What Does 5G Technology Mean for Power Over Ethernet?

Emerging 5G technology is bringing significant improvements to the connectivity landscape, particularly as it relates to Internet of Things (IoT) and Big Data applications. Already, consumer and organizational demand is increasing for connecting powered devices (PDs) to Ethernet networks.

While 5G advancements will continue to enhance network connectivity everywhere, network technicians will need to overcome several inherent interconnectivity challenges. It would be near impossible for techs to reconstruct every network with new power over ethernet (PoE) cable. Techs must therefore develop PoE infrastructure that bridges the interoperability gap between existing and new standards.

The Promise of 5G

With each new generation of cellular data network technology comes promises of greater speed and stability. 5G is no exception. As the latest generation becomes more widely available, consumer and commercial applications will perform better and networks will experience less downtime.

Over the past few decades, mobile technology has evolved, gaining more capabilities with each new iteration:

• 1982: 1G enabled analog voice
• 1991: 2G added digital voice and messaging
• 1998: 3G added data and multimedia services
• 2008: 4G/LTE added IP voice and data, video, and mobile internet
• 2019: 5G added IoT and Big Data support

Telecom experts estimate 5G data transmission speeds will be more than twice as fast as 4G speeds. Upload speeds will also improve dramatically.

Additionally, 5G allows mobile networks to operate on a wide variety of frequencies, leading to latency as low as one millisecond or less. These speeds are ideal—perhaps even required—for IoT sensors that need to report feedback in real-time.

Consumers and organizations are eagerly awaiting 5G enhancements to IoT-enabled appliances and devices. 5G enhances the performance of home and business PDs such as:

• IP surveillance cameras
• 802.11ac and 802.11ax access points
• LED luminaries
• 5G small cells
• Large monitors
• Advanced cameras with heat-sensing functions
• Desktop computers
• Residential appliances

As 5G is broadly deployed, PoE and related technologies that extend distances will be well-positioned to power these devices and more. However, the latest IEEE standard represents a significant shift in how PoE will be implemented from the design stage and beyond. It will take some time for the industry to fully embrace the latest standards and 5G enhancements.

The Role of PoE Cable in 5G Deployment

Despite the widespread adoption of wireless network architectures, wired connections will still be in heavy use for a few reasons:

1. It would be cost-prohibitive to replace the millions of miles of wired CAT5e cables that are already installed throughout municipal infrastructures and within homes.
2. Wired connections are less vulnerable to hackers and much more difficult to intercept versus wireless connections. Better security is a primary reason enterprise organizations choose to maintain wired network infrastructures. Most hospital systems, universities, and large governmental organizations opt for wired networks over wireless.
3. Even with 5G’s improved indoor coverage, maintaining a strong wireless signal inside buildings presents ongoing challenges for network engineers. Wireless signals are also often affected by radio wave interference and other signal interruptions. Shielded cable provides measurable quality improvements over wireless connections.

Next-Generation IEEE

At this point, pre-standard and new IEEE 802.3bt-2018-compliant PDs can share Ethernet infrastructure. Network techs will not need to change out switches or cabling to add PDs that support PoE to work alongside existing infrastructure.

Pre-standard PoE uses the IEEE 802.3af and 802.3at standards to simultaneously supply power and transmit data over an existing data connection. The latest standard, IEEE 802.3bt, permits significantly more power to be passed through.

The new standard pushes the power limit of power sourcing equipment (PSE) to 90W and that of PDs to 71.3W. This is a timely and significant advancement, as power needs have increased with the advent of new PDs. IP phones, for example, can get by with 15.4W at the power source—IP video phones and devices like pan-tilt-zoom (PTZ) IP cameras that emerged around 2009 required at least 30W.

Today’s 5G-enabled PDs include devices like PTZ security cameras, mobile kiosks, point-of-sale retail terminals, digital signage, LED lighting, and large IoT appliances, all of which require even more power. The new IEEE standard utilizes all four pairs of structured wiring to meet the increased power requirements. This is a welcome advancement that brings along the added benefit of backward compatibility.  However, the maximum distance for PoE using Category cables still remains 328 feet (100 meters).

Examining the IEEE 802.3bt Standard

The IEEE 802.3bt standard lays out several definitions for common features and power-related elements:

• A powered device (PD) is “the portion of a device that is either drawing power or requesting power by participating in the PD detection algorithm.”
• The power interface (PI) is the mechanical and electrical interface between the PSE or PD and the transmission medium.

The standard specifies that:

•  A device that is capable of becoming a PD may have the ability to draw power from an alternate power source.
• A PD requiring power from the Power Interface (PI) may simultaneously draw power from an alternate power source.

