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A Simplified Method for Coarse Synchronous Autocorrelation of NB-IoT Terminals

An autocorrelation and coarse synchronization technology, applied in the direction of synchronization devices, wireless communication, transmission systems, etc., can solve the problems of no repeated use of autocorrelation repeating parts, long calculation time, etc., to shorten cell search time, reduce calculation time, The effect of improving computational efficiency

Active Publication Date: 2021-03-26
BEIJING ZHILIANAN TECH
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Problems solved by technology

[0003] In order to solve the above technical problems, the purpose of the present invention is to provide a simplified method for NB-IoT terminal coarse synchronization autocorrelation, so as to solve the problem that the autocorrelation repetition part of each starting position point in the prior art solution is not reused, resulting in calculation time long question

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  • A Simplified Method for Coarse Synchronous Autocorrelation of NB-IoT Terminals

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[0024] A simplified method for NB-IoT terminal coarse synchronization autocorrelation, NB-IoT synchronization signal includes narrow-band primary synchronization signal NPSS (Narrow-band Primary Synchronization Signal) and narrow-band secondary synchronization signal NSSS (Narrow-band Secondary Synchronization Signal), wherein NPSS is used to complete time and frequency synchronization, and is sent on subframe 5 of each radio frame, occupying the last 11 symbols of the subframe;

[0025] Assume that the downlink signal sampling rate of the NB-IoT terminal is 1.92MHz, and the data rate is reduced to 240KHz after 8 times downsampling. There are 240 sampling points in one subframe, and each symbol has an average of 17 sampling points; assuming the autocorrelation interval Δ is 1 symbol, the autocorrelation CorrResult(tau) of the sampling point tau is calculated as follows:

[0026]

[0027] Where s(i)=+1 or -1, determined by the symbol index i, d is the signal of each sampling...

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Abstract

The invention discloses a simplified algorithm for coarse synchronization autocorrelation of an NB-IoT (Narrow Band Internet of Things) terminal, and the method comprises the steps: enabling the downlink signal sampling rate of the NB-IoT terminal to be 1.92 MHz, enabling the data rate to be reduced to 240 KHz after eight times of down-sampling, enabling one subframe to have 240 sampling points, and enabling each symbol to have 17 sampling points on average, wherein the autocorrelation interval delta is one symbol, the autocorrelation calculation formula of the sampling point tau can be obtained and a CorrResult (tau) is calculated, a formula (shown in the description) can be obtained at the same time during calculation of the CorrResult (tau), and after the CorrResult (tau) is obtained,the CorrResult (tau+1) can be obtained only by executing complex conjugate multiplication for 10 times. According to the NB-IoT terminal coarse synchronization autocorrelation simplified algorithm, the problem of long operation time caused by the fact that the autocorrelation repeated part of each starting position point is not repeatedly utilized in the existing technical scheme is solved.

Description

technical field [0001] The invention relates to a simplified method for NB-IoT terminal coarse synchronization autocorrelation. Background technique [0002] The NB-IoT terminal first needs to complete the rough synchronization of NPSS in the cell search phase. Since the autocorrelation needs to be calculated for each sampling point within 10ms, the calculation amount required for the rough synchronization is large, and it takes a long time, which not only affects the terminal access time, but also It will affect the battery life of the terminal. Therefore, it is very meaningful to study the simplified algorithm of coarse synchronization. However, in the prior art, the autocorrelation is calculated for each starting position point in a wireless frame, and the repeated parts of the autocorrelation of each starting position point are not reused, and the calculation time is long. Contents of the invention [0003] In order to solve the above technical problems, the purpose ...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04B1/7083H04W56/00
CPCH04B1/7083H04W56/001
Inventor 杨澍宁吕悦川钱炜
Owner BEIJING ZHILIANAN TECH