HARQ-ACK Index Mapping for Inter-band TDD Channel Selection
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Solution Overview
Problem
The conventional Rel-10 channel selection transmission method in TDD systems faces errors due to different PDSCH HARQ timings between the PCell and the SCell, leading to inefficiencies in PUCCH transmission.
Innovation Solution
A method is introduced to handle PUCCH transmission by identifying the number of downlink subframes for both PCell and SCell, generating DTX response information, and mapping HARQ-ACK information accordingly to ensure accurate transmission across different TDD configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different TDD configurations are used for PCell and SCell to increase system capacity and flexibility, then adaptability and versatility are improved, but errors in PUCCH transmission occur due to timing mismatches
Solution Approach 1:
The patent segments the HARQ-ACK codebook into multiple parts, with each part corresponding to a specific serving cell (PCell or SCell). This segmentation allows independent handling of timing relationships for each cell, resolving the timing mismatch issue while maintaining support for different TDD configurations across cells.
Solution Approach 2:
The patent introduces a timing relationship parameter (k value) as an intermediary to coordinate the timing between PCell and SCell downlink subframes and the uplink subframe. By using this intermediary parameter, the system can maintain reliable PUCCH transmission even when different TDD configurations are applied to different cells.
2Device complexity
If conventional channel selection transmission method is used, then device complexity is kept low, but transmission errors occur due to timing mismatches between PCell and SCell
Solution Approach 1:
The patent dynamically determines the HARQ-ACK codebook structure based on the actual timing relationships between downlink and uplink subframes. The codebook generation adapts to different k values and TDD configurations, maintaining reliability without requiring overly complex fixed structures.
Solution Approach 2:
The patent changes the parameter representation by introducing explicit timing relationship parameters (k values) that define the association between downlink subframes and uplink subframes. This parameter-based approach allows flexible handling of timing mismatches while keeping the transmission method manageable in complexity.
3Loss of information
If HARQ-ACK information is transmitted for all downlink subframes, then information completeness is improved, but transmission time and resource consumption increase
Solution Approach 1:
The patent applies partial action by generating HARQ-ACK information only for the necessary subset of downlink subframes based on their timing relationships with the uplink subframe. Using the k value parameter, the system identifies which downlink subframes need ACK/NACK feedback, avoiding unnecessary transmissions and reducing time consumption while maintaining information completeness.
Data Source
AI summary
Hybrid Automatic Retransmit ReQuest-Acknowledgment (HARQ-ACK) index mapping and uplink resource allocation is performed and controlled for channel selection transmission. A method for transmitting HARQ-ACK information to an eNode-B (eNB) by a User Equipment (UE) includes identifying KPCell as a number of downlink subframe(s) of a PCell associated with an uplink subframe and identifying KSCell as a number of downlink subframe(s) of an SCell associated with the uplink subframe; generating Discontinuous Transmission (DTX) response information for a cell having a smaller number of downlink subframes between the PCell and the SCell; generating HARQ-ACK information including the generated DTX response information and response information on data received by the UE from the eNB; and transmitting the generated HARQ-ACK information to the eNB through the uplink subframe.