Dynamic HARQ Codebook Sizing via PUCCH Configuration
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Solution Overview
Problem
In carrier aggregation systems, the existing HARQ codebook configuration leads to high overhead, especially when a large number of component carriers are configured but only a few are scheduled, resulting in inefficient HARQ codebook size and potential errors when missing the last downlink assignment.
Innovation Solution
The proposed solution involves identifying the Physical Uplink Control Channel (PUCCH) resource within the downlink assignment, which includes a PUCCH timing indicator and ACK/NACK resource indicator, to dynamically configure the HARQ codebook size, thereby avoiding errors and optimizing codebook size based on actual DL assignments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a semi-statically configured HARQ codebook is used to include feedback of all configured/activated component carriers, then the HARQ codebook is simple and robust, but the overhead becomes high when many component carriers are configured but only a few are scheduled
Solution Approach 1:
The patent applies dynamics by transitioning from a static HARQ codebook configuration to a dynamic one. The codebook size is no longer fixed based on all configured component carriers but adapts according to the actual number of scheduled component carriers. This is achieved through dynamic signaling mechanisms that indicate which component carriers are currently scheduled, allowing the codebook to be resized accordingly and reducing overhead when fewer carriers are active.
Solution Approach 2:
The patent changes the parameter of codebook size from a fixed value to a variable that depends on the scheduling state. By introducing parameters such as the number of scheduled component carriers and using these to dynamically adjust the codebook dimensions, the system optimizes the balance between reliability and overhead. The codebook size becomes a function of actual scheduling requirements rather than a static configuration.
2Device complexity
If a semi-statically configured HARQ codebook is used, then the configuration is simple, but it leads to high overhead when not all component carriers are scheduled
Solution Approach 1:
The patent introduces dynamic adaptation mechanisms that allow the codebook size to change based on scheduling conditions. While the basic configuration remains simple, the system dynamically adjusts the codebook dimensions by monitoring which component carriers are scheduled and using this information to resize the codebook accordingly, thereby reducing overhead without complicating the fundamental configuration approach.
Solution Approach 2:
The patent employs preliminary action by pre-configuring the maximum codebook size and having the system dynamically scale down from this maximum when fewer component carriers are scheduled. This approach maintains simplicity by having a predetermined upper bound while allowing efficient reduction of actual codebook size based on current scheduling needs, avoiding the complexity of completely adaptive configuration.
3Stability of the object's composition
If the HARQ codebook size is fixed based on configured component carriers, then the codebook structure is stable, but errors occur when the last downlink assignment is missed
Solution Approach 1:
The patent implements feedback mechanisms that allow the system to detect and correct errors related to missed downlink assignments. By incorporating acknowledgment feedback and using the scheduled component carrier information to verify codebook construction, the system can identify when assignments are missed and adjust accordingly, thereby maintaining both structural stability and feedback accuracy.
Solution Approach 2:
The patent introduces dynamic verification mechanisms that check whether the actual number of scheduled component carriers matches the codebook size. This dynamic checking allows the system to detect inconsistencies that may indicate missed assignments and trigger appropriate error handling procedures, maintaining reliability while preserving the stability of the codebook structure.
Data Source
AI summary
According to certain embodiments, a method by a wireless device for transmitting Hybrid Automatic Repeat Request (HARQ) feedback includes obtaining a Physical Uplink Control Channel (PUCCH) configuration parameter comprising a channel code type. Based on the PUCCH configuration parameter comprising the channel code type, a PUCCH format is selected for transmitting the HARQ feedback to a network node on the PUCCH, and the HARQ feedback is transmitted to the network node.