77 results about "Minimum mean square error" patented technology

The invention relates to the technical field of wireless communication, and discloses a compensation method for electronic radio frequency communication. According to the compensation method for the electronic radio frequency communication, the radio frequency signal and the channel state information are acquired, the original data set is generated, and the preprocessing steps of denoising, signal amplitude correction, phase correction and the like are performed, so that the data quality is improved, accurate parameter evaluation is performed by adopting the minimum mean square error, the accuracy of channel characteristic parameters is ensured, and the communication quality is improved. A mathematical model constructed based on the parameters enables calculation of compensation parameter gain and phase deviation to be more accurate, so that attenuation and distortion caused by signal propagation in a channel are effectively compensated, and finally, quality evaluation is carried out on the bit error rate and the signal-to-noise ratio of the compensated signal, so that the compensation effectiveness is ensured, and the signal quality is improved. And if the compensation is invalid, the calculation can be returned in real time for recalculation, so that the quality of the whole signal is improved.

The invention relates to the technical field of communication, and discloses a network communication chip signal interference suppression processing method. The method comprises the following steps: acquiring a local oscillator phase jitter sequence in real time through an on-chip phase noise monitoring unit; estimating Doppler frequency shift and channel coherence time based on the sequence; dynamically adjusting the closed-loop bandwidth of the phase-locked loop; and generating a phase compensation signal, and performing time-varying channel minimum mean square error equalization in combination with a received baseband signal to eliminate inter-symbol interference. The system integrates a phase noise monitoring function module, a channel parameter estimation function module, a phase-locked loop bandwidth regulation function module, a phase compensation generation function module and an interference joint elimination function module. By means of dynamic bandwidth reconstruction and high-precision phase compensation, the bit error rate under high-speed movement is remarkably reduced, the 5G millimeter wave communication standard requirement is met, and the method has the advantages of being achieved on a whole chip, low in delay and high in robustness.

The invention provides an intelligent metasurface enabled cellular-free large-scale MIMO (Multiple Input Multiple Output) network resource efficiency optimization method. The method comprises the following steps: establishing an intelligent metasurface enabled cellular-free large-scale MIMO network model under a Rician fading channel; based on the cellular-free large-scale MIMO network model, performing channel estimation by using a linear minimum mean square error method; based on the cellular-free large-scale MIMO network model, constructing a resource efficiency closed expression when a maximum ratio merging receiving scheme is used; constructing an optimization problem formula for maximizing the network resource efficiency according to the resource efficiency closed expression; and according to the optimization problem expression, designing an optimization method for cooperatively controlling a user power control coefficient and intelligent metasurface phase shift. The spectrum efficiency and the energy efficiency of the intelligent metasurface energized cellular-free large-scale MIMO network are improved, the compromise between the spectrum efficiency and the energy efficiency is effectively realized, the optimization of the network performance is realized, and an important theoretical support is provided for the development of a 6G Internet of Things network.

The invention discloses a magnetic anomaly data de-noising method and de-noising system based on step-by-step U-Net, and relates to the technical field of geophysical exploration, and the method comprises the steps: carrying out the forward modeling calculation based on a magnetic anomaly model in a simulation region, and obtaining a synthetic magnetic anomaly data set; a U-Net step-by-step denoising network model is constructed; designing a self-adaptive multi-stage training mechanism based on mean square error minimization; training the U-Net step-by-step denoising network model through the training set, taking parameters of the U-Net step-by-step denoising network model as initial weights, and performing fine tuning on the U-Net step-by-step denoising network model by utilizing supervised learning; the verification set is used for verifying the effect, and the effectiveness of the whole step-by-step denoising network model is verified according to the prediction effect of the test set; a forward noise adding process and a reverse noise removing process are designed, network behaviors are automatically adjusted according to noise steps, the problems of high training cost and poor performance when a deep learning model processes colored noise are effectively solved, and the problem of low signal-to-noise ratio is better solved.

The invention relates to the technical field of agricultural machinery load control, in particular to a corn harvester operation load control system and method, and the system comprises a power extraction module, a speed regulation and control module, a trend analysis module, a parameter optimization module and a load closed-loop module. According to the method, frequency characteristics are extracted in a periodic and segmented mode through header power signals, load dynamic sensing is carried out, advancing speed adjustment is more real-time and prospective, response sensitivity and stability are improved in combination with PID control, equipment stably operates at multiple crop densities and plots, the torque increment of a main shaft is monitored in real time, and wavelet transformation multi-scale analysis is carried out; load fluctuation fine-grained identification is carried out, a roller gap and power output are dynamically adjusted to optimize parameters with a minimum mean square error, frequency and torque characteristic closed-loop comparison is constructed, control self-matching and continuous self-adjustment are carried out, error minimization and trend tracking feedback are fused, the intelligence of the harvester is enhanced, and load sudden change performance fluctuation and energy consumption loss are reduced.

