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Learn about 5G challenges and solutions with these blog contributions from various industry experts.

Why is the O-RAN Approach Critical for Flexible 5G?

November 3, 2021

Bandwidth is everything, at least for Fifth Generation (5G) cellular wireless networks. With each generation of cellular wireless networks, the number of users and their applications and devices has grown steadily, requiring more bandwidth for more communications. To meet this increased demand for bandwidth, 5G networks will need to reach much higher frequencies than earlier generations.

5G networks operate within the RF/microwave ranges of earlier generations, below 6 GHz, but they will also extend well into the millimeter wave (mmWave) frequency range, from 24 GHz to about 52 GHz. For maximum network efficiency, system designers, network operators, and service providers are exploring a change in radio access network (RAN) architecture, from the proprietary hardware and software and the centralized approach of earlier generations to an open RAN (O-RAN) architecture. An O-RAN approach would open the market for 5G network hardware, such as antennas, amplifiers, filters, and network software. 5G systems based on an O-RAN infrastructure can speed the implementation of 5G networks and create new opportunities for suppliers of the hardware components and software needed for those networks.

Wireless cellular networks have traditionally operated on closed RAN structures, with network infrastructure equipment such as antennas and base stations built with proprietary equipment from a handful of select suppliers. In this model, the wireless network structure is tightly controlled and closed except to those suppliers. This structure ensures well-designed interoperability of the components and coordination of network functions by the software. Still, sources for backup or replacement parts are limited, and network performance evolution is in the hands of a few.

Opening Up the Possibilities

In contrast, a 5G New Radio (NR) network based on an O-RAN structure is constructed with hardware and software from many different vendors. For the hardware and software to work together, networks require a set of standards for all vendors to meet, including component performance requirements for the network's electrical, mechanical, and environmental operating limits, such as amplifier gain stability with temperature for specified frequency, temperature, and humidity ranges. Compared to closed RAN approaches, O-RAN systems feature software-programmable functionality in which new features can be added by programming software rather than having to modify the operating system.

In a 5G network, the two operating domains are the RAN and the core network. The RAN is visible to users, consisting of tower-mounted antennas and connected base stations. The antennas may be interconnected to the base station by copper or fiber-optic cables, sending and receiving signals between users with their mobile devices and more robotic users, such as Internet of Things (IoT) devices. The base station contains the hardware and software necessary to transmit, receive, and process signals, including digitizing signals for interconnection to the internet.

The core network performs less visible functions, including authenticating a user's mobile device, making connections to public telephone switched networks, gaining access to the internet, and making handoffs of a mobile communications device as a user moves from one base station to the next.

Risks vs. Rewards of O-RAN Architecture

There are challenges in implementing a 5G O-RAN infrastructure. Achieving fully interoperable hardware, software, and interfaces from multiple vendors is a massive exercise in synchronization. The network must also meet high expectations for data security, reliability, and operating lifetimes (to minimize network maintenance requirements). Interoperability within the 5G network components does not always occur automatically and often requires creative and innovative engineering from a partner with experience in component interoperability.

Building 5G infrastructure with an O-RAN architecture, especially with a modular design approach and a multiple-vendor ecosystem of network equipment suppliers, offers network operators competitive cost benefits compared to closed systems based on proprietary hardware and software. It also provides the flexibility to add functionality to meet the needs of different markets for mobility access, data download and upload speeds, and latency.

For infrastructure equipment OEMs, O-RAN makes it possible to specialize in one technology and invest in maximizing the performance of that one part of the system, making entry easier for start-ups and other newer market entrants. Innovation thrives when the market isn't limited to those with the resources to develop a complete system.

The O-RAN Alliance and the Open RAN Policy Coalition are organizations formed by leading telecommunications companies to support the adoption of O-RAN architectures in 5G NR networks. Such organizations define interfaces with O-RAN and enable custom features as needed, such as specialized enterprise (business) applications.

Designing for Higher Frequencies

Because 5G NR networks will have more users accessing high-data use applications than previous wireless network generations, they will require more bandwidth than before. That bandwidth comes from a mmWave range spectrum of about 24 to 52 GHz, providing higher data rates and lower latency.

Engineers faced with developing energy-efficient 5G base stations must now cover a broader frequency spectrum than ever before, at mmWave frequencies previously unused in commercial applications. In an O-RAN approach, the best technology that gets to market quickly can win significant market share. But developing and manufacturing mmWave products presents many technical pitfalls, from the interoperability of the "open" mmWave components to manufacturability and process development for challenging mmWave systems.

Supporting the Next Generation of 5G

Benchmark's engineering services leverage years of design experience to help system designers achieve 5G NR interoperability with mmWave and lower-frequency components. The design support extends from hardware components to embedded software to help speed the successful design and implementation of 5G NR base stations and infrastructure in an O-RAN environment.

Benchmark Lark Technology has developed a range of fully customizable RF filters extending to 40 GHz, including designs that offer significant size, weight, and power consumption advantages. We've been developing manufacturing and test processes for mmWave products for years, with the ability to troubleshoot production shortcomings and develop solutions that keep production on track to let you win on a level O-RAN playing field.

LyBio:

Hank Ly is a Business Development Executive for Benchmark serving the next-gen telecommunications and high-performance computing sector for the past six years. He helps identify the optimal service offering to match a customer's current and future product roadmaps. His major focus area is connectivity products.

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