Dynamic Hybrid HARQ Codebooks for Multi-User and Unicast PDSCH
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Solution Overview
Problem
The challenge in wireless communication systems is supporting dynamic HARQ codebooks for both multi-user PDSCH and unicast PDSCH communications, particularly in scenarios where data for multiple UEs is aggregated in a single packet, making it difficult for the base station to determine DAI values.
Innovation Solution
A user equipment determines a hybrid automatic repeat request (HARQ) codebook for both multi-user and unicast PDSCH communications and transmits separate ACK/NACK feedbacks using distinct or concatenated HARQ codebooks based on different reporting occasions, enabling efficient ACK/NACK feedback for both types of communications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data for multiple UEs is aggregated in a single multi-user PDSCH packet, then resource efficiency is improved, but it becomes difficult for the base station to determine DAI values for each UE
Solution Approach 1:
The patent segments the HARQ codebook into separate components for multi-user PDSCH and unicast PDSCH. Each segment maintains independent DAI (Downlink Assignment Index) tracking, allowing the base station to determine DAI values for each UE independently even when data is aggregated in a single multi-user packet. This segmentation resolves the contradiction by enabling individual UE identification within the aggregated transmission.
Solution Approach 2:
The patent introduces separate HARQ codebooks as intermediaries between the aggregated multi-user PDSCH transmission and the individual UE acknowledgments. These codebooks serve as mediators that track and manage DAI values for each UE separately, enabling the base station to resolve which UE received which data segment within the aggregated packet without requiring complex direct tracking.
2Measurement precision
If separate ACK/NACK feedbacks are transmitted for multi-user and unicast PDSCH, then feedback accuracy is improved, but resource overhead increases
Solution Approach 1:
The patent merges the transmission timing of ACK/NACK feedbacks for multi-user PDSCH and unicast PDSCH into the same uplink slot. By concatenating the feedback information within this unified transmission window, the system achieves accurate separate feedback for each UE type while avoiding the resource overhead of completely separate transmission occasions. This combining approach resolves the contradiction between feedback accuracy and resource efficiency.
3Reliability
If ACK/NACK feedbacks are transmitted in separate slots, then feedback reliability is improved, but feedback time increases
Solution Approach 1:
The patent combines multiple ACK/NACK feedback transmissions into a single uplink slot by concatenating the feedback information. This merging allows the system to maintain reliability through separate codebook tracking while reducing feedback time by eliminating the need for separate transmission slots. The concatenated feedback structure enables simultaneous delivery of both multi-user and unicast acknowledgments in one unified transmission.
Data Source
AI summary
Wireless communications systems and methods related to communicating ACK/NACK feedbacks for multi-user and unicast physical down-link shared channel (PDSCH) communications are provided. A UE may receive a multi-user PDSCH communication including a first transport block (TB) for the UE and may receive a unicast PDSCH communication including a second TB for the UE. The UE may determine a hybrid automatic repeat request (HARQ) codebook for the first TB associated with the multi-user PDSCH communication and the second TB associated with the unicast PDSCH communication. The UE may transmit a first acknowledgement/negative-acknowledgment (ACK/NACK) feedback for the first TB and a second ACK/NACK feedback for the second TB based on the determined HARQ codebook.