Crosstalk Suppression Patents (Class 370/201)
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Publication number: 20070274197Abstract: A method and apparatus for performing stream weighting in a spatial-division multiple access communication system is provided herein. During operation the base station receiver receives channel information from mobiles (also known as users or nodes) and calculates transmit antenna weights that that maximize the power delivered to each mobile while allowing for a small amount of crosstalk to exist between users. Information or data is transmitted to the nodes utilizing the appropriate stream weights. By allowing tolerable amounts of cross talk, the coherent gain to the desired SDMA user can be increased, and thus the overall performance is improved.Type: ApplicationFiled: May 23, 2006Publication date: November 29, 2007Applicant: MOTOROLA, INC.Inventors: Timothy A. Thomas, Frederick W. Vook
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Publication number: 20070268811Abstract: An arrangement for use in a telecommunication system includes a binder of subscriber lines, a local transceiver circuit, and a far-end crosstalk cancellation circuit. Each of the subscriber lines ends at one of a plurality of remote user terminals. The local transceiver circuit is associated with the binder of subscriber lines and comprises a plurality of substantially identical transceiver modules, each of the transceiver modules being associated to one or a small number of subscriber lines. The far-end crosstalk cancellation circuit is configured to reduce far-end crosstalk between the subscriber lines of the binder, and is operably connected to interface with at least parts of the received data of the respective local transceiver modules. The far-end crosstalk cancellation circuit operable to implement a blind training algorithm for at least one victim subscriber line based on signals received by the respective associated transceiver modules.Type: ApplicationFiled: May 18, 2006Publication date: November 22, 2007Applicant: Infineon Technologies AGInventor: Axel Clausen
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Patent number: 7289554Abstract: A method and apparatus for efficient filter structure for an enhanced operation of an ADSL-DMT modem on a subscriber loop with an environment consisting of ISDN interference. The method performs equalization of the channel by impulse response shortening and at the same time rejecting interference signals exhibiting cyclostationary properties. The method and apparatus for reducing the crosstalk involves a frequency-shifted versions of the received signal being filtered through frequency-shifted adaptive filters in the appropriate branches, and providing a joint time domain equalizer/crosstalk canceller to perform equalization of the channel and crosstalk cancellation in one instance and a separate crosstalk canceller to cancel crosstalk plus a time domain equalizer to equalize the channel.Type: GrantFiled: July 15, 2003Date of Patent: October 30, 2007Assignee: Brooktree Broadband Holding, Inc.Inventor: Laurent Francis Alloin
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Patent number: 7283460Abstract: Data are transmitted over a bus including a plurality of lines, wherein energy is dissipated as a result of data transmission. Preferably, the data to be transmitted in parallel are partitioned in a plurality of clusters of data bits. Each cluster is subject to re-ordering according to a set of reordering patterns to produce a corresponding set of respective candidate clusters of data bits. Crosstalk activity values related to transmitting the various candidate clusters are calculated and compared to identify an optimum cluster of data bits that minimizes the energy dissipated as a result of transmission by jointly minimizing the switching activity and the crosstalk activity. The optimum cluster of data bits so identified is then used for transmission over the bus. The optimum cluster of data bits thus causes those bits that give rise to high crosstalk activity to be allotted to bus lines having lower crosstalk capacitance values.Type: GrantFiled: April 3, 2006Date of Patent: October 16, 2007Assignee: STMicroelectronics S.r.l.Inventors: Giuseppe Visalli, Francesco Pappalardo
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Patent number: 7280463Abstract: The bandwidth of a first variable IF filter (5) for a neighbour channel suppression of a currently received channel, which first variable IF filter (5) is arranged in a first reception path of a broadcast receiver additionally comprising at least one second reception path is controlled by obtaining at least one first quality signal corresponding to a received broadcast signal on basis of a first filtering of the received and eventually pre-processed broadcast signal with said first variable IF filter (5) set to a predetermined bandwidth, obtaining at least one second quality signal corresponding to said received broadcast signal on basis of at least one second filtering of the received and eventually pre-processed broadcast signal with a second variable IF filter (13) arranged in said at least one second reception path with a bandwidth different to the first variable IF filter (5) bandwidth and/or with a different filter characteristic, and controlling the bandwidth of the first variable IF filter (5) on basiType: GrantFiled: December 4, 2002Date of Patent: October 9, 2007Assignee: Sony Deutschland GmbHInventors: Jens Wildnagen, Rolf Nöthlings
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Publication number: 20070217323Abstract: An apparatus and method for reducing inter-subcarrier interference (ICI) in an Orthogonal Frequency Division Multiple Access (OFDMA) system are provided. The method includes determining a correction frequency from uplink intermediate frequency (IF) signals subjected to analog-to-digital conversion when an uplink radio frequency (RF) signal is input through an antenna of a base station and each uplink IF signal (I(n)+j1(n)) is input,; and correcting the uplink IF signal so as to correspond to the determined correction frequency. Thereby, it is possible to reduce the ICI of each terminal caused by mismatching of the interval of the inter-subcarrier center frequency of each terminal that constitutes the uplink signal in the OFDMA system.Type: ApplicationFiled: November 20, 2006Publication date: September 20, 2007Applicant: SAMSUNG ELECTRONICS CO., LTD.Inventors: Seong-Yun Ko, Joo-Yong Park, Myeon-Kee Youn
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Publication number: 20070183301Abstract: A method and apparatus to reduce crosstalk in a communication system are described.Type: ApplicationFiled: February 5, 2006Publication date: August 9, 2007Inventors: Ali S. Sadri, Alexey V. Khoryaev, Viktor T. Ermolayev, Roman O. Maslennikov
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Patent number: 7251213Abstract: A method of measuring echo path delay in a circuit having echo cancellers after enabling an echo signal to pass through the echo cancellers. The known time for a given echo canceller to disable is subtracted from the overall test signal duration. This quantity can be subtracted from the overall echo duration to compute the echo path delay.Type: GrantFiled: September 17, 2002Date of Patent: July 31, 2007Assignee: AT&T Corp.Inventors: Bing Chen, Wallace F. Smith, Jr.
