| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 398076000 | Subcarrier multiplexing | 52 |
| 20080292315 | Anti Clipping Circuit For Laser Transmitters - This anti clipping circuit is for a laser transmitter used to transmit sub-carrier multiplexed signals for CATV applications. The circuit design is based on actual clipping measurements showing the specific time and duration of the clipping events is random. The individual clipping pulses interval is fixed, every 4 us. A PHEMT peak detection circuit is used in conjunction with a missing pulse detector/timer to catch all the clipping events. Thus the laser bias current is adjusted automatically at the specific time of the clipping event and for the duration of all the clipping pulses in the event. The controlled increase and decrease of the lasers bias current is DC coupled back into the normal DC bias path via a diode. This gives the anti clipping circuit noise isolation when there are no clipping events and avoids laser clipping during the laser current recovery time as when using an AC coupling scheme. | 11-27-2008 |
| 20090154927 | MULTI-CARRIER COMMUNICATION VIA SUB-CARRIER GROUPS - One embodiment of the present invention relates to a method for communicating over a multi-carrier communication channel. In the method, sub-carrier frequencies that are reserved for communication between a pair of nework nodes are associated with different sub-carrier groups, where the sub-carriers of each sub-carrier group are assigned a common transmission characteristic that is independent of the transmission characteric for the other sub-carrier groups. Other methods and devices are also disclosed. | 06-18-2009 |
| 20090202245 | System and Method for Increasing Upstream Capacity in an Optical Network - A method for communicating in a passive optical network (PON), includes receiving traffic from a plurality of optical network units (ONUs) transmitting in an upstream transmission channel, wherein each of the ONUs may transmit at any wavelength within a wavelength band associated with the upstream transmission channel. The method also includes dividing the upstream transmission channel into a plurality of sub-channels, that each include a subset of the wavelength band associated with the upstream transmission channel. The method further includes determining the identity of each of the plurality of ONUs transmitting in each of the sub-channels, assigning a plurality of ONUs transmitting in the upstream transmission channel to each of at least two of the sub-channels based on the determination of the ONUs transmitting in that sub-channel, and allocating transmission timeslots for time-shared transmission by the ONUs in one or more of the sub-channels. | 08-13-2009 |
| 20090324226 | System, method and apparatus for channel estimation based on intra-symbol frequency domain averaging for coherent optical OFDM - System, apparatus and method of optical communication are provided for performing efficient channel estimation for a CO-OFDM link utilizing an intra-symbol frequency-domain averaging (ISFA) to compensate for transmission impairments. An exemplary method includes receiving a pair of training symbols in an optical orthogonal frequency-division multiplexed (OFDM) signal, performing channel estimation to obtain a first estimated channel matrix for each of a plurality of subcarriers of the OFDM signal; and averaging the first estimated channel matrix of a first subcarrier with the first estimated channel matrix of others of the subcarriers to obtain a second estimated channel matrix for the first subcarrier. The second estimated channel matrix may be an average or weighted average. Prior to the averaging, compensation of chromatic dispersion may be performed. Channel compensation is performed based on the second estimated channel matrix for the first subcarrier of the OFDM signal and symbols then decoded. | 12-31-2009 |
| 20100080560 | OFDM DIRECT DETECTION USING A BALANCED RECEIVER - A receiver for demodulating optical OFDM signals may detect an optical OFDM signal that includes a carrier and data subcarriers by optically splitting the carrier from the subcarriers using a frequency selective filter and then recombining the carrier and the subcarriers using an optical coupler and balanced detector. | 04-01-2010 |
| 20100086305 | REDUCING CROSS-MODULATION IN MULTICHANNEL MODULATED OPTICAL SYSTEMS - A modulated optical system with cross-modulation compensation reduces or corrects cross-modulation that might occur in a multichannel RF signal modulating a laser. The system detects the cross-modulation, for example, by detecting an envelope of the RF signal or by detecting RF power fluctuations, generates a cross-modulation detection signal, and imparts a compensating cross-modulation by adjusting a bias current of the laser in response to the cross-modulation detection signal. | 04-08-2010 |
