OFDM Receiver Interpolation for Accurate Propagation Delay Measurement
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Solution Overview
Problem
Interpolation in OFDM systems can lead to false power peaks in delay profiles, causing incorrect measurement of propagation delay time, especially when the number of channel estimation values is not a power of 2.
Innovation Solution
A receiver device and method that interpolates channel estimation values to make them a power of 2, transforms them into the time domain, and detects power peaks while considering signal power to accurately measure propagation delay time, avoiding false peaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If interpolation is performed on channel estimation values to make the number of samples a power of 2, then the channel estimation can be completed, but false power peaks appear in the delay profile causing incorrect propagation delay time measurement
Solution Approach 1:
The patent extracts and removes the interpolated parts from the delay profile before performing power peak detection. By separating the interpolated components (which cause false peaks) from the actual signal components, the system can accurately identify true propagation delay peaks without interference from artificial peaks generated during interpolation.
Solution Approach 2:
The patent converts the harmful effect of interpolation (which creates false peaks) into a beneficial process by using the interpolated signal power information to identify and exclude false peaks. The same interpolation that causes the problem is used to solve it, by analyzing the power characteristics of interpolated regions to recognize and remove false peaks.
2Adaptability or versatility
If the number of channel estimation values is not a power of 2, then the system can handle variable data lengths, but interpolation is required which introduces false power peaks
Solution Approach 1:
The patent extracts and removes the interpolated parts from the delay profile before performing power peak detection. By separating the interpolated components (which cause false peaks) from the actual signal components, the system can accurately identify true propagation delay peaks without interference from artificial peaks generated during interpolation.
Solution Approach 2:
The patent introduces an intermediary step of calculating signal power for interpolated parts as a mediator between the interpolation process and the peak detection process. This intermediary power calculation serves as a criterion to distinguish true peaks from false peaks, enabling accurate measurement despite the presence of interpolation-induced artifacts.
Data Source
AI summary
A receiver device is provided with: channel estimation unit which obtains channel estimation values for a frequency domain on the basis of pilot symbols disposed in an OFDM subcarrier; interpolation unit which performs interpolation so that the number of samples of channel estimation values obtained by the channel estimation unit is a power of 2; transformation unit which transforms the channel estimation values interpolated by the interpolation unit into a time domain to obtain a delay profile; and power peak position detection unit which detects a power peak position of the delay profile so as to obtain a propagation delay time. The power peak position detection unit references the signal power of the portion interpolated by the interpolation unit in order to detect a suitable power peak position in the delay profile.