Uplink Power Control with Grouped Pathloss References
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Solution Overview
Problem
Existing LTE technologies face challenges in efficiently managing uplink power control and pathloss reference configuration for carrier aggregation, particularly with multiple licensed and unlicensed bands, leading to increased PUCCH load on the primary cell and suboptimal power consumption.
Innovation Solution
Implementing flexible pathloss reference configurations by grouping cells into PUCCH groups and timing advance groups, allowing for separate pathloss references within each group, and optimizing uplink power control through explicit configuration of pathloss references using RRC messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pathloss reference is used for all cells in carrier aggregation, then the configuration is simple, but the uplink power control accuracy deteriorates for cells in different frequency bands
Solution Approach 1:
The patent divides the set of serving cells into multiple pathloss reference groups, where each group is associated with a specific pathloss reference signal. This segmentation allows different frequency bands to have their own dedicated pathloss references, improving power control accuracy while managing complexity through structured organization of the groups.
Solution Approach 2:
The patent applies local quality by assigning specific pathloss reference signals to specific pathloss reference groups based on the frequency bands of the cells. Each group receives the pathloss reference most appropriate for its frequency characteristics, enabling optimized power control for each local group rather than a uniform approach.
2Measurement precision
If separate pathloss references are configured for each cell group, then uplink power control accuracy is improved, but the signaling overhead increases
Solution Approach 1:
The patent makes the pathloss reference configuration universal by allowing a single pathloss reference signal to serve multiple pathloss reference groups that share similar frequency characteristics. This multi-functionality reduces the total number of references needed while maintaining accuracy for cells with comparable propagation conditions.
Solution Approach 2:
The patent merges multiple pathloss reference configurations into unified groups where cells with similar frequency band characteristics share common pathloss references. This combining approach reduces signaling overhead by eliminating redundant references while preserving the accuracy benefits of differentiated power control.
3Device complexity
If the primary cell handles all PUCCH transmissions for carrier aggregation, then the network structure remains simple, but the PUCCH load on the primary cell increases excessively
Solution Approach 1:
The patent segments the PUCCH transmission responsibilities by introducing secondary PUCCH cells that can independently handle uplink control signals for specific cell groups. This segmentation distributes the PUCCH load away from the primary cell while maintaining a relatively simple overall network structure through the introduction of coordinated secondary references.
Solution Approach 2:
The patent introduces secondary PUCCH cells as intermediary elements that mediate the uplink control signal transmission for secondary cells. These intermediaries absorb the PUCCH load that would otherwise accumulate on the primary cell, enabling better load distribution while the primary cell continues to manage overall coordination.
4Use of energy by moving object
If uplink power control is optimized for each frequency band, then power efficiency is improved, but the configuration complexity increases
Solution Approach 1:
The patent applies local quality by configuring pathloss reference signals specifically tailored to the frequency band characteristics of each cell group. This enables optimized power control for each frequency band (e.g., licensed and unlicensed bands) while organizing the complexity into structured groups that share common reference configurations.
Data Source
AI summary
A base station transmits at least one radio resource control message comprising configuration parameters of a cell, the configuration parameters comprising a cell index identifying the cell and an index identifying downlink subcarriers as a pathloss reference signal of the cell. The base station receives, via uplink subcarriers, at least one uplink signal employing an uplink transmission power. A wireless device receives the at least one radio resource control message. The wireless device determines the uplink transmission power for the at least one uplink signal based on measurements of the downlink subcarriers identified by the index.