LO Leakage Tuning via Error Power Detection
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Solution Overview
Problem
Existing wireless communication systems face challenges in automatically correcting DC offsets on the fly without disrupting signal transmission, as existing methods require processing power and additional components, and often result in data loss due to the need for training modes and shutdowns.
Innovation Solution
A method and apparatus that injects an ideal RF output signal to reduce the actual RF output signal to the LO leakage signal, down-converts, detects, and removes the power of the resulting signal, allowing for on-the-fly suppression without a training mode or special test tone, using a combination of RF power amplifiers and linearization systems in base stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If training systems are used to minimize LO leakage signal, then LO leakage is reduced, but processing power increases and additional components are required
Solution Approach 1:
The patent implements a feedback loop that continuously monitors the RF output signal and automatically adjusts the DC offset compensation. The system feeds back the detected LO leakage signal to dynamically tune the DC offset correction, eliminating the need for complex training systems while maintaining effective LO leakage suppression through continuous automatic adjustment
Solution Approach 2:
The system performs self-tuning by automatically detecting and compensating for its own LO leakage without requiring external training sequences or additional control components. The DC offset correction is self-adjusting based on the detected leakage signal, making the system self-sufficient and reducing overall device complexity
2Object-generated harmful factors
If training mode is used to tune DC offset, then LO leakage is suppressed, but signal transmission is interrupted causing data loss
Solution Approach 1:
The patent maintains continuous signal transmission while performing DC offset correction. The feedback loop operates concurrently with normal data transmission, allowing the system to continuously suppress LO leakage without interrupting the useful action of signal transmission, thereby preventing any data loss
Solution Approach 2:
The system performs preliminary DC offset correction by continuously preparing compensation signals through the feedback mechanism before any potential interference occurs. This ongoing preliminary adjustment ensures that LO leakage is suppressed in advance while transmission continues uninterrupted
3Device complexity
If direct modulation is used to simplify transmitter, then device complexity is reduced, but DC offset increases
Solution Approach 1:
The patent adds a feedback mechanism that automatically detects and compensates for the DC offset generated by direct modulation. This feedback loop monitors the RF output and dynamically adjusts the DC offset correction, allowing the system to maintain the simplicity of direct modulation while eliminating its harmful DC offset effect through automatic compensation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables high-power RF output with minimal unwanted components, maintaining signal fidelity and reducing carrier leakage, achieving suppression of LO leakage signals by up to 70dB, thus improving signal quality without interrupting transmission.
Implementation Method 1
the power of the down-converted signal detected
Data Source
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AI summary
A communication device (110) and method of removing an LO leakage signal from a signal path on the fly is disclosed. The signal path may be that of a transmitter or receiver. An initial RF output signal, containing a desired RF output signal and an LO leakage signal, is supplied from a feedforward path to a combiner/splitter (508) on a feedback path. A 180° out-of-phase copy of the desired RF output signal is also supplied to the combiner/splitter. The resulting LO leakage signal is down-converted and the power of the down-converted signal determined and used to suppress the LO leakage signal. The resulting LO leakage signal is also supplied to the feedforward path of the feedback loop.