Patent application number | Description | Published |
20090148164 | SIGNAL EQUALIZER IN A COHERENT OPTICAL RECEIVER - A signal equalizer for compensating impairments of an optical signal received through a link of a high speed optical communications network. At least one set of compensation vectors are computed for compensating at least two distinct types of impairments. A frequency domain processor is coupled to receive respective raw multi-bit in-phase (I) and quadrature (Q) sample streams of each received polarization of the optical signal. The frequency domain processor operates to digitally process the multi-bit sample streams, using the compensation vectors, to generate multi-bit estimates of symbols modulated onto each transmitted polarization of the optical signal. The frequency domain processor exhibits respective different responses to each one of the at least two distinct types of impairments. | 06-11-2009 |
20090201796 | LOW CONVERSION RATE DIGITAL DISPERSION COMPENSATION - A method of suppressing effects of aliasing in a system for digitally processing a high speed signal having a symbol rate of 1/T. The high speed signal is sampled at a fractional multiple (N) of the symbol rate, wherein 108-13-2009 | |
20100067902 | OPTICAL TRANSMITTER ERROR REDUCTION USING RECEIVER FEEDBACK - Described is a method of reducing transmitter error in an optical communications channel. An optical signal transmitted from an optical transmitter that has impairment due to transmitter error is processed to generate a digitally-equalized signal. A nonlinear characteristic of the digitally-equalized signal that relates to the transmitter error is determined. An optical control signal comprising data that are based on the nonlinear characteristic is transmitted to the optical transmitter. The optical transmitter modifies a transmitter parameter in response to the optical control signal to change the nonlinear characteristic and thereby reduce the impairment. | 03-18-2010 |
20100092181 | LOW CONVERSION RATE DIGITAL DISPERSION COMPENSATION - A method of suppressing effects of aliasing in a system for digitally processing a high speed signal having a symbol rate of 1/T. The high speed signal is sampled at a fractional multiple (N) of the symbol rate, wherein 104-15-2010 | |
20100138722 | CYCLE SLIP LOCATION AND CORRECTION - Methods and techniques are disclosed for correcting the effect of cycle slips in a coherent communications system. A signal comprising SYNC bursts having a predetermined periodicity and a plurality of known symbols at predetermined locations between successive SYNC bursts is received. The received signal is partitioned into data blocks. Each data block encompasses at least data symbols and a set of check symbols corresponding to the plurality of known symbols at predetermined locations between a respective pair of successive SYNC bursts in the signal. Each data block is processed to detect a cycle slip. When a cycle slip is detected, the set of check symbols of the data block are examined to identify a first slipped check symbol, and a phase correction applied to data symbols of the data block lying between the first slipped check symbol and an end of the data block. | 06-03-2010 |
20110243573 | SIGNAL EQUALIZER IN A COHERENT RECEIVER - A signal equalizer for compensating impairments of an optical signal received through a link of a high speed optical communications network. At least one set of compensation vectors are computed for compensating at least two distinct types of impairments. A frequency domain processor is coupled to receive respective raw multi-bit in-phase (I) and quadrature (Q) sample streams of each received polarization of the optical signal. The frequency domain processor operates to digitally process the multi-bit sample streams, using the compensation vectors, to generate multi-bit estimates of symbols modulated onto each transmitted polarization of the optical signal. The frequency domain processor exhibits respective different responses to each one of the at least two distinct types of impairments. | 10-06-2011 |
20130136450 | SIGNAL EQUALIZER IN A COHERENT OPTICAL RECEIVER - A signal equaliser for compensating impairments of an optical signal received through a link of a high speed optical communications network. At least one set of compensation vectors are computed for compensating at least two distinct types of impairments. A frequency domain processor is coupled to receive respective raw multi-bit in-phase (I) and quadrature (Q) sample streams of each received polarization of the optical signal. The frequency domain processor operates to digitally process the multi-bit sample streams, using the compensation vectors, to generate multi-bit estimates of symbols modulated onto each transmitted polarization of the optical signal. The frequency domain processor exhibits respective different responses to each one of the at least two distinct types of impairments. | 05-30-2013 |
20140092924 | CHANNEL CARRYING MULTIPLE DIGITAL SUBCARRIERS - An optical system includes a transmitter module and/or a receiver module. The transmitter module is configured to receive input data, map the input data to a set of subcarriers associated with an optical communication channel, independently apply spectral shaping to each of the subcarriers, generate input values based on the spectral shaping of each of the subcarriers, generate voltage signals based on the input values, modulate light based on the voltage signals to generate an output optical signal that includes the subcarriers, and output the output optical signal. The receiver module is configured to receive the output optical signal, convert the output optical signal to a set of voltage signals, generate digital samples based on the set of voltage signals, independently process the digital samples for each of the subcarriers, map the processed digital samples to produce output data, and output the output data. | 04-03-2014 |
20140133868 | INTENSITY-BASED MODULATOR - An optical modulator includes a splitter, phase modulators, amplitude modulators, intensity modulators, and a combiner. The splitter is configured to receive light, and split the light into portions of the light. Each of the phase modulators is configured to receive a corresponding one of the portions of the light, and modulate a phase of the portion of the light to provide a phase-modulated signal. Each of the amplitude modulators is configured to receive a corresponding one of the phase-modulated signals, and modulate an amplitude of the phase-modulated signal to provide an amplitude-modulated signal. Each of the intensity modulators is configured to receive a corresponding one of the amplitude-modulated signals, and modulate an intensity of the amplitude-modulated signals to provide an intensity-modulated signal. The combiner is configured to receive the intensity-modulated signals, combine the intensity-modulated signals into a combined signal, and output the combined signal. | 05-15-2014 |
20150188641 | POWER-EFFICIENT MAXIMUM LIKELIHOOD DECODING FOR 5 BITS PER DUAL-POL-SYMBOL MODULATION - A digital signal processor (DSP), may identify symbol values associated with a 5 quadrature amplitude modulation (5QAM) signal. The DSP may determine a first bit set based on the symbol values and a first particular bit value. The DSP may determine a second bit set based on the symbol values and a second particular bit value. The DSP may compute a first distance based on the first bit set and the symbol values. The DSP may compute a second distance based on the second bit set and the symbol values. The DSP may determine that the first distance is less than the second distance. The first distance being less than the second distance may indicate that the first bit set is a correctly decoded bit set. The DSP may provide an output associated with the correctly decoded bit set. | 07-02-2015 |
20150311919 | CODE DESIGN AND HIGH-THROUGHPUT DECODER ARCHITECTURE FOR LAYERED DECODING OF A LOW-DENSITY PARITY-CHECK CODE - A low-density parity-check (LDPC) decoder may receive LDPC coded data. The LDPC decoder may perform a decoding iteration associated with decoding the LDPC coded data. The decoding iteration may be performed by processing a group of layers. Each layer may include a corresponding set of check node elements, and may be processed by causing each check node element, of the set of check node elements corresponding to the layer, to update a set of variable node elements, connected to the check node element and associated with the LDPC coded data, based on a check node function associated with the check node element. The decoding iteration may be performed such that each layer is processed in parallel, and such that each check node element updates the corresponding set of variable node elements in parallel. The LDPC decoder may provide a result of performing the decoding iteration. | 10-29-2015 |
