COSMAS K E M D I R I M AGUBOR (original) (raw)

Papers by COSMAS K E M D I R I M AGUBOR

Radio electronics and communications systems, 2022

Path Loss (PL) is a factor that contributes to signal impairment in a wireless channel and can be... more Path Loss (PL) is a factor that contributes to signal impairment in a wireless channel and can be predicted using empirical models such as Okumura-Hata, Egli, COST, and ECC-33. These models are known to be inaccurate when used in areas different from where they are meant for. In this paper an empirical model suitable for PL prediction in 4G Long Term Evolution (LTE) network was modified and optimized. Measured PL values were obtained and compared with the existing models in order to obtain the closest model to the measured data. The Okumura-Hata model as the closest to the measured values was modified using the loss exponent obtained for FUTO terrain and optimized for better performance using the developed autoregressive (AR) model. The measured data, the existing, modified and optimized AR [opt(AR m)] models were simulated using the MATLAB software. The performances of the existing and opt(AR m) models were evaluated using the root mean square error (RMSE). The results obtained show that the proposed opt(AR m) model is the best as compared to the existing models due to its lowest RMSE value, and thus it can be used to estimate PL for mobile radio signal in FUTO

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Radioelectronics and Communications Systems, 2022

Path Loss (PL) is a factor that contributes to signal impairment in a wireless channel and can be... more Path Loss (PL) is a factor that contributes to signal impairment in a wireless channel and can be predicted using empirical models such as Okumura-Hata, Egli, COST, and ECC-33. These models are known to be inaccurate when used in areas different from where they are meant for. In this paper an empirical model suitable for PL prediction in 4G Long Term Evolution (LTE) network was modified and optimized. Measured PL values were obtained and compared with the existing models in order to obtain the closest model to the measured data. The Okumura-Hata model as the closest to the measured values was modified using the loss exponent obtained for FUTO terrain and optimized for better performance using the developed autoregressive (AR) model. The measured data, the existing, modified and optimized AR [opt(AR m)] models were simulated using the MATLAB software. The performances of the existing and opt(AR m) models were evaluated using the root mean square error (RMSE). The results obtained show that the proposed opt(AR m) model is the best as compared to the existing models due to its lowest RMSE value, and thus it can be used to estimate PL for mobile radio signal in FUTO

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International Journal of Wireless and Microwave Technologies, 2022

5G Heterogeneous network is characterized with small cells in close proximity with one another wh... more 5G Heterogeneous network is characterized with small cells in close proximity with one another which in most cases are active even at low traffic load periods. Such scenarios lead to unnecessary large energy consumption and co-frequency interference. This large energy consumption and interference in 5G heterogeneous networks have been an issue widely discussed in several technical literature. Different and attractive techniques on energy management have been investigated and proposed. All these have been in seeking ways of minimizing or reducing energy consumption in mobile networks. In this study the on/off and sleep-mode schemes as energy management techniques have been reviewed with the major aim of identifying weak areas of both techniques and suggesting ways which will be useful for further research works in the future. In doing so recent literature on the subject matter were consulted. The on/off and sleep-mode schemes involve switching processes which result to loss of data and information during change of state. Quality of service issues arising from incomplete or proper switching process and unnecessary delay perceived by the users were observed as major concern for both schemes. For further work, amongst other suggestions, it is suggested that the time needed between system switching command and switching operations be considered as an important factor in eliminating switching problems which will positively affect the overall quality of service.

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International Journal of Wireless and Microwave Technologies, 2021

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International Journal of Wireless & Mobile Networks, 2021

This study was carried out to investigate the spectrum utilization of the licensed Radio Frequenc... more This study was carried out to investigate the spectrum utilization of the licensed Radio Frequency (RF) spectrum in Rumuokwuta, Port Harcourt. An outdoor measurement of spectrum occupancy was carried out in a high-rise building situated at Rumuokwuta urban area in Port Harcourt, Nigeria using RF explorer spectrum analyzer and a personal computer laptop system. Spectrum activities in the band of 240-960 MHz were monitored for 24 hours. The frequency band was subdivided into 24 sub bands each with a span size of 30 MHz. Scanning of bands was made efficient using a python script that scans a range, analyzed the frequencies and signal strengths for 112 data points, saves data in CSV file format, scans the next range until the 24 ranges were scanned. The process was repeated to achieve 15 iterations. With a noise floor of - 110dBm, a threshold of -95dBm was used to determine the presence of signal, hence the spectrum occupancy of measured bands. Results showed that out of the 24 investig...

