Uplink Power Control via Interference Feedback
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Solution Overview
Problem
In LTE and LTE-Advanced systems, uplink power control faces challenges in managing interference from users scheduled in neighboring cells, making SINR estimation and modulation and coding scheme selection difficult, and existing methods fail to effectively reduce individual interference and variance.
Innovation Solution
A method that involves measuring downlink pathloss by user equipment to determine uplink transmit power in open loop control and measuring interference power by neighboring eNodeBs to compute average interference and adjust power settings in closed loop control, targeting reduced interference and improved SINR estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If fractional power control is used to control uplink transmission power, then uplink power control is achieved, but interference at neighboring cells becomes highly variable and dependent on scheduled users
Solution Approach 1:
The patent implements a two-stage closed-loop power control mechanism where the eNodeB measures uplink interference on resource blocks, computes average interference power per scheduled user, and sends power adjustment commands back to UEs. This feedback loop continuously adapts transmit power to maintain target interference levels, resolving the variability issue of conventional fractional power control.
Solution Approach 2:
The patent dynamically changes the transmit power parameter based on measured interference conditions. By computing average interference power and comparing it against target interference thresholds, the system adjusts the power parameter adaptively, transforming the static fractional power control into a dynamic control mechanism that stabilizes neighboring cell interference.
2Object-generated harmful factors
If individual user interference to neighboring cells is reduced, then interference management improves, but SINR estimation and MCS selection remain challenging due to user scheduling variability
Solution Approach 1:
The eNodeB measures actual uplink interference on each resource block and uses this measured feedback to compute accurate SINR values. By basing SINR estimation on real measurements rather than theoretical calculations, the system achieves precise SINR values that accurately reflect current interference conditions, enabling reliable MCS selection.
Solution Approach 2:
The patent replaces the conventional SINR estimation method (based on pathloss calculations and fractional power control assumptions) with a measurement-based approach. The eNodeB directly measures interference power on resource blocks, substituting theoretical estimation with empirical measurement to achieve higher accuracy.
3Power
If transmit power is continuously adjusted to maintain target total interference, then system-wide interference control improves, but variance of individual cell interference remains high
Solution Approach 1:
The patent segments the interference control by resource block, measuring and controlling interference on each resource block separately rather than treating total interference as a single aggregate value. This granular segmentation allows precise control of interference distribution across different frequency resources, reducing variance in individual cell interference while maintaining target total interference levels.
Solution Approach 2:
The system dynamically changes transmit power parameters based on real-time interference measurements on each resource block. By adapting power levels to actual measured conditions rather than using fixed fractional adjustments, the system maintains stable interference composition across different scheduling scenarios while achieving target total interference control.
Data Source
AI summary
A method for uplink power control implemented in a wireless communications system including one or more user equipment, a serving base station, and at least one neighboring base station is disclosed. The method comprises measuring, at each user equipment, pathloss, sending, from each user equipment to the serving base station, the pathloss, and determining, at the serving base station, uplink transmit power based on the pathloss. Other methods, systems, and apparatuses also are disclosed.