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Patent number: 7190665Abstract: Crosstalk can be cancelled in a composite communication signal (ym) which includes a primary signal component associated with communication data and which also includes a crosstalk signal component produced by applying a crosstalk coupling function to crosstalk data. An estimate (R, RCb(0), RCb(?f)AVG) of a statistical characteristic of the crosstalk signal component is obtained from the composite communication signal. A cancellation signal (26, 46) is generated based on the statistical characteristic estimate, and an estimate (29) of the communication data is produced based on the composite communication signal and the cancellation signal.Type: GrantFiled: April 19, 2002Date of Patent: March 13, 2007Assignee: Texas Instruments IncorporatedInventors: Nirmal Warke, Nadeem Ahmed
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Patent number: 7187711Abstract: In a communications system having a first modem pool for communicating with a second modem pool, each modem pool including a plurality of modems and having at least one NEXT cancellation filter, a method for modem wake-up including the steps of, during a first time period, a) activating at least one of the modems in the first modem pool, b) deactivating at least one of the modems in the second modem pool, for at least one target modem in the first modem pool c) activating the first modem pool NEXT canceller filter, d) measuring the NEXT transfer function for the target modem and at least one other disturber modem in the first modem pool, and, during a second time period, e) activating at least one of the modems in the second modem pool, f) deactivating at least one of the modems in the first modem pool, for at least one target modem in the second modem pool g) activating the second modem pool NEXT canceller filter, and h) measuring the NEXT transfer function for the target modem and at least one other disturbType: GrantFiled: November 27, 2000Date of Patent: March 6, 2007Assignee: Actelis Networks Ltd.Inventors: Amir Kantschuk, Dan Goren, Sharon Peleg, Maya Bar-El
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Patent number: 7180936Abstract: A method for preventing false starts during a handshake session involves the use of service identifiers for modem devices. The identifications are provided to one another for subsequent communication. To commence communications, a local device generates a request signal to initiate a handshake session. The request signal includes an identification unique to the remote device. The remote device receives the request and verifies the identification. The remote device then sends a response, which may optionally include an identification unique to the local device. The local device receives the response and verifies the identification before completing the handshake session.Type: GrantFiled: March 15, 2001Date of Patent: February 20, 2007Assignee: Centillium Communications, Inc.Inventors: Guozhu Long, Syed Abbas
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Patent number: 7167511Abstract: In a communications system having a modem pool including native modems operating at steady state, a method is provided for modem wake-up at steady-state including measuring modem performance, activating a foreign modem at substantially the foreign modem's maximum data rate and at a power level that is below the foreign modem's normal operational power level, allocating a NEXT cancellation filter as a probe filter, iteratively, until the foreign modem is operating at its normal operational power level, or the modem performance of any of the native modems has degraded subsequent to activating the foreign modem, canceling, using the probe filter, NEXT caused to a native modem by the foreign modem, measuring modem performance, and, if the modem performance of any of the native modems has not degraded, increasing the foreign modem's power level, and, if the modem performance of any of the native modems has degraded, deactivating the foreign modem.Type: GrantFiled: November 28, 2000Date of Patent: January 23, 2007Assignee: Actelis Networks IncInventors: Dan Goren, Amir Kantschuk
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Patent number: 7164648Abstract: An ultra-fast crosstalk cancellation technique characterizes crosstalk with a sample set representing NEXT generated by a single transmitted bit. During operation, transmit bit values of transmitted bits are saved in a transmit bit shift register and used to weight crosstalk samples corresponding to a stored transmit value. The weighted transmit samples are summed to generate a crosstalk cancellation signal which is subtracted from a received signal to remove NEXT.Type: GrantFiled: July 26, 2002Date of Patent: January 16, 2007Assignee: Cisco Technology, Inc.Inventors: Yuval Bachar, Gopakumar Parameswaran
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Patent number: 7158563Abstract: Methods, apparatus and systems for dynamically controlling a digital communication system, such as a DSL system, collect information about digital communication lines in the system and adaptively and/or dynamically determine line and signal characteristics of the digital communication lines, including interference effects. Based on the determined characteristics and the desired performance parameters, operation of the digital communication lines is adjusted to improve or otherwise control the performance of the system. The collection and processing of information may be performed by a party that is not a user in the system. This independent party also may control operational characteristics and parameters of the system. The invention can be used to eliminate or reduce signal interference such as crosstalk that can be induced on communication lines in systems such as DSL systems. Specific iterative power allocation and vectored transmission techniques and apparatus are disclosed.Type: GrantFiled: June 8, 2001Date of Patent: January 2, 2007Assignee: The Board of Trustees of the Leland Stanford Junior UniversityInventors: Georgios Ginis, Wei Yu, Chaohuang Zeng, John M. Cioffi
