Recursive compressed sensing method and system applied to short-wave OFDM double-selection sky wave channel estimation

Abstract

The invention discloses a recursive compressed sensing method and system applied to short-wave OFDM double-selection sky wave channel estimation. The method comprises the steps that omega OFDM symbolswhich are continuously transmitted are reconstructed in sequence, lower-case omega is set to belong to {0,..., omega-1}, and the reconstruction process of the lower-case omegath OFDM symbol is as follows: when lower-case omega is equal to 0, a compressed sensing reconstruction algorithm is utilized to obtain a reconstruction signal of the lower-case omegath OFDM symbol; when lower-case omega is larger than 0, a recursive compressed sensing reconstruction algorithm is used for obtaining a reconstruction signal of the lower-case omegath OFDM symbol, and the recursive compressed sensing reconstruction algorithm uses c elements with large amplitudes in the reconstruction signal of the (lower-case omega-1)th OFDM symbol to form a prior support set of the lower-case omegath OFDM symbol; and recursive iterative operation is performed by using the prior support set to obtain a reconstructed signal of the omega-th OFDM symbol, wherein c is a positive integer. The correlation of the channel sparse structure in the time dimension is fully considered, and the pilot frequency overhead is greatly reduced while the reconstruction accuracy is ensured.

Description

technical field [0001] The 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, it can suppress the interference caused by multi-path delay extension of sky-wave channel to short-wave communication. Due to the above-mentioned natural technical advantages, short-wave OFDM has become an important realization technology of a new generation of broadband high-speed short-wave communication. [0003] In a short-wave OFDM system, both channel equalization and signal detection at the receiving end require accurate channel state information (Channel State Information, CSI). However, the non-stationary characteristics of the ionosphere make the sky-w...

AI Technical Summary

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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