Repetitive Synchronization Signal for CFO Estimation in Super-High Frequency Bands
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Solution Overview
Problem
Super-high frequency wireless access systems face challenges in accurately detecting and correcting Carrier Frequency Offset (CFO) due to increased Doppler effects, which existing synchronization signals struggle to address effectively.
Innovation Solution
A new synchronization signal is defined and transmitted in a super-high frequency band, using a repetitive synchronization signal with a repetition factor to estimate and correct CFO, where the signal is sent in two frames with a message indicating the repetitive sequence bitmap and repetition factor, allowing for accurate CFO estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a legacy synchronization signal is used in super-high frequency band, then the system can operate at higher frequencies, but the CFO estimation accuracy deteriorates due to increased Doppler effect and oscillator error
Solution Approach 1:
The synchronization signal is segmented into multiple repetitive sequences within a frame. Each sequence provides independent CFO estimation opportunities, and the combined information from multiple sequences improves overall estimation accuracy despite the harsh super-high frequency conditions
Solution Approach 2:
The synchronization signal employs periodic repetition within each frame, where the same sequence is transmitted multiple times. This periodic structure enables the receiver to perform multiple CFO measurements and average them, thereby improving estimation accuracy in the presence of large Doppler effects and oscillator errors
2Device complexity
If the synchronization signal is transmitted without repetitive characteristic, then the signal structure is simpler, but the CFO estimation range is insufficient for super-high frequency band
Solution Approach 1:
The synchronization signal is designed with predetermined repetitive patterns before transmission. This preliminary structuring of repetition factors and sequence patterns enables the receiver to perform accurate CFO estimation without requiring complex adaptive processing, thus maintaining signal structure simplicity while ensuring sufficient estimation range
3Measurement precision
If a repetitive synchronization signal with repetition factor is used, then the CFO estimation accuracy is improved, but the signal transmission complexity increases
Solution Approach 1:
The system changes the repetition factor parameter of the synchronization signal based on the super-high frequency band requirements. By adjusting this single parameter, the signal provides sufficient CFO estimation range without requiring complete redesign of the signal structure, thus limiting the increase in transmission complexity
Data Source
AI summary
The present invention relates to a method for newly defining a synchronous signal used in a super-high frequency band and acquiring downlink synchronization by using the synchronous signal, and an apparatus for supporting the same. The method for enabling a base station to transmit the synchronous signal in the wireless access system supporting the super-high frequency band, as one embodiment of the present invention, comprises the steps of: generating a general synchronous signal which do not have repetitive characteristics; generating a repetitive synchronous signal on the basis of a repetition factor for estimating a carrier frequency offset of the super-high frequency band; transmitting the general synchronous signal from a first frame; and transmitting the repetitive synchronous signal from a second frame. At this time, the repetition factor indicates the repetitive characteristic of the repetitive synchronous signal.