124 results about "Intersymbol interference" patented technology

The invention provides a downlink data transmission method, device and system for laser fiber power supply application, and the method comprises the steps: carrying out the differential coding of downlink data to be transmitted through a transmitting end, and obtaining a data bit sequence; mapping the data bit sequence into a modulation symbol sequence by adopting a single-carrier phase modulation mode; performing digital-to-analog conversion on the modulation symbol sequence to obtain an analog signal; and outputting downlink energy and downlink data through an energy optical fiber according to the analog signal. According to the invention, the signal frequency spectrum is moved to be far away from the direct current frequency through differential coding and single carrier phase modulation, so that the interference of direct current laser energy on signal detection is minimized, the signal-to-noise ratio is improved, the inter-symbol interference is reduced, and a receiving end is ensured to have enough signal-to-noise ratio to reliably detect data.

The present invention provides a new pilot pattern and channel estimation method involving such pilot for mmWave OTFS systems in high mobility scenarios with non-ideal power amplifier, which is applicable in the fifth generation (5G) and beyond networks. The pilot pattern for communication signal in wireless communications involving mmWave systems with non-ideal power amplifier comprises signal including a pilot signal element, information-bearing symbol and zero as guard, wherein, position of pilot and guard are arranged to combat the effect of inter symbol interference (ISI) from nonlinear impairment of the power amplifier for accurate channel estimation.

Embodiments of this application provide a timing advance determining method and a communication apparatus, to improve precision of calculating a timing advance (Timing Advance, TA) by a terminal, and reduce inter-symbol interference (Inter-Symbol Interference, ISI). The method includes: A first network device determines a first parameter based on a first delay compensation value, where the first delay compensation value is delay compensation made by the first network device for receiving a signal sent by a terminal, the first parameter indicates a difference between a round-trip delay of a feeder link in a non-terrestrial network NTN and the first delay compensation value, and the difference is used to determine a TA used by the terminal for signal sending; and the first network device sends the first parameter.

Co-channel beacon transmissions are provided with at least one of spectral redundancy and temporal redundancy. A receiver produces a snapshot of a superposition of received co-channel beacon transmissions. Subcarrier demodulation, code nulling, or a Class-C linear minimum-mean-square error (MMSE) operation separates multiples ones of the co-channel beacon transmissions or eliminates inter-symbol interference and inter-subcarrier interference in the snapshot. Receiver operations can be performed at a network user, a network node, or a network operations center.

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 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.

The invention discloses an industrial multi-protocol communication gateway adaptive adaptation method and system, and relates to the technical field of industrial communication, and the method comprises the following steps: deploying a communication performance collection engine and a physical environment collection engine on a system in parallel, capturing a key performance index KPIs in real time, capturing a physical layer signal reflecting an electromagnetic activity state in a case, and transmitting the physical layer signal to a server; generating a real-time data stream with a timestamp; according to the method, a communication performance acquisition engine and a physical environment acquisition engine are deployed in parallel, key performance indexes KPIs are acquired, physical layer signals are captured, and a multi-dimensional associated communication-electromagnetic combined baseline model is established to sense the dynamic electromagnetic environment in the baseline model; a hidden fault of inter-symbol interference (ISI) caused by internal electromagnetic coupling can be accurately identified and quantified, a communication logic error and a physical layer electromagnetic phenomenon are accurately associated on a timeline, and accurate positioning of an interference source is realized.

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.

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 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 present invention relates to the field of wireless communications, and in particular to a method for adaptively configuring subcarriers and subsymbols in underwater acoustic generalized frequency division multiplexing communications. The purpose of the present invention is to solve the problem that the inter-carrier interference and inter-symbol interference of the GFDM system in underwater acoustic communications are too high due to the multipath effect, resulting in low accuracy of channel estimation and low communication quality. After selecting the optimal configuration, the method of the present invention can significantly improve the performance of the GFDM communication system in the underwater acoustic channel. By accurately analyzing and calculating the energy of inter-subcarrier interference and inter-subsymbol interference, the optimal configuration scheme based on minimizing interference energy is selected. This scheme not only makes full use of the flexible data block structure of GFDM, but also combines interference elimination technology to enable the system to perform better in the underwater acoustic multipath channel, thereby improving the accuracy of channel estimation and communication quality.

