Frequency Shifting in Multi-Frequency DAS to Reduce Interference
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Solution Overview
Problem
Distributed antenna systems (DASs) face interference issues due to non-linear signal processing components generating out-of-band harmonics, which can lead to frequency band interference, limiting dynamic range and requiring power reduction to mitigate these issues.
Innovation Solution
Implementing a frequency shifting mechanism in DASs to predict and shift communications signals, thereby moving interfering signal products outside the frequency range of other signals, allowing for higher signal-to-noise ratios without power limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If non-linear signal processing components are used in DAS, then signal processing capability is improved, but out-of-band harmonics are generated causing frequency band interference
Solution Approach 1:
The patent predicts harmful harmonic frequencies generated by non-linear components and proactively shifts communication signal frequencies to avoid these harmful frequencies. This converts the potential harm of harmonics into a benefit by using the prediction information to optimize frequency allocation and prevent interference before it occurs.
Solution Approach 2:
The system performs preliminary prediction of harmonic frequencies before actual signal transmission. By calculating and identifying potential interfering frequencies in advance, the system can pre-adjust communication signal frequencies to avoid interference, rather than reacting to interference after it occurs.
2Object-affected harmful factors
If power reduction is applied to mitigate harmonic interference, then frequency band interference is reduced, but dynamic range is limited
Solution Approach 1:
Instead of uniformly reducing power across all signals, the patent dynamically changes frequency parameters of communication signals based on predicted harmonic locations. This allows maintaining optimal power levels and dynamic range while avoiding specific frequency ranges where harmonics would cause interference.
3Object-affected harmful factors
If frequency shifting is implemented to avoid harmonics, then frequency interference is reduced, but system complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors actual signal conditions, compares them with predicted harmonic frequencies, and adjusts communication signal frequencies accordingly. This closed-loop approach ensures interference avoidance while adapting to changing system conditions without requiring overly complex predetermined configurations.
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
This approach effectively reduces frequency interference, enhancing signal quality and maintaining dynamic range by shifting signals to avoid harmonics, thus improving overall system performance.
Implementation Method 1
a first frequency shifting circuit configured to frequency shift the at least one first communications signal from a first frequency to a shifted first communications signal at a shifted first frequency based on a first frequency control signal
Data Source
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AI summary
Frequency shifting a communications signal(s) in a multiple frequency (multi- frequency) distributed antenna system (DAS) to avoid or reduce frequency interference is disclosed. Related devices, methods, and DASs are disclosed. Non-limiting examples of frequency interference include frequency band interference and frequency channel interference. As a non-limiting example, frequency interference in a multi-frequency DAS may result from non-linearity of a signal processing component generating an out-of-band harmonic of a first, in-use communications, signal in a first frequency band, within different frequency band(s) of other in- use communications signal(s). To avoid or reduce such interference, embodiments disclosed herein involve predicting frequency interference that may result from processing received, in-use communications signals in multiple frequency bands to be distributed in a multi-frequency DAS. Frequency shifting is performed to avoid or reduce any interfering signal products produced from the signal processing of any in-use communications signals, from interfering in the frequencies of other in-use communications signals,