Date Added: Aug 2009
The authors consider wireless Multiple-Input-Multiple-Output (MIMO) communication between nS no-cooperating source antennas and nD fully cooperating destination antennas. Let them suppose the source antennas are either far apart or shadowed from the destination antennas. The installation of intermediate nodes that relay the source signals to the destination (multi-hop) is well known for being an efficient means for improving the energy-efficiency of the communication system in this case. In the resulting network, the signals traverse L clusters containing nR relay antennas each, before they reach the destination antennas. The relay antennas forward the signals by performing an amplify-and-forward operation.