Abstract: Methods for beam adjustment are disclosed. A method includes: determining, by a first node, whether a beam adjustment is required; and when the beam adjustment is required, at least adjusting, by the first node, its beam, or informing, by the first node, a neighboring second node of adjusting the second node's beam, so that relationship between the beam of the first node and the beam of the second node meets a preset condition. There are also provided associated nodes.

Abstract: A modulator spreads the spectrum of a generated clock to reduce Electro-Magnetic Interference (EMI). A capacitor is charged by a variable current to generate a ramp voltage that is compared to a reference to end a clock cycle and discharge the capacitor. An up-down counter drives a Digital-to-Analog Converter (DAC) that controls the variable charging current to provide triangle modulation. A smaller offset current is added or subtracted for cubic modulation when the up-down counter reaches its minimum count. A frequency divider that clocks the up-down counter also clocks a Linear-Feedback Shift-Register (LFSR) to that controls pseudo-random current sources that further modulate variable current and frequency. The LFSR is clocked with the up-down counter to modulate each frequency step, or only at the minimum count to randomly modulate at the minimum frequency. Binary-weighted bits from the up-down counter to the DAC are swapped to modulate the frequency step size.

Abstract: A vehicle computer includes a watermark memory and a watermark processor programmed to execute instructions stored in the watermark memory. The instructions executed by the watermark processor include receiving an image captured by a camera, selecting a set of random pixel locations, generating a random watermark, and embedding the random watermark into the image at the set of random pixel locations. Another vehicle computer includes a validation memory and a validation processor programmed to execute instructions stored in the validation memory. The instructions executed by the validation processor include receiving a watermarked image, determining a random watermark, detecting an embedded watermark in the received watermarked image by selecting a set of random pixels and analyzing the selected set of random pixels for the random watermark, and authenticating the watermarked image as a result of determining that the watermarked image includes the random watermark at the set of random pixel locations.

Abstract: A driving method of a display panel includes the steps of: using a timing controller chip to receive a first data signal of a control board; using the timing controller chip to convert the first data signal into a second data signal; using the timing controller chip to generate a variable-frequency first clock signal, and to transmit the second data signal and the first clock signal to a source driving chip; and using the timing controller chip to obtain the first clock signal and generate a second clock signal by frequency multiplication, the second clock signal being a preset multiple of that of the first clock signal; wherein the second clock signal serves as an internal clock signal of a power supply chip circuit, and the second clock signal is inputted to the power supply chip circuit.

Abstract: Apparatus and methods are provided multiple transmission. In one novel aspect, TCI-state indication for non-coherent joint transmission (NCJT) channel station information (CSI) reporting is provided. The UE receives NCJT from at least a first transmission from a first transmission point (TRP) and a second transmission from a second TRP, determines a receiving (RX) spatial filter information for the NCJT and acquires channel state information (CSI) according to a report setting based on the determined RX spatial filter to simultaneously acquire at least two channel measurement resources (CMRs) and one interference measurement resource (IMR), wherein at least one CMR is from the first TRP and at least one CMR is from the second TRP. In one embodiment, the RX spatial filter information is determined based on a group-based beam reporting procedure performed by the UE. In another embodiment, the RX spatial filter information is determined based on TCI-state received from the wireless network.

Abstract: A receiving device in a communication system is provided. The communication system includes at least one processor configured to estimate noise power on a frequency channel by despreading a reception on the frequency channel using at least one non-assigned despreading code. The at least one non-assigned despreading code corresponds to at least one spreading code that is unused by transmitting devices in the communication system on the frequency channel.

Abstract: The present disclosure relates to a radio frequency power amplifier (RFPA) control device. The RFPA control device may include an input signal processing module configured to process an input signal into two signals. A first signal may be used for signal detection, and a second signal may be used for signal amplification. The RFPA control device may also include a delay module. The delay module may be disposed between the input signal processing module and an adjustment module. The delay module may be configured to determine a delay of the second signal such that the second signal and the control signal roughly simultaneously reach the adjustment module.

