Carousel-based wireless multicast transmission over WLANs employing raptor codes

Data carousels are a traditional way of providing reliable multicast transmission without the need for per-user feedback channels. Application Layer Forward Error Correction (AL-FEC) codes (in the form of Reed-Solomon codes) have previously been used to improve the performance of data carousels. However, until now, their joint design has only been investigated analytically with unrealistic random packet loss values. In this paper we investigate the joint design of an AL-FEC enhanced data carousel for use in an outdoor 802.11 multicast wireless LAN. We use an advanced end-to-end system level simulator to determine the optimal design parameters. Furthermore, we extend previous research in this area by combining data carousels with AL-FEC based on fountain codes. Our simulation results show that this new approach is more efficient than traditional Reed-Solomon block codes. More specifically, average download times are reduced, percentages of satisfied users are increased and valuable network resources are more efficiently utilized.