A Pulse Interference Suppression System for Rangefinders Based on Soft Symbol Reconstruction

Abstract

The invention discloses a range finder pulse interference suppression method based on soft symbol refactoring. The method comprises a radio frequency front end, an analog to digital converter, a cyclic prefix remover, a pulse extinguisher, an inter-subcarrier interference compensator, a fast Fourier converter, a down-sampler for obtaining a signal vector, a soft demodulator, a de-interleaver, a soft decoder and a hard decider which are connected in series according to a sequence. The radio frequency front end receives a radio frequency signal containing range finder pulse interference. The output end of the hard decider outputs an estimation value of a bit sequence. The output end of the analog to digital converter is also connected with the pulse extinguisher through a range finder interference detector and a pulse location estimator in sequence. The output of the soft decoder is connected with the input end of the inter-subcarrier interference compensator through an interleaver, a soft symbol refactoring device, a multiplier, an upper-sampler and a fast Fourier inverse converter in sequence. The output end of the down-sampler is also connected with the soft demodulator and the multiplier through a channel estimator. According to the method, the better link error transmission performance is realized, and the interference suppression effect is better.

Description

technical field [0001] The invention relates to a pulse interference suppression method. In particular, it relates to a method for suppressing pulse interference of a range finder based on soft symbol reconstruction. Background technique [0002] L-band digital aviation communication system 1 is an air-to-ground cellular mobile communication system deployed by civil aviation along land routes in the future. This system mainly provides air traffic control and airline operation management data communication services for aircraft on land routes, terminal areas and airports. The system is one of the main technical means of the civil aviation future aeronautical mobile communication system. According to the plan of the International Civil Aviation Organization, the L-band digital aviation communication system 1 system will be deployed in an embedded manner between the channels of the L-band rangefinder, occupying a transmission bandwidth of 500KHz. Due to the partial overlap of...

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Problems solved by technology

[0010] Although the pulse extinguishing method can eliminate the pulse interference directly and conveniently, in practical application, this method has the following two problems: the first problem is that the threshold of the pulse interference signal is not easy to determine, because the OFDM signal itself The peak-to-average ratio is high, and it is usually difficult for the receiver to determine the pulse extinction threshold, which will lead to a decrease in receiver performance

The second problem is that after the receiver uses pulse extinguishing, the OFDM receiver will generate inter-subcarrier interference, which will eventually lead to the deterioration of receiver performance.

[0011] The hard-decision iterative inter-subcarrier interference suppression method improves the reliability of link transmission by reconstructing inter-sub-carrier interference, but there are still two problems in this method: (1) the inherent limitations of the hard-decision iterative inter-subcarrier interference suppression method. Error propagation phenomenon; (2) The computational complexity of iterative inter-subcarrier interference reconstruction and compensation is high, and the convergence speed is slow

In practical application, this method has disadvantages: when the rangefinder interference is small, the orthogonal projection interference suppression performance is poor

In practical application, this method has the main disadvantage: when the received OFDM signal power is low and the data snapshots are few, the signal direction estimation performance of the proposed method is poor

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