Transmit Path Calibration Using Payload Signal Feedback

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Solution Overview

Problem

Current radio systems for mobile communications networks face challenges in calibrating transmit paths to achieve defined phase and amplitude relationships for beam forming, leading to poor signal-to-noise ratios when using hidden calibration signals, and require extensive hardware for calibration, increasing costs and power consumption.

Innovation Solution

A radio system that splits payload signals into calibrated signals, applies phase and amplitude changes, and updates these changes based on feedback signals, eliminating the need for a dedicated calibration signal generator and reducing hardware requirements by using correlations between payload and baseband feedback signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a dedicated calibration signal is used during idle times, then calibration of transmit paths can be performed, but signal-to-noise ratio deteriorates and interference with other radio systems occurs

Engineering Contradiction:
Improvecalibration accuracyVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent combines the calibration signal with the payload signal by modulating the calibration information onto the payload signal carrier. This merging approach allows calibration to occur during active transmission without creating separate interference-prone calibration transmissions, thereby maintaining signal-to-noise ratio while enabling accurate calibration through correlation processing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The payload signal serves dual functions: carrying actual data traffic and embedded calibration information. By making the payload signal multi-functional, the system eliminates the need for dedicated calibration signals during idle times, avoiding interference with other radio systems while maintaining calibration capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Object-affected harmful factors

If calibration signal is hidden within payload signal, then interference with other signals is reduced, but signal-to-noise ratio becomes very poor

Engineering Contradiction:
Improveinterference with other signalsVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The system employs feedback mechanisms where the receiver processes the combined payload and calibration signal, extracts calibration information through correlation, and feeds back correction data to the transmitter. This feedback loop enables accurate calibration despite the embedded calibration signal being hidden within the payload, maintaining measurement precision without creating interference.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If extensive hardware components are used for calibration, then calibration functionality is achieved, but hardware costs and real estate requirements increase

Engineering Contradiction:
Improvecalibration functionalityVSAvoidhardware components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The radio system performs calibration using its own payload signal without requiring external dedicated calibration equipment. The system extracts calibration information from the transmitted payload signal itself, processes it through correlation at the receiver, and applies corrections autonomously. This self-service approach eliminates the need for separate calibration hardware components, reducing device complexity and real estate requirements while maintaining calibration functionality.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2415187A2A radio system and a method for relaying radio signals
Publication Date: 2012.02.08 KATHREIN SE

AI summary

The present invention provides a radio system (1) and a method (800) for relaying radio signals. The radio system (1) and the method (800) provide a calibration of transmit radio signals in which no dedicated calibration signal generator is required for calibrating the radio system (1). The radio system (1) comprises at least one transmit path, a calibration unit (200) at the least one link (15-1, 15-2,...,15-N). A coupled transmit signal is (90-1, 90- 2,..., 90-N) is extracted from the transmit paths (70-1, 70-2,..., 70-N) and selectively forwarded as a feedback signal (90F) to a feedback signal demodulator (410). The feedback signal demodulator (410) generates a base band feedback signal (90B) adapted for updating phase and amplitude changes (210-1, 210-2,..., 210-N) applied a calibrated payload signal (18-1, 18-2,..., 18-N).