20150333837 | TRACKING NONLINEAR CROSS-PHASE MODULATION NOISE AND LINEWIDTH INDUCED JITTER IN COHERENT OPTICAL FIBER COMMUNICATION LINKS - An optical receiver may include a digital signal processor to receive an input sample that includes transmitted data, transmitted by an optical transmitter, and nonlinear distortion. The digital signal processor may process the input sample to generate an estimated data value. The estimated data value may be an estimate of the transmitted data. The digital signal processor may remove the estimated data value from the input sample to generate a noise sample. The digital signal processor may determine a nonlinear distortion value based on the input sample, the estimated data value, and the noise sample. The nonlinear distortion value may be an estimate of the nonlinear distortion included in the input sample. The digital signal processor may remove the nonlinear distortion value from the input sample to generate an output sample, and may output the output sample. | 11-19-2015 |
20150381315 | PARTITIONING FORWARD ERROR CORRECTION DECODING ITERATIONS TO ACCOMMODATE MULTIPLE DATA STREAMS - An optical receiver may receive a data stream, and may decode the data stream using a first iterative forward error correction (FEC) decoder. The optical receiver may determine whether to further decode the data stream using the first iterative FEC decoder or a second iterative FEC decoder that is different from the first iterative FEC decoder. The optical receiver may selectively perform a first action or a section action based on determining whether to further decode the data stream. The first action may include providing the data stream to the first iterative FEC decoder or the second iterative FEC decoder for further decoding when the data stream is to be further decoded. The second action may include preventing the data stream from being provided to the first iterative FEC decoder or the second iterative FEC decoder when the data stream is not to be further decoded. | 12-31-2015 |
20160028481 | SIGNAL EQUALIZER IN A COHERENT OPTICAL RECEIVER - A signal equalizer for compensating impairments of an optical signal received through a link of a high speed optical communications network. At least one set of compensation vectors are computed for compensating at least two distinct types of impairments. A frequency domain processor is coupled to receive respective raw multi-bit in-phase (I) and quadrature (Q) sample streams of each received polarization of the optical signal. The frequency domain processor operates to digitally process the multi-bit sample streams, using the compensation vectors, to generate multi-bit estimates of symbols modulated onto each transmitted polarization of the optical signal. The frequency domain processor exhibits respective different responses to each one of the at least two distinct types of impairments. | 01-28-2016 |
Patent application number | Description | Published |
20140294381 | ADJUSTING CARRIER SPACING IN A CHANNEL - An optical system may include optical transmitters to provide respective optical signals. Each of the respective optical signals may provide one or more carriers in an optical channel. The optical channel may include multiple carriers associated with the respective optical signals. First and second carriers, of the multiple carriers, may have a particular carrier space width. The particular carrier space width may include a frequency error associated with one or more optical signals of the respective optical signals. The optical system may include a control system to determine the frequency error and cause one or more of the optical transmitters to adjust the particular carrier space width based on the adjusted frequency error. | 10-02-2014 |
20140308039 | EQUALIZING A SIGNAL MODULATED USING A 5QAM MODULATION FORMAT - An optical system may include an optical transmitter or an optical receiver. The optical transmitter may include a laser to provide an input signal, a first digital signal processor (DSP) to receive a data signal, provide non-rotated and rotated symbols corresponding to the data signal, and provide digital signals corresponding to the non-rotated and the rotated symbols to cause one or more digital to analog converts to convert the digital signals to analog signals. The optical transmitter may further provide a modified 5 quadrature amplitude modulation (5QAM) signal based on the analog signals and the input signal. A constellation map of the modified 5QAM signal may include all constellation points of a 16QAM signal. The optical receiver may include a second DSP to receive components associated with the 5QAM signal, filter the components, reduce phase noise of the 5QAM signal, and provide data associated with the 5QAM signal. | 10-16-2014 |
20140328584 | REDUCING PHASE NOISE ASSOCIATED WITH OPTICAL SOURCES - An optical transmitter may include an optical source to provide a first optical signal having a varying frequency; an optical circuit to receive a portion of the first optical signal and provide a second optical signal corresponding to a change in frequency of the first optical signal; a photodetector to receive the first optical signal and provide an electrical signal that is indicative of the change in frequency of the first optical signal; an integrator to receive the electrical signal and provide an inverted electrical signal; and a controller to process the inverted electrical signal and provide a current, associated with the inverted electrical signal, to the optical source. The optical source may reduce the phase noise associated with the first optical signal based on the current. | 11-06-2014 |
20150023659 | CLOCK PHASE DETECTION IN THE FREQUENCY DOMAIN - A digital signal processor (DSP) may receive samples of a signal from an analog-to-digital converter (ADC); convert the samples from a time domain to a frequency domain; determine a clock phase error of the samples while in the frequency domain; and provide a voltage corresponding to the clock phase error. The voltage may be provided to reduce timing errors associated with the samples. | 01-22-2015 |
20150030333 | HAMMING CODED MODULATION - An optical system may include a digital signal processor (DSP) to receive first samples of a digital signal. The first samples may be Hamming encoded. The DSP may correlate the first samples to multiple groups of second samples to determine multiple correlation values. Each of the multiple groups of second samples may correspond to respective code words. Each of the multiple correlation values may correspond to a correlation measurement between the first samples and each of the multiple groups of second samples. The DSP may determine a particular code word, of the multiple code words, corresponding to one of the correlation values of the multiple correlation values; determine output bits based on bits of the particular code word and the one of the correlation values; and provide the output bits. The output bits may include data associated with the digital signal. | 01-29-2015 |
20150188642 | DETECTING AND CORRECTING CYCLE SLIPS TO MINIMIZE SYSTEM PENALTY - An optical receiver receives an optical signal with a phase error and pilot symbols, and converts the optical signal into an electrical signal. The optical receiver identifies, based on the pilot symbols, a cycle slip due to the phase error and associated with a transition time. The optical receiver determines, based on the pilot symbols, a direction and a center of the cycle slip, and generates a rotation value based on the direction and the center. The optical receiver applies the rotation value to minimize the phase error in the electrical signal except for phase error associated with the transition time and to generate a modified electrical signal. The optical receiver generates an erase signal based on the transition time and the center of the cycle slip, and uses the erase signal to minimize an effect of the phase error associated with the transition time of the cycle slip. | 07-02-2015 |
