91 results about "Doppler spread" patented technology

A communication device receives, from another communication device, a set of transmissions over a sidelink shared channel, or over a downlink shared channel (1005). The communication device estimates a Doppler spread or a delay spread based on the received set of transmissions over the shared channel (1010). The communication device selects a reference signal configuration, from multiple reference signal configurations, based on the estimated Doppler spread or the estimated delay spread (1015). The reference signal is a DMRS, a PTRS and / or a TRS. Finally, the communication device transmits feedback indicating the selected reference signal configuration for a subsequent set of transmissions over the shared channel (1020).

The invention provides a method for transmitting a binary data sequence on an OTFS communication channel influenced by Doppler spread. According to the method, the optimization of the pilot signal power ratio can be realized only by using the existing information of the transmitter end, and end-to-end simulation or test is not needed. A corresponding receiver executes two-stage iterative channel estimation, signal detection, demapping and data decoding, and iteratively feeds back information obtained from decoded data to channel estimation, signal detection, demapping and data decoding.

A communication frame for an OTFS transmission system includes first-type and second-type blocks. The first-type block includes pilot signals, guard signals, and data signals, the second-type block exclusively includes data signals. The pilot symbols, guard signals, and data symbols of the first-type block, and the data symbols of the second-type block, are arranged along the points of a grid in the delay-Doppler domain. In the communication frame, a first-type block is followed by a second-type block, and a second-type block is followed by a first-type block. In the first-type block at least one pilot symbol is surrounded on at least three sides by one or more guard symbols. Points of the grid of the first-type blocks in the delay-Doppler domain that are not occupied by pilot symbols or guard symbols are used for data symbols. The communication frame permits determining oscillator frequency offset and channel coefficients in a receiver.

A communication frame for an OTFS transmission system includes at least one first-type and at least one second-type block. At least the first-type block includes data signals two-dimensionally arranged along the delay domain and the Doppler domain of which at least one has a superimposed pilot signal. The second-type block includes data signals two-dimensionally arranged along the delay domain and the Doppler domain which may or may not have superimposed pilot signals. At least one second-type block is preceded and followed, in the delay-domain, by first-type blocks, the first-type blocks preceding and following a second-type block having at least one identical data symbol and associated superimposed identical pilot symbol at an identical location in the two-dimensional arrangement. An OTFS transmitter generates and transmits the communication frame, and a receiver uses its properties for compensating oscillator frequency offset and channel estimation.

The present invention discloses an improved broadband shortwave channel simulation calculation method based on ITS, comprising the following steps: step 1, random modulation function simulation: step 2, phase determination function simulation: step 3, improved delay power distribution function simulation: step 4, defining the time-varying pulse response as a function of time and delay variables. The method disclosed by the present invention improves the delay power distribution function in the ITS channel model, making its calculation process simpler, thereby realizing the simulation calculation of broadband shortwave channels more quickly and conveniently, and the obtained shortwave channel model takes into account the shortwave signal delay and Doppler expansion effect caused by the ionosphere, and can simulate and calculate the shortwave link channel in any region of the world.

A method and system are disclosed for optimizing downlink multi-user multiple-input multiple-output (MU-MIMO) transmission in time division duplex (TDD) wireless communication systems. Sounding reference signals (SRS) from user equipment (UEs) are processed using a machine-learned model to extract physical-layer channel characteristics, including Doppler spread, delay profile, and signal-to-noise ratio (SNR). Based on these features, a channel state information (CSI) acquisition operation is adaptively selected for each UE—either channel estimation (CE) alone or both CE and channel prediction (CP). When CP is used, prior channel estimates are analyzed to generate predicted CSI over a future interval. The obtained CSI is then used to configure MU-MIMO transmission parameters such as beamforming weights, modulation and coding schemes (MCS), and UE grouping. This adaptive framework improves performance in time-varying and high-mobility environments by ensuring timely and reliable CSI is used for downstream transmission decisions.

The invention discloses an underwater acoustic spread spectrum communication Doppler estimation algorithm based on matched filtering and a fuzzy function, and belongs to the technical field of underwater acoustic communication. The method specifically comprises the following steps of: 1, performing Doppler estimation on a signal based on matched filtering, and determining a rough frequency offset range to obtain a rough estimation Doppler factor; 2, Doppler estimation based on a fuzzy function is carried out on the signal, and a fine estimation Doppler factor is obtained; and step 3, carrying out residual Doppler differential demodulation to obtain a final estimated Doppler factor. According to the method, the defect that a large Doppler spreading factor generated during high-speed movement between underwater mobile nodes cannot be well estimated by a matched filtering-based estimation method can be overcome, and the defects that a fuzzy function estimation method with higher precision is long in consumed operation time and high in calculation complexity are overcome.