Abstract: An optical communication system includes an optical transmitter and one or more processors. The optical transmitter is configured to output an optical signal, and includes an average-power-limited optical amplifier, such as an erbium-doped fiber amplifier (EDFA). The one or more processors are configured to receive optical signal data related to a received power for a communication link from a remote communication system and determine that the optical signal data is likely to fall below a minimum received power within a time interval. In response to the determination, the one or more processors are configured to determine a duty cycle of the optical transmitter based on a minimum on-cycle length and a predicted EDFA output power and operate the optical transmitter using the determined duty cycle to transmit an on-cycle power that is no less than the minimum required receiver power for error-free operation of the communication link.

Abstract: At least some aspects of the present disclosure provide for a system. In some examples, the system includes a pulse width modulation (PWM) generator configured to generate a PWM signal. The PWM generator generates the PWM signal by generating a first signal having a first dithering profile and a first frequency bandwidth, generating a second signal having a second dithering profile and a second frequency bandwidth greater than the first frequency bandwidth, modulating the second signal with the first signal to generate a dual random spread spectrum signal, and generating the pulse width modulation signal according to the dual random spread spectrum signal.

Abstract: Systems and methods for rapidly finding detectable signals within the field-of-view of a phased array antenna. The transmit beam pattern is modified over time to increase signal spatial search performance over typical time-delay steering by producing a coarse-to-fine angular beam pattern with a tree-based approach to signal detection. A tree-based beam search is employed to select a beam having a narrower beamwidth for transmission at an angle from boresight that lies in an angular space where a signal has been previously detected.

Abstract: A method for spread spectrum communication, a user equipment and a base station are provided in embodiments of the present disclosure. The method for spread spectrum communication applied to a user equipment includes: selecting spreading sequences for a plurality of symbols of data to be transmitted in a set of spreading sequences, respectively, wherein spreading sequences selected for at least two symbols are different; spreading the data by using the selected spreading sequences; transmitting the spread data.

Abstract: A transmitter module for a broadband data transmission system for radio communications, comprising at least one polyphase FFT filter bank is described. The at least one polyphase FFT filter bank is established as a synthesis polyphase FFT filter bank, wherein the at least one polyphase FFT filter bank comprises several filter units, wherein the transmitter module is configured to receive an input signal comprising a symbol sequence, and wherein the transmitter module is configured to transmit a signal based on the received input signal. Moreover, a receiver module for a broadband data transmission system and a data transmission system are described.

Abstract: A device may utilize a cable that includes connectors and conductors to transfer signals, electrical power, or both. Some cable failures result in an inability to transfer signals. Other failures may result from different cables being used at different times, resulting in a mismatch in which the cable is rated to transfer less power than what could otherwise be delivered by the power source. Parameters, such as cable impedance, transmitter gain, signal conditioning, and so forth that are associated with use of the cable are monitored at different times. If the values of these parameters from one time to another exceed a threshold value, a fault in the cable is determined. A notification about the impending or actual failure of the cable may be presented, and a suitable cable may be recommended for purchase. For example, a hyperlink may be provided to allow for purchase of the suitable cable.

Abstract: According to one embodiment, an IC card includes an antenna, a first oscillator, and a first processor. The first oscillator is configured to output a first clock signal of a first frequency, and output a second clock signal of a second frequency that is higher than the first frequency as requested. The first processor is configured to operate based on the first clock signal when not during an execution period of first processing corresponding to a reception command received by the antenna, request the second clock signal for executing the first processing, and execute the first processing based on the second clock signal of the first oscillator that receives the request.

Abstract: The present invention relates to a method for generating a security identifier for a control unit (10) of a battery system (100), comprising the steps of supplying an operation voltage to the control unit (10), outputting calibration data from a non-volatile memory element (15a) of the control unit (10), and generating a security identifier from the calibration data using a security algorithm. Therein, the calibration data is based on at least one testing process performed on the control unit (10) and is required for a faultless operation of the control unit (10). Further, according to a method for generating an activation key for a control unit (10) of a battery system (100) an activation key is generated based on such security identifier and output from the control unit (10). The invention further relates to an activation method for such control unit (10), wherein a control unit (10) is activated in response to the validation of such security identifier.

