Wyniki wyszukiwania - Biblioteka Nauki

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Improvement of Relay Link Capacity in a Multi-hop System by using a Directional Antenna in LTE-A Cellular Network

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Aldhaibani J. A. , Yahya A. , Ahmad R. B.

Przegląd Elektrotechniczny

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2013

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tom R. 89, nr 11

195-201

EN

This paper introduces a new approach for enhancing relay link quality. Two types of antennas were proposed at the relay node (RN). The first type is the directional antenna, which is directed toward the base station to achieve the maximum relay location range and improve the relay link quality, thereby reducing outage probability by increasing relay link capacity. The second type is the omni-directional antenna, which is used for the exchange of information between the RN and attached users. The optimum relay location was derived, thus ensuring the maximum spectral efficiency and best received signal strength over the relay link and cell edge. An improvement of 32% in spectral efficiency and a difference of−62 dBm to −50dBm in received signal strength at the relay link has been observed while considering Interference from neighboring cells. An ATDI simulator, which manages the digital cartography for the first tier of interference in urban areas, verified the numerical results.

PL

Opisano metody poprawy transmisji w sieci komórkowej LTE. Zbadano dwie anteny – antenę kierunkową i wielokierunkową. Antena kierunkowa zapewnia najlepsza jakość transmisji, antena wielokierunkowa jest użyta do wymiany informacji między węzłem a użytkownikiem.

2

Multi-rate transmissions on spectral amplitude coding optical code division multiple access system using random diagonal codes

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Fadhil H. A. , Aljunid S. A. , Ahmad R. B.

Optica Applicata

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2009

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tom Vol. 39, nr 2

225-232

EN

In this paper, we study the use of a new code called random diagonal (RD) code for spectral amplitude coding (SAC) optical code division multiple access (OCDMA) networks, using fiber Bragg-grating (FBG). FBG consists of a fiber segment whose index of reflection varies periodically along its length. RD code is constructed using a code level and data level, one of the important properties of this code is that the cross correlation at the data level is always zero, which means that phase intensity induced phase (PIIN) is reduced. We find the performance of the RD code to be better than those of the modified frequency hopping (MFH) and Hadamard codes. It has been observed from simulation and theoretical results that considering the bit error rate (BER), the RD code performs significantly better than other codes. The ability of RD codes to support simultaneous transmissions at different bit rates is shown through simulated results of the BER and the eye patterns. 10 Gbps and 2.5 Gbps data transmissions have been successfully demonstrated together with FBG decoding scheme for canceling the code level from SAC-signal.

3

Bit error rate (BER) performance of return-to-zero and non-return-to-zero data signals optical code division multiple access (OCDMA) system based on AND detection scheme in fiber-to-the-home (FTTH) networks

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Aldouri M. Y. , Aljunid S. A. , Ahmad R. B. , Fadhil H. A.

Optica Applicata

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2011

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tom Vol. 41, nr 1

173--181

EN

In this paper, we will focus on the modulation format used to create the optical pulses, which are return-to-zero (RZ), and non-return-to-zero (NRZ). Bit error rate (BER) performance is evaluated based on double weight (DW) code. Optical code division multiple access (OCDMA) system is considered a promising technique for fiber-to-the-home (FTTH) access networks. The performance of RZ against NRZ is compared through simulation by using the Optisystem software version 7. We used two networks designed as follows: one used a RZ pulse generator and the second used a NRZ pulse generator, and both systems were tested with and without erbium doped fiber amplifier (EDFA). It has been found that the NRZ pulse generator in this system is better than the RZ pulse generator for all simulation results. The conversion used a Mach-Zehnder interferometer (MZI) wavelength converter. Also, we are proposing a detection scheme known as the AND subtraction detection technique implemented with fiber Bragg grating (FBG) which acts as an encoder and decoder. This FBG is used to encode and decode the spectral amplitude coding DW code in the OCDMA system. The performances are characterized through BER and bit rate (BR), and also the received power at various bit rates.

4

Surface electromyography for assessing triceps brachii muscle activities: a literature review

88%

Ali A. , Sundaraj K. , Ahmad R. B. , Ahamed N. U. , Islam A.

Biocybernetics and Biomedical Engineering

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2013

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tom Vol. 33, no. 4

187--195

EN

The goal of this review was to summarise the scientific findings of research conducted on the triceps brachii muscle using surface electromyography. To achieve this goal, we searched through several articles available from the online databases ScienceDirect and SpringerLink published in the English language between January 2008 and June 2012. We specifically searched for the phrases ‘‘EMG’’ and ‘‘triceps brachii’’ in the title, abstract, keywords or methods sections. From a total of 569 articles we identified 77 potentially relevant studies where 42 studies have been examined triceps brachii muscle activity using surface electromyography that applied in the field of rehabilitation, physiological exercise, sports, and prosthesis control. Among the 42 articles found, 16 studies have been examined triceps brachii muscle activity in rehabilitation, 13 for physiological exercise, 9 for sports, and 4 for prosthesis control in this literature review. We therefore believe that the information contained in this review will greatly assist and guide the progress of studies that use surface electromyography to measure triceps brachii muscle activity in the context of rehabilitation, physiological exercise, sports, and prosthesis control.