Chirp spread spectrum communication receiver time synchronization system and method

Abstract

The invention provides a Chirp spread spectrum communication receiver time synchronization system and method. A signal-to-noise ratio enhancement module of the system is used for modulus operation conducting, gain acquiring, delaying and combining, wherein phase differences among symbols are eliminated by means of the modular operation, and useful signals are enhanced by means of gain acquiring; acombined spread spectrum modulation module conducts spread spectrum modulation with a combined Chirp signal; and after a signal obtained after combined spread spectrum modulation, matched filtering receiving and signal-to-noise ratio enhancement is acquired, peak searching of a narrow-band pulse obtained after matched filtering is narrowed within a symbol period by means of a noise threshold setin a judgment module, and a peak searching module captures the moment when a peak is obtained in the symbol period to achieve time synchronization. According to the system and method, by adding the judgment module in a synchronization module, error synchronization moment judgment brought when actual synchronization and ideal synchronization have a difference of integer multiples of the symbol period is solved, and the timing precision is improved; and meanwhile, the complexity of an algorithm is reduced due to narrowing of the synchronization moment searching range.

Description

technical field [0001] The present invention relates to the field of low power consumption wide area network, and more specifically relates to a receiver time synchronization system and method of a Chirp spread spectrum communication system. Background technique [0002] Among the many wireless technologies related to the Internet of Things, LoRa technology in low power wide area network (LPWAN) has become a hot spot in recent years. LoRa is a long-distance wireless transmission scheme based on spread spectrum technology promoted by Semtech in the United States. The characteristics of power consumption, low cost, wide coverage, and large connection, and the spread spectrum technology is firstly applied in military communication because of its strong anti-interference ability, multi-access communication, good confidentiality, and anti-multipath interference. It has received great attention, and has gradually been promoted in civilian communications. [0003] There are four m...

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Problems solved by technology

Since then, some studies have introduced interference suppression technology into the CSS system, which has enhanced the anti-interference ability to a certain extent, but there is a defect in this method. When the actual synchronous sampling differs from the ideal synchronous sampling by an integer multiple of symbol periods, the sampling value is too high. This will lead to a misjudgment of the synchronization moment

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