China sets a new record in South China Sea submarine communication test

Chinese scientists working with the PLA receive signals transmitted from 30km away, achieving data transmission speed of 4,000 bps

Reading Time:3 minutes

Why you can trust SCMP

China is showing its dominance of underwater communications, with a new record set during recent testing of a new technology featuring a powerful method of data encoding. Photo: AFP

Stephen Chenin Beijing

Published: 12:00pm, 23 Aug 2024Updated: 10:41pm, 24 Aug 2024

Corrected [10:25pm, 24 Aug, 2024]

[10:25pm, 24 Aug, 2024]
This story has been updated to clarify that the polar code is a widely used technology and not only owned by Huawei.

A milestone for underwater communication has been achieved following testing of new technology that features a powerful method of data encoding, according to scientists involved in the project.

The 92150 unit of the People’s Liberation Army (PLA) in collaboration with Xiamen University recently conducted tests on the new underwater data transmission technology at an undisclosed location in the South China Sea, with a water depth of 3,000 metres (9,842 feet), far from the Chinese mainland.

Scientists deployed a small hydrophone 1,000 metres below the surface and successfully received signals transmitted from a ship that was 30km (18.6 miles) away, achieving a data transmission speed of 4,000 bits per second (bps).

This sets a new record for the performance of underwater acoustic communication equipment in open reports.

Extremely low-frequency (ELF) radio waves can penetrate the water, but their efficiency is very low, with only a few characters being transmitted per minute. Sound waves are more efficient but susceptible to refraction from the sea surface and seabed, ocean currents, and other environmental disturbances, making it difficult to transmit large amounts of data over long distances.

The previous record was also held by China. In March 2022, Zhejiang University and China State Shipbuilding Corporation conducted a similar test, achieving a distance of 14km (8.7 miles) at a rate of 3,000 bps.