Experimental Study of Underwater Acoustic Reconfigurable Intelligent Surfaces with Synthetic Reflection
This work addresses communication challenges in oceanic environments, offering a novel hardware solution with significant performance gains, though it is incremental as it adapts existing RIS concepts to underwater acoustics.
This paper tackles the problem of long-range, high-speed underwater acoustic communication by developing an underwater acoustic reconfigurable intelligent surface (UA-RIS) that uses synthetic reflection to steer beams, with experimental results showing communication range extensions of up to 66% and SNR boosts of up to 4.2 dB.
This paper presents an underwater acoustic reconfigurable intelligent surface (UA-RIS) designed for long-range, high-speed, and environmentally friendly communication in oceanic environments. The proposed UA-RIS comprises multiple pairs of acoustic reflectors that utilize a synthetic reflection scheme to flexibly control the amplitude and phase of reflected waves. This capability enables precise beam steering to enhance or attenuate sound levels in specific directions. A prototype UA-RIS with 4*6 acoustic reflection units is constructed and tested in both tank and lake environments to evaluate performance. Experimental results using a continuous wave (CW) as the source signal demonstrate that the prototype is capable of effectively pointing reflected waves to targeted directions while minimizing side lobes through synthetic reflection. Field tests reveal that deploying the UA-RIS on the sender side considerably extends communication ranges by 28% in deep water and 46% in shallow waters. Furthermore, with a fixed communication distance, positioning the UA-RIS at the transmitter side substantially boosts the receiving signal-to-noise ratio (SNR), with an average increase of 2.13 dB and peaks up to 2.92 dB. When positioned on the receiver side, the UA-RIS can expand the communication range in shallow and deep water environments by 40.6% and 66%, respectively. Moreover, placing the UA-RIS close to the receiver enhances SNR by an average of 2.56 dB, reaching up to 4.2 dB under certain circumstances.