Multisource network coding with two sinks

Network coding shows that the data rate can be increased if information is allowed to be encoded in the network nodes. The recent work of S.-Y.R. Li et al. (see IEEE Trans. Inform. Theory, vol.49, no.2, p.371-81, 2003) and R. Koetter and M. Medard (see Proc. INFOCOM, 2002) shows that linear network coding is sufficient for a single source multicast network. The restrictiveness of the use of linear code is still an unknown in the general multisource multicast network. We characterize the achievable information rate region for a single source node multi-source multicast network with two sinks. We further show that linear coding is sufficient for achieving the maximum network capacity.