Performance analysis for the AF-based frequency division cooperative broadcast channel

This paper considers a system where one transmitter broadcasts a single common message to two receivers. These receivers can cooperate through a bidirectional channel that is assumed to be orthogonal to the downlink channel. For the case where the assumed cooperation protocol is amplify-and-forward we calculated the final equivalent SNR in the MRC output at each receiver for an arbitrary number of cooperation exchanges. The corresponding analytical expressions can then be used for evaluating different performance criteria in order to discuss issues such as: Which receiver should start cooperating first? Is there an optimum number of cooperation exchanges? What is the difference between asymmetric and symmetric cooperations?