Robust image transmission using source adaptive modulation with diversity

This paper presents a low-complexity method of transmitting digitally compressed imagery through AWGN and fading channels. The proposed method combines a wavelet-based image coder that employs phase scrambling and trellis-coded quantization (TCQ), and source adaptive modulation (SAM). We present two versions of SAM that utilize BPSK (SAM-TCQ) and 16-ary PPM (OSAM-TCQ), respectively. We then compare the performance of the OSAM system to that of a system that utilizes unequal error protection (UEP). In our previous work, the SAM-TCQ system was shown to perform as well as UEP-TCQ at high bit error rates (BER), and within 1 dB of the UEP-TCQ system at low bit error rates. In this work, we show that the OSAM-TCQ system performs nearly 4 dB better than UEP-TCQ at high bit error rates, and the same as the UEP-TCQ system at low bit error rates, with much lower complexity than the UEP-based system