Relay Device Bypass Pathway for Bus Signal Reflections
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Solution Overview
Problem
In vehicle-mounted networks, increasing communication rates lead to signal reflections and delays due to conventional network configurations, and existing solutions like using a gateway ECU to connect divided buses increase communication time.
Innovation Solution
A relay device with a signal processing and forwarding pathway and a bypass connection pathway that processes and forwards signals between buses, directly connecting buses during arbitration and separating them during data transmission to reduce reflections and delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the communication rate is increased to 2 Mbps in the conventional network configuration, then the data transmission rate is improved, but data are not correctly transmitted due to signal reflection
Solution Approach 1:
The patent divides the bus network into multiple segments using relay devices. Each segment is electrically isolated from others, preventing signal reflections from propagating across the entire network. This segmentation allows high-speed communication (2 Mbps) within each segment while maintaining data integrity by limiting the electrical length of each bus segment to acceptable levels.
2Reliability
If the buses are divided to reduce network scale and communication rate, then signal reflection is reduced, but the number of ECUs that can perform communication at the same time is reduced
Solution Approach 1:
The relay device acts as an intermediary between divided bus segments. It receives signals from one segment, regenerates them, and forwards them to other segments. This intermediary function allows multiple ECUs across different segments to communicate simultaneously at high speeds while maintaining signal quality, as the relay device manages the segmentation transparently.
3Adaptability or versatility
If a gateway ECU is used to connect divided buses, then communication between ECUs on different buses is enabled, but the communication time is increased
Solution Approach 1:
The patent extracts the signal regeneration and forwarding function from the ECU layer and implements it at the physical layer through dedicated relay devices. This separation allows ECUs to communicate without the processing delays associated with gateway ECUs, as the relay devices operate transparently at the signal level, enabling direct high-speed communication between ECUs on different bus segments.
4Reliability
If the network scale is reduced by dividing buses, then signal reflection is suppressed, but the network complexity increases due to additional relay devices
Solution Approach 1:
The relay device is designed as a universal component that can interface with multiple bus segments and handle various signal types. Each relay device performs the same core functions (signal reception, regeneration, and forwarding), making them interchangeable and simplifying network configuration. This universality reduces overall network complexity despite the presence of multiple relay devices, as they all follow the same operational pattern.
Data Source
AI summary
Provided are a relay device and the like with which it is possible to suppress bus signal reflections and suppress signal delays. A relay device 100A includes a signal processing and forwarding pathway P1 and a bypass connection pathway P2. The signal processing and forwarding pathway P1 processes a signal received from one bus CAN1 of a plurality of buses, and forwards the processed signal to another bus CAN2. The bypass connection pathway P2 connects the one bus CAN1 to the other bus CAN2, bypassing the signal processing and forwarding pathway P1.