Towards the Optimal Amplify-and-Forward Cooperative Diversity Scheme

How to find a cooperative diversity scheme that achieves the transmit diversity bound is still an open problem. In fact, all previously proposed amplify-and-forward (AF) and decode-and-forward (DF) schemes do not improve with the number of relays in terms of the diversity-multiplexing tradeoff (DMT) for multiplexing gains r higher than 0.5. In this work, we study the class of slotted amplify-andforward (SAF) schemes. We first establish an upper-bound on the DMT for any half-duplex SAF scheme with an arbitrary number of relays N and number of slots M. Then, we propose a naive SAF scheme that can exploit the potential diversity gain in the high multiplexing gain regime. More precisely, in certain conditions, the naive SAF scheme achieves the proposed DMT upper-bound which tends to the transmit diversity bound when M goes to infinity. In particular, for the two-relay case, the three-slot naive SAF scheme achieves the proposed upper-bound and outperforms the NAF scheme of Azarian et al. f...

• Type: Journal
• Year: 2006
• Where: CORR
• Authors: Sheng Yang, Jean-Claude Belfiore
• Keywords: Cooperative Diversity Scheme, CORR 2006, Education, Naive Saf Scheme, Transmit Diversity