Ultra-wideband (UWB) radio is the transmission of data using an extremely wide bandwidth and very low power spectral density. In this thesis, the mereits and challenges of UWB architectures versus conventional narrowband architectures will be compared. Pulsed UWB systems can be implemented with very simple architectures. These advantages make UWB...
Circuits operating outside the earth’s atmosphere are more vulnerable to cosmic radiation and require special design consideration. The purpose of this work is to explore methods of mitigating the effect of radiation in phase locked loop (PLL) circuits. Several voltage controlled oscillators (VCOs) and two complete PLLs are designed and...
With an increasing number of wireless applications at microwave frequencies, the frequency spectrum is becoming quite crowded. Due to this congestion, the current state of technology is leading towards upper microwave and millimeter wave spectra as they also offer other distinct advantages such as larger bandwidth and smaller component footprint....
Time of Arrival (TOA) is a popular technique used for geolocation. This thesis evaluates the use of TOA techniques indoors. The accuracy of measuring distances using TOA is dependent on the bandwidth of the system and the multipath conditions between the receiver and transmitter. System bandwidth has a significant effect...
The continued scaling of deep-submicron CMOS technology enables low-voltage high-frequency phase-locked loops (PLLs) to be fully integrated in complex mixed-signal systems. However, fluctuations due to the manufacturing process and variations in
environmental conditions, such as supply voltage and temperature, are also significantly increased. As a result, the performance of PLLs...
This thesis proposes a novel fully digital technique for the estimation and correction of the DAC error in multi-bit delta sigma ADCs. The structure of the DAC error is indicated through a simple model for unit-element based DACs. The impact of the DAC error on the performance of ADC is...
In this thesis, maximum likelihood Doppler frequency estimation and phase noise suppression algorithms for Orthogonal Frequency Division Multiplexing (OFDM) systems are presented. A novel handover decision algorithm for wireless systems, called predictive base station switching (PBSS), is also introduced.
The maximum Doppler Frequency is the ratio of the speed of...
Delta-Sigma (ΔΣ) analog-to-digital converters (ADCs) are widely used in wireless transceivers. Recently, continuous-time (CT) ΔΣ ADCs gain growing interest in wireless applications for their lower power consumption and wider input bandwidth as compared with the discrete-time (DT) counterparts.
In this thesis, a wideband low-power CT ΔΣ modulator for next generation...
Orthogonal frequency division multiplexing (OFDM), which has been very attractive for future high rate wireless communications, is very robust to channel multipath fading effect while providing high transmission data rate with high spectral efficiency.
Multiple antennas can be combined with OFDM to increase diversity gain and to improve spectral efficiency...
Authentication protocols play important roles in network security. A variety of authentication protocols ranging from complex public-key cryptosystems to simple password-based authentication schemes have been proposed. However, currently there is no fully secure authentication scheme that can resist all known attacks. When a user authentication is performed over an insecure...