HARQ Process Sharing for Configured Grants in NR-U
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Solution Overview
Problem
In NR-U systems, the inefficient utilization of HARQ processes due to dynamic LBT success rates and potential HARQ process shortages lead to resource waste and increased latency, especially for high-priority data transmissions.
Innovation Solution
Implementing a mechanism where multiple configured grant resources share a common pool of HARQ processes, allowing terminal devices to select an appropriate process based on priority and availability, ensuring efficient utilization and low latency for high-priority data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple configured grant resources are allocated to terminal devices, then resource utilization ratio increases, but HARQ process shortage occurs leading to increased latency
Solution Approach 1:
Multiple configured grant resources share a common pool of HARQ processes instead of each resource having dedicated HARQ processes. The network device configures multiple configured grant resources to share the same HARQ process pool, allowing dynamic allocation and reducing HARQ process shortage while maintaining high resource utilization.
Solution Approach 2:
The system dynamically selects HARQ processes from the shared pool based on LBT success rates and transmission priorities. When LBT fails, the system can dynamically allocate available HARQ processes to different configured grant resources, adapting to changing channel conditions and preventing latency increases.
2Reliability
If dedicated HARQ processes are assigned to each configured grant resource, then transmission reliability improves, but resource waste increases due to low LBT success rates
Solution Approach 1:
A single HARQ process pool serves multiple configured grant resources, making the HARQ processes universal and multi-functional. Each HARQ process can be allocated to any configured grant resource that needs it, eliminating the waste of dedicated HARQ processes while maintaining transmission reliability through dynamic allocation.
Solution Approach 2:
The system changes the allocation parameters of HARQ processes dynamically based on LBT success rates and transmission priorities. Instead of fixed dedicated allocation, the parameters (which HARQ process is allocated to which resource) are adjusted in real-time, reducing resource waste while preserving reliability.
3Productivity
If HARQ processes are shared across multiple configured grants, then throughput increases, but process selection complexity increases for terminal devices
Solution Approach 1:
The terminal device autonomously selects HARQ processes from the shared pool based on pre-configured rules and current channel conditions. The device performs self-service in selecting appropriate HARQ processes without complex network coordination, maintaining high throughput while managing selection complexity through local decision-making.
Solution Approach 2:
The system uses feedback mechanisms where the network device monitors HARQ process usage and throughput performance, then adjusts the shared pool configuration and allocation rules accordingly. This feedback loop optimizes the balance between throughput and selection complexity by adapting to actual system performance.
Data Source
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AI summary
Embodiments of the present disclosure relate to mechanism for sharing HARQ processes by multiple configured grant resources. According to embodiments of the present disclosure, multiple configured grant resources share a common pool of HARQ processes. The network device transmits information concerning the multiple configured grants resources and the common pool HARQ process to the terminal device. Further, for one of the multiple configured grant resources, the terminal device selects a HARQ process from the common pool of HARQ processes. In this way, the throughput has improved and the low latency for high priority data is ensured.