| 20100098421 | Optical interface method and apparatus - An optical interface method includes producing a digital wrapper signal by synchronizing a client signal that is inputted via an optical transmission channel with an oscillating frequency of a fixed oscillator; returning the digital wrapper signal back into the client signal; and outputting the client signal obtained from the digital wrapper signal by the returning onto the optical transmission channel. The oscillating frequency of the fixed oscillator is set higher than a frequency of the client signal in the optical transmission channel. | 04-22-2010 |
| 20100202775 | METHOD, APPARATUS AND SYSTEM FOR HIGH-SPEED TRANSMISSION ON FIBER OPTIC CHANNEL - Multi-carrier modulation fiber optic systems constructed using a series of electrical carriers, modulating the data on the electrical carriers and combining the carriers to form a wideband signal. The wideband signal can then be intensity modulated on a laser and coupled to a fiber optic channel. A receiver may then receive the laser signal from the fiber optic channel and convert it into an electrical signal. Multi-carrier modulation may be applied to existing fiber channels, which may be of lower quality. Existing fiber channels may have characteristics which prevent or restrict the transmission of data using intensity modulation at certain frequencies. An adaptive multi-carrier modulation transmitter may characterize an existing fiber optic channel and ascertain the overall characteristics of the channel. The transmitter and receiver can then be configured to use various bandwidths and various modulations in order to match the transfer characteristic of the fiber channel. A series of adaptive multi-carrier modulation transmitters and receivers can be integrated on a single integrated circuit. If multiple adaptive receivers and transmitters are integrated on a single integrated circuit, they may be used to upgrade existing networks by adding different wavelength lasers for the transmission of data in order to achieve any capacity desired. Each receiver and transmitter may characterize the fiber for its particular wavelength laser and may configure the modulation and bandpass to the fiber's characteristics. | 08-12-2010 |
| 20110206376 | METHOD FOR DATA PROCESSING IN AN OPTICAL NETWORK, OPTICAL NETWORK COMPONENT AND COMMUNICATION SYSTEM - A method for data processing in an optical network includes providing at least one main wavelength and processing a subcarrier modulation for the at least one main wavelength, wherein a portion of the subcarrier modulated signal is suppressed. An optical network component and a communication system having such an optical network component are also provided. | 08-25-2011 |
| 20120057872 | BLIND TIMING SYNCHRONIZATION AND LOW COMPLEXITY CHANNEL ESTIMATION IN ACO-OFDM SYSTEMS - A wireless transmit/receive unit (WTRU) that may receive an asymmetrically clipped optical orthogonal frequency-division multiplexing (ACO-OFDM) signal is disclosed. The ACO-OFDM signal may include an ACO-OFDM symbol and the ACO-OFDM signal may be generated with or without a pilot or training data. Where the ACO-OFDM signal may not include a pilot or training data, the WTRU may determine a correlation minimum between a first part of N samples of the ACO-OFDM symbol and a second part of N samples of the ACO-OFDM symbol. The correlation minimum may indicate an estimated boundary of the ACO-OFDM symbol which may provide the WTRU with timing synchronization information. Where the ACO-OFDM signal may include one or more ACO-OFDM pilot symbols on one or more pilot subcarriers, the WTRU may interpret an amount of training data included in the one or more ACO-OFDM pilot symbols that may provide information for channel estimation. | 03-08-2012 |
| 20120121266 | RECEIVER, LIGHT SPECTRUM SHAPING METHOD, AND OPTICAL COMMUNICATION SYSTEM - A receiver receiving a phase-modulated optical frequency division multiplexed signal is provided. The receiver includes a light spectrum shaper configured to extract a carrier wave and a modulated light component contained in either one of a short-wavelength-side waveband or a long-wavelength-side waveband with respect to the carrier wave, to output a spectrum-shaped light signal; and an optical-to-electric converter configured to convert the spectrum-shaped light signal into an electric signal. | 05-17-2012 |
| 20120170937 | VARIABLE CHANNEL SPACING IN A COHERENT TRANSMISSION SYSTEM - The present disclosure provides a transmission system, apparatus and method to provide for variable channel spacing in multiplexed or combined optical signals for transmission over a network infrastructure. The channel spacing may be monitored and maintained at desired values in order to maximize the channel density under various conditions related to the network infrastructure. The individual carrier frequencies associated with each signal channel of the transmission system may be individually controlled to define the desired channel. The channel spacing may be altered to provide for higher channel densities increasing system capacity, or to provide for lower channel densities improving the overall reach of the transmission system. The channel spacing may be continuously monitored and maintained at desired values allowing for rapid and automated reconfiguration of the transmission system, which may result in maximized capacity and reduced costs. | 07-05-2012 |
