Small Cell Bearer Management for Mobile Communication

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Solution Overview

Problem

Existing LTE systems lack methods for adding or removing a radio base station managing a small cell from the transmission path of a mobile station when it transitions between macro and small cells, impacting the processing load of radio base stations.

Innovation Solution

A mobile communication method that dynamically changes the transmission path by using a gateway device and mobility management node to manage the addition or deletion of a radio base station managing a small cell, minimizing the impact on existing architecture by establishing or releasing U-plane bearers between the radio base station eNB, PhNB, and the mobile station UE.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a radio base station PhNB managing a small cell is added to the transmission path of a mobile station UE in a macro cell, then the broadband performance and high-speed communication capability are improved, but the device complexity and processing load on the radio base station eNB increase

Engineering Contradiction:
Improvecommunication speedVSAvoidtransmission path complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The transmission path is segmented into multiple bearers: a control plane bearer for signaling between UE and eNB, and a user plane bearer for data transmission through PhNB. This segmentation allows the control functions to remain at the eNB while user data flows through the small cell, reducing the processing burden on the eNB and enabling parallel handling of control and data traffic.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The macro base station eNB acts as an intermediary between the gateway device and the small cell base station PhNB. It manages the control plane signaling and coordinates the user plane data flow, allowing the PhNB to be integrated into the transmission path without requiring direct complex interactions between the UE and PhNB, thus simplifying the overall system architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the radio base station PhNB is deleted from the transmission path when the mobile station UE moves to a different small cell or macro cell, then the adaptability to mobility is improved, but the data transmission efficiency and communication speed may deteriorate

Engineering Contradiction:
Improvemobility adaptabilityVSAvoiddata transmission speed
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The system performs preliminary actions by establishing control plane bearers and coordinating resources before the UE actually moves to a new cell. The eNB proactively manages the bearer setup and modification in advance of handover events, ensuring that data transmission paths are prepared and optimized before mobility changes occur, thus maintaining high transmission speeds during transitions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The transmission path configuration is made dynamic through the establishment and release of user plane bearers. The system can dynamically add PhNB to the transmission path when UE enters a small cell coverage area and dynamically remove it when UE moves away, allowing the network to adapt to mobility while maintaining optimal data transmission paths at all times.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If the radio base station PhNB is added or deleted from the transmission path, then the network flexibility is improved, but the processing load on the radio base station eNB and PhNB increases

Engineering Contradiction:
Improvenetwork flexibilityVSAvoidprocessing load
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The invention extracts the user plane data transmission function from the eNB and delegates it to the PhNB through dedicated user plane bearers. This extraction allows the eNB to focus on control plane functions while PhNB handles user data traffic, distributing the processing load more efficiently across the network and reducing the energy consumption of individual base stations.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The eNB serves multiple functions simultaneously: it acts as a control plane anchor for all UEs in its coverage area, manages bearer setup and modification for small cell integration, and coordinates with the gateway device. This multi-functionality is achieved through standardized interfaces and protocols that allow the eNB to handle diverse tasks without proportionally increasing its processing load.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3442270B1Mobile communication method
Publication Date: 2020.03.11 NTT DOCOMO INC
  • EP3442270B1 patent drawingFigure 1
  • EP3442270B1 patent drawingFigure 2
  • EP3442270B1 patent drawingFigure 3

AI summary

A mobile communication method comprising the steps of: in a case where a mobile station is in communication in a macro cell managed by a first radio base station, and in a case where a second radio base station, which manages a small cell having a coverage including a location where the mobile station is present, is selected as a transmission path of user data of the mobile station, causing the first radio base station to start addition processing of adding the second radio base station to the transmission path of the user data of the mobile station; causing the second radio base station to reset header-compression related information, security setting information, and sequence-number management information in the addition processing; and causing the first radio base station to forward downlink user data destined for the mobile station to the second radio base station, in the addition processing, wherein the second radio base station has no Radio Resource Control, RRC, layer function.