Signal detection method for underwater acoustic FBMC system

Abstract

The invention discloses a signal detection method for an underwater acoustic FBMC communication system. The method is a multi-carrier (FBMC) underwater acoustic communication technology based on a filter bank. The underwater acoustic FBMC communication signal detection method provided by the invention is a method for an underwater acoustic time delay-Doppler double extension channel model, and comprises the following steps of: realizing signal synchronization and Doppler estimation by using a group of positive and negative frequency modulation HFM signals; realizing carrier frequency offset (CFO) estimation by using a known pilot symbol; realizing channel estimation by using the pilot frequency symbol subjected to CFO compensation; constructing a joint transmission matrix according to the estimated channel; and segmenting the joint transmission matrix into a plurality of sub-matrixes, and sequentially carrying out channel equalization on each sub-matrix to obtain a symbol to be detected. The method has the advantages that the system overhead is reduced by multiplexing the HFM and the preamble; the constructed joint transmission matrix comprises all non-additive interference suffered by each receiving symbol, so that the equalization performance is improved; a balancing method of a sliding window effectively reduces the calculation complexity of the system.

Description

technical field [0001] The invention belongs to the field of multi-carrier communication, relates to an underwater acoustic multi-carrier signal detection method, in particular to a signal detection method for an underwater acoustic FBMC system. Background technique [0002] In the existing multi-carrier underwater acoustic communication technology, Orthogonal Frequency Division Multiplexing (OFDM) technology is mostly used. Compared with single-carrier underwater acoustic communication technology, OFDM can deal with multiple Channel conditions. However, in the OFDM system, since each sub-carrier needs to be orthogonal, it is very sensitive to inter-carrier interference. Intercarrier interference usually comes from Doppler shift and carrier frequency offset (CFO). The Doppler frequency shift is caused by the relative movement between the transceivers, and the CFO is mainly caused by the inconsistency of the crystal oscillator frequencies at the transceivers. Therefore, si...

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Problems solved by technology

In a radio communication system, since the relative speed of the transceiver is much lower than the propagation speed of electromagnetic waves, the Doppler factor is usually -6 , almost negligible, but in water, the speed of sound is slow (about 1400-1600 m / s), which results in the Doppler factor usually being 10 -3 level, not to be ignored

Although the existing technology focuses on solving the problem of inter-carrier interference in OFDM, it is still difficult to achieve better performance of Doppler compensation in the complex and changeable underwater acoustic channel environment.

In addition, a cyclic prefix or guard interval is required before each OFDM symbol to avoid inter-symbol interference and reduce spectral efficiency

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