Dynamic Protocol Split in Cellular Base Station Clusters

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Solution Overview

Problem

In centralized radio access networks, determining the optimal protocol split between central and distributed units is challenging due to the need for balancing capacity links while ensuring Quality of Service, especially when there are changes in the membership of distributed base station units.

Innovation Solution

A method is introduced where the membership of distributed base station units is monitored, and upon changes in neighboring relationships, a handover of new distributed units to a central unit is initiated, allowing for reconfiguration of protocol splits to ensure all units within a cluster use the same functional split, optimizing communication and reducing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If more protocol layers are implemented in the central unit, then coordination across multiple distributed units is improved and Quality of Service is enhanced, but higher capacity links are required between the central unit and distributed units

Engineering Contradiction:
ImproveQuality of ServiceVSAvoidlink capacity
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent implements dynamic functional splitting where the division of protocol layers between central and distributed units is not fixed but can be adjusted based on network conditions, cluster membership changes, and capacity requirements. This allows the system to optimize the balance between coordination capability and link capacity requirements in real-time.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of functional split configuration based on detected cluster membership changes. When a distributed unit joins or leaves a cluster, the system reconfigures which protocol layers are implemented centrally versus distributedly, thereby adapting the link capacity requirements to match the actual network topology and service needs.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If protocol splits are reconfigured to optimize Quality of Service, then network coordination is improved, but system complexity increases due to handover and reconfiguration procedures

Engineering Contradiction:
Improvenetwork coordinationVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system implements self-service through automated detection of cluster membership changes and autonomous initiation of handover procedures. The network nodes automatically detect when a distributed unit joins or leaves a cluster, trigger appropriate handover processes, and reconfigure functional splits without requiring manual intervention, thereby managing complexity through automation rather than simplification.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses feedback mechanisms where network nodes continuously monitor cluster membership status and use this information to trigger reconfiguration events. This closed-loop feedback ensures that functional splits are optimized based on actual network conditions while maintaining manageable complexity through event-driven rather than continuous control.

Inventive Principle:
Principle #23Feedback

3Stability of the object's composition

If handover procedures are initiated for new distributed units, then consistent functional splits are achieved across the cluster, but handover time and signaling overhead increase

Engineering Contradiction:
Improvefunctional split consistencyVSAvoidhandover time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The system performs preliminary actions by pre-configuring functional split parameters and preparing handover resources before actual cluster membership changes occur. When a distributed unit is detected to join or leave a cluster, the handover and reconfiguration processes are already prepared, reducing the actual execution time and signaling overhead during the transition.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3627877B1Cellular telecommunications network
Publication Date: 2021.09.15 BRITISH TELECOM PLC
  • EP3627877B1 patent drawingFigure 1
  • EP3627877B1 patent drawingFigure 2
  • EP3627877B1 patent drawingFigure 3a

AI summary

This invention relates to a method in a cellular telecommunications network, the cellular telecommunications network having a first central base station unit connecting to each of a plurality of distributed base station units, the method comprising the steps of: identifying a cluster of distributed base station units within the plurality of distributed base station units, wherein each member of the cluster has a neighbouring relationship with another member of the cluster that satisfies a threshold; using a first functional split in which a first set of protocol functions are implemented in the first central base station unit and a second set of protocol functions are implemented by each member of the cluster of distributed base station units; identifying a change in the membership of the cluster of distributed base station units; and, in response, causing the first central base station unit and each member of the cluster of distributed base station units to implement a second functional split in which a third set of protocol functions are implemented in the first central base station unit and a fourth set of protocol functions are implemented by each member of the cluster of distributed base station units.