Radio System Feedback Path Calibration and Digital Predistortion
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Solution Overview
Problem
Current radio systems for mobile communications face challenges in efficiently calibrating phase and amplitude changes and digital predistortions for packetized radio signals, leading to potential deterioration of signal quality and increased costs due to the need for multiple feedback paths and complex calibration processes.
Innovation Solution
A radio system that uses correlations between payload and feedback signals to adapt phase and amplitude changes and digital predistortions, utilizing a single feedback path for both calibration and updating, allowing for concurrent base band calibration to maintain signal quality and reduce manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single feedback path is used for both calibration and updating digital predistortion, then device complexity and manufacturing cost are reduced, but it becomes difficult to maintain both signal quality and calibration accuracy simultaneously
Solution Approach 1:
The patent segments the feedback signal processing into distinct functional blocks: a calibration extraction block that separates calibration signals from payload signals, and separate processing paths for calibration and payload signals. This segmentation allows the single feedback path to handle multiple functions without compromising the accuracy of either calibration or normal operation.
Solution Approach 2:
The patent introduces an intermediary calibration signal that is injected into the feedback path to enable calibration operations. This calibration signal acts as a mediator that allows the system to measure and adjust phase and amplitude deviations without interfering with the normal payload signal transmission, thus maintaining both calibration accuracy and signal quality using the same feedback path.
2Manufacturing precision
If multiple feedback paths are used for calibration and updating, then signal quality and calibration accuracy are maintained, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent makes the single feedback path universal by enabling it to perform multiple functions: carrying both calibration signals and payload signals, and supporting both calibration operations and normal transmission operations. The feedback path is designed to handle different signal types and operations sequentially or concurrently through signal separation techniques, eliminating the need for multiple dedicated feedback paths while maintaining all necessary functionality.
Solution Approach 2:
The patent merges the previously separate calibration feedback path and payload feedback path into a single unified feedback path. By combining these functions into one path with appropriate signal separation and processing blocks, the system reduces hardware complexity and manufacturing cost while maintaining the calibration accuracy and signal quality that would otherwise require separate paths.
3Adaptability or versatility
If packetized payload signals undergo multiple buffering and PLL processing steps, then signal processing flexibility is improved, but the defined temporal order of the packetized signal deteriorates or is destroyed
Solution Approach 1:
The patent applies preliminary digital predistortion to the packetized payload signal before it enters the buffering and PLL processing stages. This predistortion compensates for the temporal order deterioration that will occur during subsequent processing, effectively pre-correcting the signal to maintain its integrity despite the flexible processing steps that follow.
Solution Approach 2:
The patent implements a feedback mechanism where the actual output signal is compared with the expected output, and the differences (phase and amplitude deviations) are used to adjust the digital predistortion parameters. This closed-loop feedback ensures that even though multiple buffering and PLL steps may alter the temporal order, the system continuously adapts to maintain the correct signal characteristics and temporal relationships.
Data Source
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AI summary
The present invention provides a radio system (1) and a method (800) for relaying packetized radio signals. The radio system (1) comprises at least one transmit path (70-1, 70-2,..., 70-N), a base band calibration signal generator (220B) for generating a base band calibration signal (222B), a digital predistortion unit (300), a calibration unit (200) and a feedback path (400). The feedback path (400) is commonly used by the digital predistortion unit (300) and the calibration unit (200) for feeding back a feedback signal (90F). The feedback signal (90F) is adapted to update at least one of phase and amplitude changes (210-1, 210-2,..., 210-N) and the digital predistortion (310-1, 310-2,..., 310-N). The present invention further relates to a method (800) for relaying packetized radio signals. The method (800) is capable of updating (870) the digital predistortion (310-1, 310-2,..., 310-N) as well as adapted for an updating (880) of the phase and amplitude changes (210-1, 210-2,..., 210-N). The updating (870) of the digital predistortion (310-1, 310-2,..., 310-N) and the updating (880) of the phase and amplitude changes (210-1, 210-2,..., 210-N) is implemented using the feedback signal (90F). The present invention further relates to a computer program product for the manufacture of the radio system (1). The present invention further relates to a computer program product for the execution of the method (800).