Multi-rate Multicasting with Network Coding

Single-rate multicasting may yield low utilization of the network resources when a subset of the receivers creates a bottleneck for the whole multicast group. Thus, practical multirate multicasting strategies are required to allow users with better channels to achieve maximum performance. While earlier studies have investigated such mechanisms using routing strategies over fixed trees, in this work we consider the possibility of using network coding without a given subgraph. Our scheme identifies the optimal routes and provides the utility maximizing rate allocation and coding solution. We also propose and investigate a nested multicasting method to reduce the complexity of the original scheme for practical implementation.