36results about How to "Improve bit error rate performance" patented technology

According to the differential chaos shift keying modulator, demodulator and method based on reference modulation, reference modulation is achieved in a PPM modulation mode, the positions of reference signals at different time slots are used as one dimension of data transmission, extra information bits are mapped into specific indexes of active time slots, and therefore the accuracy of data transmission is improved. Therefore, under the condition of the same transmission energy, more bits can be transmitted in one symbol, thereby obtaining excellent bit error rate performance. Compared with the existing method under the code shift differential chaos shift keying system, the transmission rate and the energy efficiency of the system are improved. In general, according to the method, reference modulation is realized by adopting a PPM (Pulse Position Modulation) mode; the chaotic mapping is logistic mapping; according to the invention, the transmission rate and the energy efficiency of the CS-DCSK system are improved.

The invention relates to a self-adaptive CKF phase noise compensation method in a coherent light OFDM system. The method comprises the following steps of: estimating a phase noise value of each OFDM symbol at a signal receiving end through known pilot frequency information, performing first phase noise fitting by using a second-order Hermite interpolation function, performing pre-judgment and secondary symbol partitioning on a compensated signal, performing second phase noise fitting by using an updated second-order Hermite interpolation function, and performing phase noise fitting on the compensated signal. And finally, the residual phase noise is suppressed by using the characteristics that the adaptive CKF can adaptively update the process noise and reduce the estimation error. Simulation results show that the method can effectively compensate CPE and ICI phase noise, meanwhile, the tolerance of the CO-OFDM system to the laser line width is also improved, and the performance of the system is improved.

The invention discloses a ZP-OTFS staged weight regulation MRC signal detection method, which mainly solves the problem that the number of iterations is high due to a fixed weight coefficient in the existing MRC detection algorithm, and comprises the following steps: constructing a time delay-Doppler DD domain zero-filling orthogonal time-frequency-space ZP-OTFS sending signal, and carrying out signal domain transformation on the ZP-OTFS sending signal; to generate a time domain transmit signal suitable for wireless channel transmission; the receiving end reconstructs the time domain receiving signal into a time delay-time (DT) domain receiving signal; and then MRC detection based on staged weight regulation is carried out on the DT domain receiving signal to obtain a DD domain sending signal vector estimation value. According to the method, the weight coefficient is reasonably set in different iteration stages to gradually optimize the MRC detection process, the system operation complexity can be effectively reduced, better bit error rate performance is achieved under the same complexity, and the method can be used for a ZP-OTFS system in a high-speed moving scene.

The invention discloses an underwater CSK-OFDM modulation and detection method based on LED linear constraint, and the method comprises the steps: enabling a transmitter to map a data bit stream of a constellation diagram into a complex symbol stream, converting the complex symbol stream into a real number time domain sequence through an ACO-OFDM module, carrying out the LED amplitude limiting of the time domain sequence, and obtaining a time domain clipping sequence; transmitting the time domain clipping sequence in a UOWC channel through a corresponding LED, introducing symbol timing deviation and amplitude limiting noise into a frequency domain by a receiver, and processing the time domain clipping sequence by using an ACO-OFDM module again to obtain a received signal; under the maximum expectation framework, the probability from each alternative constellation diagram is calculated, symbol timing deviation and additive white Gaussian noise variance are estimated, a globally optimal solution is obtained, and a constellation diagram recognition result is output through maximum likelihood demodulation. According to the method, the linear range constraint of the LED and the complex environment under the UOWC scene are comprehensively considered.

The invention belongs to the technical field of wireless communication, and particularly relates to a multi-user symbiotic wireless communication channel estimation and signal detection method. According to the designed transmission frame structure, the main system sending symbol is recovered by estimating the combined channel containing the reflection device sending symbol, and then the multiplicative relationship between the main system sending symbol and the reflection device sending symbol is decoupled, so that the error rate performance of main system transmission and reflection device transmission is improved. The scheme provided by the invention is simple to implement and has very high application value.

