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Short wave OFDM (orthogonal frequency division multiplexing) channel estimating method in narrow band interference

A technology of channel estimation and narrowband interference, which is applied in the field of channel estimation of short-wave OFDM systems, and can solve problems such as channel narrowband interference

Active Publication Date: 2015-05-13
CHONGQING UNIV OF POSTS & TELECOMM
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Problems solved by technology

Considering that the short-wave OFDM system is subject to the narrow-band interference problem caused by the traditional narrow-band short-wave signal not exceeding 3kHz

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  • Short wave OFDM (orthogonal frequency division multiplexing) channel estimating method in narrow band interference
  • Short wave OFDM (orthogonal frequency division multiplexing) channel estimating method in narrow band interference
  • Short wave OFDM (orthogonal frequency division multiplexing) channel estimating method in narrow band interference

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Embodiment Construction

[0055] A non-limiting embodiment is given below in conjunction with the accompanying drawings to further illustrate the present invention. It should be understood, however, that these descriptions are exemplary only, and are not intended to limit the scope of the invention. Also, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concept of the present invention.

[0056] The method designed in the present invention is applied to the short-wave OFDM system. A classic shortwave channel transmission model—ITS model proposed by scientists such as Vogler and Hoffmeyer of the ITS organization in the United States, in which the number of subcarriers is N and the number of pilot carriers is N p , the length of the cyclic prefix code is N g , the bandwidth is 3kHz, and the signal modulation method is 8PSK. In order to suppress the fast fading pilot caused by multipath interference, the comb pilot is se...

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Abstract

The invention discloses a short wave OFDM (orthogonal frequency division multiplexing) channel estimating method in narrow band interference. The method includes the steps: firstly, estimating an initial estimation value of a pilot frequency in a channel by the aid of an LS (list scheduling) algorithm, then performing a primary noise filtration for the initial estimation value by the aid of DFT (discrete Fourier transformation) channel estimation algorithm principle, namely, the length of a circulation prefix code is larger than channel impact response, filtering noise except a circulation prefix by the aid of a method that an estimation value larger than the length of the circulation prefix code is reset zero, finally, performing a secondary noise filtration for the initial estimation value by leading in a threshold value, acquiring a final estimation value at the pilot frequency by performing zero setting for signals smaller than the threshold value and keeping invariable for the portions larger than the threshold value, then performing interpolation for pilot frequency estimation according to interpolation modes to obtain estimation of the whole channel, and performing DFT for channel estimation of a time domain to obtain channel estimation of a frequency domain. The channel estimation perform is improved, the pilot frequency is of a comb-like pilot frequency structure, and rapid fading of short wave signals is effectively restrained.

Description

technical field [0001] The invention relates to the technical field of short-wave OFDM system communication, and specifically designs a channel estimation method for the short-wave OFDM system, in particular to a channel estimation method for the short-wave OFDM system under narrow-band interference. . Background technique [0002] Shortwave is a communication system that communicates with electromagnetic waves operating in the 1.5-30MHz frequency band. Shortwave communication has the capability of long-distance communication without relays, and has the advantages of strong mobility, fast network reconstruction, strong invulnerability, and strong confidentiality. Therefore, Short-wave communication is widely used in military, meteorological, aviation, navigation, emergency rescue and disaster relief and other fields. However, the shortwave communication channel has narrow frequency band, serious fading and multipath interference, and frequency selective fading, so the intro...

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Application Information

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IPC IPC(8): H04L25/02H04L27/26
Inventor 韦世红周小宇唐宏孟婷婷王飞薛真真
Owner CHONGQING UNIV OF POSTS & TELECOMM
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