Efficient space-time block codes for cooperative MIMO communications

The cooperative techniques have recently taken a lot of attention in the recent few years due to their efficiency in radio mobile networks specially when the direct link between the source and the destination is lost. However, their combination with the multiple input multiple output (MIMO) schemes requires further study since new strategies of cooperation are expected when the MIMO component is added to the cooperation scheme construction. In this paper, we propose a double-layer space-time (DLST) code in a distributed way between the relays in order to emulate the MIMO transmission scheme between the relays. The DLST is compared with some of the most promising codes found in the literature. We show that the proposed code is very efficient whatever the transmitted powers by the relays are. This efficiency is verified in both amplify and forward (AF) and decode and forward (DF) algorithms. We show that a gain of at least 1 dB is obtained through DLST compared to conventional MIMO schemes in cooperative communications whatever the transmission scenario is.