A power amplifier nonlinear correction algorithm suitable for a broadband high-order modulation signal relates to the technical field of channel nonlinear equalization, and comprises the following steps: acquiring a baseband signal and carrying out synchronous preprocessing to generate a time sequence signal and a timing synchronization signal; generating a balanced input vector according to the time sequence signal and the timing synchronization signal; constructing an OS-ELM balancing unit for processing the balancing input vector and generating a balancing output result; after an equalization output result is processed by a buffer, an equalization output vector is extracted; a symbol decision unit is constructed and used for generating a symbol decision soft value according to the time sequence signal and the balanced output vector; constructing an online training unit, which is used for generating an online label vector according to the time sequence signal and the symbol decision soft value, and generating a hidden layer output matrix according to the time sequence signal and the balanced input vector; finally, combining the online label vector, the hidden layer output matrix and the hidden layer output matrix of the historical sample to generate a weight matrix; using the weight matrix to update an equalization output result; and the calculation complexity is low.

The application discloses a high-parallelism storage-computation integrated polar code decoding method based on coset decoding, and belongs to the technical field of channel coding and decoding. The method comprises the following steps: constructing an error pattern group and a check constraint subgroup; performing coset division on the error pattern group to obtain a set of mutually disjoint cosets; screening a limited number of minimum cosets based on the minimum Hamming weight of the cosets; and performing parallel decoding processing on the paths corresponding to the minimum cosets in the storage-computation integrated architecture. k The number of paths in the traditional multi-bit decoding is reduced from 2 to a preset number L through coset division, and the parallel execution of the likelihood information updating and the path metric calculation is realized in combination with the calculation-type storage array, so that the decoding performance is ensured, the calculation complexity and the hardware resource consumption are significantly reduced, and the decoding throughput and the energy efficiency are improved.

The invention discloses a parallel stepped convolutional code space coupling coding and decoding (PSCBCC) method and device, belongs to the technical field of channel coding, and is suitable for a large-bandwidth communication scene. According to the method, a frame of data is divided into multiple groups of sub-data, parallel convolutional coding of three paths of input of current sub-data, interleaved previous sub-data and an interleaved previous check sequence is realized by utilizing a parallel coding unit, a current check sequence is generated, and the sub-data and the check sequence are respectively reserved to different subsequent moments to form asymmetric coupling; and during decoding, a parallel decoding unit is matched with a coding structure, and a plurality of groups of log-likelihood ratios are input to realize iterative updating. The throughput rate is improved through parallel processing, the bit error rate performance is enhanced through asymmetric coupling, multi-code-rate adaptation is supported, and the performance is superior to that of existing BCC and 4G / 5G standard codes.

The invention provides a non-ground network system orthogonal transformation auxiliary OFDM (Orthogonal Frequency Division Multiplexing) modulation and demodulation method, and relates to the technical field of NTN (Network Temporary Network) communication. The method comprises the following steps: a transmitter encodes and modulates a data stream, and blocks a data symbol sequence; two-dimensional fast Fourier transform is adopted as an orthogonal transformation type, and a diffusion symbol block is obtained through orthogonal transformation and deblocked; normalizing the diffusion symbol sequence and inserting a pilot frequency, and then performing OFDM modulation and adding a cyclic prefix; the receiver performs symbol synchronization and frequency offset compensation on the received symbol sequence, and then removes the cyclic prefix and performs OFDM demodulation; extracting a pilot symbol from the demodulated data to realize channel equalization; extracting a diffusion symbol sequence; inverse two-dimensional fast Fourier transform is carried out; deblocking the data symbol blocks; and normalizing, demodulating and decoding the received data symbol sequence to obtain a received data stream. According to the invention, the bit error rate can be effectively reduced in the environment with ultralow signal-to-noise ratio, multipath depth fading and large Doppler frequency offset.

The present invention relates to the field of data storage technology, and in particular to a NAND flash memory dynamic write voltage method and device. The present invention discloses a NAND flash memory dynamic write voltage method and device, wherein the method comprises: constructing a cost function according to a high-order channel error rate, a low-order channel error rate and a minimum Hamming distance estimated by an LDPC code; taking the minimum function value of the cost function as an optimization target, taking the first programming voltage and the second programming voltage as independent variables, performing convex optimization calculation on the cost function, and outputting an optimal first programming voltage and an optimal second programming voltage, thereby solving the technical problem in the prior art that when a codeword is only stored in a high-order bit page or a low-order bit page, the overall bit error rate performance will be deteriorated if the existing write voltage method is continued to be used due to unequal high and low-order channel error rates, thereby improving the overall bit error rate performance of the NAND flash memory.