The invention belongs to the technical field of laser vibration measurement, and provides a self-focusing laser Doppler vibration measurement method and system capable of resisting self-vibration of an optical fiber, and the method comprises the steps: adding a compensation light path which is used for sensing and generating reference light which is equal to an interference signal in amplitude and is opposite to the interference signal in real time in a Doppler vibration measurement light path, and taking the minimum mean square error as a self-adaptive matching criterion; interference phases obtained by synchronous demodulation of the compensation light path and the main light path are subjected to adaptive matching and cancellation in amplitude and phase dimensions, residual errors of vibration of the vibration measurement system and other environmental interferences are suppressed below noise of the vibration measurement system, and the purpose of balancing and weakening optical fiber vibration interferences in an instrument is achieved. The influence of the vibration factor of the instrument is reduced, and the interference influence is accurately eliminated through amplitude and phase matching by a demodulation algorithm corresponding to a compensation light path; meanwhile, by dynamically observing and updating the return light intensity threshold, low-frequency disturbance is resisted, and accurate automatic focusing is achieved.

The invention discloses a cognitive function screening system and method based on an MMSE (Minimum Mean Square Error) prediction model, and relates to the technical field of data analysis, the method comprises the following steps: collecting physical examination index data, removing missing records, adopting a multiple interpolation method for interpolation, and obtaining multiple sets of complete data sets; a continuous prediction model is constructed, MMSE continuous prediction values are obtained, and a sensitivity analysis report is generated; constructing a first-stage classification model, adaptively dividing an optimal threshold combination, and dividing a sample into a high-confidence region, a to-be-discriminated region and a low-confidence region; if the sample size of the to-be-discriminated region is higher than a preset training threshold value, constructing an enhanced feature set, and constructing a second-stage classification model; when the prediction probability reaches the optimal re-discrimination threshold value, the classification result in the first stage is corrected, and otherwise, the classification result is maintained; if not, maintaining the classification result; and integrating the classification results to obtain a final classification result of all the samples.

The invention discloses a channel estimation method of a time-varying channel in a time delay-Doppler domain pilot mode, which comprises the following steps of: superimposing a hybrid superimposed pilot and a data symbol in a time delay-Doppler domain, the pilot comprising a high-power center pilot and a low-power edge pilot; the signal is converted to a time domain through inverse symplectic Fourier transform and Hisenberg transform; a receiving end obtains a receiving signal through Wigner transform and Sextile Fourier transform; estimating integer time delay and Doppler taps by using a center pilot frequency, and constructing a sparse channel matrix; estimating fractional Doppler and channel gain through a sparse Bayesian learning algorithm; and detecting a data symbol based on a minimum root-mean-square error algorithm, and realizing accurate estimation of channel parameters through iterative interference elimination. According to the method, the peak-to-average power ratio and the algorithm complexity can be effectively reduced, and non-correlation channel components and cross interference are inhibited.

The application relates to a kind of OFDM-based broadband millimeter wave relay system hybrid beamforming design method, comprising: calculating the receiving signal of target node under the condition that each node is all digital processor;The receiving signal is processed using minimum mean square error criterion in target node, and MMSE matrix is calculated;Using the equivalence between maximizing sum rate and minimum weighted mean square error algorithm, the maximum sum rate problem is converted into minimum weighted mean square error problem according to MMSE matrix;Deep unfolding neural network is used to solve the minimum weighted mean square error problem, and all digital processor of each node is obtained;Each node's all digital processor is decomposed based on least square decomposition algorithm, and hybrid beamforming matrix of each node is calculated, the complexity of the algorithm is greatly reduced, and the running time of the system can be effectively improved.

