55 results about "Intersymbol interference" patented technology

The invention provides a synchronization adjustment method and system, computer equipment and a storage medium, and relates to the technical field of communication, and the method comprises the steps: obtaining synchronization information and an air interface signal of a current cell where a terminal is located; generating a first time domain signal based on the synchronization information; performing down-sampling processing on the air interface signal to obtain a second time domain signal; performing correlation calculation on the first time domain signal and the second time domain signal to obtain a correlation value sequence; and carrying out weight gravity center estimation on a peak value in the correlation value sequence, determining a timing offset, and adjusting a windowing position according to the timing offset to complete synchronous adjustment. According to the synchronization information disclosed by the invention, the accurate timing position is obtained by carrying out weight-based correlation calculation on the synchronization information and the air interface signal, so that the time drift error of the terminal in the signal receiving process is counteracted. The method is especially suitable for scenes with wide coverage and multipath delay exceeding the cyclic prefix length, can significantly reduce inter-symbol interference, and improves the synchronization precision and overall demodulation performance of a terminal receiver.

Ultra-Wideband (UWB) technology is a wireless technology supporting the transmission of large amounts of digital data over short distances using coded impulses over a wide frequency spectrum with very low power. Enhanced link performance and functionality of such UWB systems is presented exploiting multiple directive antennas for spatially filtering undesired signals and increasing signal strength whilst circuit complexity is reduced by eliminating baluns in prior art solutions. Further enhancements support payloads with flexible encoding schemes, improved channel utilization, reduced processing logic, improved robustness in correlation techniques, versatile synchronisation techniques, improved ranging, as well as providing for improved inter-symbol interference tolerance and detection.

A receiver includes a partial response (PR) system that receives a received signal from a transmitter over a channel and equalize the received signal such that there is a controlled relationship between consecutive values of equalized received symbols and transmitted data transmitted by the transmitter. The receiver also includes a decision feed forward equalization (DFFE) system that receives partial response signals from the PR system and cancel at least one of pre-cursor intersymbol interference (ISI) or post-cursor ISI introduced by the channel.

The application discloses a computing system configured to measure a step response of a channel in an electronic device, determine a feedback voltage added to the channel by a decision feedback equalizer in response to detecting inter-symbol interference in a received symbol, and predict signal integrity of the channel based at least in part on the step response of the channel and the feedback voltage. The computing system may utilize the predicted signal integrity to determine a probability that a feedback voltage added to the channel by the decision feedback equalizer is wrong, and determine a signal integrity of the channel based at least in part on the step response of the channel, the feedback voltage, and a probability that the feedback voltage added to the channel by the decision feedback equalizer is wrong.

This invention provides a method for eliminating inter-symbol interference (ISI) and nonlinear distortion in a joint channel estimation system. The method includes system parameter settings, ultra-wideband channel estimation, construction of ISI and nonlinear distortion matrices, and least-squares estimation of the original signal. This method utilizes pilot signals to achieve ultra-wideband channel estimation. Subsequently, based on the channel estimation results, an iterative algorithm is used to construct the ISI and nonlinear distortion matrices. Based on these constructed matrices, the ISI and nonlinear distortion in the received signal are eliminated, achieving accurate estimation of the original signal, reducing the bit error rate of the communication system, and improving system performance.

The invention provides an uplink data transmission method and device and a storage medium, and relates to the technical field of communication, and the method comprises the steps: obtaining auxiliary information of a plurality of satellites; determining first timing advance (TA) corresponding to the plurality of satellites according to the auxiliary information of the plurality of satellites and the current TA calibration information of the plurality of satellites; and sending uplink data to the access network equipment through the plurality of satellites according to the first TA corresponding to the plurality of satellites. According to the uplink data transmission method and device and the storage medium provided by the invention, the uplink data sent by the terminal equipment to the access network equipment can be simultaneously received by the access network equipment, the inter-symbol interference of the uplink data is reduced, and the correctness of the access network equipment for demodulating the uplink data is improved.

The technologies described herein are directed towards aligning the downlink symbol timing boundaries of coordinated multi-point (CoMP) transmitting radio units, so that a user equipment receives transmitted signals from each cell at generally the same time. In a CoMP scenario, synchronized downlink transmissions from a connected cell and a cooperating cell are generally not received at the same time by a target user equipment because of different propagation distances from the transmitting radio units; such misalignment leads to performance degradation. By offsetting the downlink symbol timing boundaries relative to each other, a targeted user equipment receives symbols at the desired time boundary, resulting in constructive interference that improves and a cell's downlink throughput and / or coverage. Time alignment via offset symbol timing boundaries also eliminates inter-symbol interference. Modified scheduling can be used to ensure that downlink and uplink transmissions from the coordinated radio units do not interfere with one another.

