Composite photo taken on Dec 10, 2016 shows a quantum communication ground station in Southwest China's Tibet autonomous region. [Photo/Xinhua]

"This requires extremely precise measurement," said Wang. "Receiving the entanglement is like catching coins dropped from a plane with a piggy bank."

Moreover, quantum entanglements cannot be amplified like radio signals, so scientists still need to overcome disturbances when delivering photon entanglement over thousands of kilometers.