Moving Relay Station Cell Selection for Adaptive Network Coverage

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Solution Overview

Problem

Conventional relay stations installed at fixed locations struggle to flexibly adjust communication cell configurations, leading to potential under-expansion of high-demand areas and over-expansion of low-demand areas as they move through various terrestrial and non-terrestrial communication cells.

Innovation Solution

A communication control apparatus and method that includes a movement information acquisition unit, an expansion cell selection unit, and a connection control unit to select and expand appropriate communication cells based on the movement information of a movable relay station, allowing it to connect to the selected cell effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a plurality of base stations are connected to a single core network device, then network resource sharing and cost reduction are achieved, but communication quality deteriorates when the base station is located far from the core network device

Engineering Contradiction:
Improvenetwork structure complexityVSAvoidcommunication quality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The network is segmented into multiple access control units, each responsible for a specific group of base stations. This segmentation allows base stations to be managed in smaller, more manageable groups, reducing the distance and communication overhead between base stations and the core network device while maintaining resource sharing benefits.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a hierarchical dimension to the network structure by adding access control units between base stations and the core network device. This creates a multi-level hierarchy that reduces the effective communication distance in the network topology while preserving the centralized resource management capabilities.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If communication control messages are transmitted using existing random access procedures, then implementation simplicity is maintained, but message collision and access failures increase under high load conditions

Engineering Contradiction:
Improvecontrol message transmission complexityVSAvoidcommunication control message transmission reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The access control unit pre-allocates dedicated random access resources to specific base stations based on their uplink-downlink configuration patterns. This preliminary assignment of resources prevents collisions before they occur, as each base station knows in advance which time-frequency resources to use for communication control messages.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system enables base stations to autonomously determine their communication control message transmission resources based on pre-configured rules and their specific uplink-downlink patterns. Each base station serves itself by selecting appropriate resources without requiring dynamic scheduling or complex coordination, reducing control overhead while avoiding collisions.

Inventive Principle:
Principle #25Self-service

3Productivity

If synchronous hybrid FDMA/TDD-FDD operation is implemented, then frequency resource utilization is improved, but interference management complexity and implementation difficulty increase

Engineering Contradiction:
Improvefrequency resource utilizationVSAvoidsynchronization and interference management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies different FDMA/TDD-FDD operation modes to different local contexts based on uplink-downlink configuration patterns. Access control units manage base stations with similar patterns together, allowing synchronous operation within groups while maintaining flexibility across the entire network. This local adaptation reduces interference management complexity compared to universal synchronous operation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system creates equipotential conditions by ensuring that base stations operating in the same access control unit follow identical timing and frequency reference patterns. This synchronization within groups eliminates inter-cell interference while maintaining the benefits of hybrid FDMA/TDD-FDD operation, balancing resource utilization with manageable complexity.

Inventive Principle:
Principle #12Equipotentiality

Data Source

PatentEP4432717B1Communication control device, communication control method, and communication control program
Publication Date: 2026.05.06 RAKUTEN MOBILE INC
  • EP4432717B1 patent drawingFigure 1
  • EP4432717B1 patent drawingFigure 2
  • EP4432717B1 patent drawingFigure 3

AI summary

A communication control apparatus 3 includes: a movement information acquisition unit 31 that acquires movement information concerning the movement of a relay station RN that can communicate with a terrestrial base station 111 or a non-terrestrial base station 131 and expand the terrestrial communication cell 112 or the non-terrestrial communication cell 132 provided by the base station 111 or 131; an expansion cell selection unit 33 that selects a communication cell 112 or 132 to be expanded by the moving relay station RN based on the movement information; and a connection control unit 35 that connects the relay station RN to the base station 111 or 131 that provides the selected communication cell 112 or 132. The relay station RN is installed to a movable vehicle V (Figure 3).