The invention discloses an interference equalization method, device and equipment for multi-carrier modulation in a high-dynamic scene and a storage medium, and relates to the technical field of mobile communication, and the method comprises the steps: obtaining a time domain channel matrix of a time-frequency double-color dispersion channel, and determining an inversion core matrix in a minimum mean square error equalization matrix based on the time domain channel matrix; based on the sparsity structure of the inversion core matrix, decomposing the inversion core matrix to obtain a decomposition matrix; based on the time domain channel matrix, the inversion core matrix and the decomposition matrix, determining a multilayer linear equation set with minimum mean square error equalization; and solving the multi-layer linear equation set to obtain an equalization result. By means of the mode, the calculation complexity of the equalization process in the process of resisting inter-symbol interference and inter-carrier interference existing in multi-carrier modulation in a high dynamic scene is remarkably reduced, excellent performance is still kept under the extreme condition that no cyclic prefix exists or the length of the cyclic prefix is zero, and high scene adaptability and system practicability are embodied.

The embodiment of the application provides a method for determining timing advance, and a communication device, which are used for improving the precision of terminal calculating timing advance (TA) and solving the problem of inter-symbol interference (ISI). The method comprises the following steps: a first network device determines a first parameter according to a first time delay compensation value, wherein the first time delay compensation value is a time delay compensation made by the first network device for receiving a signal sent by a terminal, the first parameter is used for indicating a difference value between a round-trip time delay of a feeder link in a non-terrestrial network (NTN) and the first time delay compensation value, and the difference value is used for determining a TA used by the terminal for sending a signal; and the first network device sends the first parameter.

A method for reducing inter symbol interference (ISI) and inter carrier interference (ICI) in transmissions between a sender and a recipient within a wireless communication network. For at least one multicarrier symbol comprising a first subcarrier modulated with an original reference signal and multiplexed with a second subcarrier modulated with an original payload signal. The method includes applying a multiple symbol shift configuration on at least a second multicarrier symbol adjacent to the first multicarrier symbol by repeating the original reference signal and the original payload signal in the second multicarrier symbol on respective subcarriers and applying a linear phase shift to each repeated reference signal and payload signal. The same linear phase shift is used for both the repeated reference signal and the repeated payload signal.

The application relates to the technical field of multi-path data transmission, and discloses an electric energy meter reading system and method based on the Internet of Things, which comprises the following steps: dividing a target electric energy meter into a meter reading domain, establishing a power frequency phase synchronization reference and a double pilot subcarrier, controlling the electric energy meter to perform pilot loopback sampling, extracting pilot complex sampling values, calculating group time delay tail scheduling according to the pilot complex sampling values, and generating a multiplexed meter reading time slot table containing a guard interval and an uplink starting time; then, sending a downlink inquiry frame according to the scheduling sequence; freezing and sending data of the electric energy meter at a specified time; and finally, receiving, decoding and outputting a telemetry data set by the concentrator. The application can effectively avoid inter-symbol interference caused by group time delay tailing, and improve the meter reading success rate.

The invention discloses a frequency domain super-resolution reconstruction OFDM (Orthogonal Frequency Division Multiplexing) waveform distortion suppression method, and belongs to the field of wireless communication. The method solves the problems that an existing method is high in complexity, sensitive to channel conditions and poor in error rate performance. The method comprises the following steps: constructing an interpolation matrix at a receiving end, and carrying out weighted interpolation on a frequency domain receiving signal by utilizing adjacent spectral line weighting to generate an interpolated frequency domain signal; the method comprises the following steps of: deducing to obtain a time domain equivalent relation of interpolation processing of a transmitting end and a receiving end by combining the logic of performing frequency domain zero insertion on an original frequency domain signal by a transmitting end, further jointly estimating an interpolated channel, and designing an equalizer according to a minimum mean square error criterion to perform equalization processing on the interpolated frequency domain signal to complete data recovery. According to the method, the problem of inter-symbol interference caused by insufficient CP of a common OFDM system with insufficient cyclic prefixes is solved, inter-symbol interference and inter-subcarrier interference caused by insufficient cyclic prefixes can be effectively suppressed, and accurate demodulation data can be obtained. The method can be applied to the field of wireless communication.