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Patent number: 7154845Abstract: A method for measuring crosstalk in a data service system includes transmitting a signal using a first device. The first device is coupled to a solid state crossbar switch. The method includes coupling the first device using the crossbar switch to a first data line coupled to the crossbar switch such that the signal communicates over the first data line. The first data line is capable of being coupled to a customer premise equipment (CPE) device. The method includes coupling a first number of second devices coupled to the crossbar switch to a second number of data lines coupled to the crossbar switch using the crossbar switch. Each second number of data lines is capable of being coupled to a CPE device. The method also includes monitoring the second number of data lines for near end crosstalk (NEXT) generated by the signal communicating over the first data line using the first number of second devices.Type: GrantFiled: May 3, 2002Date of Patent: December 26, 2006Assignee: Cisco Technology, Inc.Inventors: Hugh Barrass, Scott M. Simon
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Patent number: 7142501Abstract: A method and apparatus for eliminating near-end crosstalk in a communication network are disclosed. Crosstalk generated by communication occurring on a second line is detected on a first line and the phase of the crosstalk detected on the first line is determined. A first signal is communicated on the first line in response to the phase.Type: GrantFiled: December 26, 2001Date of Patent: November 28, 2006Assignee: Cisco Technology, Inc.Inventors: Hugh Barrass, Scott M. Simon
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Patent number: 7106833Abstract: An automatic system for the provisioning, deployment and management of digital subscriber lines (DSL) in a telephone network uses data on loop composition, electromagnetic interference and crosstalk between lines to optimize the performance and correct problems with one or more symmetric and or asymmetric digital subscriber lines in a cable. The system optimizes DSL lines on an individual basis using measurements and data. The optimal transmit power spectral density (PSD) for each DSL can be found in an iterative manner. Starting each DSL with some predetermined starting parameter, the transmit PSD of each DSL is optimized in round-robin fashion. The crosstalk into a given DSL is calculated as the power sum of all transmissions passed through their measured crosstalk couplings. An asymmetric DSL has its transmit PSD optimized by using the “waterfilling” technique.Type: GrantFiled: March 27, 2003Date of Patent: September 12, 2006Assignee: Telcordia Technologies, Inc.Inventor: Kenneth Kerpez
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Patent number: 7106688Abstract: A data communication system is provided that comprises a head-end switching system which comprises a plurality of communication ports. A port controller causes the ports to sequentially issue inquiry signals to network termination points. This sequential processing of inquiry signals prevents the formation of phantom links that may occur if physical conductors which are susceptible to crosstalk interference with connected conductors erroneously convey a response signal back to an unattached port within the head-in switching system.Type: GrantFiled: April 14, 2003Date of Patent: September 12, 2006Assignee: Cisco Technology, Inc.Inventors: Hugh Barrass, Brian A. Arnold
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Patent number: 7107031Abstract: The present invention relates to a method for a digital receiver and a receiver exploiting second order statistics for adaptive co-channel interference rejection in wireless communication. It uses digitally I, in phase, and Q, quadrature, branches of a received transmitted signal as input to the receiver, a coarse synchronization and a coarse frequency offset compensation have being performed on the signal. It comprises a means for derotation, means for separation, means for filtering, means for estimating and means for detecting transmitted symbols in the received signal. The invention thereby improving co-channel rejection in wireless communication, thus making it possible to increase the number of communication channels for frequencies used.Type: GrantFiled: May 30, 2001Date of Patent: September 12, 2006Assignee: Nokia CorporationInventors: Martin Kristensson, Bjorn Ottersten, Astel David
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Patent number: 7098821Abstract: In a wireless local area network (WLAN), receiving or transmitting signals having multiple modulation schemes can require the use of multiple clock rates. Providing these multiple clock rates significantly increases silicon area and power consumption, both of which are highly undesirably in a wireless device. A sequencing interpolator can advantageously reduce the number of clock rates by receiving signals at a first rate and outputting signals at a second rate. The sequencing interpolator can include a multiplexer network that selectively determines which coefficients are applied to certain signals. Coefficients are chosen to ensure that an error in a frequency domain is within a given tolerance. The multiplexer network can be controlled by a counter value. At a predetermined count, the interpolated output signal is discarded and the counter is reset.Type: GrantFiled: February 14, 2003Date of Patent: August 29, 2006Assignee: Atheros Communications, Inc.Inventors: Paul J. Husted, Tao-Fei Samuel Ng
