Time of Arrival Estimation via Channel Impulse Response Peak Detection
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Solution Overview
Problem
Current indoor navigation methods, such as Time-of-Flight (ToF) measurement, face challenges in accurately calculating the time of arrival (ToA) of signals, leading to inaccurate distance estimation due to potential inaccuracies in ToA calculations.
Innovation Solution
A method and system that involve sampling a wireless signal, performing a fast Fourier transform (FFT) to convert data to a frequency domain, dividing by a reference signal to obtain a discrete channel frequency response, and then using an inverse discrete Fourier transform (IDFT) to determine a peak in the discrete channel impulse response, thereby accurately calculating the ToA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional ToA calculation methods are used, then the process is simple, but the measurement precision is poor
Solution Approach 1:
The patent extracts the dominant path signal from multipath signals by performing FFT to convert to frequency domain, dividing by reference signal to obtain channel frequency response, then IDFT to get channel impulse response. The peak detection in the impulse response isolates the direct path ToA from reflected paths, achieving high precision by separating the desired signal component from interference.
Solution Approach 2:
The patent performs preliminary signal processing steps before final ToA determination: sampling the received signal, applying FFT to transform to frequency domain, dividing by reference signal to compensate for channel effects, and performing IDFT to obtain impulse response. These preliminary actions prepare the signal in an optimal form for accurate peak detection and ToA calculation.
2Measurement precision
If FFT and IDFT processing is performed, then the ToA accuracy is improved, but the processing time increases
Solution Approach 1:
The patent changes the domain parameter of the signal from time domain to frequency domain via FFT, processes the signal in frequency domain by dividing with reference signal, then transforms back to time domain via IDFT to obtain impulse response. This parameter transformation enables accurate ToA measurement while the efficient FFT/IDFT algorithms minimize processing time overhead.
3Measurement precision
If channel impulse response analysis is used, then the ToA determination accuracy is enhanced, but the device complexity increases
Solution Approach 1:
The patent replaces direct time-domain correlation methods with a frequency-domain processing approach using FFT and IDFT. This substitution leverages the computational efficiency of FFT algorithms and the mathematical properties of channel frequency response to achieve accurate impulse response estimation without requiring complex time-domain filtering or correlation operations.
Data Source
AI summary
A method of determining a time of arrival (ToA) of a wireless transmission includes: sampling a signal received in a wireless transmission to generate first data in a time domain, performing a FFT on the first data to generate second data in a frequency domain, dividing the second data by a reference signal to obtain a channel frequency response, performing and IDFT on the channel frequency response to obtain a channel impulse response, determining a peak in the channel impulse response; and determining the ToA based on the peak.