20150280814 | ESTIMATING PHASE USING TEST PHASES AND INTERPOLATION FOR MODULATION FORMATS USING MULTIPLE SUB-CARRIERS - An optical receiver may receive input signals carried by sub-carriers, and may apply test phases to each input signal. The optical receiver may determine error values, associated with test phases, for each input signal. The optical receiver may calculate updated metric values, associated with the test phases, for a particular input signal, based on a first error value and a second error value. The first error value may be associated with a first sub-carrier, and the second error value may be associated with a second sub-carrier. The optical receiver may compare the updated metric values associated with the particular input signal, and may determine a test phase that represents an estimated phase, associated with the particular input signal, based on the comparison. The optical receiver may determine a phase estimate value based on the test phase, and may provide the phase estimate value to modify the particular input signal. | 10-01-2015 |
20150280833 | ACCURATE CALCULATION OF POLARIZATION MODE DISPERSION USING BLIND EQUALIZATION - A digital signal processor (DSP) may receive a signal that has an x-polarization (x-pol) and a y-polarization (y-pol). The DSP may equalize the x-pol of the signal and the y-pol of the signal based on filter coefficients determined using a constant modulus algorithm (CMA). The DSP may perform phase correction on the equalized x-pol signal and the equalized y-pol signal. The DSP may identify a first frame header pattern within the phase-corrected x-pol signal, and may identify a second frame header pattern within the phase-corrected y-pol signal. The DSP may determine, based on the first frame header pattern and the second frame header pattern, a quantity of lock-in differential group delay (DGD). The device may adjust one or more of the filter coefficients to remove the quantity of lock-in DGD and to permit an amount of polarization mode dispersion to be determined based on the filter coefficients. | 10-01-2015 |
20150280834 | FREQUENCY AND PHASE COMPENSATION FOR MODULATION FORMATS USING MULTIPLE SUB-CARRIERS - An optical receiver may receive input signals carried by respective sub-carriers. The optical receiver may determine, based on the input signals, a compensation value to be used to modify an input signal. The optical receiver may use the compensation value to adjust the input signal to form a modified input signal. The compensation value may be used to modify a frequency or a phase of the input signal. The optical receiver may determine, based on the modified input signal, a phase estimate value that represents an estimated phase associated with the input signal. The optical receiver may combine the compensation value and the phase estimate value to form a phase adjustment signal, may combine the input signal and the phase adjustment signal to form an output signal, and may output the output signal. | 10-01-2015 |
20150280853 | CONFIGURABLE FREQUENCY DOMAIN EQUALIZER FOR DISPERSION COMPENSATION OF MULTIPLE SUB-CARRIERS - A system may include an optical transmitter and an optical receiver. The optical transmitter may generate optical signals associated with sub-carriers, and may provide the optical signals via an optical link. The optical receiver may receive the optical signals via the optical link, and may generate samples based on the optical signals. The samples may be associated with the sub-carriers. The optical receiver may combine the samples to form a time domain sample vector having a particular size, and may generate a frequency domain sample vector, having the particular size, based on the time domain sample vector. The optical receiver may demultiplex the frequency domain sample vector to generate domain sample vectors corresponding to the sub-carriers. The optical receiver may process the frequency domain sample vectors to generate equalized frequency domain sample vectors, and may output the equalized frequency domain sample vectors. | 10-01-2015 |
Patent application number | Description | Published |
20110291865 | METHOD, SYSTEM, AND APPARATUS FOR INTERPOLATING AN OUTPUT OF AN ANALOG-TO-DIGITAL CONVERTER - A system, method, and apparatus is disclosed for interpolation of an output of an analog to digital converter (ADC) to enable operation of the ADC at a sampling rate that is independent of the sampling rate for a DSP core so as to efficiently enable operation at higher date rates. According to one of the embodiments, an interpolation circuit is coupled between the ADC and DSP core and receives a first plurality of samples of data at the first data rate from the ADC and supplies a plurality of samples of second data at a second data rate to the DSP core; the second data rate being less than the first data rate. According to one of the embodiments, the interpolation circuit includes a memory and a FIR filter circuit having filter tap coefficient values selected to provide attenuation at high frequencies to reduce aliasing noise. | 12-01-2011 |
20110293289 | METHOD, SYSTEM, AND APPARATUS FOR BLIND EQUALIZATION OF BPSK SIGNALS - A system, method, and apparatus is disclosed for enabling a constant modulus algorithm (CMA) to be reliably used for blind equalization training of an equalizer. According to one embodiment, received signals in a binary phase shift keying (BPSK) format are converted to a quadrature phase shift keying (QPSK) format, to which CMA processing can be reliably applied for equalization. According to another aspect of this embodiment, the equalized QPSK signals are rotated to convert the signals to an equalized BPSK format for output. | 12-01-2011 |
20110318017 | METHOD, SYSTEM, AND APPARATUS FOR CARRIER SYNCHRONIZATION OF QAM MODULATED SIGNALS - Consistent with the present disclosure, optical signals are modulated in accordance with a higher order QAM modulation format, such as 8-QAM, to carry customer data, for example. The optical signals are converted to corresponding electrical signals, which are then subject to further processing. In particular, phase data associated with the higher order QAM constellation is processed, such that the outer points of the constellation are rotated to have the same phase as the inner points. As a result, both the inner and outer points resemble a constellation, and both may be more readily processed using feedforward or feedback carrier recovery. After such carrier recovery, the phase data is further processed so that the outer points are rotated back and the customer data can be extracted from the phase data. | 12-29-2011 |
20120086492 | FREQUENCY DOMAIN CLOCK RECOVERY - Consistent with an aspect of the present disclosure, an optical signal carrying data or information is supplied to photodetector circuitry that generates a corresponding analog signal. The analog signal may be amplified or otherwise processed and supplied to analog-to-digital conversion (ADC) circuitry, which samples the analog signal to provide a plurality of digital signals or samples. The timing of such sampling is in accordance with a clock signal supplied to the ADC circuitry. A phase detector is provided that detects and adjust the clock signal to have a desired phase based on frequency domain data that is output from a Fast Fourier transform (FFT) circuit that receives the digital samples. Preferably, the phase detector circuit is configured such that it need not receive all the frequency domain data output from the FFT at any given time in order to determine the clock phase. Rather, a subset of such data is supplied to the phase detector circuit, such that the phase detector has a simpler design, operates faster, and is computationally efficient. | 04-12-2012 |
