Detection and estimation method for fine synchronization of downlink primary synchronization signal in NB-IoT system

Abstract

The invention discloses a detection and estimation method for fine synchronization of a downlink primary synchronization signal in an NB-IoT system. The method comprises the following steps: step (1),acquiring a time domain sampling sequence by an air interface receiver by adopting a sampling rate of 1.92MHz; step (2), performing NPSS coarse synchronization estimation by a terminal receiver; andstep (3), performing second fine synchronization at the sampling rate of 1.92Msps according to time offset and frequency offset results estimated in the course synchronization in step (2), and carrying out self-correlation operation by using an NPSS sequence and a local sequence, wherein the local sequence is generated by using integer frequency offset, and accurate time offset and the integer frequency offset are determined according to a peak position maximum value. The method of the invention has the following beneficial effects: the fine synchronization is that a correlation operation is carried out after an accumulation operation is carried out, so that the storage capacity is reduced; the fine synchronization adopts a pipeline structure based on two adders and one multiplier, so thatthe calculation amount and the storage size are reduced; and the fine synchronization frequency offset estimation stores a group of local sequences and performs iterative updating to replace multiplegroups of local sequences, so that the storage capacity is reduced.

Description

technical field [0001] The invention relates to the technical field of cellular narrowband Internet of Things NB-IoT, in particular to a method for detecting and estimating fine synchronization of a downlink main synchronization signal in an NB-IoT system. Background technique [0002] NB-IoT technology is an emerging technology in the IoT field, which supports the cellular data connection of low-power devices in the wide area network. NB-IoT technology is a communication protocol newly defined for narrowband and low-speed business scenarios. Compared with the LTE protocol, it has a new design on the physical layer. For the downlink transmission signal of the base station, although the primary and secondary synchronization signals still use the ZC sequence, due to the change of the bandwidth and other parameters, the signal sequence and structure are relatively different. The detection of NB-IoT downlink signals has become one of the research hotspots. [0003] Since the N...

AI Technical Summary

Problems solved by technology

This algorithm needs to calculate the sequence values ​​of different starting positions and integer multiple frequency offsets each time, the sequence storage is large, and the algorithm complexity is high, which is not conducive to hardware implementation

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