Carrier Aggregation HARQ-ACK Timing for Variable Slot Durations
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Solution Overview
Problem
The existing LTE/LTE-A communication systems require improvements in carrier aggregation operations to support aggregation of different carrier types, particularly in next-generation communication systems, to enhance data rates and handle diverse bandwidth reception capabilities and transmission durations.
Innovation Solution
The solution involves enabling multiplexing of physical downlink control channel transmissions across varying system bandwidths, supporting carrier aggregation with different transmission durations, designing hybrid automatic repeat request acknowledgement codebooks, and implementing transmission power control processes for overlapping transmissions with prioritization mechanisms to manage power allocation for multiple traffic services with differing reliability requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If carrier aggregation supports aggregation of different carrier types with varying transmission durations, then the system can serve UEs with different bandwidth reception capabilities and enhance data rates, but the complexity of determining HARQ-ACK codebooks and managing power control increases
Solution Approach 1:
The patent segments the carrier aggregation into different groups based on transmission duration. First group of cells uses first duration (e.g., 1 slot) while second group of cells uses second duration (e.g., 2 slots). This segmentation allows independent HARQ-ACK codebook determination for each group, reducing the complexity of handling mixed-duration carriers.
Solution Approach 2:
The patent introduces dynamic HARQ-ACK codebook determination where the codebook size and structure are adjusted based on the actual transmission durations detected in each slot. The UE dynamically determines the codebook by identifying which cells transmitted for first duration and which for second duration, allowing flexible adaptation without fixed complex configurations.
2Productivity
If the UE simultaneously transmits on multiple cells with different durations, then data rate is enhanced, but transmission power control becomes complex due to overlapping transmissions
Solution Approach 1:
The patent segments power control into separate processes for different transmission duration groups. First power control process manages power for first duration transmissions while second power control process manages power for second duration transmissions. This segmentation allows independent power adjustment for each group, simplifying the overall power control complexity.
Solution Approach 2:
The patent applies preliminary power control adjustments based on predicted transmission durations before actual transmissions occur. The UE is configured with power control parameters for different durations in advance, allowing the UE to prepare appropriate power levels before the actual transmission slot, reducing real-time control complexity.
3Reliability
If the UE transmits HARQ-ACK feedback for multiple cells with different durations, then feedback completeness is improved, but the time required for feedback transmission increases
Solution Approach 1:
The patent segments HARQ-ACK feedback into separate codebooks for different transmission duration groups. First HARQ-ACK codebook contains feedback for first duration transmissions while second HARQ-ACK codebook contains feedback for second duration transmissions. This segmentation allows parallel processing and transmission of feedback for different cell groups, reducing total feedback time.
Solution Approach 2:
The patent implements periodic HARQ-ACK feedback transmission where feedback for different duration groups is transmitted in periodic intervals. The UE transmits HARQ-ACK feedback for first duration cells in one feedback opportunity and for second duration cells in subsequent opportunities, allowing time-efficient feedback delivery while maintaining completeness.
Data Source
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AI summary
A method performed by a terminal in a wireless communication system, the method comprising: receiving, from a base station, first downlink control information, DCI, scheduling a first physical downlink shared channel, PDSCH, on a serving cell, the first DCI including first information on a slot offset between the first PDSCH and a first hybrid automatic repeat request acknowledgement, HARQ-ACK, for the first PDSCH; receiving, from the base station, second DCI scheduling a second PDSCH on the serving cell, the second DCI including second information on a slot offset between the second PDSCH and a second HARQ-ACK for the second PDSCH, wherein a slot for receiving the second PDSCH is after a slot for receiving the first PDSCH; identifying a first slot for the first HARQ-ACK based on the first information and a second slot for the second HARQ-ACK based on the second information; receiving, from the base station, the first PDSCH on the serving cell based on the first DCI; and receiving, from the base station, the second PDSCH on the serving cell based on the second DCI, in case that the second slot for the second HARQ-ACK is same as or after the first slot for the first HARQ-ACK, wherein, the second PDSCH is not received from the base station, in case that the second slot for the second HARQ-ACK is before the first slot for the first HARQ-ACK.