Base Station Synchronization via Handover Timing Extraction

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Solution Overview

Problem

Current methods for radio network synchronization in mobile communication networks, such as GPS-based and Precision Time Protocol (PTP), are costly and insufficiently accurate, especially in indoor environments with limited access to GPS signals and low-tier backhaul connections.

Innovation Solution

A method that utilizes terminal-based synchronization procedures to perform predictable forced inter-node handover procedures, allowing base stations to adjust their timing references by triggering handover events with user equipment to obtain timing information from neighboring base stations, enhancing synchronization accuracy without requiring expensive hardware.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If GPS-based synchronization methods are used, then synchronization accuracy is improved, but hardware cost and installation complexity increase

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidhardware cost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces expensive GPS receivers with inexpensive existing base station hardware that can perform synchronized handover procedures. The synchronization function is achieved through software-controlled handover timing rather than dedicated expensive hardware, effectively using cheaper resources to achieve the same synchronization goal.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The base station entities perform multiple functions: their existing hardware is used both for normal communication operations and for synchronization measurements during handover procedures. The same base station infrastructure that handles user traffic is also utilized for timing reference acquisition, eliminating the need for separate dedicated synchronization hardware.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If PTP protocol is used for synchronization, then synchronization accuracy is improved, but hardware cost increases due to precision clock requirements

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidhardware cost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent avoids requiring expensive precision clocks in each base station by using the existing base station clocks combined with synchronized handover measurements. The timing information is extracted from regular handover procedures rather than from dedicated precision timing hardware, achieving PTP-level accuracy without PTP hardware costs.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The base station entities themselves generate and provide the timing information needed for synchronization through their normal operation during handover procedures. Rather than requiring external precision time sources or dedicated timing hardware, the system uses the base stations' own operational signals to establish synchronization references.

Inventive Principle:
Principle #25Self-service

3Reliability

If GPS receivers are installed in each base station, then synchronization reliability is improved, but ease of manufacture and deployment deteriorates

Engineering Contradiction:
Improvesynchronization reliabilityVSAvoiddeployment complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses the existing base station hardware for dual purposes: normal communication functions and synchronization measurements. This eliminates the need for separate GPS receiver installation and configuration, simplifying deployment while maintaining synchronization reliability through the multi-functional use of existing infrastructure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The synchronization function is merged with the existing handover procedure and base station operational signals. Rather than adding a separate GPS-based synchronization system, the patent combines synchronization measurements with regular base station operations, reducing deployment complexity by integrating functions rather than adding separate systems.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of operation

If traditional handover procedures are used, then operational simplicity is maintained, but synchronization accuracy deteriorates

Engineering Contradiction:
Improveoperational simplicityVSAvoidsynchronization accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent makes the existing handover procedure serve dual purposes: maintaining user connectivity (original function) and providing synchronization measurements (new function). By extracting timing information from regular handover events, the system achieves synchronization accuracy improvement without requiring separate complex synchronization procedures, preserving operational simplicity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent continuously utilizes handover procedures for both their original purpose and for synchronization measurements. Rather than introducing intermittent dedicated synchronization events, the system extracts timing information from every handover occurrence, maintaining continuous synchronization improvement while keeping the handover process itself unchanged and simple to operate.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3094141B1Method for radio network synchronization of a mobile communication network with a local clock functionality providing a local timing reference for each base station entity, mobile communication network, base station entity, program and computer program product
Publication Date: 2020.12.16 DEUTSCHE TELEKOM AG
  • EP3094141B1 patent drawingFigure 1~2

AI summary

The invention relates to a method for radio network synchronization of a mobile communication network, wherein the mobile communication network comprises a plurality of base station entities and at least one user equipment connected to the mobile communication network, wherein each of the plurality of base station entities comprises a local clock functionality providing a local timing reference for the respective base station entity, wherein in order for a first base station entity among the plurality of base station entities to obtain an indication about the timing reference of a second base station entity among the plurality of base station entities, a handover procedure is triggered - by the first base station entity and for the user equipment - from the first base station entity to the second base station entity, wherein the method comprises the followings steps: -- in a first step, the first base station entity is the serving base station entity for the user equipment and requests the user equipment to execute a handover towards the second base station entity, -- in a second step, during the handover procedure of the user equipment towards the second base station entity, a timing information is transmitted from the second base station entity - via the user equipment - to the first base station entity, the timing information being indicative of the local timing reference of the second base station entity, -- in a third step, subsequent to the second step, the timing information is used by the first base station entity to adjust the local timing reference of the first base station entity.