Abstract: There is provided a wireless communication apparatus and wireless communication method, which can perform information transfer, while suppressing interference to other terminal stations, and preventing a reduction of a transmission opportunity of other terminal stations. By causing the transmission power to be reduced, at the time when a traffic amount to be transmitted and received by itself increases, a terminal station which performs wireless access based on CSMA on a mesh network can suppress interference to other surrounding terminal stations, and can prevent a reduction of a transmission opportunity of other terminal stations. By measuring the number of and sizes of packets to be transmitted and received, it is possible for a terminal station to comprehend the traffic amount to be transmitted and received by itself, and perform a control of the transmission power by this.

Abstract: The disclosure relates to measuring a parameter of a lithographic process and a metrology apparatus. In one arrangement, radiation from a radiation source is modified and used to illuminate a target formed on a substrate using the lithographic process. Radiation scattered from a target is detected and analyzing to determine the parameter. The modification of the radiation comprises modifying a wavelength spectrum of the radiation to have a local minimum between a global maximum and a local maximum, wherein the power spectral density of the radiation at the local minimum is less than 20% of the power spectral density of the radiation at the global maximum and the power spectral density of the radiation at the local maximum is at least 50% of the power spectral density of the radiation at the global maximum.

Abstract: Methods and apparatuses enabling uplink multiple-input multiple-output (MIMO) are provided. A user equipment (UE) includes a transceiver and a processor operably connected to the transceiver. The transceiver is configured to receive an uplink (UL) grant for an UL transmission. The processor is configured to decode a precoding information field in downlink control information (DCI) associated with the UL grant. The precoding information field includes at least one precoding matrix indicator (PMI) corresponding to a plurality of precoders. The transceiver is further configured to precode a data stream according to the precoders indicated by the precoding information field and transmit the precoded data stream on an UL channel.

Abstract: A node is provided that is configured to communicate in a cooperative broadcast multi-hop network that employs broadcast flood routing and multi-hop transmission using a direct-sequence spread-spectrum (DSSS) waveform. The node includes an antenna and a waveform module having a receiver processing chain. The antenna can receive a plurality of DSSS signals from other nodes on a particular channel, and output a channel that includes the plurality of DSSS signals. The plurality of DSSS signals include transmissions that are directly received from other nodes and multi-path components of those transmissions. The receiver processing chain can include a multi-user RAKE receiver that can combine, when performing demodulation processing, a plurality of transmissions directly received from the other nodes and multipath components of transmissions received from the other nodes. In some implementations, the node can perform cooperative beamforming and adaptive space-spectrum whitening.

Abstract: Embodiments of the present disclosure provide methods, systems, apparatuses, and computer program products for an improved communication network. In one embodiment, a method is provided comprising receiving, at a first device, a first signal over a first medium, the signal comprising a first portion and a second portion, and extracting by a processor a third portion of the first signal, the third portion being at least a portion of the first portion of the first signal, the third portion being intended for receipt by a second device associated with a particular user account. The method may further include combining at least a fifth portion of the first signal with the third portion of the first signal to generate a second signal, the fifth portion of the first signal being at least a portion of the second portion of the first signal and providing the second signal to the second device.

Abstract: A spread spectrum clock generating system is provided. The digital frequency detecting unit is configured for receiving a reference signal and a feedback signal and for comparing the reference signal and the feedback signal to generate a frequency difference signal. The digital loop filtering unit is signally connected to the digital frequency detecting unit and outputs a clock controlling signal based on the frequency difference signal. The digital spread spectrum controlling unit is configured for receiving the reference signal to output a spread spectrum signal. The digital-analog converting unit is configured for converting the clock controlling signal to a first controlling signal and for converting the spread spectrum signal to a second controlling signal. The analog controlled oscillating unit is configured for receiving the first controlling signal and the second controlling signal to output a spread spectrum clock signal.

