Patents by Inventor Ananthanarayanan Chockalingam
Ananthanarayanan Chockalingam 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: 8964889Abstract: A device and method for precoding vectors in a communication system is provided. A transmitter may precode a data vector using information regarding a communication channel prior to transmitting the data vector. The transmitter may precode the data vector in a manner that reduces an energy value of a resulting transmit data vector so as to minimize interference in a received signal at a receiver. The transmitter may perturb entries of the data vector one-by-one in an iterative fashion until a minimum in an energy value of the transmit data vector is obtained.Type: GrantFiled: October 23, 2012Date of Patent: February 24, 2015Assignee: Indian Institute of ScienceInventors: Ananthanarayanan Chockalingam, Balaji Sundar Rajan, Saif Khan Mohammed
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Patent number: 8804858Abstract: Techniques for enabling an estimate of a transmittal signal vector, given a received signal vector and a channel matrix to be computed, are provided. An initial solution signal vector for the estimate is calculated, and based on the initial estimate, a pool of possible solutions is generated. Methods described herein may be iterative in nature, and may cycle through possible estimates of the transmitted signal vector so as to continually improve the estimates and the pool of possible estimates. The methods may terminate once stopping criteria are reached. In some example methods, solutions may be marked at taboo and a taboo period can be established that indicates a number of subsequent iterations for which the current solution signal vector cannot be considered.Type: GrantFiled: July 2, 2013Date of Patent: August 12, 2014Assignee: Indian Institute of ScienceInventors: Ananthanarayanan Chockalingam, Balaji Sundar Rajan, Srinidhi Nagaraja, Saif Khan Mohammed
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Publication number: 20140133591Abstract: A method of determining a transmitted vector (x) in a MIMO receiver includes the steps of receiving a received vector (y) representative of the transmitted vector (x), generating a first random number and forming, in a first iteration, a first symbol of a first candidate vector, the candidate vector representing a potential solution vector. The step of forming is based on a first approach if the first random number is greater than a first predetermined value (q), but is based on a second approach if the random number is less than or equal to the first predetermined value (q). The first approach randomly selects the first symbol from a uniform distribution of symbols in the transmission alphabet. The second approach selects the first symbol based on Gibbs sampling. The method represents a randomized Markov Chain Monte Carlo (RMCMC) sampling technique.Type: ApplicationFiled: January 21, 2014Publication date: May 15, 2014Applicant: INDIAN INSTITUTE OF SCIENCEInventors: Ananthanarayanan Chockalingam, Balaji Sundar Rajan, Tanumay Datta, Ashok Kumar. N
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Patent number: 8675780Abstract: A method of determining a transmitted vector (x) in a MIMO receiver includes the steps of receiving a received vector (y) representative of the transmitted vector (x), generating a first random number and forming, in a first iteration, a first symbol of a first candidate vector, the candidate vector representing a potential solution vector. The step of forming is based on a first approach if the first random number is greater than a first predetermined value (q), but is based on a second approach if the random number is less than or equal to the first predetermined value (q). The first approach randomly selects the first symbol from a uniform distribution of symbols in the transmission alphabet. The second approach selects the first symbol based on Gibbs sampling. The method represents a randomized Markov Chain Monte Carlo (RMCMC) sampling technique.Type: GrantFiled: May 16, 2012Date of Patent: March 18, 2014Assignee: Indian Institute of ScienceInventors: Ananthanarayanan Chockalingam, Balaji Sundar Rajan, Tanumay Datta, Ashok Kumar. N
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Patent number: 8634490Abstract: A receiver of a multiple-input multiple-output (MIMO) system performs QR decomposition of the channel matrix to enable detection of a transmitted vector in a layered manner. In each layer, a sub-vector of the transmitted vector is estimated. A reactive tabu search is performed if an estimated symbol differs from a nearest symbol in the alphabet by a predetermined value. The receiver may order the entries of the channel matrix prior to QR decomposition to enable estimation in an optimum order. In another embodiment, a receiver performs multiple reactive tabu searches to estimate a transmitted vector. The receiver employs a fixed threshold or a variable threshold for a cost function used in the multiple reactive tabu searches depending on whether the MIMO system is under-determined or not. The techniques enable low bit-error rate (BER) performance in MIMO systems with large number of antennas and when higher-order modulation techniques are used.Type: GrantFiled: July 10, 2012Date of Patent: January 21, 2014Assignee: Indian Institute of ScienceInventors: Ananthanarayanan Chockalingam, Balaji Sundar Rajan, Srinidhi Nagaraja, Tanumay Datta
