Resumen de Energy-efficient routing protocols for ad hoc underwater sensor networks
Underwater Wireless Sensor Networks (UWSNs) are subjected to a multitude of real-life challenges. The use of UWSNs offers great advantages in many automatic observation services such as water monitoring (ocean, sea, etc.) and registering of geological events (landslides, earthquakes). For obvious reasons, maintaining adequate power consumption is important, and critical in case of nodes far from the sink node (called gateway or GW), which affects the system¿s overall energy efficiency. These wireless sensors gather and route the data to the onshore base station through the GW node at the sea surface. However, finding an optimum and efficient path from the source node to the GW is challenging. The common reasons for the loss of energy in existing routing protocols for underwater are (1) a node death due to battery drainage, (2) packet loss/collision which causes re-transmission and hence affects the performance of the system, and (3) inappropriate selection of relay sensor node for forwarding data. To address these issues, a new energy-efficient packet forwarding scheme using fuzzy logic is proposed. The proposed protocol uses three metrics: number of hops to reach the gateway node, number of neighbors (in the transmission range of a node), and the distance (or its equivalent received signal strength indicator, RSSI) in a 3D UWSN architecture. To cope with these problems, the use of a routing protocol is incredibly crucial. We propose a routing technique that adapts to changes in the network topology, avoiding multiple retransmissions that would affect its overall performance. This protocol is energy-efficient and is implemented using a fuzzy analytical hierarchical process (FAHP) under multi-criteria decision-making (MCDM) to make an intelligent routing decision based on objectives, criteria, and alternatives. To select the next node on the route, several comparison matrices are used: the number of hops, distances to the GW node, and the number of neighbors. Since there are a number of sensor nodes that needs to forward or relay the data toward the GW node, the election of the relay or forwarding node become important to minimize the end-to-end delay. The node which will be closer to the GW node will have more chances to forward the data however, several more parameters need to be considered like the number of hops and the number of neighbors. In this thesis, we selected the relay node based on fuzzy techniques and chose the weight criteria of the sensor node which will be selected as the forwarding node. The node with the highest weight shall be chosen as the relay node. The selection criteria, in this case, is that the sensor node which has less distance, the least number of hops, and the least number of neighbors will have the priority to act as a relay node. The results show that the proposed setup performs better than existing UWSNs routing schemes such as SPRINT and RECRP. The use of the fuzzy technique in UWSN will lead to future AI (Artificial Intelligence and Neural Networks for self-decision-making of the sensor nodes).
