Autonomous Driving Sensor Bus Signaling for Low-Latency Emergencies
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Solution Overview
Problem
In autonomous driving systems, sensors face delays in communicating critical data to the central processor due to shared bus architectures, which can lead to latency issues and potential collisions.
Innovation Solution
Implementing a Time Division Multiplexed (TDM) bus with autonomous driving sensors communicating via a structural cable, using Power Line Communication (PLC) standards and differing power levels for normal and emergency messages, allowing emergency messages to be transmitted at higher power levels in non-assigned time slots to ensure timely and robust communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If sensors transmit data via a shared TDM bus, then device complexity is reduced and ease of operation is improved, but transmission latency increases and reliability deteriorates during emergency situations
Solution Approach 1:
The system changes the power level parameter of emergency messages to exceed normal operational messages. When an emergency is detected, the sensor transmits at a higher power level, which the central processor detects and prioritizes, effectively reducing latency for critical data without requiring a separate dedicated communication channel.
Solution Approach 2:
The system uses periodic time slots assigned to each sensor on the TDM bus, but allows emergency messages to interrupt the periodic schedule by transmitting at higher power levels during non-assigned time slots. This maintains the structured periodic framework while enabling urgent asynchronous communication.
2Ease of operation
If sensors use a shared TDM bus for communication, then ease of operation is improved, but transmission reliability worsens due to potential collisions and latency
Solution Approach 1:
The system applies different transmission qualities to different message types. Normal operational messages use standard power levels appropriate for routine communication, while emergency messages use elevated power levels to ensure reliable transmission through the shared bus, effectively creating quality differentiation within the same communication medium.
Solution Approach 2:
The system dynamically changes the power level parameter based on message urgency. By monitoring for emergency conditions and adjusting the transmission power parameter accordingly, the system maintains high reliability for critical messages while preserving the simplicity of the shared bus architecture for normal operations.
3Reliability
If emergency messages are transmitted at higher power levels, then reliability and timeliness are improved, but energy consumption increases
Solution Approach 1:
The system applies excessive action (higher power level) only partially and temporarily, specifically during emergency message transmission. Normal operational messages continue to use standard power levels, so the energy consumption increase is limited to brief emergency intervals rather than being continuous.
Solution Approach 2:
The transmission power level is dynamic rather than static. The sensor adjusts power levels based on the urgency of the message being transmitted, using high power only when necessary for emergency communication and returning to normal power levels for routine operations, thereby optimizing the balance between reliability and energy consumption.
Data Source
AI summary
A vehicular autonomous driving system includes a time division multiplexed (TDM) bus, an autonomous driving (AD) controller coupled to the TDM bus, and a plurality of AD sensors coupled to the TDM bus. The AD sensors are configured to collect AD data and transmit collected AD data to the AD controller on the TDM bus in an assigned time slot at a first power level. A first AD sensor of the plurality of AD sensors is configured to, based upon collected AD data, detect an AD emergency event. In response to the detection, the first AD sensor is configured to transmit an AD emergency message on the TDM bus in a non-assigned time slot and at a second power level that exceeds the first power level. The AD sensor may transmit the AD emergency message in a particular sub-slot of the non-assigned time slot.