R&S Evaluates Signal Propagation of mm-Wave 5G Terminals in Different Environments

Rohde & Schwarz along with China Mobile and MediaTek has successfully carried out a technical trial of a 5G prototype terminal. The main purpose of the trial was to verify the signal characteristics and propagation of the mmWave terminal in different environments, both indoors and outdoors, and to investigate the effect that beam tracking and array antenna switching have on maintaining the stability of the mmWave signal.

In the technical trials, an R&S SMW200A vector signal generator simulated the downlink signal of the base stations. The device under test (DUT) was an MTK mmWave prototype terminal. This prototype terminal, roughly the size as a normal mobile phone, uses a highly integrated antenna array technology with beam tracking and beam forming capabilities. Shielding effect is a phenomenon used to describe how different materials, placed in the path of transmitted mmWave signals, interfere with the reception of the signals. In the technical trials, the shielding effects of glass, wood, textiles, metal, plants and especially the influence of the direct shielding of the human body were researched by placing them between a horn antenna and the DUT.

The result of the trial indicated that the mmWave signal can be seriously affected by the shielding effect of objects. The human body shielding can cause the signal attenuation to be as high as 10-20 dB. To solve this problem, further optimization of both the terminal and the network is required. For example, antenna designers may need to introduce more flexible solutions, such as multiple antenna arrays that enable discovering the strongest signal by switching between antennas.

5G mmWave can offer many benefits, including a higher bandwidth and faster data throughtput. However, engineers designing 5G based solutions also need to be aware of the challenges concerning the use of high frequencies, such as shielding effects and signal propagation. China Mobile will continue to work with partners such as MediaTek and Rohde & Schwarz in exploring solutions concerning 5G mmWave in order to be ready for the commercial deployment of 5G mmWave technology.