Sidelink Groupcast Link Adaptation via Distance-Based Feedback
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Solution Overview
Problem
Current LTE sidelink V2X communications primarily support broadcast scenarios, lacking feedback and link adaptation features, leading to low spectral efficiency in groupcast transmissions due to unawareness of intended receivers, and existing approaches either underutilize feedback or excessively consume radio resources.
Innovation Solution
Implementing ACK and NACK feedback-based link adaptation and power control for sidelink groupcast communications, where receivers select resources based on distance from the transmitter, allowing for optimized resource allocation and reduced interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If broadcast transmission is used for sidelink V2X communications, then coverage and reachability are improved, but spectral efficiency deteriorates due to lack of feedback and link adaptation
Solution Approach 1:
The patent segments the groupcast receivers into different distance-based groups (first group within first distance threshold, second group within second distance threshold). Each group uses different feedback mechanisms and resource allocation strategies, allowing the system to optimize spectral efficiency for each segment while maintaining broad coverage across all groups
Solution Approach 2:
The patent applies different quality characteristics to different spatial regions: receivers in the first distance group receive feedback and use link adaptation, while receivers in the second distance group use simplified feedback. This local differentiation optimizes spectral efficiency for nearby receivers while maintaining coverage for distant receivers
2Loss of energy
If feedback-based link adaptation is implemented for groupcast, then spectral efficiency is improved, but radio resource consumption increases
Solution Approach 1:
The patent divides feedback mechanisms into segments based on distance: full feedback (ACK/NACK) for the first distance group and reduced feedback for the second distance group. This segmentation allows spectral efficiency improvement where needed while controlling overall radio resource consumption
Solution Approach 2:
The patent changes the feedback parameter (from full ACK/NACK to reduced feedback) based on the distance parameter. This parameter adaptation allows the system to optimize spectral efficiency for close receivers while reducing radio resource consumption for distant receivers
Data Source
AI summary
Methods, computer programs and receiving wireless devices for operating a receiving wireless device associated with a group are provided, wherein the group includes the receiving wireless device and a transmitting wireless device. The method includes receiving a groupcast data packet from the transmitting wireless device of the group. The method further includes determining a distance of the receiving wireless device from the transmitting wireless device. The method further includes selecting a communication resource for one of an Acknowledgement, ACK, message or Negative Acknowledgement, NACK, message for the groupcast data packet, wherein the communication resource is selected based on the distance from the transmitting wireless device. The method further includes transmitting the one of the ACK message or NACK message for the groupcast data packet using the communication resource selected based on the distance from the transmitting wireless device.