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Patent number: 7099282Abstract: Empirically derived models are used to relate user perception to objectively measurable characteristics, under a criterion of nearly perfect co-variance between predicted MOS values and the variations in the values of the objectively measurable characteristics. In the example context of evaluating packet switched telephony service, the present invention eliminates the need to perform subjective tests to characterize each combination of codec type and transmission protocol.Type: GrantFiled: May 30, 2001Date of Patent: August 29, 2006Assignee: MCI, Inc.Inventor: William Christopher Hardy
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Patent number: 7099371Abstract: The present invention relates to an orthogonal spreading code in a code division multiple access (CDMA) mobile communication system, and more particularly, to a method for generating and allocating code or code pairs on the basis of an orthogonal code set, which is generated using orthogonal spreading codes, so as to reduce a peak-to-average power ratio and enlarge the length of an interference free window. In accordance with the invention, at least one orthogonal code set is generated based upon orthogonal spreading codes, one of the at least one orthogonal code set is determined as a representative orthogonal code set, and then the order is allocated according to rules determined based upon the representative orthogonal code set. The codes or code pairs are generated and allocated using the orthogonal spreading codes, so as to reduce a Peak-to-Average Power Ratio or extend the length of an interference free window (IFW).Type: GrantFiled: December 28, 2001Date of Patent: August 29, 2006Assignee: LG Electronics Inc.Inventor: Dong Wook Roh
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Patent number: 7089030Abstract: Systems and techniques are disclosed relating to communications. The systems and techniques involve transmitting to a remote location a first signal at a first energy level followed by a second signal at a second energy level, determining a target transmission energy level as a function of a target quality parameter at the remote location, and computing the second energy level as a function of the target transmission energy level and the first energy level. It is emphasized that this abstract is provided solely to assist a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.Type: GrantFiled: August 19, 2003Date of Patent: August 8, 2006Assignee: QUALCOMM IncorporatedInventors: Alkinoos Hector Vayanos, Durga Prasad Malladi, Da-shan Shiu
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Patent number: 7081764Abstract: An alien cross-talking testing system employs a plurality of alien cross-talk test signal units, an alien cross-talk measurement unit and an interconnection base unit. Each alien cross-talk test signal unit is in electrical communication with a different disturber cable to participate in a transmission of a RF test signal thereon. The alien cross-talk measurement unit is in electrical communication with a victim cable to measure an alien cross-talk signal generated on the victim cable in response to any alien cross-talk coupling between the victim cable and one or more of the disturber cables. The interconnection base unit is in electrical communication with the alien cross-talk measurement unit and the plurality of alien cross-talk test signals units to control non-simultaneous transmissions by the plurality of alien cross-talk test signal units of the RF test signals at a same frequency on the disturber cables as commanded by the alien cross-talk measurement unit.Type: GrantFiled: December 8, 2005Date of Patent: July 25, 2006Assignee: Agilent Technologies, Inc.Inventors: Harshang Pandya, Xing Zhu
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Patent number: 7081762Abstract: A method and apparatus are provided for measuring high speed glitch energy between first and second. The method and apparatus induce a change in charge on the first node from a first charge level to a second charge level with glitch energy supplied by the second node. An amount of charge is then supplied to the first node to restore the charge on the first node from the second charge level toward the first charge level. A representation of the amount of charge supplied to the first node is measured.Type: GrantFiled: July 31, 2003Date of Patent: July 25, 2006Assignee: LSI Logic CorporationInventors: John L. McNitt, Scott C. Savage
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Patent number: 7081763Abstract: An alien cross-talk method involves a victim cable and one or more disturber cables. The method encompasses a transmission of a RF test signal on each disturber cable between an alien cross-talk test signal unit connected to one end of a disturber cable and another alien cross-talk test signal unit connected to the other end of the disturber cable. The method further involves a measurement of an alien cross-talk signal generated on the victim cable in response to each cross-talk coupling of the victim cable and the disturber cable(s) based on the transmission of the RF test signal(s) on the disturber cable(s). The RF test signal(s) can be in the form of a RF frequency sweep and the measurement of the alien cross-talk signal can involve an execution of a RF frequency measurement sweep for acquiring samples of the alien cross-talk signal generated on the victim cable.Type: GrantFiled: August 3, 2005Date of Patent: July 25, 2006Assignee: Agilent Technologies, Inc.Inventors: Xing Zhu, Harshang Pandya, Kanwaljeet Singh
