5G is gaining momentum, and the 5G millimeter-wave (mmWave) frequency band provides abundant spectrum to support extremely high capacity, high throughput, low latency, and an increasing number of 5G mmWave devices, including mobile phones, laptops, and more.
However, the testing and characterization requirements of the latest 5G networks are exponentially higher than the previous generation networks in terms of network speed, bandwidth and synchronization. This requires testing new technologies and devices, including multiple-input multiple-output (MIMO) antenna arrays, high-GHz mmWave frequency signal testing and generation.
We often encounter the following two pain points:
Testing mixed signals: The DUT contains RF signals, digital signals, and analog signals that need to be tested. Multiple test environments must be set up. Buying all the different equipment requires a lot of money, and the expenditure is considerable.
MIMO/Bandwidth: Spectrum analyzers that were used to test 4G signals in the past cannot be used. 5G signals have a wider bandwidth and need to test more than one channel at the same time.
Figure 1. 5G SignalVu software measurements: ACPR, SEM, EVM, and power
How was beamforming introduced? We often hear beamformers enabling 5G mmWave, and it’s not hype. Beam management is a defining feature in mmWave communications and will play a key role in the future evolution of 5G wireless designs. Essentially, beamforming is a must-have feature for 5G mmWave to be useful to users.
Figure 2. 5G mmWave beamformer for a 4×4 MIMO dual-polarized base station (Renesas Electronics).
Beamforming uses multiple antennas to broadcast the same signal at slightly different times, allowing us to focus the wireless signal to a designated receiving device over a more directional connection, resulting in faster, higher quality, and more reliable communications stronger. The beamformer is the heart of the system as it drives each antenna array, which typically adds up to 512 antennas and 1,024 antenna elements. With so many patch antennas or antenna elements in each wireless unit, it is important to optimize overall performance, power consumption, and cost per wireless unit.
Figure 3. Beamformer MIMO OTA test setup (left), including RF power measurement (top right) and phase matching (bottom right).
With such a large number of elements, every aspect of the beamformer design is critical. The power dissipation is multiplied by 512, and any imperfections or mismatches between cells are amplified. You need good RMS phase error between elements, and good quadrature between phase and gain when steering the beam, otherwise the sideband levels will increase, compromising overall system performance. All of this makes beamformers a vital part of 5G mmWave wireless designs.
However, when testing all aspects of beamforming, there are challenges in the amount of man-hours required and the amount of equipment time. There are many devices, with many combinations of parameters and units, and you have to be careful about the coupling between the various units. From interference to blocking and Equivalent Isotropic Radiated Power (EIRP), measurements must be made in terms of the entire antenna area, so conducted measurements have become extremely important and over-the-air (OTA) measurements have become critical.
and then? We need more and wider bandwidth. We have pushed 5G to the boundaries of extremely high frequencies and high instantaneous bandwidth, and the next step for 6G is to optimize existing resources, make technology more environmentally friendly, and make better use of limited spectrum.
You can learn how Tektronix 5G test and calibration solutions are optimized for wireless technology, or watch our slideshow demonstrating 5G over-the-air measurements.
The Links: 2SB0710ARL LC171W03-B4K1
