8 results about "Multipath channels" patented technology

This invention provides an adaptive method and system for fast spatial spectrum estimation of multipath channels. The method includes: S1, using a linear uniform array as the receiving array, with the first element in the array as the reference element, deriving the broadband signal model and steering vector matrix received by the array; S2, constructing a fitness function, and using the dung beetle algorithm to search for the optimal fractional Fourier transform order of the received signal from the reference element; S3, performing the optimal fractional Fourier transform on the received signal of the array; S4, finding the coordinates (u) corresponding to the maximum value. p ,v p S5. Energy detection: Set a threshold for comparison. If the threshold is met, it indicates that the location of this point is a component of the multipath; otherwise, the algorithm ends. S6. Use the CLEAN algorithm to separate the multipath components. The center frequency of its narrowband filter is u. p S7. Use the MUSIC algorithm to estimate the incident angle of the multipath components; S8. Mask the strongest component among the current multipath components and return to repeat steps S4 to S7 until all components are estimated.

A beamforming design method for intelligent metasurface arrays based on orthogonal time-frequency-space technology includes: aggregating multipath channels under direct illumination into cascaded channels with near-field direction vectors; randomly initializing the phase shift of intelligent metasurface units; establishing an effective channel matrix based on the cascaded channels; then establishing a multi-user and rate objective function; maximizing the objective function through phase shift optimization using a hierarchical search strategy; repeatedly executing the hierarchical search strategy to search and optimize subsequent blocks until the number of intelligent metasurface units in each block reaches a preset value; then performing an exhaustive search in the final block, thus completing one iteration; repeating the iteration until the maximum number of iterations is reached; outputting the final optimal phase shift; and implementing beamforming design based on the final optimal phase shift. This invention can reduce the complexity of beamforming design and ensure reliable transmission of high capacity during high-speed movement.

A priority-based centralized multi-AGV multi-path lane change decision planning method, comprising the following steps: S100: according to the pre-established multi-path lane passing rule, reasonably allocate path resources, and confirm the lane change decision result of whether the AGV under the multi-path lane needs to change lane; S200: according to the priority order of each AGV, receive the lane change decision result, plan the behavior level of the current AGV, plan the specific semantic action of lane change, and generate a time-space channel in the cloud for a single AGV. The method can make the multi-AGV system have stronger adaptability and higher efficiency on wide paths, and can reduce congestion and solve sudden situations on wide paths of the multi-AGV system.

The invention belongs to the technical field of radar radiation source signal intra-pulse analysis, and particularly relates to an intra-pulse modulation recognition method based on a time-frequency fusion graph and a radar graph convolutional network, and the method comprises the steps: constructing a new physically interpretable graph structured representation mode of a radar signal, and comprehensively utilizing the time-frequency information of the signal to form a time-frequency fusion graph; according to the method, the deep learning-based IPMR algorithm is adopted, and a special hierarchical residual image convolution network-radar map convolution network is specifically designed, so that the method can be directly generalized to a complex multi-path time-varying channel scene, and additional retraining is not needed, and therefore, a fundamental limitation of many existing deep learning-based IPMR methods can be broken through; according to the method, training can be carried out only under the additive white Gaussian noise channel, then time-varying multipath channels with different characteristics are directly adapted, priori knowledge of the channel and retraining on target domain data are not needed, and the method has the outstanding generalization advantage.

The application discloses a target detection method based on multi-path component reconstruction residual error, comprising the following steps: step 1: based on the double auto-encoder training algorithm of environmental clutter, learning the clutter structure features in the multi-path channel and reconstructing the multi-path echo; step 2: synthesizing the reconstructed multi-path echo obtained in step 1 into a reconstructed image, based on the target pre-detection algorithm of the reconstruction residual error, comparing the difference between the original image and the reconstructed image, and used for distinguishing whether the to-be-detected region contains target echo. The application fully explores the multi-path characteristics of the clutter, and realizes the weak and small target detection under the condition of no target sample through the multi-path echo reconstruction residual error.

This invention discloses a robust method and related equipment for extracting human vital signs information. The method includes: acquiring raw radio frequency data collected by radar; preprocessing the raw radio frequency data to obtain a target data matrix; identifying multipath channels based on the target data matrix; performing parallel phase demodulation on each identified multipath channel to obtain a phase sequence for each multipath channel; performing coherence analysis on the signal components of all phase sequences; adaptively weighting and fusing the phase sequences based on the results of the coherence analysis to obtain a fused vital sign signal; and performing vital sign analysis based on the fused vital sign signal to obtain the target vital sign information. This invention effectively solves the key technical problem of weak vital sign signals being submerged in complex environments through the collaborative processing of multipath signals, enabling high-precision and highly robust non-contact vital sign monitoring, and can be widely applied in the field of radar vital sign monitoring technology.

This invention discloses a wireless multiplexing random access method based on ZC sequences. It employs a waveform design based on ZC sequences and uses cyclic shift index modulation in the time domain to transmit multiple information bits per unit bandwidth. For multi-user access, it allows users to randomly select root sequences for uncoordinated random concurrent access and converts inter-user interference into additive white noise. Addressing the common "root collision" problem in concurrent scenarios, a constellation set matching-based decoding technique is proposed. This technique extracts spectral structure features from multipath channels to construct a reference constellation vector, achieving multi-user signal separation in severe collision and low signal-to-noise ratio environments. To address the sensitivity of ZC sequences to frequency offset, a composite preamble structure is designed. This not only achieves precise decoupling of carrier frequency offset and sampling time offset but also completes coarse- and fine-grained two-level joint estimation and compensation of frequency offset, further ensuring demodulation reliability and concurrent throughput in complex channels.

A method and apparatus are provided for directional communication systems in tactical environments, utilizing frequency-hopping signals to enhance low-probability-of-intercept, -detection, and -geolocation (LPI / LPD / LPG) performance; along with anti-jamming (AJ) performance, multiple access, and performance in multipath channels. Because frequency-hopping signals vary their radio frequency from dwell-to-dwell, this prevents conventional angle-of-arrival (AOA) estimation based on phase-differences. This disclosure presents a technique for AOA estimation for frequency-hopping signals with techniques for combining phase-difference measurements from multiple frequency-hopping dwells to achieve high-performance AOA estimation.