HARQ Codebook Ordering for Multiple DL SPS Feedback
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Solution Overview
Problem
The challenge in 5G NR communication systems is handling HARQ ACK/NACK feedback for multiple DL SPS configurations with overlapping time domain resource allocations, which is not efficiently addressed by existing Type 1 and Type 2 HARQ codebooks in Rel-15, particularly in scenarios with multiple simultaneous SPS configurations and overlapping transmissions.
Innovation Solution
The proposed solution involves constructing a semi-static HARQ codebook with separate entries for overlapping time domain resource allocations, ordering HARQ A/N bits based on SPS configuration indices, and multiplexing them with dynamically scheduled PDSCHs, allowing for efficient HARQ feedback even in cases of overlapping time domain resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Type 1 or Type 2 HARQ codebooks from Rel-15 are used, then HARQ feedback can be provided for single SPS configuration, but they cannot efficiently handle multiple DL SPS configurations with overlapping time domain resource allocations
Solution Approach 1:
The patent segments the HARQ codebook into separate sub-codebooks for each DL SPS configuration. Each sub-codebook handles HARQ feedback for a specific SPS configuration independently, allowing the system to manage multiple overlapping SPS configurations without conflict. This segmentation enables reliable HARQ feedback for each configuration while maintaining overall system adaptability.
2Adaptability or versatility
If multiple DL SPS configurations are supported with overlapping time domain resources, then service diversity (e.g., eMBB and URLLC) can be served simultaneously, but HARQ feedback collisions occur in existing codebook structures
Solution Approach 1:
The patent introduces a new dimension for organizing HARQ feedback by creating separate codebook structures in the feedback domain for each SPS configuration. Instead of trying to fit all feedback into a single codebook structure, the system uses multiple parallel codebook dimensions, each dedicated to a specific SPS configuration. This dimensional separation prevents feedback collisions while enabling simultaneous support for diverse services with different QoS requirements.
3Ease of manufacture
If existing HARQ codebook structures are used for multiple SPS configurations, then implementation is simple, but HARQ ACK/NACK feedback cannot be properly ordered and multiplexed with dynamically scheduled PDSCHs
Solution Approach 1:
The patent applies preliminary action by establishing a predetermined ordering rule for HARQ feedback bits based on SPS configuration indices before the actual feedback transmission. Each SPS configuration is assigned a specific index, and the codebook is constructed by concatenating sub-codebooks in ascending order of these indices. This preliminary ordering simplifies the multiplexing process with dynamically scheduled PDSCHs, as the feedback structure is already organized and ready for efficient transmission without complex runtime ordering operations.
Data Source
AI summary
Systems and methods for constructing a Hybrid Automatic Repeat Request (HARQ) codebook are provided. In some embodiments, a method performed by a User Equipment (UE) includes constructing a dynamic HARQ codebook with a first set of HARQ ACK bits being associated with dynamically scheduled Physical Downlink Shared Channels (PDSCHs) and a second set of HARQ ACK bits being associated with Semi-Persistent Scheduling (SPS) PDSCHs; and ordering the second set of HARQ ACK bits according to the SPS PDSCH index. In some embodiments, the UE receives, from a network node, a plurality of downlink SPS PDSCHs, each with a SPS configuration index and the UE sends, to the network node, HARQ ACK feedback associated with the SPS PDSCHs. In this way, HARQ ACK feedback is enabled for multiple DL SPS configured for a UE with possibly overlapping time domain resource allocations.