Wireless Image Transmission Using Rate-Compatible LDPC Codes

In this paper, we propose a combined source/channel coding scheme for transmission of images over fading channels. The proposed scheme employs rate-compatible low-density parity-check (RC-LDPC) codes along with embedded image coders such as JPEG2000 (JP2K) and set partitioning in hierarchical trees (SPIHT). The assignment of channel coding rates to source packets is performed by a fast trellis-based algorithm. Simulation results for the expected peak signal-to-noise ratio (PSNR) of reconstructed images, which are within 1dB of the capacity upper bound over a wide range of channel signal-to-noise ratios (SNR), show considerable improvement compared to existing results under similar conditions. We also investigate the sensitivity of the proposed scheme in the presence of channel estimation error at the transmitter and demonstrate that under most conditions our scheme is more robust compared to existing schemes.