Frequency Offset Correction in V2V Communication Using Comb-Type Reference Signals
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Solution Overview
Problem
Vehicle-to-vehicle (V2V) communication in wireless communication systems faces challenges due to high-speed vehicle movement, leading to low reliability caused by the Doppler effect and rapidly changing channel states, necessitating a method to correct frequency offsets for stable communication.
Innovation Solution
A method for correcting frequency offsets in V2V communication by receiving a subframe with a reference signal, mapping it to resource elements with specific subcarrier indices, and comparing repeated signals using Fast Fourier Transform (FFT) or half-FFT to apply the correction to the user equipment (UE), utilizing a demodulation reference signal (DMRS) sequence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequency offset correction is performed using conventional methods in V2V communication, then communication can be maintained, but reliability is low due to high-speed vehicle movement causing Doppler effect and rapidly changing channel states
Solution Approach 1:
The patent applies preliminary action by performing frequency offset correction using reference signals before actual data transmission and reception. The method estimates frequency offset using reference signals that are transmitted in advance, allowing the receiver to compensate for Doppler effects before the harmful impact degrades communication reliability.
Solution Approach 2:
The patent replaces mechanical frequency synchronization methods with signal processing-based frequency offset estimation and correction. Instead of relying on mechanical frequency locking, the system uses FFT-based correlation of reference signals to estimate and correct frequency offsets, which is more effective in high-speed mobile environments with rapid channel changes.
2Measurement precision
If reference signals are transmitted frequently to improve channel estimation, then channel estimation performance improves, but reference signal overhead increases
Solution Approach 1:
The patent applies partial action by using only the necessary portion of reference signals for frequency offset estimation. Instead of transmitting full reference signals across all resource elements, the method extracts frequency offset information from specific reference signal positions, achieving sufficient channel estimation precision while minimizing reference signal overhead.
Solution Approach 2:
The patent extracts frequency offset information from reference signals without requiring the entire reference signal structure. By taking out only the essential frequency offset estimation function from the complete reference signal, the system achieves accurate channel estimation while reducing the quantity of reference signals that need to be transmitted.
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 improves channel estimation performance while maintaining reference signal overhead, enhancing the reliability and stability of V2V communication by effectively addressing frequency offset issues.
Implementation Method 1
comparing repeated signals repeated at a time interval corresponding to a first symbol among the four symbols... by performing a Fast Fourier Transform (FFT) or a half-FFT on the repeated signals
Data Source
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AI summary
A method for correcting frequency offset in vehicle-to-something (V2X) communication is disclosed. In order to correct the frequency offset in V2X communication, a comb-type reference signal is mapped on four symbols within a subframe. The frequency offset can be corrected on the basis of the comb-type reference signal, by comparing repetitive signals appearing in one symbol.