| 20120257897 | Energy Efficient OFDM Transceiver - An energy efficient OFDM transceiver includes a transmitter using a decision processor to control first internal elements that can be operated in parallel and can be selectively powered off or hibernated, and a receiver using a processing decision element to control second internal elements that can be operated in parallel and can be selectively powered off or hibernated, wherein control of the first and second internal elements enables tracking status of network traffic, adjustment of OFDM bandwidth based on a traffic decision and selectively powering off or hibernating parallel ones of the first and second internal elements. | 10-11-2012 |
| 20120257898 | APPARATUS AND METHOD FOR TRANSMITTING DATA BY USING VISIBLE LIGHT - Disclosed is an apparatus and a method for transmitting data by using visible light. The transmission apparatus includes: a Serial-to-Parallel (S/P) converter for performing a Serial-to-Parallel conversion on transmission data, and generating multiple parallel data; a modulation means for modulating the multiple parallel data generated by the S/P converter, and generating multiple modulation signals; an Inverse Fast Fourier Transform (IFFT) means for performing an IFFT on the multiple modulation signals so that the multiple modulation signals are orthogonal to one another, and generating an IFFT signal; and a light-emitting means for causing a light source to emit light based on the IFFT signal generated by the IFFT means. | 10-11-2012 |
| 20120321318 | CARRIER AND SUBCARRIER HOPPING FOR OPTICAL OFDM SECURITY - Methods and systems for secure communication include assigning data streams to respective orthogonal sub-carriers according to random number information at a transmitter. The data streams are modulated onto the respective orthogonal sub-carriers before the orthogonal sub-carriers are transmitted. The random number information is transmitted on a second medium, separate from the transmission medium. The orthogonal sub-carriers are received from the transmission medium at a receiver, while the random number information is received from the second medium at the receiver. The orthogonal sub-carriers are associated with data streams using the random number information and demodulated to produce data for the associated data stream. | 12-20-2012 |
| 20130004173 | OVERLAY SYSTEM WITH DIGITAL OPTICAL TRANSMITTER FOR DIGITIZED NARROWCAST SIGNALS - Methods and apparatuses are provided to modify existing overlay system architectures in a cost effective manner to meet the growing demand for narrowcast services and to position the existing overlay systems for additional future modifications. The implementations of the improved overlay system of this disclosure re-digitize narrowcast analog signals after they have been QAM modulated and upconverted to RF frequencies and replace the analog narrowcast transmitters with digital narrowcast transmitters. In the fiber nodes, the received narrowcast signals are converted back to analog signals and combined with analog broadcast signals for transmission to the service groups. | 01-03-2013 |
| 20130016975 | FREQUENCY MODULATED BURST MODE TRANSMITTER - The present invention is directed towards a frequency modulated (FM) burst mode optical system that allows optical signals having a common wavelength provided by a plurality of FM burst mode optical transmitters to be passively combined onto a single optical fiber. A single FM optical receiver receives the combined signals and processes them accordingly. Each FM burst mode optical transmitter includes an FM modulator, is carrier detect circuit and a laser. The FM modulator modulates a carrier signal, such as a 1.21 GHz signal, with received reverse electrical signals. When a subcarrier signal is detected o the carrier detect circuit, the laser is turned and the frequency modulated carrier signal is used to intensity modulate a laser to provide an optical signal. Due to the burst-mode transmission of optical signals, the optical signals can be passively combined and transmitted to a single optical receiver. | 01-17-2013 |
| 20130202303 | HIGH-SPEED LOW-JITTER COMMUNICATION SYSTEM - Communication apparatus and techniques, such as for optical communication, can include providing a reference frequency derived from an atomic energy level transition or a molecular energy level transition, generating at least two specified optical carrier signals at least in part using the reference frequency, coherently modulating the specified optical carrier signals using respective baseband information signals to provide respective coherently-modulated optical subcarriers. A combined optical information signal comprising the optical subcarriers can be transmitted to a receiver, such as via a fiber optic cable. In an example, a received optical information signal can be optically Fourier transformed to provide respective coherent outputs, which can be coherently downconverted. | 08-08-2013 |
