Transport priorities for the next phase of 5G

After passing the 1 billion subscriber mark in 2022, 5G is moving toward its next phase: 5G-Advanced. As the transport network evolves to support 5G-Advanced, capacity will remain the prime focus. However, other factors will also rise in prominence, including packetization, RAN virtualization support and, increasingly, white box.

In February, Heavy Reading conducted the fourth iteration of its annual 5G Transport Market Leadership Survey with project partners Ericsson, Fujitsu and Nokia. The 2023 survey attracted 87 qualified network operator responses from around the world who shared their views on transport deployment issues and timelines, fronthaul networks and RAN centralization, routing and synchronization, and 5G edge connectivity.

This blog is the first installment in the three-part series highlighting the key findings from the study. It focuses on virtualization, trends in white box and capacity plans.

Cloudy future for the RAN

Cloud RAN (or virtualized RAN, vRAN) tops the list of priority initiatives network operators expect to implement in the next three years, with 59% of operators surveyed expecting to implement RAN virtualization by 2025. Comparing survey results from year to year, vRAN is gaining steady momentum. Operators want the service flexibility that a vRAN architecture provides, and virtualization technology has matured. While initially tightly coupled with centralized RAN (C-RAN) architectures, virtualization in traditional distributed RANs has become more popular over the past two years.

Regarding where centralized and/or distributed unit (CU and/or DU) virtualization is deployed, however, the industry lacks consensus. Cell sites, local hub sites and edge data centers are all in play in 2023. By 2025, operators surveyed expect the biggest uptick to occur in edge data center locations. Heavy Reading believes the uptick reflects the anticipated maturation of operators’ edge strategies, which are still nascent in 2023.

Which of the following is your organization currently implementing or planning to implement by 2025?

(Source: Heavy Reading)

White box heats up

In the white box procurement model, the network operating system is separate from the underlying hardware, with each supplied by different vendors. In transport networks, these white box elements can be routers, packet-optical equipment or DWDM transponders. Heavy Reading has been tracking white box transport for several years, and, like vRAN, white box continues to gain momentum in 5G — across all network segments.

Operators surveyed expect white box elements to have their highest deployments in cell sites and aggregation nodes. 44% of operators expect high deployments in cell sites (defined as greater than 50% of total elements), followed closely by aggregation, with 41% expecting high deployments.

Among the top benefits of white box cell site and aggregation deployments are easy integration into the RAN, compact footprint where space is at a premium and scaling from 10G to 400G on the same platform.

How extensively does your organization expect to deploy white box optical transport platforms over the next three years for the following 5G transport segments?

(Source: Heavy Reading)

100G and beyond

5G marks a big step up in capacity per cell site, with 10Gbps replacing 1Gbps as the standard for per cell site connectivity in backhaul. This tenfold jump in capacity is needed to meet initial 5G cell site requirements, as well as to provide room to grow for future increases. But the impact on 5G transport segments goes well beyond 10G, based on Heavy Reading survey results. Just over two-thirds of operators expect at least 100Gbps of capacity will be required in backhaul (67%) and aggregation (68%), while just under two-thirds of respondents (59%) expect that greater than 100Gbps will be needed in edge access.

While 10Gbps to the individual cell site will be sufficient, operators will often carry traffic from multiple cell sites, such as when using ring topologies for backhaul or when aggregating traffic coming in from multiple cell site locations. These survey results provide strong support that 100Gbps and even 400Gbps will play major roles in edge, aggregation and backhaul networks over the medium term.

What is your average expected bandwidth capacity in each of the following segments over the next three years (i.e., end of 2025)?

(Source: Heavy Reading)

Lastly, operators have many technology options at their disposal, including transponder-based WDM xHaul, packet xHaul, cell site routers (with no CPRI) and cell site gateways (with CPRI-to-eCPRI conversion). The survey results indicate a broad mix of technology adoption with no clear winner. Rather, like with many technology introductions, operators will go for a “tools in the toolbox” approach and pick the best option for each job.