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Menoufia Journal of Electronic Engineering Research
1687-1189
1687-1189
2008
17
2
Ultimate Optical Soliton Transmission with Dispersion Management in Ultra-Wide Wavelength Division Multiplexing (UW-WDM) Systems
Hossam A.
Hussein
Osama A.
Oraby
Abd El-Naser A.
Mohammed
Amina E.
Mohammed
In the present paper, we have investigated the ultimate optical soliton transmission bit rate of 4800 channels with chromatic dispersion management in ultra-wide wavelength division multiplexing (UW-WDM) systems. Thermal effects are taken into account. Four effects are investigated, namely the soliton bit rate of the segment of negative chromatic dispersion, soliton bit rate of the segment of positive chromatic dispersion, soliton bit rate at the average controlling set of parameters, and finally, the average dispersion of the two segments as successive cells. The investigation is processed taking into account thermal, spectral, and static pressure dependences.Binary glass made of germania-doped-silica single-mode optical fiber is considered [SiOR 2R(1-x)+GeOR 2R(x)]. The nonlinear refractive index is considered as a function of the germania mole fraction (x). The management of total chromatic dispersion is done using two successive segments of fibers of equal or of different lengths and alternating ( positive-negative ) total chromatic dispersions. It is found that the transmitted soliton bit rate undergoes severe reduction due to the thermal variations. Also, the dispersion management possesses remarkable effects on that bit rates.
2008
07
01
79
94
Menoufia Journal of Electronic Engineering Research
1687-1189
1687-1189
2008
17
2
Net Effective Gain of Multi-Pumping Raman Amplifier in Ultra-Wavelength Division Multiplexing and Ultra-Long-Haul Optical Communication System
Abd El-Naser A.
Mohammed
In the present paper, a net effective gain of multi-pumping Raman amplifier in ultra-wavelength division multiplexing (UW-WDM) and ultra long-haul (ULH) optical communication systems has been modeled and parametrically investigated over wide ranges of affecting parameters, taking into account the polarization effect. NR pumps are processed with or without equal spectral spacing. The effective fiber core area, the gain coefficients and the amplified spontaneous emission power ASE (as a measure of the minimum detectable power) are calculated over the operating wavelength. The above three quantities are cast in simple polynomial forms. The average net Raman gain, the on-off Raman gain, the signal-to-noise ratio at the effective length has been investigated also. The obtained results are employed to find the average repeater spacing over the spectral range under the processing. It is concluded that for repeater spacing, the total injected Raman powers are the vital factor rather than the number of amplifiers, while for the gain spectral width, the number of amplifiers is the vital factor. The central wavelength of the subset of channels that propagates in a link indicates the order of link. The total number of links in the core determines the ultimate values of different effects.
Multi-Pumping Raman Amplifiers
Ultra-Long Haul Optical Communication Systems
Ultra-Wide Wavelength Division Multiplexing
2008
07
01
95
113
Menoufia Journal of Electronic Engineering Research
1687-1189
1687-1189
2008
17
2
Rapid Estimation for Spreading Functions of Multipath CDMA Wireless Communication Channels
ABDULLAH ALI
ALSHEHRI
In this paper, we present a robust and fast computational algorithm for estimating the spreading function of multipath CDMA wireless communication channels in multi-user Direct Sequence Spread Spectrum (DSSS) communication systems. Transmission channels spread the message signals in time and frequency and are typically modeled as random, time-varying systems. The proposed algorithm is to provide a time-frequency dependent windows that can be computed priori to estimate the spreading function of multipath wireless communications channels. Computing such windows priori at the receiver will reduce a significant amount of computational load and to improve the previous proposed channel estimation work. It is shown that the estimation of the parameters of such models is possible by means of the spreading function which is obtained from the discrete time-frequency evolutionary kernel of the received signal using the discrete evolutionary transformation DET.
Spreading function
Spread spectrum communications
Multipath channel modeling and estimation
Evolutionary time-frequency analysis
2008
07
01
115
124
Menoufia Journal of Electronic Engineering Research
1687-1189
1687-1189
2008
17
2
Design of a Fuzzy-Based PID Controller for a DC Servomotor Position Control
Mosleh
Al-Harthi
In this paper, a fuzzy controller is designed for a DC servomotor position control using Adaptive Neuro-Fuzzy Inference System (ANFIS). The proposed design procedure is divided into 2 steps. In the first, for a wide range of parameter change, a Proportional-Integral-Derivative (PID) controller is designed to control the DC servomotor for regulation and tracking problems. In the second, the error, between the desired and actual motor position, its derivative and its integral, and the PID output are used as training data to train iteratively a fuzzy inference system using ANFIS. The effectiveness is demonstrated through diverse tests, namely, parameter variation, regulation, and tracking of the desired shaft position.
