Shared-Media Packet Scheduling for Collision-Free Priority Transmission
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Solution Overview
Problem
Existing data transmission networks experience collisions and inefficiencies due to unmanaged prioritization of data packets, leading to bandwidth degradation, unpredictable latency, and jitter, particularly in time-sensitive applications like industrial automation and automotive networks.
Innovation Solution
A coordinated data packet transmission system utilizing a transmission controller that allocates non-overlapping times for data packet transmission through a prioritization scheme and a jamming mechanism to manage network bandwidth, employing Frame Start Markers and error correction to prevent collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nodes transmit data packets simultaneously on shared network media, then network utilization is improved, but data packet collisions occur causing transmission errors
Solution Approach 1:
The system performs preliminary actions by detecting the media state before transmission and establishing transmission schedules in advance. Nodes monitor the shared media to detect silence or ongoing transmissions, and the coordinator pre-allocates transmission opportunities to nodes based on priority levels, preventing collisions before they occur
Solution Approach 2:
A coordination packet mechanism acts as an intermediary between nodes and the shared media. The coordinator node generates coordination packets that contain transmission schedules and priority information, mediating access to the shared media to prevent collisions while maintaining high network utilization
2Loss of time
If high-priority packets are transmitted first, then latency for critical data is reduced, but lower-priority packets experience bandwidth monopolization
Solution Approach 1:
The system applies different transmission qualities to different packets based on their priority levels. High-priority packets are allocated preferential transmission opportunities with guaranteed access, while lower-priority packets receive transmission opportunities only when high-priority queues are empty, ensuring each packet type receives appropriate service quality
Solution Approach 2:
The coordinator node periodically generates coordination packets that re-evaluate and re-allocate transmission opportunities. This periodic action allows the system to dynamically adjust bandwidth allocation, preventing monopolization by ensuring that previously lower-priority packets can access the media in subsequent periods when conditions allow
3Reliability
If nodes monitor network traffic to detect silence, then collision detection is improved, but transmission latency increases
Solution Approach 1:
Nodes perform preliminary monitoring of the network medium to detect silence or ongoing transmissions before attempting to transmit. This advance detection allows nodes to prepare transmission buffers and synchronize timing, improving collision detection accuracy while minimizing actual transmission delay
Solution Approach 2:
The system implements feedback mechanisms where nodes continuously monitor the shared media for transmission signals from other nodes. This real-time feedback allows nodes to adjust their transmission timing dynamically, ensuring accurate collision detection while maintaining efficient network utilization through rapid response
Data Source
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AI summary
A media access control layer (MAC) or device for shared bus network system for collision-less data packet transmission, the media access control layer includes a transmission controller, priority queues, timestamper, and optional coordinator packet generator. The transmission controller is configured to decode a coordination packet received from the physical layer. The transmission controller is further configured to extract control information from the coordination packet. The transmission controller is further configured to generate a data packet transmission schedule and allocate non-overlapping time intervals to transmit the plurality of data packets with collision avoidance.