Asymmetrical Time-Slot Bidirectional Ethernet for Automotive Weight Reduction
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Solution Overview
Problem
Existing Ethernet protocols face challenges in constrained environments such as automobiles, where weight, cost, and complexity issues arise due to separate transmission lines and symmetrical bandwidth allocation, leading to inefficiencies in data transmission and increased electromagnetic noise.
Innovation Solution
A networking system that uses a shared communication medium with asymmetrical bandwidth allocation and incorporates idle time slots to mitigate reflection distortion, eliminating the need for echo cancellation and allowing for increased signal strength, enabling efficient bidirectional data transmission between nodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If separate twisted pair transmission lines are used for upstream and downstream directions, then electromagnetic interference between directions is reduced, but weight and cost increase
Solution Approach 1:
The patent combines upstream and downstream transmission into a single shared transmission line, eliminating the need for separate twisted pairs for each direction. This merging approach reduces weight while managing electromagnetic interference through time-division multiplexing and impedance matching techniques.
Solution Approach 2:
The patent implements periodic time slots for upstream and downstream transmission, creating alternating transmission phases. This periodic action allows a single transmission line to handle bidirectional communication without continuous electromagnetic interference, as only one direction transmits at any given time.
2Ease of operation
If symmetrical bandwidth allocation is used for upstream and downstream directions, then fairness is achieved, but data transmission efficiency decreases when traffic patterns are asymmetric
Solution Approach 1:
The patent implements asymmetrical bandwidth allocation where upstream and downstream time slots can have different durations based on actual traffic requirements. This allows the system to optimize for dominant traffic directions (typically upstream in sensor networks) while maintaining fairness when needed, significantly improving overall data transmission efficiency.
3Weight of moving object
If a shared transmission line is used for bidirectional communication, then weight and cost are reduced, but reflection distortion increases
Solution Approach 1:
The patent converts the harmful reflection effect into a manageable phenomenon by using impedance matching at the end of the transmission line. This matching reduces reflections to acceptable levels, allowing the shared transmission line approach to succeed despite the inherent reflection problem.
Solution Approach 2:
The patent uses periodic time slots with idle periods between upstream and downstream transmission phases. These idle periods allow reflections to settle before the next transmission begins, converting the harmful reflection into a temporary disturbance that doesn't affect communication quality.
4Productivity
If echo cancellation is implemented to mitigate reflections, then bandwidth optimization is achieved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the echo cancellation function from the system by using passive impedance matching at the transmission line end instead of active echo cancellation circuitry. This removes complex processing requirements while achieving similar bandwidth optimization goals through simpler means.
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
This approach reduces weight and cost, optimizes bandwidth usage, and enhances signal strength in noisy environments by using a shared medium with asymmetrical bandwidth and idle time slots to manage reflections, improving data transmission efficiency in constrained settings.
Implementation Method 1
a first bidirectional interface that is configured to transmit electromagnetic signals to the transmission line and receive electromagnetic signals from the transmission line
Implementation Method 2
The first end is terminated with an impedance configured to reduce reflections from the first end by at least 80%, and the second end is terminated with an impedance configured to reduce reflections from the second end by at least 80%
Data Source
AI summary
Bidirectionally transmitting data between a first transceiver and a second transceiver over a transmission line includes communicating between the first transceiver and the second transceiver during a bidirectional communication phase within time slots. The time slots include: a plurality of upstream time slots in which the first transceiver transmits data to the second transceiver, a plurality of downstream time slots in which second transceiver transmits data to the first transceiver, wherein the downstream time slots are shorter than the upstream time slots, and a plurality of idle time slots separating adjacent upstream and downstream time slots.