  We consider the problem of transmitting correlated data after independent
encoding to a central receiver through orthogonal channels. We assume that the
channel state information is not known at the transmitter. The receiver has
access to both the source correlation and the channel state information. We
provide a generic framework for analyzing the performance of joint iterative
decoding, using density evolution. Using differential evolution, we design
punctured systematic LDPC codes to maximize the region of achievable channel
conditions, with joint iterative decoding. The main contribution of this paper
is to demonstrate that properly designed LDPC can perform well simultaneously
over a wide range of channel parameters.
