Illegal Signal Detection in Vehicle Networks Using Bus-State Timing
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Solution Overview
Problem
Existing systems struggle to accurately distinguish between legitimate and illegitimate signals in vehicle communication networks, particularly in the presence of signal delays due to competition or bus idle waiting, leading to potential misidentification of legitimate signals as illegitimate.
Innovation Solution
The system employs an ECU with a measuring unit and determination unit to analyze time intervals and signal lengths to differentiate between normal and illegal signals by considering competition and bus idle states, using thresholds and header information to make accurate determinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the system detects signals based on fixed cyclic timing, then it can identify normal periodic signals, but it misidentifies legitimate delayed signals as illegitimate due to competition or bus idle states
Solution Approach 1:
The system dynamically adjusts the expected signal arrival time window based on the detected bus state. When competition or idle states are detected, the system extends the acceptable time range for signal arrival, allowing legitimate delayed signals to pass validation. This resolves the contradiction by making the detection criteria adaptive rather than fixed, improving reliability without sacrificing measurement precision.
Solution Approach 2:
The system changes the time parameter thresholds for signal validation based on bus conditions. By detecting bus idle states and competition events, the system adjusts the acceptable time deviation range dynamically, allowing legitimate signals that arrive outside the normal cyclic window to be correctly identified as valid rather than illegitimate.
2Reliability
If the system strictly enforces cyclic signal timing, then it maintains network security, but it blocks legitimate signals that are delayed due to bus competition or idle states
Solution Approach 1:
The system implements dynamic timing validation that adapts to actual bus conditions. By monitoring bus idle states and competition events, the system flexibly adjusts the acceptable arrival time window, maintaining security through state-aware validation while preventing unnecessary blocking of legitimate delayed signals, thus improving transmission efficiency.
Solution Approach 2:
The system introduces bus state detection as an intermediary mechanism between signal transmission and validation. This intermediary provides context about bus conditions (idle states, competition events) that mediates the validation process, allowing the system to distinguish between malicious delays and legitimate delays caused by normal bus operations.
3Measurement precision
If the system monitors detailed bus states to distinguish signal types, then it improves detection accuracy, but it increases system complexity
Solution Approach 1:
The system segments the detection process into distinct functional modules: bus state detection unit, signal timing validation unit, and illegitimate signal determination unit. Each module handles a specific aspect of the detection process, making the overall complex system manageable and maintainable while achieving high detection accuracy through specialized processing in each segment.
Solution Approach 2:
The ECU is designed with multi-functional capabilities, serving both as a signal receiver and a bus state monitor. The same processing unit that validates signal timing also detects bus idle states and competition events, reducing the need for separate dedicated hardware components and thereby limiting the increase in device complexity.
Data Source
AI summary
An illegal signal detection apparatus for detecting input of an illegal signal to a communication network for which a signal is expected to be input at a predetermined cycle, the illegal signal detection apparatus including: a measuring unit for measuring, in time series, a time interval among a plurality of continuous signals input to the communication network; and a determination unit for judging, if a time interval between a first signal and a second signal that should be transmitted at the cycle is longer than the cycle, and a signal interval between the second signal and a signal that is input immediately before is equal to or smaller than a predetermined interval, that a competition has occurred when transmitting the second signal to determine that the second signal is an arbitrated normal signal.