Multi-Carrier Cubic Metric Weighting for PA Distortion Control
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Solution Overview
Problem
Current wireless communication systems, such as HSPA and LTE, face challenges in accurately computing the cubic metric for power amplifiers when dealing with multiple carriers, as the beta-values used for single-carrier systems are not commensurate across different carriers, leading to distortion issues.
Innovation Solution
The RF-IC adjusts the beta-values before computing the cubic metric by applying weighting factors based on the relative power or amplitude differences between carriers, allowing the cubic metric to be calculated as a function of the adjusted beta-values and power targets, ensuring accurate assessment of non-linearity distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If beta-values are used directly for cubic metric computation in multi-carrier systems, then the computation process is simple, but the accuracy of cubic metric computation deteriorates due to non-commensurability across carriers
Solution Approach 1:
The patent transforms the beta-values by applying weighting factors that account for relative power differences between carriers. This parameter transformation makes the beta-values commensurate across carriers, enabling accurate cubic metric computation while maintaining computational feasibility through a systematic adjustment approach.
Solution Approach 2:
The patent introduces weighting factors as intermediary elements between the original beta-values and the cubic metric computation. These weighting factors serve as mediators that harmonize the power differences across carriers, allowing the cubic metric to be accurately computed from adjusted beta-values without direct complex multi-carrier interactions.
2Reliability
If power levels are increased to improve signal quality in poor environment conditions, then communication reliability improves, but non-linearity distortion in power amplifiers worsens
Solution Approach 1:
The patent computes the cubic metric to provide feedback information about the non-linearity distortion characteristics of the power amplifier. This feedback enables the system to adjust power allocation and modulation strategies to operate within the linear region of the power amplifier, maintaining communication reliability while minimizing distortion.
Solution Approach 2:
The patent performs cubic metric computation and power level optimization in advance before actual transmission. By preliminarily determining appropriate power levels and beta-value adjustments, the system prevents non-linearity distortion from occurring during transmission, rather than attempting to correct it afterward.
Data Source
AI summary
In accordance with an example embodiment of the present invention, a method is disclosed that comprises receiving at least two sets of gain values, wherein each set of gain values denotes the gains of a set of code channels that are carried by each of at least two carriers; receiving at least two power or amplitude levels that are allocated to the at least two carriers; and calculating a cubic metric based on the received at least two sets of gain values and the received at least two power or amplitude levels.