HARQ Process Control in NTN Wireless Devices
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Solution Overview
Problem
In wireless communication systems, especially those involving Non-terrestrial networks (NTN), the large Round Trip Time (RTT) between the user equipment and the network side equipment limits the number of Hybrid Automatic Repeat Request (HARQ) processes that can be effectively managed, leading to reduced system performance and reliability.
Innovation Solution
The proposed solution involves enabling or disabling HARQ processes in units of Timing Advance Groups (TAGs) based on information related to the TAG, such as Timing Advance Commands (TAC), allowing for more reasonable management of HARQ processes across different cells and networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ processes are enabled in all cells, then system reliability is improved, but system effectiveness deteriorates when RTT is large
Solution Approach 1:
The patent segments the cells into different Timing Advance Groups (TAGs) based on their RTT characteristics. Each TAG can independently control HARQ processes, allowing cells with small RTT to enable HARQ for reliability while cells with large RTT disable HARQ to maintain effectiveness. This segmentation resolves the contradiction by applying different HARQ configurations to different cell groups.
Solution Approach 2:
The patent implements local quality control by allowing each TAG to have its own HARQ configuration based on local RTT conditions. Instead of a uniform system-wide HARQ setting, each TAG independently determines whether to enable or disable HARQ processes based on its specific timing characteristics, optimizing both reliability and effectiveness locally.
2Reliability
If the number of HARQ processes is increased, then retransmission reliability is improved, but latency increases
Solution Approach 1:
The patent introduces dynamic control of HARQ processes based on RTT conditions. When RTT is small, HARQ processes are enabled to improve reliability through retransmission. When RTT is large, HARQ processes are disabled to reduce latency. This dynamic adjustment resolves the contradiction by adapting HARQ configuration to real-time timing conditions.
3Reliability
If HARQ is enabled for all cells, then decoding reliability is improved, but system performance deteriorates due to increased processing overhead
Solution Approach 1:
The patent segments cells into TAGs and applies HARQ only to specific segments (TAGs with small RTT) rather than all cells. This selective segmentation maintains decoding reliability for cells that benefit from HARQ while avoiding the processing overhead penalty for cells where HARQ would be detrimental to system performance.
Data Source
AI summary
The present application relates to an electronic device, a wireless communication method, and a computer-readable storage medium. The electronic device according to the present application comprises a processing circuit which is configured to: receive information related to a timing advanced group (TAG) from a network side device serving for the electronic device; and start or end an HARQ process between the electronic device and all cells in the TAG according to the information related to the TAG. By using the electronic device, the wireless communication method, and the computer-readable storage medium according to the present application, the HARQ process can be reasonably started/ended in a unit of the TAG.