| 20130223842 | OPTICAL SIGNAL TRANSMITTING DEVICE, OPTICAL SIGNAL TRANSMITTING METHOD, FREQUENCY FLUCTUATION SUPPRESSING DEVICE AND FREQUENCY FLUCTUATION SUPPRESSING SYSTEM - An optical signal transmitting device includes direct modulators configured to be driven using electric signals of channels to generate directly-modulated optical signals of channels, a beat light source configured to generate beat light at a specific frequency spacing, subcarrier converters configured to modulate, using the beat light from the beat light source, the directly-modulated optical signals of the channels from the direct modulators to generate optical subcarrier modulation signals of channels, probe light sources configured to generate probe light of channels having frequencies that are different from frequencies of the directly-modulated optical signals of the channels, multiplexers configured to multiplex, for individual channels, the optical subcarrier modulation signals of the channels with the probe light of the channels, and nonlinear optical media configured to perform, for individual channels, optical cross modulation for the optical subcarrier modulation signals and the probe light, which are multiplexed, and transmit processed signals. | 08-29-2013 |
| 20130308949 | OPTICAL ORTHOGONAL FREQUENCY DIVISION MULTIPLE MULTIPLEXING RECEIVER AND OPTICAL SIGNAL RECEIVING METHOD THEREOF - Provided is an optical OFDM receiver. The optical OFDM receiver receives an optical signal dependent on the nonlinearity of a transmitter. The optical OFDM receives includes an optical down converter, a nonlinearity compensator, and an OFDM demodulator. The optical down converter converts the optical signal into an electrical signal. The nonlinearity compensator filters the electrical signal, for compensating distortion which is added to the optical signal when the transmitter performs optical modulation. The OFDM demodulator demodulates the distortion-compensated electrical signal in an OFDM scheme. | 11-21-2013 |
| 20140056586 | Channel Bonding for Ethernet Passive Optical Network Over coax (EPoC) Networks - Embodiments provide systems and methods for enabling the support of multiple Ethernet Passive Optical Network over Coax (EPoC) channels, which can be bonded together into a single high-speed channel. The multiple EPoC channels can be configured according to available spectrum, such that they occupy one or more, frequency contiguous or separated, segments of the available spectrum. The size (number of sub-carriers) of each of the channels can be configured according to embodiments based on the available spectrum and/or other requirements (e.g., EPoC emission requirements, existing services, etc.). Further, within each channel, individual sub-carriers can be configured independently, including turning each sub-carrier on/off and/or specifying the symbol bit loading for the sub-carrier independently of other sub-carriers in the channel. | 02-27-2014 |
| 20140064732 | APPARATUS AND METHOD FOR RECEIVING OPTICAL SIGNAL, AND OPTICAL FREQUENCY-DIVISION-MULTIPLEXING TRANSMISSION SYSTEM - An optical signal receiving apparatus includes: a chromatic dispersion medium having an amount of chromatic dispersion which is determined according to a frequency of the sub-carrier modulation signals so as to receive the sub-carrier modulation signals, a photodetector configured to convert the carrier optical signal that has passed through the chromatic dispersion medium, into electrical signals, and a signal receiving unit configured to receive an electrical signal selected from the electrical signals obtained by the photodetector. | 03-06-2014 |
| 20140079399 | Time to Time-Frequency Mapping and Demapping for Ethernet Passive Optical Network over Coax (EPoC) - Embodiments include, but are not limited to, systems and methods for enabling Orthogonal Frequency Division Multiple Access (OFDMA) in the upstream in an Ethernet Passive Optical Network over Coax (EPoC) network. Embodiments include systems and methods for translating Ethernet Passive Optical Network (EPON) upstream time grants to OFDMA resources represented by individual subcarriers of an upstream OFDMA frame. In an embodiment, the translation of EPON upstream time grants to OFDMA resources ensures that Coaxial Network Units (CNUs) sharing an OFDMA frame do not use overlapping subcarriers within the frame. Embodiments further include systems and methods for timing upstream transmissions by the CNUs in order for the transmissions to be received within the same upstream OFDMA frame at a Fiber Coax Unit (FCU). Embodiments further include systems and methods for re-generating a data burst from OFDMA resources for transmission from the FCU to an Optical Line Terminal (OLT). | 03-20-2014 |
