Digital Repeater Subband Isolation for Lower Noise

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Solution Overview

Problem

Existing repeater systems process the full spectrum of a frequency band, including subbands with no useful information, leading to performance degradation and increased noise.

Innovation Solution

A digital repeater system that isolates and processes subbands, determines power estimates for each subband, and mutes those below a threshold to improve system performance by reducing noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the full spectrum of a frequency band is processed in a repeater system, then the system can serve all communication channels, but noise performance degrades and overall noise increases due to processing of subbands without useful information

Engineering Contradiction:
Improvefrequency band coverageVSAvoidnoise
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The frequency band is divided into multiple subbands, each associated with a specific communication channel. The system processes each subband independently by determining power estimates for individual subbands and selectively muting only those subbands that contain no useful information, rather than processing the entire frequency band uniformly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different processing actions are applied to different subbands based on their individual characteristics. Subbands with useful information are processed and transmitted, while subbands without useful information are muted. This local differentiation optimizes noise performance without sacrificing overall frequency band coverage.

Inventive Principle:
Principle #3Local quality

2Productivity

If all subbands are processed and retransmitted, then complete frequency band utilization is achieved, but system performance degrades due to processing and transporting noise in subbands without useful information

Engineering Contradiction:
Improvefrequency band utilizationVSAvoidsystem performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

Before retransmitting the frequency band, the system performs preliminary analysis by determining power estimates for each subband. This preliminary action identifies which subbands contain useful information and which contain only noise, allowing selective muting to be applied before the noise can degrade system performance.

Inventive Principle:
Principle #10Preliminary action

3Object-affected harmful factors

If subband isolation and selective muting are implemented, then noise is reduced and system performance improves, but device complexity increases due to additional processing requirements

Engineering Contradiction:
Improvenoise reductionVSAvoidprocessing complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system extracts only the subbands that contain useful information from the full frequency band, muting and removing subbands that contain only noise. This extraction approach reduces noise impact without requiring complex processing of the entire frequency band, as only relevant subbands are maintained in the signal path.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3823185B1Digital repeater system
Publication Date: 2025.09.24 OUTDOOR WIRELESS NETWORKS LLC
  • EP3823185B1 patent drawingFigure 1~2
  • EP3823185B1 patent drawingFigure 3
  • EP3823185B1 patent drawingFigure 4~5

AI summary

A digital repeater system (1) for repeating RF signals comprises: a receiving section (10) for receiving an RF input signal (RFIN), the RF input signal (RFIN) comprising at least one frequency band (B) including a multiplicity of subbands (S1-S6) associated with a multiplicity of communication channels; and at least one transmitting section (11) for transmitting the RF output signal (RFOUT). The receiving section (10) is constituted to digitize the RF input signal (RFIN) to obtain a digital input signal (IFIN) and to isolate, within the digital input signal (IFIN), the multiplicity of subbands from each other to obtain a multiplicity of digital subband signals (I, Q). The at least one transmitting section (11) is constituted to combine the digital subband signals (I, Q) to obtain a digital output signal (IFOUT) and to convert the digital output signal (IFOUT) to an RF output signal (RFOUT). IN addition, the receiving section (10) comprises a power profile estimation unit (306) for determining a power estimate for each digital subband signal (I, Q) associated with the multiplicity of subbands (S1-S6) and a muting device (307) for muting a digital subband signal (I, Q) of a particular subband (S1-S6) based on the power estimate. In this way a digital repeater system for repeating RF signals is provided which allows for a detection of unused portions of a frequency band in order to improve the performance of the overall system.