OTFS Signal Demodulation Using Dual Reference Signals
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Solution Overview
Problem
Current methods for demodulating orthogonal time frequency space (OTFS) signals require a large amount of calculation, which hinders maintaining high data rates, especially in high-speed communication scenarios where Doppler effects are significant.
Innovation Solution
A wireless communication device and system that perform channel estimation using a first reference signal and phase correction using a second reference signal to demodulate OTFS signals, reducing computational complexity by separating channel correction in the frequency time space and phase correction in the Delay Doppler space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of reference signals is increased to correct Doppler effect in OFDM, then Doppler tolerance is improved, but the data rate lowers due to reduced data elements
Solution Approach 1:
The patent replaces OFDM's frequency-domain approach with OTFS modulation that operates in the Delay-Doppler domain. This substitution fundamentally changes how channel estimation works, allowing reference signals to be placed sparsely in the Delay-Doppler grid rather than densely in frequency, thereby maintaining high data rates while achieving robust Doppler tolerance.
Solution Approach 2:
The patent changes the fundamental parameters of signal arrangement from frequency-time (OFDM) to delay-Doppler (OTFS) domain. This parameter transformation enables the system to achieve high Doppler tolerance without sacrificing data rate, as the channel characteristics are captured more efficiently in the Delay-Doppler domain.
2Reliability
If channel estimation is frequently updated to correct Doppler effect, then Doppler tolerance is improved, but the amount of calculation for processing data increases
Solution Approach 1:
The patent performs channel estimation using reference signals placed at specific intervals in the Delay-Doppler domain. By pre-estimating the channel characteristics in this domain, the system avoids the need for frequent updates during data transmission, reducing computational complexity while maintaining accurate channel knowledge for Doppler correction.
Solution Approach 2:
The patent substitutes the frequent time-domain channel estimation updates with a single Delay-Doppler domain estimation approach. This substitution dramatically reduces the calculation amount required for channel correction while maintaining effective Doppler compensation.
3Measurement precision
If reference signals are arranged frequently in OTFS to obtain accurate CIR, then channel estimation accuracy is improved, but the data rate lowers due to reduced data elements
Solution Approach 1:
The patent applies local quality by placing reference signals at specific, strategically chosen positions in the Delay-Doppler grid rather than uniformly throughout. This allows accurate channel estimation in the critical regions while maximizing the number of data elements in other regions, thereby maintaining high data rate.
Solution Approach 2:
The patent uses partial action by arranging reference signals only at necessary intervals rather than continuously. This partial arrangement provides sufficient channel estimation accuracy for effective Doppler correction while leaving more resources available for data transmission, thus maintaining high data rate.
4Measurement precision
If convolution operation is performed with correction coefficient to correct propagation channel in OTFS, then channel correction accuracy is improved, but the amount of calculation increases
Solution Approach 1:
The patent substitutes the computationally intensive convolution operation with element-wise multiplication in the Delay-Doppler domain. This substitution maintains channel correction accuracy while dramatically reducing the amount of calculation required, as the correction coefficients can be directly applied point-wise to the received signal.
Data Source
AI summary
To provide a wireless communication device, a system, a method, and a program capable of accurately demodulating an orthogonal time frequency space (OTFS) signal with a small amount of calculation while maintaining an OTFS signal of a high data rate. A wireless communication device according to the present disclosure includes a reception unit configured to perform channel estimation using a first reference signal, perform phase correction mainly using a second reference signal, and demodulate a received orthogonal time frequency space (OTFS) signal using results of the channel estimation and the phase correction.