Adaptive Open-Loop Power Control in TDD Mobile Systems
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Solution Overview
Problem
Conventional open-loop power control methods in TDD mobile communication systems face challenges such as varying power compensation values due to subscriber movement, measurement errors, antenna path loss considerations, and periodic power compensation renewals, which affect power control accuracy and efficiency.
Innovation Solution
An adaptive open-loop power control method that uses receive power measurements and feedback from frame error information to determine uplink transmit power, incorporating a compensation value that adjusts based on interference and channel conditions, allowing for precise power control and reduced signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional open-loop power control is used with fixed power compensation values, then the control method is simple, but power control accuracy deteriorates due to subscriber movement and channel variations
Solution Approach 1:
The patent applies dynamics by transitioning from fixed power compensation values to adaptive power compensation values that change based on real-time channel conditions. The power compensation value is dynamically adjusted according to downlink reference signal received power measurements and uplink frame error rates, allowing the system to adapt to subscriber movement and channel variations while maintaining accurate power control.
Solution Approach 2:
The patent implements feedback mechanisms by using uplink frame error rate information and downlink reference signal received power measurements to adjust power compensation values. The base station feeds back power control commands to the mobile station based on measured channel conditions, creating a closed-loop system that continuously refines power control accuracy despite the open-loop nature of the basic mechanism.
2Adaptability or versatility
If periodic power compensation renewal is used, then the system can adapt to channel changes, but signaling overhead increases and link stability deteriorates during renewal transitions
Solution Approach 1:
The patent applies periodic action by renewing power compensation values at specific intervals based on downlink reference signal received power measurements. The base station periodically measures the downlink reference signal power and updates the power compensation value accordingly, allowing the system to adapt to gradual channel changes while maintaining stability through structured periodic updates rather than continuous adjustments.
Solution Approach 2:
The system performs self-service by using the mobile station's own received power measurements of downlink reference signals to determine appropriate power compensation values. The mobile station autonomously measures and reports channel conditions, enabling the system to self-adjust power compensation without requiring extensive external signaling or manual intervention, thereby reducing signaling overhead.
3Measurement precision
If power compensation value is adjusted frequently to account for subscriber movement, then power control accuracy improves, but link stability deteriorates due to frequent changes
Solution Approach 1:
The patent applies dynamics by implementing adaptive power compensation that responds to real-time channel conditions while incorporating hysteresis mechanisms. The power compensation value changes dynamically based on measured downlink reference signal power and uplink frame error rates, but the system incorporates minimum change thresholds and hysteresis to prevent excessive frequent adjustments, thereby maintaining link stability while adapting to subscriber movement.
Solution Approach 2:
The patent applies parameter changes by modifying the power compensation value based on multiple parameters including downlink reference signal received power, uplink frame error rate, and minimum power changes. The system changes the power compensation parameter adaptively while incorporating minimum change thresholds and hysteresis parameters to prevent overly frequent adjustments, balancing power control accuracy with link stability.
Data Source
AI summary
Disclosed is an apparatus for determining transmit power of an uplink frame transmitted from a subscriber station to a base station and transmitting data in a mobile communication system in which a downlink frame, transmitted from the base station to the subscriber station, and the uplink frame are time division-duplexed (TDD). The apparatus includes a receive power measurement unit for measuring receive power of signals received from the base station; a transmit power controller for determining the transmit power of the uplink frame from the receive power measured by the receive power measurement unit and information related to receptions of an uplink frame, which is received from the base station; and a transmission radio frequency processor for performing radio processing so that the uplink frame is transmitted according to the transmit power determined by the transmit power controller.