Impulse Response Correction for Multipath Channel Monitoring
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Solution Overview
Problem
In digital broadcasting networks, especially in SFN (Single Frequency Network) systems, the impulse response of the propagation channel is not fixed over time due to changes in multipath conditions, leading to false alarms from monitoring equipment as paths shift within the observation window, necessitating a method to stabilize the impulse response and minimize false alarms.
Innovation Solution
A method that estimates and corrects the time shift and absolute level of the impulse response by calculating a correlation function and temporal matching between current and reference impulse responses, ensuring peaks remain stable over time and adjusting for level variations, thereby stabilizing the impulse response and reducing false alarms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the impulse response is monitored in a multipath propagation channel, then the propagation conditions can be tracked, but false alarms occur due to path shifts within the observation window
Solution Approach 1:
The patent implements a feedback mechanism where the estimated time lag from the previous iteration is used to pre-shift the current impulse response before correlation processing. This feedback loop continuously adapts to path shifts and prevents false alarms by maintaining stable peak positions in the corrected impulse response
Solution Approach 2:
The patent applies preliminary action by estimating the time lag between iterations and performing a pre-shifting operation on the current impulse response before correlation processing. This preliminary adjustment prevents path shifts from causing false alarms during monitoring
2Productivity
If the CIR is positioned within the observation window based on the weighted center of gravity, then demodulation is optimized, but peak positions shift over time causing false alarms
Solution Approach 1:
The patent uses feedback by continuously estimating the time lag between iterations and applying corrective pre-shifting to maintain stable peak positions. This feedback mechanism allows the system to preserve demodulation efficiency while preventing peak position drift that causes false alarms
Solution Approach 2:
The patent changes the time lag parameter dynamically between iterations based on estimated path shifts. By adjusting this parameter and applying pre-shifting, the system maintains both demodulation efficiency and peak position stability simultaneously
3Measurement precision
If monitoring equipment sets presence alarms on specific paths, then transmitter status can be tracked, but path shifts cause false alarm triggering
Solution Approach 1:
The patent applies preliminary action by estimating the time lag and performing pre-shifting on the impulse response before correlation processing. This preliminary adjustment ensures that path positions remain stable within the observation window, allowing presence alarms to accurately detect transmitter status without false triggering
Solution Approach 2:
The patent implements feedback by using the estimated time lag from previous iterations to continuously adjust and stabilize path positions. This feedback mechanism maintains both accurate path detection and reliable alarm triggering by preventing position drift
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
The method effectively stabilizes the impulse response, reducing false alarms by maintaining peak positions and adjusting for level changes, thus enhancing the reliability of monitoring systems in dynamic multipath environments.
Implementation Method 1
calculating a correlation function and temporal matching between current and reference impulse responses
Data Source
Figure 1a~6
Figure 2a~2c
Figure 3a~3d
AI summary
The invention relates to a method for correcting the impulse response of a multipath propagation channel. Such a method comprises at least one iteration of the following steps: - obtaining (E300) a current impulse response of the propagation channel; - estimating (E310) a time offset between the current impulse response and a reference impulse response of the propagation channel; and - correcting (E320) the current impulse response based at least on the time offset, delivering a corrected impulse response.