The invention provides a high resource efficiency allocation method in an intelligent reflecting surface assisted cellular-free large-scale MIMO (Multiple Input Multiple Output) system. The method comprises the following steps: establishing an intelligent reflecting surface assisted cellular-free large-scale MIMO system model under a Rician fading channel; based on the system model, performing channel estimation by using a linear minimum mean square error method; based on the system model, constructing a resource efficiency closed expression when the zero-forcing receiving scheme is used; according to the expression, constructing a non-convex optimization problem by taking maximization of system resource efficiency as a target, and decomposing the non-convex optimization problem into a power control sub-problem and a phase optimization sub-problem; and designing an alternative optimization algorithm according to the optimized sub-problems, and solving the power control sub-problem and the phase optimization sub-problem to obtain a power control coefficient and intelligent reflector shift. When a ZF receiving scheme is used, the resource efficiency optimization algorithm has excellent signal processing capacity, the system resource efficiency is remarkably improved, operation steps are convenient to implement, and the dual requirements of a future wireless communication system for high data rate and low energy consumption are met.

The application belongs to the technical field of unmanned aerial vehicles, and discloses an unmanned aerial vehicle target searching method and system based on an electromagnetic map. A wireless signal receiving element carried by the unmanned aerial vehicle receives radio frequency signals from a target. Terrain information, scene parameters and the radio frequency signal strength received in the first step are used to construct an electromagnetic map through electromagnetic wave propagation theory. The accurate target position coordinates are estimated through the least mean square error estimation method according to the electromagnetic map obtained in the second step. The unmanned aerial vehicle is controlled to fly to the specified position coordinates. The above steps are repeatedly performed until the search is successful or fails. The application fully utilizes the prior rich real terrain information through the low-cost and low-energy hardware requirement of the unmanned aerial vehicle end signal strength receiving, realizes the accurate positioning and searching of the radio frequency target, and is significantly superior to the algorithm without using the electromagnetic map in terms of accuracy and time efficiency.

The invention provides an uplink MIMO-NOMA (Multiple Input Multiple Output-Non-Orthogonal Multiple Access) system optimization method with a maximized sum rate, which comprises the following steps: firstly, in order to suppress interference between a transmission cluster and a reflection cluster, providing an inter-cluster SIC method: clustering users according to transmission characteristics, adopting space division multiple access in each cluster, and performing inter-cluster SIC of NOMA transmission so as to reduce the interference between the clusters; secondly, a non-convex optimization problem aiming at maximizing the total rate of the system is formulated and solved by using an alternating optimization framework, in the framework, a receiving equalizer is optimized according to a minimum mean square error standard, and transmitting power control of a user is processed through successive convex approximation, so that sub-problems are easy to process; and finally, the beam forming of the active STAR-RIS adopts a sequential rotation design. According to the invention, the dual-fading effect is effectively overcome by adjusting the phase shift and amplitude of electromagnetic waves, an alternating optimization framework is also provided to solve the described non-convex problem, user power is controlled through continuous convex approximation, and active STAR-RIS beam forming is realized through sequential rotation.

The application relates to a weak underwater target azimuth detection pre-tracking method based on belief propagation, which comprises the following steps: converting a weak target tracking problem into solving a joint posterior probability density function (pdf) based on a Bayesian rule; factorizing the joint posterior pdf, constructing a corresponding factor graph through a graph model; solving the transmitted information in the factor graph by using a belief propagation (BP) algorithm, and converting multiple integrals into ordinary integrals by using a Goodman variable substitution principle; constructing a likelihood function by using a complex Wishart distribution to describe the relationship between original sonar data and target states, and simplifying the remaining pdf by using a Gaussian distribution to obtain a confidence approximation of a target state edge posterior pdf; and calculating the number of weak targets and corresponding states by using a minimum mean square error (MMSE) estimator. The application can simultaneously track multiple weak targets without a complex clustering algorithm, has fewer preset parameters, and can accurately and efficiently track target state information including an azimuth, an azimuth angular velocity and target intensity.

The application discloses a dynamic human body reconstruction method based on a neural radiation field, and comprises the following steps: S1, establishing a dynamic human body reconstruction network based on a neural radiation field, wherein the dynamic human body reconstruction network comprises an action branch for acquiring an action field and a reconstruction branch for acquiring a neural radiation field; S2, initializing the action branch and the reconstruction branch in a specified resting posture by using a human body parameterized model; S3, using real images in a given posture and given camera internal and external parameters as a supervision signal, and simultaneously training the action branch and the reconstruction branch by taking the minimum mean square error between the real images and synthetic images as a loss function; and S4, inputting a new human body posture and a camera pose to the trained dynamic human body reconstruction network, and rendering a human body image in any view point in the new posture.

