Extended CAN Bus Frames for Real-Time IPv6 Data Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current CAN bus technologies, such as CAN 2.0 and CAN FD, are inadequate for supporting IPv6 communication due to limitations in data packet size and increased susceptibility to errors, overhead, and latency issues, making them unsuitable for real-time applications and large data transmission.
Innovation Solution
The development of an extended CAN protocol (CAN EL) that increases the data field length in transmission frames to up to 4096 bytes, allowing for higher data rates and flexibility, while maintaining low hardware costs and real-time capabilities, by using a modified bit stuffing rule and prioritization of messages through identifier assignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If CAN 2.0 or CAN FD bus is used for data transmission, then hardware costs are kept low and real-time capabilities are maintained, but the maximum message size is limited to 8 or 64 bytes which is insufficient for IPv6 communication requirements
Solution Approach 1:
The patent changes the data field length parameter from the traditional 8 bytes (CAN 2.0) or 64 bytes (CAN FD) to a variable length that can accommodate up to at least 1280 bytes, enabling support for IPv6 MTU requirements while maintaining the CAN bus architecture
Solution Approach 2:
The patent introduces dynamic message length capability where the data field can be configured to different sizes depending on the communication requirements, allowing the system to adapt between small control messages and large IPv6 packets without requiring separate bus systems
2Adaptability or versatility
If ISO TP transport protocol is used to transmit IPv6 packets via CAN FD, then IPv6 communication is enabled, but segmentation is required which increases error susceptibility and overhead
Solution Approach 1:
The patent extracts the segmentation requirement by enabling direct transmission of large IPv6 packets in a single CAN EL frame, removing the need for ISO TP segmentation and thereby eliminating the associated error susceptibility and overhead
3Adaptability or versatility
If ISO TP transport protocol is used with stateful point-to-point connections, then data transmission is established, but latency times become very long which is unsuitable for real-time applications
Solution Approach 1:
The patent inverts the connection model by using stateless broadcast/multicast communication instead of stateful point-to-point connections, allowing multiple receivers to process IPv6 packets independently without waiting for acknowledgments, thereby dramatically reducing latency
4Quantity of substance
If Ethernet technology is used for IPv6 communication, then sufficient bandwidth and packet size support are achieved, but hardware costs increase significantly for the automotive sector
Solution Approach 1:
The patent makes the CAN bus system multi-functional by extending it to handle both traditional automotive control messages and large IPv6 packets, eliminating the need for separate Ethernet infrastructure and reducing hardware costs while maintaining IPv6 compatibility
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to an extension of the existing CAN FD data transmission protocol. The extension aims to enable the use of the IPv6 protocol for the CAN bus. To this end, the CAN FD protocol is further developed in an incompatible manner. One modification involves extending the data field (DF) which is positioned after an arbitration field (AF) in the transmission frame. Any number of bytes may be entered into the extended data field (DF) within a defined upper limit. Since the data field (DF) is transmitted at a higher bit rate than the arbitration field (AF), the data throughput is drastically increased.