A New Era of Upgraded T&M Equipment Helps Designers Vault 5G ChallengesMarch 12, 2020 by Gary Elinoff
Sure, traditional test and measurement equipment do the job. But a new class of T&M solutions may be the way forward in the 5G universe.
As 5G comes closer to reality, 5G designers face several obstacles in regard to test and measurement (T&M). In a paper from National Instruments, engineers designing and testing 5G devices faced a unique set of challenges.
The Challenges 5G Designers Face
For one, the waveforms are more complex, such as various types of orthogonal frequency-division multiplexing (OFDM). The below image illustrates a type of digital modulation in which digital data is encoded onto multiple carrier frequencies.
Digital modulation that enables digital data to be encoded onto multiple carrier frequencies. Image used courtesy of National Instruments
Another issue is the huge frequency ranges of 5G. Instruments generating and measuring these waveforms must perform linearly over frequencies ranging from hundreds of megahertz to tens of gigahertz.
National Instruments explains that instruments geared for 5G must be both wideband and linear. Image used courtesy of National Instruments
Component characterization is also more difficult because units must operate at super-high 5G frequencies as well as over lower legacy (2G, 3G, and 4G) bands.
5G designers must also work with MIMO or multiple-input-multiple-output technology; 5G beamforming systems introduces the complex necessity of spatially dependent measurements.
High-volume testing is also a burdensome factor considering the sheer volume of low-cost 5G components.
Companies Optimizing T&M for 5G
Although most existing test and measurement equipment will certainly be compatible with 5G devices, a few companies have gone above and beyond to optimize T&M tools for the new generation of wireless technology.
Renesas’ Wideband Millimeter-Wave Synthesizer
Renesas' new wideband millimeter-wave synthesizer, 8V97003, is built for 5G and broadband wireless. It can serve as a local oscillator for millimeter-wave beamforming and as a precision reference clock for high-speed data converters used for T&M functions.
The 8V97003 for 5G. Image used courtesy of Renesas
In addition to its efficacy in generating frequencies for test purposes when developing 5G devices, the 8V97003 also serves in end-product 5G devices.
“We developed our new 8V97003 for the latest generation of high-performance mmWave radios, ensuring it meets our customers’ most demanding frequency range, phase noise, and output power requirements,” said Bobby Matinpour, VP of timing products at Renesas' IoT and infrastructure business unit.
“With its best-in-class performance in a single-chip design, the 8V97003 is particularly well-suited for emerging applications above the 6 GHz carrier frequency, including broadband wireless, microwave backhaul, and 5G radios.”
As a synthesizer/phase lock loop (PLL), the 8V97003 operates from a VCO and generates outputs up 18 GHz with an octave’s tuning range. The unit’s 32-bit fractional feedback divider combined with its output divider allows for the full exploitation of the wideband capabilities of the VCO.
The unit offers a notably low output-to-output phase skew drift, measuring less than 10° across all frequencies and operating conditions. This serves to reduce radio path recalibration occurrences in beamforming applications. This feature is of critical importance for the successful implementation of 5G radio card massive MIMO systems.
Rohde & Schwarz's Vector Signal Generator and Signal Spectrum Analyzer
As Rohde & Schwarz sees it, the cellular industry faces daunting challenges working with the new spectrum that exists above 6 GHz—simply from the high frequency alone. Additionally, 400 MHz channel bandwidth, plus the multiple carrier aggregations can add up to a total bandwidth requirement of up to 2 GHz.
Test setup using the SMW200A and the FSW signal and spectrum analyzer. Image used courtesy of Rohde & Schwarz
With this test setup, a frequency range of up to 40 GHz and a 2 GHz internal modulation bandwidth allows the generation and analysis of realistic 5G scenarios. The need for external downconversion devices is eliminated by a carrier frequency of up to 90 GHz and up to 2 GHz of internal analysis.
The pair will have utility in R&D as well as in testing due to the many 5G-ready integrated personalities.
Keysight’s VXG Microwave Signal Generator
The VXG is a dual-channel, 44 GHz signal generator with a 2 GHz modulation bandwidth.
The VXG microwave signal generator. Image used courtesy of Keysight
Keysight explains that in order to overcome system path loss, multi-channel MIMO is inherent to millimeter-wave devices. Previously, this required actual over-the-air test methods. The VXG eliminates this troublesome step. The device enables quick switching from a blocker and interfere tests to dual-channel MIMO and beamforming tests. It does so without any requirement for hardware adjustment.
Additionally, the device provides access to a range of evolving 5G standards for testing base stations. It also includes receivers with channel coding and multi-antenna support and mobile terminal transmitters.
Will T&M Continue to Up Its Game?
As seen in the case of Renesas, Rohde & Schwarz, and Keysight Technologies, there are several ways to go about preparing for 5G—both in the stage of testing prototypes and in fine-tuning end-products.
Although current T&M equipment can indeed handle 5G testing, it seems that the more purpose-built a T&M device is, the better equipped it will be to overcome the challenges of complex waveforms, huge frequency ranges, component characterization, MIMO, and high-volume testing.
If you're a designer working with 5G devices, what adjustments have you made to account for the specificities of 5G? Share your experiences in the comments below.