Dynamic HARQ Codebook Allocation for Multi-Cell Energy Saving
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Solution Overview
Problem
Current HARQ ACK feedback mechanisms in wireless communication systems are inefficient due to the large size of semi-static HARQ ACK codebooks and failure to consider cell operating states, leading to increased complexity and resource utilization, especially when managing multiple component carriers and cells in discontinuous transmission (DTX)/discontinuous reception (DRX) states.
Innovation Solution
The optimization of Type 1 HARQ-ACK codebooks by removing physical downlink shared channel (PDSCH) occasions during cell DTX active time and dynamically allocating codebook entries based on the operating state of each component carrier, reducing unnecessary feedback for inactive cells and improving resource efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If semi-static HARQ ACK codebooks are used for multi-cell feedback, then comprehensive coverage of all cells is achieved, but signaling overhead and system complexity increase significantly
Solution Approach 1:
The patent applies dynamics by transitioning from static semi-static codebooks to dynamic codebook generation. The network entity determines codebook entries based on real-time operating states of component carriers, allowing the codebook to adapt its size and content dynamically. This resolves the contradiction by making the codebook flexible - comprehensive when needed, compact when not needed.
Solution Approach 2:
The patent changes the parameter of codebook entry allocation from fixed to variable based on operating state. By using configuration parameters that indicate operating states (active, inactive, DTX, DRX), the system dynamically adjusts which codebook entries are allocated. This parameter change allows the codebook to maintain reliability for active cells while reducing complexity by excluding inactive cells.
2Loss of information
If HARQ ACK feedback includes all component carriers, then complete feedback information is provided, but resource utilization decreases due to unnecessary feedback for inactive cells
Solution Approach 1:
The patent extracts only the necessary feedback information by removing codebook entries for inactive component carriers. The network entity identifies which cells are currently active and allocates codebook entries only for those cells. This extraction principle maintains feedback completeness for active cells while eliminating waste of resources on inactive cells.
Solution Approach 2:
The patent applies partial action by providing feedback only for the subset of active component carriers rather than all configured carriers. The operating state parameters enable the system to perform partial feedback transmission, which is sufficient for maintaining communication quality while conserving energy and resources.
3Ease of manufacture
If fixed codebook configurations are used for all cells, then configuration simplicity is maintained, but adaptability to different cell states (DTX, DRX, active) is reduced
Solution Approach 1:
The patent introduces dynamics into the configuration process by using operating state parameters that reflect real-time cell conditions. The network entity allocates codebook entries based on current states (active, inactive, DTX, DRX), making the configuration adaptive rather than fixed. This maintains simplicity through automated state-based allocation while achieving high adaptability to different cell states.
Solution Approach 2:
The patent uses configuration parameters indicating operating states to dynamically adjust codebook allocation. By changing the allocation parameters based on cell state, the system achieves adaptability without complex manual reconfiguration. The parameter-driven approach maintains ease of implementation while providing versatility across different operational scenarios.
Data Source
AI summary
A method for wireless communication at a user equipment (UE) and related apparatus are provided. In the method, the UE receives a set of configuration parameters related to a hybrid automatic repeat request (HARQ) acknowledgement (ACK) codebook from a network entity, and identifies an operating state for each component carrier (CC) of multiple CCs associated with the UE based on the set of configuration parameters. The UE further allocates one or more entries of the HARQ ACK codebook based on the operating state for each CC of the multiple CCs, and transmits the HARQ ACK feedback associated with the one or more entries of the HARQ ACK codebook to the network entity.