Receive knowledge only power allocation for nonregenerative cooperative MIMO communication

Amplify-and-forward (AF) is one of the most popular approaches to transmit information over a cooperative multi-input multi-output (MIMO) relay channel. In AF, relay simply amplifies and retransmits the received signal from the source by relying only on the receive channel state information (CSI) available at the relay. In this paper we propose two novel power allocation methods for nonregenerative cooperative communication, assuming as in original AF that only receive CSI is available at the relay. Both methods have been designed to maximize the mutual information of the relay link: the first method by using an analytical solution and the second by solving a concave optimization problem. Performance of both our methods have been compared against traditional AF power allocation techniques in a MIMO environment, and results have demonstrated the efficiency of these methods in terms of mutual information and bit-error rate.