| 20140099115 | TRANSMITTING APPARATUS, RECEIVING APPARATUS, OPTICAL FREQUENCY DIVISION MULTIPLEX TRANSMISSION SYSTEM, AND OPTICAL SIGNAL COMMUNICATION METHOD - A transmitting apparatus is used in an electrical frequency division multiplex transmission system including nodes that are on an optical transmission path and that respectively frequency-multiplex a sub-carrier of a unique frequency and a carrier wave to transmit information to a receiving apparatus on the optical transmission path. The transmitting apparatus is disposed in each node and includes a determining unit that receives an input of information concerning unused sub-carriers of a transmission signal in the optical transmission path and determines transmission of the information to the receiving apparatus using an unused sub-carrier; an electrical frequency division multiplex transmission unit that using a frequency of the unused sub-carrier determined by the determining unit, modulates the input information to be transmitted to the receiving apparatus; and a coupling unit that adds to the transmission signal in the optical transmission path, a modulated modulation signal. | 04-10-2014 |
| 20140099116 | Resource-Efficient Digital Chromatic Dispersioin Compensation in Fiber Optical Communication Using Spectral-Shaping Subcarrier Modulation - An optical receiver comprising a frontend configured to receive an optical signal and convert the optical signal into a plurality of digital electrical signals comprising a plurality of spectrally shaped subcarrier signals carrying symbol mapped data information, and a digital signal processor (DSP) unit coupled to the frontend and configured to receive the digital signals from the frontend, demulitplex the digital signals into the subcarrier signals, and compensate chromatic dispersion (CD) for each of the subcarrier signals by applying an equalizer, wherein each of the subcarrier signals is associated with a unique tone frequency and a unique spectral shape. Also disclosed is an optical transmitter comprising a digital signal processor (DSP) unit configured to map data symbols onto a plurality of electrical subcarrier signals that are non-overlapping and spectrally shaped in a frequency domain. | 04-10-2014 |
| 20140133859 | Method and Apparatus of Managing Bandwidth Allocation for Upstream Transmission in a Unified Optical-Coaxial Network - A method of allocating upstream bandwidth on a network comprising mapping an integer portion of a value obtained from a grant start time into a symbol number of a data frame on a coaxial segment of the network, wherein the value comprises the grant start time in units of a length of a data frame in the coaxial segment of a network, and wherein the length of the data frame comprises a preselected number of units of time defined in an optical segment of a network; mapping a fractional portion of the value obtained from the grant start time into a subcarrier number of the data frame; and mapping a grant length into a number subcarriers of the data frame. | 05-15-2014 |
| 20140133860 | Individual Information in Lower and Upper Optical Sidebands - This disclosure is directed to an optical transmitter arrangement | 05-15-2014 |
| 20140147119 | OPTICAL SIGNAL PROCESSING APPARATUS AND OPTICAL SIGNAL PROCESSING METHOD - An optical signal processing apparatus includes a mixer and a first optical modulator. The mixer modulates a carrier signal of a first specific frequency received from a first oscillator with an information signal to generate a subcarrier modulated signal. The first optical modulator optically modulates, with the subcarrier modulated signal received from the mixer, carrier light optically modulated by a second optical modulator at a second specific frequency received from a second oscillator to generate and output modulated carrier light. | 05-29-2014 |
| 20140199073 | CHANNEL ESTIMATION IN OPTICAL COMMUNICATION BASED ON ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING - Techniques for optical communications using optical orthogonal frequency division multiplexing (OFDM) include operating a signal transmitter to modulate laser light to produce modulated light that carries, in optical domain, OFDM subcarriers for carrying communication information, without a frequency guard band between the OFDM subcarriers, and pilot subcarriers for channel estimation at a signal receiver, each pilot subcarrier being free of communication information, and controlling optical power of the pilot subcarriers to vary with optical frequencies of the pilot subcarriers so that optical power of a pilot subcarrier at a high optical frequency is different from optical power of another pilot subcarrier at a low optical frequency. | 07-17-2014 |
| 20140212140 | METHOD AND APPARATUS FOR GENERATION OF FREQUENCY- AND PHASE-LOCKED SUBCARRIER - We describe and demonstrate a novel and simple scheme to generate flattened optical subcarriers using only phase modulators driven by single frequency fundamental sinusoidal sources. 160.8 Gb/s PM-QPSK experiment over a single subcarrier has been demonstrated. | 07-31-2014 |
