Carrier synchronization method of burst direct sequence spread spectrum system

Abstract

The invention discloses a carrier synchronization method of a burst direct sequence spread spectrum system, which is mainly used for solving the problems of low carrier bias estimation precision and small carrier bias estimation range in the traditional DSSS (Direct Sequence Spread Spectrum) communication system carrier synchronization technology. The carrier synchronization method comprises the following steps of: firstly, carrying out coarse estimation on carrier frequency offset and phase offset through a pilot frequency assistance-based average periodogram method and an ML (Multi-Lag) phase offset estimation method; secondly, determining a frequency offset fine estimation interval of each iteration during fine estimation; and in the frequency offset fine estimation interval of each iteration, searching by using maximizing despread output information mean square value as a rule to obtain accurate estimation values of carrier frequency offset and phase offset, and realizing carrier synchronization of a DSSS system. The invention can be used for correcting a large carrier offset by using less pilot frequency overhead, realizes effective carrier synchronization, obtains an approximately perfect bit error rate, and is suitable for a burst DSSS communication system.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and further relates to a carrier synchronization method of a burst direct sequence spread spectrum (Direct Sequence Spread Spectrum, DSSS) signal in digital communication, which can be used for a burst DSSS system with a large frequency in an extremely low signal-to-noise ratio environment. Estimation and compensation of partial and large partiality. Background technique [0002] Compared with other communication systems, the burst DSSS system has an extremely low transmit power spectral density, so that useful signals are completely buried in the noise, that is, it works at an extremely low signal-to-noise ratio, which reduces the probability of being intercepted, and thus has good security sex. In addition, the burst DSSS system also has strong anti-interference characteristics and strong selective addressing capabilities, and has incomparable advantages in anti-interference and...

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: when the carrier frequency offset is in the middle of the two spectral lines, the performance will decrease; Significant performance degradation; estimation accuracy is not high enough at high data rates

The disadvantages of this invention are: the frequency offset capture range is small, the carrier phase offset cannot be estimated, and it cannot meet the requirements of high data rate and large frequency offset phase offset burst DSSS system

Although this method can achieve accurate synchronization and correct decoding under extremely low signal-to-noise ratio, it cannot be applied to communication systems with large frequency deviation and large phase deviation because the estimation range of carrier synchronization is very small.

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