Multicast HARQ Feedback Codebook for Separate DAI Counting
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Solution Overview
Problem
Existing wireless communication networks face challenges in supporting high spectral efficiency and reliability for multicast transmission due to the lack of effective Hybrid Automatic Repeat Request (HARQ) feedback mechanisms, particularly in 5G/NR networks, which affect applications requiring low packet error rates and low latency.
Innovation Solution
Implementing a dynamic codebook for HARQ feedback by associating downlink channels with unique Radio Network Temporary Identifiers (RNTIs) for unicast and multicast traffic, allowing separate counting of Downlink Assignment Indices (DAIs) for each traffic type, enabling efficient HARQ feedback even in carrier-aggregation scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If HARQ feedback is implemented for multicast transmission, then spectral efficiency is improved, but device complexity increases due to the need for separate DAI counting and dynamic codebook management
Solution Approach 1:
The patent segments the DAI counting process by introducing separate DAIs for unicast and multicast traffic. The network node transmits a first DAI for unicast traffic and a second DAI for multicast traffic, allowing the terminal device to count and manage HARQ codebooks separately for each traffic type. This segmentation resolves the contradiction by enabling efficient multicast HARQ feedback through structured organization rather than increasing overall system complexity.
2Measurement precision
If separate DAI counting is implemented for unicast and multicast traffic, then HARQ feedback accuracy is improved, but processing overhead increases
Solution Approach 1:
The patent merges the DAI information into a single downlink control information (DCI) message that contains both the first DAI for unicast traffic and the second DAI for multicast traffic. This combining approach allows the terminal device to extract and count both DAIs from one control message, thereby improving HARQ feedback accuracy for both traffic types while minimizing processing overhead by avoiding separate control messages.
3Adaptability or versatility
If dynamic codebook is used for HARQ feedback, then adaptability to different traffic conditions is improved, but system complexity increases due to flexible scheduling requirements
Solution Approach 1:
The patent implements dynamic codebook management where the HARQ codebook size and content are adjusted based on the actual number of unicast and multicast transport blocks received. The terminal device dynamically determines the codebook structure by counting the first DAI for unicast TBs and the second DAI for multicast TBs, allowing the system to adapt to varying traffic conditions while maintaining manageable complexity through rule-based dynamic adjustment.
Data Source
AI summary
Various embodiments of the present disclosure provide a method for multicast communication. The method which may be performed by a terminal device comprises receiving a first downlink channel including a first downlink assignment index from a network node. The first downlink channel is associated with a first traffic of the terminal device. The method further comprises determining that the first downlink assignment index is for the first traffic, according to the association between the first downlink channel and the first traffic. According to various embodiments of the present disclosure, hybrid automatic repeat request feedback may be implemented efficiently and flexibly for different traffics such as multicast and unicast traffics.