Sparse Nonorthogonal Wavelet Division Multiplexing for Underwater Sonar Image Transmission

Sonar image transmission is very important for undersea expeditions, but it is extremely challenging due to the narrow bandwidth of underwater acoustic (UWA) channel. To improve the spectral efficiency of multicarrier modulation for sonar image transmission, a sparse nonorthogonal wavelet division multiplexing (SN-OWDM) scheme is proposed based on sparse representation. The designed subcarriers matrix of SN-OWDM is regarded as the basis of sparse representation. The transmitted data is solved by the sparse representation of input symbols. The results show that the proposed SN-OWDM scheme needs less frequency resource compared with orthogonal frequency division multiplexing (OFDM) with higher peak signal-to-noise ratio (PSNR) and lower peak-to-average power ratio (PAPR) as well.