Cooperative MIMO and relay association strategy

In wireless distributed networks where multiple antennas can not be installed in one wireless node, cooperative relay and cooperative Multi-Input Multi-Output (MIMO) techniques can be used to exploit the spatial and temporal diversity gain in order to reduce the energy consumption. The simplicity and the energy efficiency of cooperative Multi-Input Single-Output (MISO) and relay techniques is very useful for the energy constrained Wireless Sensor Networks (WSN). If under ideal conditions cooperative MISO has been proved to be better than relay, the latter is a better solution when transmission synchronization errors occur. In this context, an association strategy of these two techniques is proposed, in this paper, in order to exploit simultaneously the advantages of these two techniques. The principle of this association strategy is that a cooperative MIMO technique is employed at multiple relay nodes to retransmit the signal by using a MISO transmission in one transmission phase instead of multiple transmission phases of the traditional parallel relay technique. Performance, energy consumption and transmission delay of this association technique, including the comparison with the cooperative MISO and relay techniques, are investigated in this paper.