Efficient Video on Demand (VoD) Services in Broadcast Environments

This thesis addresses the issue of reliable media delivery over broadcast channels. Sophisticated Video-on-Demand (VoD) broadcasting schemes based on Harmonic Broadcasting (HB) and Pyramidal Broadcasting (PB) allow receivers to tune into the ongoing transmission session of a video-stream at arbitrary time, while still being able to receive the multimedia sequence from the beginning and in complete, after short initial playout latency. Raptor codes, a class of fountain codes, are integrated in the broadcasting schemes by applying them to the application layer (AL-FEC). In addition, we provide service enhancements by using scalable video coding (SVC) to address heterogeneous receiver capabilities and receiving conditions as well as multiple site reception. We propose a Nested Harmonic broadcast scheme and suggest a set of guidelines of how transmission bandwidth should be allocated to the different quality layers in order to obtain best playout times. A realistic protocol environment is only slightly modified to support our system concept. Simulations of a DVB-h system show that our proposed scheme provides high gains in terms of early playouts compared to traditional broadcasting schemes with the same bandwidth expansion. Results also show the superiority of Raptor codes in the sense that it is always better to use Raptor codes for the whole bandwidth allocated for FEC instead of the IP layer multi-protocol encapsulation FEC (MPE-FEC) as DVB-h mandates.