Radio Base Station Power Control with Corrected SIR Target
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Solution Overview
Problem
Conventional SIR-based power control methods in cellular radio systems lead to power peaks and long settling times due to inter-user coupling, and power-based methods fail to guarantee signal quality, resulting in increased interference and block errors.
Innovation Solution
A corrective Signal-to-Interference Ratio (SIR) target term is introduced in the inner power control loop of a radio base station, combining the existing SIR target with a calculated correction term during the grant delay to set new power levels before they are used, thereby avoiding oscillations and power rushes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SIR-based power control is used to guarantee signal quality for each user, then signal quality is maintained, but power peaks and long settling times occur due to inter-user coupling
Solution Approach 1:
The patent applies preliminary action by calculating and applying a correction term to the SIR target before the grant delay expires. The base station computes the correction term based on the difference between old and new grants, and applies it during the remaining grant delay period. This anticipatory adjustment prevents power peaks and oscillations from occurring in the first place, rather than reacting after they occur.
Solution Approach 2:
The patent implements feedback by continuously monitoring the grants received by users and calculating the resulting correction term to the SIR target. The system measures the impact of grant changes on interference levels and adjusts the SIR target accordingly, creating a closed-loop control system that maintains stability while adapting to changing conditions.
2Use of energy by moving object
If power-based control is used to reduce power consumption, then power peaks are reduced, but signal quality cannot be guaranteed leading to increased block errors
Solution Approach 1:
The patent applies parameter changes by modifying the SIR target parameter dynamically based on grant conditions. Instead of using fixed power-based control or fixed SIR targets, the system adjusts the SIR target parameter in real-time according to the difference between old and new grants, optimizing both power efficiency and signal quality simultaneously.
3Reliability
If conventional SIR-based power control is used, then signal quality is maintained, but interference increases due to users repeatedly triggering power level increases
Solution Approach 1:
The patent applies preliminary anti-action by introducing a correction term that counteracts the tendency toward power peaks before they occur. The correction term is calculated to offset the interference that would result from grant changes, preventing the chain reaction of power increases that would otherwise occur among users.
Data Source
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AI summary
In methods and devices for use in a radio base station of a cellular radio system, where the radio base station is arranged to control the power transmitted in the uplink by a user equipment by transmitting power control commands in the downlink to the user equipment striving to keep the received uplink Signal-to-interference Ratio, SIR, at a given SIR target, the power transmitted is controlled by transmitting transmit power control commands in the downlink striving to keep the received uplink Signal-to-interference Ratio, SIR, at a corrected SIR target. The corrected SIR target can be a SIR target supplemented by a corrective term.