HARQ-ACK Mapping in LTE-A TDD Carrier Aggregation
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Solution Overview
Problem
In LTE-A TDD systems with carrier aggregation, the existing methods for transmitting HARQ-ACK information over PUSCH result in the transmission of invalid information when uplink and downlink configurations of aggregated serving cells are different, affecting the performance of HARQ-ACK and data transmission.
Innovation Solution
A method and apparatus that determine the number of downlink subframes for each serving cell based on the uplink and downlink configurations and DAI signaling in the DCI format 0/4, allowing accurate mapping and encoding of HARQ-ACK information to avoid sending invalid data, using PUCCH format 3 to transmit HARQ-ACK information over PUSCH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing HARQ-ACK transmission method is used in LTE-A TDD with carrier aggregation, then the system can transmit HARQ-ACK information over PUSCH, but invalid HARQ-ACK information is transmitted when uplink and downlink configurations of aggregated serving cells are different, affecting transmission performance
Solution Approach 1:
The patent changes the parameter of determining the number of downlink subframes based on the specific uplink and downlink configurations of each serving cell. By calculating the number of downlink subframes individually for each cell configuration and using the minimum value across all cells, the system adapts to different configuration scenarios and prevents transmission of invalid HARQ-ACK information while maintaining reliable communication.
2Ease of manufacture
If the number of downlink subframes is determined without considering specific cell configurations, then the transmission process is simple, but the number of bits in HARQ-ACK information does not align with actual feedback requirements
Solution Approach 1:
The patent performs preliminary calculation of the number of downlink subframes for each serving cell based on their specific uplink and downlink configurations before determining the final number of bits to transmit. This preliminary action ensures that the HARQ-ACK information bit count is precisely aligned with the actual feedback requirements of each cell, preventing both information loss and unnecessary transmission overhead.
Data Source
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AI summary
Provided are a method and apparatus for sending Hybrid Automatic Repeat Request Acknowledge (HARQ-ACK) information. The method includes: when a terminal employs a physical uplink control channel (PUCCH) format 3 to transmit HARQ-ACK information and the HARQ-ACK information is transmitted over a uplink physical shared channel (PUSCH), determining the number of downlink subframes for serving cells to feed back the HARQ-ACK information; determining the number of encoded modulated symbols required for sending the HARQ-ACK information according to the determined number of downlink subframes; and mapping the HARQ-ACK information to be sent to the PUSCH of a specified uplink subframe according to the number of encoded modulated symbols and sending the HARQ-ACK information. The technical solutions provided by the present invention are applied to improve the performance of the HARQ-ACK information, and thus improve the data performance.