China has announced plans to upgrade a civilian network of sensors and communications technology deep in the Western Pacific that it says is used in scientific research.
But analysts said the PLA could already be using a military-grade version of the communications technology to contact submarines operating far from base.
Buoys anchored between 400 and 500 metres beneath the surface of the Western Pacific would be upgraded this year, state media quoted scientists involved in the project as saying.
The researchers said the submerged sensors helped with research into areas such as climate change and ocean currents, and the upgrade would allow the equipment in the buoys to send data directly back to bases in China via satellite technology, Xinhua reported on Sunday.
China had deployed hundreds of buoys, including nearly 20 deep anchor points, in the Western Pacific since 2014, Xinhua said.