O-RAN Fronthaul Interface for Multi-RAT Transport

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Solution Overview

Problem

Current O-RAN standards do not support front-haul transport for FS-8 Radio Access Technologies (RATs), limiting the deployment of 2G and 3G networks and preventing seamless integration with 4G and 5G systems, as they lack the capability to carry time domain IQ samples and control information over the fronthaul interface.

Innovation Solution

The system enhances O-RAN fronthaul interfaces to enable the transport of time domain IQ samples and control information for FS-8 RATs, allowing for the migration of complex radio functionalities like frequency hopping, carrier aggregation, and power control to the O-DU software, while maintaining compatibility with existing FS-7.2x RATs, thereby extending O-RAN capabilities to support true multi-RAT operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If O-RAN fronthaul interface is used for FS-7.2x RATs (4G/5G), then interoperability and flexibility are improved, but support for FS-8 RATs (2G/3G) is lost

Engineering Contradiction:
Improvemulti-RAT supportVSAvoidinterface complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the fronthaul interface into separate processing paths: one path handles FS-7.2x RATs using standard O-RAN protocols, while another path handles FS-8 RATs through legacy interface adapters. This segmentation allows each RAT type to be processed independently with appropriate protocols, enabling multi-RAT support without forcing a single complex interface design on all systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces legacy interface adapters as intermediary components that bridge between traditional FS-8 RAT interfaces and the O-RAN fronthaul infrastructure. These adapters translate and convert legacy 2G/3G interface protocols into O-RAN compatible formats, allowing FS-8 RATs to communicate over the O-RAN fronthaul without requiring direct native support, thus maintaining versatility while managing interface complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If FS-8 RATs are integrated into O-RAN, then network deployment flexibility is improved, but standard compatibility is worsened

Engineering Contradiction:
Improvedeployment flexibilityVSAvoidstandard compliance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies parameter changes by transforming the interface protocol parameters between legacy FS-8 RAT formats and O-RAN FS-7.2x formats. The legacy interface adapters modify key parameters such as data encoding schemes, packet structures, and timing synchronization parameters to convert 2G/3G legacy protocols into O-RAN compatible formats, enabling standard compliance while maintaining deployment flexibility for legacy systems.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4087141A1Interfacing 2g and 3g cellular radio communication systems to a packet-based ecpri/roe/o-ran compliant front haul interface
Publication Date: 2022.11.09 MAVENIR SYST INC
  • EP4087141A1 patent drawingFigure 1
  • EP4087141A1 patent drawingFigure 2
  • EP4087141A1 patent drawingFigure 3A

AI summary

There is provided, an open radio access network distributed unit (O-DU) having an electronic module that performs an FS-8 Radio Access Technology (RAT) functionality such as frequency hopping, downlink (DL) carrier aggregation, uplink (UL) channelization, power control, and fast automatic gain control (AGC).