European Telcos Sound Alarm Over Flagging Open RAN Progress

Deutsche Telekom, Orange, and others warn the continent is falling behind the U.S. and Japan

4 min read
The top of a mobile phone mast covered in telecommunications equipment is seen against a clear blue sky.
Matthew Horwood/Getty Images

European telecom companies recently sounded an alarm that they may be falling behind the rest of the world in their efforts to develop open-interface radio access network (RAN) technologies. The technologies, called Open RAN and which would provide new ways to mix and match network components by “opening up” the interfaces between them, are widely believed to be an important opportunity to drive down the costs of network deployments and allow new players to enter a rigid market.

Five companies—Deutsche Telekom, Orange, Telecom Italia, Telefónica, and Vodafonepublished a report outlining why they feel Europe as a whole is lagging behind other regions such as the U.S. and Japan in developing Open RAN. The companies point to both a lack of companies developing key components, notably silicon chips, for Open RAN technologies, as well as the need to get incumbent equipment vendors Ericsson and Nokia on board with Open RAN development. And there’s a deeper issue in that the exact definition of Open RAN is still in flux, allowing different companies to prioritize different technologies and proclaim that they fall under the banner of Open RAN.

Briefly put, the cellular networks we use to send text messages and make calls have a few basic components. Cell towers receive analog signals via their antennas; radio units convert those signals to their corresponding digital versions; and then baseband units process the signals, correct errors, and route the digital signals to wherever they need to go. Traditionally, network operators like any of the five companies listed above purchase this equipment from a single vendor, be it Ericsson, Nokia, Samsung, or Huawei, to name the biggest players.

Vendors have an incentive to lock operators into their respective ecosystems by ensuring their components don’t work with components from their competitors. Frustrated by being in a captive market and the expenses associated with upgrading and rolling out networks, several operators created the O-RAN Alliance to force the development of standards and technologies that would lead to Open RAN implementation.

Olivier Simon, the Radio Innovation Director at Orange, says there are three aspects to Open RAN. The first is openness between the interfaces of different network components. The second is decoupling network software from hardware and moving more of a network’s operations into the cloud. And the third is increased intelligence: letting AI and machine learning techniques manage more of the network’s performance. “I think everyone agrees there are these three aspects,” says Simon, “but what becomes more tricky is that none of them are mandatory.”

For example, a recent report that calls out the difficulties in getting the Open RAN effort to coalesce around an established set of changes to the fundamentals of network architecture points out that Nokia has developed Open RAN software, but that its software runs only on Nokia’s hardware. Nokia’s developments do feature open component interfaces (the first issue addressed by Open RAN), but the operators authoring the report take issue with the lack of software-hardware decoupling in Nokia’s developments (the second of the three issues network carriers wish to tackle).

Nokia has pushed back on the report, explaining that its components are compliant with the O-RAN Alliance’s definitions for open interfaces. But that gets back to the issue at the core of Open RAN development: Do the three aspects have equal weight, and in what ways should they be prioritized and implemented? Nokia argues that its components are Open RAN-compliant because they have open interfaces. The operators that authored the report feel that’s not enough because the Nokia components don't adequately prioritize the other emerging aspects they say are critical to the success of the effort.

There is a sense from the operators that these kinds of back-and-forth arguments about what makes a particular component compliant are stymying Open RAN development in Europe. “It’s more an ecosystem question than a deep technical question,” says Simon. The network operators consider Ericsson and Nokia to be important parts of Europe’s telecom ecosystem because of their global dominance in supplying equipment. But there's a downside to having these telecom titans around, because it can be difficult for large incumbents in an industry to react swiftly to a new technology.

That has allowed U.S.-based companies like Mavenir and Parallel Wireless, and Japanese companies like Rakuten, to set the pace for Open RAN development, according to an email from Fransz Seiser, the Vice President of Access Disaggregation at Deutsche Telekom. That said, Rakuten (a Japanese network operator) has enlisted Nokia to develop and build its Open RAN network using equipment from multiple vendors, which Nokia points to as another piece of evidence that it is committed to Open RAN development. Still, it could be argued that the Rakuten-Nokia multi-vendor deployment, while prioritizing the open interface aspect, yet again fails to satisfactorily focus on the mission to decouple software and hardware). Seiser echoes Nokia's sense of things, insomuch as the company has demonstrated progress with its recent introduction of multi-vendor support.

