On the capacity of a relay network with orthogonal components

In this paper, we consider the relay network in which the source can transmit to the relays and the destination over multiple orthogonal frequency bands. In this relay network, the source–destination pair is supported by a set of cascaded intermediate nodes, the relays. Practically, transmission over orthogonal bands is selected since these intermediate nodes cannot simultaneously receive and forward signals over the same frequency band. For this relay network, we initially derive the capacity of the discrete memoryless model and then extend this result to the additive white Gaussian noise (AWGN) channel. Our numerical results show that the developed encoding scheme can attain a rate higher than the available results in the literature. Further, the benefits of optimally allocating the total available power between the source and the two relays is also numerically investigated.