CPRI Signal Transmission Over Coaxial Lines

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Solution Overview

Problem

Transmitting CPRI signals over coaxial lines occupies high bandwidth, leading to low frequency resource utilization, which is inefficient and costly for base station capacity expansion.

Innovation Solution

Converting CPRI signals into parallel data streams, extracting valid data, and modulating them into analog signals for transmission over coaxial lines, reducing bandwidth requirements and improving frequency resource utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If CPRI signals are transmitted directly over coaxial lines using optical-to-electrical conversion, then transmission capability is achieved, but bandwidth occupation is extremely high and frequency resource utilization is low

Engineering Contradiction:
Improvetransmission capabilityVSAvoidbandwidth occupation
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent segments the CPRI signal transmission process into multiple stages: optical signal reception, electrical conversion, bandwidth compression through selective signal processing, and retransmission. This segmentation allows the system to maintain transmission capability while reducing the bandwidth occupation by processing and optimizing the signal at intermediate stages rather than transmitting the full-width signal directly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies parameter changes by converting the signal from optical domain to electrical domain, then applying frequency domain transformations and bandwidth compression techniques. This changes the fundamental parameters of the signal (frequency, amplitude distribution, bandwidth) to achieve efficient transmission over coaxial lines with reduced bandwidth occupation while maintaining transmission reliability.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If original coaxial lines are used to transmit CPRI signals without reconstruction, then engineering costs are reduced, but frequency resource utilization remains low

Engineering Contradiction:
Improveengineering costVSAvoidfrequency resource utilization
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The patent enables the existing coaxial infrastructure to serve a new function (CPRI signal transmission) by applying signal processing techniques at the transmission endpoints. The coaxial line itself requires no modification and continues to serve its original purpose while simultaneously carrying compressed CPRI signals, making the system self-sufficient and eliminating the need for additional infrastructure investment.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent makes the coaxial line multi-functional by enabling it to simultaneously carry power supply signals and compressed CPRI data signals. This universal approach allows the existing infrastructure to handle multiple tasks (power delivery and data transmission) without requiring separate dedicated lines, thereby reducing engineering costs while improving frequency resource utilization through efficient signal compression.

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

3Measurement precision

If full bandwidth is allocated for CPRI signal transmission, then signal quality is maintained, but frequency resource utilization is inefficient

Engineering Contradiction:
Improvesignal qualityVSAvoidfrequency resource utilization
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential and valid components of the CPRI signal for transmission over the coaxial line. By performing frame parsing, validity judgment, and selective signal extraction, the system removes redundant information and transmits only the critical data elements. This extraction process maintains signal quality for the essential information while significantly reducing the bandwidth required, thereby improving frequency resource utilization.

Inventive Principle:
Principle #2Taking out (Extraction)

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

The method efficiently transmits CPRI signals with lower bandwidth requirements, enhancing frequency resource utilization and reducing the costs associated with base station capacity expansion.

Implementation Method 1

a direct-current power supply and the electrical signal that is converted from a CPRI optical signal are combined by a bias tee

Methodology Applied
Scientific EffectElectrical signal combination:

Implementation Method 2

the direct-current power supply and an optical signal that is converted from the CPRI electrical signal are separated by the bias tee

Methodology Applied
Scientific EffectSignal separation:

Implementation Method 3

then the direct-current power supply and an optical signal that is converted from the CPRI electrical signal are separated by the bias tee, and the two parts of signals are transmitted to a device on the tower

Methodology Applied
Scientific EffectElectrical signal transmission: Conduction (electrical)

Data Source

PatentEP2600684B1Method and device for transmitting common public radio interface signals via coaxial line
Publication Date: 2015.04.22 HUAWEI TECH CO LTD
  • EP2600684B1 patent drawingFigure 1~2
  • EP2600684B1 patent drawingFigure 3
  • EP2600684B1 patent drawingFigure 4

AI summary

Embodiments of the present invention disclose a method and an apparatus for transmitting a CPRI signal by means of a coaxial line. The method includes: converting a Common Public Radio Interface CPRI signal sent by a sending end into a parallel data stream; extracting valid data from the data stream by performing frame parsing; and converting the valid data into a transmittable analog signal, modulating the analog signal to a specified frequency, and sending it to a receiving end by means of a coaxial line. The present invention applies to transmission of a CPRI signal by means of a coaxial line.