A major challenge in wireless sensor networks research is energy efficiency. In the intermittent receiver-driven data transmission (IRDT) protocol, which aims at saving energy, communication between two nodes commences when multiple receiver nodes transmit their own IDs and the sender nodes receive them. This protocol can be used to construct a mesh network which is robust against node failure and wireless channel fluctuations. In our work, we improve this protocol by implementing a collision avoidance method for control packets. First, we refer to the probability of control packet collision as a function of the intermittent interval. We then introduce procedures to determine the interval which decreases or minimizes this probability. Afterwards, we include a data aggregation mechanism into IRDT to reduce data transmission frequency and the occurrence of control packet collisions. Through computer simulation, we show that IRDT can offer greater reduction of the average energy consumption compared with RI-MAC and X-MAC, especially at small loads, and we also demonstrate that IRDT with collision avoidance for control packets can attain higher performance than the original IRDT. This method ensures a packet collection ratio of more than 99% and an average energy consumption 38% lower than that of EA-ALPL and 90% lower than that of the original IRDT.

In wireless sensor networks, localization systems use data from sensors which receive signals from moving targets, measure RSSI, and translate RSSI into the distance between sensor and target. We consider a localization system that gives an error measurement model of distance and introduce a relationship between the number of data and accuracy. Extending the lifetime of a system is needed to save the energy of sensors and collect the necessary data. In this paper, we propose an efficient data collecting technique to get the accuracy required for the applications while saving energy. We verify that our proposal can efficiently collect necessary data to get accuracy in cases of random sensor placement.

Improving the scalability and robustness of wireless sensor networks is an important task, and much research on self-organization has been conducted toward this end. However, desired behavior is not yet guaranteed in much larger networks based on pure self-organization. In this article, we propose a controlled potential-based routing protocol implementing a novel controlled self-organization scheme that also allows for external control. The scheme obtains close-to-optimal network behavior by this external control which controls a part of nodes in the network. We show that global traffic flow can be controlled through simulation experiments with a multi-sink sensor network. For example, traffic loads can be equalized among heterogeneously distributed sink nodes, and load balancing among the relay nodes based on remaining energy can bring an approximate four times extension of network lifetime. The proposed method is furthermore robust to message loss and resilient to failure of the sink node.

In this paper, we focus on the calling behavior of Japanese tree frogs, which make calls alternately with their neighbors in order to increase the probability of mating. This behavior can be applied in phase control which realizes collision-free transmission scheduling in wireless communication. We propose a self-organizing scheduling scheme inspired by this frog calling behavior for reliable data transmission in wireless sensor networks. Simulation results show that our proposed method for phase control is capable of reducing data transmission failures and improves the data collection ratio up to 24% compared to a random transmission method.