  We present a superposition coding scheme for communication over a network,
which combines partial decode and forward and noisy network coding. This hybrid
scheme is termed as superposition noisy network coding. The scheme is designed
and analyzed for single relay channel, single source multicast network and
multiple source multicast network. The achievable rate region is determined for
each case. The special cases of Gaussian single relay channel and two way relay
channel are analyzed for superposition noisy network coding. The achievable
rate of the proposed scheme is higher than the existing schemes of noisy
network coding and compress-forward.
