Engineering Commons^™

Novel Estimation And Detection Techniques For 5g Networks, Anas Saci

Electronic Thesis and Dissertation Repository

The thesis presents several detection and estimation techniques that can be incorporated into the fifth-generation (5G) networks. First, the thesis presents a novel system for orthogonal frequency division multiplexing (OFDM) to estimate the channel blindly. The system is based on modulating particular pairs of subcarriers using amplitude shift keying (ASK) and phase-shift keying (PSK) adjacent in the frequency domain, which enables the realization of a decision-directed (DD) one-shot blind channel estimator (OSBCE). The performance of the proposed estimator is evaluated in terms of the mean squared error (MSE), where an accurate analytical expression is derived and verified using Monte Carlo …

Energy-Efficient Multicarrier And Multicarrier-Cdma Systems, Moftah Ali

Electronic Thesis and Dissertation Repository

Design, analysis, and performance of Multicarrier (MC) and Multicarrier-Code Division Multiple Access (MC-CDMA) systems are considered. Specifically, Multicarrier Modulation (MCM) such as Orthogonal Frequency Division Multiplexing (OFDM) is used in these systems with emphasis on energy efficiency. These systems are examined for their performances over frequency-selective and frequency-non-selective channels. Methods are proposed for reduction of energy costs of an OFDM system. They are: i) Clipping (CL) based on symbol statistics; ii) Partial Transmit Sequence (PTS) using Magic square pattern and adjacent partitioning; and iii) Selective Mapping (SLM) and Tone Reservation (TR) with reduced complexity. These methods are described and algorithms …

Novel Channel Estimation Techniques For Next Generation Mimo-Ofdm Wireless Communication Systems: Design And Performance Analysis, Mohammed Zourob

Electronic Thesis and Dissertation Repository

During the last decade, major evolutions were introduced for Multiple Input Multiple Output (MIMO) wireless communication systems. To reap the full benefits of MIMO systems, the Base Station (BS) and user equipments require accurate Channel State Information (CSI), which can be acquired using one of the two major approaches for Channel Estimation (CE): pilot-based or blind-based CE.

In this thesis, a pilot-based lower complexity channel estimator for Cell-Specific Reference Signals (C-RS) and User Equipment RS (UE-RS) in LTE-A Downlink (DL) system is proposed based on using a hybrid Wiener filter. The proposed system is a sub-optimum scheme that requires 8.8% …

Monostatic Airborne Synthetic Aperture Radar Using Commercial Wimax Transceivers In The License-Exempt Spectrum, Kai Liu

Electronic Thesis and Dissertation Repository

The past half-century witnessed an evolution of synthetic aperture radar (SAR). Boosted by digital signal processing (DSP), a variety of SAR imaging algorithms have been developed, in which the wavenumber domain algorithm is mature for airborne SAR and independent of signal waveforms. Apart from the algorithm development, there is a growing interest in how to acquire the raw data of targets’ echoes before the DSP for SAR imaging in a cost-effective way. For the data acquisition, various studies over the past 15 years have shed light on utilizing the signal generated from the ubiquitous broadband wireless technology – orthogonal frequency …

Physical-Layer Security Enhancement In Wireless Communication Systems, Hao Li

Electronic Thesis and Dissertation Repository

Without any doubt, wireless infrastructures and services have fundamental impacts on every aspect of our lives. Despite of their popularities, wireless communications are vulnerable to various attacks due to the open nature of radio propagation. In fact, communication security in wireless networks is becoming more critical than ever. As a solution, conventional cryptographic techniques are deployed on upper layers of network protocols. Along with direct attacks from lower layer, wireless security challenges come with the rapid evolution of sophisticated decipher techniques. Conventional security mechanisms are not necessarily effective against potential attacks from the open wireless environment anymore. As an alternative, …

Secure Ofdm System Design For Wireless Communications, Hao Li

Electronic Thesis and Dissertation Repository

Wireless communications is widely employed in modern society and plays an increasingly important role in people's daily life. The broadcast nature of radio propagation, however, causes wireless communications particularly vulnerable to malicious attacks, and leads to critical challenges in securing the wireless transmission. Motivated by the insufficiency of traditional approaches to secure wireless communications, physical layer security that is emerging as a complement to the traditional upper-layer security mechanisms is investigated in this dissertation. Five novel techniques toward the physical layer security of wireless communications are proposed. The first two techniques focus on the security risk assessment in wireless networks …