PDSCH HARQ Scheduling Boundaries for NTN Timing Advance
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Solution Overview
Problem
The existing scheduling restrictions for Hybrid Automatic Repeat Request (HARQ) processes in Non-Terrestrial Networks (NTN) are not applicable due to the significant timing advance (TA) exceeding one slot, leading to unsynchronized HARQ process scheduling and potential errors.
Innovation Solution
A wireless communication method is introduced where the terminal device and network device agree on a first moment based on the transmission end of HARQ-ACK feedback, ensuring the terminal device does not expect to receive another PDSCH before this moment, enhancing scheduling restrictions in NTN systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing scheduling restriction for HARQ process is applied in NTN network, then the scheduling can be simple and fast, but the scheduling becomes inaccurate and causes errors due to large timing advance exceeding one slot
Solution Approach 1:
The patent changes the timing parameter from the existing HARQ timing restriction (based on microsecond-level TA) to a new timing advance value suitable for NTN (millisecond-level TA). This parameter change allows the scheduling restriction to accommodate the large propagation delays in satellite communications while maintaining the overall HARQ scheduling mechanism.
Solution Approach 2:
The patent introduces dynamic timing adjustment by setting the first moment based on the transmission end moment of HARQ-ACK feedback plus the timing advance value. This dynamic approach allows the scheduling restriction to adapt to varying propagation delays in NTN, making the system flexible rather than rigid.
2Productivity
If the terminal device expects to receive another PDSCH by scheduling the same HARQ process before the first moment, then the scheduling flexibility is improved, but scheduling errors occur due to unsynchronized HARQ process timing
Solution Approach 1:
The patent establishes the first moment in advance by calculating it as the transmission end moment of HARQ-ACK feedback plus the timing advance value. This preliminary definition of the timing boundary allows both terminal and network devices to synchronize their HARQ process expectations before actual data transmission occurs, preventing scheduling errors.
Solution Approach 2:
The patent uses HARQ-ACK feedback transmission as the reference point for determining the first moment. By anchoring the scheduling restriction to the feedback transmission timing, the system ensures that both parties have synchronized understanding of when the HARQ process becomes available for new scheduling, maintaining reliability while allowing flexibility.
Data Source
AI summary
Embodiments of the present invention provide a wireless communication method, a terminal device, and a network device, applicable to the technical field of communications. The embodiments of the present invention comprise: when a terminal device receives a first PDSCH transmitted by a network device by scheduling a first HARQ process, before a first moment, the terminal device does not expect to receive, again, a second PDSCH transmitted by the network device by scheduling the first HARQ process, wherein the first moment is determined according to a second moment, and the second moment is a transmission end moment when the terminal device sends, to the network device, first hybrid automatic repeat-request acknowledgement (HARQ-ACK) feedback information corresponding to the first PDSCH, or the second moment is a transmission end moment when the terminal device receives the first PDSCH.