Power-over-Ethernet: The Missing Link Between Digital Ceilings and a New Breed of Smart Buildings

The digital era when enterprises are embracing innovative technologies.

We are in the digital era when enterprises are embracing innovative technologies to create new experiences and business opportunities. This transformation has given rise to some revolutionary applications, including digital ceilings that have gained immense popularity by connecting everything associated with lighting network-powered LED lighting solutions and other building systems into the Internet of Things (IoT).

By creating a centralized hub for lighting, building automation, analytics for predictive maintenance, and more, digital ceilings are reshaping enterprises and creating smarter buildings and the opportunity for a gamut of solutions that improve efficiency, sustainability and comfort at lower costs. They need enterprise IoT connectivity to combine network-powered sensors, Wi-Fi access points, surveillance cameras and HVAC system controls, as well as the latest Power-over-Ethernet (PoE) technology to deliver remote Layer 2 management, uninterrupted performance, and significantly higher power efficiency than was possible with earlier solutions (see Figure below).

The First Step:  Network-Powered Luminaires and PoE

Network-powered luminaires are the first step toward a digital ceiling implementation, allowing organizations to leverage existing LAN infrastructures and offer remote lighting management capabilities that translate into lower installation and operating costs. PoE, in turn, serves as a catalyst for creating a flexible solution that eliminates the need for AC wiring by enabling the network-powered LED luminaires to be connected to and powered from the corporate data network. This enables IT managers to control and optimize power utilization as a part of network management.

In addition to supporting network-powered luminaires, PoE technology eliminates the need for electric power infrastructure when installing other IP-based Powered Devices (PDs) in the digital ceiling, including IP telephones, WLAN Access Points, IP-cameras, and other IP-based terminals. It allows PDs to receive power in parallel to data over the existing Ethernet infrastructure while keeping the structured cabling safe and not interfering with concurrent network operation. PoE provides huge benefits in relation to ease of installation, saving CAPEX and OPEX, and providing a unified and safe power standard for worldwide use.

Perhaps most importantly for digital ceiling implementations, PoE is now supported by a new standard created specifically to meet the technology’s requirements for higher power as well as more efficient power management.

A New PoE Standard for Digital Ceilings

Since the ratification of the first PoE standard in 2003, PoE use has increased dramatically and made headway into many innovative applications. PoE has evolved over the years with the implementation of IEEE 802.3af, IEEE 802.3at, IEEE 802.3bt, and HDBaseT standards (see Figure below).

Now PoE has further evolved to support the digital ceiling. The new IEEE 802.3bt standard complements the digital ceiling by increasing maximum available PoE power, adding smarter “Automatic Class” functionality, and unifying the power and control layers for improved reliability.

The IEEE 802.3bt standard defining power levels of up to 90 W has proven to be significantly advantageous to key digital ceiling applications. It increases the maximum PoE power available mainly by utilizing all four pairs of the structured wiring. IEEE 802.3bt extends the power classification information exchanged during initial negotiation to allow meaningful power management capability, enabling support of multiple PoE classes, while also being backward compatible. These enhancements solve the challenge of higher power and more efficient PoE delivery systems.
In particular, the “Automatic Class” functionality of the standard allows the Power Sourcing Equipment (PSE) to determine the actual maximum power drawn by the connected PD. PSEs implementing auto class will measure the power consumption of the connected PD throughout a defined period; during this time the PD will consume the maximum power it will ever require. PSEs can set the maximum power output based on the power drawn during auto class plus margin. This unique power management feature of the IEEE 802.3bt standard turns out to be extremely beneficial to the digital ceiling application as it enables a PSE to allocate leftover power to additional light bulbs if it knows that a specific LED luminaire will draw less than its class power. This optimizes power consumption, translating into significant cost benefits. The IEEE 802.3bt whitepaper provides more insights into the next-generation PoE standard.

The new PoE standard also unifies the power and control layers. In existing lighting installations, power is provided via the AC network, while the control is performed via separate dedicated lines. In the new digital ceiling architecture following the IEEE 802.3bt standard, both functionalities are offered by the LAN network – the power is provided via DC PoE power and the control data is provided via the standard Ethernet protocol.

The specific requirement from this unified network is to be highly reliable, providing high power efficiency specifically in no-load and in full-load scenarios. In addition, the network needs to offer basic Ethernet connectivity as there is no need for high bandwidth for lighting applications. However, to support future applications and other enterprise applications like IP security and Wi-Fi, support of 10/100/1000 Mbps data rates is recommended.

To provide the above features, the networks need to support distributed architecture where the individual switches are installed close to the lights in order to lower the power losses over the cables. This means that the PoE switch needs to be plenum-rated to enable ceiling installations and requires to support lights for 1-2 rooms resulting in 6-12 PoE ports per switch. There are several other considerations when transitioning to the PoE-empowered digital ceiling.    
Deploying the PoE-Empowered Digital Ceiling

It is imperative to understand the specific requirements involved in adopting PoE-based digital ceiling solutions for smart buildings. One crucial prerequisite is that the PoE solution support full-power mode for all the ports simultaneously. At the same time, it must ensure energy-efficient operation with maximum power loss savings on the Ethernet cables during transmission. One example of this approach is the Microsemi PDS-280G fanless digital ceiling PoE switch, which supports full-power mode by providing 30 W for eight ports simultaneously, with any individual port operating at up to 72 W.  All ports remain active even while the device is performing software upgrades, and centralized management simplifies setup and maintenance. Unlike enterprise switches, it enables lighting fixtures and other Ethernet terminals to receive power and data over standard Ethernet cables in the most efficient manner possible.

Fanless operation is particularly important.  Because many applications will require that the PoE solution be deployed in the digital ceiling, it must fit inside the available ceiling space.  Choosing a fanless solution minimizes the noise levels and avoids possible disruption to the office working environment. Additionally, the solution should support a proliferation of Wi-Fi-based devices and data-intensive mobile applications that have created an astounding demand for powerful wireless Wi-Fi Access Points. High-speed PoE solutions are required, that can support network data rates of 1000 Mbps or higher for the latest 3G/4G technologies.

Other important factors for IT managers include quick and seamless installation along with the ability to manage the entire solution remotely over the network. Scalability is also important, so the PoE solution must be compatible with all IP-based PoE luminaires available in the market. In addition, the solution should support multiple building systems beyond network-powered LED luminaires, including IP-based sensors, Wi-Fi Access Points, IP surveillance cameras, and HVAC system controls.

A proper evaluation is necessary to ensure the PoE solution is full-proof. It should leverage the latest in PoE for ideal network planning and optimal power consumption while offering the desired level of flexibility. Unlike enterprise switches, it should enable lighting fixtures and other Ethernet terminals to receive power and data over standard Ethernet cables in the most efficient manner possible.

Powering the Future

PoE technology is successfully empowering the digital ceiling transformation, paving the way for smart buildings with enterprise-grade IoT. Many leading vendors are ensuring that their products fit suitably into the digital ceiling ecosystem, further strengthening the IoT capabilities and pushing the boundaries of what can be achieved.

The new PoE-empowered digital ceiling is here to support emerging trends in the smart buildings space. By connecting multiple systems such as lighting and building automation over a single IP network, they offer next-generation connected buildings that deliver a more productive workplace and facility infrastructure. 

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This article was originally published on PowerSystemDesign.com.

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