Repetitive Synchronization Signal for CFO Correction in Ultra-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 method involving the generation and transmission of repetitive synchronization signals with specific repetitive characteristics, including first and second repetitive synchronization signals in the same subframe, along with messages indicating their repetition factors and positions, to enhance CFO correction in high-frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a legacy synchronization signal is used in super-high frequency band, then the system can maintain compatibility with existing protocols, but the Carrier Frequency Offset (CFO) estimation precision deteriorates due to increased Doppler effects and oscillator errors
Solution Approach 1:
The synchronization signal is segmented into multiple repetitive instances within the same subframe. Each repetition provides an additional opportunity for CFO estimation, effectively dividing the estimation task across multiple signal occurrences rather than relying on a single synchronization signal instance.
Solution Approach 2:
The synchronization signal is transmitted periodically with a specific repetition factor within the subframe. This periodic transmission creates multiple correlated signal instances that can be combined through correlation processing to enhance CFO estimation accuracy despite the high Doppler effects in super-high frequency bands.
2Productivity
If the center frequency is increased to a few GHz to tens of GHz for super-high frequency operation, then the available bandwidth and system capacity improve, but the Doppler effect and CFO values increase linearly, worsening synchronization accuracy
Solution Approach 1:
Multiple copies of the synchronization signal are transmitted within the same subframe according to a repetition factor. These copied signals serve as redundant references for CFO estimation, allowing the receiver to combine multiple copies to achieve accurate frequency offset correction despite the high center frequency operating conditions.
Solution Approach 2:
The repetitive synchronization signal structure enables feedback-based CFO estimation where each repetition provides additional information that can be used to refine the frequency offset estimate. The correlated reception of multiple repetitions allows the system to iteratively improve synchronization accuracy even as the center frequency increases.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for accurate detection and correction of CFO values in super-high frequency bands, improving synchronization in wireless access systems by increasing the estimation range of synchronization signals.
Implementation Method 1
the super-high frequency characteristics of the center frequency worsen the Doppler effect generated during movement of a User Equipment (UE) or the effects of a Carrier Frequency Offset (CFO) caused by an oscillator error
Data Source
AI summary
The present invention relates to a method for newly defining a synchronization signal to be used in an ultrahigh frequency band and acquiring downlink synchronization by using the synchronization signal, and a device for supporting the same. A method by which an eNode B (eNB) transmits a synchronization signal for compensating for a carrier frequency offset in a wireless access system supporting an ultrahigh frequency band, according to one embodiment of the present invention, can comprise the steps of: generating a first repetitive synchronization signal having a first repetitive characteristic; generating a second repetitive synchronization signal having a second repetitive characteristic; and transmitting the first repetitive synchronization signal and the second repetitive synchronization signal in the same subframe.