The invention is suitable for the technical field of geographic element data analysis, and provides a geographic spatiotemporal weighted vector autoregression-based multi-element collaborative change modeling method, which comprises the following steps of: constructing a GTWR-VAR model, and combining a multivariable feedback mechanism of vector autoregression with locality of geographic spatiotemporal weighted regression to obtain a GTWR-VAR model; the method comprises the following steps of: quantifying spatial-temporal heterogeneity of mutual influence among geographic elements, introducing a Bayesian optimization mechanism, adaptively determining an optimal lag order, a spatial bandwidth and a time bandwidth by taking verification set mean square error minimization as a target, and finally adopting Monte Carlo block permutation test to determine the optimal lag order, the spatial bandwidth and the time bandwidth on the premise of retaining inherent time autocorrelation of data. And evaluating and eliminating non-significant items in the local coefficient to ensure the statistical effectiveness of the result. According to the method, the continuous change rule of the influence mechanism between the geographic elements in time and space is disclosed, and a more accurate and reliable basis is provided for regional response research under fine management, prediction and climate change.

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 invention relates to the technical field of wireless communication, and discloses an RIS-assisted cellular-removal large-scale MIMO energy efficiency improvement method and system, and the method comprises the steps: building an RIS-assisted cellular-removal large-scale MIMO system under a Rician fading channel condition; based on the constructed MIMO system, channel estimation is carried out through a linear minimum mean square error method; based on the constructed MIMO system, deducing a closed expression of system energy efficiency based on a zero-forcing detector; constructing an energy efficiency optimization problem formula based on the closed expression; and according to the optimization problem formula, designing an alternate optimization algorithm to optimize the energy efficiency. The system corresponds to the method. By adopting the RIS-assisted honeycomb-removed large-scale MIMO energy efficiency improvement method and system provided by the invention, the energy efficiency performance of the system can be remarkably improved, and a foundation is laid for improving the performance of the MIMO system.

The application discloses a tracer identification positioning method, an electronic device, a storage medium and an apparatus. The method comprises the following steps: segmenting an intraoperative three-dimensional image by using different image segmentation thresholds, obtaining a suspected tracer ball meeting an identification condition each time, selecting suspected tracer balls with the same number as that of actual tracer balls to form a plurality of to-be-registered point sets, performing rigid registration on the actual tracer balls, and selecting a to-be-registered point set with the minimum mean square error as a candidate point set; selecting the candidate point set with the minimum mean square error as a final positioning point set; outputting coordinates of all points of the final positioning point set and a corresponding coordinate transformation matrix, and outputting that no tracer is identified if there is no candidate point set or the mean square error of the final positioning point set is greater than the radius of the actual tracer ball. The application automatically positions the tracer in the three-dimensional image in an iterative manner, can eliminate the influence of metal artifacts to the maximum extent, improves the positioning accuracy, and reduces the operation time.

The invention relates to the field of sound signal processing, and discloses a relay gateway echo cancellation method and device and a medium, and the method comprises the steps: obtaining a near-end voice instruction digital signal X (n) and a far-end reference signal Y (n) through a TDM bus interface, and n is a time domain sampling point sequence number; inputting the Y (n) into an adaptive filter bank, calculating a filter coefficient W (n) through a minimum mean square error criterion, and generating an analog echo signal; performing time domain subtraction operation on the X (n) to obtain a primary residual signal; performing non-linear distortion detection, and activating a secondary cancellation module when a non-linear component is detected; performing sub-band decomposition on the X (n) in the secondary elimination module, and generating a compensation signal C (n) by adopting a frequency domain weighting method; carrying out superposition processing on the residual signal and C (n), and outputting a final residual signal; the method has the beneficial effect that linear and nonlinear echoes are remarkably reduced.

The invention relates to the technical field of 5G communication channel estimation, and discloses a 5GMIMO channel estimation optimization method based on deep learning. According to the method, a deep learning model architecture is constructed, and model parameters are dynamically initialized according to channel coherence time so as to adapt to 5GMIMO channel multipath propagation characteristics. Received signal streams from a plurality of antenna elements containing different orthogonal frequency division multiplexing sub-carrier frequency sequences are processed, channel impulse response estimates are generated based on frequency domain correlation and input into a model for nonlinear transformation. And performing model parameter collaborative optimization, updating the network weight by calculating the gradient variation, constructing a target function according to channel delay extension and model depth association, and adjusting the estimation output towards the direction of minimizing the mean square error. And triggering model structure adaptation based on a norm of gradient variation, acquiring model copy parameters matched with the current channel state from an adjacent cell base station, normalizing the model copy parameters, and adjusting the number of attention heads or the number of residual blocks.

