Adaptive Receiver Strobe Offset Selection for Distorted Data Buses
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Solution Overview
Problem
Existing automotive communication protocols, such as CAN and FlexRay, are vulnerable to bit stream distortions due to harsh channel characteristics, especially in networks with active elements or asymmetric topologies, leading to unreliable data reception and frame invalidation by single bit errors, as they rely on fixed strobe offsets suited for homogeneous distortion channels.
Innovation Solution
A receiver that employs variable strobe offsets adapted for optimal data stream reception, using a transmitted checksum to identify correct bit values and select the appropriate strobe offset for sampling, thereby enhancing robustness against signal distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed strobe offset is used for sampling data bits, then the receiver operates with simple circuitry and consistent sampling timing, but the receiver becomes highly sensitive to signal distortions in channels with asymmetric topology or active elements
Solution Approach 1:
The patent implements dynamic strobe offset adjustment by continuously varying the strobe offset across multiple cycles and selecting the offset that produces correct bit values according to the checksum. This transforms the static sampling mechanism into a dynamic adaptive system that automatically compensates for channel distortions.
Solution Approach 2:
The patent employs feedback through the checksum verification mechanism. The receiver samples data bits with different strobe offsets, validates them using the transmitted checksum, and uses the validation result to identify and select the correct strobe offset for subsequent sampling, creating a closed-loop adaptive system.
2Reliability
If variable strobe offsets are used to adapt to channel distortions, then the receiver achieves better robustness against bit stream distortions, but the circuit complexity and processing overhead increase
Solution Approach 1:
The patent segments the sampling process into multiple discrete strobe offset variations, where each offset samples the data bits independently. This segmentation allows the system to evaluate different sampling points separately and select the optimal one based on checksum validation, making the complex process manageable and systematic.
Solution Approach 2:
The patent changes the sampling parameter (strobe offset) across multiple cycles to adapt to channel conditions. By systematically varying this parameter and evaluating results through checksum validation, the system identifies the optimal sampling point without requiring complex real-time adjustment mechanisms.
3Reliability
If multiple strobe offsets are tested to identify correct bit values, then the receiver can compensate for static and dynamic bit distortions, but the reception time and processing delay increase
Solution Approach 1:
The patent implements periodic variation of the strobe offset across multiple cycles, systematically testing different offset values in a repeating pattern. This periodic approach allows the receiver to efficiently search for the correct offset while maintaining a structured and predictable timing pattern, reducing unnecessary delays.
Solution Approach 2:
The patent performs preliminary strobe offset identification during the reception process itself, using the transmitted checksum as a validation criterion. This preliminary action occurs concurrently with data reception rather than as a separate calibration phase, minimizing additional time loss while ensuring accurate offset selection.
Data Source
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AI summary
Receiver for receiving a data stream via a data bus, which receiver samples the bits of the data stream in an over-sampling process, in which n bit strobe offsets are used and n data sets with i bits are sampled, - applies a decision criterion for identifying those data sets with correct bit values. This decision uses checksum CRC, - selects one of the identified data sets with correct bit values and -uses the bit strobe offset, which was used for receiving the selected data streams, for receiving the data stream. In this way the multiphase clock with optimal phase shifts is selected.