3 results about "Multipath channels" patented technology

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.

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.