Adaptive Uplink Power Control for FDMA Interference
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Solution Overview
Problem
Existing Single Carrier and Multi-Carrier Frequency Division Multiple Access (FDMA) communication systems face challenges in achieving a balance between cell-edge performance and overall spectral efficiency, particularly due to interference issues at the edge of cells and low spectral efficiency from traditional power control schemes.
Innovation Solution
The system employs an adaptive power control method where Node B measures and shares system performance metrics with neighboring Node Bs to determine an adaptive power control parameter, which is used to set uplink transmit power levels for user equipment, and implements intra-site interference cancellation by assigning similar channel condition-based resources and decoding signals to mitigate interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If each UE transmits at full power on the uplink, then the received power at the radio access network is maximized, but the cell-edge performance deteriorates due to interference from other sectors/cells
Solution Approach 1:
The patent applies local quality by allowing different UEs to transmit at different power levels based on their specific locations and channel conditions. UEs at cell edges transmit at reduced power while UEs in favorable positions can transmit at higher power, optimizing the trade-off between received power and interference for each local situation.
Solution Approach 2:
The patent implements dynamic power control where the uplink transmit power is continuously adjusted based on real-time system performance metrics, channel conditions, and interference levels. This dynamic adjustment allows the system to adapt to changing conditions and optimize performance across different scenarios.
2Object-affected harmful factors
If traditional power control scheme is implemented where each UE transmits at power resulting in same received power, then interference is reduced, but overall spectral efficiency decreases due to lack of UEs transmitting at high data rates
Solution Approach 1:
The patent changes the power control parameter from a fixed equal-received-power target to an adaptive parameter based on system performance metrics. This allows the received power target to vary dynamically, enabling some UEs to transmit at higher powers when system conditions permit, thereby improving spectral efficiency while maintaining acceptable interference levels.
Solution Approach 2:
The patent implements a feedback mechanism where system performance metrics are measured, reported to the radio access network, and used to adjust power control parameters. This closed-loop feedback enables the system to respond to changing conditions and optimize the balance between interference control and spectral efficiency.
3Productivity
If frequency reuse factor of one is used to maximize spectral efficiency, then data transmission capacity is improved, but interference from other sectors/cells increases especially at cell edges
Solution Approach 1:
The patent changes the power control parameters adaptively based on system performance metrics to compensate for the interference caused by frequency reuse factor of one. By dynamically adjusting power levels, the system can maintain high spectral efficiency while mitigating the adverse effects of increased interference through intelligent power management.
Data Source
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AI summary
A communication system (100) optimizes cell edge performance and spectral efficiency by determining an adaptive power control parameter based on system performance metrics measured by a serving Node B (111) and further measured, and reported to the serving Node B, by neighboring Node B's (110, 112). The adaptive power control parameter is then used to determine an uplink transmit power of a user equipment (UE) (101-104) served by the serving Node B. The uplink transmit power may be determined by the Node B and then conveyed to the UE, or the Node B may broadcast the adaptive power control parameter to the UE and the UE may self-determine the uplink transmit power. In addition, as a frequency reuse factor of one has been proposed for such communication systems, interference levels may be further improved by employment of an intra-site interference cancellation scheme in the sectors serviced by the Node B.