SK announced last year that it was building a mmWave system with Samsung at its test bed in Bundang. They have been looking at issues such as service coverage, transmission speed, latency and other radio performance indicators to check the quality of service. The tests used a 28GHz transmitter and receiver antenna and propagation direction control technology based on 3D beamforming. The latter is key to compensating for the high propagation path loss in the high spectrum. The results of the tests will contribute to building a pilot 5G network for testing later this year.