RRC Connection Segmentation for Heterogeneous Network Handover

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Solution Overview

Problem

Heterogeneous wireless communication networks face challenges with increased handovers and radio link failures due to interference between overlay and existing cellular networks, particularly when low-power cells reuse the same carrier frequency as macro cells, leading to inefficient load balancing and data/control plane traffic management.

Innovation Solution

Implementing a method where user equipment (UE) maintains simultaneous RRC connections with both a serving macro cell and an offloading low-power cell, allowing for data and control packet offloading without switching the data path, and using RRC connection reconfiguration messages to manage handovers and reduce radio link failures by coordinating between cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If low-power cells reuse the same carrier frequency as macro cells to improve spectrum utilization, then spectral efficiency is improved, but interference between cells increases leading to radio link failures

Engineering Contradiction:
Improvespectrum utilizationVSAvoidinterference
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent segments the radio resource control by introducing separate RRC entities for macro cell and low-power cell communications. The UE maintains independent RRC connections with each cell type, allowing separate control plane management. This segmentation enables the system to utilize the same frequency resources while managing interference through independent RRC protocols and separate handover procedures.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If traditional handover procedures are used in heterogeneous networks, then cell switching is achieved, but unnecessary handovers and radio link failures increase

Engineering Contradiction:
Improvehandover capabilityVSAvoidradio link stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements preliminary actions by establishing separate RRC connections with both macro cell and low-power cell before actual data offloading occurs. The UE proactively configures radio resources for both cells, performs measurements on both frequencies, and prepares handover parameters in advance. This preliminary configuration prevents sudden connection breaks during handover, reducing radio link failures.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary RRC layer that mediates between the UE and both macro cell and low-power cell. This intermediary RRC connection management allows coordinated handover procedures where the network can smoothly transition data paths while maintaining control plane connectivity. The intermediary mechanism ensures that handovers are triggered only when necessary and executed with proper coordination, reducing unnecessary handovers.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If UE switches data path to offloading cell to achieve data offloading, then load balancing is improved, but control plane management complexity increases

Engineering Contradiction:
Improvedata offloading efficiencyVSAvoidRRC connection management
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the control and data planes by allowing the UE to maintain separate RRC connections for control plane management with the macro cell while simultaneously establishing data bearers with the low-power cell. This segmentation enables data offloading to improve productivity while the control plane complexity is managed through the dedicated macro cell RRC connection, which coordinates the overall connection management.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3404961B1Method and device for handover of wireless communications in heterogeneous networks
Publication Date: 2020.08.05 BLACKBERRY LTD
  • EP3404961B1 patent drawingFigure 1
  • EP3404961B1 patent drawingFigure 2~3
  • EP3404961B1 patent drawingFigure 4A~4C

AI summary

Systems, methods, and apparatuses for data and/or control offloading and handover in heterogeneous wireless communication networks are provided. Data and/or control packets can be offloaded to a coordinating base station while a user equipment (UE) remains associated with its serving cell. The packets are still transferred between the serving base station and the core network, and the offloaded data and/or control packets are forwarded from the serving base station to the coordinating base station for transmission to the UE. Furthermore, during a handover process, the serving base station and coordinating base station may independently schedule and send a handover command to the UE to reduce the radio link failure rate.