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Patent number: 8605808Abstract: Disclosed is a method and system to detect data transmitted by multiple transmit antennas. The method comprises selecting a starting data block that is either a random data block or an output data block from known detectors. Also, the method comprises changing each symbol of the starting data block one symbol at a time to identify a data block which has minimum euclidean distance from the starting data block as detected data block. Next, changing two symbols of the detected data block at a time to identify a data block which has minimum euclidean distance from the starting data block as second data block and assigning the second data block as the starting data block. Repeating the above steps, if the minimum euclidean distance of second data block is better than that of the detected data block, and determining the detected data block as the data transmitted.Type: GrantFiled: February 25, 2009Date of Patent: December 10, 2013Assignee: Indian Institute of ScienceInventors: Ananthanarayanan Chockalingam, Balaji Sundar Rajan, Saif Khan Mohammed
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Publication number: 20130315356Abstract: Techniques for enabling an estimate of a transmittal signal vector, given a received signal vector and a channel matrix to be computed, are provided. An initial solution signal vector for the estimate is calculated, and based on the initial estimate, a pool of possible solutions is generated. Methods described herein may be iterative in nature, and may cycle through possible estimates of the transmitted signal vector so as to continually improve the estimates and the pool of possible estimates. The methods may terminate once stopping criteria are reached. In some example methods, solutions may be marked at taboo and a taboo period can be established that indicates a number of subsequent iterations for which the current solution signal vector cannot be considered.Type: ApplicationFiled: July 2, 2013Publication date: November 28, 2013Applicant: Indian Institute of ScienceInventors: Ananthanarayanan CHOCKALINGAM, Balaji Sundar RAJAN, Srinidhi NAGARAJA, Saif Khan MOHAMMED
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Patent number: 8503544Abstract: Techniques for enabling an estimate of a transmitted signal vector, given a received signal vector and a channel matrix to be computed, are provided. An initial solution signal vector for the estimate is calculated, and based on the initial estimate, a pool of possible solutions is generated. Methods described herein may be iterative in nature, and may cycle through possible estimates of the transmitted signal vector so as to continually improve the estimates and the pool of possible estimates. The methods may terminate once stopping criteria are reached. In some example methods, solutions may be marked at taboo and a taboo period can be established that indicates a number of subsequent iterations for which the current solution signal vector cannot be considered.Type: GrantFiled: April 30, 2010Date of Patent: August 6, 2013Assignee: Indian Institute of ScienceInventors: Ananthanarayanan Chockalingam, Balaji Sundar Rajan, Srinidhi Nagaraja, Saif Khan Mohammed
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Publication number: 20130039436Abstract: A receiver of a multiple-input multiple-output (MIMO) system performs QR decomposition of the channel matrix to enable detection of a transmitted vector in a layered manner. In each layer, a sub-vector of the transmitted vector is estimated. A reactive tabu search is performed if an estimated symbol differs from a nearest symbol in the alphabet by a predetermined value. The receiver may order the entries of the channel matrix prior to QR decomposition to enable estimation in an optimum order. In another embodiment, a receiver performs multiple reactive tabu searches to estimate a transmitted vector. The receiver employs a fixed threshold or a variable threshold for a cost function used in the multiple reactive tabu searches depending on whether the MIMO system is under-determined or not. The techniques enable low bit-error rate (BER) performance in MIMO systems with large number of antennas and when higher-order modulation techniques are used.Type: ApplicationFiled: July 10, 2012Publication date: February 14, 2013Applicant: INDIAN INSTITUTE OF SCIENCEInventors: Ananthanarayanan Chockalingam, Balaji Sundar Rajan, Srinidhi Nagaraja, Tanumay Datta
