BER and diversity order analysis of distributed Alamouti's code with CSI-assisted relays

This paper focuses on average bit error rate (BER) and diversity order analysis of distributed Alamouti's code in dissimilar cooperative networks with channel state information (CSI)-assisted relays. We first assume that the relays adopt the amplifying coefficient. A lower and an upper bounds of the average BER of the distributed Alamouti's code are derived. Then we show that the distributed Alamouti's code only achieves diversity order one when the relays use the amplifying coefficient. Furthermore, in a general cooperative network with more than two relays, we show that the distributed space-time codes only achieve diversity order one as well when the amplifying coefficient is used at the relays. To resolve this problem, we propose a new amplifying coefficient and it makes the distributed Alamouti's code achieve the full diversity order two.