Capacity Analysis for Cooperative Two-Relay Channel

The capacity of relay channel is determined not only by the number of relays but also the relations among them. Cooperation among relays will greatly improve the network capacity by further reducing information uncertainty. Based on this theory, this paper introduces cooperative two-relay channel models with or without path loss, as well as the method for their capacity analysis. In these models, the work mode of the relays has two schemes, that is, the two relays select the same or different codebooks respectively. On calculating the capacity, we will analyze it without path loss firstly. Then based on this very result, we will further analyze the capacity with path loss. A numerical example without path loss is given in order to certify the result. It shows that the capacity is confined to the combination of the broadcast channel and multi-access channel and by finding the best way of power allocations we can achieve the maximum channel capacity.