Modular LTE IP Phone Retrofit for Public-Private Call Handoff

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Solution Overview

Problem

Businesses face challenges in integrating Long-Term Evolution (LTE) connectivity with existing IP phone systems, particularly in older buildings with substantial concrete structures, due to high costs and inflexible hardware requirements, which often result in deteriorated signal strength and penetration issues.

Innovation Solution

A dual-functional modular system that equips existing IP phones with wireless broadband capabilities and orchestrates seamless handoffs from public cellular networks to a private business system, using modular LTE upgrade units that monitor signal strength and connectivity, enabling a mesh network and automatic transitions between networks to maintain continuous connectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dedicated desk phones with LTE connectivity are deployed, then LTE capabilities are enabled, but hardware investment costs increase and flexibility is reduced

Engineering Contradiction:
ImproveLTE connectivityVSAvoidhardware investment
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a modular LTE upgrade unit that can be attached to existing IP phones through a PKM interface, enabling these phones to function with both traditional wired connectivity and wireless LTE capabilities. This multi-functionality allows businesses to maintain their existing phone infrastructure while adding LTE capability, avoiding the need to invest in entirely new dedicated LTE desk phones.

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

Solution Approach 2:

The LTE upgrade unit is designed as a modular component that nests within or attaches to the existing IP phone system architecture. The unit integrates with the existing phone through the PKM interface, allowing the LTE functionality to be embedded within the existing hardware framework rather than requiring separate dedicated devices.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Adaptability or versatility

If LTE connectivity is integrated in older buildings with concrete structures, then mobile connectivity is provided, but signal strength deteriorates due to physical barriers

Engineering Contradiction:
Improvemobile connectivityVSAvoidsignal strength
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a hybrid communication system that acts as an intermediary between the public LTE network and the private IP network. The system continuously monitors signal strength from both networks and dynamically selects the optimal path for call transmission, using the private IP network as a mediator to bypass physical barriers when public LTE signal is weak.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements dynamic network selection that continuously adapts to changing signal conditions. The handoff controller monitors signal strength in real-time and automatically transitions calls between public LTE and private IP networks based on current conditions, providing adaptive connectivity that responds to the dynamic environment of older buildings with concrete structures.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If existing IP phones are retrofitted with LTE capabilities, then infrastructure costs are reduced, but seamless connectivity and handoff capabilities are compromised

Engineering Contradiction:
Improveinfrastructure costVSAvoidseamless connectivity
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent implements a feedback mechanism where the handoff controller continuously monitors signal strength and connectivity status from both the public LTE network and the private IP network. This real-time feedback enables the system to make informed decisions about when to handoff calls, ensuring seamless connectivity while using the cost-effective modular retrofit approach.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary actions by pre-configuring the modular LTE upgrade units with dual network interface capabilities and establishing the handoff controller before any call occurs. This preliminary setup ensures that when a call is active, the system can immediately execute seamless handoffs without requiring complex real-time configurations or additional infrastructure.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4712566A1Wireless broadband communication integration process for business IP phone system
Publication Date: 2026.03.18 MITEL CORP
  • EP4712566A1 patent drawingFigure 1
  • EP4712566A1 patent drawingFigure 2
  • EP4712566A1 patent drawing

AI summary

Systems and methods for a dual-functional modular system for providing Internet Protocol (IP) phones with wireless broadband capabilities and a handoff from public cellular networks to a private business system. The method may include providing a plurality of IP phones with one or more modular Long-Term Evolution (LTE) upgrade units, wherein the plurality of IP phones gain LTE endpoint features; configuring the one or more units to connect to a private IP network; continuously monitoring signal strength of a public LTE network and the private IP network; detecting a mobile device with an active call; when the private IP network provides a more stable connection, initiating a handoff from the public LTE network to the IP network; transferring the active call data to an available LTE-equipped IP phone; monitoring the IP network; and when the IP network becomes unstable, reverting service of the active call to the public LTE network.