This invention discloses a signal detection method for an OTFS system based on an adaptive wavelet scattering convolutional neural network, comprising: converting the data symbols to be transmitted to the DD domain, and then obtaining an OTFS signal through an OTFS modulator; the OTFS signal reaching the receiver through a wireless channel; at the receiver, transforming the received signal back to the DD domain using an OTFS demodulator; extracting the real and imaginary signal matrices from the received OTFS signal, performing a three-layer wavelet scattering network transformation on these two matrices to obtain scattering feature coefficients for each layer, concatenating the scattering feature coefficients along the feature channel direction to reconstruct a high-dimensional feature matrix of the signal, and using it as the input to an adaptive wavelet convolutional neural network 2D-AWCNN to obtain the possible values ​​corresponding to each QAM symbol; and performing 16-QAM demodulation on the output of the adaptive wavelet convolutional neural network 2D-AWCNN using a demodulator to obtain the output bits used for signal detection.

The present invention discloses an underwater coherent superposition keying method and system combining Reedsor code with orbital angular momentum. The present invention uses a semiconductor laser as a light source, uses a beam splitter to generate four parallel light beams, and controls the optical switch in parallel with the encoded data to control the parallel light beams to generate vortex light beams with different orbital angular momentum states through a spatial light modulator. Based on the coherent superposition, a composite vortex light beam is generated. After being disturbed by the ocean turbulence channel, adaptive demodulation based on deep learning is realized at the receiving end, and then the original data is restored through a decoder. The modulation rate of the digital information of the present invention is no longer limited by the refresh rate of the spatial light modulator. The introduction of encoding and decoding can effectively improve the bit error rate performance of the system and increase the anti-interference ability of the system. The demodulation method based on the pre-trained neural network of the present invention improves the demodulation speed and accuracy of the system. The demodulation structure is very simple and reduces the system cost.

This invention discloses a fast pattern-coupled sparse Bayesian multi-user detection method, comprising the following steps: Step S1: Construct a large-scale IoT uplink system model, convert the multi-timeslot signal measurement model into a single measurement vector model, and assign a pattern-coupled Gaussian prior distribution to the sparse signal to be detected, initializing the hyperparameter set; Step S2: Based on variational inference, derive the relaxed evidence lower bound of the system's logarithmic marginal likelihood function; Step S3: Update the hyperparameter set using the variational expectation maximization method to maximize the relaxed evidence lower bound; Step S4: Determine whether the iteration termination condition is met. If it is, stop the iteration and output the recovered active user signal; otherwise, return to step S3. This invention effectively utilizes the adjacency correlation of each user's transmitted signal through a pattern coupling mechanism, significantly improving detection accuracy; and it can meet the requirements of real-time performance and high reliability in large-scale IoT scenarios.

The invention discloses a stepped convolutional code (HSCBCC) coding and decoding method and device for high-speed large-bandwidth data transmission, and belongs to the technical field of communication channel coding. According to the coding method, a frame of data is divided into a plurality of groups of sub-data, a convolutional code coder is adopted to code a combined sequence of current sub-data and previous specific sub-data and a previous specific check sequence subjected to interleaving processing, and a current check sequence is generated; respectively retaining the current sub-data and the verification sequence to different subsequent moments as input; the decoding method comprises the following steps: iteratively processing channel information and extrinsic information of the corresponding sub-data and the check sequence, and outputting a decoding result. According to the invention, an asymmetric double-coupling structure is adopted, the bit error rate performance is superior to that of an existing space coupling coding scheme under the same resource consumption, and the method is adaptive to a multi-code-rate scene and is suitable for the technical field of large-bandwidth wireless communication or optical fiber communication.

The invention discloses an incoherent authorization-free communication method, device and system for dual-mode information grouping, and belongs to the field of wireless communication, and the method comprises the following steps: incoherent information modulation: a signal transmitting end determines the information transmission mode of each group in a data frame, the position of an active information transmission block and the pilot frequency selected by the active block according to system configuration information and a bit to be transmitted, the information transmission mode comprises a high-low density transmission mode and a low-density transmission mode, and the number of active data blocks in groups in the high-density transmission mode is large; energy estimation: the receiving end estimates the energy of the transmitted signal by adopting a block coordinate descent algorithm based on pruning operation; active sending end detection: setting an adaptive quantity threshold value based on an energy estimation vector estimation result, and determining an active sending end according to an energy threshold value and the number of active data blocks; and information bit recovery: carrying out information bit recovery on the active sending end according to the estimation result of the energy estimation vector and the configuration information. According to the invention, the transmission rate can be improved without increasing pilot frequency resources.

