Joint HARQ Feedback for Multi-TRP PDSCH via CORESET Grouping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a need to determine how to construct a semi-static Hybrid Automatic Repeat Request (HARQ) codebook for joint HARQ-ACK feedback in New Radio (NR) systems when multiple Downlink Shared Channels (PDSCHs) are received from different Transmission Reception Points (TRPs) using multiple Downlink Control Information (DCIs, as current methods do not adequately address how to multiplex A/N bits associated with these PDSCHs.
Innovation Solution
A method for constructing a Type-1 HARQ codebook is proposed, where the HARQ-ACK bits for PDSCHs received from different TRPs are determined based on the Control Resource Set (CORESET) group identifier of the DCI, allowing for joint HARQ-ACK feedback with minimal increase in overhead, by configuring the UE with PDSCH-to-HARQ-feedback timing and time domain resource allocations, and using explicit or implicit signaling to allocate entries in the codebook.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate HARQ-ACK feedback is used for PDSCHs from different TRPs, then reliability of feedback is improved, but device complexity and overhead increase
Solution Approach 1:
The patent combines HARQ-ACK feedback for multiple PDSCHs from different TRPs into a single joint feedback mechanism. The UE constructs a unified HARQ codebook that includes acknowledgment bits for all received PDSCHs regardless of which TRP transmitted them, thereby reducing feedback overhead and simplifying the feedback mechanism while maintaining reliable communication across multiple TRPs
2Quantity of substance
If joint HARQ-ACK feedback is used for multiple TRPs, then feedback overhead is reduced, but difficulty of detecting and measuring increases
Solution Approach 1:
The patent segments the HARQ feedback process by introducing CORESET group identifiers to distinguish between different TRPs. Each CORESET is associated with a group identifier, and the UE uses this segmentation to determine which TRP transmitted each PDSCH. This segmentation enables the UE to construct the joint HARQ codebook by processing feedback bits in organized segments according to TRP groups, thereby reducing the difficulty of measuring and detecting feedback information
3Ease of manufacture
If NR Rel-15 procedure is reused for HARQ codebook construction, then ease of manufacture is improved, but adaptability worsens
Solution Approach 1:
The patent extends the NR Rel-15 HARQ codebook construction procedure to serve multiple TRPs simultaneously. By making the procedure universal, the same basic algorithm used in single-TRP scenarios can be applied to multi-TRP scenarios without requiring entirely new implementation. The UE determines TRP identity using CORESET group identifiers and incorporates this information into the existing codebook construction process, thereby maintaining implementation simplicity while achieving adaptability to multi-TRP operations
Data Source
AI summary
Systems and methods for joint Hybrid Automatic Repeat Request (HARQ) feedback for Physical Downlink Shared Channel (PDSCH) transmission over multiple TRPs are provided. In some embodiments, a method performed by a wireless device for enabling transmission feedback includes: receiving a first Transport Block (TB) and a second TB; and determining the first TB and the second TB based on a Control Resource Set (CORESET) group identifier of a CORESET over which a corresponding Downlink Control Information (DCI) scheduling the TB is received. In this way, the New Radio (NR) Rel-15 procedure for type 1 HARQ codebook construction might be reused with the same or minimum increase of HARQ feedback overhead with semi-static HARQ-ACK codebook.