Defesa de Doutorado – Suelen Macedo Laurindo – 27/8/2021

12/08/2021 21:24
Defesa de Tese de Doutorado
Aluna Suelen Macedo Laurindo
Orientador

Coorientador

Prof. Ricardo Alexandre Reinaldo de Moraes, Dr. – PPGEAS/UFSC

Prof. Carlos Barros Montez, Dr. – DAS/UFSC

Data

 

27/8/2021  9h  (sexta-feira)

Videoconferência (meet.google.com/xzi-zkjy-icn)

 

 

Banca

Prof. Ricardo Alexandre R. de Moraes, Dr. – PPGEAS/UFSC (presidente);

Prof. Daniel Gouveia Costa, Dr. – DTEC/UEFS;

Prof. Richard Demos de Souza, Dr. – EEL/UFSC;

Prof. Marcelo Ricardo Stemmer, Dr. – DAS/UFSC;

Prof. Érico Meneses, Dr. – UFPI.

Título Relay Selection Technique Applied to Wireless Sensor Network: the ORST Approach
Abstract: Wireless sensor networks (WSNs) are increasingly prevalent in everyday life (for example, in healthcare, smart cities, smart agriculture, Industry 4.0, and the sustainable use of terrestrial ecosystems), as they can facilitate daily activities and improve quality of life. However, in all these applications, the reliability of communication remains a challenge due to the nature of wireless communication channels, which are subject to electromagnetic noise and obstacles between nodes that can attenuate or reflect the signal. To minimize these problems, cooperative diversity techniques and retransmission mechanisms are efficient strategies that can be applied. In cooperative diversity techniques, several nodes are selected as relays and are responsible for transmitting both their own data and data from other nodes that have been previously stored. Relay selection is a critical step that may affect the quality of transmission, and it is therefore important to find the most appropriate selection criteria for the operation of the network. In addition, network coding techniques are widely used retransmission mechanisms in which intermediary nodes act upon the retransmitted messages and modify them using specific mathematical coding techniques. Network coding techniques are a promising solution for minimizing transmission delay, balancing the network load, and improving the network throughput. In this context, this thesis examines the limitations on reliable communication in WSNs by treating the communication in a holistic way. As a contribution in this thesis, we highlight: (i) a systematic review on relay selection techniques; (ii) the proposal and validation of a new technique for selecting relay nodes, which we call ORST (Optimized Relay Selection Technique); (iii) an analysis of the parameters used in the selection of relay nodes in the ORST technique; (iv) an analysis of the solutions used in the relay selection problem of the ORST technique; (v) a systematic review of network coding techniques; (vi) the proposal of a network coding technique together with the proposal of four retransmission mechanisms, three of which consider the network coding technique and one do not use network coding; and finally, (vii) an analysis of the operation of a WSN when using the ORST technique and retransmission mechanisms, with and without network coding. To evaluate the cooperative selection technique and the retransmission mechanisms, the network simulation tool OMNeT++ and the WSN framework Castalia were used. The initial assumption underlying this research work was that the use of the proposed relay selection technique in conjunction with a retransmission mechanism that used network coding would improve the communication reliability of a WNS; however, the simulation results showed that when the proposed relay selection technique was used, retransmission without network coding was a better solution.