In this paper, the performance of the Wireless Sensor Network (WSN) using fixed relay nodes and Multiple-Input Multiple-Output (MIMO) technology was evaluated based on the correlated channel capacity of MIMO system and the number of sensor node served by the system. Moreover, the performance evaluation of the proposed algorithm, which is used to find the optimum distance to place the relay nodes from sink node, is done not only with AF relaying and spatial correlation effect, but also with Decode-and-Forward (DF) relaying scheme. The results show that the relay gain (a ratio between the maximum number of sensors satisfying the required channel capacity in 7-cell topology to the number of sensor nodes in sink cell) is affected strongly by the spatial correlation at high required channel capacity but little at low required channel capacity. The results also show that the relay gain can be improved remarkably by using the DF relaying scheme, and that the validity of the proposed algorithm holds for any relaying scheme, spatial correlation effect and different antenna size.

The Wireless Sensor Network (WSN) uses autonomous sensor nodes to monitor a field. These sensor nodes sometimes act as relay nodes for each other. In this paper, the performance of the WSN using fixed relay nodes and Multiple-Input Multiple-Output (MIMO) technology necessary for future wireless communication is evaluated in terms of the channel capacity of the MIMO system and the number of sensor nodes served by the system. Accordingly, we propose an optimum topology for the WSN backbone named Connected Relay Node Double Cover (CRNDC), which can recover from a single fault, the algorithms (exhaustive search and other two approximation methods) to find the optimum distance to place the relay nodes from sink node, and the height of the sink and relay nodes to be placed by using the pathloss model. The performances of different MIMO-WSN configurations over conventional WSN are evaluated, and the direct relationship between relay position and minimum required channel capacity are discovered.