Distributed NAV Management for V2X RAT Coexistence

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Solution Overview

Problem

Current Intelligent Transport Systems (ITS) and Vehicle-to-Everything (V2X) technologies lack mechanisms for coexistence and interoperability between different radio access technologies (RATs) such as IEEE-based DSRC and 3GPP C-V2X, leading to inefficient sharing of radio resources and channel utilization in the 5.9 GHz band.

Innovation Solution

Implementing a distributed timing management system using Network Allocation Vector (NAV) mechanisms to coordinate the operation of multiple V2X RATs, allowing for deterministic time slots and efficient coexistence by setting NAV indicators to prevent interference between different RATs, and dynamically allocating channels based on locally observed penetration levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple V2X RATs operate in the same communication channel without coordination, then each RAT can independently utilize the channel, but interference between RATs increases and channel utilization becomes inefficient

Engineering Contradiction:

Improvechannel utilizationVSAvoidinterference between RATs

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The communication channel is segmented into dedicated time slots for different V2X RATs. The system divides the channel access time into separate intervals, with each RAT assigned specific time windows for transmission. This temporal segmentation eliminates interference while maintaining high channel utilization through coordinated access.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system implements periodic time-division multiplexing where different RATs take turns accessing the channel in repeating cycles. Each RAT is granted periodic access rights during its assigned time slots, creating a rhythmic pattern of channel usage that ensures fair resource distribution and prevents continuous interference.

Inventive Principle:

Principle #19Periodic action

2Object-affected harmful factors

If a centralized coordination mechanism is implemented to manage RAT coexistence, then interference is reduced, but system complexity and deployment difficulty increase

Engineering Contradiction:

Improveinterference between RATsVSAvoidcoordination system complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Each V2X RAT is equipped with autonomous capabilities to detect the presence of other RATs, determine appropriate time slots, and self-organize channel access without external coordination. The system uses distributed algorithms where each node independently makes decisions based on local observations, eliminating the need for centralized control infrastructure.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system implements feedback mechanisms where each RAT monitors channel usage, detects transmissions from other RATs, and adjusts its own transmission timing accordingly. This closed-loop control enables dynamic adaptation to changing channel conditions and RAT penetration levels, maintaining efficient coexistence through continuous environmental awareness.

Inventive Principle:

Principle #23Feedback

3Object-affected harmful factors

If static time-division multiplexing is used to allocate channels to different RATs, then interference is minimized, but adaptability to changing traffic conditions and RAT penetration levels is reduced

Engineering Contradiction:

Improveinterference between RATsVSAvoidadaptability to traffic conditions

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The time-division multiplexing configuration is made dynamic and adaptable to changing conditions. The system continuously monitors traffic load, RAT penetration levels, and channel utilization metrics, then dynamically adjusts time slot allocations, durations, and patterns. This enables the network to optimize performance based on real-time environmental factors while maintaining interference-free operation.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11792616B2Distributed network allocation vector management for enabling vehicle-to-everything radio access technology coexistence

Publication Date: 2023.10.17 INTEL CORP

AI summary

Disclosed embodiments include technologies for managing co-existence among multiple Vehicle-to-Everything (V2X) Radio Access Technologies (RATs) through the setting of a Network Allocation Vector (NAV). MAC layer frame headers contain a duration field that specifies a transmission interval during which a shared channel will be occupied by a particular V2X RAT. The NAV indicates the time period intended to be held for the particular V2X RAT, and acts as an indication for how long stations implementing different V2X RATs must abstain from accessing the shared medium. Stations listen on the shared medium to obtain the MAC layer frame, read the duration field, and set their NAV indicators accordingly. Other embodiments are described and/or claimed.