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The performance of a CDMA1xEV-DO wireless network operating at a frequency of 876.76MHz in the ci... more The performance of a CDMA1xEV-DO wireless network operating at a frequency of 876.76MHz in the city of Port Harcourt, Nigeria was evaluated in his work. Several network performance challenges ranging from poor network coverage to overall quality of service degradation have been recently experienced by the network users. These obvious challenges attributed to finding the efficient method for the system upgrade. Field measurements were conducted in some selected urban areas in Port Harcourt such as Aba road, Ikwerre road and Liozu roadusing Agilent tool E6474 and ZTE 302 test phone at vehicular speed. The received signal strength (RSS) was gathered from the transceiver stations of Visafone with transmitting power of 27W, mounted on a steel tower with average height of 40m and mobile height of 1.5m.The measurements were conducted within the range of 100 to 1200 meters at an interval of 100m apart. The computed pathloss exponent and the standard deviation were obtained as 3.24 and 5.11d...

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European Journal of Engineering Research and Science, 2020

This paper focuses on the Performance Improvement of a Direction Finding System Antenna Using M... more This paper focuses on the Performance
Improvement of a Direction Finding System Antenna Using
Method of Moment (MoM) Approach. The work is developed
to provide an approximate current distribution for a direction
finding system antenna by employing the use of Method of
Moment on an array of Yagi-uda antenna. The parameters of
the experimental antenna are derived and analyzed via
Magnetic Vector Potential (MVP) operator. The accurate
current flowing through the radiating elements of the direction
finding system is analyzed using combination of Method of
Moment technique and Magnetic Vector Potential (MVP)
operator. This helps to avoid the detection of false alarms and
inability of the system to detect remote targets. A typical
direction finding system Yagi antenna is designed and operated
at a frequency range of 0.6- 0.8 GHz. The antenna has a single
reflector, an active (driven) element and three (3) parasitic
directors. The antenna parameters are simulated using
MatLab R2010a software tool. The average pointing vector of
the designed Yagi antenna was obtained as 3.73watt per square
metre, and Radiation Intensity value of about 9.400 coulomb
per kilogram. The simulation results indicate an appreciable
increase in directivity of 9.03dBi, an enhanced directive gain
compared to that of the equivalent dipole antenna of 1.76dBi,
signifying 7.27dBi enhancement.

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Radioelectronics and Communications Systems, 2022

Path Loss (PL) is a factor that contributes to signal impairment in a wireless channel and can be... more Path Loss (PL) is a factor that contributes to signal impairment in a wireless channel and can be predicted using empirical models such as Okumura-Hata, Egli, COST, and ECC-33. These models are known to be inaccurate when used in areas different from where they are meant for. In this paper an empirical model suitable for PL prediction in 4G Long Term Evolution (LTE) network was modified and optimized. Measured PL values were obtained and compared with the existing models in order to obtain the closest model to the measured data. The Okumura-Hata model as the closest to the measured values was modified using the loss exponent obtained for FUTO terrain and optimized for better performance using the developed autoregressive (AR) model. The measured data, the existing, modified and optimized AR [opt(AR m)] models were simulated using the MATLAB software. The performances of the existing and opt(AR m) models were evaluated using the root mean square error (RMSE). The results obtained show that the proposed opt(AR m) model is the best as compared to the existing models due to its lowest RMSE value, and thus it can be used to estimate PL for mobile radio signal in FUTO

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International Journal of Wireless and Microwave Technologies, 2021

This paper presents an improved hybrid Equal Gain Combiner-Maximal Ratio Combiner (EGC-MRC) diver... more This paper presents an improved hybrid Equal Gain Combiner-Maximal Ratio Combiner (EGC-MRC) diversity scheme in 5G millimeter wave (mm-wave) frequency. The term 5G mm-wave refers to the radio frequency spectrum between 24 and 100. The signal interference is a challenging task in 5G mm-wave frequency, and radio network suffer from co-channel and adjacent channel interference. 5G network deployment depends on large number of antennas, which resulted in signal interference. The conventional receiver's diversity techniques have high hardware complexity and are characterized by low performance. A new hybrid EGC-MRC diversity scheme was proposed as an improvement on the performance of existing MRC scheme. In achieving this, Probability Density Function (PDF) of the hybrid model was derived using the instantaneous Signal-to-Noise Ratio (SNR) obtained from the output of MRC and EGC diversity schemes. The performance of the developed model was evaluated using Outage Probability () and Processing time () at different SNR with number of paths. Simulation of the MRC, EGC and hybrid EGC-MRC models were carried out using MATLAB 2018a and the results compared. The output results showed that hybrid EGC-MRC performed better than EGC and MRC by having a lower and. This new model has the potential to mitigate network interference, multipath propagation, and hardware complexity in 5G mm-wave frequency. Therefore, the developed model can be deployed by network operators to solve signal interference in 5G network.