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Patent number: 7050388Abstract: Signals propagating in one communication channel can generate crosstalk interference in another communication channel. A crosstalk cancellation device can process the signals causing the crosstalk interference and generate a crosstalk cancellation signal that can compensate for the crosstalk when applied to the channel receiving crosstalk interference. The crosstalk cancellation device can include a model of the crosstalk effect that generates a signal emulating the actual crosstalk both in form an in timing. The crosstalk cancellation device can include a controller that monitors crosstalk-compensated communication signals and adjusts the model to enhance crosstalk cancellation performance. The crosstalk cancellation device can have a mode of self configuration or calibration in which defined test signals can be transmitted on the crosstalk-generating channel and the crosstalk-receiving channel.Type: GrantFiled: August 5, 2004Date of Patent: May 23, 2006Assignee: Quellan, Inc.Inventors: Andrew Joo Kim, Michael G. Vrazel, Sanjay Bajekal, Charles Summers
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Patent number: 7046798Abstract: The present invention provides methods and apparatus for transmitting a data-bearing signal and a non-data-bearing signal. One embodiment comprises communicatively coupling a data-bearing signal during a first time period and communicatively coupling a non-data-bearing signal during a second time period. The data-bearing signal has a first PSD. The non-data-bearing signal has a second PSD substantially the same as the first over a range of frequencies. The non-data-bearing signal has characteristics facilitating echo cancellation. Another embodiment comprises a line interface and a transmitter coupled to the line interface, comprising a data encoder and a periodic signal generator. The encoder is configured to produce a data-bearing signal with a first PSD. The periodic signal generator is configured to produce a non-data-bearing signal with a second PSD. The second PSD is substantially the same as the first PSD over a first range of frequencies.Type: GrantFiled: September 3, 2003Date of Patent: May 16, 2006Assignee: Paradyne CorporationInventors: William L. Betts, Gordon F. Bremer, Rafael S. Martinez
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Patent number: 7046751Abstract: In a communications system having a modem pool for communicating via a communications channel, the modem pool including a plurality of modems and having a plurality A of NEXT cancellation filters, a) measuring NEXT impairment caused to at least one target modem among the plurality of modems by at least one disturber modem among the plurality of modems, b) allocating P filters among the A filters as probe filters, where P>=1, c) allocating at least one of the remaining A?P filters among the filters to cancel NEXT from at least one disturber modem among the plurality of modems, and d) measuring, using at least one of the P probe filters, NEXT impairment caused to at least one target modem among the plurality of modems by at least one candidate disturber modem among the plurality of modems to which no A?P filter is currently allocated.Type: GrantFiled: November 27, 2000Date of Patent: May 16, 2006Assignee: Actelis Networks Inc.Inventors: Amir Kantschuk, Sharon Peleg, Maya Bar-El, David Vaaknin, Gilad Rozen
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Patent number: 7042934Abstract: In a modem pool system capable of mitigating alien crosstalk, a system including a first modem pool including at least two modems, at least one protected line connected to one of the modems, at least one sensor line connected to another of the modems, at least one alien crosstalk predictor operative to sample an alien signal on the at least one sensor line and provide an alien crosstalk prediction signal, and at least one alien crosstalk prediction summation element operative to receive the alien crosstalk prediction signal from the alien crosstalk predictor and subtract the alien crosstalk prediction signal from a data transmission signal on the protected line.Type: GrantFiled: January 23, 2002Date of Patent: May 9, 2006Assignee: Actelis Networks Inc.Inventor: Ram Zamir
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Patent number: 7035400Abstract: An improved system and method for communicating information on a transmission medium is disclosed. The disclosed system and method provide improved communications on the transmission medium in the presence of interference, which may take the form of uncorrelated interference from different services on neighboring transmission mediums. In one embodiment, the communications system includes a subscriber modem, a central office modem; and a communications channel coupled between the subscriber modem and the central office modem. The communications channel transports uplink signals from the subscriber modem to the central office modem, and downlink signals from the central office modem to the subscriber modem.Type: GrantFiled: February 21, 2000Date of Patent: April 25, 2006Assignee: Wm. Marsh Rice UniversityInventors: Rohit V. Gaikwad, Richard G. Baraniuk
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Patent number: 7027537Abstract: Methods and mechanisms for reducing the impact of cross talk interference in multi-carrier data transmission systems are disclosed. In one aspect, the invention relates to a method of canceling cross talk interference in a received data signal. The method includes receiving an input signal that includes a primary data signal and a superimposed cross-talk signal. An estimation of the primary data signal and an estimation of the superimposed cross talk signal are iteratively computed. The probable estimation of the primary data signal is based at least in part upon the iteratively computed probable estimation of the cross talk signal and the probable estimation of the superimposed cross talk signal is based at least in part upon the iteratively computed probable estimation of the primary data signal.Type: GrantFiled: March 3, 2000Date of Patent: April 11, 2006Assignee: The Board of Trustees of the Leland Stanford Junior UniversityInventors: Kok-Wui Cheong, Won-Joon Choi, Johnny Li-Shung Fan, Zining Wu, John M. Cioffi
