New results on radiography image transmission with unequal error protection using protograph double LDPC codes

In this paper, we propose a new joint source-channel coding (JSCC) system with unequal error protection (UEP) constructed from protograph low-density parity-check (P-LDPC) codes for medical image transmission over additive white Gaussian noise (AWGN) channel to minimize the end to end image distortion. In order to make the P-LDPC codes suitable for the image transmission with UEP system, we combine two Tanner graphs, one of which is derived by protograph. A typical radiography image and other two gray-scale images are applied in our simulation. And we compare the peak signal-to-ratio (PSNR) performance of our codes with a previous work on UEP using P-LDPC codes and some other UEP schemes based on LDPC codes and Turbo codes. Simulation results indicate that the proposed scheme can apparently increase the PSNR value of the received images and reconstruct the transmitted images completely and correctly even at a very low signal-to-noise ratio (SNR). In addition, the proposed scheme can reduce the complexity of the image transmission model of our previous work and is superior than other UEP schemes with 0.5-2.5 dB increase in SNR.