Aperiodic long-code direct sequence spread spectrum signal time delay estimation method and system based on norm fitting

Abstract

The invention belongs to the technical field of signal processing, and particularly relates to an aperiodic long-code direct sequence spread spectrum signal time delay estimation method and system based on norm fitting, and the method comprises the steps: carrying out the carrier synchronization and timing synchronization of a received signal, and obtaining an aperiodic long-code direct sequence spread spectrum CDMA baseband waveform; modeling the long code direct sequence spread spectrum signal into a short code direct sequence spread spectrum signal containing missing observation, rearranging the baseband waveform into a missing data matrix according to the code element width of the information code, and obtaining an F norm curve of the missing data matrix; setting an equivalent period,representing the missing data matrix as cyclic repeat representation of a cellular matrix, and obtaining a user signal F norm curve square template according to the cellular matrix and the screening matrix; and modeling the multi-user signal F norm curve as cyclic convolution of a template curve, and solving the model by using a least square method to obtain an out-of-step time parameter of each user. According to the method, the time delay estimation of the high-capacity asynchronous NPLCDSSSCDMA system under the non-cooperative receiving condition can be realized, and the operation complexity of the system is effectively reduced while the good estimation precision is ensured.

Description

technical field [0001] The invention belongs to the technical field of signal processing, in particular to a method and system for estimating time delay of non-periodic long code direct spread signal based on norm fitting. Background technique [0002] Direct Sequence Spread Spectrum (DSSS) signals are widely used in many important communication occasions, such as a large number of commercial communications, because of their remarkable security. At the same time, it also has excellent anti-interference and multiple access capabilities, especially good anti-channel fading performance, which makes its application scenarios continue to expand. In recent years, it has gradually been applied to strong interference systems such as mobile communications and underwater communications. The DSSS transmitter uses a pseudo-random sequence to modulate the transmission sequence, which reduces the transmission power while spreading the spectrum, making the received signal appear like Gauss...

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Problems solved by technology

For NPLC-DSSS signals, because the waveform in the pseudo code period is randomly modulated by the information symbols, when the period is segmented, the F norm of the signal correlation matrix under the same symbol cannot be accumulated, so this method cannot be directly applied. The research results of user blind synchronization technology are very limited, and there is no reliable solution for large-capacity NPLC-DSSS-CDMA system blind synchronization

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