HARQ Codebook Construction with Per-Process Feedback Control
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Solution Overview
Problem
Current Hybrid Automatic Repeat Request (HARQ) procedures in 5G NR are inadequate for satellite communications due to large propagation delays, as they require a substantial increase in the number of HARQ processes, which is challenging to support due to memory and signaling overhead constraints.
Innovation Solution
Implementing dynamic HARQ codebook construction that enables or disables HARQ Acknowledgment (HARQ-ACK) feedback on a per-HARQ process basis, allowing for configuration of both feedback-enabled and feedback-disabled processes, thereby optimizing HARQ codebook construction and reducing overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of HARQ processes is increased to accommodate large propagation delays in satellite communications, then the system can maintain proper HARQ operation, but memory overhead and signaling complexity increase substantially
Solution Approach 1:
The patent segments HARQ processes into two distinct groups: feedback-enabled HARQ processes and feedback-disabled HARQ processes. This segmentation allows the system to maintain multiple HARQ processes for reliability while managing feedback overhead by selectively disabling feedback for certain processes, thus resolving the contradiction between maintaining reliable HARQ operation and reducing memory/signaling overhead.
Solution Approach 2:
Instead of enabling feedback for all HARQ processes, the patent applies partial action by enabling feedback only for a subset of HARQ processes that require it, while disabling feedback for others where it is not necessary. This reduces the overall feedback overhead and memory requirements while maintaining sufficient HARQ reliability for satellite communications.
2Reliability
If HARQ feedback is enabled for all HARQ processes, then complete error correction is achieved, but feedback overhead increases significantly
Solution Approach 1:
The patent extracts the feedback mechanism from the overall HARQ system and applies it selectively only to specific HARQ processes that require error correction, rather than universally to all processes. This extraction allows the system to maintain error correction capability where needed while eliminating unnecessary feedback overhead for processes where it is not required.
Solution Approach 2:
The patent implements partial feedback by enabling HARQ-ACK feedback for only a subset of HARQ processes (feedback-enabled group) while disabling it for others (feedback-disabled group). This partial application of feedback reduces the total feedback overhead while maintaining sufficient error correction reliability for critical transmissions.
3Measurement precision
If the HARQ codebook includes all PDSCHs regardless of feedback configuration, then complete tracking is achieved, but codebook size and processing complexity increase
Solution Approach 1:
The patent segments the HARQ codebook construction process to differentiate between feedback-enabled and feedback-disabled HARQ processes. The UE constructs codebooks selectively based on the feedback configuration of each HARQ process, including only those PDSCHs associated with feedback-enabled processes in the HARQ-ACK codebook, thereby reducing codebook size and processing complexity while maintaining accurate tracking of relevant transmissions.
Data Source
AI summary
Systems and methods are disclosed for dynamic Hybrid Automatic Repeat Request (HARQ) codebook construction with enabling or disabling of HARQ Acknowledgment (HARQ-ACK) feedback per HARQ process. In one embodiment, a method performed by a wireless communication device comprises receiving, from a network node, information that configures the wireless communication device with a first set of HARQ processes for which HARQ-ACK feedback is disabled and a second set of HARQ processes for which HARQ-ACK feedback is enabled. The method further comprises receiving first downlink control information that schedules a first downlink shared channel transmission and determining that the transmission corresponds to one of the first set of HARQ processes for which HARQ-ACK feedback is disabled. The method further comprises, upon making this determination, performing a first set of actions for HARQ-ACK feedback generation for HARQ processes with HARQ-ACK feedback disabled.