Cooperative diversity is a virtual multiple antenna techniques which exploits user diversity by allowing for the destination node to decode the multiple received signal from the relayed and direct nodes in wireless multihop networks. Conventional single hop wireless systems use direct transmission where a receiver node decodes information only based on the received signal from the source node while regarding the relayed signal as interference, whereas the cooperative diversity considers the other signal as contribution. That is, cooperative diversity allows the destination node to decode the information from the combination of two differently received signals from the source and relay nodes. Hence, it can be seen that cooperative diversity is an virtual antenna diversity that uses distribu