Flexible Functional Split for C-RAN Front-Haul Optimization

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Solution Overview

Problem

Existing centralized radio access networks (C-RANs) face challenges in efficiently managing bandwidth and latency in the front-haul network due to a fixed functional split between baseband controllers and remote units, which limits flexibility and increases bandwidth requirements.

Innovation Solution

A system and method that allow for a flexible functional split between baseband controllers and remote units in a C-RAN, enabling dynamic configuration of the interface based on supported splits, front-haul capabilities, and wireless interface configurations, thereby optimizing bandwidth and latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed functional split is used between baseband controller and remote units, then the system design is simple, but the bandwidth requirement increases and flexibility is reduced

Engineering Contradiction:
ImproveflexibilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic functional split configuration where the baseband controller and remote units can dynamically adjust their functional division based on network conditions. The baseband controller determines the functional split point and configures the interface accordingly, allowing the system to adapt to different bandwidth and latency requirements without being locked into a fixed architecture.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of functional split position based on network conditions. By allowing the functional split to occur at different points in the baseband processing chain (e.g., before or after certain processing stages), the system can optimize the balance between bandwidth consumption and processing capability without increasing overall system complexity.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If time-domain I/Q data is communicated over front-haul, then the functional split is simple, but the bandwidth requirement increases

Engineering Contradiction:
Improvebandwidth efficiencyVSAvoidinterface complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The system changes the data representation parameter by allowing the functional split to occur at different points in the baseband processing chain. This enables the use of frequency-domain data or processed baseband data instead of raw time-domain I/Q data, reducing the bandwidth requirement while maintaining interface simplicity through standardized configuration protocols.

Inventive Principle:
Principle #35Parameter changes

3Loss of time

If a fixed functional split is used, then the implementation is straightforward, but the latency performance worsens

Engineering Contradiction:
ImprovelatencyVSAvoidconfiguration complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The system dynamically adjusts the functional split position based on latency requirements. When low latency is needed, the functional split can be configured to process data closer to the remote unit, reducing the data processing distance and associated latency. The baseband controller manages this configuration dynamically without requiring complex manual setup.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3935915B1Flexible interface between a baseband controller and remote units of a c-ran
Publication Date: 2025.06.04 OUTDOOR WIRELESS NETWORKS LLC
  • EP3935915B1 patent drawingFigure 1
  • EP3935915B1 patent drawingFigure 2

AI summary

In one embodiment, a method comprises determining which functional splits between processing performed in a baseband controller and processing performed in a remote unit are supported by each remote unit served by the baseband controller. The method further comprises determining at least one functional split in the processing performed in the baseband controller and the processing performed in the remote units to use. The method further comprises, for each said at least one functional split and each remote unit associated with that functional split, configuring the processing performed in the baseband controller and the processing performed in that remote unit are configured to use that functional split and configuring a respective interface between the baseband controller and that remote unit are configured for communicating front-haul data therebetween using that functional split.