Abstract: A frequency hopping Global Positioning System (GPS) system comprises an on-orbit reprogrammable digital waveform generator configured to generate a GPS signal comprising a resilient frequency-hopping spread spectrum GPS signal that hops at a hop rate between two or more GPS channels. The GPS signal further comprises a legacy direct-sequence spread spectrum signal for at least two of the two or more GPS channels. Further, a receiver is configured to receive the GPS signal, wherein the receiver is further configured to decode the GPS signal.

Abstract: A method and an apparatus may be used for positioning a terminal device. Positioning measurement information for a terminal device is obtained by using a measurement apparatus on the terminal device side and/or an access node side, where the positioning measurement information is multipath positioning measurement information that is based on a single access node, and includes positioning measurement information of a main path and at least one reflection path that are based on the single access node, or positioning measurement information for at least two reflection paths. The measurement apparatus on the terminal device side and/or the access node side reports the positioning measurement information to a positioning function entity in a network, so that the positioning function entity can perform location estimation on the terminal device based on the positioning measurement information, to position the terminal device.

Abstract: A method (50) for estimating a frequency shift and a frequency drift affecting a useful signal including a code word formed by a channel encoder, including an analysis phase (51) including: for two analysis frequency drifts: a compensation (52) of the analysis frequency drift on the useful signal, an estimation (53) of the frequency shift on each useful signal obtained after compensation, a selection (54) of frequency hypotheses, and an estimation phase (55) including: for each frequency hypothesis: a frequency recalibration (56) of the useful signal depending on the frequency hypothesis, in order to obtain sample sequences, an evaluation (57) of the probability of each sample sequence to be a code word of said channel encoder, an estimation (58) of the frequency shift and of the frequency drift depending on the most probable frequency hypothesis.

Abstract: Embodiments of the present disclosure relate to the field of communication technologies, and provide a method and an apparatus for bandwidth filtering based on deep learning, a server and a storage medium. In the present disclosure, a bandwidth data of a server is obtained in real time (101), the obtained bandwidth data is input into a deep neural network model (102), and an output result of the deep neural network model is taken as filtered output bandwidth data obtained after filtering the input bandwidth data (103), where the deep neural network model is obtained through training according to historical bandwidth data and output bandwidth data obtained after filtering the historical bandwidth data.

Abstract: To provide a radar device, capable of eliminating the influence based on the local feedthrough in the FMCW radar device. There is provided a radar device including: an oscillator configured to oscillate a local signal; a transmitting antenna configured to emit a transmission signal based on the local signal; a receiving antenna configured to receive a reflected wave in which the transmission signal is reflected from a target; a mixer configured to multiply the reflected wave and the local signal by each other to produce a multiplied signal; and a first shifter provided between the oscillator and the mixer and configured to shift a phase of the local signal.

Abstract: A blockchain may be used as a stochastic timer. The posting of a blockchain solution for verification may be a trigger that determines an event schedule. Because the only entity that knows when the solution will be posted is the solving entity, the solving entity may be rewarded with the ability to potentially exploit this knowledge. However, because the solving of a blockchain is a competitive process, there is a risk that if the solving entity retains the solution for greater exploitation, then another entity will post the solution and therefore gain the benefit. A blockchain stochastic timer can thus provide the necessary incentive for entities to invest computational resources into blockchain solutions.

Abstract: Systems, devices, and methods are provided for mixed-mode signal processing that achieves unprecedented levels of out-of-band and in-band interference suppression. Embodiments of the present disclosure mitigate the effects of blockers and jammers, which have surfaced as issues in emerging cognitive radio systems as those networks struggle to co-exist with licensed and unlicensed users.

