Comparative Analysis between OFDMA and SC-FDMA: Model, Features and Applications

This paper represents Orthogonal Frequency Division Multiple Access (OFDMA) and Single Carrier Frequency Division Multiple Access (SCFDMA) techniques along with the Orthogonal Frequency Division Multiplexing (OFDM). The concept, model, features, scopes, applications and limitation for both types of multiple access have been discussed in this paper. In present 4G and 5G cellular communication system, both OFDMA and SC-FDMA have a notable applications. Dividing the available spectrum into overlapping orthogonal narrowband sub bands, OFDMA ensures high spectral efficiency. Besides by allocating multiple sub carriers to each user, OFDMA provides high data rate, reduces inter blockage interference, minimizes frequency selective fading and so on. But it suffers from high peak to average power ration (PAPR) which results in high power consumption at the transmitter end. SC-FDMA is one of the most promising techniques to solve the PAPR problems. Besides it also removes the capacity problem of wireless cellular systems and provides higher spectral efficiency, depending on multiplexing signals based on their spatial signature. On the other hand, in OFDM due to fixed subcarrier allocations for each user and its performance can suffer from narrowband fading and interference

A novel ultra-low loss rectangle-based porous-core PCF for efficient THz waveguidance: Design and numerical analysis

A novel, rectangle-based, porous-core photonic crystal fiber (PCF) has been modeled for the efficient propagation of a THz wave. The performance of the anticipated model has been assessed using the finite element method (FEM) in the range of 0.5–1.5 THz. Both the fiber core and cladding are modeled with rectangular air holes. Numerical analysis for this model reveals that the model has a lower amount of dispersion of about 0.3251 ps/THz/cm at 1.3 THz. Compared to the other THz waveguides, the model offers an ultra-lower effective material loss of 0.0039 cm−1 at the same frequency. The confinement loss is also lower for this model. Moreover, this model has a high-power fraction of about 64.90% at the core in the x-polarization mode. However, the effective area, birefringence, and numerical aperture have also been evaluated for this model. Maintenance of standard values for all the optical parameters suggests that the proposed PCF can efficiently be applied in multichannel communication and several domains of the THz technology

Ameliorating effects of Raphanus sativus leaves on sodium arsenite-induced perturbation of blood indices in Swiss albino mice

Objective: To evaluate the ameliorating effects of Raphanus sativus leaves (RSL) against sodium arsenite (Sa)-induced adverse effects through mice experiments. Methods: Swiss albino mice were divided into four equal groups: control, Sa, RSL, RSL + Sa. Sa (10 mg/kg body weight/day), and powder form of RSL (50 mg/kg body weight/day) were provided as food supplement orallty. Blood indices were measured using commercially available kits through colorimetric methods. Results: It was observed that lactate dehydrogenase, alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase activities were significantly (P < 0.05) higher in Sa-treated mice than those in the control group. RSL significantly reduced Sa-induced elevation of the activities of these enzymes in serum significantly (P < 0.05). Serum butyrylcholinesterase activity and high density lipoproteins cholesterol levels in Sa-treated mice were significantly (P < 0.05) lower than the control group, and the food supplementation of RSL could significantly (P < 0.05) prevent the reduction of Sa-mediated serum butyryl cholinesterase activity and high density lipoproteins cholesterol levels. RSL could also reduce the Sa-induced elevation of serum urea level significantly (P < 0.05). Conclusions: Results of this study suggest the protective or ameliorating effects of RSL on Sa-induced perturbation of blood indices are related to the hepatic, cardiovascular and kidney dysfunction. Therefore, RSL may be useful to reduce arsenic toxicity in human in the future