Cross-layer design of adaptive modulation and coding for multicast system with random network coding

This paper deals with a cross-layer design that combines link adaptation in the physical layer with random network coding for layered video multicasting in a cellular system. The objective is to design the optimum signal-to-noise ratio (SNR) threshold for adaptive modulation and coding (AMC) that can satisfy the target frame loss rate (FLS) under a delay constraint associated with real-time multicasting services. A common uplink feedback channel shared by all users is introduced to reduce the redundant transmission of the random network-coded packets, so that no unnecessarily redundant transmission can be made when the multicast packet is successful for all receivers, avoiding the overhead of the uplink wireless resource associated with each user for individual feedback. Based on our analytical results on spectral efficiency for the cellular system, we show that the aggressive AMC design approach with the common feedback channel in the multicast system outperforms all other approaches.