Emergency Frame Transmission in WAVE Vehicle Systems
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Solution Overview
Problem
In WAVE-based vehicle communication systems, emergency frames face significant transmission delays due to contention-based EDCA schemes and channel interval constraints, even when prioritized, leading to potential safety issues in real-time communication scenarios.
Innovation Solution
An apparatus and method that utilize a channel router, emergency processor, and non-priority scheduler to identify and prioritize emergency frames for immediate transmission over generic frames, allowing emergency frames to be sent regardless of current channel intervals, thereby reducing transmission delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EDCA contention-based scheme is used for channel access, then channel access priority according to user priority is provided, but transmission delay occurs for emergency frames even when allocated to high priority queue
Solution Approach 1:
The patent segments the transmission queue into two distinct parts: a high priority queue for emergency frames and a normal priority queue for generic frames. This segmentation allows emergency frames to be handled separately from regular traffic, enabling immediate transmission when the channel is idle without being blocked by other frames in the same queue, thus resolving the contradiction between maintaining EDCA priority structure and eliminating emergency frame delays.
Solution Approach 2:
The patent implements preliminary action by continuously monitoring the channel status and maintaining emergency frames in a ready-to-transmit state in the high priority queue. When the channel becomes idle, emergency frames are immediately transmitted without waiting for contention resolution, thereby preempting the normal EDCA process and eliminating transmission delays for time-critical communications.
2Device complexity
If transmission is restricted to corresponding channel interval, then channel resource management is maintained, but transmission delay occurs until capable channel interval arrives
Solution Approach 1:
The patent introduces dynamic behavior to the transmission system by allowing emergency frames to bypass the static channel interval restriction. While normal frames must wait for their designated channel intervals (CCH or SCH), emergency frames can be transmitted immediately on any available channel, creating a dynamic exception to the rigid interval structure. This resolves the contradiction by maintaining interval management for regular traffic while providing flexible immediate access for emergencies.
3Adaptability or versatility
If multiple channels are operated with CCH and SCH intervals, then multi-channel functionality is achieved, but emergency frame transmission is delayed until appropriate interval arrives
Solution Approach 1:
The patent applies universality by enabling the high priority queue to serve multiple functions: it handles emergency frames that can be transmitted on any channel interval (CCH or SCH), while also maintaining compatibility with the existing multi-channel structure. This allows the system to utilize both CCH and SCH resources for emergency transmissions, making the emergency transmission mechanism universally applicable across different channel types and eliminating delays associated with waiting for specific interval types.
Data Source
AI summary
In a vehicle communication system, a frame transmitting apparatus gives a transmission opportunity to an emergency frame received from an upper layer without EDCA (Enhanced Distributed Channel Access), and gives a transmission opportunity to a generic frame received from an upper layer through EDCA.