Sensor nodes within networks are often grouped to participate to a common processing task. Cooperative diversity is a technique that exploits groups of sensor node randomly placed to cooperatively relay a common received signal toward a destination with the goal to combat severe attenuation or disconnections of the signal strength.
In recent years, cooperative diversity has received attention for cellular radio systems and ad-hoc wireless networks. Such systems, however, are usually equipped with high processing capability. On the contrary, the nodes of a WSNs have limited memory and power capabilities and are usually deployed in unfriendly environment, where recharging and maintenance is not possible.
In this thesis, we investigate the problem of power control of nodes performing cooperative diversity. Speciﬁcally, we study the problem of minimizing the power consumption of the sensor nodes transmitters while guaranteeing a minimum quality of the signal at the data collector. After studying the most relevant algorithms existent in literature for had-hoc networks, we propose an sub-optimal algorithm suitable for nodes equipped with low computational capabilities. We implement a WSNs performing cooperative diversity with Omnet++, where the network simulator includes the sub-optimal solution. Numerical results show that for the set of parameters of practical interest, our solution exhibits good performance for low correlated channel links, while the increase of relaying nodes ensures a decreasing of total power consumption.
2005. , 105 p.