The present application provides a communication method and a related device. In the method, a first device determines a symbol group and sends the symbol group. The symbol group comprises a first cyclic prefix (CP), N time domain symbols and M second CPs; the N time domain symbols comprise M time domain symbols; each of the M time domain symbols is preceded by a second CP; the duration of the first CP is related to a first difference; the first difference is the difference between a preset duration and the total duration of the M second CPs; N is a positive integer greater than 1, and M is a positive integer greater than 0 and less than or equal to N. On the basis of the above solution, by adding a second CP before at least one symbol in the symbol group and defining the relationship between the second CPs before some symbols in the symbol group and the first CP before the first symbol, inter-symbol interference between symbol groups corresponding to different devices can be reduced, thereby enhancing orthogonality.

The invention relates to a communication system based on combination of deep joint source channel coding and OFDM (Orthogonal Frequency Division Multiplexing), belongs to the technical field of communication, and aims to improve the performance of the communication system. Serial / parallel conversion: dispersing the high-speed serial data to a plurality of subcarriers; iFFT conversion: realizing conversion from a frequency domain to a time domain; parallel / serial conversion: normalizing a time domain signal; adding a cyclic prefix to resist inter-symbol interference; d / A conversion: analog channel transmission is adapted; a / D conversion: digitally receiving the signal; removing a cyclic prefix; restoring the time domain signal; serial / parallel conversion: preparing for subsequent processing; carrying out FFT (Fast Fourier Transform); balancing: correcting channel distortion; parallel / serial conversion: recovering a serial form; and decoding: restoring the original information. According to the method, the two are effectively combined through the complete process, and the communication system performance is improved.

The application provides an OFDM underwater acoustic communication method based on a pseudo-random noise sequence, compared with existing TDS-OFDM and DPN-OFDM, due to the existence of CP in the PN-CPOFDM frame structure design, the influence of inter-symbol interference (ICI) on OFDM symbols is greatly weakened, therefore, the bit error rate performance of the PN-CPOFDM is superior to that of TDS / DPN-OFDM; the application simulates an actual underwater acoustic channel by using BELLHOP underwater acoustic channel simulation software, under the condition of a lower signal-to-noise ratio, the bit error rate performance of DPN-OFDM is equivalent to that of TDS-OFDM, when the signal-to-noise ratio is larger, the bit error rate performance of DPN-OFDM is superior to that of TDS-OFDM, and the bit error rate performance of the modulation scheme is improved with the increase of the signal-to-noise ratio, and the bit error rate performance of the modulation scheme is always superior to that of the former two modulation technologies, which further verifies the performance of the technical scheme.

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.

Embodiments of the present application relate to the technical field of communications, and provide a symbol processing method and a communication apparatus. The method is applied to a communication apparatus, and comprises: generating a first time slot, which comprises a plurality of symbols, wherein the plurality of symbols comprise a first symbol and a second symbol which are adjacent in a time domain, the first symbol and the second symbol respectively comprise a first symbol component and a second symbol component, and the two symbol components are the same; and sending the first time slot. Specifically, a network device sends first indication information and second indication information, which are respectively an equivalent cyclic prefix of the first symbol and a correlation quantity of the first symbol component, a terminal device receives the first indication information and the second indication information, and the network device generates and sends a first time slot; or a network device sends first indication information and second indication information, and a terminal device receives the first indication information and the second indication information, and then generates and sends a first time slot. The length of the equivalent cyclic prefix of the first symbol is greater than or equal to the length of a maximum multipath delay, so that cyclic convolution recovery can be achieved, thereby avoiding inter-symbol interference.

