Dynamic Fronthaul Load Reduction via Frequency-Domain Resource Grouping

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Solution Overview

Problem

Conventional Centralized Radio Access Network (CRAN) architectures face flexibility and scalability issues due to the burden of signal processing operations at central units, particularly with algorithms like adaptive beamforming and network coordination, which require software and hardware modifications and are limited by the number of remote units that can be connected, and existing frequency-domain transmission methods do not adequately reduce data rates over fiber links to meet modern requirements.

Innovation Solution

A method and system that dynamically reduce fronthaul load by transmitting only allocated radio resources in the frequency domain, grouping and transmitting allocated radio resources with association and allocation data between the central unit and remote units, allowing for efficient data transmission and reducing the data rate over fiber links.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional time-domain transmission methods are used in CRAN architecture, then complete signal transmission is achieved, but fiber link capacity becomes a bottleneck and scalability is limited

Engineering Contradiction:
Improvesignal transmission completenessVSAvoidscalability to number of remote units
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent transforms the transmission domain from time-domain to frequency-domain, fundamentally changing the parameter domain of signal transmission. This allows for more efficient utilization of fiber link capacity and enables dynamic resource allocation, thereby improving scalability while maintaining signal transmission completeness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the composite base-band signal into individual user signals in the frequency domain, allowing selective transmission of only allocated radio resources. This segmentation enables efficient resource utilization and reduces overall data rate requirements on fiber links, improving system scalability

Inventive Principle:
Principle #1Segmentation

2Productivity

If frequency-domain transmission is implemented, then data rate over fiber links is reduced, but signaling overhead for resource allocation increases

Engineering Contradiction:
Improvedata rate reduction over fiberVSAvoidsignaling overhead
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent extracts and transmits only the allocated radio resources in the frequency domain, separating useful signal components from unnecessary transmissions. By taking out only the essential allocated resources and their associated minimal signaling information, the system achieves significant data rate reduction while keeping signaling overhead manageable

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of transmitting complete signals for all remote units, the patent applies partial action by transmitting only the allocated radio resources that are actually needed. This selective transmission reduces data rate over fiber links while the signaling overhead remains proportional to the actual resource allocation rather than maximum potential resources

Inventive Principle:
Principle #16Partial or excessive action

3Ease of operation

If signal processing is centralized at the central unit, then coordination is simplified, but device complexity and processing burden increase

Engineering Contradiction:
Improvecoordination simplicityVSAvoidcentral unit processing burden
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent segments signal processing functions between the central unit and remote units. The central unit performs resource allocation and frequency-domain transformation, while remote units handle inverse transformation and signal processing. This segmentation reduces the processing burden on the central unit while maintaining coordination simplicity through standardized interfaces

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces frequency-domain transformation as an intermediary mechanism between centralized resource allocation and distributed signal processing. This intermediary layer enables efficient coordination by translating resource allocation decisions into frequency-domain resource blocks that can be independently processed at remote units, reducing central unit complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3158808B1Method for dynamically reducing fronthaul load between a base station and multiple remote radio units
Publication Date: 2020.02.19 TELECOM ITALIA SPA
  • EP3158808B1 patent drawingFigure 1A
  • EP3158808B1 patent drawingFigure 1B
  • EP3158808B1 patent drawingFigure 2

AI summary

A method is proposed of arranging, in a mobile communication network (100), transmission of data (S*INFO i,n ,S*CTRL n ) between user equipments (UE i ) and at least one base station (BS) comprising a central unit (CU) and at least one remote unit (RU j ) associated therewith, wherein said data (S*INFO i,n ,S*CTRL n ) comprise information data (S*INFO i,n ) and control data (S*CTRL n ) from the central unit (CU) to the at least one remote unit (RU j ), or from the at least one remote unit (RU j ) to the central unit (CU). The method comprises: allocating (115) radio resources for said data (S*INFO i,n ,S*CTRL n ) to/from the at least one remote unit (RU j ), grouping (120) the allocated radio resources (PPRB p ) into allocated radio resources groups (AG g,n ) each one comprising at least one radio resource (PPRB p ) allocated for data (S*INFO i,n ,S*CTRL n ) to/from a respective remote unit (RU j ), including (120) in each allocated radio resources group (AG g,n ) association data (A SS D) indicative of an association of the at least one allocated radio resource (PPRB p ) of that allocated radio resources group (AG g,n ) with the respective remote unit (RU j ), including (120) in each allocated radio resources group (AG g,n ) allocation data (A LL D) indicative of the allocated radio resources (PPRB p ), among said at least one allocated radio resource (PPRB p ), that have been allocated at least for the information data (S*INFO i,n ), and transmitting said allocated radio resources groups (AG g,n ) in the frequency-domain between the central unit (CU) and the at least one remote unit (RU j ).