As operators worldwide deploy 5G networks, the transition from 4G to 5G is generating growth in the test and measurement space for radio frequency (RF) technologies.
In fact, recent research suggests that the RF test equipment market will be worth $3.7 billion by 2025, representing a compound annual growth rate (CAGR) of more than five percent.Advancements in radio technology are key to achieving the 5G vision.
However, deploying and supporting complex 5G network architectures is not a simple endeavor. The 5G new radio (NR) standard introduces flexible spectrum usage with scalable numerology, dynamic time-division duplexing (TDD), massive multiple input multiple output (M-MIMO) and beamforming — all of which will create greater challenges in the field for RF engineers to validate, test and optimize the 5G network.
Moreover, while visibility of the radio is important in a 5G mobile assurance and optimization system, it’s only part of the story. 5G networks involve more components than previous generations – including network functions in the radio access network (RAN) and core, transport, backhaul, midhaul and fronthaul. In addition, with Multi-access Edge Computing (MEC) and Ultra-reliable Low Latency Communication (URLLC), the RAN is becoming the new core with more intelligence moving to the network edge. Thus, a complete system is needed to facilitate the detection and identification of root causes for failures, impairments, congestion and other issues in any of the components.
To achieve this requires greater visibility for insight into all aspects of the network, including the demand or load on the network, the state of the network configuration and impairments in all the components, and the response of the network in terms of performance. Additionally, the detection, root-cause analysis and resolution of problems requires that all factors are correlated for proper testing. What’s more, operators will be looking at trends in terms of how a network is behaving over time.
Impact of M-MIMO, Beamforming
5G networks will have much greater capacity and improved resiliency through M-MIMO and beamforming. By focusing the transmitted energy of beams more strategically, spatial variations in RF will become more granular.
The nature of M-MIMO and the separation of the radio into beams translates into radio characteristics that vary significantly over ever shorter distances. As such, it’s vital for operators to determine the suitability of an environment for M-MIMO. A number of factors will determine the appropriate degree of M-MIMO, including the type of deployment, environmental dynamics and how well the beam lock is maintained. As such, operators will need to understand the performance of the radio down to the resolution of individual beams and inter-beam management.
In addition, the benefits of M-MIMO will vary with environmental conditions, and these conditions must be understood as operators determine where to deploy and optimize M-MIMO. As such, the ability to manage cells and their neighbor relationships will give way to managing the way beams interact, with the overall goal of ensuring that inter-beam mobility operates seamlessly with intra-cell, inter-cell, inter-carrier and inter-technology mobility. 5G operators will need to determine how these mechanisms are performing, and they’ll need performance metrics down to highly granular location accuracy to troubleshoot and resolve issues. This is a big change for the industry moving from a cell-centric world to a beam-centric world.
5G networks also depend upon complex conformance testing for devices and base stations before they’re released to the marketplace. Conformance tests are important for developing a baseline of functionality in user equipment (UE) and base stations, as well as validating transmitter and receiver characteristics and performance. Radio resource management (RMM) and protocol testing are needed for devices, while RF parameters are used as a baseline to test base stations.
Meanwhile, conformance testing for UEs depends upon radio access, demodulation and signaling tests, as well as validation by certification organizations to ensure they comply to the latest 3GPP specifications.
Impact on QoE
A key factor to consider when testing 5G is how to assure quality of experience (QoE) for the end user. Unlike with previous generations, however, the end users on 5G networks also will include a significant number of machines in addition to humans. As such, current methodologies for testing and measuring voice, video and data quality to end users needs to be expanded to include massive machine-type communications (mMTC)).
The International Telecommunication Union (ITU) has identified three primary use cases for international mobile telecommunications 2020 (IMT-2020): enhanced mobile broadband (eMBB), URLLC and mMTC. Each of these use cases demands different ways of measuring QoE, especially in the RAN. This fuels the need for expanded test methodologies that incorporate new parameters with higher frequencies and wider bandwidths. With a beam-centric environment encompassing 3D, Location Intelligence will be even more important, providing granular insight into the RAN, subscribers and services coupled with App-aware data.
As 5G networks grow to support applications like connected cars, network performance will become absolutely crucial. Delay, jitter and other network issues could result in disastrous results, meaning 5G QoE testing needs to be verifiably traced and transparent to certified international standards bodies, as opposed to proprietary network equipment manufacturer (NEM) specifications or techniques.
5G RF Network Performance
The primary use cases for 5G RF network performance management build on those for existing 4G networks, including:
- The ability to enumerate best beam identification with geolocated mapping of users and events to aid problem drill-down
- Optimization of network configuration with consideration given to both the geographic distribution of subscribers and traffic demand.
- Identification of poorly performing UEs with the ability to drill down to identify root cause issues
- Automation of subscriber-centric optimization.
Effective mobile assurance and optimization solutions must amplify the ability of a network engineer to visually assess these use factors to determine when an issue should be escalated, as well as to drive automation in networks. This is extremely important for 5G networks, which incorporate additional dimensions of configuration and adaptability through features like full dimension MIMO (FD-MIMO) and network slicing.
For example, over-shoot and interference issues can now be addressed in more powerful and subtle ways because FD-MIMO can set an effective tilt-profile for individual subscribers vs. a single value of tilt for all users in a cell. Likewise, network slicing and segregation of resources becomes more valuable when analysis is based on distribution of subscribers, subscriber classes and associated demands per slice.
Without question, operators will benefit tremendously from 5G networks that support a new breed of services across virtually all verticals. Yet to do so, 5G networks must provide mobile assurance, geolocation and optimization systems from the outset. Mobile assurance solutions for 4G and older technologies must be fit for rapid evolution to 5G, with flexible deployment in the end-to-end network that enables them to respond to the physical location of functional splits, thus ensuring support for 5G non-standalone (NSA) and standalone (SA) networks, along with coexistence with 4G infrastructure.
By implementing robust testing procedures along with mobile assurance, geolocation and optimization solutions, operators will ensure rich user experiences and create new service opportunities for any 5G architecture evolution.
About the Author
Paul Gowans, Wireless Strategy Director for VIAVI Solutions, has more than 25 years’ experience in the communications and wireless industries with expertise in IP, Mobile, VoLTE, Virtualization and Analytics.