Patents by Inventor Constantinos B Papadias
Constantinos B Papadias 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: 7760685Abstract: In a method of improving system throughput while reducing packet delay for users of a wireless communication system, a user may be selected from a user population based on a parameter that is tracked for each user of the user population. A preferred beam for the user may be determined based on a highest running average data rate from each beam of a finite plurality of selectable beams so as to maximize the selected user's chances to be scheduled to receive the next packet. The preferred beam may be used for transmitting a pilot signal for scheduling a user in the user population to receive a next transmission on the preferred beam.Type: GrantFiled: February 9, 2007Date of Patent: July 20, 2010Assignee: Alcatel-Lucent USA Inc.Inventors: Dan Avidor, Jonathan Ling, Constantinos B. Papadias
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Patent number: 7391830Abstract: A receiver of digital data bursts is provided comprising an antenna array, a first space time filter having filter coefficients initialized by estimation over just training data in a received burst and providing symbol estimates and a second space time filter having filter coefficients initialized by estimation over the received burst and providing symbol estimates. In use at least one pass to determine a symbol estimate in the received burst is undertaken by each space time filter and a selector operates to determine which of the first and second filters provides the symbol estimate closer to an expected value.Type: GrantFiled: September 24, 2003Date of Patent: June 24, 2008Assignee: Lucent Technologies Inc.Inventors: Alexandr Kuzminskiy, Constantinos B Papadias
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Patent number: 7239879Abstract: In a method of determining a beam to be generated for a user, a user may be selected from a user population based on a parameter that is tracked for each user in the user population, and a beam preferred by the selected user may be determined. The preferred beam may be generated and used by a base station to transmit a pilot signal to the user population. Each user of the user population responds to the pilot signal. The base station may run a scheduling algorithm and schedule a user based on feedback received from all the users in the user population, and information may be transmitted to the scheduled user using the preferred beam.Type: GrantFiled: November 26, 2003Date of Patent: July 3, 2007Assignee: Lucent Technologies Inc.Inventors: Dan Avidor, Jonathan Ling, Constantinos B. Papadias
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Patent number: 7184488Abstract: A method and apparatus for reducing the bit rate of multi-input systems that employ space-time coding by displacing in signal space the derivatives of a symbol. A mapped particular symbol is space-time coded to generate transmit-sequences having a phase-shifted version of the particular symbol, the phase-shifted version and the particular symbol differing in phase by an amount other than by 90°, 180°, and 270°. In one embodiment, the particular symbol represents a point in a first symbol constellation and the derivatives of the particular symbol represent points in a displaced symbol constellation. In another embodiment, the particular symbol and another symbol are space-time coded to form the transmit-sequences. The derivatives of the particular symbol represent points in a first symbol constellation and derivatives of the other symbol represent points of a second symbol constellation. The two constellations are displaced versions of each other.Type: GrantFiled: March 15, 2002Date of Patent: February 27, 2007Assignee: Lucent Technologies Inc.Inventors: Constantinos B Papadias, Naresh Sharma
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Patent number: 7116722Abstract: A method and apparatus for increasing the capacity of a multiple-input and/or multiple-output system. Each sub-stream of a primary data stream is stratified to produce a processed sub-stream whose strata can be separated out and decoded with an acceptable error rate. A sub-stream can be stratified by dividing it into a plurality of sub-stream-components that are processed to obtain strata, with each stratum representing one of the sub-stream-components. The strata are then combined to obtain the processed sub-stream. Stratifying allows a particular processed sub-stream's strata have different transmit features from each other, such as different bit rates, or different power levels, or both. This reduces the interference for some of the strata of each processed sub-stream since as stratum are separated out and decoded they are no longer interference for the other strata. Thus, allowing for a higher overall bit rate for the processed sub-streams.Type: GrantFiled: July 10, 2001Date of Patent: October 3, 2006Assignee: Lucent Technologies Inc.Inventors: Gerard J. Foschini, Constantinos B. Papadias
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Patent number: 7050510Abstract: When using four transmit antennas, conventional channel coding is employed for a decoupled space-time coding approach for each of a number, L, of data substreams derived from the overall source bit stream. The symbols of the data substreams, after any encoding, are processed and the resulting derivatives of the encoded data substreams, which includes at least the complex conjugate of one of the encoded symbols, are grouped to form four transmit time sequences each one spanning L symbol periods which form a transmission matrix B. Each row of the matrix corresponds to an antenna, and the elements of each row represent the samples of a temporal sequence that is emitted by the antenna in L symbol periods.Type: GrantFiled: December 29, 2000Date of Patent: May 23, 2006Assignee: Lucent Technologies Inc.Inventors: Gerard J Foschini, Constantinos B. Papadias
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Patent number: 6907252Abstract: A method and apparatus for detecting the presence of mobile terminals such as cell phones that are in the vicinity of one or more selected locations. The detected devices are identified and such information may then be provided to an application for its use. Specifically, a detector is installed at a selected location or locations for monitoring the transmissions of mobile terminals that come nearby. When such a transmission is detected, information from the base station with which the mobile terminal is communicating provides identification data, and based on timing relationships between the detected transmission and the data received from the base station, the detected mobile terminal may be specifically identified.Type: GrantFiled: July 3, 2002Date of Patent: June 14, 2005Assignee: Lucent Technologies Inc.Inventors: Constantinos B Papadias, Manolis Tsangaris, Giovanni Vannucci
