Sensing System Data Synchronization via Timestamp Adjustment
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Solution Overview
Problem
Existing vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) communication systems face challenges in synchronizing data without relying on external clocks, which can be costly in terms of processing and bandwidth.
Innovation Solution
A system that assigns receipt timestamps to messages and adjusts them by subtracting the timestamp difference between object perception and capture, along with estimated message transmission latency, to synchronize data from senders and receivers without external clock references.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external clock references are used to synchronize data between vehicles and infrastructure, then synchronization accuracy is improved, but processing cost and bandwidth consumption increase
Solution Approach 1:
The system uses each device's own local clock to generate timestamps for data packets, eliminating the need for external clock references. Devices independently timestamp their own data and use these self-generated timestamps for synchronization calculations, reducing processing overhead while maintaining synchronization accuracy.
Solution Approach 2:
The patent introduces message transmission latency as an intermediary parameter that mediates between different local clocks. By measuring and compensating for transmission latency, the system can synchronize data from different sources using their own local timestamps without requiring external clock synchronization infrastructure.
2Measurement precision
If external clock references are used to synchronize data between vehicles and infrastructure, then synchronization accuracy is improved, but bandwidth consumption increases
Solution Approach 1:
Devices independently generate and include their own timestamps in transmitted data packets, eliminating the need to transmit external clock reference signals. This self-timestamping approach reduces bandwidth consumption while maintaining the ability to synchronize data accurately through latency compensation.
Solution Approach 2:
The system performs preliminary timestamping of data at the source before transmission, rather than requiring post-reception synchronization using external clocks. This preliminary action embeds timing information directly in the data stream, reducing subsequent bandwidth requirements for synchronization protocols.
3Measurement precision
If timestamp adjustment and latency compensation are performed, then data synchronization is improved, but computational complexity increases
Solution Approach 1:
The system measures actual message transmission latency and uses this feedback to adjust timestamp interpretations. By continuously measuring and compensating for latency based on actual observations rather than theoretical calculations, the system achieves accurate synchronization with relatively simple computational operations.
Solution Approach 2:
The patent replaces complex mechanical clock synchronization mechanisms with software-based timestamp and latency compensation algorithms. This substitution uses simple arithmetic operations on timestamps rather than complex hardware synchronization protocols, reducing computational complexity while maintaining synchronization precision.
Data Source
AI summary
In a message receiver, a receipt timestamp is assigned according to a time of wirelessly receiving a message. Object data about an object is extracted from the message, including a timestamp adjustment for the object from a message sender. An estimated sender capture timestamp is assigned to the object by subtracting the timestamp adjustment and an estimated message transmission latency from the receipt timestamp; a receiver capture timestamp is assigned to receiver object data captured in the receiver. The sender object data and the receiver object data are combined according to the estimated sender capture timestamp and the receiver capture timestamp, thereby generating combined object data.