The present invention discloses a broadband shortwave channel simulation calculation method based on a ray tracing algorithm and an ITS model, comprising the following steps: step 1, setting the geographical longitude and latitude information of the transmitting point position and the receiving point position; step 2, using the ionosphere background model to calculate the ionosphere electron density and its gradient of change in all directions; step 3, using a three-dimensional ray tracing algorithm to calculate the propagation parameters of the shortwave signal propagating between the transmitting and receiving point positions, including the minimum delay, maximum delay, average delay and Doppler frequency shift; step 4, using the propagation parameters calculated by the three-dimensional ray tracing algorithm or the propagation parameters obtained by experimental data as input, and obtaining the impulse response function of the shortwave channel according to the ITS model. The method disclosed by the present invention realizes broadband shortwave channel simulation calculation, and the obtained shortwave channel model takes into account the shortwave signal delay and Doppler expansion effect caused by the ionosphere, and can simulate and calculate the shortwave link channel in any region of the world.

A system can utilize a first common physical uplink control channel (PUCCH) format 1 communication format for broadband cellular communications with user equipment via a channel. The system can estimate a first channel characteristic based on performing channel estimation on the channel over uplink signals, which comprises a Doppler spread. The system can estimate a second channel characteristic based on the performing of the channel estimation over uplink signals, which comprises a delay spread. The system can determine a number of symbols for a second common PUCCH format 1 communication format with the user equipment based on the first channel characteristic. The system can determine a group of initial cyclic shift indices for the second common PUCCH format 1 communication format with the user equipment based on the second channel characteristic. The system can communicate with the user equipment according to the second common PUCCH format 1 communication format.

A communication frame for an OTFS transmission system includes at least one first-type and at least one second-type block. At least the first-type block includes data signals two-dimensionally arranged along the delay domain and the Doppler domain of which at least one has a superimposed pilot signal. The second-type block includes data signals two-dimensionally arranged along the delay domain and the Doppler domain which may or may not have superimposed pilot signals. At least one second-type block is preceded and followed, in the delay-domain, by first-type blocks, the first-type blocks preceding and following a second-type block having at least one identical data symbol and associated superimposed identical pilot symbol at an identical location in the two-dimensional arrangement. An OTFS transmitter generates and transmits the communication frame, and a receiver uses its properties for compensating oscillator frequency offset and channel estimation.

The invention relates to the technical field of 5G communication security, and discloses a 5G short message encrypted transmission method, which comprises the following steps: acquiring time delay spread, angle spread and Doppler spread parameters of indoor multipath propagation, and generating a multi-dimensional channel characteristic matrix; acquiring a historical channel fingerprint database and a current channel feature matrix, and outputting a channel anomaly score; generating a three-dimensional decision space coordinate by using a threat-performance joint state space mapping algorithm; monitoring the real-time encryption queue length and the processing delay of each slice, calculating the actual SLA fulfillment rate and the security event interception rate, and generating a performance feedback vector; and inputting the performance feedback vector into a reward function calculation module of the reinforcement learning model, updating model parameters, and outputting an optimized decision strategy. According to the method, the interference of environmental noise on threat detection is avoided, the accuracy of pseudo base station attack identification is improved, and the problem of resource conflict arbitration in a multi-network slice scene is solved.

A communication frame for an Orthogonal Time-Frequency Space (OTFS) transmission system includes at least one first type block and at least one second type block. The first type block comprises data signals arranged in a two-dimensional pattern along the delay and Doppler domains, wherein at least one data signal has a superimposed pilot signal. The second type block comprises data signals arranged in a two-dimensional pattern along the delay and Doppler domains, which may or may not have a superimposed pilot signal. At least one second type block is surrounded by a first type block in the delay domain, and one or more first type blocks surrounding the second type block have at least one identical data symbol and an associated identical superimposed pilot symbol at the same position in the two-dimensional pattern. An OTFS transmitter generates and transmits the communication frame, and a receiver utilizes its characteristics for oscillator frequency offset compensation and channel estimation.

