HARQ Feedback Control for TDD-FDD Carrier Aggregation
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Solution Overview
Problem
In carrier aggregation systems, there is a lack of mechanisms for appropriate transmission and reception of HARQ response information between TDD and FDD cells, leading to inefficient communication.
Innovation Solution
A terminal device and base station apparatus are designed to transmit and receive HARQ response information on a physical uplink shared channel, using specific expressions to determine the number of subframes required for feedback, based on the downlink control information format and the configuration of serving cells with different frame constitution types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If carrier aggregation is performed with TDD and FDD cells having different frame constitution types, then communication flexibility and bandwidth utilization are improved, but HARQ response information transmission and reception cannot be appropriately performed
Solution Approach 1:
The patent segments the handling of HARQ response information by separating TDD cells and FDD cells into distinct processing paths. Each cell type has its own specific procedures for transmitting and receiving HARQ responses, allowing the system to maintain reliability for each cell type while supporting both types simultaneously in carrier aggregation.
Solution Approach 2:
The patent applies different frame constitution type-specific procedures to different cells based on their local characteristics. TDD cells use TDD-appropriate HARQ timing and transmission methods, while FDD cells use FDD-appropriate methods, allowing each cell to operate optimally within the carrier aggregation context.
2Device complexity
If a mechanism for HARQ response information transmission between different frame constitution types is not provided, then system complexity is reduced, but communication efficiency deteriorates
Solution Approach 1:
The patent divides the HARQ transmission mechanism into cell-type-specific segments rather than implementing a single unified mechanism. This segmentation avoids the complexity of designing a universal mechanism that handles all frame constitution types, while still achieving efficient communication by optimizing each segment for its specific cell type.
Solution Approach 2:
The patent changes operational parameters (such as HARQ timing, transmission timing, and resource allocation) based on the frame constitution type of each cell. This allows the system to maintain simpler cell-type-specific mechanisms while achieving high communication efficiency through parameter optimization for each cell type.
Data Source
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AI summary
There is provided a terminal device which includes a transmission unit that transmits HARQ response information to a first serving cell and a second serving cell on a physical uplink shared channel in a subframe n. The physical uplink shared channel is transmitted based on a physical downlink control channel or an enhanced physical downlink control channel which is detected in a state of including a downlink control information format 0/4. Two or more serving cells are configured in the terminal device, in a case where frame constitution types of any two configured serving cells are different from each other, and in a case where a primary cell has Frame constitution type 2, BcDL is applied to the first serving cell of Frame constitution type 2 by using the following expression (1), and is applied to the second serving cell of Frame constitution type 1 by using the following expression (2). [Math. 1] BcDL=minWDAIULMc [Math. 2] BcDL=minWDAIUL+4⌈U−WDAIUL/4⌉,Mc