Tackling transport challenges ahead of 5G-Advanced

Plans for RAN virtualization and centralization are well underway, according to Heavy Reading's latest round of survey research. Still, there are some key challenges that directly affect the transport network. Operators will need to identify and resolve these transport issues to meet their ambitious rollout expectations.

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 second installment in the three-part series highlighting the key findings from the study. It focuses on trends in cloud RAN, centralized RAN (C-RAN) and microwave transport.

Cloud RAN challenges

As discussed in the previous blog, cloud RAN (or virtualized RAN, vRAN) tops the list of priority initiatives network operators expect to implement in the next three years — ahead of other big initiatives, including RAN centralization and network slicing. This ascendancy of virtualization represents a big change from years past. However, operators understand that vRAN implementation is not without its challenges — including issues affecting the transport network.

Among the challenges, nothing is more top of mind than security, which was picked as the biggest transport challenge by 57% of respondents. Other issues — including CPRI conversion, multi-vendor support, precise synchronization design, and operations, administration and management (OAM) — are all secondary to security and closely clustered in the 33–39% response range.

Heavy Reading did not ask about this explicitly, but virtualization with multi-vendor open RAN likely contributed to the security concerns expressed in the survey. Open RAN security is a major topic within operators, standards bodies and governments globally. But operators can virtualize functions independently of open RAN, and the earliest deployments do so.

What are the biggest transport challenges you foresee in supporting cloud/vRAN architecture in your network?

Figure 1:
(Source: Heavy Reading)

C-RAN expectations

Heavy Reading has been tracking steady progress on C-RAN architectures for several years. Just over half of operators in the 2023 survey (51%) are deploying C-RAN or plan to do so. For those planning C-RANs, just over three-quarters (77%) expect that more than 20% of RAN sites will implement centralization by year-end 2023, and nearly half (45%) expect that more than 40% of RAN sites will be centralized. These results confirm that following years of planning, C-RAN implementation is now well underway.

Naturally, expectations increase for 2025, but the predicted increases are not dramatic. By year-end 2025, 84% of operators surveyed expect more than 20% of RAN sites will have implemented centralization, and 57% expect C-RAN in more than 40% of sites.

What percentage of your organization's RAN sites will implement a centralized RAN (C-RAN) by year-end 2023? By 2025?

Figure 2:
(Source: Heavy Reading)

As with cloud RAN, challenges also exist for operators implementing C-RAN. Lack of space looms large as the primary challenge for C-RANs, as 55% of the survey group cited a lack of hub space for consolidated equipment. Operators have abundant central office (CO) space, but existing COs do not necessarily match up with ideal C-RAN hubs, which must be sited at central locations close to multiple cell towers.

Challenges such as lack of space and inadequate cooling/power/battery backup may become even more pronounced as RAN virtualization places servers in locations that are not data centers. Space, power and HVAC will all need to be reviewed for cloud RAN sites outside the data center.

A role for microwave transport

Fiber is the first choice for 5G xHaul, but it is not always physically available or financially feasible. In these cases, microwave transport is an option. More than half of operators surveyed (54%) have deployed or plan to deploy microwave transport for 5G, and Heavy Reading research consistently shows that microwave transport has an important role to play in 5G xHaul, across all geographies.

According to the 2023 survey, the primary driver for deploying microwave transport for 5G is time to market/fiber availability, which was ranked first on the list by nearly half (45%) of operator respondents. Second on the list was the high costs of leased fiber, the first choice of 28% of respondents. In other words, a lack of fiber availability and/or the high cost of obtaining fiber will continue to drive the microwave transport decision.

How important are the following motivations for deploying microwave transport in your 5G transport network? (Rank in order, where 1 = most important)

Figure 3:
(Source: Heavy Reading)

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This blog is sponsored by Ericsson.