5G signal analysis meets Verizon trial specifications

In July 2016, Verizon Wireless, a tier 1 network operator in the United States, supported by leading infrastructure, chipset and terminal manufacturers, published technical specifications that describe the physical layer characteristics of a 5G signal.

The specified signal is derived from LTE and adapted to be used at cm frequencies, initially 28GHz but also 39GHz.

Those frequencies were recently allocated for 5G wireless communications by the local regulator, the Federal Communications Commission (FCC).

The proprietary signal is a multicarrier OFDM signal with a subcarrier spacing of 75kHz. It is aiming for a bandwidth of 100MHz per component carrier. Up to eight carriers can be aggregated. The basic mode of operation is TDD.

Built-in flexibility enables the Rohde & Schwarz signal generation and analysis instruments to support the basic characteristic of the specified 5G Verizon signal. The R&S SMW200A vector signal generator equipped with the R&S SMW-K114 5G waveform candidate software option makes it easy to configure OFDM signals with the required 75 kHz subcarrier spacing and 100 MHz bandwidth. Additionally, preamble and user data settings enable creation of 5G signal with the basic characteristics as specified by the Verizon 5G technical forum.

This means that reference symbols can be set, and data modulation such as QPSK, 16QAM, 64QAM and even higher-order modulation schemes such as 256QAM can be applied.

Using the R&S FS-K96 OFDM vector signal analysis software in combination with the R&S FSW signal and spectrum analyser allows the full characterisation of such a 5G signal by simply loading into the software a configuration file that reflects the parameterisation of the 5G Verizon signal.

When characterising DUTs such as newly developed power amplifiers for the cm frequency range, test instruments themselves can influence the measurement results.

Rohde & Schwarz achieved outstanding performance with the R&S SMW200A and R&S FSW in the trial.

When using the test instruments to measure the EVM of a 5G signal at 28GHz, measurement results were below 1 % across a 10 dB power sweep, meaning that the test instruments did not impact the measurement.