Tanveer Saad, the Head of Edge Cloud Innovation and Ecosystems at Nokia, says that Nokia is taking a bigger responsibility as a “solution provider.” “We are actually building the solution with different components from our ecosystem players, so it can be a multi-vendor kind of environment.” On the one hand, Nokia has demonstrated a desire to ‘move quick’ in response to the disruption created by Open RAN by developing multi-vendor solutions like the one for Rakuten. On the other, the company seems to be hoping that it can maintain dominance as an end-to-end network provider, albeit by offering options with multiple vendors’ components instead of just their own.

Also driving the sense that Europe is falling behind is a lack of companies such as Broadcom, Intel, and Qualcomm producing silicon chips that will ultimately be integral to Open RAN's success. These chips will be vital for the development of AI that can manage networks. While the consensus is that this third aspect of Open RAN is the farthest in the future, the operators argue that Europe should begin investing in alternatives to existing chip manufacturers in order to shore up that weakness in the continent's network communications ecosystem.

Open RAN surprised some in the industry with how quickly it has risen to prominence. The O-RAN Alliance was founded in 2018 with just five members. It now has over 260 members. Cellular “generations” such as 4G and 5G typically exist on a ten-year cycle of research, standardization, and commercialization. Open RAN is moving much faster, and even despite the recent concerns about lagging behind—or perhaps because of them—there is still a sense in the industry that Open RAN will make a big impact in the coming years.

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The Inner Beauty of Basic Electronics

Open Circuits showcases the surprising complexity of passive components

5 min read
A photo of a high-stability film resistor with the letters "MIS" in yellow.
All photos by Eric Schlaepfer & Windell H. Oskay

Eric Schlaepfer was trying to fix a broken piece of test equipment when he came across the cause of the problem—a troubled tantalum capacitor. The component had somehow shorted out, and he wanted to know why. So he polished it down for a look inside. He never found the source of the short, but he and his collaborator, Windell H. Oskay, discovered something even better: a breathtaking hidden world inside electronics. What followed were hours and hours of polishing, cleaning, and photography that resulted in Open Circuits: The Inner Beauty of Electronic Components (No Starch Press, 2022), an excerpt of which follows. As the authors write, everything about these components is deliberately designed to meet specific technical needs, but that design leads to “accidental beauty: the emergent aesthetics of things you were never expected to see.”

From a book that spans the wide world of electronics, what we at IEEE Spectrum found surprisingly compelling were the insides of things we don’t spend much time thinking about, passive components. Transistors, LEDs, and other semiconductors may be where the action is, but the simple physics of resistors, capacitors, and inductors have their own sort of splendor.

High-Stability Film Resistor

A photo of a high-stability film resistor with the letters "MIS" in yellow.

All photos by Eric Schlaepfer & Windell H. Oskay

This high-stability film resistor, about 4 millimeters in diameter, is made in much the same way as its inexpensive carbon-film cousin, but with exacting precision. A ceramic rod is coated with a fine layer of resistive film (thin metal, metal oxide, or carbon) and then a perfectly uniform helical groove is machined into the film.

Instead of coating the resistor with an epoxy, it’s hermetically sealed in a lustrous little glass envelope. This makes the resistor more robust, ideal for specialized cases such as precision reference instrumentation, where long-term stability of the resistor is critical. The glass envelope provides better isolation against moisture and other environmental changes than standard coatings like epoxy.

15-Turn Trimmer Potentiometer

A photo of a blue chip
A photo of a blue chip on a circuit board.

It takes 15 rotations of an adjustment screw to move a 15-turn trimmer potentiometer from one end of its resistive range to the other. Circuits that need to be adjusted with fine resolution control use this type of trimmer pot instead of the single-turn variety.

The resistive element in this trimmer is a strip of cermet—a composite of ceramic and metal—silk-screened on a white ceramic substrate. Screen-printed metal links each end of the strip to the connecting wires. It’s a flattened, linear version of the horseshoe-shaped resistive element in single-turn trimmers.

