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Area Spectral Efficiency of a Macro-Femto Heterogeneous Network for Cell-Edge Users under Shadowing and Fading Effects

M. C. Uko, U. S. Ukommi, S. C. Ekpo, R. Kharel
ACES Journal Paper
Year: 2016      Volume: 31      Number: 9
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The traditional macro-only network is not effective, especially when communication signal is required for users far away from the macrocell base station and located in the cell edge. The signal strength reaching these users is excessively attenuated due to fading and shadowing. The deployment of femtocells around the cell edge of this macrocell helps to reduce the effect of fading and shadowing thereby increasing the overall efficiency of the cellular network. This holds a great promise for adaptive space-based wireless sensor networks, formation-flying satellites and constellations.

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ACES Newsletter Paper
Year: 2006      Volume: 21      Number: 1
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2006 ACES Conference Information

ACES Newsletter Paper
Year: 2006      Volume: 21      Number: 1
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Optimisation of the FGT for Electroheat Multiphysics Modelling

S. Ekpo, A. Sunday, E. Ekpo
ACES Conference Paper
Year: 2009 - Challenges in Scattering, Radiation and Multi-domain Modeling
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Multiphysics modelling of coupled systems is indispensable for accurate, reliable and objective characterization of electroheat phenomena. This paper examines the usefulness of the Fourier series and Green’s function methods for deriving the analytical solutions of such models. An optimized Fourier-Green technique (FGT) is vital for accurate model description and analysis. A numerical solution for a EM-heat flow model was realized for an aluminium metal sample using F90 program code and F95 compiler. A homogeneous time-dependent E-field (μV/m) source, consisting of 500 time steps, was used to study the temperature distribution of the metal sample. The results satisfy the set initial and boundary conditions. Besides, the visualisations show that the temperature profile increases towards the centre, averaging 20oC within the bulk of the sample. The optimized FG function promises to revolutionise biomedical applications of EM-based heating, communications devices, RF and microwave heating and industrial processes amongst others.

GAs with PDSS and Adaptive Parameters for Phased Array Synthesis

A. Sunday, E. Ekpo, S. Ekpo
ACES Conference Paper
Year: 2006 - Phased Arrays
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Genetic algorithms (GAs) are search methods based on the principles and concepts of natural selection and evolution. They are commonly used to solve many optimisation and synthesis problems. An important issue facing the user is the selection of genetic algorithm parameters, such as selection strategy, mutation rate, mutation range, and number of crossovers. This paper demonstrates population decimation selection strategy (PDSS) that ensures proper convergence with adaptive parameters during the optimisation process, which is shown to outperform its best counterpart when used to synthesise phased array weights to satisfy a specified far field sidelobe envelope. When compared to other selection strategies implementations, the algorithm converges faster with the best solutions resulting in a great reduction of computation time.

Parameters Update Integration in EM Analysis of ATL and PTL in the FDM

S. Ekpo, A. Sunday, E. Ekpo
ACES Conference Paper
Year: 2008 - Advanced Transmission Lines Modeling, Macromodeling and Signal Integrity
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The modeling of artificial and planar transmission lines for microwave communications is as critical as the premium set on the bandwidth of the line. Reflectionless networks are ideal for realizing the -3dB signal transmission margin. This paper proposes an electromagnetically (EM)-engineered measurement environment where the parameters of the frequency domain (FD) analysis of the ATL and PTL are adaptively and proactively updated for circuits characterization. This novelty promises immense enhancement in the channel characterization of TEM and dispersive transmission lines.

Modeling MC Effects between Antenna Array-Elements in a Microcellular Environment Using FMM

S. Ekpo, A. Sunday, E. Ekpo
ACES Conference Paper
Year: 2007 - Advanced Computational Techniques in Electromagnetics - 1
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The method of moments (MoM) is often employed for analyzing the induced current on an object in terms of a given basis functions and enforces Maxwell\'s boundary conditions at a finite number of points on the object being modeled. However, one major problem with MoM is the generation of dense matrix and for certain problems, the dimensions of this matrix can be prohibitively large. This can be time-consuming and computationally expensive. We, therefore, propose the fast multipole method (FMM) to accelerate the modeling of the effects of local scattering close to the base station, as well as electromagnetic interactions between the base station array elements. Results [1] unfold its efficiency over alternative approaches vis-à-vis high current-carrying volume elements or number of observation points.

Shadowing Effect on the Area Spectral Efficiency of a Macro-Femto Heterogeneous Network for Cell-Edge Users

M. C. Uko, S. C. Ekpo, U. Ukommi, R. Kharel
ACES Conference Paper
Year: 2015 - S04 Antenna Applications I
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For rural and urban environment, the combined effect of the multiple impairments like multipath fading and shadowing result in faster reduction in the average signal strength as the distance from the single macrocell transmitter increases.

Acoustic Noise Characterization in Dynamic Systems using an Embedded Measurement Platform

B. Adebisi, S. C. Ekpo, A. Sabagh, A. Wells
ACES Conference Paper
Year: 2014 - Microphone Arrays, Sonar Arrays, Directional Radio Antenna Arrays, Radar Arrays and Other Sensor Arrays
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The modelling of an acoustic beamforming in a dynamic system characterized by time-variant state variables requires a reliable knowledge of the noise conditions of the environment and sensor subsystems.

Gain Enhancement of Acoustic Beamforming Arrays in Complex Dynamic Systems

S. C. Ekpo, B. Adebisi, A. Sabagh, A. Wells
ACES Conference Paper
Year: 2014 - Microphone Arrays, Sonar Arrays, Directional Radio Antenna Arrays, Radar Arrays and Other Sensor Arrays
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Acoustic beamforming in complex dynamic systems is a non-trivial task given the time-variant nature of system variables.

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