KAWAGOE, Saitama Prefecture--An unmanned construction machine was remotely controlled via a next-generation 5G wireless system in an experiment here conducted by KDDI Corp.

The telecommunications giant, which operates the au cellphone brand, demonstrated Feb. 15 how a worker watched high-definition 3-D imagery while operating the robust equipment.

The technology will allow restoration work to start promptly at disaster sites that humans cannot enter because of ongoing danger, such as in the immediate aftermath of a landslide, KDDI officials said.

The 5G, or fifth-generation, mobile technology is expected to be put to practical use in 2020.

In the experiment conducted jointly by KDDI, general contractor Obayashi Corp. and electronics giant NEC Corp., images captured by two 4K cameras on a heavy machine were transmitted via 5G radio waves to a room 70 meters away, where they were shown on a 3-D display. The operator was seen assessing the depth dimension as he lifted rubble.

Officials said the transmission of images requires a data rate of 200 megabits per second (Mbps), about 10 times the capacity of fourth-generation (4G) wireless technology, which is used by state-of-the-art cellphones.

The 5G technology will allow a heavy machine to be controlled remotely as soon as it has been brought within range of the radio waves, the officials said.