Uplink Power Control via Pathloss-Based Parameter Selection
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Solution Overview
Problem
Current power control methods in radio communications networks, particularly in OFDM-based systems like LTE and WiMAX, fail to optimize transmission power for user equipment, leading to suboptimal performance in terms of capacity and coverage due to the use of generic α and P0 values that do not account for individual user equipment pathloss conditions, resulting in inefficient interference management and reduced throughput.
Innovation Solution
A method where the radio base station and user equipment dynamically select values for α and P0 based on the pathloss to both the serving cell and interfered cells, allowing for personalized power control that adjusts transmission power to optimize performance for each user equipment, thereby improving both cell-edge and average cell throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full pathloss compensation (α=1) is used to improve cell edge performance, then user equipment at cell edge can transmit with higher power to overcome pathloss, but inter-cell interference increases significantly leading to decreased average cell throughput
Solution Approach 1:
The patent applies local quality by differentiating power control parameters between cell edge user equipment and other user equipment. Specifically, it identifies user equipment based on their pathloss characteristics and applies different α values: cell edge user equipment with higher pathloss receives α=1 for full compensation, while other user equipment receives α<1 to limit interference. This localized differentiation resolves the contradiction by optimizing performance for each spatial region independently.
Solution Approach 2:
The patent dynamically changes the α parameter based on user equipment conditions and network state. It introduces a threshold-based mechanism where α is adjusted from default values (0.4-0.9) to 1.0 for identified cell edge user equipment when certain conditions are met. This parameter change allows the system to adapt between full compensation and limited compensation modes, resolving the throughput-performance tradeoff.
2Device complexity
If generic α and P0 values are used for all user equipment to simplify power control, then system complexity is reduced, but performance is suboptimal due to inability to account for individual user equipment pathloss conditions
Solution Approach 1:
The patent segments user equipment into different categories based on their pathloss characteristics and spatial location. It identifies cell edge user equipment with high pathloss separately from other user equipment, and applies different power control strategies to each segment. This segmentation enables the system to achieve near-optimal performance for each group without requiring fully individualized complex control for every user equipment.
Solution Approach 2:
The patent introduces dynamic adjustment of power control parameters based on changing network conditions and user equipment states. The α parameter and P0 values are not fixed but can be adjusted based on pathloss measurements, interference conditions, and user equipment identification. This dynamics allows the system to adapt to varying conditions while maintaining manageable complexity through structured adjustment rules.
Data Source
AI summary
Embodiments herein relate to a user equipment (10), a radio base station (12) and methods therein for handling transmission power control of the user equipment (10). The user equipment (10) is served by the radio base station (12) in a serving cell (i) controlled by the radio base station (12). The radio base station (12) or user equipment obtains a first pathloss from the user equipment (10) towards the serving cell (i) and a second pathloss from the user equipment (10) towards an interfered cell (j). The radio base station (12) or the user equipment (10) then selects a value of one or more parameters, respectively, which one or more parameters are to be used to control a transmission power of the user equipment (10) and which value is selected based on the first pathloss and the second pathloss.