Turning the adjustment screw moves a plastic slider along a track. The wiper is a spring finger, a spring-loaded metal contact, attached to the slider. It makes contact between a metal strip and the selected point on the strip of resistive film.

Ceramic Disc Capacitor

A cutaway of a Ceramic Disc Capacitor
A photo of a Ceramic Disc Capacitor

Capacitors are fundamental electronic components that store energy in the form of static electricity. They’re used in countless ways, including for bulk energy storage, to smooth out electronic signals, and as computer memory cells. The simplest capacitor consists of two parallel metal plates with a gap between them, but capacitors can take many forms so long as there are two conductive surfaces, called electrodes, separated by an insulator.

A ceramic disc capacitor is a low-cost capacitor that is frequently found in appliances and toys. Its insulator is a ceramic disc, and its two parallel plates are extremely thin metal coatings that are evaporated or sputtered onto the disc’s outer surfaces. Connecting wires are attached using solder, and the whole assembly is dipped into a porous coating material that dries hard and protects the capacitor from damage.

Film Capacitor

An image of a cut away of a capacitor
A photo of a green capacitor.

Film capacitors are frequently found in high-quality audio equipment, such as headphone amplifiers, record players, graphic equalizers, and radio tuners. Their key feature is that the dielectric material is a plastic film, such as polyester or polypropylene.

The metal electrodes of this film capacitor are vacuum-deposited on the surfaces of long strips of plastic film. After the leads are attached, the films are rolled up and dipped into an epoxy that binds the assembly together. Then the completed assembly is dipped in a tough outer coating and marked with its value.

Other types of film capacitors are made by stacking flat layers of metallized plastic film, rather than rolling up layers of film.

Dipped Tantalum Capacitor

A photo of a cutaway of a Dipped Tantalum Capacitor

At the core of this capacitor is a porous pellet of tantalum metal. The pellet is made from tantalum powder and sintered, or compressed at a high temperature, into a dense, spongelike solid.

Just like a kitchen sponge, the resulting pellet has a high surface area per unit volume. The pellet is then anodized, creating an insulating oxide layer with an equally high surface area. This process packs a lot of capacitance into a compact device, using spongelike geometry rather than the stacked or rolled layers that most other capacitors use.

The device’s positive terminal, or anode, is connected directly to the tantalum metal. The negative terminal, or cathode, is formed by a thin layer of conductive manganese dioxide coating the pellet.

Axial Inductor

An image of a cutaway of a Axial Inductor
A photo of a collection of cut wires

Inductors are fundamental electronic components that store energy in the form of a magnetic field. They’re used, for example, in some types of power supplies to convert between voltages by alternately storing and releasing energy. This energy-efficient design helps maximize the battery life of cellphones and other portable electronics.

Inductors typically consist of a coil of insulated wire wrapped around a core of magnetic material like iron or ferrite, a ceramic filled with iron oxide. Current flowing around the core produces a magnetic field that acts as a sort of flywheel for current, smoothing out changes in the current as it flows through the inductor.

This axial inductor has a number of turns of varnished copper wire wrapped around a ferrite form and soldered to copper leads on its two ends. It has several layers of protection: a clear varnish over the windings, a light-green coating around the solder joints, and a striking green outer coating to protect the whole component and provide a surface for the colorful stripes that indicate its inductance value.

Power Supply Transformer

A photo of a collection of cut wires
A photo of a yellow element on a circuit board.

This transformer has multiple sets of windings and is used in a power supply to create multiple output AC voltages from a single AC input such as a wall outlet.

The small wires nearer the center are “high impedance” turns of magnet wire. These windings carry a higher voltage but a lower current. They’re protected by several layers of tape, a copper-foil electrostatic shield, and more tape.

The outer “low impedance” windings are made with thicker insulated wire and fewer turns. They handle a lower voltage but a higher current.

All of the windings are wrapped around a black plastic bobbin. Two pieces of ferrite ceramic are bonded together to form the magnetic core at the heart of the transformer.

This article appears in the February 2023 print issue.