Channel estimation methods based on decision feedback in shortwave narrowband FFH/BFSK system

A technology of channel estimation and decision feedback, applied in baseband system components, shaping network in transmitter/receiver, multi-frequency code system, etc., can solve problems such as demodulation influence, achieve simplified calculation complexity, and save resources The effect of spending

Inactive Publication Date: 2009-10-14
UNIV OF ELECTRONIC SCI & TECH OF CHINA
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Problems solved by technology

[0003] Frequency hopping communication systems mostly use M-ary frequency shift keying modulation (MFSK), and channel fading will affect demodulation

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  • Channel estimation methods based on decision feedback in shortwave narrowband FFH/BFSK system
  • Channel estimation methods based on decision feedback in shortwave narrowband FFH/BFSK system
  • Channel estimation methods based on decision feedback in shortwave narrowband FFH/BFSK system

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Embodiment Construction

[0030] The main innovation of the channel estimator of the present invention is to perform independent channel estimation for each sub-channel, and use decision feedback to iterate directly, which reduces pilot overhead and computational complexity, making it suitable for FFH / BFSK systems. Channel estimation can be implemented programmatically.

[0031] Computer simulation shows that 32 frequency hopping frequency points are taken, the frequency hopping interval is 20kHz, the frequency hopping frequency is 5000 hops / second, 1 bit data is sent per hop, and when the sampling rate is 1.28M, the LS decision feedback adopts sending a group every 2560 hops (64 hops ) pilot, the LMMSE decision feedback uses 640 hop pilots every 12800 hops. Compared with the perfect estimation, the performance difference between the two methods is about 1dB. Compared with the demodulation without channel estimation, both have about 5db performance improve.

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Abstract

The invention mainly provides two channel estimation methods of a shortwave narrowband FFH / BFSK system, including a least square (LS) method based on decision feedback and a linear minimum mean-square error (LMMSE) method based on the decision feedback. The two methods both independently estimate sub-channels and use the decision feedback for direct iteration.

Description

technical field [0001] The invention belongs to the technical field of communication anti-jamming, in particular to a short-wave narrowband FFH / BFSK system. Background technique [0002] Because of its mature technology, long communication distance, small size, and suitable for working on mobile platforms, short-wave communication has become one of the main means of communication in national defense scientific research experiments. [0003] Frequency hopping communication systems mostly use M-ary frequency shift keying modulation (MFSK), and channel fading will affect demodulation. Channel estimation aims to obtain channel fading parameters in advance before demodulating received signals, and compensate during demodulation to reduce the judgment error rate caused by channel fading. [0004] At present, the research on channel estimation is mainly under the Orthogonal Frequency Division Multiplexing (OFDM) system. There are few articles on channel estimation of the short-wav...

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Application Information

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IPC IPC(8): H04L25/02H04L25/03H04L27/26
Inventor 叶俊龙程郁凡李少谦周志强
Owner UNIV OF ELECTRONIC SCI & TECH OF CHINA
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