(Source: IEEE8o2.3bt standard under ‘PD PI Current Definitions,” section 1.4.324)

Notable features of the 802.3bt specification include:

• 4-pair powering, up to 71.3W at the PD and 90W at the PSE
• Backward compatibility with 802.3at and 802.3af PSE and PD equipment
• A full range of PD classifications: 3.8W (class 1), 6.5W (class 2), 13W (class 3), 25.5W (class 4), 40W (class 5), 51W (class 6), 62W (class 7), and 71.3W (class 8)
• Extensions to the PoE data link protocol for more refined power management
• Low power “sleep mode” that allows for lower power draws
• Power from PSEs
• “Dual signature” PD front-end architecture that allows a PD to operate as two PDs, one powered by each pair set
• An autoclass feature that allows for more refined power management by a PSE without relying on data link protocols
• Support of 2.5GBase-T, 5GBase-T, and 10GBase-T data links carrying PoE power

Power Considerations

Previously, PoE standards used only four of the available eight ethernet cable conductors to carry DC. To fully realize 5G advantages, IEEE calls for using all eight conductors in the latest standard.

The overarching IEEE standards committee goal is to “increase the amount of power delivered from PSEs to PDs while reducing the standby power required for PDs when asleep.”

IEEE Std 802.3bt-2018 Amendment 2 “adds power delivery using all four pairs in the structured wiring plant, resulting in greater power being available to end devices. This amendment also allows for lower standby power consumption in end devices and adds a mechanism to better manage the available power budget.”

Using all four pairs of conductors assures that the DC current will be split evenly between the two pair sets.

In addition to more power, a significant advantage of 4-pair PoE is a reduction in power lost in cabling. By using four wire pairs:

• The total end-to-end electrical resistance is reduced by a factor of two.
• The I2R loss, or copper loss, is reduced by a factor of two or more.

The result is reduced power consumption across the whole system.

Autoclass

Section 145.8.8.2 details Autoclass, an optional extension of the Physical Layer classification. Autoclass permits PSE to determine the max power drawn by PD devices connected to the network. The Autoclass extension resolves a common situation where full power is not sent to the PD.

Single and Dual Signature Specs

IEEE 802.3bt introduces two new PD topologies aimed at supporting 5G-enabled PDs: “single-signature” and “dual signature.”

• Single-signature PD uses the same Maintain Power Signature (MPS) and detection signature classifications between both pairs.
• Dual-signature PD uses independent signatures between both pairs.

The standard allows for differentiation between single and dual signature PD connections through the Connection Check feature.

Because two distinct pair sets are required, dual-signature PD requires two parallel PD interfaces. Power from each PSE is added together after each PD interface. While this is a more costly option, technicians can select the single-signature option for half the cost.

An example is a dual-signature surveillance camera where one pair connects to the camera and the other to a heater or pan-zoom motor.

The PD side will typically require:

• A transformer for each data pair coming from the PSA
• An active bridge rectifier
• An 802.3bt PD interface controller, and
• A DC/DC converter
• Schottky diodes, resistors, and capacitors

Barriers to 5G and PoE Adoption

Though the benefits of PoE for uses like connected lighting and intelligent building applications are well-publicized, some organizations are slow to evolve on this front.

One reason for hesitance is the reality of modern corporate departmental structures. The lines between information technology (IT) and operational technology (OT) teams have become blurred for many organizations, shifting the ways projects are financed and decisions are made.

OT concerns are often conflated with IT concerns, and vice versa. If an OT team wants to promote updated, intelligent building automation, but the IT team is unwilling to shoulder the cost, the process becomes muddied. This situation can prove challenging to vendors, who may find it difficult even to identify the correct decision-makers.

Still, the advantages of bringing 5G capabilities via PoE are hard to resist for companies in the know. Vendors who take the time to educate their clients about these advantages are likely to be met with success.

Remee Solutions for Power and Data at Any Distance

While IEEE has advanced its standards to accommodate the growing demand for transmitting data and power to operate a variety of PDs, the fact remains the distance limit for data running between the hub or switch to the NIC remains 100 meters or 328 feet – with the use of Category cables.  However, many of the PDs require longer distances to be powered up, regardless of the bandwidth requirements they may have.  So Remee has engineered a whole new line of cables called Activate™ Powered Cabling Solutions (PCS) to meet the wiring needs of these many devices.

Activate™ PCS provides an entire selection of cables to meet the requirements of virtually any data and power combination for a commercial application.  Their full selection of PoE Category cables are ETL verified to IEEE standards for installations under 328 feet.  For longer distances, Remee’s PCS offering  includes larger gauge copper cables to carry power to distances beyond 328 feet.  Some Activate™ Powered Cabling Solutions can extend the distance with higher bandwidths by using fiber optic cable, along with copper cable components to carry power, all under one jacket in a hybrid/composite construction.

Whatever the combination data, power and distance requirement you have, Remee’s Activate™ PCS line will provide you with the solution you need.