Hybrid D2UE BS2UE Offloading for Small-Cell Capacity

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Solution Overview

Problem

Increasing the density of small-cell units in wireless networks to enhance capacity is hindered by connectivity and mobility issues, high deployment complexity, and backward compatibility challenges in conventional carrier aggregation operations.

Innovation Solution

A hybrid D2UE and BS2UE system that offloads data traffic from Macro base stations to small-node devices, allowing simultaneous communication with both the macro base station and user equipment, reducing signal processing complexity and enabling flexible node selection, while avoiding the transmission of control signals by small-node devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the density of small-cell units is increased to enhance network capacity, then cell capacity increases due to frequency reuse effects, but the number of handovers increases and quality of connectivity and mobility performance is degraded

Engineering Contradiction:
Improvecell capacityVSAvoidquality of connectivity and mobility performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent divides the network into macro base stations and small-cell units with distinct functional roles. Macro base stations handle control plane functions and mobility management, while small-cell units focus on data plane functions. This segmentation allows small cells to be densely deployed for capacity enhancement without requiring them to independently manage handovers and connectivity, thus maintaining mobility performance while increasing cell capacity.

Inventive Principle:
Principle #1Segmentation

2Reliability

If conventional carrier aggregation operations are used to improve connectivity and mobility, then quality of interworking is achieved, but the small-cell units must be perfectly controlled by the Macro base station and signal processing complexity of the Macro base station increases

Engineering Contradiction:
Improvequality of connectivity and mobilityVSAvoidsignal processing complexity of the Macro base station
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts signal processing functions from the macro base station and relocates them to small-cell units. The macro base station retains control plane functions while small-cell units independently perform data plane signal processing. This extraction reduces the signal processing complexity at the macro base station while maintaining connectivity and mobility quality through coordinated operation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a new interface and protocol between macro base stations and small-cell units that acts as an intermediary. This intermediary mechanism enables distributed signal processing at small-cell units while maintaining centralized control at macro base stations, thus reducing macro base station complexity without sacrificing connectivity quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If remote radio heads or remote antennas are utilized to reduce Macro base station complexity, then deployment flexibility is improved, but the number of handovers increases and connectivity quality is degraded

Engineering Contradiction:
Improvedeployment flexibilityVSAvoidconnectivity quality
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent implements dynamic functionality assignment where small-cell units can dynamically switch between operating as remote radio heads under macro base station control and operating as autonomous nodes with independent signal processing. This dynamic capability allows the system to optimize between deployment flexibility and connectivity quality based on operational conditions, handover patterns, and network load.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2823661B1Method and apparatus at the physical and link layer for mobile communications
Publication Date: 2020.12.30 NTT DOCOMO INC
  • EP2823661B1 patent drawingFigure 1
  • EP2823661B1 patent drawingFigure 2
  • EP2823661B1 patent drawingFigure 3

AI summary

In a telecommunications network, a system to offload data traffic from base stations to small node devices includes a small node device. The small node device includes a macro-base-station-to-small-node-device (BS2D) communication section in communication with a source base station through a first link, and a small-node-device-to-user-equipment (D2UE) communication section in wireless communication with a mobile station through a fourth link. A control unit in the source base station determines a configuration of the fourth link, a macro-base-station-to-user-equipment (BS2UE) communication section is in wireless communication with the mobile station and the source base station through a second link, and a macro-base-station-to-macro-base-station (BS2BS) communication section is in communication with a target radio base station and the source base station through a third link, and a backhaul communication section is in communication with a server.