Μελέτη προσαρμοστικών τεχνικών μετάδοσης πληροφορίας σε ασύρματα δίκτυα αισθητήρων
Μπράβος, Γεώργιος Ν.
Wireless Sensor Networks consist of small sensor nodes, which are able to communicate with each other, to sense diverse data from the environment and to retransmit it to the rest of the network. The sensed data depends on the sensor embedded in the nodes, and the variety of available sensors enables these networks to measure humidity, temperature, to identify movement, to watch patients’ health status, for surveillance purposes and many other applications. In a WSN, the nodes may preserve moving abilities or be static. It is also possible that they have to operate in dangerous or hostile environments. In most cases, their operation is based on small batteries, which is difficult to replace. Hence, when a node remains out of battery, it usually goes out of the network. Therefore, the design of such networks is mainly based on reducing energy consumption, in order to increase their lifetime. They mainly focus on the improved performance in terms of energy efficiency, but quality of services is also considered. In order for this study to be completed, firstly some essential models have been created, which mainly have to do with the network topology, the channel status, the energy consumption estimation and the simulation. Therefore, exact models have been examined, and used throughout the study for the design and performance estimation of the presented data transmission techniques. Based on the above study, a combined routing – adaptive transmission power algorithm has been developed. The proposed algorithm is named Energy – DElay Minimization (EDEM) and the results after its implementation indicated that it significantly decreases the energy needed for the transmission of a given data amount, increasing thus the lifetime of a WSN.