A 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 filter bank based multi-carrier (FBMC) underwater acoustic communication technology. The underwater acoustic FBMC communication signal detection method proposed by the method is a method for the underwater acoustic time delay-Doppler double-spread channel model, and the steps include: using a set of positive and negative frequency modulation HFM signals to achieve signal synchronization and Doppler estimation; Use the known pilot symbols to estimate the carrier frequency offset (CFO); use the CFO-compensated pilot symbols to estimate the channel; construct a joint transmission matrix according to the estimated channel; divide the joint transmission matrix into multiple sub-matrices, and sequentially Perform channel equalization on each sub-matrix to obtain symbols to be detected. The advantages of the invention are: the multiplexing of the HFM and the preamble reduces the system overhead; the constructed joint transmission matrix includes all the non-additive interferences received by each received symbol, thereby improving the equalization performance; the equalization method of the sliding window effectively reduces the System computational complexity.

Description

technical field [0001] The invention belongs to the field of multi-carrier communication, and 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, the Orthogonal Frequency Division Multiplexing (OFDM) technology is mostly used. Compared with the single-carrier underwater acoustic communication technology, OFDM can deal with multiple path conditions. However, in the OFDM system, since each sub-carrier is required to be orthogonal, it is very sensitive to inter-carrier interference. Inter-carrier interference usually comes from Doppler shift and carrier frequency offset (CFO). The Doppler frequency shift is caused by the relative motion between the transceiver and the CFO, and the CFO is mainly caused by the inconsistency of the crystal frequencies of the transceiver. ...

AI Technical Summary

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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