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Publication number: 20120307924Abstract: A method of determining a transmitted vector (x) in a MIMO receiver includes the steps of receiving a received vector (y) representative of the transmitted vector (x), generating a first random number and forming, in a first iteration, a first symbol of a first candidate vector, the candidate vector representing a potential solution vector. The step of forming is based on a first approach if the first random number is greater than a first predetermined value (q), but is based on a second approach if the random number is less than or equal to the first predetermined value (q). The first approach randomly selects the first symbol from a uniform distribution of symbols in the transmission alphabet. The second approach selects the first symbol based on Gibbs sampling. The method represents a randomized Markov Chain Monte Carlo (RMCMC) sampling technique.Type: ApplicationFiled: May 16, 2012Publication date: December 6, 2012Applicant: INDIAN INSTITUTE OF SCIENCEInventors: Ananthanarayanan Chockalingam, Balaji Sundar Rajan, Tanumay Datta, Ashok Kumar. N
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Patent number: 8320432Abstract: A device and method for precoding vectors in a communication system is provided. A transmitter may precode a data vector using information regarding a communication channel prior to transmitting the data vector. The transmitter may precode the data vector in a manner that reduces an energy value of a resulting transmit data vector so as to minimize interference in a received signal at a receiver. The transmitter may perturb entries of the data vector one-by-one in an iterative fashion until a minimum in an energy value of the transmit data vector is obtained.Type: GrantFiled: April 27, 2009Date of Patent: November 27, 2012Assignee: Indian Institute of Science at BangaloreInventors: Ananthanarayanan Chockalingam, Balaji Sundar Rajan, Saif Khan Mohammed
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Patent number: 8116411Abstract: A method to detect data transmitted from multiple antennas, said method comprising steps of: selecting a starting data block and calling it as previous data block; defining a set of indices of bits to be checked for possible flip in the previous data block as a check candidate set; applying update rule to obtain updated data block using the previous data block and the check candidate set, wherein the update is made in such a manner that change in likelihood is positive; checking if the updated data block and several consecutive previous data blocks are the same; if yes, declare the updated data block as the detected data block; if no, make updated data block as previous data block and repeat updation of data block.Type: GrantFiled: August 22, 2007Date of Patent: February 14, 2012Assignee: Indian Institute of ScienceInventors: Ananthanarayanan Chockalingam, Balaji Sundar Rajan, Kalepalli Vishnu Vardhan, Saif Khan Mohammed
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Publication number: 20110268203Abstract: Techniques for enabling an estimate of a transmitted signal vector, given a received signal vector and a channel matrix to be computed, are provided. An initial solution signal vector for the estimate is calculated, and based on the initial estimate, a pool of possible solutions is generated. Methods described herein may be iterative in nature, and may cycle through possible estimates of the transmitted signal vector so as to continually improve the estimates and the pool of possible estimates. The methods may terminate once stopping criteria are reached. In some example methods, solutions may be marked at taboo and a taboo period can be established that indicates a number of subsequent iterations for which the current solution signal vector cannot be considered.Type: ApplicationFiled: April 30, 2010Publication date: November 3, 2011Applicant: INDIAN INSTITUTE OF SCIENCEInventors: Ananthanarayanan Chockalingam, Balaji Sundar Rajan, Srinidhi N., Saif Khan Mohammed
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Publication number: 20110069746Abstract: The present invention relates to a system and a multistage signal detection method to jointly detect the data symbols transmitted from multiple transmit antennas in a communication terminal and received using multiple receive antennas in another communication terminal.Type: ApplicationFiled: February 25, 2009Publication date: March 24, 2011Applicant: INDIAN INSTITUTE OF SCIENCEInventors: Ananthanarayanan Chockalingam, Balaji Sundar Rajan, Saif Khan Mohammed
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Publication number: 20090041145Abstract: A method to detect data transmitted from multiple antennas, said method comprising steps of: selecting a starting data block and calling it as previous data block; defining a set of indices of bits to be checked for possible flip in the previous data block as a check candidate set; applying update rule to obtain updated data block using the previous data block and the check candidate set, wherein the update is made in such a manner that change in likelihood is positive; checking if the updated data block and several consecutive previous data blocks are the same; if yes, declare the updated data block as the detected data block; if no, make updated data block as previous data block and repeat updation of data block. FIG.Type: ApplicationFiled: August 22, 2007Publication date: February 12, 2009Inventors: Ananthanarayanan Chockalingam, Balaji Sundar Rajan, Kalepalli Vishnu Vardhan, Saif Khan Mohammed
