Range-Based Message Filtering in Serial Bus Nodes
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Solution Overview
Problem
Existing message filtering methods in communication networks, such as CAN, FlexRay, and LIN, face challenges in efficiently allowing necessary messages while blocking superfluous ones, often requiring significant computational resources and risking accidental rejection of desired messages due to insufficient hardware filter capabilities and the complexity of acceptance masks.
Innovation Solution
Implementing a filter method that uses pairs of identifiers to define ranges, where incoming messages are compared against these pairs to determine if they fall within specific bands, allowing or rejecting messages based on their numerical values, thereby simplifying the filtering process and reducing resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If acceptance masks are used to allow groups of identifiers through, then the number of messages allowed through increases, but the risk of accidentally rejecting desired messages increases and filter precision decreases
Solution Approach 1:
The patent segments the filtering function into multiple independent filter lists, each containing specific identifier pairs. Instead of using a single broad acceptance mask that risks including unwanted messages, the system divides filtering into multiple precise segments (lists) that can be independently configured and evaluated, thereby maintaining precision while achieving comprehensive message acceptance through the combination of segments.
Solution Approach 2:
The patent transitions from traditional single-dimension filtering (single acceptance mask) to multi-dimensional filtering by introducing multiple filter lists with identifier pairs. Each list represents a different dimension of filtering criteria, and messages are evaluated against multiple dimensions simultaneously. This dimensional expansion allows precise control over which messages pass through without risking accidental inclusion or exclusion.
2Measurement precision
If multiple filter lists are used to achieve precise filtering, then filter precision improves, but the complexity of the filtering process and hardware resources increase
Solution Approach 1:
The patent segments the filtering function into multiple independent filter lists, each containing specific identifier pairs. Instead of using a single broad acceptance mask that risks including unwanted messages, the system divides filtering into multiple precise segments (lists) that can be independently configured and evaluated, thereby maintaining precision while achieving comprehensive message acceptance through the combination of segments.
Solution Approach 2:
The patent uses identical hardware filter structures replicated multiple times for different filter lists. Each filter list uses the same basic filter circuitry and comparison logic, but with different stored identifier pairs. This copying approach allows precise multi-dimensional filtering without proportionally increasing hardware complexity, as the same functional blocks are reused across multiple lists.
3Device complexity
If hardware filter options are limited, then device complexity decreases, but the ability to filter a wide range of identifiers adequately decreases
Solution Approach 1:
The patent makes the hardware filter structure universal by designing it to handle multiple filter lists with different identifier pairs. The same filter circuitry can be configured to evaluate messages against any number of different criterion sets by loading appropriate identifier pairs into the filter lists. This multi-functionality allows limited hardware to adapt to diverse filtering requirements across different applications and message types.
Solution Approach 2:
The patent introduces dynamic configurability to the filter system, allowing the identifier pairs in each filter list to be programmatically set and modified. Rather than fixed hardware filter settings, the system can dynamically load different filter criteria into memory-based lists, enabling the same hardware to adapt to changing filtering requirements without physical reconfiguration. This dynamic aspect greatly enhances versatility while maintaining hardware simplicity.
Data Source
AI summary
A method and a filter system for filtering messages which are received, via a serial data bus of a communications network, in a communication module of a user connected to the data bus. To allow particularly simple and efficient filtering of incoming messages, even when there is a large number of filtering criteria, it is proposed that the filter system includes a list in which multiple identifier pairs are stored which define a range delimited in each case by a first identifier and a second identifier. The identifier for an incoming message is compared at least to selected identifier pairs from the list, and a query is made concerning whether the identifier for the incoming message is greater than, or greater than or equal to, the selected first identifier, and is less than, or less than or equal to, the selected second identifier. The incoming message is forwarded to the application or rejected, depending on the configuration bit specification, if the identifier for the incoming message is within the range delimited by the first identifier and the second identifier.