Starfish Routing to Maximize Lifetime of Sensor Networks with Mobile Sink

Abstract

Nowadays, the development of smart cities has become a dire necessity to improve the quality of human life. Wireless sensors and necessary information and commu- nication technology (ICT) infrastructures are the fundamental building blocks of smart cities. The number of connected sensor nodes worldwide is jumping to 125 bn by 2030. We are continuously witnessing the rapid development of sensor net- works for a vast range of real-time applications. It becomes challenging to collect data on time from these versatile sensor nodes. Moreover, the energy criticality of these autonomous nodes is a crucial constraint to maximize lifetime of sensor net- works. Existing works in the literature suffer from imbalance energy consumption, reducing the network lifetime, and many of those don't explore efficient methods for on-time data collection from a network having obstacles. In this dissertation, we aim to explore real-time data routing and collection strategies both for obstacle-free and obstructed networks. At rst, we focus on de- veloping a novel data routing backbone to maximize network lifetime in an obstacle- free sensor network. The rst contribution of this thesis is introduction of a Star sh routing (SFR) backbone for sensor networks with a mobile sink that spreads the backbone nodes over the different regions of the network in such a manner that any source node can directly access at least one of the backbone nodes. The con-struction of the SFR backbone is motivated by the water vascular system of a sea Star sh. Following this, the backbone nodes are placed on a central ring-canal that helps to alleviate the hot-spot problem around the network center, and on the radial-canals that facilitate faster data delivery towards the mobile sink from any corner of the network. These canals jointly help to distribute data routing loads and uniform energy consumption throughout the network, resulting in extending network lifetime. The second contribution of this thesis is the development of a data collection strategy for a mobile sink in an obstructed network to reduce data delivery delay and to maximize network lifetime. Due to the presence of obstacles (e.g., building, forest, etc.) and heterogeneous data generation rates, the data collection strate- gies become more challenging and have not yet been well-studied. Therefore, it necessitates developing a data collection schedule to maximize network lifetime for real-time applications in an obstructed network. A high-speed data routing back- bone and data collection schedule of a mobile sink in an obstructed network have been developed as a mixed-integer linear programming problem that maximizes network lifetime while meeting delay-deadline requirements of real-time applica- tions. It nds an optimal travel plan of the mobile sink and corresponding sojourn durations at sojourn locations. The proposed Star sh data collection schedule also guarantees loop-free travel scheduling among the sojourn locations, ensuring bal- anced energy consumption throughout the network. Finally, the performances of these works have been carried out in Network Simulator-2, and signi cant improve- ments are observed for both obstacle-free and obstructed sensor networks in terms of network lifetime, end-to-end data delivery delay, throughput, etc. compared to the state-of-the-art works.