Duo test 5G RF transceivers up to 71 GHz

With Release 17, 3GPP will extend the frequency support of 5G NR mmWave bands into the unlicensed spectrum up to 71 GHz, a frequency band traditionally used by non-cellular standards like IEEE 802.11ad and 11ay.

This extension requires an adaptation of the physical layer, notably the addition of two new subcarrier spacings (480 kHz and 960 kHz), and the support of wider signal bandwidths of up to 2 GHz.

The support of this new frequency band poses new challenges to manufacturers of RF transceivers already targeting cellular applications, but also opportunities to those specialized thus far in the design and manufacturing of transceiver chipsets for non-cellular IEEE standards operating in these mmWave bands.

To address new testing challenges related to this bandwidth extension and to evaluate the performance of the latest generation RF transceiver chipsets, Rohde & Schwarz and Sivers Semiconductors teamed up to test RF transceivers for 5G NR up to 71 GHz.

For the joint testing efforts, Sivers Semiconductors provided an evaluation kit as device under test (DUT), powered by the state-of-art Radio Frequency Integrated Circuit (RFIC) TRXBF01 and the RF antenna module BFM06010.

The RFIC supports IEEE 802.11ad/ay modulations up to 64QAM over the full frequency range from 57 to 71 GHz.

The setup consisted of the R&S SMW200A vector signal generator, which supports frequencies up to 67 GHz – 72 GHz in over range mode – thanks to a new frequency option, and the R&S FSW85 signal and spectrum analyser, the only one with an integrated signal analysis bandwidth of up to 8.3 GHz and supporting RF frequencies up to 90 GHz.

The R&S ATS1800C compact antenna test range (CATR) based 5G NR mmWave test chamber completed the setup for over-the-air (OTA) testing.

To validate the transmitter performance of the DUT, the R&S SMW200A provides a differential analogue IQ baseband signal to the DUT, which performs the IQ modulation of the signal and up-conversion to the desired RF frequency.

The generated signal is compliant to Release 17 of the 5G NR 3GPP standard and uses a subcarrier spacing of 960 kHz and a modulation bandwidth of 2 GHz.

The DUT focuses its transmitter beam, which is created by 16 individually controllable antenna elements, in boresight direction towards the CATR reflector of the R&S ATS1800C. It bundles the signal to the feed antenna and provides it to the input of R&S FSW85, which then performs fully 3GPP compliant signal analysis.

To test the receiver performance of the DUT, the R&S SMW200A provides the 5G NR RF signal at 64 GHz (FR2-2), while connected to the feed antenna of the R&S ATS1800C. The feed antenna directs the signal towards the CATR reflector, which creates far-field conditions within a high-quality quiet zone (QZ) of 30 cm diameter. The integrated positioner allows repeatable RF measurements of the DUT within the QZ.

The Sivers Semiconductors chipset converts the received signal into baseband, which is captured by an R&S RTP oscilloscope, and processed for individual signal analysis with help of the R&S VSE vector signal explorer software or on the R&S FSW signal and spectrum analyser.

Erik Öjefors, Chief Technology Officer of the wireless business unit at Sivers Semiconductors, says: “This has been a valuable opportunity for Sivers Semiconductors to be able to provide yet another proof point of our world leading mmWave technology. Together with Rohde & Schwarz, we have demonstrated that the high performance of our mmWave transceiver RFICs provides a pathway for future NR-U deployments in the 60 GHz band based on the upcoming 3GPP Release 17 standard. Early access to test and measurement solutions capable of addressing new and upcoming standards such as 5G NR in the 60 GHz band is critical for our mission to be at the forefront of technology development.”

Andreas Pauly, Executive Vice President Test & Measurement at Rohde & Schwarz, says: “Together with Sivers Semiconductors, we set another milestone for the wireless industry. With our innovative test and measurement solutions we verify new functionalities within the 5G New Radio standard, demonstrating our continuous commitment to our partners and customers. Through this, we enable them to develop cutting-edge technology that will make advanced use cases of 5G for consumers and enterprises a reality.”