Wideband CDMA Waveforms for Large MIMO Sonar Systems

Multiple Input Multiple Output (MIMO) sonar systems offer new perspectives for target detection and underwater surveillance. The inherent principle of MIMO relies on transmitting several pulses from different transmitters. The MIMO waveform strategy can vary from applications to applications. But among the waveform space, orthogonal waveforms are arguably the most important sub-space. Purely orthogonal waveforms do not exist, and several approximations have been attempted for MIMO radar applications. These approaches include separating the waveforms in the time domain, the frequency domain or using pseudo orthogonal codes. In this paper we discuss the different radar waveform approaches from a sonar point of view and propose a novel CDMA (code division multiple access) waveform design, more suitable for large wideband MIMO systems.