An uplink multiple access transmission method of a multi-user orthogonal time-frequency space system comprises the following steps: mapping transmitting signals of users into orthogonal amplitude modulation symbols, multiplexing information symbols along a whole time delay axis with corresponding Doppler indexes for different users to obtain an indicator matrix of Doppler division multiple access, and in addition, obtaining time domain transmitting signals; processing the time domain receiving signal, and combining an indicator matrix of Doppler division multiple access to obtain a receiving signal of a DD domain of the DoDMA based on OTFS modulation; a serial interference elimination method is applied to received signals of a DD domain of DoDMA based on OTFS modulation at a base station, signals of all users are judged one by one according to the size of signal power, the achievable rates of all the users are obtained according to the mutual information theorem and the property of trace operation, and uplink multiple access transmission is carried out based on the achievable rates of all the users. According to the method, the influence of high Doppler frequency shift and interference among multiple users caused by rapid movement can be solved, and the transmission rate and the bit error rate performance are improved.

The application provides a LoRa modulation method based on three-dimensional constellation assistance, and belongs to the field of signal processing. By dividing the information bit stream into a frequency index bit stream and a constellation mapping bit stream, and respectively using them to generate a three-dimensional orthogonal LoRa base signal and perform three-dimensional constellation mapping, a new three-dimensional signal space is constructed for joint modulation. This core design enables more information bits to be transmitted simultaneously within a symbol period, significantly improving the data rate of the system. More importantly, compared with the traditional two-dimensional constellation, the three-dimensional constellation can provide a larger minimum Euclidean distance between symbols under the same modulation order. This fundamental improvement in geometric characteristics directly translates into stronger anti-interference capability and lower bit error rate of the signal in noise and fading channels. Therefore, the method effectively improves the spectral efficiency of the LoRa system while enhancing its transmission reliability, achieving a synergistic improvement in performance.

The present invention discloses a differential chaotic shift keying modulator, demodulator and method based on reference modulation, which realizes reference modulation by PPM modulation, and uses the position of reference signals in different time slots as a dimension of data transmission, so that additional information bits are mapped to specific indexes of active time slots. Therefore, more bits can be transmitted in one symbol under the same transmission energy, thereby obtaining superior bit error rate performance. Compared with the existing code-shift differential chaotic shift keying system method, the present invention improves the transmission rate and energy efficiency of the system. In general, the method realizes reference modulation by PPM modulation; the chaotic mapping is logistic mapping; the present invention improves the transmission rate and energy efficiency of the CS-DCSK system.

The invention belongs to the technical field of data link communication, and particularly discloses a Turbo coding device and decoding device based on an FPGA, and the FPGA of the Turbo coding device is provided with a main control module, a first memory, an interleaving module, a first RSC coding module, a second RSC coding module and a puncturing multiplexing module. A sequence separation module, an iterative decoding module and a main control module are configured on an FPGA (Field Programmable Gate Array) of the Turbo decoding equipment. According to the invention, turbo coding and decoding can be realized based on the FPGA, and by adopting the turbo coding and decoding equipment provided by the invention, the information processing capability of the system can be improved, and meanwhile, the system can be ensured to obtain better bit error rate performance; according to the method, the structure is simple, hardware description language Verilog language can be used, a hardware environment can be built for implementation, and the practicability is high.

