Locomotive Wireless Control Implicit Sequence Numbering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Locomotive remote control systems face limitations in wireless communication due to frequency, bandwidth, and baud rate constraints, which restrict the amount of information that can be transmitted, making it challenging to efficiently encode safety-critical message integrity and sequence numbering information.
Innovation Solution
The system implements implicit message sequence numbering by calculating a CRC that encodes the sequence number, eliminating the need for an explicit sequence number in each message, allowing for reduced payload transmission and validating messages based on expected sequence numbers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If explicit sequence numbering is included in each wireless message, then message sequence identification and stale message detection are ensured, but the amount of information that must be transmitted increases, exceeding available bandwidth and baud rate capacity
Solution Approach 1:
The sequence number information is extracted from the explicit message payload and embedded within the CRC field. By removing the separate sequence number field and encoding its information into the CRC bits, the message payload size is reduced while sequence identification capability is preserved through the modified CRC validation process
Solution Approach 2:
The sequence number and error checking functions are merged into a single CRC field. Instead of transmitting separate sequence number and CRC values, the invention combines both functions into one field where the CRC calculation incorporates the sequence number, achieving dual functionality with reduced transmission overhead
2Reliability
If CRC and sequence number are transmitted separately, then message integrity and sequence tracking are maintained, but the payload size exceeds available communication bandwidth
Solution Approach 1:
The error detection and sequence tracking functions are merged into a single CRC field. The CRC calculation is performed over the message data including the sequence number, allowing the receiver to validate both message integrity and sequence correctness through a single CRC check, thereby improving communication efficiency
Solution Approach 2:
The CRC field is given multi-functionality by using it for both traditional error detection and sequence number transmission. This universal use of the CRC field allows the system to maintain message integrity verification while simultaneously conveying sequence information, eliminating the need for separate dedicated fields
Data Source
Figure 1
AI summary
A method for providing wireless communications between a locomotive control unit (LCU) (14) on board a locomotive (16) and a portable operator control unit (OCU) (12) for use in controlling operation of the locomotive from an off-board location includes calculating a transmit bit error check value for a wireless message. The wireless message includes an explicit sequence number assigned to the message so that the explicit sequence number is implicitly encoded in the transmit bit error check value. The method also includes transmitting an encoded message between the OCU and the LCU with the transmit bit error check value and without the explicit sequence number effective to reduce a total amount information needed to be transmitted compared to a message including the explicit sequence number.