Abstract: Noise cancellation techniques based on differential filtering, and front-end modules and wireless devices incorporating same. An example of a front-end module includes transmit, receive, and antenna contacts, and a duplexer including a first transmit filter connected in a transmit path between the transmit contact and the antenna contact, and a first receive filter connected in a receive path between the antenna contact and the receive contact, the first transmit filter having a differential input. In one example, the front-end module includes a power amplifier module connected in the transmit path and configured to supply a differential transmit output on first and second differential signal lines connected to the differential input of the first transmit filter, and a first bandpass filter connected between the first and second differential signal lines and configured to provide a first frequency-specific short between the first and second differential signal lines.

Abstract: Multipath filters are provided herein. In certain configurations, a multipath filter includes multiple filter paths or circuit branches that are electrically connected in parallel with one another between an input terminal and an output terminal. The input terminal receives an input signal, and each filter circuit branch includes a double-in double-switched (DIDS) downconverter that downconverts the input signal with two different clock signal phases to generate a downconverted signal. Each filter circuit branch further includes a filter network that generates a filtered signal by filtering the downconverted signal and an upconverter that upconverts the filtered signal to generate a branch output signal. Additionally, the branch output signals from the filter circuit branches are combined to generate an output signal at the output terminal.

Abstract: Provided are a method and device for designing and optimizing a multi-degree-of-freedom frequency-modulation (FM) signal, and a computer storage medium. The method includes that: a time domain function of the multi-degree-of-freedom FM signal is determined; the constraint condition and the objective function of multi-degree-of-freedom FM signal optimization are established; an algorithm model of augmented Lagrangian genetic algorithm is determined based on the constraint condition and the objective function; characteristic parameters of the first iteration of the algorithm model are initialized, where the characteristic parameters of the first iteration at least include the Lagrange multiplier of the first iteration and the offset of the first iteration; initialization signal of the multi-degree-of-freedom FM signal is acquired, and initialization frequency control points of the initialization signal are determined based on the initialization signal.

Abstract: An on-chip balun comprising a primary side, a secondary side, and an integrated notch filter.

Abstract: A timing controller of a display panel includes a spread spectrum clock generator (SSCG) and a control circuit block. The SSCG performs a spread spectrum operation on a clock signal to output a modulated clock signal having a varying frequency that varies with a fixed pattern, wherein a complete cycle of the frequency variation occurs in a frequency modulation period. The control circuit block outputs display data for the display panel within a data output period related to the modulated clock signal, and outputs a synchronization signal to another timing controller of the display panel, such that the another timing controller synchronizes a spread spectrum operation performed thereby with that performed by the SSCG.

Abstract: There is provided a 2-stage moving average filter for a navigation device including a delta regulator and an N-taps average circuit. The delta regulator is used as a first stage to receive motion delta at a varied frequency, and combine or split the received motion delta to output a regulated motion delta at a fixed frequency. The N-taps average circuit receives and averages N regulated motion delta and outputs the averaged motion delta at a fixed frequency.

Abstract: In the multiple short sequence based SRS, multiple items of sequence data having a short sequence length corresponding to a partial band are used for transmitting SRS in discontinuous bands. In the multiple short sequence based SRS, a terminal specifies a frequency domain to be used for transmitting a reference signal using predetermined sequence data, applies a phase shift index associated with the specified frequency domain to the reference signal, and transmits the reference signal to which the phase shift index is applied by using the specified frequency domain.

Abstract: A self-localizing apparatus uses timestampable signals transmitted by transceivers that are a part of a distributed localization system to compute its position relative to the transceivers. Transceivers and self-localizing apparatuses are arranged for highly accurate timestamping using digital and analog reception and transmission electronics as well as one or more highly accurate clocks, compensation units, localization units, position calibration units, scheduling units, or synchronization units. Transceivers and self-localizing apparatuses are further arranged to allow full scalability in the number of self-localizing apparatuses and to allow robust self-localization with latencies and update rates useful for high performance applications such as autonomous mobile robot control.

Abstract: A system for transmitting data over an optical communication path is configured to receive data to be encoded in a bitstream for transmission using an optical communication path and encodes the received data to obtain a bitstream. The system is further configured to determine that the bitstream includes a sequence of consecutive bits, and obtain a power level at which to transmit a portion of the bitstream based on a count of the consecutive bits in the sequence. The system may be configured to selectively activate a light source at a power level according to a modulation scheme to optically transmit the portion of the bitstream at the power level.

