25-05-2025
China enables 375-mile long-range submarine messaging with acoustic breakthrough
Chinese researchers have achieved a major breakthrough in underwater communication, successfully transmitting acoustic data without errors across 375 miles in the ocean. The achievement, detailed in China's leading acoustics journal Acta Acustica, represents a major step toward making long-range undersea messaging a practical reality—a technology with far-reaching civilian and military implications.
In 2010, a US Navy experiment demonstrated that underwater communication was possible across 342 miles, and whales are known to exchange low-frequency songs over distances exceeding 5,000 miles. The distance covered by China with its latest innovation is roughly equal to the stretch between Taipei and the US military base in Okinawa.
Yet achieving zero-error transmission over such vast ranges has remained a major challenge. For some users—particularly the military—even slight data corruption is unacceptable for critical operations like activating dormant underwater drones or coordinating precision attacks, the South China Morning Post reported.
Furthermore, underwater communication faces steep obstacles as seawater scatters sound into tangled echoes, Doppler shifts distort signals from moving sources, and ambient noise easily drowns out faint transmissions.
Professor He Chengbing and his team at Northwestern Polytechnical University in Shaanxi, China developed a self-tuning system that can identify signal clusters in noisy underwater environments without requiring prior knowledge of seabed topography—a key advantage for naval applications.
They also created an innovative algorithm that converts turbulent, time-varying channels into quasi-static 'acoustic snapshots' through mathematical transforms, enabling iterative error correction similar to sharpening a blurry photo with multiple exposures.
However, the technology is still highly demanding in terms of computing power—processing a single transmission reportedly requires teraflop-scale performance, making it impractical for real-time use on small drones. Additionally, sudden changes in the communication channel caused by storms or abrupt maneuvers pose significant challenges to its reliability.
In 2021, tests conducted at an undisclosed deep-sea location with an average depth of 3.4 miles achieved zero-bit-error acoustic transmissions over distances of about 202 miles and 370 miles.
Using an eight-element hydrophone array attached to a buoy and coded QPSK signals, the system reached a transmission speed of 37.5 bits per second during the longer-range trial. These experiments confirmed the method's effectiveness in enabling error-free underwater acoustic communication across vast distances.
According to the research paper in Acta Acustica, the 176-decibel sound source employed during the sea trials operated within the extremely low-frequency range, which is ideal for long-distance underwater communication due to its ability to travel farther with less attenuation.
Recognized as one of China's 'Seven Sons of National Defence', Northwestern Polytechnical University has faced ongoing U.S. sanctions and cyberattacks due to its work in aerospace and naval research.
Since establishing its underwater acoustics department in the 1950s, the university's graduates have contributed significantly to the development of China's most advanced warships and marine surveillance networks, according to its official website.