The invention discloses a message passing detection algorithm for a bidirectional transmission symbol probability of an orthogonal time frequency air conditioning signal, and provides a calculation formula of a bidirectional transmission probability message, a convergence judgment criterion of an iterative detection process and two methods for reducing calculation complexity. The error code performance of the detection algorithm is superior to that of a linear minimum mean square error detection algorithm and a traditional message passing detection algorithm, and the convergence speed is higher than that of the traditional message passing detection algorithm. After the two methods for reducing the calculation complexity are applied, the bit error rate performance is only slightly reduced, but the calculation complexity is obviously reduced.

The invention discloses an MIMO (Multiple Input Multiple Output) resource allocation method considering a channel estimation error and a related device, and the method comprises the steps: constructing a multi-cell MIMO system, and carrying out the estimation of a channel through employing an uplink orthogonal pilot frequency, and obtaining a least square and minimum mean square error estimation channel; estimating a channel according to the least square and the minimum mean square error, and determining an expected closed expression of a channel estimation error matrix; based on the channel hardening effect, with the average minimization of all users as the optimization target, a pilot frequency power distribution optimization problem is constructed, the pilot frequency power distribution optimization problem is solved, and the optimal pilot frequency power distribution scheme is obtained.By means of the method and the related device, pilot frequency pollution can be effectively relieved, the channel estimation precision is improved, and the channel estimation efficiency is improved. And meanwhile, balanced optimization of the overall performance of the system is realized.

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 invention provides a power distribution transmission method and device under an OCDM frequency selection channel, and the method comprises the steps: converting a time domain signal into a frequency domain through a discrete Fourier transform matrix at a transmitting end, generating a power distribution matrix through combining channel state information and adopting a water injection algorithm, and carrying out the dynamic power precoding of a frequency domain subcarrier; generating a time domain OCDM signal through an inverse discrete Fourier transform matrix and an inverse discrete Fresnel transform matrix, adding a cyclic prefix, and transmitting the time domain OCDM signal; after a receiving end is subjected to prefix removal, a discrete Fourier transform matrix is converted into a frequency domain, a frequency domain equalizer is designed on the basis of a minimum mean square error criterion by utilizing channel diagonalization characteristics, signals are equalized in combination with transmitting power information, and finally time domain information is recovered through an inverse discrete Fourier transform matrix; therefore, the problem of traditional power distribution failure caused by OCDM channel energy dispersion is solved, and through receiving and transmitting joint optimization, diversity gain is fully mined, frequency selective channel fading is adaptively matched, the anti-interference and anti-multipath capabilities of the system are improved, and the spectrum efficiency and the transmission performance are maximized.

The invention discloses a ship heave measurement research method based on minimum mean square error integrated navigation, belongs to the technical field of navigation, and aims at different sea condition environments, the method not only effectively inhibits noise frequency bands by using frequency domain point-by-point weighting, but also retains useful signals; efficient calculation is realized in combination with fast Fourier transform, and the method is suitable for real-time processing; and finally, a high-precision time domain heaving signal is obtained through inverse transformation, so that the output accuracy of the GNSS / INS integrated navigation system is remarkably improved, relatively high adaptability and reliability are achieved, and high-precision measurement of ship heaving motion is realized. The method comprises the following steps: constructing a frequency response function of a ship heave filter based on a minimum mean square error criterion; the method specifically comprises the following steps: carrying out difference on an elevation observation value obtained by a GNSS / INS integrated navigation system and heave true value data to obtain an elevation error sequence; then, power spectral density analysis is performed on the elevation error and the heave truth value signal to describe the energy distribution characteristics of the error and the target signal in the frequency domain so as to deduce the frequency response function of the filter. And after the construction is completed, multiplying the frequency response function by the frequency spectrum of the combined navigation elevation signal frequency point by frequency point to obtain a filtered frequency spectrum result. And finally, performing inverse Fourier transform on the frequency spectrum, and restoring the frequency spectrum to a time domain so as to obtain more accurate ship heaving motion information.

