HARQ Feedback Resource Selection for V2X Link Adaptation
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Solution Overview
Problem
Current V2X communication systems face challenges in efficiently managing hybrid automatic repeat request (HARQ) feedback, particularly in selecting appropriate acknowledgement/negative acknowledgement (A/N) resources based on channel conditions and geographical locations, which affects link adaptation and beamforming in vehicular communications.
Innovation Solution
The method involves selecting A/N resources from a set based on channel condition indicators such as CQI, distance, RSRP, and RSRQ, and geographical location, with pre-configured mapping relationships and zone partitioning, allowing for adaptive link adaptation and beamforming by transmitting HARQ feedback using the selected resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If common A/N resources are shared among all UEs, then resource allocation efficiency is improved, but feedback reliability deteriorates due to resource conflicts and interference
Solution Approach 1:
The patent segments the cell service area into cell center region and cell edge region, with different A/N resource allocation strategies for each segment. Cell center UEs use common A/N resources for efficient sharing, while cell edge UEs use dedicated A/N resources to avoid interference and ensure reliable feedback transmission.
Solution Approach 2:
The patent applies different resource allocation quality to different spatial locations: common resources are used in the cell center region where interference is manageable, while dedicated resources are allocated to cell edge regions where higher reliability is needed due to weaker signal conditions and potential interference from other cells.
2Reliability
If dedicated A/N resources are allocated to each UE, then feedback reliability is improved, but resource utilization efficiency deteriorates due to resource waste
Solution Approach 1:
The patent segments the cell service area into cell center region and cell edge region, with different A/N resource allocation strategies for each segment. Cell center UEs use common A/N resources for efficient sharing, while cell edge UEs use dedicated A/N resources to avoid interference and ensure reliable feedback transmission.
Solution Approach 2:
The patent dynamically selects between common and dedicated A/N resources based on the UE's geographical location and channel conditions. This dynamic allocation allows the system to optimize the trade-off between resource efficiency and feedback reliability for each UE individually.
3Reliability
If A/N resources are selected based on detailed channel conditions, then communication reliability is improved, but system complexity increases due to measurement and selection overhead
Solution Approach 1:
The patent uses channel condition parameters (CQI, RSRP, RSRQ, path loss) to select A/N resources, changing the resource allocation decision based on measured channel parameters. This allows reliable communication adaptation without requiring complex multi-dimensional analysis.
Solution Approach 2:
The patent simplifies the selection process by segmenting the service area into regions and mapping channel conditions to specific A/N resources or regions. This segmentation approach reduces the complexity of real-time decision-making while maintaining reliability.
4Reliability
If beamforming is applied to all zones, then communication performance is improved, but energy consumption increases due to continuous beam adjustment
Solution Approach 1:
The patent applies beamforming periodically or selectively based on channel conditions and UE location rather than continuously. Beamforming is activated when needed for cell edge UEs or in specific zones, allowing the system to maintain performance while reducing unnecessary energy consumption during stable conditions.
Data Source
AI summary
A method of hybrid automatic repeat request (HARQ) feedback can include receiving data transmitted from a transmission (Tx) user equipment (UE) or a base station (BS) over a channel at a reception (Rx) UE, selecting an acknowledgement/negative acknowledgement (A/N) resource from a set of A/N resources for a HARQ feedback of the data based on a channel condition of the channel or a geographical location of the Rx UE, and transmitting the HARQ feedback with the selected A/N resource.