HARQ-ACK Transmission Timing in TDD Carrier Aggregation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems supporting Time Division Duplex (TDD) with multiple carriers, existing technologies face challenges in efficiently transmitting and receiving signals due to differing Uplink-Downlink (UL-DL) configurations across carriers, leading to complexities in signal transmission and reception timings.
Innovation Solution
A method and apparatus for a user equipment (UE) in a TDD wireless communication system, where the UE configures multiple serving cells with different UL-DL configurations, receives Hybrid Automatic Repeat request (HARQ)-ACK responses in multiple subframes, and transmits these responses only in subframes configured as uplink in all serving cells, using a specific subframe determined by the Downlink Association Set Index (DASI) of the serving cell with the largest number of DL subframes, and skips decoding of Physical Downlink Shared Channel (PDSCH) in subframes not configured as downlink for all cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple serving cells with different UL-DL configurations are configured, then carrier aggregation capability is improved, but HARQ-ACK transmission timing complexity increases
Solution Approach 1:
The patent applies local quality by allowing different UL-DL configurations (different qualities of time resource allocation) for different serving cells in the carrier aggregation. Each cell can have its own configuration optimized for its specific traffic pattern and channel conditions, while the UE handles the complexity of coordinating HARQ-ACK transmissions across these differently configured cells through standardized procedures.
2Reliability
If HARQ-ACK responses are transmitted in all subframes, then acknowledgment coverage is improved, but uplink resource consumption increases
Solution Approach 1:
The patent implements periodic action by transmitting HARQ-ACK responses only in periodically occurring uplink subframes that are configured for uplink transmission across all serving cells. Instead of continuous transmission in every subframe, the system uses periodic uplink opportunities (according to the TDD UL-DL configuration) to send acknowledgments, thereby reducing uplink resource consumption while maintaining reliable acknowledgment coverage through the periodic nature of transmissions.
3Productivity
If PDSCH decoding is performed in all subframes, then downlink data reception is improved, but processing overhead increases
Solution Approach 1:
The patent applies partial action by performing PDSCH decoding only in subframes that are configured as downlink subframes in the UE's TDD UL-DL configuration. Instead of attempting to decode PDSCH in all subframes regardless of configuration, the UE selectively processes only those subframes where downlink transmission is expected according to its configuration, thereby reducing processing overhead while maintaining complete downlink data reception capability for all configured cells.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Abstract: The present invention relates to a wireless communication system. More particularly, the present invention relates to a method for transmitting uplink control information and a device therefor, the method comprising the steps of: forming a plurality of serving cells each having different UL-DL configurations; receiving one or more signals requiring a HARQ-ACK response from M(M≥ 1) number of subframes; and executing the process for transmitting the HARQ-ACK response to the one or more signals in a specific subframe corresponding to the M number of subframes, wherein, only when the specific subframe is set as an uplink in all of the plurality of serving cells, the HARQ-ACK response to the one or more signals are transmitted through the specific subframe.