Adaptive Amplify-and-Forward Cooperative Channel

In this work, we propose an amplify-and- forward (AF) protocol based on a new selection criterion, a function of the instantaneous capacities of all possible transmission schemes (with or without cooperation). The outage probability and the simulation results show that the new Adaptive AF protocol has better performance than the best known AF protocol (NAF). Moreover, this protocol solves the problem of the bad performance of NAF at low SNR. We also make a relay-selection to obtain a better diversity-order and then better performance.