10 results about "Symbol error rate" patented technology

The present application belongs to the technical field of wireless communication, and particularly relates to a multi-reflection device signal modulation and beamforming cooperation optimization method. The method of the present application mainly gives the modulation mode of the main system signal and the modulation order of the multi-reflection device, optimizes the signal constellation point of the reflection device and the beamforming to maximize the minimum Euclidean distance of the noise-free signal at the receiving end, thereby improving the symbol error rate performance of the main system and the Internet of Things communication. The scheme of the present application can be applied to the signal modulation of the main system and the Internet of Things system of any order, the scheme is simple to implement, and has strong application value.

A real-time oscilloscope comprises one or more interfaces for connecting to a device under test (DUT) to establish a communication channel between the oscilloscope and the DUT; one or more analog-to-digital converters (ADCs) for sampling a signal received from the DUT to convert the signal into a waveform; one or more processors for receiving and sampling a time-of-flight signal, including actual symbols, from the DUT to generate a time-of-flight waveform; resampling the time-of-flight waveform to locate samples in the center of each unit interval; and using a characterization of the communication channel, the samples in the center of each unit interval, a symbol constellation for the time-of-flight waveform, and a traceback length as inputs for a maximum likelihood sequence estimation (MLSE) procedure to estimate symbols in the time-of-flight waveform.and the estimated symbols are compared with the actual symbols to obtain a symbol error ratio.

The invention discloses a QAM wireless transmission oriented NRZ-TI-DACs system and a data processing method thereof, and belongs to the field of ultra-wideband signal generation, and the system comprises a digital signal processor, a phase shift clock, two paths of high-speed DACs, an auxiliary DAC and a superposition output circuit. The method comprises the following steps that: a high-frequency digital input sequence generates two paths of two-frequency-division digital sequences and one path of three-frequency-division compensation digital sequence which are subjected to compensation processing through an improved differential decomposition algorithm of a digital signal processor; the two paths of two-way frequency division digital sequences are respectively sent to two paths of high-speed DACs, and the compensation sequences are sent to an auxiliary DAC; two paths of same-frequency out-phase clocks are used for driving the corresponding DACs respectively; finally, the analog signals output by the three paths of DACs are superposed, and ultra-wideband analog signals are synthesized and output. Through cooperation of an algorithm and hardware, DAC output peak values are effectively limited, system power consumption is reduced, waveform stability is enhanced, lossless data conversion is realized, and low bit error rate and symbol error rate are ensured.

The invention discloses a string optimization method and system for a QC-QLDPC code and an SC-QLDPC code, and mainly solves the problem of low decoding performance caused by difficulty in suppressing a string structure from a topological structure level due to optimization only through a back-end decoding algorithm in the prior art. According to the implementation scheme, the method comprises the following steps: executing six-ring and eight-ring chord search for a QC-QLDPC code; and in a vector space of the QC-QLDPC code protograph matrix, a breadth-first search strategy is adopted to screen an optimal parameter combination satisfying quantum code structure constraints and having a minimized string number. The method comprises the following steps: for an SC-QLDPC code, dividing the SC-QLDPC code into a plurality of sub-blocks with a QC-QLDPC code structure, constructing a processing window, and executing string search in parallel to obtain the number of strings; a subblock-by-subblock iterative optimization strategy is adopted, and global constraint is applied to suppress a cross-subblock chorded short ring generated in a space coupling process, so that an SC-QLDPC code matrix parameter combination with the minimized number of chords is obtained under the condition that quantum code structure constraint conditions are met. According to the method, the frame error rate and symbol error rate performance of the two codes are effectively improved, and the method can be used for quantum error correction and quantum code string search and optimization of quantum chips and devices.

A real-time oscilloscope includes one or more ports to connect to a device under test (DUT) to establish a communication channel between the oscilloscope and the DUT, one or more analog-to-digital converters (ADCs) to sample a signal received from the DUT to convert the signal to a waveform, one or more processors to receive and sample a run-time signal including actual symbols from the DUT to create a run-time waveform, resample the run-time waveform to locate samples at a center of each unit interval, use a communication channel characterization, the samples at the center of each unit interval, a symbol constellation for the run-time waveform, and a configuration of a traceback length as inputs to a Most Likely Sequence Estimation (MLSE) process to estimate symbols in the run-time waveform, and compare the estimated symbols to the actual symbols to obtain a symbol error ratio.

