Symbol Synchronization Fastest Path Detection Multipath
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Solution Overview
Problem
Conventional symbol synchronization methods in digital signal reception systems, particularly in OFDM systems, fail to accurately estimate symbol timing in multipath environments, leading to significant symbol timing errors and Inter-Symbol Interference (ISI) due to the dominance of the strongest path, which masks the first path, especially in channels with delayed and dispersed signal paths.
Innovation Solution
A method and apparatus for symbol synchronization that involves correlating the received digital signal with a delayed version, removing the effect of the strongest path to isolate the contribution of the fastest path, and using the resulting correlation to determine the symbol synchronization timing, thereby reducing errors and avoiding ISI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional correlation-based symbol timing estimation is used, then the algorithm is simple and memory resources are saved, but symbol timing accuracy deteriorates in multipath environments due to strongest path dominance
Solution Approach 1:
The patent segments the multipath channel into distinct path components (fastest path and strongest path) and processes them separately through iterative correlation and subtraction operations. This allows accurate identification of the fastest path timing while maintaining manageable algorithmic complexity through structured processing steps.
Solution Approach 2:
The patent extracts and removes the strongest path component from the correlation result to isolate the fastest path contribution. By taking out the dominant strongest path effect through subtraction, the algorithm can accurately detect the fastest path timing without being masked by the stronger signal.
2Measurement precision
If conventional correlation-based symbol timing estimation is used, then device complexity is low, but symbol timing accuracy deteriorates due to strongest path masking the fastest path
Solution Approach 1:
The patent converts the harmful effect of the strongest path (which masks the fastest path) into a useful component by first detecting and subtracting it. The strongest path, originally causing harm through masking, becomes a removable artifact that when eliminated reveals the true fastest path timing, thereby improving both accuracy and reliability.
3Measurement precision
If double correlation method is used to detect fastest timing, then symbol timing accuracy improves, but memory resource requirements increase
Solution Approach 1:
The patent creates a simplified copy or model of the correlation process that operates iteratively on the same signal data. Instead of requiring separate full correlation operations, it uses sequential correlation and subtraction steps that reuse the same signal buffer, thereby maintaining accuracy while reducing memory requirements compared to traditional double correlation methods.
4Device complexity
If conventional timing estimation is used, then algorithm simplicity is maintained, but Inter-Symbol Interference occurs due to incorrect FFT placement
Solution Approach 1:
The patent performs preliminary detection and removal of the strongest path component before final timing determination. This preliminary action clears the masking effect that would otherwise lead to incorrect FFT placement and subsequent ISI, allowing the simple correlation-based approach to yield accurate results without generating harmful interference.
Data Source
AI summary
A method for symbol synchronization of received digital signal and a digital signal reception apparatus are provided. The method comprises steps of correlating the received digital signal with the received signal delayed by one symbol so as to obtain a first correlation value result as a combined effort of a strongest path and other paths; removing substantially effect of the strongest path from the first correlation result so as to obtain a second correlation result which exhibits contribution of a fastest path; searching a maximum correlation value and its position of the fastest path so as to determine symbol synchronization timing for initiating FFT processing. The digital signal reception apparatus is characterized by a symbol timing detecting unit for determining symbol synchronization timing of the fastest path through substantially removing the effect of a strongest path.