimate is derived and sub-sampled to obtain multiple sub-sampled channel impulse response estimates. At least one set of equalizer coefficients is derived based on at least one sub-sampled channel impulse response estimate. At least one sub-sampled signal is filtered with the at least one set of equalizer coefficients to obtain at least one output signal. One sub-sampled signal (e.g., with largest energy) may be selected and equalized based on a set of equalizer coefficients derived from an associated sub-sampled channel impulse response estimate. Alternatively, the multiple sub-sampled signals may be equalized based on multiple sets of equalizer coefficients, which may be derived separately or jointly.Type: ApplicationFiled: April 7, 2006Publication date: May 17, 2007Inventors: Gokhan Mergen, Parvathananthan Subrahmanya, Nitin Kasturi, Rajesh Sundaresan
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Publication number: 20070110127Abstract: Techniques for deriving a channel impulse response estimate (CIRE) having improved quality are described. A first CIRE with multiple channel taps is obtained based on (1) an initial CIRE derived from a received pilot or (2) a filtered CIRE derived from the initial CIRE. In one aspect, the channel taps in the first CIRE are scaled with multiple scaling factors to obtain a second CIRE. For point-wise LMMSE scaling, the energy of each channel tap is estimated. The noise energy for the channel taps is also estimated, e.g., based on energies of channel taps on one or both edges of the first CIRE. Each channel tap is scaled based on a scaling factor determined by the energy of that channel tap and the noise energy. Each channel tap with energy below a threshold may be set to zero. In another aspect, the second CIRE is obtained by zeroing out selected ones of the channel taps in the first CIRE.Type: ApplicationFiled: April 7, 2006Publication date: May 17, 2007Inventors: Gokhan Mergen, Vignesh Sethuraman, Nitin Kasturi, Parvathanathan Subrahmanya
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Publication number: 20060189342Abstract: Techniques for power control that avoids outer loop wind-up are disclosed. In one aspect, wind-up of a target power level is detected, and the target power level is modified in response. In another aspect, unwinding of the target power level is detected, after which the target power level is determined without considering wind-up. Various other aspects are also presented, including wind-up and unwinding detection procedures, and target power level modification procedures. These aspects have the benefit of reducing the time that transmit power exceeds that which is necessary, thus increasing system capacity and performance, and mitigating misallocation of system resources.Type: ApplicationFiled: November 1, 2005Publication date: August 24, 2006Inventors: Richard Chi, Da-Shan Shiu, Nitin Kasturi, Parvathanathan Subrahmanya
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Patent number: 7012911Abstract: Techniques for efficient W-CDMA modulation are disclosed. In one aspect, a multiplexing/coding chain for use in modulation such as that defined by the W-CDMA specification is disclosed. In another aspect, transport blocks are processed and concatenated, utilizing memory efficiently. This aspect has the further benefit of preparing transport channels for efficient subsequent processing. It also allows for ease of interface with the transport channel source. In another aspect, the use of repeated channel coding is used in lieu of an interleaver memory to provide channel coding and interleaving. These aspects, collectively, yield the advanced benefits of a system, such as W-CDMA, in a hardware efficient manner. The techniques described herein apply equally to both access points and access terminals. The techniques are not limited to W-CDMA systems; they are quite suitable to other systems requiring the various benefits the invention offers. Various other aspects of the invention are also presented.Type: GrantFiled: May 31, 2001Date of Patent: March 14, 2006Assignee: Qualcomm Inc.Inventors: Nitin Kasturi, Rajat Rajinderkumar Dhawan, Daisuke Terasawa, Avneesh Agrawal, Arak Sutivong
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Publication number: 20060050798Abstract: An apparatus, system, and method efficiently manage transmission power in a user equipment (UE) device by maintaining and applying an authorized power level to determine a transmission power level after a power limited transmission and before a new power control command has been received. The UE device maintains the authorized power level by monitoring and adjusting the authorized power level based on received power control commands. After a power limited transmission where the maximum power level is less than the authorized power level, the UE device determines the transmission power level for the next transmission based on the authorized power level. Accordingly, after the power limiting situation has ceased, the UE device transmits at the optimum power level eliminating the inefficiencies of transmitting at a lower than authorized power before the next power control command is received.Type: ApplicationFiled: August 31, 2005Publication date: March 9, 2006Inventors: Erumusele Odigie, Nitin Kasturi, Parvathanathan Subrahmanya
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Patent number: 7010321Abstract: Techniques for power control that avoids outer loop wind-up are disclosed. In one aspect, wind-up of a target power level is detected, and the target power level is modified in response. In another aspect, unwinding of the target power level is detected, after which the target power level is determined without considering wind-up. Various other aspects are also presented, including wind-up and unwinding detection procedures, and target power level modification procedures. These aspects have the benefit of reducing the time that transmit power exceeds that which is necessary, thus increasing system capacity and performance, and mitigating misallocation of system resources.Type: GrantFiled: February 4, 2002Date of Patent: March 7, 2006Assignee: Qualcomm Inc.Inventors: Richard Chi, Da-Shan Shiu, Nitin Kasturi, Parvathanathan Subrahmanya
