BBU-RRU Data Transmission via Direct Electrical Interface

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Solution Overview

Problem

The existing data transmission method between a BBU and an RRU is inefficient due to the need for encapsulating radio signals according to the CPRI protocol, resulting in a high amount of invalid data and the requirement for a large number of optical fibers.

Innovation Solution

The method involves determining a correspondence between an input port and a bearer channel, performing CDMA and carrier modulation on the radio signal, and modulating it to an optical wavelength, eliminating the need for encapsulation and reducing the number of optical fibers required by distinguishing signals using codewords and carriers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If radio signals are encapsulated according to the CPRI protocol for transmission between BBU and RRU, then the transmission can be standardized and compatible, but the amount of invalid data increases and transmission efficiency decreases

Engineering Contradiction:
Improveprotocol compatibilityVSAvoidtransmission efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent extracts and removes the CPRI protocol encapsulation layer from the transmission process. By directly transmitting the baseband signal without wrapping it in CPRI protocol frames, the solution eliminates the overhead and invalid data associated with protocol encapsulation, thereby improving transmission efficiency while maintaining compatibility through direct electrical connection

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a direct electrical connection as an intermediary medium between BBU and RRU, replacing the optical fiber infrastructure. This direct electrical interface allows baseband signals to be transmitted without protocol encapsulation, achieving both high transmission efficiency and simplified architecture

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If CPRI protocol encapsulation is used for BBU-RRU communication, then signal transmission can be achieved, but a large quantity of optical fibers need to be deployed

Engineering Contradiction:
Improvesignal transmissionVSAvoidnumber of optical fibers
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent merges multiple functions into a single direct electrical connection between BBU and RRU. This unified interface simultaneously handles signal transmission, synchronization, and control functions that previously required separate optical fiber connections and protocol encapsulation, thereby reducing the quantity of optical fibers needed

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the mechanical/optical fiber transmission system with an electrical connection system. By substituting optical fibers with direct electrical interfaces, the solution eliminates the need for complex optical infrastructure while maintaining reliable signal transmission between baseband units and radio units

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 improves transmission efficiency by reducing invalid data and the number of optical fibers needed between the BBU and RRU, enhancing the overall system performance.

Implementation Method 1

modulating the modulated electrical signal to an optical wavelength corresponding to the bearer channel, to obtain a modulated optical signal

Methodology Applied
Scientific EffectModulation: Phase Modulation

Data Source

PatentEP3340734B1Data transmission method and apparatus
Publication Date: 2021.11.10 HUAWEI TECH CO LTD
  • EP3340734B1 patent drawingFigure 1
  • EP3340734B1 patent drawingFigure 2a
  • EP3340734B1 patent drawingFigure 2b~3

AI summary

The present invention provides a data transmission method and apparatus. The method includes: obtaining a radio signal by using an input port; determining, according to a correspondence between an input port and a bearer channel, a bearer channel corresponding to the radio signal; performing CDMA modulation and carrier modulation on the radio signal according to a codeword and a frequency sub-band that are corresponding to the bearer channel, to obtain a modulated electrical signal; and modulating the modulated electrical signal to an optical wavelength corresponding to the bearer channel, to obtain a modulated optical signal; and sending the modulated optical signal to an optical network.