Digital Radio Receiver Frame Sync Using Preamble-Length Matching
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Solution Overview
Problem
Existing digital radio receivers face challenges in accurately synchronizing with incoming radio signals due to noise and interference, leading to incorrect frame synchronization and decoding errors.
Innovation Solution
A method and digital radio receiver design that compares a selected portion of the incoming symbol sequence not only to a predetermined symbol sequence but also to symbol sequences formed by prepending different lengths of a preamble to the predetermined symbol sequence, using a difference metric to determine the minimum error, thereby improving synchronization accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple threshold comparison is used during frame synchronization, then the device complexity is reduced, but the reliability of synchronization decreases due to noise and interference
Solution Approach 1:
The patent applies preliminary action by comparing the received symbol sequence against multiple candidate sequences (including variations with different preamble lengths) before final synchronization decision. This preliminary comparison across multiple hypotheses allows the system to pre-identify the most likely correct frame alignment, reducing the risk of incorrect synchronization due to noise while maintaining a manageable decision process.
2Measurement precision
If the error threshold is set low to improve synchronization accuracy, then the reliability increases, but the noise tolerance decreases reducing the effective range
Solution Approach 1:
The patent applies dynamics by adaptively selecting from multiple candidate symbol sequences with different preamble lengths based on the actual received signal characteristics. Rather than using a fixed threshold or fixed candidate set, the system dynamically evaluates multiple hypotheses and selects the best match, allowing it to maintain high precision while being tolerant of varying noise conditions through flexible adaptation to signal quality.
3Object-affected harmful factors
If the error threshold is set high to improve noise tolerance, then the reliability increases, but the risk of incorrect frame synchronization increases leading to decoding errors
Solution Approach 1:
The patent applies segmentation by dividing the synchronization problem into multiple independent candidate comparisons rather than a single threshold decision. By segmenting the search space into multiple candidate sequences (with different preamble lengths), the system can evaluate each candidate separately and select the best match, reducing the risk that a high noise-tolerant threshold will incorrectly accept wrong frames while maintaining overall synchronization reliability.
4Measurement precision
If every possible symbol sequence is decoded during frame synchronization, then the measurement precision increases, but the use of energy increases significantly
Solution Approach 1:
The patent applies partial action by comparing the received symbol sequence against a limited set of candidate sequences (including variations with different preamble lengths) rather than exhaustively decoding every possible sequence. This partial comparison approach provides sufficient precision for frame synchronization while avoiding the excessive energy consumption that would result from complete enumeration and decoding of all possible sequences.
Data Source
AI summary
A method of operating a digital radio receiver is provided as follows: a) receiving a radio signal comprising a symbol sequence; b) selecting a portion of the symbol sequence; c) determining a first error between the selected portion of the symbol sequence and a first predetermined symbol sequence using a difference metric; d) determining a set of second errors between the selected portion of the symbol sequence and a respective set of second predetermined symbol sequences, each formed by prepending different length portions of a predetermined preamble symbol sequence to a beginning of the first predetermined symbol sequence; and e) determining a minimum error from the first error and the set of second errors. If the first error is not the minimum error, a different portion of the symbol sequence is selected. Otherwise, a following portion of the symbol sequence is decoded to produce a data payload.