Vehicle Network TDMA Scheduling for Reliable Mixed Traffic
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Solution Overview
Problem
Traditional vehicular networks have complex wiring harnesses and data transmission limitations, particularly with different categories of data traffic requiring differentiated quality of service (QoS) to ensure proper vehicle operation.
Innovation Solution
A vehicle onboard network using a time division multiple access (TDMA) system with a network allocation map to manage data transmission, allowing for higher data rates and reduced wiring complexity by synchronizing nodes and reserving time slots for different types of data traffic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional point-to-point wiring harnesses are used in vehicular networks, then data transmission can be established between vehicle computer and subsystems, but the wiring complexity becomes inherently complex and difficult to install and troubleshoot
Solution Approach 1:
The patent merges multiple point-to-point communication links into a single shared bus structure. Instead of having separate wiring harnesses for each subsystem connection, all nodes communicate over a common physical medium, dramatically reducing wiring complexity while maintaining communication reliability through protocol-based data routing and identification mechanisms.
Solution Approach 2:
The shared bus structure serves multiple functions simultaneously: it carries data between the vehicle computer and various subsystems, supports multiple communication protocols, and enables both sensor data collection and actuator control signaling through the same physical infrastructure, replacing numerous dedicated wiring harnesses with a universal communication backbone.
2Reliability
If different categories of data traffic are transmitted without differentiation, then the communication network is simple to manage, but quality of service criteria cannot be met for proper vehicle system operation
Solution Approach 1:
The patent segments data traffic into different categories or priorities, allowing critical vehicle control signals to be separated from non-critical multimedia traffic. This segmentation enables the network to apply different quality of service policies to different data types, ensuring that safety-critical communications receive guaranteed bandwidth and latency while less important traffic can utilize remaining capacity.
Solution Approach 2:
The system dynamically changes transmission parameters such as bandwidth allocation, transmission priority, and latency guarantees based on the type of data being transmitted. Critical control signals receive higher priority with guaranteed QoS parameters, while bulk multimedia traffic is transmitted with lower priority and relaxed timing requirements, allowing the network to adapt to different communication needs without increasing physical complexity.
3Speed
If sensor and control signaling data are transmitted frequently in small units, then low latency is achieved, but the communication overhead increases compared to bulk multimedia traffic
Solution Approach 1:
The patent implements periodic transmission cycles where sensor data and control signals are transmitted at regular, high-frequency intervals to ensure low latency. This periodic action guarantees that critical data is communicated frequently and promptly, while the structured cycle allows the system to batch less time-critical multimedia traffic, thereby managing the trade-off between transmission speed and overhead through rhythmic, predictable communication patterns.
Data Source
AI summary
A method of communication in a vehicle network is provided. An example method includes transmitting a network allocation map in a TDMA cycle, indicating reservation of time slots in the TDMA cycle. The method further includes transmitting a synchronization signal in the TDMA cycle, to synchronize the timing of nodes in the vehicle network. Each of the reserved time slots is identified by at least a network ID of a transmitting node in the vehicle network, and a slot type comprising one of a low latency traffic slot, and a bulk traffic slot. Further, the low latency traffic slots are repeated in the TDMA cycle at least as frequently as a guaranteed QoS latency parameter. Further, the bulk traffic slots are at least as long as a guaranteed QoS throughput parameter.