An apparatus and method to receive a time / frequency tracking signal in a wireless communication network such as a 5G New Radio (NR) network. A user equipment (UE) receives from a network node a refe

The application provides a kind of air-ground channel modeling method suitable for millimeter wave phased array, comprising: step 1, establishing the Two-Ray channel geometric model of direct path and multiple reflection paths;Step 2, according to the geometric model, calculate the Rician factor;Step 3, according to the geometric model, determine the time delay of the reflection path;Step 4, according to the carrier frequency and the speed of motion, determine the Doppler frequency offset of the direct path;Step 5, according to the geometric model and Jacks distribution, determine the Doppler power spectrum of the reflection path;Step 6, based on the generalized stationary uncorrelated scattering model, establish the channel model. Through the application, a high-accuracy phased array air-ground channel model can be established, by considering the departure angle of the phased array transmitting antenna and the arrival angle of the receiving antenna in the air-ground channel model, the accuracy of the Rician factor calculation and the accuracy of the Doppler spread power spectrum in the fading channel can be improved.

The application discloses a frame structure design method of an AFDM system based on adaptive asymmetric guard bands, solves the problem that the frame structure design of the AFDM system under a high dynamic channel is difficult to simultaneously consider the bit error rate of a receiving end and spectral efficiency, and belongs to the technical field of information and communication.The application comprises the following steps: performing frame-level reliability determination according to a demodulation result vector of a current frame, when a corresponding threshold is satisfied, the current frame accesses an adaptive updating process; on the current frame that accesses, candidate pairs of a time delay index and a Doppler index are obtained, an effective path set of the current frame is screened out, a maximum Doppler spread priori and a Doppler energy directionality priori are extracted from the effective path set, a total guard band width of a next frame and a smooth direction factor are determined, asymmetric distribution of the lengths of guard bands on the left and right sides of a pilot is carried out according to the total guard band width of the next frame, the guard bands are relatively widened on the side of a Doppler energy concentration and are relatively shortened on the side of energy sparseness, and a next frame adaptive asymmetric guard band and a data area layout are generated.

The present invention discloses a RIS phase shift optimization method and system in a V2V communication system, which relates to the field of communication technology. The method comprises: based on a first position, a second position and a third position, respectively determining an incident channel elevation angle, an incident channel azimuth angle, a reflected channel elevation angle and a reflected channel azimuth angle, as well as a vehicle-to-vehicle channel delay, a channel delay from a first vehicle to each component in a RIS element, and a channel delay from each component in a RIS element to a second vehicle, and then sequentially calculating the signal receiving power of the second vehicle and the maximum power RIS phase shift; further calculating the minimum Doppler spread RIS phase shift; and determining the optimal RIS phase shift in the V2V communication system based on the maximum power RIS phase shift and the minimum Doppler spread RIS phase shift. The present invention realizes the phase shift optimization of the RIS element in the V2V communication system, which helps to improve communication efficiency and stability.

In embodiments, an electronic device is provided. The electronic device may comprise: at least one processor; and a memory for storing instructions. The instructions, when executed by the at least one processor, may cause the electronic device to: acquire first uplink reference signals in a first symbol; acquire a first channel estimation result for the first symbol by using the first uplink reference signals; acquire second uplink reference signals in a second symbol after the first symbol; determine a first communication quality index using the first uplink reference signals, and the first channel estimation result for the first symbol; determine a second communication quality index using the second uplink reference signals, and the first channel estimation result for the first symbol; and determine Doppler spread information corresponding to the difference between the first communication quality index and the second communication quality index.

The application belongs to the technical field of radar signal processing, and specifically discloses a method for detecting airspeed targets based on long-time accumulation, which comprises the following steps: firstly, segmenting the echo signals after pulse compression according to the number of pulses, and compensating the distance migration and Doppler spread of the envelope of the echo signals in each segment; secondly, performing in-segment coherent accumulation on the compensated results in each segment; and finally, performing envelope migration and non-coherent accumulation between segments on all the echo signals, so that the energy of the echo signals can be effectively accumulated. The long-time accumulation method of time segmentation, in-segment coherent accumulation and inter-segment non-coherent accumulation can solve the problems of long-time coherent accumulation calculation and echo signal coherent deterioration, improve the detection performance, and is easy to implement in engineering.

The invention provides a resource allocation method and a related device. In the resource allocation method provided by the application, the network device indicates the Doppler spread and / or the time delay spread of each DMRS in the at least one DMRS to the terminal device through the first information, equivalently, the DD domain resource matching the Doppler spread demand and / or the time delay spread demand of each DMRS is allocated for each DMRS, thereby reducing the resource overhead of the DMRS and improving the resource utilization rate.

The invention discloses a distance Doppler two-dimensional plot condensation method based on annular traversal, and the method comprises the following steps: obtaining a binary matrix through constant false alarm detection based on an echo distance Doppler spectrum; obtaining an echo distance Doppler extension matrix and an extension binary matrix through Doppler dimension extension and distance dimension extension based on an echo distance Doppler spectrum and the binary matrix; based on the extended binary matrix, a target scattering point set is obtained through two-dimensional grid search from the distance dimension to the Doppler dimension, a target matrix is obtained based on the echo distance Doppler extended matrix and the target scattering point set, and the two-dimensional grid search from the distance dimension to the Doppler dimension is annular traversal strategy search; and obtaining target trace point information through target trace point condensation based on the target matrix.