The application discloses a pre-coding optimization method for a 6G-oriented MIMO-OTFS system, which is based on a maximum signal-to-noise ratio criterion and constraints the total power of a base station to save resources and achieve the purpose of designing an optimal pre-coder.The implementation steps are as follows: firstly, a channel matrix is determined according to a system model; secondly, a delay-Doppler domain input-output relationship is obtained; thirdly, a target function problem with a pre-coding matrix as a variable is established according to the input-output relationship; and finally, the Dinkelbach algorithm is used to convert the target function into a form of subtraction of auxiliary variables, fix a variable, convert the original non-convex optimization problem into a semi-definite programming (SDP) problem, and obtain an optimal pre-coding matrix.The optimal pre-coder designed in this way not only eliminates the inter-user interference, but also eliminates the inter-symbol interference of the same user.The communication performance between different users is effectively ensured through the design and optimization of the pre-coding matrix, and the bit error rate of the MIMO-OTFS system is further reduced.

Ultra-Wideband (UWB) technology is a wireless technology supporting the transmission of large amounts of digital data over short distances using coded impulses over a wide frequency spectrum with very low power. Enhanced link performance and functionality of such UWB systems is presented exploiting multiple directive antennas for spatially filtering undesired signals and increasing signal strength whilst circuit complexity is reduced by eliminating baluns in prior art solutions. Further enhancements support payloads with flexible encoding schemes, improved channel utilization, reduced processing logic, improved robustness in correlation techniques, versatile synchronization techniques, improved ranging, as well as providing for improved inter-symbol interference tolerance and detection.

The invention provides a training method of an end-to-end inter-symbol interference compensation model, an interference compensation method and equipment, and the method comprises the steps: inputting a training data sequence into a current end-to-end system model in a current iteration round, so as to enable a transmitting end processing module in the model to generate a simulation transmission signal, a channel module in the model transmits the simulation transmission signal to obtain a received complex symbol sequence, and a receiving end processing module performs inter-symbol interference compensation on the received complex symbol sequence and outputs interference compensation result data; determining target loss according to the interference compensation result data and optimizing model parameters to update the model; and if the model is converged at present, determining the transmitting end processing module and the receiving end processing module of the updated model as the model for performing inter-symbol interference compensation on the data sequence. According to the invention, global optimization of the super-Nyquist coherent optical transmission system can be realized, and inter-symbol interference can be effectively compensated.

The application discloses a method for determining timing advance and a terminal, and is used for providing a calculation mode of timing advance, improving the adaptability of different parameters of a satellite-ground communication scene, and avoiding the problems of excessive timing advance or introduction of inter-symbol interference due to improper experience value setting. The method comprises the following steps: determining the motion state of a satellite relative to a terminal; when the satellite is in a close state relative to the terminal, acquiring a last estimated Doppler frequency offset value, and determining the timing advance of a current time slot according to the last estimated Doppler frequency offset value.

A delay optimizer includes circuits for detecting delay between the received data and the received clock, such as in an integrated circuit having separate dies coupled to communication via an interconnect that includes a clock channel and a data channel. The electrical characteristics of the clock channel and the data channel (including on-chip buffers) may introduce significant differences in the delay between the received clock and the received data coupled with the effects of clock jitter, inter-symbol interference, and duty-cycle distortion that may introduce significant sampling errors in the sampled data. The delay optimizer operates to detect the delay and optimize a sampling clock in real-time and on a continuous basis using the difference between the data edge of the received data and the received clock edge to determine an optimal delay value to sample the received data to produce the sampled data with the desired very-low bit-error-rate (BER).

A device includes an amplifying device that when in operation transmits a data signal and a reference signal to a decision feedback equalizer (DFE) circuit. The amplifying device includes a variable gain amplifier (VGA) that when in operation generates the reference signal as having a predetermined gain relative to a received input signal and a continuous-time linear equalizer (CTLE) that operate to mitigate inter-symbol interference (ISI) on the data signal from a data stream comprising the data signal. The device further includes correction circuitry coupled to the amplifying device, wherein the correction circuitry when in operation mitigates variation in the predetermined gain of the VGA or variation in an output common-mode voltage of the VGA.

Systems and methods are described for generating and implementing pulse-shaping filters for efficient utilization of limited spectral resources in wireless communication systems. Wireless communication systems operating at high spectral efficiency conventionally use pulse shaping filters that rely on Nyquist waveforms for good main lobe performance with low inter-symbol interference (ISI) power. Conventional uses of non-Nyquist waveforms typically involve an orthogonalization process to convert those non-Nyquist waveforms to Nyquist waveforms for ISI free performance. Embodiments of pulse shaping filters described herein generate a non-Nyquist partial response (NNPR) transmit filter and / or matched receive filter based on applying a tunable second-weighted orthogonalization to a tunable first-weighted non-Nyquist waveform to obtain a pulse-shaping waveform with parametric control over throughput and power penalty.

