V2V TDMA Time Base Synchronization
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Solution Overview
Problem
Current vehicle-to-vehicle (V2V) collision prevention systems face issues such as unnecessary complexity, non-deterministic message transmission, lack of priority systems, inadequate bandwidth allocation, exclusion of pedestrians and bicycles, and limited integration with personal mobile devices, which hinder widespread adoption and effectiveness.
Innovation Solution
A V2V system using a transceiver with TDMA protocols, eliminating MAC and IP addresses, employing vehicle position for identification, and implementing a hybrid method of time slot allocation to ensure deterministic and efficient message delivery, prioritizing safety messages, and incorporating proxying to include non-equipped vehicles, with a focus on high-priority message reliability and bandwidth management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CSMA/CA protocol is used for message transmission, then the system can handle non-real time applications, but deterministic delivery and reliability for safety-critical V2V communication cannot be achieved
Solution Approach 1:
The patent segments the communication protocol into distinct layers: a simplified MAC layer using TDMA for deterministic transmission, and higher layers handling application logic. This segmentation allows the critical transmission function to use simple, reliable TDMA while other functions can use more complex protocols if needed.
Solution Approach 2:
The patent extracts the deterministic transmission requirement from the complex CSMA/CA protocol and implements it separately using TDMA with pre-assigned time slots. This extraction isolates the reliability-critical function from the non-deterministic elements of CSMA/CA.
2Productivity
If TDMA time slots are uniformly allocated to all vehicles, then simple time slot assignment is achieved, but efficiency is reduced when some time slots remain unused while others are congested
Solution Approach 1:
The patent implements dynamic time slot allocation where vehicles can request additional time slots based on their communication needs and traffic conditions. The base station or coordinating vehicles adjust the allocation dynamically, allowing the system to adapt to changing conditions and improve overall efficiency.
Solution Approach 2:
The patent changes the parameter of time slot allocation from fixed and uniform to variable and demand-based. Vehicles with higher message rates or priority communications receive more time slots, while vehicles with lower needs receive fewer slots, optimizing the utilization of available bandwidth.
3Adaptability or versatility
If vehicle ID is assigned permanently, then vehicle identification is simplified, but the system cannot adapt to vehicles that are added or removed from the network
Solution Approach 1:
The patent implements self-service where vehicles autonomously select their own time slots and identifiers when joining the network, without requiring manual assignment or complex centralized management. This self-configuration capability allows the system to automatically adapt to new vehicles while maintaining simple identification mechanisms.
Data Source
AI summary
A device and vehicle for use in, and system for, a vehicle-to-vehicle (V2V) communication and safety system that uses TDMA communication architecture with a self-synchronized TDMA time base. The time base starts with a GPS and internal clock, then fine-tunes by averaging the time bases of all vehicles within radio range. In the described algorithms, all vehicles within a communication range rapidly converge on a common time base to high precision. The regularly broadcast safety messages themselves are used for time base synchronizing, eliminating the need for separate time stamps or transmissions. A range group of vehicles, first converges itself, then converges the group on a UTC time via GPS. Embodiments include use of vehicle distances in time computations. Applications anti-collision systems, optimized traffic flow and signal timing.