Single-DCI PDSCH Scheduling With Unified HARQ-ACK Codebook
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Solution Overview
Problem
The communication systems using higher frequency bands face increased downlink and uplink signaling overhead and transmission delays due to separate downlink control information for scheduling multiple physical downlink shared channels and hybrid automatic repeat request acknowledgments.
Innovation Solution
A method and apparatus for scheduling data channels and performing HARQ feedback, where multiple PDSCHs are scheduled using a single DCI, and HARQ-ACKs are transmitted through a single PUCCH resource in a unified HARQ-ACK codebook, with the codebook size determined by a specific value rather than the number of PDSCHs, reducing signaling overhead and transmission delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate DCI is used for scheduling each PDSCH, then scheduling flexibility is improved, but downlink signaling overhead increases
Solution Approach 1:
The patent combines multiple PDSCH scheduling functions into a single DCI message. The DCI includes a time domain resource assignment field that can indicate multiple SLIV pairs, allowing one DCI to schedule multiple PDSCHs with different time resources. This merging approach reduces downlink signaling overhead while maintaining scheduling flexibility through the multi-resource indication capability.
Solution Approach 2:
The DCI structure is designed with multi-functionality to handle both single and multiple PDSCH scheduling. The time domain resource assignment field can interpretively indicate either a single SLIV or multiple SLIV pairs based on the scheduled PDSCH count. This universal design allows the same DCI format to serve multiple scheduling scenarios without requiring separate specialized messages.
2Reliability
If multiple HARQ-ACKs are transmitted through different PUCCH resources, then feedback reliability is improved, but uplink signaling overhead and transmission delay increase
Solution Approach 1:
The patent merges multiple HARQ-ACK feedbacks into a single PUCCH transmission. The terminal determines a single PUCCH resource based on the last PDSCH's time domain resource assignment and transmits all HARQ-ACKs for multiple PDSCHs through this unified resource. This combining approach reduces uplink signaling overhead and transmission delay while maintaining feedback reliability through the consolidated transmission mechanism.
Solution Approach 2:
The patent establishes preliminary rules for determining the unified PUCCH resource based on the last PDSCH's time domain resource assignment before actual HARQ-ACK transmission. This preliminary determination of the PUCCH resource ensures that all HARQ-ACKs are prepared for consolidated transmission, reducing the need for multiple separate resource allocations and transmissions.
3Measurement precision
If HARQ-ACK codebook size is determined by the number of PDSCHs, then feedback accuracy is improved, but uplink transmission delay increases
Solution Approach 1:
The patent applies preliminary action by determining the HARQ-ACK codebook size based on a predetermined maximum number of PDSCHs that can be scheduled by one DCI, rather than waiting to count the actual number of scheduled PDSCHs. This advance determination of codebook size allows the terminal to prepare the feedback structure in advance, reducing processing delay while maintaining feedback accuracy through the predetermined sizing approach.
Data Source
AI summary
An operation method of a terminal in a communication system may comprise: receiving DCI from a base station; identifying a plurality of start and length indicator values (SLIVs) indicated by a time domain resource assignment field included in the DCI; determining a plurality of PDSCH resources based on the plurality of SLIVs; receiving a plurality of PDSCHs from the base station through the plurality of PDSCH resources; and transmitting, to the base station, a plurality of HARQ-ACKs in response to the plurality of PDSCHs.