A New Reduced-Complexity Detection Scheme for Zero-Padded OFDM Transmissions

Recently, zero-padding orthogonal frequency division multiplexing (ZP-OFDM) has been proposed as an alternative solution to the traditional cyclic prefix (CP)-OFDM, to ensure symbol recovery regardless of channels nulls. Various ZP-OFDM receivers have been proposed in the literature, trading off performance with complexity. In this paper, we propose a novel low-complexity (LC) receiver for ZP-OFDM transmissions and derive an upper bound on the bit error rate (BER) performance of the LC-ZP-OFDM receiver. We further demonstrate that the LC-ZP-OFDM receiver brings a significant complexity reduction in the receiver design, while outperforming conventional minimum mean-square error (MMSE)-ZP-OFDM, supported by simulation results. A modified (M)-ZP-OFDM receiver, which requires the channel state information (CSI) knowledge at the transmitter side, is presented. We show that the M-ZP-OFDM receiver outperforms the conventional MMSE-ZP-OFDM when either perfect or partial CSI (i.e., limited CSI) is available at the transmitter side.Index Terms-Zero-padding, orthogonal frequency division multiplexing (OFDM), equalization

Analysis and Design of Diversity Techniques for Terrestrial and Underwater Acoustic Communications

Since the early 1880’s, wireless broadband communications have been growing at explosive rates. While the personal communication systems have almost exhausted the spectrum, higher and higher data rates are required to support the ever demanding wireless services. Recently, to improve the spectral efficiency, diversity gains, and interference and power management for wireless multimedia and internet services, by combining the signals at both ends and effectively creating multiple parallel spatial data pipes, the multiple-input multiple-output (MIMO) technology has become a convenient framework. Motivated by these practical concerns, this thesis addresses the analysis and design of diversity techniques for terrestrial and underwater acoustic communication channels, in two parts. Part I studies novel relay selection strategies and diversity techniques for single carrier frequency domain equalization (SC-FDE) multi-relay cooperative networks, considering maximum-likelihood (ML) and minimum mean-square error (MMSE) receivers. We further extend our analysis to two-way relaying (TWR) networks, while incorporating different power control techniques. Building on our results on the diversity and error performance of the single relay and TWR cooperative systems, we extend our analysis to design of MMSE-based optimum beamforming matrices at user and relay terminals in a multi-user, multi-antenna TWR cooperative system. We further present a joint user-relay antenna selection algorithm by applying the estimation of distribution algorithm (EDA). The final contribution of the first part of this thesis is to extend our analysis to large relay networks and address the prohibitive computational and implementation complexity cost of the exhaustive search algorithms for joint transceiver/relay beamforming matrix design in large amplify-and-forward (AF) MIMO TWR networks, while incorporating the orthogonal matching pursuit (OMP) algorithm. The second part of this thesis focuses on the performance of differentially encoded space-time and space-frequency block coding techniques for terrestrial and underwater communication channels

Equalization techniques for broadband wireless networks

Wireless sensor networks (WSNs) are characterized by low-power devices equipped with communication capabilities. Due to the lack of a set infrastructure, WSNs exhibit characteristics fundamentally different from traditional networks. The existing literature in conventional wireless networks, therefore, cannot be applied to WSN design. The recently introduced Cooperative diversity techniques exploit the broadcast nature of wireless transmission, creating a virtual antenna array through cooperating nodes. This form of diversity is therefore well suited for WSNs. The research in this field is however, still in it\u27s infancy. Particularly, most of the current literature in this area assumes an idealized transmission environment with an underlying frequency-flat fading channel model and perfect channel state information, which are far away from being realistic if wideband sensor applications or mobile sensor networks are considered. Motivated by these practical concerns, this thesis addresses the analysis and design of efficient equalization techniques for non-cooperative and cooperative wireless networks

A new reduced-complexity detection scheme for zero-padded OFDM transmissions

Abstract Recently, zero-padding orthogonal frequency division multiplexing (ZP-OFDM) has been proposed as an alternative solution to the traditional cyclic prefix (CP)-OFDM, to ensure symbol recovery regardless of channels nulls. Various ZP-OFDM receivers have been proposed in the literature, trading off performance with complexity. In this paper, we propose a novel low-complexity (LC) receiver for ZP-OFDM transmissions and derive an upper bound on the bit error rate (BER) performance of the LC-ZP-OFDM receiver. We further demonstrate that the LC-ZP-OFDM receiver brings a significant complexity reduction in the receiver design, while outperforming conventional minimum mean-square error (MMSE)-ZP-OFDM, supported by simulation results. A modified (M)-ZP-OFDM receiver, which requires the channel state information (CSI) knowledge at the transmitter side, is presented. We show that the M-ZP-OFDM receiver outperforms the conventional MMSE-ZP-OFDM when either perfect or partial CSI (i.e., limited CSI) is available at the transmitter side. Index Terms-Zero-padding, orthogonal frequency division multiplexing (OFDM), equalization.</p

Yoga Effects on Anthropometric Indices and Polycystic Ovary Syndrome Symptoms in Women Undergoing Infertility Treatment: A Randomized Controlled Clinical Trial

The aim of this study was to investigate the effects of yoga exercises on anthropometric parameter and clinical sign of PCOS among women undergoing infertility treatment. This clinical trial study was performed on 61 women with PCOS who have undergone infertility treatment at Sarem Hospital in Tehran, Iran. The patients were first selecting based on purposeful and then randomly assigning to the intervention and control groups. In the intervention group, yoga exercises were performed for 6 weeks and the patients in the control group only received routine care. Anthropometric parameters and clinical signs were performed and recorded. After the intervention, here was a significant reduction in hirsutism, abdominal circumference, and hip circumference scores in the intervention group compared to the control group (P<0.05). Given the effects of yoga exercises on the improvement of hirsutism, abdominal circumference, and hip circumference, it is suggested to use yoga as a treatment strategy in women with PCOS