Doctor of Philosophy (Ph.D.)
Degree Granting Department
Hüseyin Arslan, Ph.D.
Nasir Ghani, Ph.D.
Ismail Uysal, Ph.D.
Jay Ligatti, Ph.D.
Tamer Khattab, Ph.D.
5G, Beam-Space, Directional Modulation, Multiple-Input-Multiple-Output (MIMO), Non-Orthogonal-Multiple-Access (NOMA), Physical-Layer-Security
The emerging advances in wireless communications make it an essential component of our everyday life. Moreover, the current research aims towards involving wireless communications in health monitoring applications, which helps medical personnel to remotely keep track of the development of the condition of their patients. Such information is considered highly sensitive and may cause significant harm if acquired by an adversary. The wireless environment has a broadcast type of nature, where the emitted electromagnetic waves spread all over the surrounding area of the transmitting antenna. This broadcast nature raises a considerable concern about the secrecy of this sensitive information while being transmitted over-air.
On another side, the advancement in computer algorithms makes the currently adopted
cryptographic algorithms prone to multiple attacks, which facilitate the access to the initially transferred
information. In such a context, another approach is required to avoid the exposure of the
information. Concealing the information at the physical layer of communications systems became
of enormous interest to overcome the shortages in cryptographic approaches. One feature of
the physical-layer is the availability of multiple transmit/receive antennas. The multiple antennas
structure allows us to manipulate the spatial construction of the transmitted signals. The spatial
construction of the signal allows us to limit the area, where any receiver in the system can detect
Our Studies focus on providing both secure and reliable communications, and we can characterize
the studies in the following approaches,
- Location-Based Secure Communications: We established the ground for multiple directions
transmission techniques, where each transmission direction carries an independent set of
information. Using this ground, we proposed multiple approaches that limit the availability
of the information to the small area surrounding the target receiver.
- Complexity Reduction for Multi-Direction Systems: With the increase in the physical resources,
the complexity of the system increases. We proposed a simplified structure for the
system that reduces the complexity from three orders of magnitude to a single order of magnitude.
Moreover, we introduced a limited feedback scheme, that reduces the overhead used
in the system.
- Enhancing the System Capacity: Due to the increase in the number of wireless users, higher
data transmission rates need to exist. Using Directional transmission, we were able to intelligently
allow the overlap of different data streams on the same available physical resource.
This overlap allows the reuse of the same resource for different users, and increase
the achievable transmission rates.
Scholar Commons Citation
Hafez, Mohammed A., "Enhancing Secrecy and Capacity of Wireless Systems Using Directive Communications" (2019). Graduate Theses and Dissertations.