Uplink Power Control in Aggregated Spectrum Systems
Solution Overview
Problem
In wireless communication systems, especially in LTE-A, accurate uplink power control is challenging due to varying channel conditions across different carriers in spectrum aggregation, leading to compromised system performance in terms of capacity, spectral efficiency, and interference mitigation.
Innovation Solution
Implementing a method for wireless communication terminals to independently set and adjust the power levels of uplink carriers based on instructions from a base station, using both open-loop and closed-loop processes to match specific channel conditions, thereby optimizing power control for each carrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate power control is applied to each carrier in spectrum aggregation, then uplink power control accuracy is improved and system performance is enhanced, but device complexity and control overhead increase
Solution Approach 1:
The patent divides the power control mechanism into separate independent control loops for each carrier in the spectrum aggregation. Each carrier receives individual power control commands from the base station, allowing precise adjustment of transmit power per carrier based on its specific channel conditions, thereby resolving the contradiction between power control accuracy and system complexity by making the control granular rather than holistic
Solution Approach 2:
The patent implements dynamic power adjustment where the transmit power of each carrier can be independently modified in real-time based on changing channel conditions. The base station sends separate power control commands for each carrier, enabling the system to adapt dynamically to varying spectral efficiency and interference conditions across different carriers without requiring complete reconfiguration of the entire aggregation
2Productivity
If power levels are independently adjusted for each carrier, then spectral efficiency and capacity are improved, but interference mitigation becomes more challenging due to increased control overhead
Solution Approach 1:
The patent employs feedback mechanisms where the base station monitors the uplink signals from each carrier and sends back power control commands to adjust transmit power levels. This closed-loop feedback allows the system to maintain optimal spectral efficiency by adapting power levels to current channel conditions while simultaneously mitigating interference through coordinated power adjustments across aggregated carriers
Solution Approach 2:
The patent applies different power control strategies and parameters to different carriers based on their local conditions. Each carrier can have its own power adjustment characteristics, allowing the system to optimize spectral efficiency in favorable conditions while aggressively suppressing interference in problematic carriers, thereby resolving the contradiction between productivity and harmful factors through localized optimization
Data Source
AI summary
A method for communication includes modulating data in a wireless communication terminal to produce an aggregated-spectrum signal, which includes multiple component carriers in multiple respective spectral bands, each component carrier including a respective plurality of sub-carriers in respective frequency bins, wherein the component carriers are grouped in one or more groups. The modulated data in transmitted on the multiple component carriers at respective power levels. A single instruction, to set a power level of the component carriers in a given group, is received at the wireless communication terminal. The power level of the component carriers in the given group is set based on the single instruction, and while preserving relative power ratios among the sub-carriers within each of the component carriers.