Widely-Linear processing for faster-than-Nyquist signaling in presence of IQ imbalance
Date
2024-12-13
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Thesis
Degree Level
Masters
Abstract
With the rise in global demands for more connectivity, Faster-than-Nyquist (FTN) signaling is portrayed by many communications engineers and researchers as a promising approach to increase the spectral efficiency (SE) of next-generation wireless communication systems. However, FTN signaling has an inherent problem, which is the introduction of intentional inter-symbol interference (ISI) into communication systems, rendering conventional detection methods worthless. Another challenge is the use of impaired RF devices, which can be available due to their low cost in manufacturing but can experience several impairments, one of which is in-phase and quadrature (IQ) imbalance. In this thesis, we investigate the detection of FTN signaling in the presence of IQ imbalance in frequency-selective fading channels. We show that IQ imbalance at the transmitter and the receiver of FTN signaling results in an image of the transmit and the received signal, respectively, and this image represents additional interference. We use concepts from widely linear processing to exploit the correlation between the received signal and its complex conjugate. In particular, we propose a widely-linear minimum mean square error (WL-MMSE) algorithm to estimate the transmit FTN signaling in the presence of IQ imbalance and frequency-selective channels. We additionally prove that the mean square error (MSE) of the proposed WL-MMSE is smaller than its counterpart of the linear MMSE (L-MMSE). Simulation results verify our findings in terms of bit error rate (BER) and MSE performance.
Description
Keywords
IQ imbalance, Faster-than-Nyquist signaling, Widely-linear, MMSE, Inter-symbol interference
Citation
Degree
Master of Science (M.Sc.)
Department
Electrical and Computer Engineering
Program
Electrical Engineering