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Patent number: 7301915Abstract: A method for reducing the number of required frequency and time hypotheses to acquire an access transmission in a satellite communication system. By reducing the number of required hypotheses, the amount of hardware required to acquire the access transmission is reduced. The method of the present invention reduces the number of required hypotheses by reducing the range of possible frequency and timing values of the access transmission. The range of possible frequency and timing values is reduced by determining the frequency and time uncertainties over individual satellite beams rather than over an entire satellite footprint.Type: GrantFiled: February 11, 2002Date of Patent: November 27, 2007Assignee: QUALCOMM IncorporatedInventors: Ananthanarayanan Chockalingam, Nathan E. Tenny, David S. Miller
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Patent number: 6714780Abstract: A method for reducing call dropping rates in a multi-beam communication system. The multi-beam communication system includes a user terminal, a gateway, and a plurality of beam sources, where each beam source projects a plurality of beams, and where a communication link between the user terminal and the gateway is established on one or more beams. The method according to the present invention relies on a messaging protocol between the gateway and the user terminal. Based on messages sent from the user terminal to the gateway, preferably on a preselected periodic basis, the gateway can determine the more desirable beam(s) for transmitting data or information to the user terminal. The messages sent from the user terminal to the gateway contain values representing beam strengths as measured at the user terminal. The gateway uses the user terminal measured beam strengths to select the beams that should be used for transmitting data or information to the user terminal.Type: GrantFiled: June 12, 2001Date of Patent: March 30, 2004Assignee: Qualcomm IncorporatedInventors: Franklin P. Antonio, Gene W. Marsh, Richard A. Stewart, Marie M. Bjerede, Ananthanarayanan Chockalingam, Arthur S. Kerns, Brian Butler, Matthew S. Grob, James T. Determan, Douglas Grover, Leonard N. Schiff, William G. Ames
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Publication number: 20020154608Abstract: A method for reducing the number of required frequency and time hypotheses to acquire an access transmission in a satellite communication system. By reducing the number of required hypotheses, the amount of hardware required to acquire the access transmission is reduced. The method of the present invention reduces the number of required hypotheses by reducing the range of possible frequency and timing values of the access transmission. The range of possible frequency and timing values is reduced by determining the frequency and time uncertainties over individual satellite beams rather than over an entire satellite footprint.Type: ApplicationFiled: February 11, 2002Publication date: October 24, 2002Applicant: Qualcomm, Inc.Inventors: Ananthanarayanan Chockalingam, Nathan E. Tenny, David S. Miller
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Patent number: 6381225Abstract: A method for reducing the number of required frequency and time hypotheses to acquire an access transmission in a satellite communication system. By reducing the number of required hypotheses, the amount of hardware required to acquire the access transmission is reduced. The method of the present invention reduces the number of required hypotheses by reducing the range of possible frequency and timing values of the access transmission. The range of possible frequency and timing values is reduced by determining the frequency and time uncertainties over individual satellite beams rather than over an entire satellite footprint.Type: GrantFiled: August 27, 1998Date of Patent: April 30, 2002Assignee: Qualcomm IncorporatedInventors: Ananthanarayanan Chockalingam, Nathan E. Tenny, David S. Miller
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Patent number: 6208858Abstract: A method for reducing call dropping rates in a multi-beam communication system. The multi-beam communication system includes a user terminal, a gateway, and a plurality of beam sources, where each beam source projects a plurality of beams, and where a communication link between the user terminal and the gateway is established on one or more beams. The method according to the present invention relies on a messaging protocol between the gateway and the user terminal. Based on messages sent from the user terminal to the gateway, preferably on a preselected periodic basis, the gateway can determine the more desirable beam(s) for transmitting data or information to the user terminal. The messages sent from the user terminal to the gateway contain values representing beam strengths as measured at the user terminal. The gateway uses the user terminal measured beam strengths to select the beams that should be used for transmitting data or information to the user terminal.Type: GrantFiled: July 21, 1998Date of Patent: March 27, 2001Assignee: Qualcomm IncorporatedInventors: Franklin P. Antonio, Gene W. Marsh, Richard A. Stewart, Marie M. Bjerede, Ananthanarayanan Chockalingam, Arthur S. Kerns, Brian Butler, Matthew S. Grob, James T. Determan, Douglas Grover, Leonard N. Schiff, William G. Ames