Method and system for determining cell ID in NSSS synchronization process of NB-IoT system

Abstract

The present invention relates to a method and a system for determining a cell ID in the NSSS synchronization process of an NB-IoT system. The method comprises the following steps: 1, acquiring an NSSSsequence according to an NPSS timing position, wherein the NSSS sequence includes multiple NSSS subsequences; 2, making four autocorrelation operations on two NSSS subsequences with a sliding interval of 1, and acquiring four energy peak values which correspond to different q values; 3, comparing the four energy peak values respectively, determining the maximum energy value of the four energy peak values, and obtaining the q value corresponding to the maximum energy value and the position of the maximum energy value in a time domain; 4, performing calculation according to the position in conjunction with a Fourier transform property to obtain a u value; and 5, performing calculation according to the q value and the u value to obtain a cell ID. The technical scheme of the invention can reduce the computational complexity in determining the cell ID and improve the synchronization efficiency of NSSS.

Description

technical field [0001] The present invention relates to the technical field of Internet of Things communication, and in particular to a method and a system for determining a cell ID during NSSS synchronization of an NB-IoT system. Background technique [0002] Narrow Band Internet of Things (NB-IoT) is an important branch of the Internet of Things, which has the characteristics of low speed, wide coverage and low power consumption. In the scenarios of low speed transmission, low power consumption and low mobility There are a wide range of applications. [0003] In the NB-IoT communication system, after the mobile terminal equipment is powered on, it needs to establish a downlink connection with the cell base station. When establishing a downlink connection, an initial cell search is first required. During the initial cell search, the mobile terminal device uses the downlink primary synchronization signal NPSS to complete time and frequency synchronization, and uses the prim...

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Problems solved by technology

[0004] In the NB-IoT communication system, there are a total of 504 cell ID numbers to uniquely identify each cell in the system. In the prior art, the blind detection algorithm is usually used to determine the cell ID, and the idea of ​​exhaustive method is used, but The blind detection algorithm has the disadvantage of low efficiency in searching cell IDs, which is mainly reflected in the following two aspects: first, there are a large number of 504 cell IDs that need to be traversed completely, and it takes a long time; second, the number of cross-correlation operations More, in the process of traversing 504 cell IDs, 504 local NSSS sequences will be generated, so it is necessary to perform 504 cross-correlation operations on the local NSSS sequences and the NSSS frequency domain signals sent by the base station to the terminal, and the calculation complexity is high

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