In this paper, a proposed model based on phase matrix rotation was suggested to improve the performance of Multicarrier-Code Division Multiple Access (MC-CDMA) lies in Fast Fourier Transform (FFT) algorithm under the Additive White Gaussian Noise (AWGN) and frequency selective fading channel. This model is used to reduce the effect of multipath fading. The results extracted by a computer simulation for a single user, then it compared with the original technique for MC-CDMA based on FFT for both systems. As a result, it can be seen from the proposed technique that a high performance improvement was obtained over the conventional MC-CDMA, where the Bit Error Rate (BER) is widely reduced under different channel characteristics for frequency selective fading and the AWGN channel
WMAN (wireless metropolitan area network) technology is based on the IEEE 802.16 air interface standard suite, which provides the wireless technology for fixed and nomadic data access. WMAN employs orthogonal frequency division multiplexing (OFDM), and supports adaptive modulation and coding depending on the channel conditions. The objective of this paper is to study the performance of the IEEE 802.16d WMAN physical layer under Nakagami model as a Multi-path and frequency-selective fading channel beside the additive white Gaussian noise (AWGN) and Doppler. Finally, we compared it with the Rayleigh fading model. The transmission bit rate, Probability of Error ( ) and estimated SNR have been compared under single/multi path propagation conditions.
Better understanding the innovative process of renewable energy technologies is important for tackling climate change. Concentrated solar power (CSP) is a method of electric generation fueled by the heat of the sun, an endless source of clean, free energy. Commercially viable and quickly expanding, this type of solar technology requires strong, direct solar radiation and is primarily used as a large, centralized source of power for utilities. This study has focused on the feasibility of improving concentrating solar power (CSP) plant efficiency, by manufacturing a diminished prototype. Three states were studied, coloring the central target with a selective black color, fixing a reflector with arc form behind the target, and using these two changes together. The results showed an improvement in the thermal storage varied form month to month. The maximum stored energy was gained at August with increments about 56.1%, 58.63%, 62.23 and 64.69% for ordinary target, black painting, using reflector alone and black target with reflector together, respectively compared with stored energy for March.
This research presented a strategy for designing a particular set of surfaces, obtained by the technique of cross-sectional design. The surfaces considered were formed by sliding a Bezier curve (profile curve), and also this research describes an automatic procedure for selective identification of sampling points in reverse engineering applications using Coordinate Measurement Machine. In addition, Matlab program have been used in the present work so as to plot the curve sections of the surfaces using transformation matrices. UGS program have been also used to connect the sections that designed in Matlab program to get the final shape of the proposed surface. It can be concluded that the whole steps task which built in the present research can be programmed in a single block of the part program that’s from it can be create any curve or surface at minimum designing time.