Large system design and analysis of protocols for decode-forward relay networks

In this work we consider a relay assisted CDMA network with a large number of sources and half duplex relays and a unique destination. We propose two relaying protocols called direct relaying (DR) and full relaying (FR). By dividing the relays in groups and adopting different forwarding delays for each group both protocols introduce diversity which depends on the number of groups and on the protocol. In DR mode, the relays forward only signals received directly from the sources. In FR mode, relays forward both signals received by the sources and the other relay groups by applying network coding at the physical layer. This implies a different level of diversity at the destination for the two schemes. Then, we propose an analytical framework for the analysis of the achievable rates in such a network, as the number of nodes and relays become asymptotically large.