V2X HARQ Feedback by Distance Range to Cut Retransmissions
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Solution Overview
Problem
In vehicle-to-everything (V2X) communication, existing HARQ technologies consume excessive time-frequency resources and reduce system capacity due to inaccurate distance calculations between vehicles, leading to inefficient data transmission and quality of service issues.
Innovation Solution
A communication method where a first terminal sends acknowledgment information based on a preset distance range and condition, using a first and second preset distance value, to ensure reliable data transmission and avoid unnecessary retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ technology is used in V2X multicast to ensure QoS, then data transmission reliability is improved, but time-frequency resources are consumed excessively and system capacity decreases
Solution Approach 1:
The patent applies local quality by differentiating QoS requirements based on distance ranges. Vehicles within the service distance range (assurance area) receive enhanced QoS with HARQ feedback, while vehicles outside this range do not trigger feedback mechanisms. This spatial differentiation ensures that resources are allocated locally where they are most needed, improving reliability for critical communications without unnecessarily consuming system capacity across all vehicles.
Solution Approach 2:
The patent segments the communication system into different distance ranges: an assurance area where distance ≤ service distance (requiring HARQ feedback) and a transition area where service distance < distance ≤ preset distance range. This segmentation allows the system to apply different feedback mechanisms to different spatial zones, optimizing the balance between reliability and resource utilization.
2Measurement precision
If location information is frequently exchanged between vehicles to determine distance, then distance measurement precision is improved, but time-frequency resources are consumed and system capacity decreases
Solution Approach 1:
The patent applies preliminary action by having the second terminal broadcast its location information periodically or at predetermined intervals rather than requiring continuous or on-demand exchanges. The first terminal caches this location information and uses it to determine distance, thereby preparing the necessary data in advance to avoid frequent communication overhead while maintaining sufficient measurement precision for QoS determination.
3Ease of operation
If reference signal received power is used to determine distance, then ease of operation is improved, but measurement precision deteriorates due to signal obstruction and calculation inaccuracies
Solution Approach 1:
The patent introduces a threshold value as an intermediary parameter between reference signal received power and actual distance. Instead of directly converting signal strength to distance (which is imprecise), the system uses the threshold to determine whether a vehicle is within the service distance range. This intermediary approach maintains ease of operation while improving measurement precision by avoiding direct reliance on inaccurate signal-based distance calculations.
Data Source
AI summary
Communications methods and apparatus for ensuring service data transmission reliability are described. The described methods and apparatus can relate to the field of communication technologies, and in particular, to vehicle to anything (V2X), intelligent driving, an intelligent connected vehicle, and similar communication technologies. For example, a method can include a first terminal receiving service data from a second terminal. If a distance value between the first terminal and the second terminal falls within a preset distance range, the first terminal sends, based on a preset condition, acknowledgment information indicating that the service data is received successfully or unsuccessfully to the second terminal. The preset distance range is determined based on a first preset distance value and a second preset distance value, and the second preset distance value is greater than the first preset distance value. The method can be applied to a communication process between terminals.