The invention discloses a channel code pattern optimization method based on Gaussian weighted hybrid approximate density evolution, and relates to the technical field of wireless communication. The method includes constructing a modulation system. A delay module is introduced at a sending end, joint information source and channel decoding is carried out at a receiving end, and likelihood information of delay bits is fed back to a demodulator. Likelihood information probability distribution output by all sub-channels of the system is obtained, and it is confirmed that the distribution does not meet symmetric Gaussian distribution. Based on the characteristics of likelihood information output by each sub-channel under the condition of a single constellation point, decoding convergence performance is analyzed by adopting a density evolutionary algorithm of Gaussian weighted hybrid approximation, and Gaussian weighted hybrid approximation distribution of the likelihood information output by each sub-channel is obtained. And searching and optimizing by using a density evolutionary algorithm based on Gaussian weighted hybrid approximation as an analysis tool to obtain an optimized channel code basis matrix. And constructing a channel encoder by using the optimized channel code basis matrix to replace the original channel code so as to improve the bit error rate performance of the system in the waterfall region.

The invention discloses an OCDM transmission method based on symbol-level precoding, and belongs to the technical field of communication. According to the method, on the basis of OCDM system transmission under a multipath channel, an optimization problem of power minimization is designed, an equivalent ZF precoding matrix for the OCDM system is obtained, and a corresponding SLP algorithm based on non-negative least squares is designed, so that the sending power is reduced, and a final sending signal is obtained. According to the method disclosed by the invention, symbol-level precoding is combined into the OCDM system, the interference signal is manipulated by the SLP so as to be favorably superposed at the signal receiving position, and the OCDM system is assisted to obtain the final sending signal, so that the degree of freedom of a communication system and the energy efficiency of the system are effectively improved, and the error rate performance of the system is fully improved.

The invention belongs to the technical field of wireless communication, and particularly relates to an environment backscatter communication transmission method. According to the invention, a sending symbol of a reflection device at each moment is set as a constellation point symbol, antennas of the reflection device of the Internet of Things are divided into two groups, and two continuous symbol transmission moments of the reflection device of the Internet of Things are set as a moment period; sending symbols of the first group of antennas and the second group of antennas are respectively in a complex conjugate form of sending signals of each other at two transmission moments, correspondingly, receiving signals of one moment period need to be processed at the same time when a receiving end demodulates, and finally, the receiving signals at the two moments are processed at the same time to obtain the receiving signals. Compared with a traditional transmission method, the method has the advantages that the bit error rate performance is remarkably improved, and particularly, a better diversity gain effect is shown in a backscattering link.

The invention discloses a three-dimensional low-complexity probabilistic shaping coding method for a PDM optical communication system, and the method comprises the steps: carrying out the 3D-QPSK constellation mapping of a high-power signal, and obtaining a processed high-power signal. And after weight-driven bit inversion processing is carried out on the low-power signal, 3D-8QAM constellation mapping is carried out, and a processed low-power signal is obtained. And carrying out PDM superposition on the processed high-power signal and the processed low-power signal to obtain a 3D-32QAM signal after probability shaping. The PDM and WDBR-PS technologies are applied to the three-dimensional constellation, the WDBR technology only needs to be operated in the bit dimension, and the hardware burden of a PDM system sensitive to resource allocation cannot be increased. Meanwhile, by expanding a two-dimensional constellation to a three-dimensional constellation, not only is the PAPR of the OFDM signal effectively reduced, but also the problem that the bit error rate is suddenly increased due to the fact that the distance between constellation points is too small in high-order modulation is avoided.

The present invention provides a BPL decoding algorithm for a CRC-LDPC-Polar cascade system. In the cascade system, a cyclic redundancy check and an inverse-coded codeword check of a polarization code generation matrix are used as early stopping criteria, and a BP decoding algorithm is first used. If the check fails, a BPL decoding algorithm is then used, and the decoding complexity of the BPL decoding algorithm in the cascade code is reduced by reducing the number of iterations of the cascade code decoding algorithm. In addition, a new factor graph selection method is proposed for the BPL decoding algorithm of the polarization code. The factor graph selection method uses the mean of the polarization channel log-likelihood ratio in the polarization code Gaussian approximation construction method to select L decoding factor graphs of the BPL decoding algorithm, so that the BPL decoding algorithm of the cascade system can also have better error performance when the list size L is small.

