Power over Ethernet Switch for Cell Tower Power Delivery

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Solution Overview

Problem

The high cost and vulnerability to theft of copper DC cables used for powering remote radio heads at cell towers, along with the need for extensive surge protection and structural modifications, pose significant challenges in terms of expense and service disruption.

Innovation Solution

Implementing a Power over Ethernet (PoE) system that uses thinner conductors with heavy PVC cladding, reducing the need for high-capacity surge protectors and discouraging theft, while also facilitating efficient load distribution and power management through a PoE architecture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If DC cables with higher current carrying capacity are used to compensate for voltage drop, then power delivery capability is improved, but cable cost and surge protection cost increase

Engineering Contradiction:

Improvepower delivery capabilityVSAvoidcable cost

Core Design Contradiction:

PowerVSQuantity of substance

Solution Approach 1:

The patent segments the power delivery function by introducing a DC-DC converter at the tower top that can step up voltage from lower capacity cables, allowing thinner cables to deliver equivalent power through voltage conversion rather than relying solely on cable gauge

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the electrical parameters by using DC-DC conversion to transform voltage and current characteristics, allowing the system to use lower current carrying capacity cables while maintaining power delivery capability through voltage step-up conversion

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If larger gauge DC cables are used to reduce voltage drop, then power transmission efficiency is improved, but cable weight and surge protection requirements increase

Engineering Contradiction:

Improvevoltage dropVSAvoidcable weight

Core Design Contradiction:

Loss of energyVSWeight of stationary object

Solution Approach 1:

The patent introduces a DC-DC converter as a separate functional module at the tower top that handles voltage regulation, allowing the use of lighter cables since the converter compensates for voltage drop rather than relying on heavy gauge cables

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the approach to voltage drop compensation by using active DC-DC conversion rather than passive cable sizing, dynamically adjusting voltage parameters to maintain efficiency while using lighter cable infrastructure

Inventive Principle:

Principle #35Parameter changes

3Power

If copper DC cables are used for power delivery, then electrical conductivity is improved, but theft vulnerability and security costs increase

Engineering Contradiction:

Improveelectrical conductivityVSAvoidtheft vulnerability

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent replaces expensive, theft-prone copper cables with more affordable alternative conductor materials that have adequate conductivity for the application, reducing the economic incentive for theft while maintaining functional performance

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent uses composite or alternative materials for cable conductors that combine adequate electrical conductivity with theft-deterrent properties, such as aluminum or aluminum alloys that are less valuable and less frequently targeted by thieves

Inventive Principle:

Principle #40Composite materials

4Reliability

If DC surge protection is installed at tower top to protect against lightning strikes, then system reliability is improved, but installation complexity and cost increase

Engineering Contradiction:

Improvesurge protectionVSAvoidsurge protection system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the DC-DC converter function with DC surge protection capabilities in an integrated unit, eliminating the need for separate surge protection devices and reducing overall system complexity while maintaining reliability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent designs the DC-DC converter to perform multiple functions including voltage conversion, voltage regulation, and surge protection, reducing the total number of components needed and simplifying the overall power delivery system

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10164780B2Systems, methods, and computer readable storage device for delivering power to tower equipment

Publication Date: 2018.12.25 AT&T MOBILITY II LLC

AI summary

A cell site includes a tower and a power over Ethernet system to power devices on the tower. The power over Ethernet system includes a power over Ethernet switch and a multiplexing box. Ethernet cables connect output ports of the power over Ethernet switch to input ports of the multiplexing box. A power plant is connected to the input of the power over Ethernet switch. Devices are connected to the output ports of the multiplexing box. The power over Ethernet system also includes a power management control.