| 20140241727 | COMMUNICATION BETWEEN TRANSCEIVERS USING IN-BAND SUBCARRIER TONES - The invention relates to a system and method of communication between optical transceivers in an optical WDM network, wherein a broad-band modulation of optical signals in a primary frequency band is utilized for transmitting primary high-speed data, while a plurality of relatively low-frequency in-band subcarriers is used to modulate the optical signals to transmit secondary data between network nodes, wherein the plurality of low-frequency subcarriers lie at least in part within the primary frequency band. | 08-28-2014 |
| 20140248055 | METHOD AND APPARATUS FOR USING DIRECT WIRELESS LINKS AND A CENTRAL CONTROLLER FOR DYNAMIC RESOURCE ALLOCATION - A method and apparatus for short range multi-device communications in personal area networks (PANs) using Terahertz bands. | 09-04-2014 |
| 20140270777 | WIDE BANDGAP MATRIX SWITCHER, AMPLIFIER AND OSCILLATOR - An electronic device comprising an optical gate, an electrical input an electrical output and a wide bandgap material positioned between the electrical input and the electrical output to control an amount of current flowing between the electrical input and the electrical output in response to a stimulus received at the optical gate can be used in wideband telecommunication applications in transmission of multi-channel signals. | 09-18-2014 |
| 20140294393 | OPTICAL OFDM TRANSMISSION - A method for transmitting digital information having a predetermined bit-rate (B) via a nonlinear optical channel includes determining a combination of transmission parameters comprising a number (N) of subcarriers, an information symbol rate (S) for each subcarrier, and a number (b) of bits per symbol on each subcarrier, such that B=NSb. An optical signal is generated comprising the plurality (N) of orthogonal optical subcarriers. Each subcarrier is modulated to carry a proportion (Sb/B) of the total bit-rate (B) of the digital information. The optical signal is then transmitted to a corresponding optical receiver via the nonlinear optical channel. The received signal has a measurable signal quality (Q) which is a function of the transmission parameters (N, S, b). Determining the combination of transmission parameters comprises selecting the parameters such that the associated signal quality is greater than a corresponding quality for a single-carrier transmission, and greater than a corresponding quality employing a larger number (M>N) of subcarriers. | 10-02-2014 |
| 20140301734 | Optimizing Optical Systems Using Code Division Multiple Access and/or Orthogonal Frequency-Division Multiplexing - An optical receiver comprises an optical port configured to receive an encoded optical signal, and a demodulation block indirectly coupled to the port and comprising a multiplexer, wherein the multiplexer is configured to receive an encoded electrical signal, wherein the encoded electrical signal is associated with the encoded optical signal, and wherein the encoded electrical signal is encoded using a code division multiple access (CDMA) scheme, receive a code associated with the scheme, perform a dot multiplication of the encoded electrical signal and the code, and generate a differential voltage based on the dot multiplication. | 10-09-2014 |
| 20140314415 | CROSSTALK REDUCTION IN OPTICAL NETWORKS USING VARIABLE SUBCARRIER SPECTRAL ALLOCATION - A method and system for reducing crosstalk among subcarriers of a super-channel may apply a frequency shift to selected intermediate subcarrier bands upon optical modulation. The frequency shift may be applied to equally spaced optical frequencies between a first optical frequency and a last optical frequency respectively corresponding to two end subcarrier bands that define a fixed bandwidth of the super-channel. The frequency shift may result in the intermediate subcarrier bands being optically modulated at variably spaced optical frequencies within the fixed bandwidth of the super-channel. | 10-23-2014 |
| 20140314416 | CROSSTALK REDUCTION IN OPTICAL NETWORKS USING VARIABLE SUBCARRIER POWER LEVELS - A method and system for reducing crosstalk among subcarriers of a super-channel may involve adjusting power levels of the subcarriers. In one example, power levels of edge and/or intermediate subcarriers may be reduced relative to center subcarriers in the super-channel band. The adjustment in power level may lead to overall reduction in optical signal-to-noise ratio degradation. | 10-23-2014 |
| 20150125152 | POWER EFFICIENT SUBCARRIER AGGREGATOR AND SUBCARRIER COMBINER FOR MULTI-DIRECTION VARIABLE OPTICAL TRANSCEIVER - A multi direction variable transceiver including a transmitter comprising a subcarrier aggregator including at least one variable transmitter splitter and at least one variable transmitter coupler. The transceiver typically includes a receiver having at least one variable receiver splitter and at least one variable receiver coupler. In some examples, each of the transmitter and the receiver may include a controller for dynamically adjusting a splitting ratio for at least one of the variable receiver splitter, variable receiver coupler, variable transmission splitter and variable transmission coupler. | 05-07-2015 |