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Publication number: 20040062328Abstract: A receiver of digital data bursts is provided comprising an antenna array, a first space time filter having filter coefficients initialised by estimation over just training data in a received burst and providing symbol estimates and a second space time filter having filter coefficients initialised by estimation over the received burst and providing symbol estimates. In use at least one pass to determine a symbol estimate in the received burst is undertaken by each space time filter and a selector operates to determine which of the first and second filters provides the symbol estimate closer to an expected value.Type: ApplicationFiled: September 24, 2003Publication date: April 1, 2004Inventors: Alexandr Kuzminskiy, Constantinos B. Papadias
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Patent number: 6654719Abstract: The present invention provides a method for blind separation of independent source signals. The preceding is accomplished by disclosing new techniques for dealing with the problem of blind separation of independent source signals. The method of the present invention consists of identifying a simple constrained criterion which stems directly from derived conditions for source separation. Using this criterion, observed and output signals are used to control a filtering matrix. After being initialized, the filtering matrix is updated and projected to the closest unitary matrix. Until the filtering matrix has converged, it continues to be updated and projected to the closest unitary matrix. Once convergence has occurred, the source signals have been recovered.Type: GrantFiled: March 14, 2000Date of Patent: November 25, 2003Assignee: Lucent Technologies Inc.Inventor: Constantinos B. Papadias
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Publication number: 20030174782Abstract: A method and apparatus for reducing the bit rate of multi-input systems that employ space-time coding by displacing in signal space the derivatives of a symbol. A mapped particular symbol is space-time coded to generate transmit-sequences having a phase-shifted version of the particular symbol, the phase-shifted version and the particular symbol differing in phase by an amount other than by 90°, 180°, and 270°. In one embodiment, the particular symbol represents a point in a first symbol constellation and the derivatives of the particular symbol represent points in a displaced symbol constellation. In another embodiment, the particular symbol and another symbol are space-time coded to form the transmit-sequences. The derivatives of the particular symbol represent points in a first symbol constellation and derivatives of the other symbol represent points of a second symbol constellation. The two constellations are displaced versions of each other.Type: ApplicationFiled: March 15, 2002Publication date: September 18, 2003Inventors: Constantinos B. Papadias, Naresh Sharma
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Publication number: 20030013460Abstract: A method and apparatus for detecting the presence of mobile terminals such as cell phones that are in the vicinity of one or more selected locations. The detected devices are identified and such information may then be provided to an application for its use. Specifically, a detector is installed at a selected location or locations for monitoring the transmissions of mobile terminals that come nearby. When such a transmission is detected, information from the base station with which the mobile terminal is communicating provides identification data, and based on timing relationships between the detected transmission and the data received from the base station, the detected mobile terminal may be specifically identified.Type: ApplicationFiled: July 3, 2002Publication date: January 16, 2003Inventors: Constantinos B. Papadias, Manolis Tsangaris, Giovanni Vannucci
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Publication number: 20020142723Abstract: A method and apparatus for increasing the capacity of a multiple-input and/or multiple-output system. Each sub-stream of a primary data stream is stratified to produce a processed sub-stream whose strata can be separated out and decoded with an acceptable error rate. A sub-stream can be stratified by dividing it into a plurality of sub-stream-components that are processed to obtain strata, with each stratum representing one of the sub-stream-components. The strata are then combined to obtain the processed sub-stream. Stratifying allows a particular processed sub-stream's strata have different transmit features from each other, such as different bit rates, or different power levels, or both. This reduces the interference for some of the strata of each processed sub-stream since as stratum are separated out and decoded they are no longer interference for the other strata. Thus, allowing for a higher overall bit rate for the processed sub-streams.Type: ApplicationFiled: July 10, 2001Publication date: October 3, 2002Inventors: Gerard J. Foschini, Constantinos B. Papadias
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Publication number: 20020118770Abstract: When using four transmit antennas, conventional channel coding is employed for a decoupled space-time coding approach for each of a number, L, of data substreams derived from the overall source bit stream. The symbols of the data substreams, after any encoding, are processed and the resulting derivatives of the encoded data substreams, which includes at least the complex conjugate of one of the encoded symbols, are grouped to form four transmit time sequences each one spanning L symbol periods which form a transmission matrix B. Each row of the matrix corresponds to an antenna, and the elements of each row represent the samples of a temporal sequence that is emitted by the antenna in L symbol periods.Type: ApplicationFiled: December 29, 2000Publication date: August 29, 2002Inventors: Gerard J. Foschini, Constantinos B. Papadias