Design and Performance of SEFDM Signals with Power Allocation

This work presents preliminary investigations into the use of power allocation for the multi-carrier non-orthogonal spectrally efficient frequency division multiplexing (SEFDM) signalling format. SEFDM is utilized to improve the spectral efficiency compared to conventional orthogonal frequency division multiplexing (OFDM), by violating the orthogonality condition and getting the sub-carriers closer to each other. In this paper, subcarriers within the same SEFDM symbol are allocated different power levels. Results show that such power allocation is beneficial to SEFDM from several perspectives: i) Overall system stability enhancement; ii) a drastic complexity reduction in SEFDM detector; iii) peak to average power ratio (PAPR) performance improvement

Design and Implementation of Portable Sensory System for Air Pollution Monitoring

Air pollution is becoming an increasingly serious issue, leading to many environmental problems such as the fog-haze weather phenomenon, which can cause great harm to human health. This paper focuses on the design and fabrication of a portable sensory system for air pollution monitoring, which can detect the temperature, humidity and particulate matter (PM). This will be used as a tool to help reduce the harm of air pollution on people. This sensor mainly consists of a microprogrammed control unit, a temperature & humidity sensor DHT11, a dust sensor GP2Y1010AU0F, LCD, keys and, LEDs. Ambient dust concentrations, temperature and humidity values will be displayed on the LCD. The corresponding light alert signals and sound alert signals are sent when the measured values are beyond their safe ranges

Power management using photovoltaic cells for implantable devices

This paper presents a novel inductor-less switched capacitor (SC) DC-DC converter, which generates simultaneous dual-output voltages for implantable electronic devices. Present dual output converters are limited to fixed ratio gain, which degrade conversion efficiency when the input voltage changes. The proposed power converter offers both step-up and step-down conversion with 4-phase reconfigurable logic. With an input voltage of 1 V provided by photovoltaic (PV) cells, the proposed converter achieves step-up, step-down and synchronised voltage conversions in four gain modes. These are 1.5 V and 0.5 V for Normal mode, 2 V and 1 V for High mode, 2 V for Double Boost mode, as well as 3 V and 2 V for Super Boost mode with the ripple variation of 14-59 mV. The converter circuit has been simulated in standard 0.18 μm CMOS technology and the results agree with state-of-the-art SC converters. However, our proposed monolithically integrated PV powered circuit achieves a conversion efficiency of 85.26% and provides extra flexibility in terms of gain, which is advantageous for future implantable applications that have a range of inputs. This research is therefore an important step in achieving truly autonomous implantable electronic devices

The role of transcranial grayscale and Doppler ultrasound examination in diagnosis of neonatal hypoxic-ischemic encephalopathy

Background: The role of transcranial grayscale ultrasound (TC-GSUS) and transcranial color Doppler (TCD) in the diagnosis and prognosis of neonatal hypoxic-ischemic encephalopathy (HIE) is still questionable.Objective: This study targeted to evaluate the role of TC-GSUS and TCD in diagnosis and prediction of the outcome of neonates with suspected HIE in comparison to Sarnat's clinical scoring.Patients and methods: 26 neonates with suspected HIE were clinically evaluated and the severity of HIE was categorized according to Sarnat's clinical staging. Then, all neonates underwent sonographic examinations. TC-GSUS was performed at levels of anterior, mastoid, and posterior fontanelles and the level of the temporal window.Results: Cranial biometry had negative and positive rates for HIE of 7.7% and 92.3%, respectively. Using TC-GSUS, periventricular leukomalacia, intraventricular hemorrhage, brain edema, and hydrocephalus were detected in 17, 19, 14, and 16 patients, respectively. According to the resistive index (RI) of intracranial vessels, TCD excluded HIE in 11 patients and assured diagnosis of HIE with varying severity in 15 patients. Five neonates died and four developed neurological affection during follow-up. The outcome was correlated with Sarnat’s scoring, ventricular-hemispheric ratio, and abnormalities of RI. Statistical analyses defined severity of HIE as judged by RI as the significant predictor for mortality and abnormal RI of anterior cerebral (ACA) and internal carotid arteries (ICA) are the most significant predictors of outcomes.Conclusion: TCD can diagnose HIE in neonates with high sensitivity and specificity and abnormal RI of ICA and ACA might be used as valuable diagnostic and prognostic tests

