Precoder design in cooperative systems with amplify-and-forward relaying

Cooperative communication systems using various relay protocols can achieve spatial diversity gains and enlarge the coverage. For the practical amplify-and-forward (AF) protocol, an optimal precoder design for cooperative systems with single-antenna nodes is proposed in this paper. Through iterative computation, we can obtain the exact precoder vector for the transmitter, by which spatial diversity can be efficiently exploited. The numerical results and simulations demonstrate the effectiveness of the proposed technique in improving the data detection error.