20120128376 | PMD-insensitive method of chromatic dispersion estimation for a coherent receiver - Consistent with the present disclosure, a method and system for estimating chromatic dispersion of an optical signal in a coherent receiver is provided that is insensitive to polarization mode dispersion (PMD) and other polarization effects in the optical communication system. The effects of chromatic dispersion in the optical system are estimated by first calculating a phase shift between a pair of related frequency domain data outputs of a Fourier transform circuit. The calculated phase shift includes a linear phase component that is proportional to the chromatic dispersion, a DC constant phase component, and a data spectrum component. The calculated phase shift is then averaged over a number of clock cycles to remove the data spectrum components. The time averaged result is used to normalize any effects of PMD from the received signal. A slope of the linear phase component as a function of frequency is then calculated and used to estimate the value for chromatic dispersion. The chromatic dispersion estimate is then used to determine a number of coefficients of an inverse frequency response of the chromatic dispersion in the system, and is used to compensate for the chromatic dispersion. | 05-24-2012 |
20120219302 | PMD AND CHROMATIC DISPERSION TOLERANT CLOCK RECOVERY - Consistent with the present disclosure, a method and system for detecting a clock phase of an optical signal in a coherent receiver is provided that is insensitive to polarization mode dispersion (PMD) and other polarization effects in the optical communication system. The clock phase of the received signal is estimated by first calculating a phase shift between a pair of related frequency domain data outputs of a Fourier transform circuit. The calculated phase shift includes a phase component and a data spectrum component. The calculated phase shift is then averaged over a number of clock cycles to remove the data spectrum components thus enabling extraction of the phase component. A determinant function on the time averaged result is used to normalize any effects of PMD from the received signal and isolate the phase component. In this manner, the phase component is not dependent on the PMD effects in the optical communication system. The imaginary part of the phase component is then calculated to estimate the clock phase error which is used to tune an oscillator in the receiver to synchronize a sampling phase in the receiver with the received signal. An estimated value for the chromatic dispersion is determined from a resultant value of the determinant function and used to compensate for the effects of chromatic dispersion from the clock phase error estimate. | 08-30-2012 |
20120251120 | Multiplexer and Modulation Arrangements for Multi-Carrier Optical Modems - Consistent with the present disclosure, data, in digital form, is received by a transmit node of an optical communication system, and converted to an analog signal by a digital-to-analog converter (DAC) to drive a modulator. The modulator, in turn, modulates light at one of a plurality of wavelengths in accordance with the received data forming a plurality of corresponding carriers. The carriers are modulated according to one of a plurality of modulation formats and then optically combined to form a superchannel of a constant maximum capacity, for example. Accordingly, the number of carriers and the bit rate for each carrier remain constant for each modulation format to realize a constant maximum capacity. The superchannel is then transmitted over an optical communication path to a receive node. At the receive node, the superchannel is optically demultiplexed from a plurality of other superchannels. The plurality of carriers of the superchannel are then supplied to a photodetector circuit, which receives additional light at one of the optical signal carrier wavelengths from a local oscillator laser. An analog-to-digital converter (ADC) is provided in the receive node to convert the electrical signals output from the photodetector into digital form. The output from the ADC is then filtered in the electrical domain, such that optical demultiplexing of the carriers is unnecessary. | 10-04-2012 |
20130007516 | ADAPTIVE VOLTAGE SCALING BASED ON THE RESULTS OF FORWARD ERROR CORRECTION PROCESSING - In one implementation, a device may include a voltage regulator circuit, a data processing circuit, and an error correction circuit, where the error correction circuit may correct errors in data processed by the data processing circuit to obtain error-corrected data and output an error-corrected version of the processed data. Additionally, an error monitor circuit may output an error signal indicative of a level of the errors in the processed data. A control circuit may receive the error signal and control the voltage regulator circuit to adjust, based on the error signal, the supply voltage to the data processing circuit. In some implementations, the control circuit may also base its decision to control the voltage regulator circuit based on available timing margins in the data processing circuit. | 01-03-2013 |
20130022147 | COHERENT DETECTION USING COHERENT DECODING AND INTERLEAVING - A system is configured to receive a block of symbols, associated with a phase-modulated signal that includes data symbols that correspond to a payload associated with the signal, and control symbols; process the control symbols to identify an amount of phase noise associated with the control symbols; reset a phase, associated with each of the data symbols, based on the amount of phase noise and a reference phase; interleave the respective data samples, of each of the data symbols with other data samples, where the interleaved respective data samples cause errors, associated with the respective data samples, to be spread out among the other data samples and reduces an error rate relative to a prior data rate that existed before the interleaving; and perform forward error correction on the interleaved respective data samples. | 01-24-2013 |
20130173984 | FORWARD ERROR CORRECTION (FEC) CONVERGENCE BY CONTROLLING RELIABILITY LEVELS OF DECODED WORDS IN A SOFT FEC DECODER - A system receives a first word on which to perform error correction; identifies combinations in which encoded bits, within the first word, can be inverted; generates candidate words based on the first word and the combinations; decodes the candidate words; determines distances between the decoded words and the first word; selects, as a second word, one of the decoded words associated with a shortest distance; compares the second word to the first word to identify errors within the first word; generates a value to cause a reliability level of the first word to increase when a quantity of the errors is less than a threshold; generates another value to cause a reliability level of the first word to decrease when the quantity of the errors is not less than the threshold; and outputs a third word based on the first word, and the value or the other value. | 07-04-2013 |
20130259492 | REDUCING PROCESSING BIAS IN A SOFT FORWARD ERROR CORRECTION (FEC) DECODER - A system is configured to receive a word that includes a group of samples; randomly select a subset of the samples; identify first samples, from the subset, with a lowest level of reliability; select another subset of the samples; identify second samples, from the other subset, with a lowest level of reliability; and create a merged subset based on selected first samples and selected second samples. The system is also configured to select a further subset of the samples; identify third samples, from the further subset, with a lowest level of reliability; identify fourth samples, from the merged subset, associated with a lowest level of reliability; create another merged subset based on a greater probability that fourth samples than third samples are included in the other merged subset; and generate another word based a sample from the other merged subset; and process the word using the other word. | 10-03-2013 |
20140003814 | PROCESSING THREE-QUADRATURE AMPLITUDE MODULATION (3QAM) TRAFFIC USING A FOUR-BIT PHASE MODULATION SCHEME | 01-02-2014 |
20140003824 | EQUALIZATION MECHANISM FOR PROCESSING TRAFFIC BASED ON THREE-QUADRATURE AMPLITUDE MODULATION (3QAM) | 01-02-2014 |
20140178065 | NONLINEARITY COMPENSATION USING PILOT TONES - An optical system may have an optical transmitter including a digital signal processor to receive a signal channel, add data corresponding to a pilot tone, generate a digital signal associated with the signal channel and including the pilot tone, and output the digital signal. The optical system may further have a digital-to-analog converter to convert the digital signal to an analog signal, a laser to provide an optical signal, and a modulator to receive the optical signal and the analog signal, and modulate the optical signal based on the analog signal to form a modulated optical signal. The modulated optical signal may include the pilot tone. The optical system may also have an optical receiver to receive the modulated optical signal, process the modulated optical signal to determine a phase associated with the pilot tone, and apply the phase to the modulated optical signal to recover the signal channel. | 06-26-2014 |
