Fronthaul Coordinator for C-RAN Processing Distribution

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Solution Overview

Problem

Managing transport load and optimizing processing distribution in a centralized radio access network (C-RAN) is challenging due to the need for efficient allocation of protocol layer processing among baseband processing units and remote radio heads, particularly in response to varying traffic conditions and network performance.

Innovation Solution

A centralized radio access network with a fronthaul physical layer coordinator that dynamically allocates protocol layer processing based on traffic conditions, transmission modes, and network performance, determining the optimal remote unit to serve mobile devices by comparing uplink signal power levels and selecting appropriate transmission modes such as MIMO or SIMO, and reallocating physical layer processing between fronthaul and remote units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If physical layer processing is centralized in baseband processing units, then network control and coordination are improved, but transport load on fronthaul links increases and processing efficiency decreases

Engineering Contradiction:
Improvenetwork controlVSAvoidprocessing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments physical layer processing into two parts: control functions remain centralized in baseband processing units, while data plane processing is distributed to remote radio heads. This segmentation allows network control to be maintained centrally while processing efficiency is improved through distribution, resolving the contradiction between centralized control and processing efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a fronthaul physical layer coordinator as an intermediary component between baseband processing units and remote radio heads. This coordinator manages the distribution of processing tasks, optimizing the balance between centralized control and distributed processing efficiency by coordinating resource allocation and task assignment.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Area of stationary object

If more remote radio heads are deployed to expand coverage, then wireless signal coverage is improved, but fronthaul link transport load increases

Engineering Contradiction:
Improvecoverage areaVSAvoidtransport load
Core Design Contradiction:
Area of stationary objectVSQuantity of substance

Solution Approach 1:

The patent implements dynamic processing distribution where remote radio heads can be dynamically activated or deactivated based on real-time traffic conditions and coverage requirements. This dynamic approach allows the system to expand coverage by activating additional remote radio heads only when needed, rather than maintaining constant high transport load across all deployed units.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of remote radio heads based on traffic conditions, switching between different processing modes (full processing, partial processing, or no processing) to optimize the balance between coverage area and transport load. This parameter change allows flexible adaptation to varying network demands.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If processing resources are allocated statically, then system complexity is reduced, but adaptability to varying traffic conditions deteriorates

Engineering Contradiction:
Improveallocation managementVSAvoidtraffic condition response
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements feedback mechanisms where the fronthaul physical layer coordinator continuously monitors traffic conditions and dynamically adjusts processing distribution accordingly. This feedback loop enables the system to adapt to varying traffic conditions while maintaining manageable complexity through automated decision-making algorithms.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent pre-configures multiple processing distribution scenarios and policies that can be quickly activated based on traffic conditions. This preliminary preparation allows the system to respond adaptively to varying conditions without requiring complex real-time calculations, thus maintaining lower system complexity while improving adaptability.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3531775A1Distributed processing in a centralized radio access network
Publication Date: 2019.08.28 ANDREW WIRELESS SYSTEMS GMBH(DE)
  • EP3531775A1 patent drawingFigure 1
  • EP3531775A1 patent drawingFigure 2
  • EP3531775A1 patent drawingFigure 3

AI summary

Certain features relate to a centralized radio access network (C-RAN) that can flexibly and dynamically allocate protocol layer processing among baseband processing units and remote units. A C-RAN can be configured to include a media access control ("MAC") scheduler and a fronthaul physical layer coordinator. The fronthaul physical layer coordinator can include a fronthaul physical layer scheduler, which can allocate spatial resources by determining the specific remote unit(s) that should serve a given mobile device. The MAC scheduler can allocate time/frequency resources to user devices communicating with the remote units. The fronthaul physical layer coordinator or the MAC scheduler can also determine the optimal transmission modes remote units can use to serve the user devices.