Parallel Relay Network with Orthogonal Components: Capacity and Power Allocation

The authors consider a relay network in which the source-destination pair is augmented by a set of parallel relays. In this relay network, the source transmits to the destination and the relays over multiple orthogonal channel components. Practically, orthogonal channel components is motivated by the fact that a relay cannot receive and then transmit by using the same frequency band. For this relay network, lower bound on the capacity is shown to match the upper bound, and thus establish the capacity of the discrete memoryless physically degraded relay channel. Then, the capacity result is extended to the case of additive white Gaussian noise channel. Finally, rigorous simulation results are carried out to verify the analytical results.