Wireless Sensor Networks (WSNs) are increasingly used in different application fields thanks to several advantages such as cost-effectiveness, scalability, flexibility and self-organization. A hot research topic concerns the study of algorithms and mechanisms for reducing the power consumption of the nodes in order to maximize their lifetime. To this end, this paper proposes an approach based on two fuzzy controllers that determine the sleeping time and the transmission power. Simulation results reveal that the device lifetime is increased by 30% with respect to the use of fixed sleeping time and transmission power and by 25% with respect to a state-of-the-art work that adjusts only the sleeping time.
In wireless sensor network, it is essential to find effective means for power control of randomly distributed nodes. In this paper, based on diverse receiving QoS parameters, a fuzzy algorithm for peer to peer power control of wireless sensor nodes is proposed. Simulation results show that the proposed algorithm reduces packet error rate (PER) and prolongs survival time of network, compared with fixed transmission power method. Thus, this fuzzy algorithm could realize reliable data transmission with low power consumption.
We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero.