Joint channel estimation and raptor decoding over fading channel

In this paper, we present a comparative study of joint channel estimation and decoding of factor graph-based codes over flat fading channels. A new simple channel approximation scheme is proposed. Specifically, when channel state information is not available at the receiver, a simpler approach is to estimate the channel state of a group of received symbols, then use the approximated value of the channel with the received signal to compute the log likelihood ratio. Simulation results show that the proposed scheme exhibits about 0.4 dB loss compared to the optimal solution when perfect channel state information is available at the receiver.