|Texas Tech University
|broadcast protocol; ad hoc network; wireless sensor network; geometric broadcast; transitional region; wireless link quality.
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Rapidly proliferating the cloud, social media, and wearable devices and reducing the cost of processing power, storage, and bandwidth are fueling explosive development of Internet of Things (IoT) applications and services in major domains, e.g., personal and home, enterprise, utilities, and mobile. It is envisaged that wirelessly connected smart and low-power devices under the IoT will become a part of ubiquitous communication and computing infrastructure, and will further change life as we live it. To realize this vision, broadcast operations still play an essential role in scalable information dissemination to enhance information accessibility and availability. However, a blind broadcast followed by a series of unconditional forwarding operations is inefficient and even harmful, because it can cause redundant retransmissions and packet contentions and collisions. The redundant retransmissions can also negatively affect the communication performance, such as the network lifetime. In addition, radio links often tend to be unreliable and unpredictable because of the signal propagation effects, such as path loss, shadowing, or multipath propagation. The time- and space-varying link qualities can significantly affect the performance of communication protocol and algorithm that can be embedded in the link or network layer. The overall objective of this research is to design, analyze, and evaluate scalable and realistic broadcast strategies in resource-constrained wireless networks. We investigate three major research issues. First, we propose two pseudo geometric broadcast schemes, called enhanced ad hoc broadcast protocol with target forwarding nodes (EBP) and node distribution sensitive broadcast (NDS), and analyze their performance in wireless sensor networks (WSNs). Second, we conduct a comprehensive performance comparison of pseudo geometric broadcast schemes and its multi-dimensional analyses in terms of node density, network size, and computational overhead in WSNs. Third, we propose a transitional region aware broadcast scheme, called TCast, in the presence of variable wireless link qualities. This is a stateless broadcast protocol and its simple mathematical analysis is also suggested. We develop a customized discrete-event driven simulator using the OMNeT++, implement other competitive broadcast schemes, and show the advantages of proposed techniques through extensive simulation experiments and mathematical analyses. In addition, we discuss potential enhancements of the proposed techniques and future research directions. Advisors/Committee Members: Chen, Yong (committee member), Shin, Michael (Eonsuk) (committee member), Zhuang, Yu (committee member), Lim, Sunho (Committee Chair).