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.

A digital signal processing (DSP)-based serializer-deserializer (SERDES) includes a first filter configured to mitigate inter-symbol interference (ISI) attributed to dispersion associated with a long-reach transmission medium. The SERDES includes a second filter configured to shape the ISI. The SERDES includes also includes a third filter coupled in parallel with the second filter and configured to reduce ISI attributed to reflections associated to both near-zero delays and long delays.

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.

The invention discloses an information configuration method, a terminal and network side equipment, and belongs to the field of communication, and the information configuration method comprises the steps that the terminal receives first configuration information; wherein the first configuration information is used for configuring at least one of the following items: at least one first time unit type corresponding to at least one first time unit, and a combination mode of the at least one first time unit type; any one of the at least one first time unit type comprises any one of the following items: a cyclic prefix (CP) type or a CP length. According to the method, the flexibility of the time domain format of at least one first time unit can be improved, that is, the requirements of different transmission data, application scenarios or terminal types on CP types or CP lengths can be met, so that inter-symbol interference caused by channel delay extension or time-frequency offset synchronization can be reduced, and the user experience can be improved. And the problem of low resource efficiency caused by the cyclic prefix can be reduced.

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 present invention discloses an underwater acoustic orthogonal frequency division multiplexing secure communication method. The multiple transmit time reversal pre-filtering at the transmitter focuses the energy of the legitimate channel on the main path, shortening the channel of the cooperating party, while the eavesdropper still exhibits severe multipath characteristics. An orthogonal frequency division multiplexing signal with a short cyclic prefix smaller than the channel delay spread is transmitted, causing severe inter-symbol interference and inter-carrier interference to the eavesdropper. At the legitimate receiver, an interference cancellation-decision feedback equalizer is used to eliminate the residual interference of the cooperating party, improving the quality of the communication link of the cooperating party. Moreover, the secrecy capacity expression of the proposed method is given to evaluate the security performance of the system. The present invention is suitable for the underwater acoustic environment and has good performance in the long-delay frequency-selective underwater acoustic channel. When the location and channel information of the eavesdropper are both unknown, a considerable secrecy rate is obtained without the assistance of artificial noise.

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 present invention discloses a jitter measurement method combining time domain, frequency domain and statistical domain in a digital oscilloscope. First, the digital oscilloscope collects a long series of continuous signals and forwards the sampled data to a host computer. Then, each jump moment of the signal to be measured is found. Then, a software phase-locked loop is used to recover the reference edge moment according to the jump moment of the signal to be measured. Then, the jump moment of the signal to be measured is subtracted from the reference jump moment to obtain a set of time interval error sequences. Finally, based on this sequence, the jitter is analyzed and processed from multiple information domains to obtain the magnitude of the overall jitter, deterministic jitter, random jitter, periodic jitter, data correlation jitter, intersymbol interference and duty cycle distortion.

The invention relates to an efficient architecture for long arrival SERDES based on high performance DSP. A digital signal processing (DSP)-based serializer-deserializer (SERDES) includes a first filter configured to mitigate inter-symbol interference (ISI) due to dispersion associated with a long arrival transmission medium. In some embodiments, the SERDES includes a second filter configured to shape the ISI. The SERDES also includes a third filter coupled in parallel with the second filter and configured to reduce ISI due to reflections associated with both near zero delay and long delay.

This invention discloses a method for simplifying coherent DSP. A pilot signal (PT) is inserted outside the spectrum band of each dual-polarization signal at the transmitter. The receiver extracts the pilot signal through low-pass filtering. Frequency offset, phase noise, and polarization rotation are then estimated and compensated. A simple PAM equalization algorithm or a real 2x2 multiple-input, multiple-output (MIMO) equalization algorithm is then used to eliminate intersymbol interference (ISI), simplifying the coherent DSP. This method achieves not only fast polarization tracking capabilities and low complexity, but also low power consumption.