Base Station Power Control for Uplink Interference in Mobile Terminals
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Solution Overview
Problem
In a W-CDMA system, terminals experience a rapid increase in transmission power when switching from an active to an inactive state, particularly at higher data transmission rates, necessitating a method to control this increase effectively.
Innovation Solution
A base station measures the signal-to-interference ratio (SIR) and determines whether the terminal is in an active or inactive state based on resource allocation, calculates the average data transmission rate in the active period, and adjusts the target SIR in the inactive period with an offset to prevent rapid power increases, ensuring stable power control and considering interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal switches from active state to inactive state with high data transmission rate, then the transmission power increases rapidly to maintain communication quality, but this causes excessive uplink interference and reduces cell throughput
Solution Approach 1:
The base station predicts the transmission power that would be required in the inactive state based on the data transmission rate from the active state, and proactively adjusts the target SIR before the terminal actually transmits in inactive state. This preliminary adjustment prevents the rapid power increase from occurring in the first place.
Solution Approach 2:
The invention changes the target SIR parameter dynamically based on the data transmission rate. When transitioning from active to inactive state, the target SIR is adjusted using a rate-dependent offset, which modifies the power control target to account for the anticipated power increase, thereby controlling interference without sacrificing communication quality.
2Object-generated harmful factors
If the target SIR is maintained from the previous active period, then the terminal transmission power increases rapidly in inactive state, but if the target SIR is reduced, then the communication quality may deteriorate
Solution Approach 1:
The target SIR parameter is dynamically adjusted based on the data transmission rate. A rate-dependent offset is applied to the target SIR when transitioning to inactive state, where higher data rates result in larger offsets. This selective parameter adjustment reduces interference for high-rate terminals while maintaining appropriate power levels for lower-rate terminals, thus preserving communication quality.
Solution Approach 2:
Different target SIR adjustments are applied to different terminals based on their individual data transmission rates. Each terminal receives a customized target SIR modification tailored to its specific transmission characteristics, rather than a uniform adjustment across all terminals. This localized approach ensures that communication quality is maintained for each terminal while controlling overall interference.
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
In order to solve a problem in which when a terminal is converted from an active state of transmitting data to an inactive state, the transmission power of the terminal rapidly increases, a base station can control the transmission power by predicting and reflecting, in a target SIR, a decrease in SIR which results from an increase in interference amount due to data transmission of another terminal. The present invention can ensure the quality of an uplink control channel by controlling power in consideration of the effect of interference, even when the terminal is in an inactive state.