Uplink Power Control for Multi-TA Group Wireless Devices
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Solution Overview
Problem
In 3GPP LTE and LTE-A systems, regulating uplink transmit power among multiple serving cells with different time alignment values is challenging due to varying propagation properties, leading to interference and inefficient power management.
Innovation Solution
A method for controlling uplink transmit power by considering overlapping durations between subframes of serving cells belonging to different timing advance groups, allowing for dynamic adjustment of transmit power based on specific TA group configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same time alignment value is applied to all serving cells, then the system configuration is simplified, but interference between uplink transmissions from different serving cells increases due to varying propagation properties
Solution Approach 1:
The patent divides serving cells into different timing advance groups (TAGs) based on their propagation properties. Each TAG is assigned a separate time alignment value, allowing independent timing control for different cell groups. This segmentation resolves the contradiction by maintaining simplified configuration within each group while enabling differentiated timing management across groups to reduce interference.
Solution Approach 2:
The patent applies different time alignment values to different timing advance groups, allowing each group to have optimized timing parameters suited to its specific propagation characteristics. This local differentiation enables precise timing control for each cell group, reducing inter-cell interference while maintaining overall system coherence.
2Reliability
If uplink transmit power is increased to improve signal quality, then reception quality improves, but interference to other uplink transmissions increases significantly
Solution Approach 1:
The patent dynamically adjusts uplink transmit power based on the specific timing advance group configuration and overlapping duration calculations. The power control mechanism adapts to different TAG scenarios, allowing optimized power levels for each cell group while preventing excessive interference. This dynamic adjustment resolves the contradiction by matching power output to actual transmission conditions rather than using fixed high power.
Solution Approach 2:
The patent changes the power control parameters based on timing advance group identifiers and overlapping duration measurements. By incorporating TAG information and duration calculations into the power determination process, the system achieves precise power adjustment for each cell group, improving reception quality while controlling interference through parameter-based optimization.
3Productivity
If multiple serving cells with different time alignment values are configured, then data rate is improved through carrier aggregation, but power management complexity increases
Solution Approach 1:
The patent segments power management by associating specific power control rules with each timing advance group. Instead of uniform power management across all cells, the system applies differentiated power control for each TAG, simplifying the overall management process while supporting multiple serving cells with different timing characteristics for enhanced data rate.
Solution Approach 2:
The patent introduces timing advance group information as an intermediary parameter that mediates between the multiple serving cells and the power control mechanism. By using TAG identifiers and overlapping duration calculations as intermediate calculation steps, the system manages power across multiple cells with different timing values in an organized manner, reducing overall complexity while maintaining high data rate capability.
Data Source
AI summary
The present invention relates to a method for controlling uplink transmission power and to a wireless device using same in a wireless communication system. The wireless device receives determines uplink transmission power in consideration of the overlap period between subframes between a first serving cell belonging to a first timing advance (TA) group and a second serving cell belonging to the second TA group, and transmits an uplink channel on the basis of the uplink transmission power.