Joint source channel coding of images over frequency selective fading channels with feedback using DCT and multicarrier block pulse amplitude modulation

Abstract

A novel approach to joint source channel coding over frequency selective fading channels with feedback using source decomposition and multicarrier block pulse amplitude modulation is proposed. A set of representative frequency responses for a slowly varying frequency selective channel, corresponding to channel states, is mean square error sense. The amount of source information transmitted per channel symbol frame depends on the channel conditions: during favorable conditions, twice as much information is transmitted; during deep fades, no information is transmitted. We design linear encoders and decoders for each of the states, using multicarrier block pulse amplitude modulation. Our approach results in graceful degradation of the decoded signal and good performance in the low SNR region. Simulation results are presented for the "Lena" image and compared to the OPTA bound.