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5G

5G transport: Putting networks to the test

As 2020 marches on, it is clear that 5G is not sitting still. The long-awaited 3GPP Release 16 freeze occurred in July, just a couple months off schedule due to COVID-19. With limited delays caused by the pandemic, the 5G commercial launch schedule continues largely as predicted. Omdia's latest forecast, published in June, projects that the top 20 global markets will reach 231 million 5G subscribers by year-end – a 15x increase over 2019.

In order to understand how transport networks will evolve to support 5G services, Heavy Reading launched the Operator Strategies for 5G Transport Market Leadership Study with collaboration partners Anritsu, Ericsson, Fujitsu and Infinera in May 2020. The survey attracted 86 qualified network operator respondents from around the world that shared their views on transport deployment issues and timelines, fronthaul networks and radio access network (RAN) centralization, routing and synchronization, and testing 5G networks.

This blog, the third in a four-part series highlighting the key findings from the 2020 study, focuses on testing implications for 5G networks.

Interoperability in an open RAN
One of the fundamental differentiators and benefits of 5G architectures compared to previous mobile generations is the decomposition of the RAN into functional components. These include antenna units (AUs), radio units (RUs), distributed units (DUs) and centralized units (CUs) with the corresponding connectivity segments of fronthaul (RU to DU), midhaul (DU to CU) and backhaul (CU to mobile core). One operator benefit is that greater flexibility drives greater coordination and efficiencies in the RAN. Another benefit is the prospect of an open RAN comprised of functional components supplied by different radio vendors — including new entrants.

Looking at the trend in opening the RAN, Heavy Reading wanted to better understand how operators seek to ensure interoperability among the various RAN components. Specifically, the survey asked: "For your organization, what are the most important testing methods to ensure interoperability in an open RAN environment, such as defined by the O-RAN Alliance and Telecom Infra Project (TIP)?"

Most important testing methods in open RAN environments
n=85
(Source: Heavy Reading)
n=85
(Source: Heavy Reading)

In the rankings, two methods rose to the top. Operations, administration and maintenance (OA&M)-enabled remote network monitoring tools ranked first (selected by 45% of respondents) and was followed by third-party cloud-based or network functions virtualization (NFV) test utilities (selected by 40%). The remote and cloud-based testing ranked above both vendor equipment built-in tools (selected by 34%) and field portable tools (selected by 31%). Results indicate that operators want remote testing abilities when possible.

Measuring fronthaul performance
As noted in previous analysis, the centralization of the RAN and the creation of the new fronthaul transport segment pose particular challenges for operators. These are due to greater bandwidth requirements combined with stringent performance requirements relative to other transport segments.

The fronthaul networks pose challenges for operators from a testing perspective, as well. Heavy Reading asked operators to rank next-generation fronthaul performance requirements on a scale of 1 to 5, with 1 being the most challenging and 5 being the least challenging. Weighted scores were generated based on assigned priority.

With weighted scores of 264 and 263, respectively, packet-based latency measurement verification for ultra-reliable low latency communications (URLLC) applications and packet-based bandwidth throughput verification for enhanced mobile broadband (eMBB) applications were essentially tied at the top of the performance requirement challenges list. Tied for third (with equal weighted scored of 214) were packet-based traffic priority and profiled verification for network slicing and packet-based timing/synchronization verification for 5G. At a distant fifth position, and the least challenging, was packet-based eCPRI/O-RAN 7.2x functional split verification.

Most challenging performance requirements for next-gen fronthaul networks
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Note: The score is calculated by assigning a weight to each rating where the highest priority rating holds the highest weight.
(Source: Heavy Reading)
n=76
Note: The score is calculated by assigning a weight to each rating where the highest priority rating holds the highest weight.
(Source: Heavy Reading)

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— Sterling Perrin, Senior Principal Analyst – Optical Networking & Transport, Heavy Reading

This blog is sponsored by Anritsu.

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