Relay Node Handover Control in LTE-Advanced Mobile Systems

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Solution Overview

Problem

Conventional mobile communication systems lack regulation for handling handover processes when relay nodes are connected, particularly in LTE-advanced systems, leading to inefficiencies in handover processes between relay nodes and radio base stations.

Innovation Solution

A mobile communication system is designed to facilitate handover processes by establishing radio bearers between relay nodes and radio base stations, allowing control signals to be transmitted and received through these bearers, enabling seamless handovers between different relay nodes and radio base stations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If relay nodes are connected to enable extended coverage and improved connectivity, then system versatility and coverage are improved, but handover process complexity increases due to lack of regulation

Engineering Contradiction:
Improvesystem versatilityVSAvoidhandover process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces a relay node as an intermediary element between the mobile station and the radio base station. The relay node mediates the handover process by receiving control signals from the source radio base station and forwarding them to the target radio base station, thereby enabling handover functionality in extended coverage scenarios without requiring complex direct communication protocols between all network elements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Area of stationary object

If relay nodes are introduced to extend network coverage, then coverage area is improved, but control signal transmission reliability deteriorates due to additional transmission hops

Engineering Contradiction:
Improvecoverage areaVSAvoidcontrol signal transmission reliability
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent segments the control signal transmission path into distinct segments: source radio base station to relay node, and relay node to target radio base station. Each segment handles specific handover control signals independently, allowing for targeted error handling and signal validation at each hop, thereby maintaining reliability while enabling extended coverage through the relay node infrastructure.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2426976B1Mobile communication system
Publication Date: 2018.05.30 NTT DOCOMO INC
  • EP2426976B1 patent drawingFigure 1
  • EP2426976B1 patent drawingFigure 2
  • EP2426976B1 patent drawingFigure 3

AI summary

A radio base station according to the present invention comprising : a mobile communication system, a first relay node and a radio base station are connected via a radio bearer, a second relay node and a radio base station are connected via a radio bearer, a mobile station is configured so as to conduct a handover process between a first state wherein a radio bearer is established with the first relay node in order to communicate via the first relay node and the radio base station, and a second state wherein a radio bearer is established with the second relay node in order to communicate via the second relay node and the radio base station and the mobile station is configured such that in the handover process, control signals involved in the handover process are transmitted and received via the radio bearer between the first relay node and the radio base station, and via the radio bearer between the second relay node and the radio base station.