| 20150131999 | TRANSCEIVER FOR USE IN FIBRE NETWORK - A method performed by a transceiver for use in fibre network for sending and/or receiving signals. Transceiver includes SCM device; laser diode; Red-Blue Filter, RBF, having red, blue and common channels; PD; and Subcarrier Demultiplexing, SCDM, device. SCM device receives electromagnetic signals on at least two input ports, multiplexes electromagnetic signals and outputs signal to laser diode. Laser diode receives signal, converts signal to optical signals comprising plurality of subcarriers of different frequencies distributed in frequency around main optical carrier, and outputs subcarriers to red channel of RBF. RBF receives subcarriers and outputs to the fibre network via common channel. RBF receives subcarriers on common channel and filters out blue frequencies and outputs to photo diode. Photodiode receives the subcarriers having blue wavelengths, converts subcarriers into electromagnetic signal and outputs electromagnetic signal to SCDM device. SCDM device demultiplexes electromagnetic signal into at least two electromagnetic signals and outputs. | 05-14-2015 |
| 20150318931 | Pre-Distortion of an Optical Signal with Frequency Division Multiplexed Sub-Carriers - A method is provided for pre-distorting an optical signal, intended to be transmitted over an optical transmission line and including a plurality of frequency division multiplexed optical sub-carriers. The optical signal is obtained from an optical conversion of an electrical signal including a plurality of frequency division multiplexed sub-carriers. This method includes obtaining a plurality of corrective factors, corresponding to the electrical sub-carriers, as a function of a plurality of values, determined for the optical sub-carriers, of a first parameter dependent on the power of the sub-carriers, and application of the corrective factors to the amplitudes of the corresponding electrical sub-carriers, so as to equalize, at the output of the optical transmission line, the values of the first parameter for the sub-carriers of the optical signal. | 11-05-2015 |
| 20160006530 | SYSTEM AND METHOD FOR OFDM SYMBOL INTERLEAVING - An orthogonal frequency division multiplexing (OFDM) transmitter that includes an encoder, an interleaver, a symbol processor; and a transmission module; wherein the encoder is configured to encode a superframe to provide an encoded superframe; wherein the encoded superframe comprises a sequence of encoded frames; wherein the interleaver is configured to allocate multiple frequency sub-bands to each encoded frame of the encoded superframe by assigning adjacent frequency sub-bands to successive symbols of each encoded frame; wherein the symbol processor is configured to generate, for each encoded frame and according to the assignment of the multiple frequency sub-bands, an intermediate set of symbols; and wherein the transmission module is configured to transmit simultaneously, for each encoded frame, OFDM symbols that represents the intermediate set of symbols. | 01-07-2016 |
| 20160028577 | RECEPTION OF 2-SUBCARRIERS COHERENT ORTHOGONAL FREQUENCY DIVISION MULTIPLEXED SIGNALS - A dual-polarization, 2-subcarriers code orthogonal, orthogonal frequency division multiplexed signal carrying information bits is transmitted in an optical communication network without transmitting a corresponding pilot tone or training sequence. A receiver receives the transmitted signal and recovers information bits using a blind equalization technique and by equalizing the 2-subcarriers OFDM signal as a 9-QAM signal in time domain with a CMMA (constant multi modulus algorithm) equalization method. | 01-28-2016 |
| 20160080180 | FULL-OPTICAL MULTIWAVELET ORTHOGONAL FREQUENCY DIVISIONAL MULTIPLEXING (OFDM) AND DEMULTIPLEXING - Aspects of embodiments relate to an optical wavelet transform (WT) or inverse wavelet transform (IWT) medium for implementing optical multiwavelet orthogonal Frequency Division Multiplexing (OFDM) or optical demultiplexing. In embodiments, the optical WT/IWT medium comprises a plurality of N waveguides for receiving in parallel a corresponding number of N modulated optical input signals λ | 03-17-2016 |
| 20160087740 | HALF-CYCLED ORTHOGONAL FREQUENCY DIVISIONAL MULTIPLEXING TRANSMISSION AND RECEPTION - An optical transmitter transmits an orthogonal frequency division multiplexing symbol in which only one-half of available subcarriers are modulated with data and the remaining subcarriers are suppressed by not modulating with data. The transmission is of duration equal to half the symbol period of the OFDM symbol, resulting in a half-cycle transmission. An optical receiver receives the half-cycle transmission OFDM symbol, regenerates the full time domain representation and recovers data modulated on the one-half of available subcarriers. The modulated subcarriers and the suppressed subcarriers alternate in the frequency domain. | 03-24-2016 |
