Broadband RF communications in underwater environments using multi-carrier modulation

We describe new methods that solve well-known problems associated with high throughput, robust communication in underwater environments. By robust, we imply simultaneous increases in enabled underwater communication data rates, range, and reliability. Our methods borrow concepts from advanced multi-carrier modulation using orthogonal frequency division multiplexing (OFDM), multiple input multiple output (MIMO) space time codes (e.g. Alamouti diversity), and zero carrier frequency ultra wideband (UWB) wireless. In addition, we discuss system optimization involving the elimination of the phase synthesizer and analog mixer through direct sampling of the RF antenna port.