Improvement of 5G OTA performance and capacity using different polarization schemes and algorithms verification

Abstract

The goal of this thesis work is to study the impact of polarization compared to already deployed environment for Over the Air (OTA) testing. The existing environment consists of Radio Frequency (RF) chamber containing multiple input multiple output (MIMO) transceiver on one end and user equipment (UE) on the other end: connected to Vivaldi antennas via RF cables, an oscilloscope to visualize beams and RF box. The chamber is confined with absorbers at each end to avoid multipath propagation. To begin the testing and enablement of flexibility inside OTA chamber, a rotator motor is installed to Vivaldi antenna capable of setting any antenna position remotely to study the impact at different reception angles. Different test cases were performed to relate the performance of system with existing setup and algorithm verification was carried out.

In theory part, wireless technologies evolution from 1st generation till 5th generation (5G) was discussed. 5G was discussed in detail due to its utilization in present thesis work. Wireless technologies discussion was followed by MIMO classifications and techniques which are essential in 5G system which further expanded the study to beamforming techniques and ended with brief introduction of polarization. The mentioned discussion was crucial to deploy test environment and better understanding of test case measurement and conclusion from results.

During the testing phase, downlink throughput of system was seen to be improved at vertical polarization with 90-degrees reception angle at cell edge compared to existing location. Moreover, polarization request from user equipment was found to be more stabilized at mentioned angle. One key finding was from continuous rotation test case, where degradation of throughput was observed with circular polarization request with slow and fast speed rotations.