Wireless transmission using cooperation on demand

Mobile users with single antennas can still take advantage of spatial diversity through repetition based cooperative transmission. In this paper, we consider a scheme in which the cooperation is triggered only if the source–destination channel is of an unacceptable quality. Therefore, the destination selects one relay out of a decoding set of relays for cooperation. We analyze the end-to-end outage probability in slow and fast fading environments and we evaluate the usefulness of relaying when the source acts blindly and ignores the decision of the selected relay whether it may cooperate or not. The performance in both environments are evaluated through analysis and simulations in terms of end-to-end outage probability and the number of active relays. Some selected performance results show that some selected computer simulation based results coincide with our analytical results.