Cell discovery method and device based on nb-iot system

Abstract

The embodiment of the invention provides a cell discovery method and apparatus based on an NB-IoT system. The method comprises the following steps: performing mutual correlation operation on narrowband sub-synchronous signals NSSS in received signals with q sequences in local signals to obtain first correlation values, determining a q value corresponding to the maximum first correlation value as a target q value, and determining a cell number range through the target q value; traversing each cell number within the cell number range, correspondingly generating a u value for each cell number, separately substituting the generated u values into a narrowband sub-synchronous signal NSSS generation formula to generate the narrowband sub-synchronous signals NSSS; performing mutual correlation operation on the generated narrowband sub-synchronous signals NSSS and the narrowband sub-synchronous signals NSSS in the received signals to obtain second correlation values, determining the u value corresponding to the maximum second correlation value as a target u value; and calculating the cell number corresponding to a base station that sends the received signals according to the target q value and the target u value. The scheme can improve the cell discovery efficiency.

Description

technical field [0001] The present invention relates to the technical field of Internet of Things communication, in particular to a cell discovery method based on the NB-IoT system and a cell discovery device based on the NB-IoT system. Background technique [0002] In the NB-IoT (Narrow Band Internet of Things) system, cell discovery is a very important part. The process of cell discovery is as follows: the base station transmits a cell identifier in each wireless frame, and the terminal implements it based on the cell identifier Cell discovery, cell discovery is actually the determination of the cell number, where the cell identifier includes: Narrowband Primary Synchronization Signal NPSS (Narrowband Primary Synchronization Signal) and Narrowband Secondary Synchronization Signal NSSS (Narrowband Secondary Synchronization Signal), the determination of the cell number and wireless The narrowband primary synchronization signal NPSS in the frame is related to the narrowband s...

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Problems solved by technology

In the prior art, the exhaustive method is usually used to determine the cell number. Although the process of the exhaustive method is relatively simple, the exhaustive method has the disadvantage of low cell discovery efficiency, which is mainly reflected in the following two aspects: the first aspect , the number of traversal cell numbers is large, and 504 cell numbers need to be traversed; the second aspect, the number of cross-correlation calculations is relatively large, and it generates 504 narrowband secondary synchronization signals NSSS during the process of traversing 504 cell numbers. Therefore, it is necessary to Perform 504 cross-correlation operations on the narrowband secondary synchronization signal NSSS and the narrowband secondary synchronization signal NSSS in the received signal sent from the base station to the terminal

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