HARQ-ACK Codebook Indication for Carrier Aggregation
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Solution Overview
Problem
In the LTE system, user equipment and base stations have inconsistent understandings of the total original information bit quantity for hybrid automatic repeat request-acknowledgement (HARQ-ACK) across multiple downlink carriers, leading to decoding errors and increased complexity in blind detection.
Innovation Solution
A control information sending method that includes receiving and generating hybrid automatic repeat request-acknowledgement (HARQ-ACK) codebook indication information, which indicates the HARQ-ACK codebook size, and sending this information to ensure consistent understanding between devices, using a bit quantity of N with a difference of at least 2N+1, where N is a natural number greater than or equal to 2, to reduce decoding errors and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the total original information bit quantity of HARQ-ACK joint coding is calculated based on the quantity of PDSCHs detected by the UE, then the UE can generate HARQ-ACK feedback, but the UE and eNB have inconsistent understandings of the codebook size leading to decoding errors
Solution Approach 1:
The patent applies preliminary action by having the eNB pre-configure and indicate the HARQ-ACK codebook size to the UE before the actual data transmission. The eNB sends downlink control information (DCI) that includes the total quantity of PDSCHs it plans to send, allowing the UE to pre-calculate the correct codebook size. This ensures both parties have consistent understanding of the codebook size before HARQ-ACK feedback is generated, preventing decoding errors.
2Productivity
If the eNB sends multiple PDSCHs on multiple downlink carriers, then the data rate is improved, but the complexity of blind detection increases and decoding errors occur due to inconsistent codebook size understanding
Solution Approach 1:
The patent implements feedback mechanism where the eNB sends downlink control information (DCI) on each downlink carrier that includes information about the total quantity of PDSCHs to be transmitted. The UE uses this feedback information to accurately determine the HARQ-ACK codebook size. This feedback loop ensures that even with multiple carriers and PDSCHs, both eNB and UE have consistent understanding of the codebook size, enabling high data rates without increasing blind detection complexity.
3Quantity of substance
If the UE detects PDSCHs on multiple downlink carriers simultaneously, then the spectral efficiency is increased, but the UE may miss detecting some PDSCHs leading to inconsistent codebook size calculation
Solution Approach 1:
The patent applies preliminary action by having the eNB pre-indicate the total quantity of PDSCHs it plans to transmit across all downlink carriers through downlink control information (DCI). This preliminary information allows the UE to know in advance what the correct codebook size should be, regardless of whether the UE successfully detects all PDSCHs. Even if the UE misses detecting some PDSCHs due to the complexity of simultaneous multi-carrier detection, the pre-indicated total quantity ensures the UE calculates the correct codebook size, maintaining measurement precision.
Data Source
AI summary
Embodiments of the present invention provide a control information sending method and a communications device. The embodiments of the present invention can resolve a problem that user equipment and a base station device have inconsistent understandings of a total original information bit quantity of a HARQ-ACK of multiple downlink carriers.