DC Servomotor
Adaptive Neuro-Fuzzy Logic
Proportional – Integral - Derivative Controller
2008
07
01
125
138
Menoufia Journal of Electronic Engineering Research
1687-1189
1687-1189
2008
17
2
Different mac protocols for next generation wireless atm networks
Sami A.
El-Dolil
This paper presents a comparison between three proposed Medium Access Control (MAC) Protocols for next generation multimedia wireless ATM (WATM) networks. To support the ATM CBR, VBR, ABR services to end users, a MAC protocol must be able to provide bandwidth on demand with suitable performance guarantee. The protocols have been proposed to efficiently integrate multiple ATM traffics over the wireless channel while achieving high channel utilization. The objective of the comparison is to highlight the merits and demerits of the three proposed protocols
2008
07
01
139
158
Menoufia Journal of Electronic Engineering Research
1687-1189
1687-1189
2008
17
2
FDTD Analysis of A New Wideband Inserted RDRA
A. S.
Elkorany
, S. M.
Elhalafawy
H. A.
Sharshar
The present paper is devoted to the enhancement of the impedance bandwidth of a coaxial probe fed rectangular dielectric resonator antenna (RDRA) by introducing an air gap between the rectangular dielectric resonator (RDR) and the ground plane. An impedance bandwidth of approximately 31% is obtained when the coaxial probe only touches the bottom surface of the RDR. Good agreement between finite difference time domain (FDTD) and high frequency structure simulator (HFSS) results is obtained.
probe feed RDRA
wideband
air gap inserted
FDTD
HFSS
2008
07
01
159
166
Menoufia Journal of Electronic Engineering Research
1687-1189
1687-1189
2008
17
2
Capacity Estimation of IEEE 802.11e WLAN
Nawal A.
El-fishawy
M.M.
Zahra
Mostafa
El-gamala
Today’s IEEE 802.11 WLAN is an excellent solution for the broadband wireless networking. However, it lacks the capability to support real time services such as voice and video. IEEE 802.11e is an upcoming QoS enhanced standard supported by the IEEE working group. IEEE 802.11e protocol provides a level of service differentiation by statically associating different QoS parameters for pre-defined traffic classes. This paper describes the new QoS features of 802.11e protocol. The performance of 802.11e will be investigated and compared with legacy protocol through computer simulation. Additionally, the 802.11e WLAN capacity will be presented in different scenarios.
2008
07
01
167
183
Menoufia Journal of Electronic Engineering Research
1687-1189
1687-1189
2008
17
2
A Survey of Multicast Routing Protocols for Ad-Hoc Wireless Networks
Moukhtar A.
Ali
Ayman
EL-SAYED
Ibrahim Z.
MORSI
Many network applications require transmitting the same single copy of data packets concurrently to many destinations, it is called multicasting. Wired and infrastructure-based wireless networks are supported by many multicast routing protocols. But, applying this concept in Mobile Ad hoc wireless NETworks (MANETs) is a big challenge. Ad hoc wireless networks composed of self-organized mobile nodes that can move arbitrarily without any preexisting communication infrastructure base stations. It causes producing dynamic and unpredictable network topology. Many proposals are introduced trying to solve multicast supporting problem in MANETs. In this paper, multicast routing protocols in MANETs that was proposed in recent years will be classified according to different view points such as multicast topology, topology initialization, topology maintenance, core or coreless approach, and dependency on unicast routing protocols.
Multicast
Ad Hoc Wireless Networks (MANETs)
2008
07
01
185
198
Menoufia Journal of Electronic Engineering Research
1687-1189
1687-1189
2008
17
2
New Architecture of Interconnect for High-Speed Optical Computerized Data Networks (Nonlinear Response)
Hamdy. A.
Kelash
Ashraf. M.
Abou-Tabl
In the present paper, architecture of optical interconnect is built up on the bases of four Vertical-Cavity Surface-Emitting Laser Diodes(VCSELD) and two optical links where thermal effects of both diodes and links are included. Nonlinear relations are correlated to investigate the power-current and the voltage-current dependences. The good performance (high speed) of the interconnect is deeply and parametrically investigated under wide ranges of the affecting parameters. The high speed performance is processed through three different effects, namely the device 3-dB bandwidth, the link dispersion characteristics, and the transmitted bit rate (soliton). Eight combinations are investigated, each possesses its own characteristics. The best architecture is the one composed of a VCSELD that operates at 850 nm and the silica fiber whatever the operating set of causes. This combination possesses the largest device 3-dB bandwidth, the largest link bandwidth and the largest soliton transmitted bit rate. The increase of the ambient temperature reduces the high-speed performance of the interconnect.
2008
07
01
199
216