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Publication number: 20050249149Abstract: Techniques to mitigate spikes in transmit power, by reducing the magnitude and/or duration of the spikes, are described. Initially, power control is performed in a normal manner and in accordance with a transmit power control (TPC) scheme. If a (e.g., upward) transmit power spike is detected, the power control is performed in a manner to mitigate the adverse effects of the spike and in accordance with another TPC scheme. An upward transmit power spike may be detected, e.g., if a predetermined number of consecutive TPC commands in the upward direction is obtained for increasing transmit power. The upward transmit power spike may be mitigated by limiting the transmit power, reducing the rate of transmit power adjustment in the upward direction, delaying and/or filtering TPC decisions used for transmit power adjustment, preventing upward adjustment of transmit power, and so on. Multiple states may be defined and used to facilitate power control with spike mitigation.Type: ApplicationFiled: May 7, 2004Publication date: November 10, 2005Inventors: Nitin Kasturi, Parvathanathan Subrahmanya
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Publication number: 20050239409Abstract: Techniques for controlling transmit power for a data transmission sent on multiple data channels, which may be intermittently active, are described. Each data channel is monitored for activity (e.g., based on an error correction code, received signaling information, received block energy, and so on) and deemed to be dormant or not dormant (e.g., based on the amount of elapsed time since activity was last detected on the data channel). A signal quality (SIR) target may be maintained for each non-dormant data channel and updated based on the status of received data blocks for the data channel. A final SIR target, used for power control of the data transmission, may be set to the highest SIR target among the SIR targets for the non-dormant data channels. The final SIR target may also be updated directly based on the status of received data blocks for the non-dormant data channels.Type: ApplicationFiled: April 15, 2004Publication date: October 27, 2005Inventors: Hyukjun Oh, Parvathanathan Subrahmanya, Nitin Kasturi
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Publication number: 20050143116Abstract: Techniques are provided to control the transmit power for data transmission on multiple transport channels having different signal quality (SIR) targets. A single SIR target is maintained for all transport channels, and this SIR target is adjusted based only on active transport channels. For each update interval, a data processor processes at least one data block received in the current update interval on at least one of the transport channels and provides the status of each received data block. A controller increases the SIR target based on an up step if any received data block is erased and decreases the SIR target based on a down step if all received data blocks are good. If any received data block is erased, the down step used to adjust the SIR target may be set to the smallest down step size required by all transport channels with erased data blocks.Type: ApplicationFiled: December 30, 2003Publication date: June 30, 2005Inventors: Chih-Ping Hsu, Parvathanathan Subrahmanya, Da-shan Shiu, Hyukjun Oh, Christopher Riddle, Nitin Kasturi
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Publication number: 20050113127Abstract: Various embodiments are provided for determining a set of acceptable transport format combinations for transmission on a current time frame. A set of acceptable modified rate power adjustment values is determined based on a maximum power level, an accumulated power commands and an initial power control command. A set of acceptable channel gain factors is determined based on the set of acceptable modified rate power adjustments values, and the set of acceptable transport format combinations is determined based on the set of acceptable channel gain factors. A possible set of modified rate power adjustment values is associated to a set of channel gain factors for determining the set of acceptable channel gain factors based on various design of a transmitter chain used for transmission of data from the mobile station.Type: ApplicationFiled: December 10, 2004Publication date: May 26, 2005Inventors: Yi Zhang, Nitin Kasturi, Alkinoos Vayanos, Subramanya Rao
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Patent number: 6882857Abstract: Various embodiments are provided for determining a set of acceptable transport format combinations for transmission on a current time frame. A set of acceptable modified rate power adjustment values is determined based on a maximum power level, an accumulated power commands and an initial power control command. A set of acceptable channel gain factors is determined based on the set of acceptable modified rate power adjustments values, and the set of acceptable transport format combinations is determined based on the set of acceptable channel gain factors. A possible set of modified rate power adjustment values is associated to a set of channel gain factors for determining the set of acceptable channel gain factors based on various design of a transmitter chain used for transmission of data from the mobile station.Type: GrantFiled: November 26, 2002Date of Patent: April 19, 2005Assignee: Qualcomm, IncorporatedInventors: Yi Zhang, Nitin Kasturi, Alkinoos Hector Vayanos, Subramanya P. N. Rao
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Publication number: 20040184569Abstract: The invention is directed toward a digital VGA that is implemented in the logarithmic domain. The digital VGA exploits logarithmic properties to replace a complex multiplier of a conventional digital VGA with a simple and inexpensive adder. Moreover, additional techniques are described to significantly reduce the size of one or more lookup tables (LUTs) implemented within the digital VGA. In this manner, the invention can realize a simple, low cost digital VGA.Type: ApplicationFiled: January 30, 2004Publication date: September 23, 2004Inventors: Raghu Challa, Nitin Kasturi, Nikolai Schlegel