abril 8, 2021

Disaggregating the RAN: Everything You Need to Know About Open RAN and Optical Transceivers

Open RAN

When it comes to 5G and Radio Access Networks (RAN), the pushback against vendor lock has never been stronger. Vendor lock – for years, we’ve been helping customers all around the world get past it. Not too long ago, we wrote about the Fear, Uncertainty and Doubt (FUD) tactics that big-name NEMs use to keep network operators cemented to often overpriced, proprietary hardware and software solutions.

Thanks to groups like the Telecom Infra Project (TIP), the O-RAN Alliance, the Small Cell Forum, the O-RAN Software Community, and the Open RAN Policy Coalition, a new world of opportunity is dawning for network operators. Being stuck with one vendor’s proprietary hardware and software is no longer a given. Now, MSOs and MNOs have more choice and flexibility in creating the custom RAN solutions tailored to meet their specific requirements.

The challenge of navigating the increasingly diverse open RAN market centers around questions of increased system complexity, equipment interoperability and support. In this blog, we take a look at the benefits of open RAN, the challenges of pursuing open RAN architectures, and the need for an optical transceiver partner that can act as a glue to help network operators tie their hardware/software choices together.

A Quick Refresher on 5G Open RAN

The journey to 5G open RAN has been a long time in the making. As SDxCentral notes, “Open RAN standards…aim to undo the siloed nature of the RAN market, where a handful of RAN vendors only offer equipment and software that is totally proprietary.” Current 5G open RAN builds upon earlier, gradual moves (Cloud RAN, Virtual RAN) to open up the RAN (hardware, software, interfaces) to Commercial Off the Shelf (COTS) equipment and vendor-neutral software-defined technologies.

Previous RAN architectures generally exhibit a Remote Radio Unit (RRU) on a base station that leverages either proprietary or COTS-based hardware. This equipment is connected via proprietary interfaces to a Baseband Unit (BBU). In a conventional Cloud RAN (CRAN) design, the BBU is located away from the actual radios, in a data center. In a Virtual RAN (vRAN) architecture, the proprietary BBU hardware gets replaced by a COTS server. However, the interfaces between the BBU and RRU are still proprietary in vRAN. This means that network operators are still forced to use a vendor’s proprietary software to virtualize RAN functions on the COTS servers. The backhaul portion of the network connects the BBU to the core.

Modern 5G Open RAN designs take this disaggregation to the next level by opening the RAN into three main components. Instead of RRUs and BBUs, the network architecture centers around a Radio Unit (RU/RRU), a Distributed Unit (DU) and a Centralized Unit (CU). The fronthaul connection thus exists between the RU and DU, while the link between the DU and CU is characterized as midhaul. The network connection between the CU and the core thus becomes the new backhaul environment.

Advantages and Challenges of Open RAN Architecture

Put simply, entering the open RAN market offers network operators much more flexibility in terms of designing an exact solution that meets their particular requirements. Network operators are no longer resigned to sticking with a vendor whose technology path does not align with their own goals. Having industry-wide standards to support equipment and software interoperability also encourages new vendors to enter the market. In turn, this creates even more choice and potentially more affordability for network operators. With new standards in development, the open RAN ecosystem will make deploying 5G RANs more efficient as well as power better performance through the implementation of machine learning and artificial intelligence.

In practice, however, the disaggregated open RAN market is still in the beginning stages and, as such, creates certain pain points for interested network operators. As SDxCentral points out, Rakuten’s LTE RAN in Japan is currently the world’s only large-scale RAN that leverages open RAN technology. While MSOs and MNOs excel at operating some of the world’s most premier networks, building an optimal open RAN network can become complex, quickly. Integrating new hardware and virtual network functions (VNFs) into existing network architectures is a time-intensive process. In the event of network issues or problems, network operators could also find themselves hard-pressed to identify which product is malfunctioning. As a result, partnering with the right vendors is critical for operators to acquire both the solution they want and the ongoing support they need.

Precision OT As the Glue

At Precision OT, we’re specialists in optical transceivers. At first glance, you might be wondering how this ties into your open RAN goals. The answer is that, in our experience working with some of the world’s leading network operators, it can be easy to overlook the vital role transceivers play in bringing all the different components of your RANs together. Before CRAN, vRAN and open RAN, network operators partnered with one vendor that would supply them with all the necessary building blocks and even help put them together. Now, however, operators are moving away from the single vendor approach as their needs become more specific and niche. The sector is increasingly embracing a disaggregated network made up of components from multiple vendors.

Here’s one example of how optical transceivers influence the open RAN architecture. In a recent article in Lightwave, our CTO, Chris Page, talked about 5G fronthaul and the gradual shift from 10G to 25G enhanced CPRI (eCPRI). As a quick reminder, eCPRI improves upon the proprietary CPRI standard by opening up the interface between the RU and DU – an integral part of the open RAN paradigm. The point is that transceivers are critical in ensuring that your RAN operates as seamlessly and optimally as possible across fronthaul, mid haul and backhaul. Finding the right optical equipment manufacturer can make all the difference in ensuring the success of your open RAN design and rollout.

That’s where we come in. Partnering with us is about more than just selecting the right transceivers for the job. Our whole raison d’etre is to share our engineering expertise with our customers as they build the RANs they want. We’re a team of network engineers first. In fact, thanks to our laboratory, our team members can replicate your network conditions and test our products to ensure we are creating the solutions that will work for your needs. Precision OT is also a member of both TIP and the O-RAN Alliance. Whether you’re building an entirely new open RAN architecture or struggling with issues around interoperability and integrations, we can help.

Learn more about us by reaching out with your questions!

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