Femto Base Station Uplink Power Control for Macrocell Interference
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Solution Overview
Problem
Femto base stations within macrocells face communication quality deterioration due to interference from macrocells, and excessive interference is caused to macrocells from femtocells when target received total wideband power (RTWP) is set in a fixed manner, affecting data transmission rates and overall communication quality.
Innovation Solution
A radio communication system where the target received power for uplink data is dynamically set based on the reception quality of a pilot signal from a macro base station, allowing femto base stations to adjust transmission power to maintain optimal communication quality and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the target RTWP is set to a value substantially equal to that of the macro base station, then the communication quality on the uplink of femto base stations is maintained, but the interference from femto base stations to the macro base station becomes excessive
Solution Approach 1:
The patent applies local quality by setting different target RTWP values for different femto base stations based on their specific locations within the macrocell. Femto base stations closer to the macro base station use lower target RTWP values, while those farther away use higher values, optimizing both communication quality and interference reduction locally for each femto base station
Solution Approach 2:
The patent implements feedback by having the femto base station measure the received power of the macro base station's downlink signal and use this measurement to dynamically adjust its uplink target RTWP value. This closed-loop feedback mechanism ensures that the target RTWP adapts to the actual interference conditions and location within the macrocell
2Object-generated harmful factors
If the target RTWP is increased to reduce interference to the macro base station, then the interference is reduced, but the communication quality on the uplink of the femto base station deteriorates
Solution Approach 1:
The patent applies local quality by setting different target RTWP values for different femto base stations based on their specific locations within the macrocell. Femto base stations closer to the macro base station use lower target RTWP values, while those farther away use higher values, optimizing both communication quality and interference reduction locally for each femto base station
Solution Approach 2:
The patent implements feedback by having the femto base station measure the received power of the macro base station's downlink signal and use this measurement to dynamically adjust its uplink target RTWP value. This closed-loop feedback mechanism ensures that the target RTWP adapts to the actual interference conditions and location within the macrocell
3Device complexity
If the target RTWP is set in a fixed manner, then the configuration is simple, but the data transmission rate cannot be maximized for femto base stations at different locations
Solution Approach 1:
The patent applies dynamics by making the target RTWP value variable rather than fixed. The femto base station dynamically adjusts its target RTWP based on real-time measurements of the macro base station's downlink signal strength, allowing the system to adapt to changing conditions and maximize data transmission rates for femto base stations at different locations
Solution Approach 2:
The patent implements self-service by enabling the femto base station to autonomously determine and adjust its own target RTWP value based on its location and measured signal conditions. This eliminates the need for complex centralized configuration while optimizing performance automatically
Data Source
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AI summary
To provide appropriate communication quality between a radio station (e.g., small-scale base station) and a mobile station in a state where the radio station is located within a large-scale cell and communicates with the mobile station while reducing interference exerted on the large-scale cell by communication between the radio station and the mobile station regardless of the place of the radio station within the large-scale cell. A femto base station 4 sets a target received power RTWP_target of uplink data used for controlling transmission power of uplink data transmission from a mobile station on an uplink based on a measurement result of received power Pmacro of a pilot signal transmitted from a macro base station 3. Specifically, the target received power RTWP_target is preferably set to a larger value as the received power Pmacro of the pilot signal becomes smaller.