Receiver configuration and testbed development for underwater cognitive channelization

We propose a receiver configuration and we develop a software-defined-radio testbed for real-time cognitive underwater multiple-access communications. The proposed receiver is fully reconfigurable and executes (i) all-spectrum cognitive channelization and (ii) combined synchronization, channel estimation, and demodulation. Online (real-time) experimental field studies using in-house built modems demonstrate our theoretical developments and show that cognitive channelization is a powerful proposition for underwater communications that leads to significant improvement of spectrum utilization. Even in the absence of interference, due to the noise characteristics of the acoustic channel, cognitive channelization offers significant performance improvements in terms of receiver pre-detection signal-to-interference-plus-noise-ratio and bit-error-rate.