Microwave Repeater Spectrum Inversion for Signal Quality

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Solution Overview

Problem

Microwave radio links suffer from signal attenuation and imperfections introduced by repeaters, degrading connection performance over long distances, which existing methods fail to adequately address.

Innovation Solution

A microwave radio link chain with repeaters that invert the signal spectrum and amplify signals, ensuring 'self-healing' by mitigating linear frequency-dependent impairments, and optionally performing signal processing to maintain optimal transfer functions across the chain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If repeater stations are used to extend microwave radio link distance, then connection distance is improved, but signal quality deteriorates due to imperfections introduced by repeaters

Engineering Contradiction:

Improveconnection distanceVSAvoidsignal quality

Core Design Contradiction:

Length of stationary objectVSReliability

Solution Approach 1:

The patent applies spectrum inversion at repeater stations, where the frequency spectrum of the signal is inverted (f -> -f) before retransmission. This inversion technique causes linear frequency-dependent impairments to be reversed, effectively canceling out the degradation accumulated from previous repeaters and enabling long-distance transmission while maintaining signal quality

Inventive Principle:

Principle #13The other way round (Inversion)

2Speed

If microwave radio links are used instead of optical fiber, then propagation speed is improved, but signal attenuation worsens over distance

Engineering Contradiction:

Improvepropagation speedVSAvoidsignal attenuation

Core Design Contradiction:

SpeedVSLoss of energy

Solution Approach 1:

The patent converts the harmful effect of signal attenuation into a beneficial outcome by using spectrum inversion at repeaters. The inversion process causes impairments to be reversed, turning the cumulative degradation that would normally occur over long distances into a self-correcting system where signal quality is restored rather than degraded

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Power

If multiple repeaters are used to maintain signal strength, then signal amplification is improved, but cumulative impairments worsen

Engineering Contradiction:

Improvesignal amplificationVSAvoidcumulative impairments

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

By inverting the spectrum at each repeater station, the patent ensures that linear frequency-dependent impairments are reversed rather than accumulated. This means that while multiple repeaters are used to maintain signal strength through amplification, the cumulative impairments are actually canceled out, allowing multiple repeaters to be used without degrading signal quality

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentEP3005582B1Radio link with repeater

Publication Date: 2019.01.16 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

Figure 1a~1b
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AI summary

A microwave radio link chain (200) comprising a first transmitter (205), a first receiver (215) and one or more repeaters (210) between the first transmitter (205) and the first receiver (215). The one or more repeaters (210) is arranged to receive (221) signals originally transmitted by the first transmitter (205) and to transmit (222, 240) the received signals in the direction of the first receiver (215), the microwave radio link chain (200) being characterized in that one or more of said repeaters (210) is arranged to invert (255) the spectrum of the signals before they are transmitted by the repeater. In embodiments, one or more of the repeaters (210) is also arranged to amplify the received signals before they are transmitted.