On the Performance of Cooperative Diversity in Infrastructure-Based Networks with Two Relays

In this paper, the performance of four cooperative relaying schemes, which are classified by requiring a quantity of feedback information, is evaluated in the high SNR region and is compared with that of MIMO relaying schemes with two antennas. For amplify-and-forward (AF) relay, all schemes except the second hop selection scheme provide the second order diversity gain in high SNR region. For decode-and-forward (DF) relay, despite using more channel information, the coherent BF scheme does not offer the second order diversity. A system level simulation is evaluated to analyze the effects of user distribution in terms of the average capacity. For AF relay, the capacity of the cooperative relaying model is higher than that of the MIMO relaying model as about 0.2 bps/Hz. For DF relay, the MIMO relaying model provides capacity gain about larger than 0.3 bps/Hz for the coherent beamforming and the Alamouti-based scheme since the effect of array gain at relay for these schemes is more dominant factor to increase the capacity compared with the effect of reducing path loss.