TDM Bus Scheduling for Low-Latency Primary Data
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Solution Overview
Problem
Existing Ethernet data transmission protocols in vehicles exhibit high latency, making them unsuitable for applications requiring low-latency primary data such as road noise cancellation and drive-by-wire systems, while also needing to accommodate lower-priority secondary data like Ethernet control signals.
Innovation Solution
A communication system utilizing a time domain multiplexing (TDM) cycle beacon to segregate primary and secondary data transmission intervals, ensuring high-priority data is transmitted with minimal latency and allowing lower-priority data to be transmitted during idle periods, using a single network bus configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Ethernet data transmission protocols are used in vehicles, then the system can accommodate lower-priority secondary data like control signals, but the latency becomes too high for low-latency applications such as road noise cancellation and drive-by-wire systems
Solution Approach 1:
The patent segments the transmission medium into two distinct intervals: a primary data transmission interval for low-latency applications and a secondary data transmission interval for standard Ethernet traffic. This segmentation is achieved through TDM cycle beacons that delimit the primary data interval, allowing critical applications to transmit without interference from secondary data while maintaining compatibility with standard Ethernet protocols for non-critical traffic
Solution Approach 2:
The system implements periodic TDM cycle beacons that rhythmically structure the transmission medium into alternating primary and secondary data intervals. This periodic action creates predictable transmission windows for low-latency applications while systematically accommodating secondary Ethernet traffic, resolving the contradiction between latency requirements and protocol versatility
2Loss of time
If separate communication systems are used for primary and secondary data, then low-latency transmission can be achieved for high-priority data, but the system complexity and weight increase
Solution Approach 1:
The patent merges two separate communication requirements into a single communication system by implementing TDM-based intervals within one transmission medium. The primary data interval provides low-latency transmission for critical applications while the secondary data interval handles standard Ethernet traffic, eliminating the need for separate physical systems while maintaining performance requirements for both data types
Solution Approach 2:
The transmission medium is designed with multi-functionality to serve both low-latency primary data applications and standard Ethernet secondary data applications. Through the use of TDM cycle beacons and interval structuring, a single communication system universally accommodates diverse data requirements, reducing system complexity and weight compared to separate dedicated systems
Data Source
AI summary
A system for transmission of primary and secondary data, the system comprising: a bus; a parent node coupled to the bus; and a plurality of child nodes, each coupled to the bus, wherein: the parent node is configured to periodically transmit a time domain multiplexing (TDM) cycle beacon to the bus, wherein the TDM cycle beacon signals a start of a primary data transmission interval, and wherein the primary data transmission interval is a period reserved for transmission of primary data by the parent node and the plurality of child nodes; the parent node and each of the plurality of child nodes are operable to, responsive to the TDM cycle beacon, transmit primary data for a current TDM beacon period associated with the TDM cycle beacon to the bus during the primary data transmission interval; and the parent node and the plurality of child nodes are operable to transmit secondary data to the bus during a secondary data transmission interval between an end of the primary transmission interval and transmission by the parent node of a next TDM cycle beacon.