5g has a strong development momentum. 5g millimeter wave band provides rich spectrum to support 5g millimeter wave devices with high capacity, high throughput, low time delay and increasing number, including mobile phones, laptops and so on.
However, in terms of network speed, bandwidth and synchronization, the demand for testing and characterization of the latest 5g network is exponentially higher than that of the previous generation network. This requires testing new technologies and devices, including multiple input multiple output (MIMO) antenna arrays, high GHz millimeter wave frequency signal testing and generation.
We often encounter the following two pain points:
·Test mixed signal: DUT includes RF signal, digital signal, analog signal and other signals that need to be tested. Multiple test environments must be set. It takes a lot of money to buy all different equipment, and the expenditure is considerable.
·MIMO / bandwidth: the spectrum analyzer used to test 4G signals in the past cannot be used. 5g signal bandwidth is wider, and more than one channel needs to be tested at the same time.
Figure 1. 5g signalvu software measurement: ACPR, SEM, EVM and power
How was beamforming introduced? We often hear that the beamformer enables 5g millimeter wave, which is not hype. Beam management is a decisive feature in millimeter wave communication and will play a key role in the future development of 5g wireless design. In essence, beamforming is a necessary function to make 5g millimeter wave effective to users.
Figure 2. 5g millimeter wave beam former for 4×4 MIMO dual polarization base station (Renesas Electronics).
Beamforming uses multiple antennas to broadcast the same signal at slightly different times, so that we can focus the wireless signal to the specified receiving equipment through a more directional connection, so as to make the communication faster, higher quality and stronger reliability. The beamformer is the core of the system because it drives each antenna array. Usually, there are 512 antennas and 1024 antenna units together. Since there are so many patch antennas or antenna elements in each wireless unit, it is very important to optimize the overall performance, power consumption and cost of each wireless unit.
Figure 3. Beamformer MIMO OTA test setup (left), including RF power measurement (upper right) and phase matching (lower right).
Due to such a large number of units, every aspect of beamformer design is very important. The power consumption will be multiplied by 512, and any non ideal or mismatch between units will also be amplified. You need a good RMS phase error between units. When manipulating the beam, you need a good orthogonality between the phase and gain, otherwise the side charge level will be improved, which will endanger the overall system performance. All these make the beamformer a vital part of 5g millimeter wave wireless design.
However, when testing all aspects of beamforming, the required number of man hours and equipment time are challenged. There are many devices, many parameters and unit combinations, and you must be careful about the coupling between various units. From interference to blocking and equivalent omnidirectional radiated power (EIRP), it must be measured from the whole antenna area. Therefore, conduction measurement becomes very important, and air (OTA) measurement becomes very important.
so what? We need more and wider bandwidth. We have pushed 5g to the boundary of extremely high frequency and high instantaneous bandwidth. The next step 6G is to optimize existing resources, make science and technology more environmentally friendly and make better use of the limited spectrum.
You can learn how the Tektronix 5g test and calibration solution is optimized for wireless technology, or watch our slide show 5g aerial measurement.