During the Rohde & Schwarz webinar, “How Network Testing Ensures 5G Private Network Performance,” Arnd Sibila, Rohde & Schwarz Technology Marketing Manager, discussed the tests that must be completed between the network deployment and when it is ready for the customer. And Christian Müller, Rohde & Schwarz Senior Business Development Manager, demonstrated how to use the equipment to get practical measurements.
Sibila discussed the implications for test measurement vendors as private 5G use cases become more interactive in real time and services become more critical to the operation of enterprises. Future service level agreements may demand six-nines reliability or a downtime no more than 31 seconds in one year.
“We see that the quality requirements differ between different use cases,” Sibila said. “It’s completely different whether you have a use case with relaxed requirements in terms of latency, or a use case with very strict requirements for latency, so that there is a wide field between these different requirements in quality.”
Sibila emphasized the trend from measuring the quality of experience (QoE) for human users, which is always on the application layer, to testing the quality of service (QoS), which is on the IP layer. “So that’s very important: testing the combination of the application-layer QoE and the IP-layer QoS,” he said.
The process for assessing the performance of a private 5G network consists of making sure the uplink spectrum is clear, passively testing the downlink, and actively testing system coverage and formal performance.
Step One
The initial focus of measuring a private 5G network is on the spectrum, testing the uplink to see if it is clear or if there is interference. This involves checking the frequency bands and identifying interferers. “Very important is the uplink spectrum performance and checking for interference,” Sibila said. “We need to see whether the spectrum is clear or whether we have any interference in the spectrum uplink.”
Step Two
Next, the passive tests are performed on the 5G downlink including all broadcast signal information, coverage measurements, signal quality measurement, and signal decoding. Functional testing is performed to measure the download, upload and Round-trip Time (in milliseconds) or the latency of the network performance.
Additionally, the network RF emissions must be tested to make sure they are below a certain threshold so that is not harmful in terms of health for humans.
“We also must test synchronization, because in 5G we are normally operating TDD [time division duplex] networks and it is very important that every access point is fully synchronized,” Sibila said.
Step Three
The third step measures coverage and formal system performance. It involves active tests, which require access to the network and look at signaling layer three messages, data tests, downlink test, uplink test, data throughput test and latency tests.
“The key here is to measure whether we see enough access points at every position,” Sibila said. “So do we have sufficient redundancy in terms of number of access points?” Continuous data collection is performed in the environment of the private network to gain real-time quality monitoring to identify long term trends in the performance of those networks.
Conclusion
The first two steps are only performed once unless there are issues with the network. Step three, commercial performance testing phase, is performed after every factory modification. “Because if you change the physical environment, like moving around metal shelves or whatever, you are basically changing the complete RF environment. And you have to basically check all these performance mechanisms’ key performance indicators again,” Sibila said.
While 5G technology enables many business-critical use cases, private 5G networks are still, mostly, in the experimental phase, according to Sibila. But, he notes, that will change.
“5G technology-enabled business critical use cases are a big, big thing now because we have a lot of WiFi in private networks that are not reliable enough for manufacturing or other processes. 5G technology will really go the next mile and basically fulfills the requirements for business-critical use cases,” he said.
Sibila said having sophisticated test solutions available is very important, because technicians need insights into network performance to ensure adequate capacity, low latency and to avoid downtime.
“We will have guaranteed service levels that we need to provide,” he said. “And this first of all is capacity, data throughput and latency. And the second very important part is high availability, high reliability,” he said. With proper testing, private 5G networks can be deployed and maintained to keep factory floors and other applications humming along.
By J. Sharpe Smith, Inside Towers Technology Editor
Reader Interactions