Recursive compressed sensing method and system applied to shortwave ofdm dual-selection skywave channel estimation

Abstract

The invention discloses a recursive compressed sensing method and system applied to short-wave OFDM dual-selection sky wave channel estimation. The method is to reconstruct the consecutively transmitted Ω OFDM symbols in turn, set ω∈{0,...,Ω‑1}, and the process of reconstructing the ωth OFDM symbol is: when ω=0 , use the compressive sensing reconstruction algorithm to obtain the reconstructed signal of the ωth OFDM symbol; when ω>0, use the recursive compressed sensing reconstruction algorithm to obtain the reconstructed signal of the ωth OFDM symbol, and the recursive compressed sensing reconstruction algorithm uses the The c1 elements with larger amplitude in the reconstructed signal of (ω-1) OFDM symbols constitute the prior support set of the ω-th OFDM symbol, and the prior support set is used to perform recursive iterative operations to obtain the ω-th OFDM symbol. Reconstructed signal, c1 is a positive integer. The correlation of the channel sparse structure in the time dimension is fully considered, and the pilot overhead is greatly reduced while ensuring the reconstruction accuracy.

Description

technical field [0001] The present invention relates to the field of short-wave wireless communication, in particular to a recursive compressed sensing method and system applied to short-wave OFDM dual-selection sky wave channel estimation. Background technique [0002] Applying Orthogonal Frequency Division Multiplexing (OFDM) to short-wave communication can significantly improve spectrum utilization, and at the same time can suppress the interference of sky-wave channel multipath delay spread on short-wave communication. Due to the above-mentioned natural technical advantages, short-wave OFDM has become an important realization technology for a new generation of broadband high-speed short-wave communications. [0003] In a shortwave OFDM system, accurate channel state information (Channel State Information, CSI) is required for both channel equalization and signal detection at the receiver. However, the non-steady nature of the ionosphere makes the sky-wave channel experi...

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Problems solved by technology

At present, the research on shortwave channel estimation mainly focuses on the non-blind estimation method using the training sequence, such as the reconstruction algorithm of the shortwave channel using the orthogonal matching pursuit algorithm, which considers a single OFDM symbol for the research on dual-selective sky-wave channel estimation The sparsity of the channel coefficients in the period can be used to reduce the pilot overhead of the communication system and the complexity of the estimation algorithm. However, existing studies have shown that the change of the multipath delay of the wireless channel is usually slower than the change of the path gain, that is, the actual wireless channel is still Shows the correlation of the time dimension, the algorithm does not consider the influence of the correlation of the time dimension of the wireless channel in the reconstruction, resulting in low reconstruction accuracy

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