Date of Award

5-8-2021

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Systems Engineering

First Advisor

Seshadri Mohan

Abstract

Motivated by the fifth generation of mobile networks, the Internet of Things (IoT) has emerged as one of the most promising and interesting technologies that are currently evolving IoT, which is expected to be deployed on a large-scale beyond 2020. However, this technology's main drawback is the security issue due to the variety of network access technologies and the wireless medium's nature. Thus, in the last decade, considerable efforts were expended to address this issue. However, much of the work has focused on the data link and upper layers, and much less attention has been given to the physical layer security. In this work, we address the physical layer security of IoT. First, we provide a survey of the stochastic geometry approach to ensuring the security of IoT. In this chapter, we define and investigate the use of stochastic geometry, the secrecy graph, and the Poisson point process in analyzing the security of the wireless physical layer of the IoT. Second, we propose to enhance the physical layer security of the IoT by using a technique called information passing and interference addition. This chapter aims to increase the achievable secrecy rate by letting the legitimate transmitter find an alternative route to the fusion center to achieve a higher secrecy rate than the direct route. Third, in this chapter, the conventional frequency hopped spread spectrum (FHSS), uncoordinated frequency hopping (UFH), and the message-driven frequency hopping (MDFH) have been simulated and analyzed for bit error rates against single and multiband disguised jamming attacks. Those schemes are not feasible for IoT applications due to the lack of computation capability, size, and energy consumption. Because of that, we designed and simulated a new frequency hopping scheme that takes into consideration the IoT node's limitations and, at the same time, maintains a satisfying bit error rate. Finally, securing the OFDM physical layer remains a challenge. Nevertheless, the OFDM transceiver could not be directly built in the IoT nodes without careful modification due to the node's lack of space, cost, and power. Thus, in this chapter, we propose an innovative way to cope with the problems by designing a device to simplify the communication between the base station and the IoT nodes. The proposed device has two main functions: first, to receive the composed signal from the OFDM transceiver and convert it to parallel multicarrier signals for transmission and vice versa. The second is to apply a suitable frequency hopping technique to secure the communication between the base station and the proposed device. The frequency hopping technique is used to protect the nodes from jamming and eavesdropping attacks.

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