Uplink Power Control via Sliding Window Interference Estimation
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Solution Overview
Problem
In OFDMA-based mobile communication systems, existing uplink power control methods are inaccurate due to varying noise and interference levels, leading to power control errors as they rely on average noise interference values from previous frames, which do not accurately represent current frame conditions.
Innovation Solution
A power controlling method and device that estimate noise and interference levels in real-time by averaging signals across a sliding window of frames, including the current frame, to provide accurate power control values to subscriber stations, thereby reducing power control errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If average noise and interference values from previous frames are used for power control, then power control operation can be performed, but power control accuracy deteriorates due to varying NI levels
Solution Approach 1:
The patent performs preliminary noise and interference estimation for multiple future frames in advance, then selects the most appropriate estimated value for power control. By pre-calculating NI values for multiple frames and selecting based on actual traffic conditions, the system achieves more accurate power control than using only previous frame averages.
Solution Approach 2:
The patent dynamically adapts the power control parameter selection based on actual traffic conditions. Instead of using a fixed previous frame average, the system evaluates multiple estimated NI values and selects the most appropriate one according to current traffic patterns, making the power control adaptive rather than static.
2Adaptability or versatility
If noise and interference estimation is performed for each frame, then power control can adapt to traffic variations, but computational complexity increases
Solution Approach 1:
The patent performs noise and interference estimation for multiple frames (excessive action) but only uses the most relevant estimation for actual power control. By estimating NI for multiple future frames in advance and then selecting only the most appropriate one based on traffic conditions, the system achieves adaptability while managing computational load through selective usage.
3Reliability
If average NI from previous frames is used, then power control can be implemented, but Other-Cell Interference increases due to inaccurate power control
Solution Approach 1:
The patent performs preliminary estimation of noise and interference for multiple future frames, then selects the most appropriate estimated value based on actual traffic conditions. This advance preparation allows for more accurate power control decisions, which in turn reduces unnecessary transmission power and consequently lowers Other-Cell Interference compared to using simple previous frame averages.
Data Source
AI summary
A power controlling device in a mobile communication system, and a method thereof. A base station calculates an average interference of N previous frames, and broadcasts the average interference to subscriber stations. The subscriber stations determine transmission power based on the average interference. Noise and Interference (NI) of frames within a section corresponding to a setting size is calculated (the frames may include a current frame) so an estimated interference is close to the interference generated in the frame in which the subscriber station actually transmits a signal. In addition, to more precisely estimate the NI, the NI of the current frame is compensated according to a value and is broadcast.