UMTS Transmit Power Control Using CM/PAR Estimation
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Solution Overview
Problem
In UMTS wireless transmit receive units, determining the Cubic Metric (CM) or Peak-to-Average Ratio (PAR) before signal transmission is challenging due to the large number of possible signal combinations, making real-time measurement or lookup impractical, especially in handheld devices with memory and latency constraints.
Innovation Solution
A method and apparatus for estimating CM or PAR using predefined configuration cases and preconfigured adjustment factors, allowing for the computation of Maximum Power Reduction (MPR) and setting transmit power without direct measurement, applicable to any multicode signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct measurement or lookup of CM or PAR is performed before signal transmission, then measurement precision is improved, but device complexity and latency increase making it impractical for handheld devices
Solution Approach 1:
The patent segments the continuous problem of CM/PAR measurement into discrete configuration cases. By dividing the signal space into predefined categories (segmentation), the system can use simplified lookup tables for each case rather than performing exhaustive measurements, thereby reducing memory and processing requirements while maintaining adequate measurement precision.
Solution Approach 2:
The patent performs preliminary classification of signals into configuration cases before transmission. By pre-categorizing signals and pre-computing CM/PAR values for each configuration case (preliminary action), the system avoids the need for complex real-time measurements during operation, reducing both device complexity and latency.
2Measurement precision
If the number of configuration cases is increased to improve estimation accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent applies partial action by selecting a representative subset of configuration cases rather than exhaustively covering all possible signal combinations. This partial coverage provides sufficient estimation accuracy for practical purposes while keeping the number of configuration cases manageable, thus balancing measurement precision with device complexity.
3Ease of operation
If preconfigured adjustment factors are used for all configuration cases, then ease of operation is improved, but measurement precision deteriorates due to oversimplification
Solution Approach 1:
The patent applies local quality by using configuration-specific adjustment factors tailored to each configuration case rather than a single universal factor. This allows the system to optimize estimation accuracy for each local configuration scenario while maintaining the overall simplicity of the lookup-based approach, thus balancing ease of operation with measurement precision.
Data Source
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AI summary
A method and apparatus are provided for controlling transmit power with an estimated value of cubic metric (CM) and/or peak-to-average ratio (PAR). Preferably, the method is applied in determining a value for Maximum Power Reduction (MPR) for computing maximum MPR or minimum MPR, by estimating CM and/or PAR from signal parameters. The method of estimating CM and/or PAR is applicable to any multicode signal.