Multi-Packet Protocol Header Detection with Variable Guard Preambles
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Solution Overview
Problem
In frequency-shift keying (FSK) systems, particularly in multi-packet protocols like Bluetooth, detecting the synchronization header is challenging due to the variable and undefined duration of the guard preamble, leading to potential missed packets and inefficient recovery from false signal detects.
Innovation Solution
A communication device and method that set a synchronization header timeout threshold shorter than the combined duration of the preamble and header, allowing for automatic frequency correction and gain control, and triggering the timeout based on detecting the end of the preamble, enabling efficient detection of synchronization headers even with variable guard preambles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a timeout threshold is set to cover the maximum possible duration of guard preamble plus header, then no packets are missed, but false signal detects cause unnecessary delays and reduced productivity
Solution Approach 1:
The patent segments the detection process into two distinct phases: guard preamble detection and synchronization header detection. Each phase has its own optimized timeout threshold. The guard preamble timeout is set to accommodate variable guard preambles, while the synchronization header timeout is set to a fixed, shorter duration. This segmentation allows the system to maintain reliability for packet detection while improving productivity by using a shorter timeout for the critical header detection phase.
Solution Approach 2:
The patent performs preliminary detection of the guard preamble end before initiating the synchronization header detection timeout. By detecting the end of the guard preamble first (using a separate timeout mechanism), the system prepares the receiver in advance for header detection. This preliminary action allows the synchronization header timeout to start at the optimal moment, ensuring no packets are missed while using the minimum necessary timeout duration, thus improving productivity.
2Measurement precision
If the receiver waits for the entire guard preamble duration before detecting the header, then detection accuracy is improved, but time loss increases
Solution Approach 1:
The patent performs preliminary detection of the guard preamble end using a dedicated timeout mechanism before initiating the synchronization header detection. This preliminary action prepares the receiver in advance, allowing it to start header detection at the optimal moment with high accuracy. The guard preamble timeout ensures the receiver waits long enough to accurately identify when the guard preamble ends, while the subsequent header timeout is set to a fixed, shorter duration that minimizes detection time without sacrificing accuracy.
Solution Approach 2:
The patent implements dynamic timeout management where the timeout threshold is not fixed but adapts based on the detection phase. During guard preamble detection, the timeout accommodates variable durations. Once the guard preamble end is detected, the system dynamically switches to a fixed, shorter timeout for synchronization header detection. This dynamic approach allows the system to maintain high detection accuracy when needed while minimizing time loss during the critical header detection phase.
Data Source
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AI summary
Aspects of this disclosure relate to detecting a header of a packet. A receive signal path can provide a receive signal that includes packets and a guard preamble between successive packets of the packets. A receiver control circuit can trigger a timer that sets a time for detecting a header of a packet in response to detecting an end of a preamble of the packet.