44 results about "Doppler spread" patented technology

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.

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.

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 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 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.

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 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.

A device, such as a UE and a transmit / receive point (TRP), for providing network-assisted frequency offset compensation in a high-speed train single-frequency network (HST-SFN) is disclosed. The device includes a receiver that receives a first reference signal and a second reference signal transmitted from a first TRP via a wireless network. The first reference signal corresponds to the QCL RS of the second reference signal. The device receiver determines delay spread and average delay information of the path between the first TRP and the device based on the first reference signal. The device receiver also receives a third reference signal from the second TRP, which includes Doppler frequency shift and Doppler spread information and corresponds to the QCL RS of a fourth reference signal transmitted from the second TRP, or corresponds to the second reference signal transmitted from the first TRP in an SFN manner.

A generative neural network-based underwater acoustic OTFS communication transmission system and method are disclosed, relating to underwater communication transmission. Addressing the fractional spread problem caused by long delay spread and Doppler spread in broadband underwater acoustic channels, the system includes sequentially cooperating transmitter, receiver, channel estimation, and channel equalization units. The transmitter performs OTFS modulation, carrier modulation, and transmission; the receiver performs signal reception, preprocessing, and OTFS demodulation; the channel estimation unit combines a fractional-order dictionary matrix with a generative neural network, constructing a delay-Doppler domain refined grid and designing an unsupervised training model with double KL divergence constraints; and the channel equalization unit performs equalization processing and signal recovery. The method includes OTFS modulation transmission at the transmitter, underwater acoustic channel transmission, signal processing and demodulation at the receiver, generative neural network channel estimation, and equalization decoding. It requires no large number of labeled samples, has low computational complexity, short running time, and improves the transmission accuracy of underwater acoustic channels.

A terminal according to one embodiment of the present disclosure can: receive configuration information related to a wakeup signal (WUS) by means of higher-layer signaling; detect the WUS on the basis of the configuration information; determine a quasi co-location (QCL) type related to at least one from among Doppler shift, Doppler spread, average delay, delay spread and spatial Rx parameter on the basis of the capability of the terminal with respect to detection of the WUS; and detect the WUS on the basis of the QCL type.

The invention provides a signal detection method, apparatus and device, and a storage medium, which can effectively avoid the problem of self-information interference without introducing iterative feedback and feeding back the estimation result of the symbol for self-correction by constructing a state based on an original received symbol and a known channel structure, and improve the detection efficiency of the signal. An interference structure with any complexity can be accurately described, high-precision symbol detection is realized, and the method is suitable for any time delay-Doppler extension scene. In the process of advancing from the state of one received symbol to the state of another received symbol, the differentiated undetermined sending symbols playing a key information updating role between adjacent states are concerned, all sending symbols do not need to be reprocessed, joint search for full combinations is avoided, and the transmission efficiency is improved. The calculation complexity is reduced from the index level to the polynomial level related to the difference scale between the states, and the processing capacity is improved on the premise that the detection performance is not reduced.

This disclosure provides systems, apparatus, devices, and methods, including computer programs encoded on a storage medium, for switching waveforms in wireless communications. The UE (102) receives (434) a resume control message from the network entity (104) using the default waveform, the resume control message indicating a resume reference signal configuration and RACH resources. The UE (102) sends (440) a first report message on the RACH resource to the network entity (104) using the default waveform, the first report message indicating a delay spread and a Doppler spread measured from the recovery reference signal. The UE (102) receives (444) a RACH response from the network entity (104) using the default waveform, the RACH response comprising an indication of a configuration of an updated waveform for at least one of an uplink signal or a downlink signal based on the first report message.

A method of transmitting a binary data sequence over an OTFS communication channel subject to Doppler-spread is provided. The method implements an optimisation of the power ratio of pilot signals using solely information readily available at the transmitter, foregoing the need to perform end-to-end simulations or trials. A corresponding receiver performs a two-staged iterative channel estimation, signal detection, de-mapping and data-decoding, with information obtained from the decoded data being iteratively fed back to the channel estimation, signal detection, de-mapping and data decoding.

