Lessons from the first wave of 5G deployments - Why transport is critical to 5G rollout

Over the past 12+ months, Ericsson has deployed tens of thousands of 5G radios with our customers in North America. The deployment has been both on macro sites and small cell sites like utility poles and street furniture. Along the way, we have seen first-hand the challenges that come with getting sites on air, on time and on budget. Below are some of the lessons learned around how the transport network can either enhance or impede the 5G build.

Street macro

Principal Solution Manager, 5G

Principal Solution Manager, 5G

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5G for existing sites

When 5G is added to existing sites (which is a significant portion of the first round of deployments), the challenge is twofold. First, while having existing infrastructure helps because sites are already equipped with utilities like power and transport, we found that the transport capabilities often cannot support the added 5G throughputs. The fiber capacity of the last leg to the site is especially critical. If capacity is not available in a timely manner, deployment schedules are at risk. We have seen a big increase in demand for dense wavelength division multiplexing (DWDM) solutions to increase utilization of the existing fibers. Having these options has proven critical in meeting deployment timelines for successful 5G rollouts.

Second, footprint has been an important variable to consider, as space and power on sites have become scarce resources. When adding DWDM to existing sites to stretch fiber resources, the equipment must be flexible. In our experience, equipment must be designed for a large variety of use cases–indoor and outdoor, simple and complex, compact, subterranean, and so on. At times, the only place for the DWDM equipment is either mounted behind the radio or in a hole under the site. For this reason, Ericsson has been working very closely with customers to address the range of deployment scenarios. To meet the deployment challenges, we have customized a range of DWDM solutions–we have even designed equipment to go into a manhole!

With various options to help constrained fiber meet the deployment need, service providers can keep to their schedule. This has been a game changer for some of our customers.

New 5G sites

What about new sites? As we move into the second phase of 5G rollouts, we will see increasing demand for new street level sites. While fiber is often an option, it can be either prohibitively expensive, or take too much time to build, pushing schedules way out. E-band microwave provides the capacity, flexibility and reach that make it a great option, especially since it can support up to 10Gbps per carrier. We have seen operators use E-band both as a quick fix to get a site on air while fiber is built and as a long-term solution for the site. We predict that E-band will become a bigger factor as operators push to keep up with rollout plans.

Architecture variants

Another key learning over the past year has been that the variety of architectures is increasing. In previous generational upgrades, Distributed RAN (DRAN) has been ubiquitous. While the backhaul often needed to be expanded for the new G, it was relatively straightforward.

5G is definitely changing that game. Beefing up the backhaul is not what it used to be. Disaggregation and virtualization have given rise to new RAN architectures like Centralized RAN (C-RAN) and Elastic RAN (E-RAN) putting new requirements on the transport network. All of these architectures have new interfaces, with different latency and capacity requirements. Transport solutions, both fiber and microwave, need to address both fronthaul and backhaul, supporting C-RAN, E-RAN and D-RAN. Equipment must support the required capacity and carry CPRI, eCRPI, or any standard Ethernet application. Cell site routers need high capacity interfaces. And the transport network must be designed to support tighter timing and synchronization requirements demanded by TDD spectrum and advanced RAN capabilities.

In the trenches

Over the last year, Ericsson deployment teams have been ‘in the trenches’ with our customers deploying 5G. The first wave has been tough, stretching existing fiber capacity to the limit, and signaling the need for new solutions. The variety of deployment situations we have seen–from street poles to traditional sites, have pushed us to develop new solutions as well.

The next wave will be even tougher as we build out the small-cell layers needed to increase 5G footprints.

It’s no longer good enough to do the RF plan, deploy radios and plan on adding capacity to the backhaul. Transport needs to be an integral part of the 5G deployment plan to minimize delays and performance degradation while the transport network catches up.

Learn more about Ericsson transport solutions here.

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