Dual Connectivity Interworking Architecture for LTE and 5G Mobility

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Solution Overview

Problem

Current dual connectivity solutions for different access networks, such as LTE and 5G, face challenges in maintaining seamless mobility and reducing latency and signaling complexity, especially with the introduction of 5G's high-frequency spectrum and small cell architecture, leading to frequent RAT changes and potential service interruptions.

Innovation Solution

An interworking architecture that enables dual connectivity for control plane signaling between LTE and 5G networks with minimal impact on legacy networks, using a multi-controller or common core approach to manage RRC connections and NAS contexts, allowing simultaneous RRC connections in both 4G and 5G networks and enabling efficient handover management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional inter RAT handover is used for macro cells, then handover between access networks is supported, but frequent RAT changes cause service interruptions and increased latency

Engineering Contradiction:
Improveservice continuityVSAvoidhandover latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the handover process into two distinct phases: control plane signaling handover and user plane data forwarding. This separation allows the control plane to complete handover signaling while the user plane continues data transmission, reducing service interruptions and latency during RAT changes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary action by establishing the control plane connection to the target access network before fully transitioning the user plane. The network controller prepares handover signaling and establishes control plane connectivity in advance, enabling smoother transitions and reducing handover latency.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If dual connectivity is implemented for LTE and 5G, then mobility robustness is improved, but signaling complexity and device complexity increase

Engineering Contradiction:
Improvemobility robustnessVSAvoidsignaling complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a universal network controller that can manage multiple radio access technologies (LTE and 5G) through a common interface. This multi-functional controller reduces signaling complexity by providing a standardized control plane interface while maintaining the ability to support dual connectivity and mobility across different RATs.

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

Solution Approach 2:

The network controller acts as an intermediary between the terminal and multiple access networks. It mediates control plane signaling and coordinates handover procedures, simplifying the signaling complexity by centralizing control functions rather than requiring direct signaling between the terminal and multiple network entities.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Speed

If 5G small cell architecture is deployed, then network capacity and speed are improved, but coverage area is reduced and handover frequency increases

Engineering Contradiction:
Improvedata transmission speedVSAvoidhandover frequency
Core Design Contradiction:
SpeedVSProductivity

Solution Approach 1:

The patent implements dynamic handover management where the network controller can adaptively control handover timing and parameters based on terminal mobility patterns and network conditions. This dynamic approach optimizes the balance between utilizing 5G small cells for high-speed data transmission and managing handover frequency to maintain service continuity.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3254530B1Improvements in dual connectivity for different access networks
Publication Date: 2021.10.13 NOKIA SOLUTIONS & NETWORKS OY
  • EP3254530B1 patent drawingFigure 1
  • EP3254530B1 patent drawingFigure 2
  • EP3254530B1 patent drawingFigure 3

AI summary

There are provided measures for improvements in dual connectivity for different access networks. Such measures exemplarily comprise providing control in a control plane for a terminal (UE) for access to a first access network (5G), wherein a coverage of the first access network (5G) at least partly overlaps a coverage of a second access network (4G), the terminal is capable of having access to the first access network (5G) and to the second access network (4G) in parallel, and access for the terminal to a respective access network (4G, 5G) is routed in a user plane via a respective distinct access network entity (eNB, 5GAP) and to a respective (compatible) gateway (S-GW, uGW).