Receiver Heterogeneity Helps: Network Coding for Wireless Multi-Layer Multicast

Heterogeneity amongst devices and desired service are commonly seen as a source of additional challenges for setting up an efficient multi-layer multicast service. In particular, devices requiring only the base layer can become a key bottleneck to the performance for other devices. This paper studies the case of a wireless multi-layer multicast setting and shows that the judicious use of network coding allows devices with different computational capabilities to trade-off processing complexity for an improved quality of service. As a consequence, individual devices can determine their required effort, while bringing significant advantages to the system as a whole. Network coding is used as a key element to reduce signaling in order to deliver the multicast service. More importantly, our proposed approach focuses on creating some structure in the transmitted stream by allowing inter-layer coding, in order to create more opportunities for recovering the base layer promptly. We propose a design and analyze its delay distribution and mean performance under various system conditions and present a first implementation to verify our analysis and demonstrate the applicability of our approach.