Graduation Year

2020

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Electrical Engineering

Major Professor

Huseyin Arslan, Ph.D.

Committee Member

Gokhan Mumcu, Ph.D.

Committee Member

Nasir Ghani, Ph.D.

Committee Member

Selcuk Kose, Ph.D.

Committee Member

Srinivas Katkoori, Ph.D.

Keywords

Beamforming, Milimeter-Wave, Multiplexing, Narrow Beam

Abstract

The growing interest in data-hungry wireless applications of mobile devices has led the cellular industry to look for new frequencies and new techniques for utilization of next-generation wireless technologies. As millimeter-wave (mmWave) communication becoming a promising solution, It can provide greater bandwidth and higher data rates in future radio access. While in the hostile environment of mmWave bands, the signals suffer from high propagation loss, the smaller wavelengths of mmWave frequencies make it possible to practically pack a large number of antennas with reasonable form factors. Thus, mmWave communication can provide directional transmission with high gain antenna arrays to penetrate the hostile environment. Digital, analog, and hybrid beamforming are commonly used methods to form directional transmission using antenna arrays. However, as the Millimeter-wave (mmWave) components are expensive, even simple analog beamforming approach would need phase shifters, control circuits, and may still require an expensive circuit design. The increase on the array size, also complicates the hardware and algorithms to control the generated beams which also require more advanced resource allocation including beam-user association.

In this dissertation, first, data rate and energy efficiency performance of mmWave wireless communication systems consisting of a new lens antenna subarray (LAS) based hybrid multiple-input-multiple-output (MIMO) architecture is investigated. LAS architecture simplifies hardware requirements and lowers the cost by reducing the number of phase shifters while potentially maintaining near identical beam-steering and gain capabilities with respect to the traditional hybrid MIMO architecture (TA). The LAS architecture degenerates into TA or single lens antenna array architecture (SLA) when the lens diameter of the subarray is reduced or enlarged, respectively. Second, dynamic sidelobe multiplexing (DSM) algorithm is proposed to overcome restrictions that comes from limited number of radio-frequency (RF) chain usage. The proposed multiplexing technique precodes the transmitted data over transmitter beams in order to open up a new path to the receiver. Therefore, the proposed method provides an opportunity to exceed the limits of conventional hardware usage in beamspace MIMO. Third, an algorithm for joint optimization of antenna parameters with load balancing is presented to distribute users to cells while optimizing the antenna parameters. The proposed approach does not only change the serving range of each cell but also re-assign users to cells for effective system capacity to provide maximized resource allocation. Fourth, another resource allocation problem is investigated in Manhattan grid layout mobility performance of Macrocell-assisted small Cell concept. Fifth, perturbed antenna array geometries are investigated for a novel authentication approach which introduces an identity to formed beams. Sixth, RF domain Doppler emulator, which is compact and easy to control, is presented to measure signal characteristics under frequency dispersive channel conditions for swift evaluation of developed algorithms.

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