Abstract: Disclosed is receiver apparatus including a first input configured to receive a first signal, a second input configured to receive a second signal, a switching circuit configured to alternate between the first and second signal from the first and second inputs, a receiver configured to sample the input signal to produce a plurality of input samples, a reference sequence generator configured to generate a reference signal, and a correlator configured to correlate the first and second signals with the reference signal to detect a correlation event, the correlator including a first buffer configured to receive signals from the first input and a second buffer configured to receive signals from the second input, wherein the correlator is configured to process the first signal in the first buffer, while the second buffer receives the second signal.

Abstract: An apparatus includes feeds to form analog beams. The feeds are divided into panels. The apparatus includes processing circuitry that divides a target area for communications coverage into regions, including a first region and a second region neighboring each other. The processing circuitry generates, for the first region, a first plurality of analog beams, forming a first cluster. The processing circuitry generates, in the first cluster from the first plurality of analog beams, a first plurality of hybrid beams arranged in a first arrangement in the first cluster. The processing circuitry generates, for the second region, a second plurality of analog beams, forming a second cluster. The processing circuitry generates, in the second cluster from the second plurality of analog beams, a second plurality of hybrid beams arranged in a second arrangement that is adjacent to the first plurality of hybrid beams in the first arrangement.

Abstract: A system that incorporates the subject disclosure may include, for example, a method for measuring a power level in at least a portion of a plurality of resource blocks occurring in a radio frequency spectrum, wherein the measuring occurs for a plurality of time cycles to generate a plurality of power level measurements, calculating a baseline power level according to at least a portion of the plurality of power levels, determining a threshold from the baseline power level, and monitoring at least a portion of the plurality of resource blocks for signal interference according to the threshold. Other embodiments are disclosed.

Abstract: A method for deinterleaving a plurality of resource units (RUs) where each RU includes data and parameters. The method includes assigning each RU into one of a first deinterleaver and a second deinterleaver and storing the parameters of each respective RU to a respective buffer in an order. The method also includes processing the data of the respective RU in the one of the first deinterleaver and the second deinterleaver and upon completion of the processing of the data of a respective RU, outputting the data of the respective RU from the one of the first deinterleaver and the second deinterleaver into which the respective RU was assigned, outputting the parameters of the respective RU corresponding to one of the first deinterleaver and the second deinterleaver into which the respective RU was assigned, and aligning the parameters of the respective RU with the data of the respective RU based on the order of storage of the parameters in the respective buffer.

Abstract: Ultra-Wideband (UWB) technology exploits modulated coded impulses over a wide frequency spectrum with very low power over a short distance for digital data transmission. Such UWB systems through their receivers may operate in the presence of interfering signals and should provide for robust communications. Accordingly, an accurate and sharp filter that operates at low power is required and beneficially one that does not require a highly accurate power heavy clock. Further, many UWB applications require location and/or range finding of other elements and it would therefore be beneficial to provide a UWB based range finding and/or location capability removing the requirement to add additional device complexity and, typically significant, power consumption.

Abstract: A sub-sampling system that is part of a modulator in a transmitter employing a chaos based architecture and including a symbol mapper and a chaos generator. The system includes M-number of channels each receiving a sequence of chaos samples from the generator and a delay device in all of the channels except one that delay the chaos samples at different delay times. The system also includes a sub-sampler in all of the channels that receive the delayed samples, where each sub-sampler outputs every predetermined one of the chaos samples and a register in each channel each storing a predetermined number of the sub-sampled chaos samples. A selection switch responsive to the stored sub-sampled chaos samples from the registers, where the selection switch is responsive to a selection signal from the symbol mapper that selects one of the registers to output the sequences of stored sub-sampled chaos samples from the system.