An uplink multiple access transmission method for a multi-user orthogonal time-frequency-space system includes: mapping a user's transmission signal into an orthogonal amplitude modulation symbol, multiplexing information symbols along the entire delay axis with corresponding Doppler indexes for different users, obtaining an indicator matrix of Doppler division multiple access, and obtaining a time domain transmission signal; processing the time domain received signal, and combining the indicator matrix of Doppler division multiple access to obtain a received signal of the DD domain of DoDMA based on OTFS modulation; applying a serial interference elimination method to the received signal of the DD domain of DoDMA based on OTFS modulation at the base station, judging the signal of each user one by one according to the size of the signal power, and then obtaining the achievable rate of each user by the mutual information theorem and the properties of the trace operation, and performing uplink multiple access transmission based on the achievable rate of each user. The present invention can solve the influence of high Doppler frequency shift and interference between multiple users caused by rapid movement, and improve the transmission rate and bit error rate performance.

The invention discloses a symbol-level precoding method based on wide linear processing, which comprises the following steps that: a base station obtains channel state information, and obtains a zero-forcing precoding matrix of the wide linear processing according to the channel state information; optimizing the disturbance variable, pre-coding each symbol in the transmission frame according to the optimized disturbance variable, and obtaining an optimal disturbance variable by minimizing the sending power; and under the optimal disturbance variable, a final sending signal is obtained in combination with the zero-forcing precoding matrix subjected to wide linear processing. According to the method, wide linear processing and symbol-level precoding are combined, the degree of freedom of a communication system can be improved, the effect of non-strict phase rotation constructive interference is generated, the sending power of the system is greatly reduced, and the bit error rate performance of the system is improved.

This application discloses a detection and decoding method and related equipment based on SCMA, relating to the field of communication technology. The SCMA-based detection and decoding method includes: receiving symbol sequence data corresponding to multiple users; iteratively decoding and detecting the symbol sequence data using a preset expectation propagation algorithm and a soft-output decoder; and outputting bit sequence information after reaching a preset stopping condition. The symbol sequence data includes multiple variable nodes and multiple functional nodes, which are iteratively updated based on prior information. This application reduces the bit error rate during data transmission.

The invention relates to the technical field of channel coding and decoding, and discloses a coding and decoding method and device for high-speed large-bandwidth data transmission. According to the coding method, a data frame is divided into multiple groups of sub-data, each group of sub-data and a plurality of adjacent groups of sub-data are merged and interleaved and then coded to generate a check sequence, and a code word containing the sub-data and the check sequence is output; according to the decoding method, iterative decoding is carried out on code words generated by encoding, related log-likelihood ratios are input, updating information is output through a convolutional code decoder, and a preset iteration sequence is adopted until decoding is completed. According to the invention, the coding structure is simplified, the hardware implementation complexity is reduced, the excellent bit error rate performance is maintained, the adaptability is high, and the method is suitable for a large-bandwidth communication scene.

The invention relates to a method for suppressing phase noise by a projection histogram in a coherent light OFDM (Orthogonal Frequency Division Multiplexing) system. According to the method, a cyclic prefix is linearly processed to reduce the power of inter-carrier interference (ICI), and phase noise is preliminarily suppressed; the method comprises the following steps of: firstly, obtaining rough estimation of phase noise by using a small amount of pilot frequency, further suppressing the phase noise by using pseudo pilot frequency assistance, and finally compensating the phase noise by using a projection histogram twice so as to improve time resolution and suppression precision. Simulation results show that under 16-order quadrature amplitude modulation (16QAM), when the laser line width is 100 kHz, the compensation effect of the algorithm is improved compared with that of a traditional projection histogram, and the frequency spectrum utilization rate is effectively improved.

The invention relates to a chaos shift keying modulation and demodulation method based on time diversity and full-carrier label index difference, the method is suitable for various channels, especially suitable for power line transmission channels, and the method is mainly summarized as follows: a modulator transmits reference information or modulation information for multiple times at different moments by adopting a time diversity technology, and the time diversity technology is used as a reference signal; information carriers except a reference carrier are divided into two types of carriers which are activated in sequence by using index bits, and binary bits are distinguished by transmitting different modulation signals at odd and even moments. A demodulator averages signals at different moments on a reference carrier to obtain a reference signal and averages odd and even moments of an information carrier to obtain signals transmitted at the odd and even moments of each carrier, and each information carrier firstly distinguishes a first activated carrier and a second activated carrier according to different signals transmitted at the odd and even moments so as to recover mapping bits; and then corresponding modulation bits are respectively demodulated on the first activation carrier and the second activation carrier. According to the invention, the anti-noise performance and the transmission rate of the system are improved.