Vehicle Network Collision Handling via IEEE 802.3 Feedback
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Solution Overview
Problem
Current vehicle communication systems face issues with contention resolution on shared media, leading to potential frame loss due to collisions, which can impair vehicle control functions and user experience.
Innovation Solution
A modified version of the IEEE 802.3 standard is implemented to handle physical layer and data link layer media access control in vehicle communication subsystems, using a shared medium in half-duplex mode, with modifications to the Collision Avoidance Reconciliation Sublayer and backoff mechanisms to prevent undetected frame loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If legacy receiver implementations ignore received data after collision signal is asserted, then collision handling is simplified, but frame loss occurs and vehicle control functions may be impaired
Solution Approach 1:
The patent implements a feedback mechanism where the receiver detects collision signals and sends feedback information to the transmitter. This feedback allows the transmitter to determine whether the collision affected its transmission, enabling it to retry only when necessary. The feedback loop prevents frame loss by ensuring the transmitter knows when to retransmit, while avoiding unnecessary retries that would increase complexity.
Solution Approach 2:
The patent introduces an intermediary collision detection mechanism that mediates between the transmitter and receiver during collision events. The intermediary system detects the collision signal and manages the retry process, acting as a mediator that coordinates between multiple data terminal equipment. This intermediary approach resolves the contradiction by providing structured collision handling that maintains reliability without excessive complexity.
2Reliability
If components wait a random back-off period after collision, then collision resolution is achieved, but transmission delay increases and productivity decreases
Solution Approach 1:
The patent implements dynamic back-off behavior where the wait period is not always random but adapts based on collision detection results. When no collision is detected, transmission proceeds immediately. When collision is detected, a random back-off is applied. This dynamic approach optimizes transmission efficiency by avoiding unnecessary delays while maintaining collision resolution effectiveness when needed.
Solution Approach 2:
The patent changes the parameter of back-off time from a fixed random value to a conditional value that depends on collision detection status. The back-off parameter is adjusted based on whether a collision actually occurred, transforming it from a conservative always-wait approach to a selective wait approach. This parameter change improves productivity by reducing unnecessary delays while maintaining reliability through targeted collision handling.
3Productivity
If multiple components transmit simultaneously on shared medium, then network utilization increases, but collisions occur and frame loss increases
Solution Approach 1:
The patent uses feedback from collision signal detection to manage simultaneous transmissions. When multiple components transmit simultaneously, the collision signal provides feedback that triggers coordinated retry behavior. This feedback mechanism allows the system to tolerate simultaneous transmissions (maintaining high network utilization) while recovering from collisions reliably (maintaining frame delivery reliability).
Solution Approach 2:
The patent converts the harmful collision signal into a beneficial retry trigger. Instead of treating collisions purely as errors to be avoided, the system uses the collision signal as useful information to coordinate retransmissions. This transforms the harmful effect of simultaneous transmissions into a beneficial mechanism for managing network contention, allowing high utilization while maintaining reliability through intelligent retry coordination.
Data Source
AI summary
Embodiments of the present disclosure are directed to vehicle communication systems, in particular, toward contention resolution on a shared medium in vehicle communication systems. The present disclosure can provide a modified version of the Institute of Electrical and Electronics Engineers (IEEE) 802.3 standard to handle physical layer (PHY), and data link layer's (DLL) media access control (MAC) of the wired communication links in the vehicle communication subsystem utilizing a shared medium and half-duplex mode. As a result, the modified MAC and PHY may provide fair access and deterministic latency for shared access to the medium of vehicle communication systems independent of the offered network load.