Patents by Inventor Christine Fragouli
Christine Fragouli 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: 9264122Abstract: The burden of designing multiple training sequences for systems having multiple transmit antennas, is drastically reduced by employing a single sequence from which the necessary multiple sequences are developed. The single sequence is selected to create sequences that have an impulse-like autocorrelation function and zero cross correlations. A sequence of any desired length Nt can be realized for an arbitrary number of channel taps, L. The created sequences can be restricted to a standard constellation (that is used in transmitting information symbols) so that a common constellation mapper is used for both the information signals and the training sequence. In some applications a training sequence may be selected so that it is encoded with the same encoder that is used for encoding information symbols. Both block and trellis coding is possible in embodiments that employ this approach.Type: GrantFiled: December 18, 2014Date of Patent: February 16, 2016Assignee: AT&T Intellectual Property II, L.P.Inventors: Naofal Al-Dhahir, Christine Fragouli, William Turin
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Patent number: 8942335Abstract: The burden of designing multiple training sequences for systems having multiple transmit antennas, is drastically reduced by employing a single sequence from which the necessary multiple sequences are developed. The single sequence is selected to create sequences that have an impulse-like autocorrelation function and zero cross correlations. A sequence of any desired length Nt can be realized for an arbitrary number of channel taps, L. The created sequences can be restricted to a standard constellation (that is used in transmitting information symbols) so that a common constellation mapper is used for both the information signals and the training sequence. In some applications a training sequence may be selected so that it is encoded with the same encoder that is used for encoding information symbols. Both block and trellis coding is possible in embodiments that employ this approach.Type: GrantFiled: May 11, 2010Date of Patent: January 27, 2015Assignee: AT&T Intellectual Property II, L.P.Inventors: Naofal Al-Dhahir, Christine Fragouli, William Turin
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Patent number: 7826559Abstract: A training sequence is created for space-time diversity arrangement, having any training sequence length, while limiting the training sequence to a standard constellation. Given a number of channel unknowns that need to be estimated, L, a training sequence can be creates that yields minimum means squared estimation error for lengths Nt=kNPRUS+L?1, for any positive integer k?1, where NPRUS is a selected perfect roots-of-unity sequence (PRUS) of length N. The training sequence is created by concatenating k of the length N perfect roots-of-unity sequences, followed by L?1 initial symbols of that same PRUS. Good training sequences can be created for lengths Nt that cannot be obtained through the above method by concatenating a requisite number of symbols found through an exhaustive search.Type: GrantFiled: December 15, 2009Date of Patent: November 2, 2010Inventors: Naofal Al-Dhahir, Christine Fragouli, William Turin
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Publication number: 20100220803Abstract: The burden of designing multiple training sequences for systems having multiple transmit antennas, is drastically reduced by employing a single sequence from which the necessary multiple sequences are developed. The single sequence is selected to create sequences that have an impulse-like autocorrelation function and zero cross correlations. A sequence of any desired length Nt can be realized for an arbitrary number of channel taps, L. The created sequences can be restricted to a standard constellation (that is used in transmitting information symbols) so that a common constellation mapper is used for both the information signals and the training sequence. In some applications a training sequence may be selected so that it is encoded with the same encoder that is used for encoding information symbols. Both block and trellis coding is possible in embodiments that employ this approach.Type: ApplicationFiled: May 11, 2010Publication date: September 2, 2010Inventors: Naofal Al-Dhahir, Christine Fragouli, William Turin
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Patent number: 7746945Abstract: The burden of designing multiple training sequences for systems having multiple transmit antennas, is drastically reduced by employing a single sequence from which the necessary multiple sequences are developed. The single sequence is selected to create sequences that have an impulse-like autocorrelation function and zero cross correlations. A sequence of any desired length Nt can be realized for an arbitrary number of channel taps, L. The created sequences can be restricted to a standard constellation (that is used in transmitting information symbols) so that a common constellation mapper is used for both the information signals and the training sequence. In some applications a a training sequence may be selected so that it is encoded with the same encoder that is used for encoding information symbols. Both block and trellis coding is possible in embodiments that employ this approach.Type: GrantFiled: July 27, 2005Date of Patent: June 29, 2010Inventors: Naofal Al-Dhahir, Christine Fragouli, William Turin