Patent application number | Description | Published |
20120295897 | SPIRO-OXINDOLE COMPOUNDS AND THEIR USES AS THERAPEUTIC AGENTS - This invention is directed to spiro-oxindole compounds, as stereoisomers, enantiomers, tautomers thereof or mixtures thereof; or pharmaceutically acceptable salts, solvates or prodrugs thereof, for the treatment and/or prevention of sodium channel-mediated diseases or conditions, such as pain. | 11-22-2012 |
20130210801 | 2-QUINOLINYL-ACETIC ACID DERIVATIVES AS HIV ANTIVIRAL COMPOUNDS - The invention provides compounds of formula (I): or a salt thereof as described herein. The invention also provides pharmaceutical compositions comprising a compound of formula (I), processes for preparing compounds of formula (I), intermediates useful for preparing compounds of formula I and therapeutic methods for treating the proliferation of the HIV virus, treating AIDS or delaying the onset of AIDS or ARC symptoms in a mammal using compounds of formula (I). | 08-15-2013 |
20130252962 | SPIRO-OXINDOLE COMPOUNDS AND THEIR USE AS THERAPEUTIC AGENTS - This invention is directed to spiro-oxindole compounds, as stereoisomers, enantiomers, tautomers thereof or mixtures thereof; or pharmaceutically acceptable salts, solvates or prodrugs thereof, for the treatment and/or prevention of sodium channel-mediated diseases or conditions, such as pain. | 09-26-2013 |
20130274254 | INHIBITORS OF CYTOCHROME P450 (CYP3A4) - The present application provides for a compound of formula I, and related compounds, or a pharmaceutically acceptable salt, solvate, and/or ester thereof, compositions containing such compounds, therapeutic methods that include the administration of such compounds, and therapeutic methods that include the administration of such compounds with at least one additional therapeutic agent. | 10-17-2013 |
20130309197 | INHIBITORS OF CYTOCHROME P450 - The present application provides for a compound of formula I, or a salt thereof, compositions containing such compounds, therapeutic methods that include the administration of such compounds, and therapeutic methods that include the administration of such compounds with at least one additional therapeutic agent. | 11-21-2013 |
20150218147 | GLYCOSIDASE INHIBITORS AND USES THEREOF - The invention provides compounds for inhibiting glycosidases, prodrugs of the compounds, and pharmaceutical compositions including the compounds or prodrugs of the compounds. The invention also provides methods of treating diseases and disorders related to deficiency or overexpression of O-GlcNAcase, accumulation or deficiency of O-GlcNAc. | 08-06-2015 |
20150274656 | GLYCOSIDASE INHIBITORS AND USES THEREOF - The invention provides compounds for inhibiting glycosidases, prodrugs of the compounds, and pharmaceutical compositions including the compounds or prodrugs of the compounds. The invention also provides methods of treating diseases and disorders related to deficiency or overexpression of O-GlcNAcase, accumulation or deficiency of O-GlcNAc. | 10-01-2015 |
20150291623 | SPIRO-OXINDOLE COMPOUNDS AND THEIR USE AS THERAPEUTIC AGENTS - This invention is directed to spiro-oxindole compounds, as stereoisomers, enantiomers, tautomers thereof or mixtures thereof; or pharmaceutically acceptable salts, solvates or prodrugs thereof, for the treatment and/or prevention of sodium channel-mediated diseases or conditions, such as pain. | 10-15-2015 |
Patent application number | Description | Published |
20080288458 | Session Initiation Protocol (Sip) Multicast Management Method - Described are a method and system for obtaining real-time media content over an Internet Protocol network. A proxy server receives a message from a client device requesting that communications be established with a media server for obtaining a stream of media content. The proxy server sends the client device a redirection message in reply to the client device if the requested media content is available from a local replication point. The redirection message instructs the client device to communicate with the local replication point to obtain the stream of media content. | 11-20-2008 |
20110038284 | SYSTEM AND METHOD FOR WIRELESS RELAY FRAME STRUCTURE, PROTOCOL, AND OPERATION - A relay station is provided for use in a wireless communication system. The wireless communication system includes a plurality of base stations communicatively coupled to a backhaul network and at least one mobile station. The relay station is shared by at least a first base station and a second base station. The relay station includes a transceiver, a controller and relay circuitry. The transceiver transmits signals to and receives signals both base stations and a mobile station. Signals transmitted to the base stations include a single preamble, MAP and FCH. The controller is electrically connected to the transceiver and is operable to measure a signal quality of the mobile station while connected to the first base station. The relay circuitry is electrically connected to the controller and is operable to conduct a phased handoff from the first base station to the second base station based on the signal quality. | 02-17-2011 |
20110038349 | Multiple Simultaneous Wireless Connections In A Wireless Local Area Network - Multiple simultaneous associations with Wireless Access Points (WAPs) may be formed by a given wireless client to enable handoffs between the WAPs to be accelerated and, optionally, to enable both WAPs to provide simultaneous wireless services to the wireless client. Upon forming a primary association with one WAP the wireless client scans for beacon signals from other WAPs. Upon detecting another WAP, the wireless client transmits a Request To Send (RTS) message to the new WAP indicating the identity of the primary WAP. The wireless client may also identify the new WAP to the primary WAP using a RTS message. The primary and secondary WAPs exchange information so that, in the event of a handoff, the required information has already been shared with the new WAP. Optionally, the several WAPs may provide simultaneous service to the wireless client. | 02-17-2011 |
20110126016 | SYSTEM AND METHOD FOR SECURE WIRELESS MULTI-HOP NETWORK FORMATION - The present invention provides methods and devices for a security architecture for use in wireless multi-hop networks. A method for implementing pair-wise encryption key establishment, network node authentication and determining tunnel encryption keys is provided in a following manner. In a multi-hop wireless network including a plurality of network nodes, pair-wise security is established between pairs of neighbouring network nodes of the plurality of network nodes. For example, pair-wise security is established in the form of temporal pair-wise encryption keys. Following establishment of pair-wise security between pairs of neighbouring network nodes, for a pair of network nodes that are not neighbours, tunnel security is established between the pair of network nodes using tunnel encryption keys derived by the pair of network nodes on an ad hoc basis. The tunnel encryption keys are used to form the connection between non-neighbouring network nodes so as to avoid the hop-by-hop encryption/decryption used in conventional multi-hop wireless systems. | 05-26-2011 |
20110293093 | METHOD AND SYSTEM FOR IDENTITY-BASED KEY MANAGEMENT - Systems, methods and devices for distributing a group key between a transmitter and a group of receivers connected over a network. The described group key distribution can be implemented in any television network for encrypted transmission of television related content to large and dynamic groups of subscribers' receivers. Wherein each receiver contributes to the group key by securely transmitting its contribution to the transmitter. The transmitter also contributes to the group key and generates the group key based on all contributions. The transmitter further generates partial keys specific to each receiver such that each receiver can generate a copy of the group key from its contribution and the partial key it receives. The transmitter sends each receiver its corresponding partial key so that each receiver can calculate a copy of the group key. | 12-01-2011 |