The invention belongs to the technical field of backscatter communication, and discloses a high-performance space-time coding method and system for a four-antenna backscatter tag, and the method and system are better in energy harvesting (EH) performance. Only half of the antennas in each time slot are in an activated transmission state, the other half of the antennas are kept idle (in a matched state), and all the antennas participate in transmission in the activated state of traditional orthogonal space-time coding. As the energy harvesting efficiency of the antenna in the idle state is higher than that of the antenna in the activated state, the energy harvesting of the code in a linear energy harvesting model and a nonlinear energy harvesting model is obviously superior to that of an orthogonal space-time code, the autonomous endurance of the passive tag is facilitated, and the core problem of insufficient energy of the backscattering tag is solved. The symbol error rate (SER) is better; and energy efficiency and transmission performance are both considered.

The constellation optimization method for terahertz non-ideal channel based on deep learning belongs to the field of terahertz communication.The method of the present application is as follows: a transmitter based on DFT-s-OFDM modulation is designed to generate a transmission signal; a communication system model for terahertz non-ideal channel is established to obtain a received symbol sequence after the transmission signal is transmitted through the channel and processed by a receiver; a constellation optimization model based on a multi-layer neural network is constructed, a joint loss function containing three types of constraint terms is designed, adaptive optimization training is performed on constellation symbols, and an optimized constellation point sequence suitable for terahertz non-ideal channel is obtained; the optimized constellation points output by the multi-layer neural network are screened and constrained, projected and mapped to a standard QAM constellation to obtain a final constellation diagram satisfying the standard modulation format.The present application can reduce the symbol error rate under the condition of terahertz non-ideal channel, improve the robustness of the system to non-linear distortion and phase noise, and simultaneously consider power efficiency and implementation complexity.

The invention relates to the technical field of optical communication link regulation and control, in particular to an adaptive optimization method and system for optical transmission quality of a video stream. According to the method, the cross-layer mapping mechanism between the nonlinear characteristics of the optical physical layer and the coding parameters of the video application layer is constructed, so that the cross-phase modulation interference degree caused by the interaction of the multi-wavelength channels can be quantified in real time, and the directional decoupling adjustment of the chromaticity quantization step length is triggered when the channel degradation risk is perceived; noise interference of non-sensitive chrominance data is suppressed while brightness details are reserved, key reference nodes are accurately identified according to the reference frequency of a video frame in a time domain prediction sequence, and probability shaping modulation protection based on information entropy is implemented for high-value data. Limited light transmission energy is concentrated to guarantee the integrity of a core prediction frame, global error code diffusion caused by single frame damage is effectively restrained, and threshold dynamic closed-loop correction logic based on the real-time symbol error rate is matched.

The application provides a robust symbol-level precoding method against channel aging effect, wherein a cell base station uses channel state information affected by channel aging effect collected in uplink channel and user's sending symbol information to perform symbol-level precoding on sending symbols and transmit signals. The method proposes corresponding precoding schemes for two criteria of maximizing worst user's signal-to-interference-and-noise ratio and minimizing weighted mean square error between demodulation receiving signal and target constellation point. The precoding scheme design for maximizing worst user's signal-to-interference-and-noise ratio is converted into a fractional programming problem and solved, and the problem in the precoding scheme design for minimizing weighted mean square error is solved through an alternating optimization algorithm. The two schemes respectively improve user's signal-to-interference-and-noise ratio and reduce weighted mean square error between demodulation receiving signal and target constellation point while significantly reducing transmission symbol error rate.

The present application relates to the technical field of optical communication link regulation, in particular to a video stream optical transmission quality adaptive optimization method and system.In the present application, by constructing a cross-layer mapping mechanism between the optical physical layer nonlinear characteristics and the video application layer encoding parameters, the degree of cross-phase modulation interference caused by the interaction of multiple wavelength channels can be quantified in real time, and the directed decoupling adjustment of chroma quantization step size is triggered when the channel degradation risk is perceived, the noise interference of non-sensitive chroma data is suppressed while the brightness details are preserved, and the key reference nodes are accurately identified according to the frequency of video frames in the time domain prediction sequence, the probability shaping modulation protection based on information entropy is implemented for high value data, the limited optical transmission energy is concentrated on ensuring the integrity of the core prediction frame, the global error code diffusion caused by single frame damage is effectively curbed, and the threshold dynamic closed-loop correction logic based on real-time symbol error rate is matched.