Outer Loop Power Control SIR Convergence
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Solution Overview
Problem
Current outer loop power control in WCDMA systems experiences fast up-regulation and slow down-regulation, leading to inefficient transmission power usage and prolonged convergence times when channel conditions change, especially in scenarios with varying signal quality and limited uplink signals.
Innovation Solution
A method that accelerates the convergence of the Signal to Interference Ratio (SIR) target by using a combination of Block Error Rate (BLER) and Bit Error Rate (BER) measurements, with filtering and adjustable parameters to ensure quality of service, including a filtering unit to process BER values and adjust SIR targets dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the SIRtarget is up-regulated when BLER exceeds the threshold, then the service quality is improved, but the down-regulation of SIRtarget becomes slow causing power waste
Solution Approach 1:
The patent segments the error rate measurement into two distinct components: BLER measurement for up-regulation decisions and BER measurement for down-regulation decisions. This segmentation allows the system to use different measurement metrics and time scales for increasing versus decreasing the SIRtarget, thereby resolving the contradiction between rapid response to quality degradation and slow recovery to prevent power waste.
Solution Approach 2:
The patent implements dynamic adjustment of the SIRtarget based on real-time channel conditions by continuously monitoring both BLER and BER. The system dynamically switches between up-regulation and down-regulation modes based on which threshold is violated, enabling adaptive power control that responds appropriately to changing channel conditions without the fast-up/slow-down phenomenon.
2Reliability
If the measurement time of BLER is extended to ensure accuracy, then the reliability of power control is improved, but the convergence speed of SIRtarget decreases
Solution Approach 1:
The patent divides the power control adjustment process into two parallel tracks: one using BLER measurements for up-regulation and another using BER measurements for down-regulation. This segmentation allows each measurement type to operate with its own optimal time scale, with BER providing rapid down-regulation feedback without requiring extended measurement periods, thus maintaining both reliability and convergence speed.
Solution Approach 2:
The patent performs preliminary BER measurement and evaluation in parallel with BLER measurement. By having the BER data prepared and available in advance, the system can immediately initiate down-regulation when conditions permit, without waiting for extended BLER measurement periods to elapse, thereby accelerating convergence while maintaining control reliability.
3Reliability
If a high initial SIRtarget is configured to maintain call completion rate, then the call completion rate is improved, but the convergence time to normal working point increases causing power waste
Solution Approach 1:
The patent implements dual feedback mechanisms: BLER feedback for maintaining service quality during channel degradation and BER feedback for detecting channel improvement. This dual feedback system allows the high initial SIRtarget to be maintained only as long as necessary for call completion, with BER providing early warning of channel improvement to trigger timely down-regulation, thereby reducing convergence time and power waste.
Solution Approach 2:
The patent makes the SIRtarget dynamically adjustable based on real-time BER and BLER measurements. Rather than maintaining a statically high SIRtarget throughout the call, the system dynamically adapts the SIRlevel by using BER to detect when channel conditions have improved sufficiently to allow down-regulation, thus maintaining call completion rate while minimizing convergence time and power consumption.
Data Source
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AI summary
A method and an apparatus for controlling outer loop power are provided by the present invention. The method comprises the steps as follows: a BLER acquisition unit obtains a BLER of received data by carrying out decoding and a cyclic redundancy check on the data (S101); a bit error rate acquisition unit obtains a BER of a dedicated physical control channel by judging a pilot signal (S102); it is judged that whether or not the BLER of the data is greater than a BLERtarget and a first adjustment on the SIRtarget is carried out according to the judgment result(S 103); and if values of n consecutive BERs are smaller than or equal to a Bit Error Rate target value (BERtarget), then a second adjustment is carried out, wherein n is a positive integer (S 104). A method for accelerating the convergence of SIR is provided by the present invention with the premise of ensuring the quality of services, which not only can ensure the minimum signal to interference ratio required by the services but also can accelerate the convergence speed of the SIR.