Fault-Tolerant Ring Network Using Bi-Directional Links
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Solution Overview
Problem
Current automotive networking technologies like CAN and MOST lack fault tolerance and high bandwidth required for X-by-wire applications, leading to increased costs due to redundant cabling in FlexRay solutions.
Innovation Solution
A fault-tolerant data communication system using single-channel bi-directional point-to-point links in a ring or daisy chain topology, with digital phase locked loops for clock recovery, allowing nodes to operate synchronously and reconfigure in case of failures without duplicate cabling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant cabling is used to provide fault tolerance (FlexRay), then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges bidirectional communication capabilities into a single cabling infrastructure, allowing data to flow in both directions through the same physical medium. This eliminates the need for separate redundant cables while maintaining fault tolerance through protocol-level mechanisms that can redirect traffic dynamically.
Solution Approach 2:
The system dynamically reconfigures communication paths in response to detected failures. When a node or link fails, the protocol automatically redirects data flow through alternative paths in the ring topology, providing adaptive fault tolerance without requiring static redundant cabling for every possible failure scenario.
2Device complexity
If single-channel bi-directional links are used, then device complexity is reduced, but reliability may worsen due to potential single point of failure
Solution Approach 1:
The network is segmented into a ring topology where each node connects to two neighbors, creating multiple independent paths between any two nodes. This segmentation allows the system to isolate failures to specific segments while maintaining communication through other segments of the ring.
Solution Approach 2:
The protocol acts as an intermediary that manages the single bi-directional links, implementing intelligent routing and error handling. When failures occur, the protocol mediates the redirection of traffic through intermediate nodes, effectively creating virtual redundant paths without physical redundant cabling.
3Productivity
If synchronous operation with digital phase locked loops is implemented, then productivity and determinism are improved, but device complexity increases
Solution Approach 1:
Each node in the network autonomously synchronizes its clock using a digital phase-locked loop that locks onto the bit timing of received frames from neighboring nodes. This self-service approach eliminates the need for a centralized clock master, distributing the synchronization function across all nodes and reducing overall system complexity.
Solution Approach 2:
The digital phase-locked loop implements feedback by continuously comparing the phase of the recovered clock with the incoming data stream and adjusting its output accordingly. This automatic feedback mechanism ensures precise synchronous operation without requiring complex external synchronization infrastructure.
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
The system provides deterministic and fault-tolerant communication with reduced costs, supporting existing and new automotive applications with lower jitter, suitable for real-time streaming applications like audio and video, while maintaining high reliability and efficiency.
Implementation Method 1
An improved data communication system in accordance with the present invention preferably uses single-channel bi-directional point-to-point links between nodes to send frames of data. When implemented with a digital phase locked loop (DPLL) for clock recovery, all nodes can operate synchronously to each other
Data Source
AI summary
A data communication system and an associated network node implementation is disclosed that, in certain embodiments, uses single-channel bi-directional communication links between nodes to send frames of data. The network nodes can be connected together in a ring or daisy chain topology with data frames sent in alternating directions through the bi-directional links. Such networks initially configured in a physical ring topology can tolerate single point failures by automatically switching to a logical daisy chain topology.