Best Practices to Deliver on Its Promise —
It’s widely anticipated that the scale of 5G will eclipse all previous mobile technologies. Yet as the technology develops, the complexity of the 5G life cycle grows exponentially. The myriad 5G use cases all running on the same network — from enhanced mobile broadband (eMBB) to ultra-reliable low latency and the Internet of Things (IoT) — demand every nodal component of the 5G network to evolve.
In virtually all cases, communication service providers (CSPs) will be faced with planning, deploying, and managing ,their new 5G networks while also maintaining current 4G networks. As if the technology challenge of scaling 5G service deployment was not daunting enough, CSPs also have to prioritize key performance indicators (KPIs), CapEx, and OpEx.
Accomplishing these lofty goals requires a solid plan for validation, verification, and visibility into the 5G network to assure the performance of new services and command the 5G network.
Radio Growth: Compounding Pressures
Almost half of respondents in a recent end-user survey said that the top use case for 5G eMBB (Enhanced Mobile Broadband) is to achieve lightning-fast browsing. Likewise, more than a third of respondents identified their top use case as the ability to download content 10 times faster.
To truly deliver on the eMBB use case, large chunks of radio frequency (RF) spectrum are needed. For FR1 band, limited RF spectrum is available, but FR1 offers a much better coverage profile. FR2 band, on the other hand, has a significant amount of spectrum that can offer true eMBB experience.
Unfortunately, coverage in FR2 bands is extremely limited compared to FR1, which indicates the need to deploy a significant number of sites. While many service providers will use a hybrid deployment approach, in which FR1 is used for 5G coverage, and FR2 sites provide gigabit throughput, eMBB will require a significant increase in the number of radios deployed as well.
As CSPs build out dense 5G networks made up of small cell deployments, the potential for RF interference will grow exponentially, increasing the importance of optimized spectrum efficiency. Real-time spectrum analysis in the field will be key to identifying and addressing interference sources, enabling large-scale site deployment.
Moreover, 5G New Radio (NR) introduces flexible spectrum usage that relies on dynamic TDD and adaptive antenna system (AAS) technologies such as massive MIMO and beamforming. The use of these technologies means that evaluating radio performance can no longer be separated from antenna performance, necessitating over the air testing and 5G beam analysis techniques. Prior to service activation, field technicians will need to identify the signal at beam level and test the performance of all algorithms and handoffs, while also validating the signal to interference ratio, in order to validate 5G radio access network performance.
Transport Infrastructure: Changes and Choices
Transport — including backhaul, midhaul, and fronthaul (or xhaul) — creates a number of challenges in 5G. This is particularly true with more fiber going to the top of the tower, and new ultra-reliable low latency communications (URLLC)-based applications driving a much more flexible and agile fronthaul.
From a fronthaul perspective, common public radio interface (CPRI) is the most prevalent technology, providing a dedicated synchronous transport protocol specifically designed to transport radio waveforms between the remote radios and the base band unit. CPRI frames expand with the increase of radio channel bandwidth and the number of antenna elements.
However, CPRI is not very efficient in terms of statistical multiplexing, and cannot scale to the demands of 5G, especially for massive MIMO and larger bandwidth increments.
eCPRI, which is the evolution of CPRI, is packet-based technology. While it solves many bit rate and fronthaul capacity issues, it has its own challenges in terms of latency and synchronization.
One option is to use a fronthaul transport network node (FTN) to manage the ethernet access ring that can deliver a converged fronthaul supporting both legacy CPRI and 5G eCPRI. The challenge is to ensure that the radios are all in synch to avoid excessive delays and interference, otherwise devices will have trouble demodulating the signals and users will experience more dropped calls. This can be accomplished by validating FTN performance, while also running eCPRI tests to measure throughput, delay, and packet jitter.
With the right testing solutions, engineers can configure eCPRI message types according to specification, measure bandwidth for each message type and measure round trip delay (RTD). FTN tests enable engineers to validate the delay and synchronization requirements for the FTN, and can ensure it is within the designed network specifications. This test also can be used in the field to validate the fronthaul network performance.
Another key consideration is the increased need for fiber in more places to meet the massive number of small cells needed for 5G buildout. Assuring the performance of your 5G network requires testing of all components, connections, and the overall fiber network integration. After ensuring all physical layer tests are completed, including fiber inspection and certification, it is important to run higher layer tests along with timing and sync to ensure the best return on investment. Failure to properly test can not only cause network launch delays, but also leads to poor 5G system performance and unplanned capital expenditures, impacting customer experience and return on investment.
Test Automation: Scale 5G With Confidence
The increased complexity of 5G means that technicians need to look beyond just optimizing each individual cell site and focus on optimizing a cluster of sites that contain a variety of radio access technologies. The number of parameters involved in the 5G architecture are much greater than with past generations, driving the need for automated processes and procedures for test and assurance.
In an ideal world, all installations are flawless, and construction and commissioning are plug-and-play with no need to test any network components or the cables that connect them.
However, in the real world, we routinely encounter:
• Components that are defective or damaged during the installation process.
• Installers who lack adequate training and/or experience.
• Pressure to meet unrealistic daily quotas, which induces human errors, drives teams to take shortcuts or, in some cases, results in teams skipping testing altogether.
• Overwhelmingly complex deployment processes that are nearly impossible to execute flawlessly.
Yet, CSPs cannot afford repeat site visits after installation, necessitating greater test process automation to efficiently scale evolving 5G networks. With a focus on efficient, automated testing and optimization, service providers and contractors can overcome time-to-market and network quality issues, achieving scale and growth through consistent, repeatable, and streamlined, test process automation.
Additionally, by implementing automation throughout the life cycle — from lab test to cell site turn up, through to service assurance and optimization — CSPs can also benefit from predictive analytics. The use of monitoring and assurance solutions that leverage machine learning to predict future network issues and pinpoint failures enables mission-critical services to be delivered both reliably and cost-effectively, while generating the kind of insights needed to fully deliver on the promise of 5G.
“Top use cases for 5G enhanced mobile broadband (eMBB) in 2019 and beyond”. Statista. https://www.statista.com/statistics/867967/5g-embb-use-cases/