Receiving Device Frequency Error Estimation via Symbol Phase Difference
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Solution Overview
Problem
The challenge is to suppress the influence of intersymbol interference on frequency errors in synchronization signals within receiving apparatuses, particularly in satellite broadcasting systems, where using filters with low roll-off rates increases circuit complexity and costs, and reduces synchronization performance.
Innovation Solution
A receiving apparatus and method that includes an estimation unit for calculating the frequency error of synchronization signals and a control unit to manage intersymbol interference, using phase differences between symbols to minimize interference effects, allowing for accurate frequency synchronization with a reduced number of filter taps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a filter with a low roll-off rate is used on the receiving side to match the transmitting side, then transmission efficiency is improved, but the number of taps of the filter increases and circuit scale increases
Solution Approach 1:
The patent changes the parameter of frequency error estimation by using phase difference between symbols separated by a specific distance (e.g., 3 symbols) rather than adjacent symbols. This parameter change allows accurate frequency error detection without requiring a large number of filter taps, thus resolving the contradiction between transmission efficiency and circuit scale.
2Productivity
If a filter with a low roll-off rate is used on the receiving side to match the transmitting side, then transmission efficiency is improved, but loop delay of the synchronous loop becomes long and synchronization performance deteriorates
Solution Approach 1:
The patent changes the estimation method parameter from using adjacent symbols to using symbols separated by a distance of 2 or more. This parameter change enables accurate frequency error estimation with a reduced number of filter taps, thereby shortening the loop delay and improving synchronization performance while maintaining transmission efficiency.
3Device complexity
If the number of taps of the filter in the receiving apparatus is reduced to decrease circuit scale, then circuit complexity is reduced, but a component based on intersymbol interference cannot be removed and frequency error detection accuracy deteriorates
Solution Approach 1:
The patent converts the harmful effect of intersymbol interference into a beneficial estimation method. By using phase difference between symbols separated by a specific distance (accounting for ISI effects), the patent achieves accurate frequency error detection even with a reduced number of filter taps, thus resolving the contradiction between circuit complexity and measurement precision.
Solution Approach 2:
The patent changes the parameter of symbol distance used for phase difference calculation to 2 or more. This parameter change enables the system to accurately estimate frequency error while suppressing intersymbol interference components, achieving both reduced circuit complexity and maintained measurement precision.
4Measurement precision
If symbols separated by a distance of 2 or more are used for frequency error estimation, then intersymbol interference influence is suppressed, but more symbols are required for estimation
Solution Approach 1:
The patent optimizes the parameter of symbol distance to specifically 2 or more (preferably 3 or more, and odd numbers). This parameter setting achieves effective suppression of intersymbol interference while requiring a reasonable number of symbols for estimation, resolving the contradiction between measurement precision and quantity of symbols required.
Data Source
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AI summary
The present technology relates to a receiving apparatus and method, and a demodulating apparatus capable of suppressing influence exerted by intersymbol interference on a frequency error of a synchronization signal. An estimation value of the frequency error of a symbol included in the synchronization signal is estimated, and a component based on the intersymbol interference of the estimation value is controlled. For example, the estimation value can be estimated from a phase difference between two symbols. For example, a distance between the two symbols can be set to two or more. For example, a symbol for detecting the phase difference can be selected for the estimation value such that the component of the intersymbol interference is suppressed. For example, the component based on the intersymbol interference of the estimation value can be controlled by subtracting a value corresponding to the component of the intersymbol interference stored in advance.