The invention provides a spatial multi-target detection network layout optimization method based on GNSS-R. According to the method, projects such as coverage rate, direct / reflected signal intensity, GDOP, time delay / Doppler broadening and the like are quantified into multi-target vectors based on physically-driven pseudo target point cloud and link simulation, and spatial multi-target positioning and speed measurement precision is improved through a multi-target joint optimization method. According to the method, in order to solve the convergence and uniformity problems of high-dimensional multi-objective optimization, a hybrid association criterion is put forward on an NSGA-III framework; and adaptability improvement is carried out on the density sensing micro population, the scale of reference points is reduced, and the local search capability is enhanced while a boundary extreme solution is reserved. Simulation experiments show that the average positioning error is 9.91 m and the speed measurement error is 0.4385 m / s under the condition that the number of the receiving units is obviously reduced, the requirement of space target detection is met, and a new way is provided for off-line planning and near-real-time deployment of a space multi-target detection network.

A communication method and apparatus are used for improving communication performance. The method may include determining a first signal and transmitting the first signal. Wherein the first signal is determined based on a first sequence, and the first sequence is determined based on a base sequence and an extended sequence; the base sequence is a ZC periodic continuation sequence; the expansion sequence is a cyclic shift sequence, and the fuzzy function of the first sequence is equal to zero in the maximum delay spread and maximum Doppler spread range, or the expansion sequence is a cubic polynomial index sequence, and the fuzzy function of the second sequence is equal to zero in the maximum delay spread and maximum Doppler spread range. The fuzzy function of the first sequence is smaller than or equal to a fuzzy function threshold value within the maximum delay spread and the maximum Doppler spread range. The first sequence is constructed through the base sequence and the extended sequence, so that the first sequence can be used for various physical channels and physical signals, the first signal is transmitted based on the first sequence, and the communication performance can be improved.

A communication method and apparatus are used for improving communication performance. The method comprises the following steps: a first communication device determines a first signal and sends the first signal; wherein the first signal is determined based on a first sequence, and the first sequence is determined based on a base sequence and an auxiliary sequence; wherein the base sequence is an ideal autocorrelation function sequence, the auxiliary sequence is a cyclic shift sequence, and the fuzzy function of the first sequence is equal to zero in the maximum delay spread and maximum Doppler spread range; or, the base sequence is an optimal self-ambiguity function sequence, the auxiliary sequence is a quadratic polynomial exponential sequence, and the ambiguity function of the first sequence is smaller than or equal to an ambiguity function threshold within the maximum delay spread and maximum Doppler spread range. The first sequence is constructed through the base sequence and the auxiliary sequence, so that the first sequence can be used for various physical channels and physical signals, the first signal is transmitted based on the first sequence, and the communication performance can be improved.

A communication frame for an OTFS transmission system includes first-type and second-type blocks. The first-type block includes pilot signals, guard signals, and data signals, the second-type block exclusively includes data signals. The pilot symbols, guard signals, and data symbols of the first-type block, and the data symbols of the second-type block, are arranged along the points of a grid in the delay-Doppler domain. In the communication frame, a first-type block is followed by a second-type block, and a second-type block is followed by a first-type block. In the first-type block at least one pilot symbol is surrounded on at least three sides by one or more guard symbols. Points of the grid of the first-type blocks in the delay-Doppler domain that are not occupied by pilot symbols or guard symbols are used for data symbols. The communication frame permits determining oscillator frequency offset and channel coefficients in a receiver.

The invention belongs to the technical field of wireless communication, and particularly relates to a fractional order adaptive optimization short wave channel parameter estimation method. Aiming at the time-frequency double-color dispersion characteristic caused by short-wave channel multipath and Doppler spread, firstly, the fractional order Fourier transform energy focusing degree is constructed as a self-adaption degree function, and the fractional order is mapped into the individual position of a sparrow; then, a sparrow search algorithm is utilized to adaptively search a global optimal fractional order in a given order interval, so that high calculation overhead of traditional traversal search is avoided, and meanwhile, the problem that single-peak search is easy to fall into local optimum due to low signal-to-noise ratio and multipath superposition is solved; and finally, peak information is extracted under the optimal fractional order, and joint estimation of multipath time delay, Doppler frequency shift and signal-to-noise ratio is completed. According to the method, the calculation complexity of order search is remarkably reduced while the parameter estimation precision is ensured, the estimation robustness in a low signal-to-noise ratio environment is improved, and good engineering realizability is achieved.

