Terminal HARQ Feedback Configuration in NTN
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Solution Overview
Problem
In Non-Terrestrial Networks (NTN), the large distance between base stations and terminals results in increased propagation delay, and the movement of base stations in Low Earth orbit (LEO) or High Altitude Platform Station (HAPS) poses challenges for Hybrid Automatic Repeat Request (HARQ) feedback operations, with unclear conditions for enabling or disabling HARQ feedback.
Innovation Solution
A terminal is equipped with a reception unit to receive indications for activating Semi-persistent Scheduling (SPS)-PDSCH, a control unit to determine whether HARQ feedback is enabled or disabled, and a transmission unit to transmit HARQ feedback when enabled, allowing for the configuration of HARQ feedback in an NTN environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ feedback is enabled in NTN, then data transmission reliability is improved, but propagation delay increases and system complexity increases
Solution Approach 1:
The patent applies dynamics by making the HARQ feedback mechanism adjustable rather than fixed. The base station can dynamically configure whether HARQ feedback is enabled or disabled for SPS-PDSCH based on current network conditions, terminal capabilities, and propagation delay characteristics. This dynamic adaptation allows the system to optimize between reliability and latency requirements in different NTN scenarios.
Solution Approach 2:
The patent changes the parameter of HARQ feedback configuration from a fixed state to a configurable state. By introducing indication information that allows the base station to enable or disable HARQ feedback for SPS-PDSCH, the system can adjust this critical parameter to balance reliability improvements against propagation delay penalties and system complexity increases.
2Loss of time
If HARQ feedback is disabled in NTN, then propagation delay is reduced and system complexity is reduced, but data transmission reliability deteriorates
Solution Approach 1:
The system dynamically adjusts the HARQ feedback configuration based on actual network conditions. When propagation delay is critical or terminal processing capability is limited, the base station can disable HARQ feedback to reduce latency and complexity. When reliability is the priority and network conditions permit, the base station can enable HARQ feedback to improve data transmission reliability, thus optimizing the trade-off dynamically.
Solution Approach 2:
The patent enables flexible parameter configuration by allowing the base station to change the HARQ feedback enable/disable state based on SPS-PDSCH configuration and network conditions. This parameter change capability allows the system to adapt to different operational requirements, selecting the optimal balance between reliability and latency/complexity for each specific scenario.
3Adaptability or versatility
If HARQ feedback configuration is added for SPS-PDSCH, then system flexibility is improved, but device complexity increases
Solution Approach 1:
The control unit performs multiple functions: it determines whether to enable/disable HARQ feedback for SPS-PDSCH, generates indication information to communicate this configuration to the terminal, and manages the overall HARQ feedback mechanism. By consolidating these functions into a single control unit, the patent achieves system flexibility without proportionally increasing device complexity, as the control unit leverages existing processing capabilities for multiple purposes.
Data Source
AI summary
A terminal includes: a reception unit configured to receive, from a base station, an indication for activating SPS (Semi-persistent scheduling)-PDSCH (Physical Downlink Shared Channel) in an NTN (Non-Terrestrial Network) environment; a control unit configured to determine whether a HARQ (Hybrid automatic repeat request) feedback corresponding to the SPS-PDSCH is enabled or disabled; and a transmission unit configured to transmit the HARQ feedback to the base station in a case where the HARQ feedback is enabled.