Start of Frame Delimiter Detection via Dual Correlation
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Solution Overview
Problem
In ultra low power wireless communications, the short length of the start of frame delimiter (SFD) leads to difficulties in signal synchronization, resulting in packet loss and increased energy consumption due to retransmissions, especially in low signal-to-noise scenarios.
Innovation Solution
A method for detecting the start of frame delimiter that involves correlating a received stream of samples with a first sequence corresponding to the SFD pattern and a second sequence derived from the preamble, with additional evaluation criteria to ensure reliable detection, thereby reducing energy and data rate while avoiding false detections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the SFD length is kept short to minimize energy waste, then energy consumption is reduced, but the receiver's ability to identify the end of preamble deteriorates, leading to packet loss and retransmission energy increase
Solution Approach 1:
The detection process is divided into two independent correlation operations: one correlating the received signal with the SFD sequence, and another correlating with the preamble sequence. This segmentation allows each correlation to be evaluated separately with its own threshold, enabling reliable detection even with short SFD length while maintaining low energy consumption.
Solution Approach 2:
The patent introduces an intermediary evaluation mechanism by comparing correlation results against two different thresholds (one for SFD detection and one for preamble detection). This intermediary step acts as a mediator that resolves the conflict between short SFD length and reliable detection, allowing the system to distinguish true SFD signals from noise or false patterns.
2Reliability
If the SFD length is increased to improve detection reliability, then packet loss is reduced, but energy waste for non-data communication increases
Solution Approach 1:
The patent performs partial correlation operations by correlating only the necessary portions of the signal with the SFD and preamble sequences separately, rather than requiring the full extended SFD length. This partial action approach achieves sufficient detection reliability without the excessive energy cost of transmitting longer SFD sequences.
3Device complexity
If a single correlation threshold is used for SFD detection, then the detection process is simple, but false detections occur in low signal-to-noise scenarios
Solution Approach 1:
The detection process is segmented into two independent correlation operations with separate threshold evaluations. The first correlation checks against an SFD-specific threshold, and the second correlation checks against a preamble-specific threshold. This segmentation allows each threshold to be optimized for its specific purpose, improving detection accuracy in low signal-to-noise scenarios while maintaining manageable complexity.
Solution Approach 2:
The patent implements a feedback mechanism where the correlation results are evaluated against thresholds and the detection decision is refined based on both correlation outcomes. This feedback loop allows the system to adjust its detection behavior based on the actual signal characteristics, reducing false detections while maintaining a relatively simple overall process.
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
This approach enhances SFD detection performance by using an additional evaluation criterion, reducing energy and data rate consumption and minimizing false detections, which is particularly beneficial for ultra low power wireless communications without modifying the signal packet structure.
Implementation Method 1
a correlator is configured to correlate a received signal stream with a first known sequence corresponding to a start of frame delimiter (SFD) pattern present in a synchronization preamble of the received signal stream
Data Source
AI summary
The present disclosure is related to detecting a start frame delimiter. A received data packet is correlated with a known sequence, which provides a first correlation result. The received data packet is correlated with a predefined sequence, which yields at least a second correlation result. The data packet comprises at least a preamble portion and a header portion, whereby the preamble portion comprises the start frame delimiter. The predefined sequence is determined according to the preamble pattern. The method further comprises comparing the first correlation result with the second correlation result and comparing the first correlation result with a given threshold. The process of correlating will be continued until two criteria are met: the first correlation result is larger than the threshold and larger than the at least second correlation result. Only then it is decided that the start of frame delimiter pattern has been detected.