End-to-end performance of transmission systems with relays over Rayleigh-fading channels
IEEE Transactions on Wireless Communications
Symbol error probabilities for general Cooperative links
IEEE Transactions on Wireless Communications
Distributed space-time coding for regenerative relay networks
IEEE Transactions on Wireless Communications
On the performance of distributed space-time coding systems with one and two non-regenerative relays
IEEE Transactions on Wireless Communications
IEEE Transactions on Information Theory
Space-time block codes from orthogonal designs
IEEE Transactions on Information Theory
Distributed space-time-coded protocols for exploiting cooperative diversity in wireless networks
IEEE Transactions on Information Theory
A simple transmit diversity technique for wireless communications
IEEE Journal on Selected Areas in Communications
Fading relay channels: performance limits and space-time signal design
IEEE Journal on Selected Areas in Communications
Hi-index | 0.00 |
Cooperative space-time block coding (STBC) is a distributed way to exploit spatial diversity. Because of its simplicity, the amplify-and-forward (AF) strategy is often used at relays. However, the exact performance of this strategy is not available in the existing works. Therefore, in the first part of this paper, we analyze the performance of cooperative STBC with the AF strategy. Exact bit error probabilities (BEP) are derived in closed form for three existing protocols. Since the AF strategy simply forwards the signals at the relays, the noise at the relay is also forwarded to the destination, and it degrades the received signals from both the relay and the source, due to the receiver structure of STBC. In the second part of this paper, we examine the effect of the forwarded noise and propose a condition under which the relay should stop forwarding the signals. Based on this condition, adaptive forwarding schemes for cooperative STBC are proposed. The performances of these schemes are studied and the exact BEP's are also obtained in closed form. Finally, the energy efficiencies of these adaptive schemes are discussed.