5G beamforming a critical technology for fixed wireless and mobility
Testing beamforming is tricky but crucial, because the technology introduces a level of complexity on both the infrastructure side and the device side that demands careful characterization and verification before 5G can be successfully deployed.
“Every country wants to say, we are the first country in the world enabling real 5G. That goes down to the operators who are putting pressure on themselves and infrastructure vendors, and in the end all of this pressure is accumulating on the shoulders of the chipset vendors – because they are the first ones in the chain to be required to deliver stable solutions,” said Benoît Derat, senior director of development for EMC, OTA and antenna test systems at Rohde & Schwarz.
The challenges of testing beamforming are being reflected in test equipment. The number of channels that need to be tested at the chipset level for base station equipment is increasing, for instance, and each one must be characterized over frequency and for levels of accuracy in phase adjustment and level adjustment, according to Markus Lörner, market segment manager for RF and microwave components, who focuses on conducted testing.
As it’s shaping up, consumers — at least in the early days, will likely pay a premium for 5G service. And when you’re paying a premium for a service, you expect to be provided with a premium service, which highlights the need for operators and their partner ecosystem to exhaustively validate the performance of 5G systems including beamforming.
Speaking about his experience working with operators deploying fixed wireless 5G, Viavi’s Kashif Hussain, director of solutions marketing, explained this process starts in the lab before the first piece of equipment gets activated in the field. “Before they launch, they want to make sure the beams are working as designed,” he said. “They are looking at the aggregation aspect of it meaning, in a sense, the different beams and reading the [synchronization signaling block]off of them. These beams are associated with that particular [physical cell ID].”
This is where Viavi brings in its TM500 and CellAdvisor 5G products. Engineers can simulate a loaded network environment and test the quality of real-word user experience. TM500 simulates user equipment connected to varying gNodeB configurations (spectrum bands and sub-carrier spacing for a channel up to 100 megahertz), including millimeter wave frequencies and massive MIMO transmissions. CellAdvisor 5G helps validate the RF environment and lets engineers see downlink anomalies ranging from power and modulation to cabling/antenna problems and beamforming.
“Today they have no other mechanism truly to validate, even with a scanner, they are not getting the SSB details we’re offering in our solution,” Hussain said. “If there’s beam that’s not working correctly because of any hardware anomalies, we can see that.” Based on real-world testing experience, he said one of the problems identified was a problem with the device itself.
To learn more about 5G beamforming, the test and measurement considerations, and how operators are using the technology, download this report.