Experimental Assessment of Adaptive Spatial Combining for Underwater Acoustic Communications

This paper presents a receiver structure of passive-phase conjugation (PPC) based adaptive spatial combining for underwater acoustic communications. Based on temporal diversity exploited by PPC processing, the presented structure exploits spatial diversity by adaptive multichannel combining. The structure was assessed in two field experiments which were conducted in two different seasons in Trondheim harbor. The experiments were carried out with the same configuration, but the channel physics were different due to different environmental conditions. A cross receiving array of 10 hydrophones, deployed in a water depth of 10 m, was used to collect the received waveform in a range of 2.0 km. By off-line signal processing, we have demonstrated the superior performance in exploiting spatial diversity for underwater communications.