Quantidade mínima e alocação-regulação ótima de nós sensores móveis para uma cobertura circular completa da RSSF híbrida

Abstract

Coverage is a measure of quality of service in wireless sensor networks (WSNs), and is essential for monitoring a delimited region. This work addresses the dynamic coverage problem of a hybrid WSN, proposing a methodology consisting of two complementary methods. The first method aims to determine the minimum quantity of mobile sensor nodes required to ensure full coverage of the monitoring region. This approach is based on a theoretical framework composed of assumptions, propositions, theorems, and corollaries, considering the sensor detection circles, the monitored region, and the agent displacement circle. The model ensures full network connectivity and presents flexibility in dealing with agent failures. The second method proposes an optimal DLQT-DLQR coverage control scheme, based on the discrete algebraic Riccati equation (DARE), with the objective of optimizing the displacement and regulation of dynamic nodes in their target positions. The methodology ensures coverage without holes (gaps) and without connectivity losses among nodes, minimizing the displacement time of mobile agents and avoiding collisions, due to the preservation of the order of nodes along the displacement circle. The monitored environment is modeled as a circular region, with a static sensor node in the center, while the dynamic sensor nodes are allocated in a circumference with a radius smaller than the coverage region. The proposed solution allows the efficient monitoring of hostile environments, especially aquatic ones, contributing to environmental preservation, reducing costs with idle sensors, and increasing the operational efficiency of the WSN. A comparative analysis with the method based on Voronoi diagrams is performed, highlighting the need for algorithms capable of calculating the desired positions of the agents to ensure flawless coverage. The proposed method meets this requirement by determining the target positions of the agents. In addition, the influence of the variation of the coverage radius on the number of mobile sensor nodes for full monitoring is analyzed and a comparison is made with a rectangular monitoring area. Finally, the performance of the proposed allocation and regulation control is evaluated in relation to classical controllers, such as proportional (P) and proportional integral (PI), in the time domain with figures of merit