Uplink Control Channel Power Determination in TDD Carrier Aggregation
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Solution Overview
Problem
In wireless communication systems, determining the optimal transmit power for an uplink control channel is challenging when multiple cells with different uplink-downlink (UL-DL) configurations are aggregated, as existing methods assume a uniform UL-DL configuration, leading to inefficiencies in ACK/NACK transmission.
Innovation Solution
A method and apparatus that choose the larger value between the number of downlink subframes of two cells with different UL-DL configurations to determine the transmit power for the uplink control channel, ensuring accurate power allocation for ACK/NACK transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If carriers with different UL-DL configurations are aggregated in TDD, then system adaptability and resource utilization are improved, but transmit power determination accuracy deteriorates due to varying M values
Solution Approach 1:
The patent applies local quality by determining transmit power separately for each cell based on its specific UL-DL configuration. Instead of using a uniform power determination method across all aggregated carriers, the system calculates power allocation individually for each cell considering its unique M value (number of downlink subframes), thereby maintaining accuracy while supporting configuration diversity
Solution Approach 2:
The patent changes the parameter M (number of downlink subframes) from a fixed assumption to a dynamic value that varies per cell and per subframe. By adapting the transmit power calculation to reflect the actual M value of each cell's UL-DL configuration, the system achieves accurate power determination across heterogeneous carrier aggregations
2Ease of operation
If a uniform UL-DL configuration is assumed for all aggregated carriers, then power control simplicity is maintained, but power allocation efficiency deteriorates when carriers have different configurations
Solution Approach 1:
The patent segments the power control process by cell and subframe, dividing the aggregated carrier system into independent power determination units. Each cell's transmit power is calculated separately based on its own UL-DL configuration and M value, enabling efficient resource allocation while maintaining manageable complexity through modular calculation
3Adaptability or versatility
If the number of downlink subframes M varies across aggregated carriers, then carrier flexibility is improved, but ACK/NACK transmission reliability deteriorates without proper power adjustment
Solution Approach 1:
The patent introduces dynamics into the power control system by making transmit power adaptive to the actual M value of each cell. The power allocation dynamically adjusts according to the number of downlink subframes in each cell's UL-DL configuration, ensuring that ACK/NACK transmissions maintain sufficient power levels regardless of configuration variations, thereby preserving reliability across flexible carrier aggregations
Data Source
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AI summary
Disclosed are a method for determining the transmission power of an uplink control channel of a terminal which has been assigned, by a base station, two cells that have different UL-DL configurations, and an apparatus using the method. The method comprises: choosing a larger value between N1, the number of downlink subframes that correspond to subframe n of a first cell having a first UL-DL configuration, and N2, the number of downlink subframes that correspond to subframe n of a second cell having a second UL-DL configuration; and determining a parameter value based on the chosen value, wherein the parameter determines the transmission power of an uplink control channel which is transmitted in subframe n.