A receiver includes: equalizer circuitry; clock and data recovery (CDR) circuitry; sampler circuitry; adaptation circuitry; and clock adjustment circuitry. The receiver is configured to: receive data via a channel; perform equalization operations on received data, the equalization operations resulting in equalization results; perform sampling operations responsive to the equalization results, the sampling operations resulting in data samples and error samples; perform adaptation operations responsive to the data samples and the error samples, the adaptation operations resulting in a clock adjustment control signal; and adjust a sampling clock signal relative to a CDR clock signal responsive to the clock adjustment control signal.

The invention discloses a high-speed signal testing system and method. Comprising a microcontroller, a programmable power supply module, a chip to be tested and an inter-symbol interference board, the microcontroller respectively configures the programmable power supply module and the chip to be tested according to the first type of configuration parameters; the programmable power supply module provides adaptive power supply for the chip to be tested according to a voltage parameter in the parameters; the chip to be tested combines a voltage configuration result, a binary code pattern parameter and an equalization parameter to generate a first high-speed sending signal, sends the first high-speed sending signal to the inter-symbol interference board, receives a first high-speed receiving signal fed back by the inter-symbol interference board, and transmits the two signals to the microcontroller; the inter-symbol interference board simulates transmission loss and inter-symbol interference of a real channel, and the microcontroller calculates bit error rate information according to the transmission loss and the inter-symbol interference, generates a digital eye diagram and displays the digital eye diagram on a visual interface. Through automatic configuration, non-contact testing and real channel interference simulation, the bit error rate and the visual digital eye diagram are output, and accurate verification of the basic transmission performance of the high-speed chip is assisted.

A technique for reducing inter-symbol interference, frequency offset, and phase offset in a demodulator of a wireless communications system includes integrating a Kalman filter-based phase-locked loop (PLL) and a Viterbi equalizer. The integrated Kalman filter-based PLL and Viterbi equalizer includes a Kalman filter-based PLL that provides a frequency or phase offset corrected signal to a modified Viterbi equalizer and receives a reference signal for use in determining phase error. In an embodiment, the reference signal is based on an instant decision of the modified Viterbi equalizer rather than waiting for an entire traceback length of time to receive a Maximum Likelihood Sequence Estimation (MLSE) equalized symbol for use as the reference symbol by the Kalman filter-based PLL.

The application discloses a one-code multi-stream transmission method based on random multiplexing and joint detection decoding, wherein original signals are subjected to random multiplexing at a transmitting end, so that signal energy is uniformly distributed on all fading branches; signals transmitted by the transmitting end are received at a receiving end, and an iterative process is performed by using a cascaded CD-OAMP detection decoding receiver or a joint CD-OAMP detection decoding receiver; a linear estimator of the CD-OAMP performs linear minimum mean square error estimation, a nonlinear estimator performs symbol-by-symbol demodulation, and iteration is performed until convergence, so that a decoding result removing inter-symbol interference is obtained. The application makes equivalent channels approximate AWGN channels by random multiplexing, so that a single AWGN code is still robust. Inter-symbol interference introduced by random multiplexing is eliminated by a CD-OAMP detector with low complexity and Bayesian optimality. Decoding information is fully utilized by joint decoding detection, so that signal estimation is more accurate.

The invention discloses an optical communication driven robot base station recharging method and system, particularly relates to the technical field of optical communication, and is used for solving the problem of unreliable visible light communication signal identification caused by automatic exposure adjustment and environment interference in a complex light environment in the prior art. An image sequence containing visible light communication signals and an automatic exposure parameter sequence are collected, a brightness value sequence of a candidate light source area is established, modulation signals are demodulated, a first candidate set is obtained through screening on the basis of inter-symbol interference characteristics, and a second candidate set is obtained through analyzing motion trail smoothness characteristics. And finally, determining a real base station communication light source by evaluating the inverse correlation between the modulation signal and the automatic exposure parameter sequence, and calculating the course adjustment amount of the robot according to the position change to realize accurate recharging.