The invention belongs to the technical field of radar target simulation, and relates to a high-resolution close-range radar target simulation method and system based on DRFM. Target modeling is completed through a dynamic filter network, and a target feature sequence dynamically changing along with a radar view field is generated; inherent time delay calibration and cross-period compensation parameter calculation of the system are completed through measurement; after a radar transmitting signal is received, a zero-intermediate-frequency IQ signal is obtained through frequency conversion, sampling and frequency mixing; convolution modulation of the IQ signal and the target feature sequence is completed through an adaptive segmentation convolution algorithm, and a high-resolution target echo signal is generated; doppler frequency shift and distance shift are superposed, digital-to-analog conversion and radio frequency up-conversion are completed after cross-period compensation, and a target echo radio frequency signal is output. According to the method, the calculation complexity and the hardware cost of high-resolution target simulation are greatly reduced, ultra-short-distance simulation adaptive to a multi-signal system is realized, Doppler broadening distortion in a large-bandwidth scene is effectively inhibited, and the applicability is wide.

The present invention discloses a candidate position determination method, apparatus, device and product for target positioning, comprising: determining the time delay spread width and the Doppler spread width according to the type of positioning signal sent by a known target; determining the first step length according to the time delay spread width, and determining the second step length according to the Doppler spread width; determining the equal time delay difference direction angle; taking the first candidate position as the starting point, determining the second candidate position according to the equal time delay difference direction angle, the first step length and the second step length. The present invention can determine the spread characteristics of the positioning signal according to the type of positioning signal sent by a known target, further obtain the sampling direction and search step length of the candidate position, and determine a new candidate position. This method can effectively reduce the number of candidate positions while ensuring the accuracy of target positioning, significantly reduce the amount of calculation for later target positioning, improve the positioning speed of the target, and reduce the computing performance requirements for the target positioning device.

The invention discloses an AFDM system frame structure design method based on a self-adaptive asymmetric guard band, solves the problem that the frame structure design of the AFDM system under a high dynamic channel is difficult to consider the bit error rate and the spectrum efficiency of a receiving end at the same time, and belongs to the technical field of information and communication. The method comprises the following steps: carrying out frame-level reliability judgment according to a demodulation result vector of a current frame, and when a corresponding threshold is met, allowing the current frame to enter a self-adaptive updating process; on an admitted current frame, obtaining candidate pairs of a time delay index and a Doppler index, screening out an effective path set of the current frame, extracting maximum Doppler extension priori and Doppler energy directivity priori from the effective path set, and determining the total protection width and a smooth direction factor of a next frame; and asymmetrically distributing the lengths of the guard bands at the left and right sides of the pilot frequency according to the total protection width of the next frame, so that the guard bands are relatively widened at the Doppler energy dense side and relatively shortened at the energy sparse side, and generating the self-adaptive asymmetric guard band and data area layout of the next frame.

The application discloses a channel state information (CSI) measurement method, a terminal and a network side device, and belongs to the technical field of communication. The CSI measurement method comprises the following steps: a network side device sends CSI measurement configuration information to a terminal, wherein the CSI measurement configuration information is used for configuring target CSI measurement resources associated with target CSI information; and the network side device receives the target CSI information from the terminal. The target CSI information comprises at least one of the following: a Doppler frequency offset, a Doppler spread, a Doppler spectrum, a time domain channel correlation matrix, a delay spread, an average delay, a delay spectrum and a frequency domain channel correlation matrix.

The present application belongs to the technical field of radar target simulation, and relates to a high-resolution near-range radar target simulation method and system based on a DRFM. The present application completes target modeling through a dynamic filter network, generates a target feature sequence that dynamically changes with a radar field of view; completes inherent delay calibration and cross-cycle compensation parameter calculation through measurement; after receiving a radar transmission signal, obtains a zero intermediate frequency IQ signal through frequency conversion, sampling and mixing; completes convolution modulation of the IQ signal and the target feature sequence through an adaptive segmented convolution algorithm, generates a high-resolution target echo signal; superimposes Doppler frequency shift and distance offset, completes digital-to-analog conversion and radio frequency up-conversion after cross-cycle compensation, and outputs a target echo radio frequency signal. The present application greatly reduces the calculation complexity and hardware cost of high-resolution target simulation, realizes multi-signal system adaptation for super-near-range simulation, effectively suppresses Doppler spread distortion in a large bandwidth scene, and has wide applicability.