HARQ-ACK Transmission Across Mixed Duplexing Mode Carriers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the 3GPP LTE system, the existing carrier aggregation technology faces challenges in transmitting hybrid automatic repeat request-acknowledgement (HARQ-ACK) information across carriers with different duplexing modes, leading to resource wastage due to mismatched uplink and downlink subframes, particularly when FDD and TDD carriers are aggregated.
Innovation Solution
The method involves adjusting the uplink subframe alignment for HARQ-ACK transmission by using a physical uplink control channel (PUCCH) on either the first or second serving cell based on the duplexing mode of each serving cell, ensuring that all downlink subframes have corresponding uplink subframes for HARQ-ACK feedback, regardless of the duplexing mode, thereby optimizing resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If HARQ-ACK timing of FDD (n+4) is used when FDD carrier is aggregated with TDD carrier, then HARQ-ACK timing is simple and consistent, but there is no corresponding uplink subframe on TDD carrier for some downlink subframes, causing resource waste
Solution Approach 1:
The patent segments uplink subframes into two sets: a first uplink subframe set for transmitting HARQ-ACK of TDD carrier, and a second uplink subframe set for transmitting HARQ-ACK of FDD carrier. This segmentation allows each carrier type to use appropriate uplink subframes, resolving the conflict between timing consistency and resource utilization.
Solution Approach 2:
Different uplink subframe sets are assigned different functions based on local requirements: the first set handles TDD HARQ-ACK with TDD timing characteristics, while the second set handles FDD HARQ-ACK with FDD timing characteristics (n+4). This local quality differentiation optimizes resource utilization for each carrier type.
2Device complexity
If HARQ-ACK is sent only on primary carrier in existing CA system, then system complexity is low, but it cannot efficiently support aggregation of different duplexing modes
Solution Approach 1:
The patent enables both TDD and FDD carriers to serve as PUCCH carriers for HARQ-ACK transmission. The determination rule selects which carrier transmits HARQ-ACK based on subframe configuration, making the system universal in supporting different duplexing modes while maintaining efficient resource utilization.
Solution Approach 2:
The patent introduces dynamic selection of PUCCH carrier based on subframe index and uplink subframe set configuration. The system dynamically determines which carrier (TDD or FDD) transmits HARQ-ACK in each uplink subframe, providing adaptability for different duplexing mode aggregations without increasing overall system complexity.
3Loss of energy
If uplink subframes are not properly aligned with downlink subframes for HARQ-ACK feedback, then resource utilization improves, but HARQ-ACK timing for FDD carriers changes
Solution Approach 1:
By segmenting uplink subframes into two distinct sets with different functions, the patent preserves FDD HARQ-ACK timing (n+4) for FDD carriers while ensuring proper alignment for TDD carriers. This segmentation prevents timing changes while optimizing resource utilization.
Solution Approach 2:
The patent introduces an intermediary mechanism (uplink subframe set configuration and determination rules) that mediates between FDD and TDD timing requirements. This intermediary layer allows both timing requirements to be satisfied simultaneously by routing HARQ-ACK through appropriate uplink subframe sets.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Embodiments of the present invention provide an uplink control information transmission method, a base station, and user equipment. The method includes: receiving, by UE in a downlink subframe N, a downlink control channel sent by a base station; sending, by the UE, a hybrid automatic repeat request-acknowledgement corresponding to the downlink control channel to the base station in an uplink subframe N+4 by using a PUCCH, where when the uplink subframe N+4 belongs to a first uplink subframe set, the PUCCH is carried on a second serving cell of the UE, and when the uplink subframe N+4 belongs to a second uplink subframe set, the PUCCH is carried on the first serving cell, where a duplexing mode of the first serving cell is different from a duplexing mode of the second serving cell. By means of the foregoing method, a problem of how to transmit an HARQ-ACK during aggregation of carriers of different duplexing modes is resolved, so that all downlink subframes have corresponding uplink subframes used to feed back an HARQ-ACK, which improves resource utilization, and HARQ-ACK timing of an FDD carrier is not changed.