20130148644 | System and Method for Preambles in a Wireless Communications Network - A method for transmitting a frame includes generating an omni portion of the frame, the omni portion including a non-beamformed long training field and a signal field, the non-beamformed long training field including channel estimation information used to decode the signal field, the non-beamformed long training field configured to be transmitted through one of multiple antennas and multiple streams. The method also includes generating a multi-stream portion of the frame, the multi-stream portion including a data field and a multi-stream long training field, the multi-stream long training field including station-specific decoding information for station-specific data in the data field. The method further includes applying a beamforming indicator to the signal field of the omni portion, and transmitting the frame. | 06-13-2013 |
20130177002 | Systems and Methods for AP Discovery with FILS Beacon - A method and apparatus are disclosed for supporting access point (AP) discovery by a handset/station (STA) using a fast initial link setup (FILS) discovery frame. An embodiment method includes transmitting a plurality of FILS discovery frames at faster time intervals than designated for transmitting standard AP beacons, wherein the FILS discovery frames have a smaller size than standard AP beacons. An embodiment apparatus includes a processor and a computer readable storage medium storing programming for execution by the processor, the programming including instructions to broadcast a standard AP beacon for advertising a basic service set (BSS) repeatedly at subsequent time intervals, and broadcast a FILS discovery frame for advertising the BSS repeatedly at faster subsequent time intervals than for the standard AP beacon, wherein the FILS discovery frame has a smaller size than the standard AP beacon. | 07-11-2013 |
20130179943 | Systems and Methods for Authentication - A method of performing authentication involves receiving, by a station, an initiation frame and transmitting, by the station, an authentication request. The authentication request includes an extensible authentication protocol (EAP) over local area network (LAN) (EAPOL) Start and security parameters for a fast initial link setup (FILS) handshake. | 07-11-2013 |
20130235859 | 802.11 PHY HASHED SSID - An access point (AP) hashes its SSID/BSSID according to a hashing function H and transmits wirelessly the hashed SSID/BSSID within a physical layer frame/packet to a user station (STA). The hashed SSID/BSSID uniquely identifies the AP. In one embodiment, the hashed SSID/BSSID is transmitted within a SIGNAL field of a preamble with the frame/packet. Upon receipt, the user station recovers the hashed SSID/BSSID and compares it to an expected hashed SSID/BSSID (calculated using the same hashing function H and a desired SSID/BSSID). In response to the comparison, the user station performs one or more actions. | 09-12-2013 |
20130283346 | System and Method For Rapid Authentication In Wireless Communications - Various methods and communications devices to improve association and handoff performance of a wireless network are provided. By way of example, a modified state machine that permits reduced security requirements for authentication in order to achieve fast authentication is employed. The modified state machine providing fast authentication remains compatible with the classic state machine implementing the wireless fidelity (WiFi) standard. | 10-24-2013 |
20130308447 | Systems and Methods to Provision Quality of Service Sensitive Devices in Wireless Local Area Networks - System and method embodiments are provided for provisioning a quality of cellular user experience (QoE) or quality of service (QoS) specified device in a wireless local area network (LAN). The embodiments enable a QoE or QoS specified by a service agreement for a device to be maintained during periods when the device is transmitting data to and receiving data from the wireless LAN (e.g., a WiFi hotspot). In an embodiment, a method includes determining that at least one QoS-sensitive device is communicating with a wireless LAN access point (AP), reserving a contention free period (CFP) in a superframe for the at least one QoS-sensitive device to communicate with the AP, and allocating a contention period (CP) in the superframe for non-QoS-sensitive devices to communicate with the AP, wherein the non-QoS-sensitive devices are prohibited from transmitting during the CFP. | 11-21-2013 |
20140056204 | Systems and Methods for Interference Alignment in Wi-Fi - System and method embodiments are provided for interference alignment in a wireless local area network (LAN) with an overlapping basic service set (OBSS). In an embodiment, a method includes instructing a first access point (AP) in the wireless LAN to broadcast a null data packet (NDP) sounding packet to a plurality of stations when no other AP is broadcasting, wherein the NDP sounding packet comprises a plurality of long training field (LTFs), and wherein a total number of LTFs is equal to a total number of transmission streams, receiving channel beamforming (BF) information and a signal plus interference to noise ratio (SINR) from each of the stations, wherein each of the stations computes the channel BF information and the SINR from sounding packets received from each of the APs in the wireless LAN, and determining a transmission schedule according to the SINRs and the channel BF information. | 02-27-2014 |
20140056205 | System and Method for a Collaborative Service Set - In one embodiment, a collaborative service set (CSS) includes a controller access point (AP) configured to be associated with a first plurality of stations and a first member AP, where the first member AP is associated with a second plurality of stations, where the controller AP is configured to coordinate transmissions between the first member AP and the second plurality of stations with transmissions between the controller AP and the first plurality of stations, where the controller AP and the first member AP are configured to transmit messages simultaneously. | 02-27-2014 |
20140169339 | Systems and Methods to Achieve Fairness in Wireless LANs for Cellular Offloading - System and method embodiments are included to provide various degrees of time allocation fairness to users using varying target transmission opportunity (TXOP) values. In one embodiment, a method for promoting various degrees of fairness for users in a wireless network includes assigning a target TXOP value for one or more users in the wireless network, wherein the target TXOP value indicates a number of time units for transmissions to be met on average over time by the one or more users, and transmitting the target TXOP value to the one or more users. In another embodiment, a method includes receiving a TXOP value from the wireless network, wherein the target TXOP value indicates a number of time units allocated for transmissions, and transmitting traffic over a plurality of time periods that have an average duration about equal to the number of time units. | 06-19-2014 |
20140204746 | OpenFlow Enabled WiFi Management Entity Architecture - System and method embodiments are provided to improve offloading traffic from mobile operators networks via a WiFi network. The embodiments also include schemes to offload traffic between WiFi networks. The embodiments include a network component comprising a WiFi management entity (WiME) configured to serve as an anchor point for a user device at a WiFi network and communicate with a management entity at a wireless network using OpenFlow protocol to handle a plurality of control and mobility functionalities for traffic in the WiFi network, wherein the control and mobility functionalities include offloading traffic for the user device from the wireless network to the WiFi network. | 07-24-2014 |
20140341129 | Systems and Methods for Operation of Wireless User Devices with Cellular and Wi-Fi Interfaces - An embodiment method for wireless communication includes grouping a plurality of user equipments (UEs) wirelessly coupled to a cellular base station (BS) into a UE cluster to function as a Wi-Fi virtual station (V-STA), and communicating with an access point (AP) to contend for a Wi-Fi transmission opportunity (TXOP) for the V-STA. In a further embodiment, the cellular BS contends for the TXOP on behalf of the UE cluster using a carrier sense multiple access with collision avoidance (CSMA-CA) procedure. In an alternative embodiment, one UE in the UE cluster is selected as a leader UE to contend for the TXOP on behalf of the UE cluster using a CSMA-CA procedure. | 11-20-2014 |
