Shared Feedback Path for Beamforming Radio Calibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current radio systems for mobile communications require complex and time-consuming calibration processes for beam forming techniques, involving two distinct feedback paths that increase hardware complexity and calibration time, especially due to non-linearities in transfer characteristics caused by amplifiers.
Innovation Solution
A radio system with a single feedback path that uses digital predistortion and phase/amplitude calibration units, where correlations between payload and feedback signals within the same frequency range allow concurrent updating of digital predistortions and phase/amplitude changes, eliminating the need for a calibration signal generator and reducing hardware components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If two distinct feedback paths are used for calibration and digital predistortion, then the radio system can maintain accurate phase and amplitude relationships, but the hardware complexity and calibration time increase
Solution Approach 1:
The patent combines two separate feedback paths into a single shared feedback path that serves both calibration and digital predistortion functions. The feedback signal is tapped from the transmit path and distributed to both the calibration unit and digital predistortion unit, eliminating redundant hardware components while maintaining the ability to independently update phase/amplitude changes and predistortion coefficients
Solution Approach 2:
The single feedback path is designed to serve multiple functions simultaneously - it provides feedback for both calibration operations and digital predistortion operations. The feedback signal contains information about the actual transmit signal characteristics that both units can utilize for their respective correction purposes, making the feedback path universal rather than dedicated to a single function
2Manufacturing precision
If two distinct feedback paths are used for calibration and digital predistortion, then accurate signal correction is achieved, but the calibration process becomes time-consuming
Solution Approach 1:
The patent enables continuous calibration operations by using a single feedback path that continuously provides feedback signals for both calibration and predistortion updates. Instead of sequentially executing separate calibration and predistortion procedures that would require switching between different feedback paths, the system performs both functions concurrently using the same continuous feedback stream, significantly reducing total calibration time
3Power
If amplifiers are used in transmit paths, then signal power is sufficient for transmission, but non-linearities are introduced that distort phase and amplitude relationships
Solution Approach 1:
The patent applies digital predistortion to the transmit signal before it reaches the amplifier stage. The predistortion unit pre-compensates for the expected non-linearities by applying inverse distortion characteristics to the signal. This preliminary action ensures that when the signal passes through the non-linear amplifier, the combined effect (predistortion + amplifier non-linearity) results in a linear overall transfer characteristic, preserving phase and amplitude relationships
Data Source
AI summary
The present invention provides a radio system (1) and a method (800) for relaying radio signals. The radio system (1) comprises at least one transmit path (70-1, 70-2,..., 70-N), 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) with the present invention. The calibration signal (222) 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 radio signals. The method (800) comprises updating (870) the digital predistortion (310-1, 310-2,..., 310-N) as well as 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 a feedback signal (90F). The present invention further relates to a computer program product for the manufacture of the radio system (1) according to the invention. The present invention further relates to a computer program product for the execution of the method (800) according to the present invention.