Direct sequence spread spectrum (DSSS) communication pseudo code capture method used in wireless sensor network (WSN)

Abstract

The invention discloses a direct sequence spread spectrum (DSSS) communication pseudo code capture method used in a wireless sensor network (WSN). The method comprises the following steps: step 1. carrying out differential treatment to an input signal and a local pseudo code, using a circumferential related characteristic of FFT to perform parallel search pseudo code phase to the input signal and the local pseudo code after the differential treatment, adjusting the local pseudo code phase so that the local pseudo code phase is synchronized with the input signal pseudo code and completing the pseudo code phase capture; step 2. using the FFT to perform parallel search carrier frequency offset to the input signal and the local pseudo code after the pseudo code synchronization and completing frequency offset correction. By using the pseudo code capture method of the invention, search time can be shortened and a search speed can be increased. The capture time can not be increased as a length of the pseudo code is longer and carrier wave frequency offset is larger. A correlator does not needed during a capture process. Resource consumption is low. The method can be flexibly modified according to a requirement of a system to a signal to noise ratio.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and relates to a direct-spread communication pseudo-code acquisition method used in a wireless sensor network. Background technique [0002] Wireless Sensor Network (WSN) is an "intelligent" network composed of miniature sensor nodes with wireless communication, perception and computing capabilities. It is used in various fields such as military, agriculture, environmental testing, medical and health, industry, intelligent transportation, etc. In view of the harsh environment of wireless sensor network applications and the establishment of the IEEE802. , DSSS) technology has played a huge role and advantages in wireless sensor network communication. Since most nodes in wireless sensor networks are limited by resources, cost, and power consumption, DSSS communication applied in wireless sensor networks needs to meet the requirements of low resource consumption, large carrier frequ...

AI Technical Summary

Problems solved by technology

The biggest disadvantage of the pseudo-code phase serial-carrier frequency offset serial search and capture is that the capture time is too long. Since the pseudo-code phase and frequency offset are all serial searches, when the pseudo-code is longer and the frequency offset is larger capture time will be unbearable

Although the PMF-FFT acquisition method of pseudo-code serial-frequency offset parallel search can analyze the carrier frequency offset in parallel at one time, it can adapt to the scene of large frequency offset, but it searches serially for the pseudo-code phase, so when the pseudo-code is relatively When long, the capture time is still large

Pseudo-code phase parallel-carrier frequency offset serial search acquisition methods are divided into two types. One is that the pseudo-code phase parallel is completed by parallel correlators or matched filters. The number of parallel correlators increases with the code length. increase, the corresponding system overhead is very large; the other is to use FFT to complete the circular correlation principle to search for the pseudo code phase in parallel. Although this method saves resources, the frequency offset search is still serial, so in large In the case of frequency offset, the search time is very long, which makes the acquisition time longer

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