IoT Primary Synchronization via Dual-Stage Correlation
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Solution Overview
Problem
Existing methods for acquiring time and frequency synchronization in wireless communication systems for IoT services over wide areas face challenges in battery consumption and synchronization acquisition performance, making them unsuitable for long-term operation.
Innovation Solution
A method and apparatus that samples the primary synchronization signal, performs down-sampling, and uses sliding auto-correlation, smoothing correlation, and fine cross-correlation to estimate sample timing and frequency offsets, effectively combining coarse and fine correlation methods for efficient synchronization acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the cross-correlation method is used to acquire time and frequency synchronization, then synchronization acquisition performance is improved, but battery consumption is increased
Solution Approach 1:
The patent segments the correlation process into two distinct stages: a first correlation operation performed at a first sampling rate to acquire coarse synchronization, and a second correlation operation performed at a second sampling rate (lower than the first) to refine synchronization. This segmentation allows the system to achieve accurate synchronization while reducing overall computational complexity and power consumption by performing the more intensive correlation operation at a reduced sampling rate after initial acquisition
Solution Approach 2:
The patent applies preliminary action by performing the first correlation operation at the higher sampling rate to initially acquire time and frequency synchronization before performing the second correlation operation. This preliminary synchronization acquisition enables the subsequent correlation to be performed at a lower sampling rate, thereby reducing power consumption while maintaining synchronization accuracy
2Use of energy by moving object
If the auto-correlation method is used to reduce battery consumption, then power usage is reduced, but synchronization acquisition performance deteriorates
Solution Approach 1:
The patent merges the advantages of both cross-correlation and auto-correlation methods by combining a first correlation operation (performed at a first sampling rate) with a second correlation operation (performed at a second sampling rate). This combination allows the system to achieve the power efficiency of auto-correlation while maintaining the synchronization acquisition performance of cross-correlation, effectively resolving the contradiction between power consumption and synchronization performance
3Measurement precision
If high sampling rate is used for accurate synchronization estimation, then measurement precision is improved, but computational complexity and power consumption increase
Solution Approach 1:
The patent applies dynamics by adaptively adjusting the sampling rate based on the synchronization acquisition stage. The system dynamically switches from a first sampling rate during initial synchronization acquisition to a second sampling rate for refinement, optimizing the balance between measurement precision and computational complexity at different stages of the synchronization process
Data Source
AI summary
A method and an apparatus for primary synchronization in the Internet of things. A receiver samples a primary synchronization signal into a digital signal to generate a first sampling signal and down sample a first sampling signal into a second sampling signal. The receiver estimates a first sample timing offset (STO) and a first frequency offset (FO) using the first sampling signal and the second sampling signal.