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Patent number: 7023937Abstract: A receiver window design algorithm (210) is developed which minimizes the noise power of the demodulated multicarrier signal. The windows are effective on a variety of different channels and noise sources. Receiver windowing is a computationally efficient technique for reducing noise spreading in multicarrier communication systems.Type: GrantFiled: March 1, 2001Date of Patent: April 4, 2006Assignee: Texas Instruments IncorporatedInventor: Arthur John Redferm
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Patent number: 7023910Abstract: A dual-line DSL system comprises a central office and a customer premises coupled by at least two communication paths that together provide a single high-bandwidth channel. An ADSL transceiver unit-remote (ATU-R) at the customer premises is configured to reduce the effects of far end cross talk and near end cross talk on signals received by the ATU-R.Type: GrantFiled: December 19, 2001Date of Patent: April 4, 2006Assignee: 2Wire, Inc.Inventor: Andrew L. Norrell
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Patent number: 7020068Abstract: A cancellation system comprises a channel circuit (11) for each noise source, such as echo in a particular cable pair. There are only eighty taps per channel, in two blocks (n_echo_a, f_echo_a). Each block is preceded by a variable delay line comprising blocks of registers cascaded so that a delay value of 0 to 40 clock cycles can be chosen. The delay value is determined by determining an optimum position for each tap block. This is achieved by determining a maximum coefficient sum for a number of windows. Taps from other channels are used during training, so that there is a total of 160 taps for each channel during training to enable the optimum positions to be determined.Type: GrantFiled: April 30, 2001Date of Patent: March 28, 2006Assignee: Massana Research LimitedInventors: Philip Curran, Albert Molina, Brian Murray, Carl Murray
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Patent number: 7002930Abstract: A method of optimally distributing signal power for multiple users over a xDSL or wireless channel considers uses computationally efficient tools to achieve improved crosstalk avoidance. The method chooses between EQPSD and FDS signaling in a fashion that maximizes overall data rate. Rather than choosing EQPSD signaling in regions where there is low self-NEXT, but where the echo is high (relative to signal power), the method selects FDS signaling since the communication system acts in a manner similar to self-NEXT in such regions.Type: GrantFiled: October 19, 2001Date of Patent: February 21, 2006Assignee: Texas Instruments IncorporatedInventors: Nadeem Ahmed, Donald Phillip Shaver, Arthur Redfern
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Patent number: 7002897Abstract: A method and apparatus for reducing crosstalk in a multi-channel communication system is disclosed. In one embodiment, outgoing signals in a multi-channel environment are manipulated into a transform domain, such as the frequency domain. Thereafter, the signals may be combined and modified based on a weighting variable to create a cancellation signal. Combined processing greatly reduces system complexity and increases processing speed. After processing in the transform domain, the cancellation signal undergoes further processing to return the cancellation signal into the time domain. The cancellation signal may then be combined with received signals to cancel crosstalk or echo. A method and apparatus for crosstalk cancellation in the analog domain and digital domain is also disclosed.Type: GrantFiled: April 28, 2003Date of Patent: February 21, 2006Assignee: SolarFlare Communications, Inc.Inventors: William W. Jones, George A. Zimmerman
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Patent number: 7003602Abstract: In apparatuses (1, 2, 3) controlled or operated via an I2 C bus, it may be necessary to take measures to suppress interference signals at the data signal input/output of the respective apparatus without impairing the data transport at the same time. The data line at the data signal input/output contains an RC element, in the form of a low-pass filter, with a diode connected in parallel with the RC element, the low-pass filter action allowing the arrangement to be used to suppress interference signals acting on the data signal input/output, and, secondly, the transmissive action of the diode meaning that the arrangement does not impair a data signal leaving the data signal input/output.Type: GrantFiled: November 19, 2001Date of Patent: February 21, 2006Assignee: Thomson LicensingInventors: Alfred Selz, Veit Armbruster
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Patent number: 6999517Abstract: A digital telemetry system having improved data rate and robustness. The telemetry system has a data transmission cable having a first end and a second end, and is capable of transmitting data between the first and second end on at least two propagation modes. A data source connected at the first end has data transmission circuitry to generate data signals on these propagation modes. A receiver connected to the second end of the wireline cable has a first receive circuitry to receive signals on a first of the at least two propagation modes and a second receive circuitry to receive signals on a second of the at least two propagation modes. An adaptive far-end cross-talk cancellation circuitry connected to the first receive circuitry and to the second receive circuitry cancels out far-end cross-talk between the at least two propagation modes.Type: GrantFiled: June 7, 2000Date of Patent: February 14, 2006Assignee: Sehlumberger Technology CorporationInventors: Bart J. Bombay, Lloyd D. Clark, Jr.