The application discloses a kind of distributed energy equipment-oriented license-free access method and related equipment, belong to wireless communication license-free random access technical field, central processing unit utilizes complex sequence convex optimization iteration decorrelation algorithm to optimize non-orthogonal structure pilot matrix, and the low coherence pilot obtained is distributed to equipment;Active equipment sends signal frame with pilot and data to wireless access point;Central processing unit estimates equipment active state using pilot in signal frame received by wireless access point, and on this basis, using linear minimum mean square error algorithm carries out channel estimation;Central processing unit uses data in signal frame received by wireless access point, and using successive interference cancellation technology decodes equipment data;Central processing unit adds combination filter in each iteration process of successive interference cancellation, compares signal-to-interference-and-noise ratio of each iteration process with threshold, and verifies whether decoding is successful.

The application provides a static positioning method and positioning device of a magnetic target, comprising: obtaining full tensor magnetic gradient data of a moving magnetic target at n measuring positions within a preset time period based on a static magnetic target positioning device; selecting one of the measuring positions as an initial position of the magnetic target, obtaining each measuring position of the magnetic target based on the initial position and full tensor invariant, and fitting according to the motion trajectory characteristics of the magnetic target to obtain a minimum mean square error after fitting; changing the initial position of the magnetic target and performing the above step cyclically; taking the initial position with the optimal minimum mean square error after fitting as a final solution, obtaining the position information of the magnetic target based on the full tensor invariant and the final solution of the initial position, and realizing the positioning of the magnetic target. The application realizes the positioning of the magnetic target based on the full tensor invariant and the motion trajectory constraint, can simply and quickly realize the positioning of the fixed magnetic moment magnetic source through a set of measuring processes and experimental data post-processing, and has high positioning precision and low cost.

This invention relates to a symbol detection method for an orthogonal time-frequency spatial modulation system combining LMMSE and MRC, belonging to the field of mobile communication. Based on the orthogonal time-frequency spatial OTFS modulation system, linear minimum mean square error (LMMSE) detection is first performed in blocks in the time domain. The detection results are then combined and converted to the time-delay-Doppler domain for orthogonal amplitude demodulation. The demodulated results are then converted to the time-delay-time domain and used as the initial values ​​for the maximum ratio combining (MRC) detection algorithm in the time-delay-time domain, thereby improving the bit error rate performance of the MRC detection method. Simulation experiments verify the effectiveness of this invention. Compared with other initialization detection methods, this method has a lower bit error rate at high communication rates and also exhibits superior performance in high-speed mobile scenarios.

The invention provides a channel estimation method for a minimum mean square error, which comprises the following steps of: performing Fourier transform on a received baseband signal to obtain OFDM (Orthogonal Frequency Division Multiplexing) frequency domain data, and obtaining frequency domain data of all symbols on a receiving side through solution resource mapping; the method comprises the following steps: processing by utilizing frequency domain data of a pilot symbol at a receiving side and a priori known pilot symbol sequence to obtain channel responses of SNR (Signal to Noise Ratio) estimation and LS (Least Square) channel estimation; processing according to the channel response of the LS channel estimation to obtain root-mean-square delay expansion; calculating a data-pilot frequency cross-correlation matrix and a pilot frequency self-correlation matrix according to root mean square time delay expansion, and calculating to obtain an MMSE filtering channel estimation coefficient according to the data-pilot frequency cross-correlation matrix and the pilot frequency self-correlation matrix; mMSE filtering is carried out according to the MMSE filtering channel estimation coefficient, and finally a final channel estimation value is obtained. According to the method, channel response is accurately estimated while operation is simplified, so that reliable communication and low operation delay are ensured.

This invention discloses a group-connected BD-RIS-assisted uplink communication system and a method for maximizing transmission rate, relating to the field of wireless communication technology. The method first establishes a channel model between the user, base station, and BD-RIS, derives the decoded signal expression for the user at the base station, and calculates the user's signal-to-interference-plus-noise ratio (SNR) and achievable rate. Then, it constructs an optimization problem with the goal of maximizing the system's sum and rate, with the optimization variables being the equalizer, user transmit power, and BD-RIS phase shift matrix. Finally, it employs an alternating optimization strategy, sequentially optimizing the equalizer based on the minimum mean square error criterion, transforming the non-convex problem into a convex problem to solve for the transmit power, and optimizing the phase shift matrix using the BFGS quasi-Newton method, iterating until the system performance converges. This invention overcomes the design limitations of traditional reconfigurable smart reflectors, fully leverages the control advantages of BD-RIS, effectively improves the sum and rate of the uplink communication system, and provides a new solution for future wireless network performance optimization.