Abstract: Embodiments of the present disclosure relate to a method and system to generate a waveform in a communication network. The transmitter receives an input data and transmit a generated waveform to another communication system. The input data is spread with a spread code to generate a spread data and rotated using a constellation rotation operation to produce a rotated data. The rotated data is then precoded using precoding filter to produce a precoded data, and transformed into DFT output data using DFT operation. The DFT output data is then mapped with subcarriers to generate the sub-carrier mapped DFT data and modulated using Orthogonal Frequency Division Multiplexing (OFDM) modulation to generate the waveform with low PAPR.

Abstract: An apparatus is configured to be employed within one or more nodes. The apparatus includes control circuitry. The control circuitry is configured to perform adaptive ranking to generate an alternative ranked set of beam pairs based on an adaptive ranking criteria, where the adaptive ranking criteria includes switching latencies and predicted qualities and select an alternative beam pair of the alternative ranked set of beam pairs.

Abstract: Methods and systems for estimating a symbol timing error for an offset quadrature phase shift keying (O-QPSK) modulated signal. The method includes: receiving a plurality of complex samples representing an O-QPSK modulated signal, wherein if the O-QPSK modulated signal is sampled on time each of the plurality of samples has substantially no imaginary component; generating an early error metric and a late error metric for each sample, the early error metric based on the imaginary component for the sample and a sign of a real component of a previous sample and the late error metric based on the imaginary component for the sample and a sign of a real component of a next sample; generating a combined early error metric based on the early error metrics for the plurality of samples; generating a combined late metric based on the late error metrics for the plurality of samples; and generating an estimate of the symbol timing error based on the combined early error metric and the combined late metric.

Abstract: An optical communication system includes an optical transmitter and one or more processors. The optical transmitter is configured to output an optical signal, and includes an average-power-limited optical amplifier, such as an erbium-doped fiber amplifier (EDFA). The one or more processors are configured to receive optical signal data related to a received power for a communication link from a remote communication system and determine that the optical signal data is likely to fall below a minimum received power within a time interval. In response to the determination, the one or more processors are configured to determine a duty cycle of the optical transmitter based on a minimum on-cycle length and a predicted EDFA output power and operate the optical transmitter using the determined duty cycle to transmit an on-cycle power that is no less than the minimum required receiver power for error-free operation of the communication link.

Abstract: A clock generator including a phase frequency detector configured to compare a phase and a frequency of a reference clock signal with a phase and a frequency of a first output clock signal and generate a detection signal based on a difference in the phases and frequencies of the clock signals; a loop filter configured to generate a first control voltage signal based on the detection signal; a first voltage controlled oscillator configured to generate and output a first output clock signal based on the first control voltage signal, a modulation filter configured to generate a modulation voltage signal based on the reference clock signal and generate a second control voltage signal by combining the modulation voltage signal and the first control voltage signal, and a second voltage controlled oscillator configured to generate and output a second output clock signal based on the second control voltage signal is provided.

Abstract: The present invention relates to a pilot tone generating method and apparatus of an orthogonal frequency division multiple access system and method, and a channel estimation method and apparatus using the same. The channel estimation apparatus includes a pilot tone extracting unit for extracting a pilot tone, which is inserted within a frame with data tone, masked with an orthogonal code; a pilot tone unmasking unit for unmasking of the pilot tone extracted from the pilot tone extracting unit by using an orthogonal code information; and a channel estimation operating unit for estimating a channel by calculating an average of the pilot tones which is unmasked in the unmasking unit.

Abstract: The present invention relates to a pilot tone generating method and apparatus of an orthogonal frequency division multiple access system and method, and a channel estimation method and apparatus using the same. The channel estimation apparatus includes a pilot tone extracting unit for extracting a pilot tone, which is inserted within a frame with data tone, masked with an orthogonal code; a pilot tone unmasking unit for unmasking of the pilot tone extracted from the pilot tone extracting unit by using an orthogonal code information; and a channel estimation operating unit for estimating a channel by calculating an average of the pilot tones which is unmasked in the unmasking unit.