Counter-DAI HARQ Feedback for Reliable Multicast PDSCH Scheduling
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently managing Hybrid Automatic Repeat Request (HARQ) feedback control for multicast and group-based services, particularly in ensuring reliable decoding and scheduling of HARQ bits across multiple PDSCH receptions.
Innovation Solution
The proposed solution involves configuring user equipment (UE) and base stations to decode multiple DCIs using group identification (IDs) to obtain downlink assignment indexes (DAIs), generate HARQ bits for PDSCH receptions, and arrange these bits in a HARQ codebook, with positions indicated by counter DAIs, to facilitate accurate HARQ feedback and resource coordination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple DCIs are scheduled for multicast PDSCH receptions, then the scheduling flexibility and service coverage are improved, but the complexity of managing HARQ feedback and ensuring correct bit arrangement increases
Solution Approach 1:
The patent implements a feedback mechanism where the base station includes counter DAI values in DCI messages to guide the UE in correctly arranging HARQ bits in the codebook. The UE feeds back HARQ-ACK information based on the indicated positions, and the base station uses this feedback to determine successful receptions and schedule retransmissions as needed.
Solution Approach 2:
The counter DAI acts as an intermediary parameter that bridges the scheduling decisions at the base station and the HARQ bit arrangement at the UE. This intermediary mechanism allows the base station to control the structure of HARQ feedback without requiring complex processing at the UE side.
2Reliability
If HARQ bits are arranged in a codebook with positions indicated by counter DAI, then the reliability of HARQ feedback is improved, but the processing overhead and signaling requirements increase
Solution Approach 1:
The patent changes the parameter representation by using counter DAI values to indicate positions of HARQ bits in the codebook. Instead of using explicit position indicators or complex mapping rules, the system uses the counter DAI parameter to implicitly define the arrangement, reducing signaling overhead while maintaining reliability.
3Productivity
If the base station monitors HARQ-ACK codebooks from multiple UEs, then the service coverage and multicast efficiency are improved, but the difficulty of decoding and identifying correct HARQ bits increases
Solution Approach 1:
The patent segments the HARQ feedback from multiple UEs into individually identifiable codebooks by using group RNTI for scrambling and counter DAI for position indication. Each UE's HARQ bits are arranged in a specific sequence within the codebook, allowing the base station to decode and identify bits from different UEs separately, even when received simultaneously.
Data Source
AI summary
The present disclosure is related to techniques for Hybrid Automatic Repeat Request (HARQ) feedback control which can be used with a multicast service or any group-based service. In an embodiment, a UE is configured to decode a first DCI and a second DCI by using a first group identification (ID) to obtain a first downlink assignment index (DAI) and a second DAI respectively; decode a first PDSCH reception scheduled by the first DCI to generate a first HARQ bit, and decode a second PDSCH reception scheduled by the second DCI to generate a second HARQ bit; and arrange the first and the second HARQ bits for the first and the second PDSCH receptions in a first HARQ codebook, wherein a first position of the first HARQ bit in the first HARQ codebook is indicated by a first counter DAI (C-DAI) included in the first DAI, and a second position of the second HARQ bit in the first HARQ codebook is indicated by a second C-DAI included in the second DAI.