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Patent number: 6999583Abstract: Crosstalk between subscriber loops used to transmit different broadband services through the same bundled telephone cable is a significant limitation to providing digital subscriber line services. A method for estimating the crosstalk, identifying the sources of the crosstalk and predicting additional sources of crosstalk are disclosed. The crosstalk sources are identified in the frequency domain by maximizing the correlation with a “basis set” of received crosstalk PSDs which consist of the cascade of a finite set of known transmit PSDs types times a representative set of crosstalk couplings. Multiple crosstalk types are identified with a technique of successive spectral subtraction. This information can be used to perform crosstalk cancellation and spectrum management for DSL systems.Type: GrantFiled: August 3, 2001Date of Patent: February 14, 2006Assignee: Telcordia Technologies, Inc.Inventors: Craig F. Valenti, Kenneth Kerpez
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Patent number: 6999504Abstract: A method and apparatus are disclosed for reducing crosstalk in a telecommunication system. Broadly, the present invention utilizes a common mode signal to obtain additional information that can be used to better approximate the transmitted signal (by approximating and canceling crosstalk or otherwise). In accordance with one embodiment of the invention, a modem is provided having improved crosstalk cancellation circuitry for canceling crosstalk received on a local loop (or otherwise estimating the remotely transmitted signal) carrying modem communications. The modem includes a first input for receiving a signal carried on the local loop and a second input for receiving a signal obtained from the common mode. The modem further includes processing circuitry configured to either reduce crosstalk present in the signal carried on the local loop, or to otherwise closely approximate the remotely transmitted signal.Type: GrantFiled: March 15, 2001Date of Patent: February 14, 2006Assignee: GlobespanVirata, Inc.Inventors: Daniel Amrany, Patrick Duvaut, William Keasler, Laurent Pierrugues
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Patent number: 6990196Abstract: Methods, apparatus and systems for identifying crosstalk interference in xDSL systems are disclosed and are useful in a variety of xDSL systems to assist in the provisioning, maintenance and diagnosis of the xDSL system and in spectral management and assignments. Signal data are collected from a receiver, a primary transmitter and any crosstalk transmitters. The signal data are resampled, if necessary. A first estimate of the timing offset between the received signal and each crosstalk signal is then obtained by cross-correlating the received data with the transmitted crosstalk data. The first timing offset estimate is then used in connection with a least-squares estimation of the crosstalk response for the considered crosstalk data and a second estimate of the timing offset. The invention may be used at a third party site remote from the system transmitters and receivers. The crosstalk identification of the present invention can be used in dynamic spectrum management for DSL services and signals.Type: GrantFiled: February 16, 2001Date of Patent: January 24, 2006Assignee: The Board of Trustees of the Leland Stanford Junior UniversityInventors: Chaohuang Zeng, Carlos Aldana, Atul Salvekar, John M. Cioffi
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Patent number: 6970415Abstract: A method and apparatus for identification of interference sources are disclosed.Type: GrantFiled: November 10, 2000Date of Patent: November 29, 2005Assignee: Tokyo Electron LimitedInventors: Cecilia Gabriela Galarza, Michail Tsatsanis, Mark Alan Erickson, Ioannis Kanellakopoulos, James W. Waite, Ming Gu, Sunil C. Shah, Daniel Joseph Hernandez, Thomas E. Paré, Jr., Norman Man Leung Yuen
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Patent number: 6970516Abstract: A system generally having a first circuit, a second circuit, and a pair of non-crossing conductive paths. The first circuit may be configured to convert between (i) a serial signal on a first differential interface and (ii) a parallel signal. The pair of non-crossing conductive paths may connect the first differential interface with a second differential interface. The second circuit may be configured to invert the parallel signal in response to a control signal in an inverting state.Type: GrantFiled: August 29, 2001Date of Patent: November 29, 2005Assignee: LSI Logic CorporationInventors: Steven A. Schauer, Christopher D. Paulson
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Patent number: 6950515Abstract: Provided is an asymmetric digital subscriber line (ADSL) system that communicates via digital subscriber line (DSL) routing through a bundle of cables including a communication line for time compression multiplexing-integrated services digital network (TCM-ISDN) system that is synchronized with a TCM timing reference (TTR) signal. The ADSL system is synchronized with a data signal inputted after the TTR indication signal.Type: GrantFiled: January 8, 2003Date of Patent: September 27, 2005Assignee: Samsung Electronics, COInventor: Jung-Joo Lee
