DC Power Considerations for 5G Systems

With the roll-out of 5G wireless networks, more connected devices and "things" including autonomous vehicles, telemedicine, smart cities, and automated factories will benefit from the enhanced network availability. 5G is expected to deliver downloads 100 times faster than 4G, with lower latency. IDC estimates that 152,000 new devices will be connecting to the internet every minute by 2025 with global data traffic doubling every four years. The advances in 5G will bring the higher level of performance needed to support the massive amounts of data generated by the Internet of Things (IoT) and critical communications. To ensure reliable infrastructure, robust and highly reliable DC power systems are essential to 5G's success.

5G vs. 4G 

5G networks are built on high-band spectrum or high frequencies enabling the transmission of more data at much faster speeds than over a 4G network. However, 5G's high-band spectrum is limited and can't travel well through obstacles – such as buildings, mountains, or other obstructions, and requires significantly more power. To compensate, carriers are installing a distributed network in urban areas that include many small cell sites on towers, poles, and buildings near each other along with many repeaters. However, these small radio nodes are at a higher risk of failure due to storms and accidents.

Image courtesy of UNIPOWER.

If they do lose power, they can take minutes to reboot. This is unacceptable for critical applications such as emergency services and other crucial communication and data applications. Redundant and robust DC power systems with battery backup are paramount to the "always on and always connected" performance that users require and expect.

Powering 5G Infrastructure

The migration to 5G creates different power design challenges for carriers. If DC power systems are not implemented correctly and efficiently, operators can risk not only outages but costly expenses, including replacing entire power systems and cabling. "The increased power and processing requirements of 5G infrastructure create the need for highly efficient and reliable power systems that can tolerate heavy loads. This can be fulfilled by DC power systems, which are modular and extremely efficient," explained Manoj Shankar, Senior Research Analyst, Energy and Power Systems Practice at Frost & Sullivan.

A modular, scalable and plug and play approach to DC power systems make the most sense in this distributed architecture. Incorporating DC systems that have a very robust design with long service life, greatly enhances reliability and uptime. Often carriers are not aware of how complex DC systems can be. Rectifiers, converters, batteries, battery chargers, remote monitoring, communications, and links to the overall system are essential to the entire DC power system. 

Power Considerations

The heavier load on 5G systems requires a re-thinking of the power requirements and power systems that go into 5G applications. For example, 6V to 8V voltage sags are a common problem, which means the DC power system needs to be able to immediately compensate for these sags when required and this is generally achieved by incorporating some type of boost converter(s). 

Batteries are another prime consideration. With 3G and 4G systems, the tried-and-true lead-acid battery backup systems were a good solution for cell tower base stations. Now, with thousands of 5G distributed locations, lithium-ion batteries are a better solution as they have a much longer service life and wider temperature tolerance, reducing frequent maintenance and replacement. Size and weight are also prime advantages as the heavier lead-acid batteries are difficult to fit on a 5G pole. The latest ‘smart’ lithium-ion batteries are more compact, safe, non-toxic, and incorporate advanced IoT-style communications, including remaining capacity, peak voltage, and much more; all delivered over a regular Wi-Fi connection.

Here are a few more important considerations: 

1. What is the true, peak power requirement for a distributed DC power system?
2. Are there anticipated voltage sags in the system due to cable capacity and/or length?
3. What type of redundancy is needed for power, control, backup? 
4. Are backup power calculations based on worst-case scenarios? 
5. What is “acceptable” downtime, if any?

Summary

With exponentially more connected devices, enhanced network availability, and faster downloads, high-reliability DC power systems are vital to 5G's infrastructure success. When working with a power solutions provider, make sure you have access to their applications engineers to discuss real-world experiences and the best options for configuring the optimum power system design. This is important as carriers often inherit equipment that includes older systems that are kept online and upgraded. Additionally, they may have different designs for each location. Product lead times, testing, safety standards, and long life are also key considerations.