What is massive MIMO?

Beamforming requires precise, real-time channel state information (CSI) from the UE to customize the beam. It needs full digital control of the amplitude and phase at every antenna element. In a predominantly Line-of-Sight (LoS) channel with users in different locations, beamforming will generate a beam towards each user simultaneously. More transmit/receive (Tx/Rx) antennas help compensate for high losses at mmWave frequencies. A greater number of radiating elements enables you to steer the antenna in a certain direction. The beams become narrower and more defined as the number of antenna elements increases. All the available power is transmitted in a certain direction instead of being wasted in many different ones. In the 5G New Radio (NR) initial access procedure, multiple synchronization signal blocks (SSBs) are sent in a burst set period, each SSB potentially in a different beam. The UE identifies every SSB in the burst set using the physical broadcast channel demodulation reference signal (PBCH DMRS) and the rest of the SSB index carried by the broadcast channel. After sweeping the beam, the UE then selects the best SSB and establishes the connection.

What is over-the-air (OTA) RF testing?

OTA RF testing refers to the process of evaluating the performance and behavior of wireless devices by transmitting and receiving RF signals through the air, without using direct cable connections. Unlike traditional conductive testing, OTA tests replicate real-world usage scenarios, including the effects of antenna performance, propagation conditions, multipath, interference, and environmental influences. OTA testing typically involves placing the Device Under Test (DUT) within an RF-shielded chamber equipped with calibrated antennas. Signals are radiated toward the DUT from various angles, distances, and polarizations to assess parameters such as: • r adiated power and sensitivity • a ntenna efficiency and gain • t hroughput and data rates • s patial correlation and MIMO capacity This methodology is essential for modern wireless technologies, including 4G LTE, 5G NR (especially at mmWave frequencies), Wi-Fi, IoT devices, and satellite communications, ensuring reliable real-world performance before product deployment.

What are the requirements for beamforming?

Beamforming requires precise, real-time channel state information (CSI) from the UE to customize the beam. It needs full digital control of the amplitude and phase at every antenna element. In a predominantly line of sight (LoS) channel with users in different locations, beamforming will generate a beam towards each user simultaneously. More transmit/receive (Tx/Rx) antennas help compensate for high losses at mmWave frequencies. A greater number of radiating elements enables you to steer the antenna in a certain direction. The beams become narrower and more defined as the number of antenna elements increases. All the available power is transmitted in a certain direction instead of being wasted in many different ones. In the 5G New Radio (NR) initial access procedure, multiple synchronization signal blocks (SSBs) are sent in a burst set period, each SSB potentially in a different beam. The UE identifies every SSB in the burst set using the physical broadcast channel demodulation reference signal (PBCH DMRS) and the rest of the SSB index carried by the broadcast channel. After sweeping the beam, the UE then selects the best SSB and establishes the connection.

Multiband Vector Transceivers

Broad frequency coverage, compact design, and precise testing

Keysight multiband RF vector transceivers are now offered in one capability class, the VT5-class, and include the S9100A-S9130A multiband RF vector transceivers. These transceivers provide broad frequency coverage and wide bandwidth, enabling comprehensive testing of 5G infrastructure equipment, including transmit, receive, fading simulation, and over-the-air (OTA) scenarios. They support both 5G frequency range 1 (FR1, sub-6 GHz) and frequency range 2 (FR2, mmWave) bands in a compact, scalable system that streamlines setup and adapts to evolving needs. Leverage the extensive Keysight software portfolio for signal generation and analysis and streamlined automation. Choose on of our popular configurations or configure one specific to your application. Need help selecting? Check out the resources below.

Full-spectrum 5G testing

Supports end-to-end 5G testing across FR1 (sub-6 GHz) and FR2 (mmWave) bands in a single system, minimizing rack space and simplifying test setups.

Wide instantaneous bandwidth

Enables single-measurement capture and analysis of complex wireless signals, improving test speed, accuracy, and support for technologies like multiple-input multiple-output (MIMO) and beamforming.

Integrated and scalable

Combines critical test functions, including transmit, receive, fading simulation, and over-the-air (OTA) testing, into a single scalable system, ensuring interoperability and optimized workflows.

Multichannel synchronization

Enables tight timing and phase alignment across multiple transmit and receive paths, important for complex wireless testing like multi-antenna systems and phased array validation.