How to build a 5G test strategy

Ensuring quality and device performance while controlling cost and complexity

5G is growing in popularity due to rapidly expanding consumer and enterprise demand for more bandwidth. The future growth of 5G is predicated on enterprise and consumer use cases which have different requirements of data, latency, reliability, and capacity. Developing an appropriate test and validation strategy to ready products for 5G requires a different approach, asserts Khushboo Kalyani, senior product marketing engineer at Litepoint.

Litepoint makes test solutions for wireless modules and consumer electronics, including 5G. To be successful, she said, companies must ensure quality and device performance, but control cost and complexity.

5G test strategy challenges are considerable, she said. “The addition of newer bands, spectral efficiency techniques… even though these like sound great options and seem favorable, it significantly increases the device complexity and adds test challenges from a product development point of view.”

Outlining the challenges

Kalyani offered a practical example: 5G complicates the device’s radio frequency (RF) front end design, requiring unique and separate RF chains to support more bands and bandwidths.

“There is a low harmonization of spectrum in the world,” said Kalyani. “So the same hardware will be expected to support multiple different bands.”

The addition of new multiple-input multiple-output (MIMO) antennas also increases the complexity of a 5G test strategy, she said.

“It increases the antenna count in the devices, because now you need to support higher-order modulation MIMO schemes, and then multiple different frequencies,” she said.

This drives significant test considerations, starting with RF parametric testing to calibrate and verify across bands and bandwidths.

“Wider bandwidths could cause adjacent channel leakage and interference,” she explained.

5G requires new tests for antenna performance and tuning, hardware device functional verification, application-level throughout testing with MIMO, and user experience testing, she explained.

“The first test challenge is the increased test case count,” she said. As 5G device proliferation continues globally, many test cases will need to be designed, scripted, and developed to verify “myriad possible combinations of bands and bandwidths.”

To address this, Kalyani recommends leaning on software automation. This helps aid the running of hardware and software regression across critical metrics and help curb test time.

“Optimizing the tests to run for manufacturing would save test time,” she said.

The second challenge, she said, is the finite number of tester ports and resources. That means buying new test equipment or upgrading it.

“The rising device antenna count and support for sub-6 GHz and millimeter wave (mmWave), and the higher order of 8 × 8 MIMO requires that the tester port density be higher for conducting testing,” Kalyani said.

Using an external RF port expander increases tester port density and enables reuse capacity. “Since the device port antenna count is increasing, adding an additional RF port expander that enables the reuse of the same test equipment would save a lot of operational and investment cost,” she said.

Kalyani also recommended choosing a companion tester with more vector signal analysis and generation (VSA / VSG) pairs. This will reduce multi-device test times, she said.

Modules, packaged together with other modules – such as Wi-Fi, GPS, Bluetooth and more – can create interference and coexistence problems which will degrade performance.

“Other methods would have to be added to test the product’s performance,” she explained.

To that end, Kalyani offered signaling test as a way to make sure everything’s working as intended.

“A signaling test will actually aid in validating product performance in its entirety,” she said. “We recommend to examine the vitals of the finished product to warrant basic user functionality and minimize returns from the field. Signaling tests must be incorporated in sampling or manufacturing. “