Measure the RF characteristics of a 5G small cell’s radio or its components.
5G mmWave deployment continues and that means small cells. With that deployment comes the need for production testing of a small cell’s radio characteristics. To meet the need for over-the-air (OTA) testing of small cell units and their subsystems, Keysight Technologies has introduced the S9130A 5G Performance Multi-band Vector Transceiver, an instrument that provides test signals for mmWave receivers and, with software, analyzes signals received from transmitters.
The S9130A is a modular instrument based on the industry standard PXI platform. It’s heart is a M9415A Vector Transceiver module with bandwidth of 6 GHz, 8 GHz, or 12 GHz depending on option. The chassis also includes a timing module, a local oscillator, interconnects from the modules to a front panel, and other instruments as needed. One or two external mmWave remote radio heads (RRH) provide the mmWave signals to the device under test (DUT).
Figure 1 shows a typical test setup for OTA testing of an entire small cell or its components such as boards or modules. When asked about using an external RRH, Keysight’s Andrew Smail, director of network infrastructure manufacturing test solutions explained that keeping the RRH close to the DUT minimizes signal losses in cables and connectors, which minimizes the power needed to test a small cell’s receiver. Signals from the test chassis and RRH travel over intermediate frequency (IF) signals at up to 6 GHz, 8GHz, or 12 GHz. “Keeping the remote radio head close to the DUT can reduce loses by some 10 dB,” Smail told 5G Technology World. He also noted that, with an external RRH, test setups can share it based on test needs.
The S9130A works with several of Keysight’s RF test software applications. It comes with the company’s N90E1S91A 5G Multi-Band Vector Transceiver Application, but you can also use N7631C Signal Studio Pro for 5G NR, N7630C for pre-5G, N7608C for custom IQ and OFDM, 89600 PathWave VSA software, and KS8400A Test Automation Platform. Software lets you make measurements such as signal power, adjacent channel power (ACP)adjacent channel leakage ratio (ACLR), and error-vector magnitude (EVM).