Power Allocation for Detection Performance Enhancement of SEFDM Signals

Spectrally efficient frequency division multiplexing (SEFDM) is a multi-carrier signalling format, which has a higher spectral efficiency than conventional orthogonal frequency division multiplexing (OFDM) signals. This work presents preliminary investigations into the use of power allocation for SEFDM. In this method, different subcarriers within the same SEFDM symbol are allocated different power levels. Results show that such power allocation is beneficial to SEFDM detection, with a particular case studied here of the suboptimal fixed sphere decoder (FSD) detector. The investigated method results in a drastic complexity reduction compared to FSD without power allocation for the same error performance

Signal coding and interference cancellation of spectrally efficient FDM systems for 5G cellular networks

This paper explores new multicarrier signals and systems for 5G; spectrally efficient frequency division multiplexing (SEFDM), in which higher spectral efficiency (SE) compared to conventional orthogonal frequency division multiplexing (OFDM) is achieved by violating the orthogonality of its subcarriers. This work proposes new system and receiver models and then investigates the employment of various forward error correction (FEC) techniques, as well as a new interference cancellation receiver architecture to improve the overall system performance by ameliorating the effects of inter-carrier interference (ICI). Results show that the use of coded SEFDM system can drastically increase the SE by up to 67% relative to OFDM, at the expense of a power penalty below 3dB

SEFDM: Spectral Efficiency Upper Bound and Interference Distribution

This work explores the statistical model for a 5G and beyond (5GB) multi-carrier signal candidate; spectrally efficient frequency division multiplexing (SEFDM), in which the orthogonality between its subcarriers is intentionally violated compared to conventional orthogonal frequency division multiplexing (OFDM). A mathematical model describing the statistical characteristics of inter-carrier interference (ICI) is derived and verified through system model simulations. Results show that the ICI is of normal distribution, whose variance is dependent on both the level of bandwidth compression and on the signal level. Models developed are used to derive the error bounds of SEFDM signals in Gaussian noise channels, as well as the upper bound of SEFDM spectral efficienc

Robust Channel Estimation Methods for Spectrally Efficient FDM Systems

This paper proposes and explores a novel channel estimation scheme for non-orthogonal multi-carrier signals and systems; spectrally efficient frequency division multiplexing (SEFDM), in which higher spectral efficiency is achieved by violating the orthogonality of its subcarriers. The proposed scheme is distinguished by its simplicity, low computational complexity, high accuracy and performance independent of the number of subcarriers and compression factor. The presented results demonstrate the efficacy of the proposed scheme by comparing its complexity and performance to other estimation schemes

Simulation of Photovoltaic Cells for Implantable Sensory Applications

Wireless biomedical implantable devices provide a variety of applications based on identification, health, and safety of mankind. Power harvesting and power generation methods through human tissues are still looming challenges because of low efficiency and energy instability. The minimum tissue loss at the optical transparency windows of 650 nm-1350 nm. Photovoltaic cells can be effectively used to provide the necessary power for these implantable devices. However, there have been no previous investigations into the optimum dimensions nor properties of these solar cells. In this case, we show an accurate multi-physics simulation of the performance of photovoltaic cells for implantable devices under the skin. A combination of semiconductor and optical simulations are developed in order to analyse the electro-optic behaviour of these cells. In addition, the efficiencies of 8.97 % and 0.26 % were evaluated under air and air-skin multilayer respectively

Chemical compositions and heavy metal contents of Oreochromis niloticus from the main irrigated canals (rayahs) of Nile Delta

AbstractThe present study aimed to assess the seasonal variations of the proximate chemical composition, physicochemical, microbiological aspects and heavy metal concentrations of Oreochromis niloticus muscles collected from The Nile rayahs from spring 2014 to winter 2015. Rayahs are the main irrigated canals of Nile Delta, Egypt and represent El Tawfiki, El Menoufy, El Behery, and El Nasery rayahs. Results showed a spatial and temporal significant difference (p<0.01) in the proximate composition and Physicochemical aspects of O. niloticus muscles. The moisture, protein, fat, ash, carbohydrates and calorific values varied between (78.55–80.77%), (16.10–17.88%), (1.10–1.95%), (0.55–1.50%), (0.10–0.94%) and (78.37–89.73%), respectively. Heavy metal accumulation in the O. niloticus muscles showed irregular distributions with descending order of: Fe>Zn>Mn>Cu>Pb>Cd. Generally, heavy metals, TVB-N, TMA, TBA and TVC did not exceed the maximum permissible limits in the tissues of O. niloticus. The values of Hazard Index (HI) and Hazard Quotient (HQ) are lower than the acceptable limits, which indicate that the metals in O. niloticus in the Nile rayahs, Egypt, do not pose any particular human health risk concern. Therefore, O. niloticus muscles collected from four rayahs are safe for human consumption and could be used as a source of healthy diet for humans