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Air interface time frequency synchronization method for NB-IoT system

A technology of time-frequency synchronization and processing steps, which is applied in the field of communication, can solve the problems of increasing the length of related data and speeding up calculation speed, and achieve the effect of good correlation, speed up calculation speed and strong environmental use ability

Active Publication Date: 2017-11-07
NANJING TRANSCOM INFORMATION TECH CO LTD
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Problems solved by technology

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a time-frequency synchronization method in a complex electromagnetic environment, which uses the algorithm of joint detection of primary synchronization and secondary synchronization to make the length of relevant data longer and make it more accurate in synchronous data In the case of noise interference, it has a good correlation; at the same time, it adopts the method of speed reduction and frequency conversion, which speeds up the calculation speed, reduces the hardware resource overhead, enhances the real-time performance of the algorithm, and has a strong ability to use the environment

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  • Air interface time frequency synchronization method for NB-IoT system

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Embodiment 1

[0037] see Figure 1 ~ Figure 3 , a NB_IoT system air interface time-frequency synchronization method of the present invention is characterized in that the following processing steps are adopted:

[0038] a. Extract the I / Q data of two wireless frames 11ms after A / D sampling at the receiving end to ensure that a complete NPSS channel data can be obtained, and reduce the speed through a digital filter to perform 1 / 8 or 1 / 16 or 1 / 32 times extraction processing to generate a new data sequence:

[0039] r filter (m)=I'(m)+j*Q'(m) m=0, 1, . . . , 21119 (1),

[0040] Wherein, I ' (m) is the I road data after the deceleration, and Q' (m) is the Q road data after the deceleration;

[0041] b. Generate local NPSS signals according to formula (1), and generate time-domain data of different symbol positions through Fourier transform of 256 points or 128 points or 64 points:

[0042]

[0043] Where u is the root sequence index of Zadoff-Chu, l is the position where the primary syn...

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Abstract

The invention relates to the technical field of communication, in particular to an air interface time frequency synchronization method for an NB-IoT system. The method adopts a main synchronization and secondary synchronization joint detection algorithm, so that the length of related data becomes longer, and the correlation is good when the synchronous data is disturbed by noise; and meanwhile, through adoption of a speed reduction and frequency conversion way, the computation speed is accelerated, the cost of hardware resources is reduced, the real-time performance of algorithm implementation is enhanced, and the environment use ability is stronger.

Description

technical field [0001] The present invention relates to the technical field of communication, in particular to an air interface time-frequency synchronization method of an NB_IoT system in a complex electromagnetic environment. Background technique [0002] The Internet of Things is used in all aspects of production and life, and its business has different requirements for network transmission rates. High-speed services mainly use 3G and 4G technologies, such as surveillance cameras, etc.; medium-speed services mainly use GPRS technology, such as POS machines. There is no good cellular technology to meet the low-speed business at present, and in many cases, it can only be supported by GPRS technology. With the development of the Internet of Things, low-speed services have gradually become the main market development direction of the cellular Internet of Things in the future. The industry classifies this market as the LPWAN (Low Power Wide Area Network) market, that is, the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04J3/06H04L5/00H04W56/00
CPCH04J3/0605H04L5/0048H04W56/001
Inventor 陈向民
Owner NANJING TRANSCOM INFORMATION TECH CO LTD