20140376532 | System and Method for a CSMA-CA Half Window Scheme - Embodiments are provided for implementing a CSMA-CA half window scheme in 802.11 networks or other suitable wireless networks that could benefit from such scheme. The half window scheme improves a back-off time calculation by adding a probability prediction factor. The back-off time is part of a delay time in accessing a wireless transmission medium by a station (STA). The probability prediction factor is used to adjust a contention widow (CW) used to calculate the back-off time, based on the STA's medium access probability. The STA splits the CW into two at least half windows and then chooses one of the windows according to the window's information gain for the probability prediction. The selected window is used to select a random number for the back-off time. The improved back-off time calculation reduces contention between STAs in accessing the medium. | 12-25-2014 |
20150131756 | System and Method for High Efficiency Wireless Local Area Network Communications - System and method embodiments are provided for high efficiency wireless communications. In an embodiment, a method in a network component for transmitting a frame of two different fast Fourier transform (FFT) sizes includes generating a frame, wherein the frame comprises orthogonal frequency-division multiplexing (OFDM) symbols in two different FFT sizes, wherein the frame comprises a first portion and a second portion, wherein the first portion comprises a first FFT size and the second portion comprises a second FFT size; and transmitting the frame during a single transmission opportunity. | 05-14-2015 |
20150215818 | Dual-Stream Signal (SIG) Field Encoding with Higher Order Modulation - Signal (SIF) field capacity can be significantly increased by encoding SIG field data using two streams in accordance with a space-time block code (STBC) encoding scheme. Dual-stream SIG field encoding allows for the utilization of higher order modulation schemes, such as quadrature phase-shift keying (QPSK), which increases SIG field capacity. Dual-stream encoded SIG fields are transmitted using an omnidirectional beam to allow mobile stations to accurately decode the SIG field irrespective of their spatial location. | 07-30-2015 |
20150271668 | FAST AUTHENTICATION FOR INTER-DOMAIN HANDOVERS - Fast mobile device authentication can be achieved during inter-domain handovers between administrative domains operating under a federated service agreement using pseudonym identifications (PID). Specifically, the mobile device may derive a PID when obtaining authentication in a first wireless network, and then use the PID to obtain fast authentication in a second wireless network. The PID may be generated during an Elliptic curve Diffie-Hellman (ECDH) authentication procedure using public keys associated with the mobile device and the first wireless network. The PID (or a derivative thereof) may then be provided to an authentication server in a second wireless network for validation. The PID may be validated by the second authentication server via online or offline validation procedures. The PID can also be used as an electronic coupon for accessing the second network. | 09-24-2015 |
20150271704 | System and Method for Preambles in a Wireless Communications Network - A method for transmitting a frame includes generating an omni portion of the frame, the omni portion including a non-beamformed long training field and a signal field, the non-beamformed long training field including channel estimation information used to decode the signal field, the non-beamformed long training field configured to be transmitted through one of multiple antennas and multiple streams. The method also includes generating a multi-stream portion of the frame, the multi-stream portion including a data field and a multi-stream long training field, the multi-stream long training field including station-specific decoding information for station-specific data in the data field. The method further includes applying a beamforming indicator to the signal field of the omni portion, and transmitting the frame. | 09-24-2015 |
20150281962 | Systems and Methods for Authentication - A method includes transmitting, by a station to an access point (AP), a fast initial link setup (FILS) authentication request and transmitting, by the station to the AP, an authorization request, where the authorization request includes an extensible authentication protocol (EAP) over local area network (LAN) (EAPOL) key. The method also includes receiving, by the station from the AP, an association response, where the association response includes the EAPOL key. | 10-01-2015 |
20150327217 | System and Method for Orthogonal Frequency Division Multiple Access Communications - A method for operating a communications device adapted for orthogonal frequency division multiple access (OFDMA) wireless local area network (WLAN) communications includes generating an OFDMA preamble comprising an OFDMA signal (SIG) field including an indication of an allocation of an OFDMA resource to a station, and transmitting the OFDMA preamble in a frame. | 11-12-2015 |
20160029432 | Pause Signals for Full-Duplex Wireless Networks - System and method embodiments are provided for pausing data transmission in a full-duplex wireless network. Embodiments eliminate the deadlocks in the full duplex MAC layer and improve the system efficiency. In an embodiment, a method in a wirelessly enabled and full duplex enabled network component for pausing an ongoing data transmission includes beginning a transmission, with the network component, of first data to a first station; determining, with the network component, that transmission of a second data to a second station is required before completion of the transmission of the first data to the first station; transmitting, with the network component, a pause indicator to the first station notifying the first station that transmission of the first data will be paused; transmitting, with the network component, the second data to the second station; and resuming transmitting, with the network component, the first data to the first station. | 01-28-2016 |
20160066313 | System and Method for Cumulative Beacons - A method for operating a first access point of a first plurality of access points comprising access points participating in cumulative beacon operations includes generating a cumulative beacon including basic service set identifiers (BSSIDs) and service set identifiers (SSIDs) of each access point in the first plurality of access points, and sending the cumulative beacon. | 03-03-2016 |
20160088637 | Systems and Methods for Interference Alignment in Wi-Fi - System and method embodiments are provided for interference alignment in a wireless local area network (LAN) with an overlapping basic service set (OBSS). In an embodiment, a method includes instructing a first access point (AP) in the wireless LAN to broadcast a null data packet (NDP) sounding packet to a plurality of stations when no other AP is broadcasting, wherein the NDP sounding packet comprises a plurality of long training field (LTFs), and wherein a total number of LTFs is equal to a total number of transmission streams, receiving channel beamforming (BF) information and a signal plus interference to noise ratio (SINR) from each of the stations, wherein each of the stations computes the channel BF information and the SINR from sounding packets received from each of the APs in the wireless LAN, and determining a transmission schedule according to the SINRs and the channel BF information. | 03-24-2016 |
20160088657 | Virtual Busy-Tone for Full-Duplex Wireless Networks - System and method embodiments are provided for a virtual busy-tone for full-duplex wireless networks. Embodiments provide a mechanism for efficiently eliminating the hidden node problem. In an embodiment, a method in a full-duplex enabled wireless network component for avoiding collisions includes receiving, at the network component, a data transmission from a first station; and transmitting a busy indicator from the network component, the busy indicator including a time duration determined in accordance with an expected time duration of the data transmission to instruct any non-transmitting station to not transmit data during the included time duration. | 03-24-2016 |