The received signal is sampled at the LiDAR system and converted to the frequency domain, wherein the received signal includes a first frequency waveform. A matched filter is selected, wherein the matched filter includes a second frequency waveform having a set of coefficients used to match the first frequency waveform. The set of coefficients is updated according to a set of metrics. The received signal is filtered by the matched filter to generate a filtered received signal. Range and velocity information are extracted from the filtered received signal.

The application belongs to the technical field of satellite communication, and discloses a multi-satellite cooperation multi-beam joint processing method based on regional statistical channel information, which comprises the following steps: 1, analyzing the channel correlation between the center and the edge of a region and between different regions, and determining a regional division scheme based on the correlation; 2, establishing a cooperative satellite set construction module with the target of maximizing the average spatial orthogonality of a satellite set and minimizing the Doppler spread; and 3, constructing a distributed multi-satellite cooperation multi-beam joint processing optimization scheme with the target of maximizing the system sum rate. In the case of lacking terminal position information, existing phased array antenna errors and malicious interference, the application realizes the significant improvement of the capacity of the center region and the edge region based on the regional statistical channel information and the multi-satellite cooperation multi-beam joint processing.

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.

A method (400, 500) for an apparatus, such as a User Equipment, UE, (110) and a Network Entity, NE, (120), in a wireless network provides a mechanism for overhead reduction for uplink precoder indication when some of the groups of UE antenna ports have substantially the same channel properties. The channel properties may be one or more of quasi-co-location correlation properties, including delay spread, average delay, Doppler spread, Doppler shift, spatial transmission filter, or average gain. These mechanisms may be employed when the operability of one or more antenna ports changes.

The application relates to an anti-high-Doppler orthogonal frequency division Doppler multiplex waveform design method, which comprises the following steps: step 1, digital modulation and OFDDM modulation are performed on data bits to obtain a baseband time domain signal; step 2, the modulated signal reaches a receiver through a time-varying multipath channel, and a frequency-Doppler domain representation of the channel is used to establish a mathematical model between a received signal and a transmitted signal; step 3, OFDDM demodulation is performed on the received signal r(t) by the receiver to obtain a frequency-Doppler domain symbol; and step 4, a frequency-Doppler domain symbol obtained through demodulation is used to extract channel Doppler diversity by using a maximum ratio combining algorithm based on interference cancellation. The superior technical effect of the design method is that the existing OFDM framework can be well compatible, the Doppler extension of the channel can be converted into the degree of freedom of diversity while adapting to the prior art, and the bit error rate performance of OFDM in a high-mobility scene can be greatly improved.

The application relates to a Bi-LSTM-SA low-complexity OTFS channel estimation method and system based on a basis expansion model and belongs to the technical field of wireless communication and deep learning. In view of the problems of low channel estimation accuracy and high equalization complexity in a high-speed mobile scene, the application converts time-domain channel estimation into low-dimensional basis coefficient estimation through a basis expansion model, extracts basis coefficient time sequence features by using a self-attention enhanced bidirectional long short-term memory network, and realizes high-precision channel estimation. Meanwhile, a two-stage equalizer is adopted, single-tap equalization is carried out in a time-frequency domain, and residual interference is suppressed through iterative interference cancellation in a delay-Doppler domain. The application effectively balances estimation accuracy and calculation complexity, and improves the anti-Doppler spread capability and spectral utilization efficiency of a system.

A method of a LIDAR system to compensate for mirror Doppler spread includes transmitting an optical beam towards a target, receiving a return signal from the target, and generating an electrical signal comprising a set of frequencies in a first frequency spectrum. The method further includes determining a value for each of a set of scanning parameters associated with the target, determining a spread function for the frequency spectrum based on the values for each of the scanning parameters, and performing a correction of the frequency spectrum based on the spread function.

A method of a LIDAR system to compensate for mirror Doppler spread includes transmitting an optical beam towards a target, receiving a return signal from the target, and generating an electrical signal comprising a set of frequencies in a first frequency spectrum. The method further includes determining a value for each of a set of scanning parameters associated with the target, determining a spread function for the frequency spectrum based on the values for each of the scanning parameters, and performing a correction of the frequency spectrum based on the spread function.

The invention relates to a system (1) and method for adaptive transmission design tailored to dynamically transmit a frame that emulates the periodic time-varying patterns of the micro-Doppler spread in scenarios involving devices performing rotational motion such as rotors.