Pulse Interference Suppression Device and Method for Direct Sequence Spread Spectrum System

Abstract

The invention discloses a pulse interference suppression device for a direct sequence spread spectrum system, which comprises a sequentially connected preprocessing module, a framing module, an autocorrelation matrix estimation module, a power normalization module and a sampling recovery module; the preprocessing module is used for Convert the received signal with a large amplitude change into a signal with a relatively constant envelope; the framing module is used to buffer the received signal; the autocorrelation matrix estimation module is used to obtain the autocorrelation matrix of the input signal vector through iterative estimation, and send it to The multiplier and the receiving vector are multiplied to obtain the signal after interference suppression; the power normalization module is used to perform power normalization processing on the signal after interference suppression; the sampling recovery module is used to convert the received signal after interference suppression processing The signal vector returns to the normal received signal. The invention has obvious interference suppression ability under high interference-to-signal ratio, has the characteristics of low complexity and is not restricted by scrambling codes, and is more practical in real systems.

Description

technical field [0001] The invention relates to a direct sequence spread spectrum communication system, in particular to a direct sequence spread spectrum system pulse interference suppression device and method. Background technique [0002] The direct sequence spread spectrum system is one of the most widely used digital communication systems at this stage. It has many advantages such as strong anti-multipath ability, low transmission power, low interception rate, and good confidentiality. It is widely used in military communications, satellite communications and mobile communications. been widely used in. Impulse interference is one of the main interferences existing in the current direct sequence spread spectrum system. In the past 20 years, a lot of research work mainly focused on interference suppression methods such as interference prediction and cancellation and transform domain filtering. [0003] At present, common direct sequence spread spectrum communication syst...

AI Technical Summary

Problems solved by technology

[0008] (1) Time-domain prediction technology: Time-domain prediction technology is designed based on the assumption that the interference can be predicted. When the interference is a random pulse signal, this assumption is often not satisfied. Therefore, the time-domain prediction technology suppresses random pulse interference. poor performance

Moreover, the direct spread spectrum signal is not random, so in order to achieve better suppression performance, the prediction technology must introduce a nonlinear correction function, which will increase the system overhead

[0009] (2) Transform domain technology: the problem of transform domain technology is spectrum leakage and useful signal loss

Spectrum leakage can be suppressed to a certain extent by windowing, but at the same time, windowing causes distortion of useful signals

Since the transform domain method suppresses the interference by deleting and clipping excessive spectral lines, the useful signal is inevitably lost during the suppression process. When the pulse interference is a monotone interference or a chirp signal, this loss can be ignored , but when the interference is a random pulse interference with a relatively large bandwidth, the useful signal loss caused by spectral line processing will have a great impact on system performance

[0010] (3) Code-assisted technology: fixed code-assisted technology requires prior information of the interference signal, which is inconvenient to implement in actual systems

However, the performance of adaptive code-assisted technology is not ideal, and the amount of calculation is too large when dealing with the autocorrelation matrix whose dimension is the spreading factor

In addition, the code-assisted technology needs to be carried out under the condition that the received signal is already synchronized. In the case of high pulse strength, the system often cannot be synchronized smoothly.

Moreover, in engineering implementation, due to the use of fixed-point processing, when there is a large-intensity pulse interference, it may cause system overflow and poor system stability.

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