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Patent number: 6915249Abstract: In order to achieve augmentation of the accuracy in calculation of noise and augmentation of the accuracy in a noise check which is performed, for example, when an electronic circuit is designed and further realize significant reduction of the time required for a noise check and augmentation of the operation efficiency by reduction of the man-hours of a designer in a noise analysis, a noise checking apparatus includes a model production section (3) for producing a simulation model of a circuit portion relating to a noticed wiring line, a simulation section (4) for performing a simulation using the simulation model to calculate a signal waveform which propagates in the noticed wiring line and calculate a noise waveform superposed on the signal waveform for each kind of noise, a noise waveform synthesis section (5) for synthesizing the signal waveform and the noise waveforms with generation timings of the noise waveforms taken into consideration to obtain a noise composite waveform, and a noise checking sectionType: GrantFiled: November 9, 2000Date of Patent: July 5, 2005Assignee: Fujitsu LimitedInventors: Toshiro Sato, Yuji Suwa, Yoshiyuki Iwakura, Kazunari Gotou, Toshiaki Sato, Kazuyoshi Kanei, Masaki Tosaka, Yasuhiro Yamashita
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Patent number: 6891857Abstract: A collection of wirelessly networked devices including first devices wirelessly networked together using a first wireless protocol that is a frequency hopping protocol, and second devices wirelessly networked together using a second wireless protocol, are operated in a coordinated manner, including proactive reduction of interference between the networked devices. In one embodiment, the first devices include at least a first and a second subset operating with a first and a second frequency hopping pattern respectively. The proactive reduction effort includes synchronized operations of the first and second subsets of the first devices, and the second devices operate in a manner complementary to the synchronized operations of the first devices. In one embodiment, the collection of wirelessly networked devices includes at least one wireless device that operates in both wireless networks in accordance with both wireless protocols.Type: GrantFiled: April 27, 2000Date of Patent: May 10, 2005Assignee: Intel CorporationInventors: Ron Nevo, Enhraim Zehavi, Xudong Zhao, Ran Ginosar
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Patent number: 6885746Abstract: Crosstalk between subscriber loops used to transmit different broadband services through the same bundled telephone cable is a significant limitation to providing digital subscriber line services. A method for estimating the crosstalk, identifying the sources of the crosstalk and predicting additional sources of crosstalk are disclosed. The crosstalk sources are identified in the frequency domain by maximizing the correlation with a “basis set” of received crosstalk PSDs which consist of the cascade of a finite set of known transmit PSDs types times a representative set of crosstalk couplings. Multiple crosstalk types are identified with a technique of successive spectral subtraction. Once a type is identified the crosstalk disturber is compared against all other members of the complete set for that type. Additionally, Mutliple Regression (MR) techniques and a Matching Pursuit (MP) algorithm are used to increase the ability of the system and method to identify various crosstalk disturbers.Type: GrantFiled: July 31, 2002Date of Patent: April 26, 2005Assignee: Telecordia Technologies, Inc.Inventors: Robert Hausman, Stefano Galli, Kenneth Kerpez
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Patent number: 6870807Abstract: The subject invention is directed to a method and system for removing music or other unwanted noise from a conference call particularly when the music or other unwanted noise is not directly under the control of the telecommunication equipment the user is attached to and using. The method and system detects the unwanted sound, deactivates the sound source or disconnects from the line carrying the sound, monitors the disconnected line for voice energy, and reconnects the line when voice energy is detected. This capability provides the telecommunications equipment user with control over unwanted music sources being provided by equipment located either in the private or public networks.Type: GrantFiled: May 15, 2000Date of Patent: March 22, 2005Assignee: Avaya Technology Corp.Inventors: Norman C. Chan, Rickie E. Meis
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Patent number: 6859508Abstract: A multidimensional equalizer and cross talk canceller for a communication network that simultaneously removes far end cross talk NEXT) and intersymbol interference (ISI) from a received signal. A multidimensional-pair channel is treated as a single multidimensional channel and a receiver in the communication network equalizes received signals through the use of the multidimensional equalizer. A decision feedback equalizer determines a multidimensional steepest descent gradient to adjust matrix coefficients.Type: GrantFiled: September 28, 2000Date of Patent: February 22, 2005Assignee: NEC Electronics America, Inc.Inventors: Tetsu Koyama, Jason Peng, Paul E. Cohen