The invention discloses an inter-symbol interference depth determination method and device, and a storage medium. The method comprises the following steps: performing transient simulation on a signal channel to obtain an impulse response; on the basis of the pulse response, generating a candidate truncation point on a time axis, and determining characteristic indexes, including accumulation energy determined by accumulating the intensity of the pulse response to the candidate truncation point, residual peak amplitude determined by the maximum response amplitude after the candidate truncation point, and residual peak amplitude determined by the maximum response amplitude after the candidate truncation point; the truncation error is determined based on the difference between the cumulative energy up to the candidate truncation point and the overall energy; determining a determination parameter of the characteristic index based on the target precision or the system specification; based on the characteristic indexes and the judgment parameters, the candidate truncation points meeting the judgment parameters serve as effective memory lengths and serve as target inter-symbol interference depths; and establishing a time window corresponding to the target inter-symbol interference depth, executing statistical convolution operation, and outputting a statistical analysis result. The method and the device have the technical effect of improving the accuracy and the efficiency of inter-symbol interference depth simulation.

The application discloses a compensation method for CDR channel asymmetry in a high-speed transmission system i and a decision error e i of a current received symbol, attempts to match a continuous received decision bit stream with a special bit sequence pattern to calculate inter-symbol interference ISI, and then uses the calculated inter-symbol interference ISI to compensate for the asymmetry of the channel The application provides a compensation method for CDR channel asymmetry in a high-speed transmission system, which is simple to implement, has a faster convergence speed and better performance.

The application discloses a method and device for determining an intersymbol interference depth and a storage medium. The method comprises: performing transient simulation on a signal channel to obtain an impulse response; generating a candidate truncation point on a time axis based on the impulse response and determining characteristic indexes, including: cumulative energy determined based on the strength of the impulse response accumulated to the candidate truncation point, residual peak amplitude determined based on the maximum response amplitude after the candidate truncation point, and truncation error determined based on the difference between the cumulative energy up to the candidate truncation point and the overall energy; determining a judgment parameter of the characteristic indexes based on a target accuracy or system specification; taking the candidate truncation point meeting the judgment parameter as an effective memory length and a target intersymbol interference depth based on the characteristic indexes and the judgment parameter; establishing a time window corresponding to the target intersymbol interference depth, performing a statistical convolution operation, and outputting a statistical analysis result. The application has the technical effects of improving the accuracy and efficiency of intersymbol interference depth simulation.

The application discloses a hardware link modeling method, wherein a total transfer function of a link is obtained through scattering parameters, a step response of the link is obtained through the transfer function, the response is stored in a lookup table, a jitter generation circuit is designed by using a hardware description language to obtain each jitter component injection value and then obtain a total jitter injection value, a link modeling circuit is designed by using the hardware description language to interpolate the step response with the total jitter injection value to complete total jitter injection and obtain a step response after jitter injection, a circuit for converting the step response into a pulse response is designed by using the hardware description language, and finally a pulse response after jitter injection is obtained to complete hardware circuit modeling of inter-symbol interference and jitter of the link. Hardware resource consumption of the application is far lower than that of a traditional algorithm.

The present invention discloses an apparatus for use by a coherent receiver, comprising means for: obtaining a first set of coefficients (A+) indicating a first adaptive filter (A) configured to reduce at least part of polarization mode dispersion in an equalizer of the coherent receiver and a second set of coefficients (w+) indicating a second adaptive filter (w) configured to reduce at least part of the inter-symbol interference in the equalizer of the coherent receiver, determining a first updated set of coefficients (A++) and a second updated set of coefficients (w++) based on the first set of coefficients (A+) and the second set of coefficients (w+), wherein the gains of the first updated set of coefficients (A++) have a predetermined level, and wherein, the output of the equalizer based on the first set of coefficients (A+) and the second set of coefficients (w+) is approximately same as the output of the equalizer based on the first updated set of coefficients (A++) and the second updated set of coefficients (w++), providing the first updated set of coefficients (A++) and the second updated set of coefficients (w++) to the first filter and the second filter respectively.

The invention discloses an ad hoc network duplex voice long-distance transmission method based on OFDM (Orthogonal Frequency Division Multiplexing), relates to the technical field of wireless communication, and effectively solves the contradiction of low spectrum efficiency and insufficient anti-interference capability of a traditional OFDM system in low-rate voice transmission through an adaptive subcarrier allocation and parameter optimization mechanism. The total bandwidth is dynamically divided into a voice dedicated subcarrier group and a data service subcarrier group, and a narrower subcarrier interval is adopted for a voice service to accurately match the bandwidth requirement of the voice service, so that the spectrum utilization rate is greatly improved on the premise of ensuring the voice quality, and the bandwidth of the voice service is greatly improved in the face of complex and changeable multipath interference in a riding environment. The cyclic prefix length is dynamically adjusted according to the channel maximum multipath delay estimated in real time, it is ensured that inter-symbol interference caused by multipath can be completely eliminated, frequency spectrum resource waste caused by a fixed long cyclic prefix is avoided, and intelligent linkage of the volume and the riding state is achieved.