Doppler extension estimation method of MIMO-OFDM underwater acoustic communication system

A MIMO-OFDM and Doppler extension technology, applied in the field of underwater acoustic communication, can solve the problem of low estimation accuracy

Inactive Publication Date: 2016-11-09
SOUTHEAST UNIV
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Problems solved by technology

[0006] Technical problem: In order to solve the problem of low estimation accuracy of the existing Doppler estimation scheme in the underwater acoustic communication system, the present invention provides a Doppler extension estimation method for the MIMO-OFDM mobile underwater acoustic communication system, which makes full use of the good training sequence The autocorrelation characteristics and the diversity gain brought by MIMO technology can obtain higher estimation accuracy of Doppler spread factor

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  • Doppler extension estimation method of MIMO-OFDM underwater acoustic communication system
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  • Doppler extension estimation method of MIMO-OFDM underwater acoustic communication system

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Embodiment Construction

[0036] The present invention will be further described below in conjunction with the accompanying drawings.

[0037] Let the number of transmitting antennas of the MIMO-OFDM system be N t , the number of receiving antennas is N r , the signal adopts OFDM modulation based on cyclic prefix (Cyclic Prefix, CP) to prevent intersymbol interference, let B be the channel bandwidth, K be the number of subcarriers, then the subcarrier spacing is Δf=B / K, one OFDM symbol The duration is T=1 / Δf=K / B, and the cyclic prefix time length of each OFDM symbol is T g .

[0038] Such as figure 1 , 2 As shown, the frequency domain structure of the training sequence used in the present invention is the HT-LTF part of the 40MHz mixed mode preamble in the IEEE802.11n protocol. The training sequence contains two identical OFDM symbols, let s=[s[0],s[1],…,s[K-1]] T Represents the frequency domain sequence of an OFDM symbol, then the baseband training sequence of the mth frame data can be written a...

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Abstract

The invention discloses a doppler extension estimation method of an MIMO-OFDM underwater acoustic communication system. Two repeated training sequences are sent at a transmitting terminal; and a receiving terminal employs a plurality of parallel correlators to carry out delay correlation operation on received signals. And according to a window length of a correlator of a maximum output result, doppler expansion extension factor estimation is carried out. On the basis of the provided training sequence structure suitable for the scheme, the diversity gain brought by an MIMO technology is utilized fully. Compared with the traditional method for doppler extension factor estimation based on a chirp signal, the provided method enables the doppler extension factor estimation precision to be improved obviously.

Description

technical field [0001] The invention relates to the field of underwater acoustic communication, in particular to a Doppler extension estimation method in a MIMO-OFDM mobile underwater acoustic communication system. Background technique [0002] Bandwidth and spectrum utilization are two key factors that affect the information transmission rate of a communication system. MIMO technology can significantly improve the spectrum utilization by transmitting and receiving signals through multiple antennas at the same time, so it has been obtained in the underwater acoustic communication system with limited bandwidth. Extensive attention and research have introduced MIMO technology in both single-carrier transmission and OFDM multi-carrier transmission. [0003] In digital communication, especially in the OFDM system, frequency synchronization at the receiving end is a key issue, and the accuracy of frequency offset estimation will affect the demodulation and decoding process of the...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/69H04B13/02
CPCH04B1/69H04B13/02
Inventor 李春国宋康张行曹冰昊杨绿溪
Owner SOUTHEAST UNIV
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