Algoritmi pentru reducerea volumului de date pentru a ameliora eficiența energetică a rețelelor de senzori fără fir cu transmisie directă sau organizate în clustere / Data reduction algorithms to improve the energy efficiency of single hop or cluster based wireless sensor networks

Wireless sensor networks (WSNs) are a popular research topic especially due to issues such as power consumption, routing algorithms, and lifetime. Despite its shortcomings, WSN has a wide range of applications. One of the primary goals is to extend the lifetime of WSNs. Therefore, the main aim of this thesis is to improve the WSN performance in terms of lifetime. To do so, first, an overview of WSN was given. The limitations of the studies that have been done so far and what more research could be done are analyzed. Second, I used MATLAB simulations to investigate the influence of data reduction techniques on the functionality of WSN using a couple of different datasets. Third, I have investigated the impact of different data packet sizes on the performance of cluster based WSN. According to the findings of this study it is advised that routing protocols be integrated with data reduction strategies to obtain high performance. Finally, I have developed a hybrid data reduction algorithm (I{DRA) for cluster based WSN. HDRA simultaneously considers data reduction and routing to reduce the sensor node's energy consumption. Using an artificial dataset, both the HDRA method and the cluster-based protocol were evaluated by observing network lifetime. According to the obtained results, the average number of transmissions considering four scenarios from the point of view of the network topology and considering temperature (T), humidity (H) and temperature/humidity (T/H) sensor types was 17550 (T),21250 (H), and 13700 (T/H) respectively. In contrast, in case of the simple cluster-based routing protocol the average number of transmitted packets for all scenarios reached up to 10300. The proposed algorithm improves network longevity to 48550 rounds, compared to 10750 rounds for the cluster-based protocol working alone