20160094992 | System and Method for Rapid Authentication in Wireless Communications - Various methods and communications devices to improve association and handoff performance of a wireless network are provided. By way of example, a modified state machine that permits reduced security requirements for authentication in order to achieve fast authentication is employed. The modified state machine providing fast authentication remains compatible with the classic state machine implementing the wireless fidelity (WiFi) standard. | 03-31-2016 |
Patent application number | Description | Published |
20080292789 | ONE-DIMENSIONAL METAL AND METAL OXIDE NANOSTRUCTURES - Metal powder (such as tin, titanium, or tungsten powder) is heated in a flowing stream of an inert gas, such as argon, containing a small abundance of oxygen at a temperature to produce metal vapor. The metal reacts with the oxygen to form and deposit one-dimensional nanostructures of oxygen-containing metal on the metal powder (in the case of Ti and W) or on a suitable nearby substrate in the case of the lower melting tin. The metal oxides are not necessarily stoichiometric compounds. Water may be introduced into the flowing inert gas to increase or control the oxygen content. Sulfur vapor or a carbon source may be introduced to dope the nanostructures with sulfur or carbon. Reaction conditions may be modified to vary the shapes of the one-dimensional nanostructures. | 11-27-2008 |
20090004552 | NANOWIRE SUPPORTED CATALYSTS FOR FUEL CELL ELECTRODES - Metal oxide nanowires and carbon-coated metal nanowires are effective as supports for particles of an expensive catalyst material, such as platinum metal group catalyst. Such supported catalysts are useful when included in an electrode on, for example, a proton exchange membrane in a hydrogen/oxygen fuel cell. For example, tin oxide nanowires are formed on carbon fibers of carbon paper and platinum nanoparticles are deposited on the tin oxide nanowires. The nanowires provide good surfaces for effective utilization of the platinum material. | 01-01-2009 |
20100130351 | SYNTHESIS OF RARE EARTH ELEMENT-CONTAINING ALUMINA NANOWIRES - Rare earth element(s) doped alumina nanowires are formed by a thermal evaporation method in which vapor from aluminum powder and vapor from a rare earth element compound (such as an halide) are reacted in an oxygen-containing inert gas stream to form alumina which deposits as alumina nanowires and as a rare earth element and oxygen-containing material that deposits with and/or on the alumina nanowires. Where the RE-doped alumina nanowires are to be used as catalyst supports, a catalyst material, such as platinum, may be deposited as small particles on the nanowires. | 05-27-2010 |
20100316873 | ONE-DIMENSIONAL METAL NANOSTRUCTURES - Tin powder is heated in a flowing stream of an inert gas, such as argon, containing a small concentration of carbon-containing gas, at a temperature to produce metal vapor. The tin deposits as liquid on a substrate, and reacts with the carbon-containing gas to form carbon nanotubes in the liquid tin. Upon cooling and solidification, a composite of tin nanowires bearing coatings of carbon nanotubes is formed. | 12-16-2010 |
20110197710 | Making metal and bimetal nanostructures with controlled morphology - A method of making metal nanostructures having a nanometer size in at least one dimension includes preparing an aqueous solution comprising a cation of a first metal and an anion, and mixing commercial elemental powder particles of an elemental second metal having a greater reduction potential than the first metal with the aqueous solution in an amount that reacts and dissolves all of the second metal and precipitates the first metal as metal nanostructures. The temperature and concentration of the aqueous solution and the selection of the anions and the second metal are chosen to produce metal nanostructures of a desired shape, for example ribbons, wires, flowers, rods, spheres, hollow spheres, scrolls, tubes, sheets, hexagonal sheets, rice, cones, dendrites, or particles. | 08-18-2011 |
20120003563 | POROUS DENDRITIC PLATINUM TUBES AS FUEL CELL ELECTROCATALYSTS - Platinum particles have been formed as porous, hollow tubular dendrites by using silver dendrite particles in a galvanic replacement reaction conducted in an aqueous solution of a platinum compound. The dendritic platinum particles have been found useful as catalysts and particularly useful as a hydrogen-oxidation electrocatalyst and/or an oxygen-reduction catalyst in a polymer electrolyte membrane fuel cell. | 01-05-2012 |
20120177995 | Secondary Lithium Batteries Having Novel Anodes - A secondary lithium battery having an anode comprising graphene nanosheets doped with a doping element selected from the group consisting of nitrogen, boron, sulfur, phosphorous and combinations thereof. The secondary lithium battery and the anode provide capacity and other performance without degradation during long term charge and discharge cycling. | 07-12-2012 |
20120241192 | MICROFIBER SUPPORTED METAL SILICIDE NANOWIRES - An arrangement of elongated nanowires that include titanium silicide or tungsten silicide may be grown on the exterior surfaces of many individual electrically conductive microfibers of much larger diameter. Each of the nanowires is structurally defined by an elongated, centralized titanium silicide or tungsten silicide nanocore that terminates in a distally spaced gold particle and which is co-axially surrounded by a removable amorphous nanoshell. A gold-directed catalytic growth mechanism initiated during a low pressure chemical vapor deposition process is used to grow the nanowires uniformly along the entire length and circumference of the electrically conductive microfibers where growth is intended. The titanium silicide- or tungsten silicide-based nanowires can be used in a variety electrical, electrochemical, and semiconductor applications. | 09-27-2012 |
20120308818 | ONE-DIMENSIONAL METAL NANOSTRUCTURES - Tin powder is heated in a flowing stream of an inert gas, such as argon, containing a small concentration of carbon-containing gas, at a temperature to produce metal vapor. The tin deposits as liquid on a substrate, and reacts with the carbon-containing gas to form carbon nanotubes in the liquid tin. Upon cooling and solidification, a composite of tin nanowires bearing coatings of carbon nanotubes is formed. | 12-06-2012 |
20140199546 | MULTI-BRANCHED N-DOPED CARBON NANOTUBES AND THE PROCESS FOR MAKING SAME - A multibranched N-doped carbon nanotube (CNT) and the process of production are described. The CNT includes a first-stage stalk having a direction comprising a first-stage base, and a first-stage top opposite to and attached with the first-stage base, at least two second-stage bundles, each of which comprises a second-stage base attached to the first-stage top, and second-stage top opposite to and attached with the second-stage base, and wherein the second-stage bundles branch from the first-stage stalk in substantially the direction of the first stage stalk, and a plurality of third-stage nanotubes each of which comprises a third-stage base attached to the second-stage top, a third-stage top opposite to and attached with the third-stage base, and wherein the plurality of third-stage nanotubes branch from the second-stage bundles. | 07-17-2014 |
20150099173 | METHOD FOR MASS PRODUCTION OF SILICON NANOWIRES AND/OR NANOBELTS, AND LITHIUM BATTERIES AND ANODES USING THE SILICON NANOWIRES AND/OR NANOBELTS - This invention provides a method for mass production of silicon nanowires and/or nanobelts. The invented method is a chemical etching process employing an etchant that preferentially etches and removes other phases from a multiphase silicon alloy, over a silicon phase, and allows harvesting of the residual silicon nanowires and/or nanobelts. The silicon alloy comprises, or is treated so as to comprise, one-dimensional and/or two-dimensional silicon nanostructures in the microstructure of the multi-phase silicon alloy prior to etching. When used as anode for secondary lithium batteries, the silicon nanowires or nanobelts produced by the invented method exhibit high storage capacity. | 04-09-2015 |