| 20160112235 | SIGNAL MODULATION METHOD, SIGNAL DEMODULATION METHOD, SIGNAL MODULATION APPARATUS, SIGNAL DEMODULATION APPARATUS AND SIGNAL TRANSMISSION SYSTEM - The present invention discloses a signal modulation method, including: demultiplexing an input signal into 2N sub-signals; grouping every two of the 2N sub-signals into a pair; performing filtering on two sub-signals in each pair; performing carrierless amplitude phase (CAP) modulation on the two sub-signals in each pair; modulating the two sub-signals in each pair to a same frequency band, to generate N pairs of CAP signals, where frequency bands of different pairs of sub-signals are different, and a spacing between center frequencies of two neighboring frequency bands is greater than or equal to an average value of baud rates of sub-signals corresponding to the two neighboring frequency bands; and combining the N pairs of CAP signals, and performing electro-optic modulation on a signal obtained after the combining. A signal demodulation method corresponding to the signal modulation method is further disclosed. | 04-21-2016 |
| 20160119077 | Dual-Channel Orthogonal Carriers Assisted Optical Signal Transmitting Device, Direct Detection Method and System - The present disclosure relates to a dual-channel orthogonal carriers assisted optical signal transmitting device, and a direct detection method and a direct detection system using the dual-channel orthogonal carriers assisted optical signal. The direct detection system using the dual-channel orthogonal carriers assisted optical signal comprises a transmitting device and a receiving device. The transmitting device is configured to generate and transmit a dual-channel orthogonal carriers assisted optical signal to be detected, wherein the dual-channel orthogonal carriers assisted optical signal is modulated with a modulation signal. The receiving device is configured to receive the dual-channel orthogonal carriers assisted optical signal, and recover amplitude and phase information of the modulation signal based on the dual-channel orthogonal carriers assisted optical signal. | 04-28-2016 |
| 20160119090 | TRANSMISSION APPARATUS AND TRANSMISSION METHOD - A transmission apparatus includes: a first obtaining section configured to obtain a first transmission characteristic in communication of a multi-carrier signal through a transmission path between the transmission apparatus and a distant transmission apparatus; a second obtaining section configured to obtain a second transmission characteristic under a predetermined usage condition within a specified performance range of the transmission apparatus; a correcting section configured to correct the first transmission characteristic according to the second transmission characteristic; and a determining section configured to determine an amount of allocation for each subcarrier included in the multi-carrier signal, according to the first transmission characteristic that has been corrected by the correcting section. | 04-28-2016 |
| 20160127049 | REDUCTION OF EFFECTS OF SIGNAL-SIGNAL BEAT INTERFERENCE IN OPTICAL TRANSPORT SYSTEMS - Disclosed herein is an optical transport system configured to transport an amplitude-modulated optical signal generated at the transmitter using single-sideband modulation of an optical carrier and detected at the receiver using direct optical detection. The receiver is configured to estimate the level of signal-signal beat interference (SSBI) in the electrical signal generated upon direct detection of the received optical signal by first converting this electrical signal into a modified baseband signal configured for single-sideband modulation and then squaring and appropriately scaling this modified baseband signal. The receiver is further configured to subtract the estimated level of SSBI from the electrical signal generated by the direct optical detector and to process the resulting corrected electrical signal to recover the data encoded in the amplitude-modulated optical signal. Example analog and digital circuits for estimating the level of SSBI at the receiver are disclosed. | 05-05-2016 |
| 20160149742 | MULTI-WAVEBAND OFDM RECEIVER, AND FREQUENCY OFFSET COMPENSATION METHOD AND SYSTEM - A multi-waveband OFDM receiver and a frequency offset compensation method and system are disclosed. The method includes: performing single waveband frequency offset estimation on an optical comb line of each order; classifying the optical comb lines into a low mutation optical comb line and a high mutation optical comb line; performing joint frequency offset estimation on the low mutation optical comb line; and performing compensation for a frequency offset of a radio frequency drive signal by using an estimated joint frequency offset. The present invention improves accuracy and reliability of the frequency offset estimation of the radio frequency drive signal, so that the degree of the compensation for the frequency offset of the radio frequency drive signal is more comprehensive and accurate. | 05-26-2016 |
| 20160173304 | SIGNAL GENERATING APPARATUS AND SIGNAL GENERATING METHOD | 06-16-2016 |
| 20160182180 | METHOD FOR BASE STATION BACKHAUL, RELATED DEVICE AND SYSTEM FOR BASE STATION BACKHAUL | 06-23-2016 |
| 20190149243 | ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SINGLE SIDEBAND TRANSMISSION OVER A WAVEGUIDE | 05-16-2019 |
