DCI Format Scheduling for HARQ-ACK Feedback in LTE-NR Coexistence
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Solution Overview
Problem
In communication systems where LTE and NR coexist, the NR system cannot use the control resource sets (CORESET) and physical downlink control channel resources of the LTE system, leading to interference and reduced capacity of NR PDCCH, affecting system performance.
Innovation Solution
A method is introduced where downlink control information (DCI) is used to schedule PDSCHs across multiple carriers, allowing for the transmission of hybrid automatic repeat request acknowledgement (HARQ-ACK) codes in a way that avoids interference, by employing a second DCI format that schedules at least two PDSCHs, ensuring reliable HARQ-ACK feedback even when NR cannot use LTE's CORESET and PDCCH resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the NR system uses CORESET and PDCCH resources of the LTE system for dynamic spectrum sharing, then spectrum utilization is improved, but interference occurs and NR PDCCH capacity is reduced
Solution Approach 1:
The patent segments the HARQ-ACK feedback into multiple parts corresponding to different DCI formats and PDSCH scheduling scenarios. By dividing the feedback mechanism into distinct segments (first DCI format for single PDSCH, second DCI format for multiple PDSCHs), the system can selectively apply appropriate feedback strategies for each segment, thereby managing interference while maintaining spectrum sharing efficiency.
2Reliability
If the NR system avoids using LTE CORESET and PDCCH resources to prevent interference, then system reliability is improved, but NR PDCCH capacity is reduced
Solution Approach 1:
The patent implements a universal HARQ-ACK feedback mechanism that can handle multiple DCI formats and PDSCH scheduling scenarios through a single unified framework. The second DCI format, which can schedule multiple PDSCHs, serves multiple functions: it maintains reliability by providing clear feedback mechanisms while also enhancing NR PDCCH capacity by efficiently utilizing available resources across multiple carriers or bandwidth parts.
3Ease of operation
If a first DCI format scheduling one PDSCH is used, then scheduling simplicity is maintained, but scheduling efficiency is reduced
Solution Approach 1:
The patent introduces dynamic DCI formats that can adapt to different scheduling scenarios. The second DCI format dynamically schedules multiple PDSCHs based on system conditions, allowing the scheduling mechanism to transition from simple single-PDSCH scheduling to complex multi-PDSCH scheduling as needed. This dynamic approach maintains simplicity when appropriate while enabling high efficiency when required.
4Productivity
If a second DCI format scheduling at least two PDSCHs is used, then scheduling efficiency is improved, but feedback complexity increases
Solution Approach 1:
The patent implements a structured feedback mechanism where HARQ-ACK information is systematically organized to correspond with the multi-PDSCH scheduling. The feedback complexity is managed by establishing clear mapping relationships between the second DCI format, the scheduled PDSCHs, and the expected HARQ-ACK responses, allowing the system to handle complex scheduling while maintaining manageable feedback procedures.
Data Source
AI summary
Provided in the embodiments of the present application are a wireless communication method, a terminal device and a network device. The method includes: receiving at least one piece of downlink control information (DCI) sent by a network device; and determining or generating a target hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook, where the target HARQ-ACK codebook corresponds to the reception of a physical downlink shared channel (PDSCH) scheduled by the at least one DCI, the release of a semi-persistent scheduling (SPS) PDSCH indicated by the at least one DCI, or the dormancy of a secondary cell (SCell) indicated by the at least one DCI; and the at least one piece of DCI includes a first DCI format and/or a second DCI format, the first DCI format being used for scheduling one PDSCH, and the second DCI format being used for scheduling at least two PDSCHs.