Reliable Wireless Transmission for Layered Source Coding

This paper studies the transmission of layered source coding over error prone wireless channels. The focus is mainly on two strategies: with and without the availability of feedback between the receiver and the transmitter. When feedback is not available, the source layers are transmitted using unequal error protection (UEP), which is provided by hierarchical modulation and channel coding. A novel combination of hierarchical modulation and channel coding is proposed to improve the performance and increase the number of priorities offered by the UEP system. When a feedback channel is available, the investigation of adaptive techniques shows that the system can adapt its parameters (modulation mode, channel coding ratio, etc.) according to channel conditions to give the best achievable service quality. Retransmission techniques are also investigated to improve further the service quality, especially in a fading environment