Centralized Access Router Handover Latency Reduction

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Solution Overview

Problem

Inter-small cell handovers requiring inter-macro cell handovers cause latency in mobile broadband services due to the need for simultaneous control and user plane handovers, disrupting user experience in heterogeneous networks.

Innovation Solution

Implementing a centralized access router that buffers user data and manages handovers between macro and small cells, allowing for simultaneous two-layer handovers between macro base stations triggered by small cell associations, reducing signaling overhead and latency by resuming user plane data traffic before control plane handover completion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If inter-small cell handover is performed requiring inter-macro cell handover, then user data traffic can be offloaded to small cells, but latency increases due to simultaneous control and user plane handovers

Engineering Contradiction:

Improvenetwork capacityVSAvoidhandover latency

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent segments the handover process into two independent planes: control plane handover (between macro base stations) and user plane handover (between small cells). This allows the user plane data traffic to be handed over independently without waiting for the control plane handover to complete, thereby reducing overall handover latency while maintaining network capacity benefits

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary action by performing the user plane handover before the control plane handover is completed. The user data traffic is switched to the target small cell in advance, so that when the control plane handover finishes, the user plane is already established, eliminating the need to wait for control plane completion before resuming data transfer

Inventive Principle:

Principle #10Preliminary action

2Reliability

If simultaneous two-layer handovers are implemented, then handover completeness is ensured, but signaling overhead increases

Engineering Contradiction:

Improvehandover completenessVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the handover signaling into separate control plane signaling (for macro base station handover) and user plane signaling (for small cell handover). This segmentation allows each plane to use optimized signaling paths, reducing overall signaling overhead while ensuring both handovers are completed reliably

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary mechanism where the source macro base station coordinates the handover process by sending handover commands to both the user equipment and the target macro base station, while small cell handovers are managed independently through user plane signaling, reducing the burden on control plane signaling

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10257755B2Handover of a user equipment having offloaded user data traffic between two small cells controlled by different macro cells

Publication Date: 2019.04.09 HMD GLOBAL

AI summary

To reduce handover latency experienced by a user using a user equipment that is served for offloaded user data traffic by a first small cell, a handover between a first macro cell deploying the first small cell and a second macro cell deploying a second small cell is triggered when information indicating that the user equipment has associated with the second small cell not deployed by the first macro cell is received.