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Publication number: 20100091890Abstract: A training sequence is created for space-time diversity arrangement, having any training sequence length, while limiting the training sequence to a standard constellation. Given a number of channel unknowns that need to be estimated, L, a training sequence can be creates that yields minimum means squared estimation error for lengths Nt=kNPRUS+L?1, for any positive integer k?1, where NPRUS is a selected perfect roots-of-unity sequence (PRUS) of length N. The training sequence is created by concatenating k of the length N perfect roots-of-unity sequences, followed by L?1 initial symbols of that same PRUS. Good training sequences can be created for lengths Nt that cannot be obtained through the above method by concatenating a requisite number of symbols found through an exhaustive search.Type: ApplicationFiled: December 15, 2009Publication date: April 15, 2010Inventors: Naofal Al-Dhahir, Christine Fragouli, William Turin
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Patent number: 7668255Abstract: A training sequence is created for space-time diversity arrangement, having any training sequence length, while limiting the training sequence to a standard constellation. Given a number of channel unknowns that need to be estimated, L, a training sequence can be creates that yields minimum means squared estimation error for lengths Nt=kNPRUS+L?1, for any positive integer k?1, where NPRUS a selected perfect roots-of-unity sequence (PRUS) of length N. The training sequence is created by concatenating k of the length N perfect roots-of-unity sequences, followed by L?1 initial symbols of that same PRUS. Good training sequences can be created for lengths Nt that cannot be obtained through the above method by concatenating a requisite number of symbols found through an exhaustive search.Type: GrantFiled: July 18, 2006Date of Patent: February 23, 2010Inventors: Naofal Al-Dhahir, Christine Fragouli, William Turin
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Patent number: 7154964Abstract: A training sequence is created for space-time diversity arrangement, having any training sequence length, while limiting the training sequence to a standard constellation. Given a number of channel unknowns that need to be estimated, L, a training sequence can be creates that yields minimum means squared estimation error for lengths Nt=kNPRUS+L?1, for any positive integer k?1, where NPRUS is a selected perfect roots-of-unity sequence (PRUS) of length N. The training sequence is created by concatenating k of the length N perfect roots-of-unity sequences, followed by L?1 initial symbols of that same PRUS. Good training sequences can be created for lengths Nt that cannot be obtained through the above method by concatenating a requisite number of symbols found through an exhaustive search.Type: GrantFiled: September 20, 2001Date of Patent: December 26, 2006Assignee: AT&T Corp.Inventors: Naofal Al-Dhahir, Christine Fragouli, William Turin
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Publication number: 20050265478Abstract: The burden of designing multiple training sequences for systems having multiple transmit antennas, is drastically reduced by employing a single sequence from which the necessary multiple sequences are developed. The single sequence is selected to create sequences that have an impulse-like autocorrelation function and zero cross correlations. A sequence of any desired length Nt can be realized for an arbitrary number of channel taps, L. The created sequences can be restricted to a standard constellation (that is used in transmitting information symbols) so that a common constellation mapper is used for both the information signals and the training sequence. In some applications a a training sequence may be selected so that it is encoded with the same encoder that is used for encoding information symbols. Both block and trellis coding is possible in embodiments that employ this approach.Type: ApplicationFiled: July 27, 2005Publication date: December 1, 2005Inventors: Naofal Al-Dhahir, Christine Fragouli, William Turin
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Patent number: 6959047Abstract: The burden of designing multiple training sequences for systems having multiple transmit antennas, is drastically reduced by employing a single sequence from which the necessary multiple sequences are developed. The single sequence is selected to create sequences that have an impulse-like autocorrelation function and zero cross correlations. A sequence of any desired length Nt can be realized for an arbitrary number of channel taps, L. The created sequences can be restricted to a standard constellation (that is used in transmitting information symbols) so that a common constellation mapper is used for both the information signals and the training sequence. In some applications a a training sequence may be selected so that it is encoded with the same encoder that is used for encoding information symbols. Both block and trellis coding is possible in embodiments that employ this approach.Type: GrantFiled: September 20, 2001Date of Patent: October 25, 2005Assignee: AT&T CorpInventors: Naofal Al-Dhahir, Christine Fragouli, William Turin
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Patent number: RE44827Abstract: The burden of designing multiple training sequences for systems having multiple transmit antennas, is drastically reduced by employing a single sequence from which the necessary multiple sequences are developed. The single sequence is selected to create sequences that have an impulse-like autocorrelation function and zero cross correlations. A sequence of any desired length Nt can be realized for an arbitrary number of channel taps, L. The created sequences can be restricted to a standard constellation (that is used in transmitting information symbols) so that a common constellation mapper is used for both the information signals and the training sequence. In some applications a a training sequence may be selected so that it is encoded with the same encoder that is used for encoding information symbols. Both block and trellis coding is possible in embodiments that employ this approach.Type: GrantFiled: March 18, 2013Date of Patent: April 8, 2014Assignee: AT&T Intellectual Property II, L.P.Inventors: Naofal Al-Dhahir, Christine Fragouli, William Turin