Date of Award

Spring 2022

Project Type


Program or Major

Electrical and Computer Engineering

Degree Name

Doctor of Philosophy

First Advisor

Nicholas J. Kirsch

Second Advisor

Nicholas J. Kirsch

Third Advisor

Se Young Yoon


Electromagnetic spectrum, as a limited resource, is prone to scarcity due to the astronomical growth in demands for ubiquitous wireless connectivity in the past few decades. Meeting such an ever-growing demand is contingent upon optimizing the spectrum utilization. In this context, dynamic spectrum access policies, such as spectrum sharing, are promising solutions to mitigate the spectrum gridlock. Spectrum sharing networks are allowed to operate on the licensed frequency bands as the secondary users of the spectrum provided that the licensed primary network is protected from any disruptive interference due to the coexistence. The stringent constraints on the secondary network for curbing the inflicted interference significantly limits of reliable communication. To resolve this issue, a relaying station can be employed to extend the coverage of secondary connectivity.

To improve the efficiency of the conventional spectrum sharing relay networks, the emerging technologies such as free space optical (FSO) communication, multiple-input multiple-output communication, energy harvesting and buffer-aided relaying can be incorporated. It is envisaged that the amalgamation of such technologies would provide us with a promising solutions to overcome the potential electromagnetic spectrum gridlock. My research works in this thesis is aimed to design communication protocols for such novel network models for spectrum sharing relay networks. The major contributions of this thesis revolve around designing communication protocols, resource allocation, and analysis of the proposed frameworks for the spectrum sharing and conventional cooperative communication networks.

In this thesis, I will introduce the first network model for the mixed RF/FSO buffer-aided backhauling network with underlay spectrum sharing access for the RF channels; I will introduce the first queue-aware antenna allocation scheme for the buffer-aided in-band full-duplex relaying networks; and I will introduce the first adaptive load balancing mechanism for the mixed RF/FSO buffer-aided relaying networks.

Available for download on Thursday, February 02, 2023