Date Added: May 2012
In this paper, the authors employ a relay to assist in transmission from a source to a destination over a fixed number of time slots. They seek to minimize the expected sum transmission energy used by the source and relay, by choosing the transmission power of each node dynamically slot by slot. They assume that both receivers, namely the relay and the destination, can accumulate mutual information across previous and present slots by using earlier received packets for joint decoding. Assuming availability of causal Channel State Information (CSI) at all transmitters, they obtain the structure of the optimal solutions by dynamic programming.