Data acquisition techniques for next generation wireless sensor networks

Graduation date: 2012The meteoric rise and prevalent usage of wireless networking technologies for mobile\ud communication applications have captured the attention of media and imagination of\ud public in the recent decade. One such proliferation is experienced in Wireless Sensor\ud Networks (WSNs), where multimedia enabled elements are fused with integrated\ud sensors to empower tightly coupled interaction with the physical world. As a promising\ud alternative to antiquated wired systems and traditional WSNs in a multitude of novel application\ud scenarios, the newly renovated WSNs have inspired a wide range of research\ud among which investigation on data acquisition techniques is a fundamental one. In this\ud dissertation, we address the problem of data acquisition in next generation WSNs. As\ud wireless sensors are powered with limited energy resources while they are expected to\ud work in an unattended manner for a long duration, energy conservation stands as the\ud primal concern. Also, to enable in-situ sensing in different rate-constrained applications,\ud routing decisions should care about the medium access feasibility of achievable\ud end-to-end data rates. Driven by the fact, we first design cross-layer medium contention\ud aware routing schemes for rate-constrained traffic in single-channel WSNs that maximize\ud network lifetime. Three sufficient conditions on rate feasibility, referred to as\ud rate-based, degree-based, and mixed constraints, are incorporated into the routing formulations\ud to guarantee the practical viability of the routing solutions. Next, with the aim\ud to mitigate interference and hence to enhance network capacity, we extend our work\ud by proposing energy and cross-layer aware routing schemes for multichannel access\ud WSNs that account for radio, MAC contention, and network constraints. In that context,\ud we first derive three new sets of sufficient conditions that ensure feasibility of data\ud rates in multichannel access WSNs. Then, utilizing these sets, we devise three different\ud MAC-aware routing optimization schemes, each aiming to maximize the network\ud lifetime while meeting data rate requirements of end-to-end flows. Finally, we perform\ud extensive simulation studies to evaluate and compare the performance of the proposed\ud routing approaches under various network conditions. So far works are done in milieu\ud of WSNs with both fixed access node and sensor nodes. In the subsequent part\ud of the dissertation, we present the continuation of our work focusing on reliable data\ud acquisition in Mobile WSNs for a promising application namely free-ranging animal\ud tracking/monitoring. To accomplish that goal, we concentrate on providing sufficient\ud conditions on access-point density that limit the likelihood of buffer overflow. We first\ud derive sufficient access-point density conditions that ensure that the data loss rates are\ud statistically guaranteed to remain below a given threshold. Then, we evaluate and validate\ud the derived theoretical results with both synthetic and real-world data