Enhanced PAPR in OFDM without Deteriorating BER Performance

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A new portable ELF Schumann resonance receiver: design and detailed analysis of the antenna and the analog front-end

Abstract Schumann resonance oscillation detection is a complex procedure which requires customized and high-quality measurement systems. The primary objective of this work was to design and implement a stand-alone, portable, and low-cost receiver able to measure as much Schumann resonance harmonics as possible. Design, as well as detailed analysis of the efficient induction coil magnetic antenna and the low-noise amplifying-filtering chain, is presented. The detection system includes two coils back to back, resulting in a total coil length of 60 cm. The filtering and amplification chain exhibits an experimentally measured total passband gain equal to 112 dB at 10 Hz and as low as 2.88 nV/√Hz equivalent input noise. In order to validate the new portable ELF Schumann resonance detection and monitoring system, we took measurements at various spots “relatively” free from man-made electromagnetic pollution. Results have shown very clear Schumann resonance peaks for the first six modes with 10-min acquisition time

The Contribution of Society of Social Psychiatry P. Sakellaropoulos to the Psychiatric Reform in Rural Greece

The present paper aims to describe the structure, function, and goals of two of the oldest Mobile Mental Health Units in Greece, namely, the Mobile Mental Health Unit in Fokida (MMHU-F) and the Mobile Mental Health Unit in Thrace (Alexandroupolis, MMHU-T). Information about their historical background, catchment areas, and current staffing, as well as the services provided by each MMHU is discussed. The focus of the paper is slightly biased towards the MMHU-F because it is the only available mental health service in the whole Fokida prefecture. The major goals of the MMHUs are the diagnosis, treatment, and prevention of relapse of severe mental illness within the community. Other important goals of the MMHUs are psychoeducation, psychological support for the family/caregivers, as well as vocational training and support for patients with severe mental illness. Statistical data depicting the demographic characteristics and diagnostic profiles of patients in each MMHU is also provided, and the differences between the two MMHUs are briefly discussed

"Reducing Peak-to-Average Power Ratio of a Turbo Coded OFDM", Wireless Engineering and Technology, vol. 03, no. 04, pp. 195-202, 2012

Orthogonal frequency division multiplexing (OFDM) is vastly used in wireless networks. Its superiority relies on the fact that information can be split in large amount of frequencies. Each frequency is called information subcarrier. OFDM exhibits excellent annotation in channel fades and interferers as only a few subcarriers can be affected and consequently a small part of the original data stream can be lost. Orthogonality between frequencies ensures better spectrum management and obviates the danger of intersymbol interference. However, an essential problem exists. OFDM systems have high peak to average power ratio. This implies large fluctuations in signal power, ending up in increasing complexity of ADCs and DACs. Also, power amplifiers must work in a larger linear dynamic region. In this paper we present two new techniques for reducing Peak to Average Power Ratio (PAPR), that can be added in any OFDM system and we compare them with other existing schemes

Attack Detection for Healthcare Monitoring Systems Using Mechanical Learning in Virtual Private Networks over Optical Transport Layer Architecture

Data security plays a crucial role in healthcare monitoring systems, since critical patient information is transacted over the Internet, especially through wireless devices, wireless routes such as optical wireless channels, or optical transport networks related to optical fibers. Many hospitals are acquiring their own metro dark fiber networks for collaborating with other institutes as a way to maximize their capacity to meet patient needs, as sharing scarce and expensive assets, such as scanners, allows them to optimize their efficiency. The primary goal of this article is to develop of an attack detection model suitable for healthcare monitoring systems that uses internet protocol (IP) virtual private networks (VPNs) over optical transport networks. To this end, this article presents the vulnerabilities in healthcare monitoring system networks, which employ VPNs over optical transport layer architecture. Furthermore, a multilayer network architecture for closer integration of the IP and optical layers is proposed, and an application for detecting DoS attacks is introduced. The proposed application is a lightweight implementation that could be applied and installed into various remote healthcare control devices with limited processing and memory resources. Finally, an analytical and focused approach correlated to attack detection is proposed, which can also serve as a tutorial oriented towards even nonprofessionals for practical and learning purposes

"A Parallel turbo encoder-decoder scheme", In 2nd Pan-Hellenic Conference on Electronics and Telecommunications - PACET΄12

The field of forward error correction was greatly influenced by the discovery of turbo codes. This invention led to a great improvement in terms of Bit-Error-Rate (BER). Various schemes have been proposed and are based either on parallel or serial designs of concatenated decoders. These decoders are iterative using SOVA (soft output viterbi) or MAP (maximum a posteriori) algorithms. They introduce superior recovery functions of data which have been transmitted through noisy environments. Actually, these turbo schemes compared to convolutional codes achieve better data recovery with the increase of the constraint length. Considering all previous principles, we designed a new parallel turbo encoder-decoder system. This system was compared to already existing serial and parallel turbo coding schemes and to a convolutional encoder. Performance level was verified through simulations including Additive White Guassian noise. BER analysis exhibited better results compared to all other designs for various numbers of iterations

"Preliminary BER Study of a TC-OFDM system operating under noisy conditions", In 3rd Pan-Hellenic Conference on Electronics and Telecommunications - PACET΄15

Wireless systems contain transmitters and receivers in order to exchange information. In the past decades, this exchange of information was conducted with the us e of only one modulated carrier (frequency). As wireless technology evolved, new techniques emerged. One of them was unique for its capability of significant lower data loss compared to others. The main concept of the new technique, commonly known as Orthogonal Frequency Division Multiplexing, was the utilization of various orthogonal carriers (frequencies) which were multiplexed with each other in order to prevent system breakdown in the case of frequency fading. In this paper we simulated our enhanced OFDM platform based on Turbo Coding (TC) in the presence of a noisy channel (AWGN, Phase noise, Rician noise, ITU PA3) exhibiting excellent BER performance

"A Parallel turbo encoder-decoder scheme", Poster, In 2nd Pan-Hellenic Conference on Electronics and Telecommunications - PACET΄12, March 16-18, 2012, Thessaloniki, Greece.

The field of forward error correction was greatly influenced by the discovery of turbo codes. This invention led to a great improvement in terms of Bit-Error-Rate (BER). Various schemes have been proposed and are based either on parallel or serial designs of concatenated decoders. These decoders are iterative using SOVA (soft output viterbi) or MAP (maximum a posteriori) algorithms. They introduce superior recovery functions of data which have been transmitted through noisy environments. Actually, these turbo schemes compared to convolutional codes achieve better data recovery with the increase of the constraint length. Considering all previous principles, we designed a new parallel turbo encoder-decoder system. This system was compared to already existing serial and parallel turbo coding schemes and to a convolutional encoder. Performance level was verified through simulations including Additive White Gaussian noise. BER analysis exhibited better results compared to all other designs for various numbers of iterations. <br