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International Journal of Wireless & Mobile Networks, 2021

This study was carried out to investigate the spectrum utilization of the licensed Radio Frequenc... more This study was carried out to investigate the spectrum utilization of the licensed Radio Frequency (RF) spectrum in Rumuokwuta, Port Harcourt. An outdoor measurement of spectrum occupancy was carried out in a high-rise building situated at Rumuokwuta urban area in Port Harcourt, Nigeria using RF explorer spectrum analyzer and a personal computer laptop system. Spectrum activities in the band of 240-960 MHz were monitored for 24 hours. The frequency band was subdivided into 24 sub bands each with a span size of 30 MHz. Scanning of bands was made efficient using a python script that scans a range, analyzed the frequencies and signal strengths for 112 data points, saves data in CSV file format, scans the next range until the 24 ranges were scanned. The process was repeated to achieve 15 iterations. With a noise floor of-110dBm, a threshold of-95dBm was used to determine the presence of signal, hence the spectrum occupancy of measured bands. Results showed that out of the 24 investigated sub bands; only one band was completely occupied with spectrum occupancy of 100%. 12 bands were partially occupied while 11 were completely free. The average spectrum occupancy for the whole band was obtained as 11.64%. This showed good location for dynamic spectrum access and cognitive radio deployment, especially in Television White Space (TVWS).

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International Journal of Wireless and Microwave Technologies, 2021

This paper focuses on Spread Spectrum technique and its interference mitigation feature as applie... more This paper focuses on Spread Spectrum technique and its interference mitigation feature as applied in wireless communication. With spread spectrum technology it is possible to implement the transmission of multiple signals over wider ranges of spectrum without resulting to interference from other signals transmitted over the same frequencies. It does this by rejecting any received signal that does not carry the proper code. Interference rejection, one of the several features of spread spectrum technology is a difficult concept to understand. It is therefore proper to x-ray this topic in a less complex manner so that it can be well understood by those who are not mathematically grounded. In view of this a further simplified approach in presenting this subject is necessary. A tutorial approach is used to simplify this subject for better understanding and how this feature is used in Code Division Multiple Access (CDMA) systems. To show how multipath interference rejection is achieved in CDMA systems simple equations and schematics were used. The discussions cover the method of code recognition at the receiver which serves as a technique for interference mitigation. The paper helps to understand the theory of code recognition in Spread Spectrum, and thus provides answer to the question on how does interference mitigation or rejection in spread spectrum works?

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International Journal of Electrical Engineering and Technology, 2021

This paper deals with valuating the experimental performance of 46MWh solar photovoltaic system w... more This paper deals with valuating the experimental performance of 46MWh solar photovoltaic system which was designed, developed, sized and installed at multicomplex building of health centre, Obodo Ahiara, in Ahiazu Mbaise local government area, Imo State, Nigeria for converting abundant sunlight natural energy resource directly to electricity. The performance characteristics of the modules are valuated experimentally in terms of their response variables open circuit voltage (Voc), maximum voltage Vmax, short circuit current Isc, maximum current Imax, maximum
power Pmax, and efficiency 𝜀 as a function of difference irradiance values of 400W/m2
, 450W/m2, 500W/m2and 600W/m2 for a period of 30 days in the month of January, 2018. These response variables are generally observed hourly to be directly proportional to irradiance with significant decrease in efficiency, Vmax, and Voc and Fill factor FF. Maximum efficiencies of 11.23% and 8.27% are achieved at irradiance of 500W/m2 for the module1 and module 2 respectively. The maximum power outputs obtained at irradiance of 500W/m2 are 15.39 W and 22.65 W representing 30.78% and 45.3% of the manufacturer’s power specifications for the PV module 1 and module 2 tested respectively. The hourly daily measured total and average temperatures vary from high values of 345.400C (43.180C), 310.100C(38.760C) and 306.000C(38.250C) on the 1st, 3rd and 4th days to low values of 272.400C(34.050C) and 290.500C(36.310C) on the 5th and 2nd days.

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Eximia Journal, 2022

Increasing security concerns in areas where insurgency persist, calls for reduced visitation of t... more Increasing security concerns in areas where insurgency persist, calls for reduced visitation of the farmers to their farms, consequently affecting produce. This calls for remote monitoring of the environmental weather and soil conditions of the farmland in order to trigger irrigation automatically. Traditional broadband systems used for remote monitoring of soil and environmental weather conditions require high cost and focuses on enabling high data rates per device and are not energy efficient. In this work, Long Range Wireless Area Network (LoRaWAN) has been presented, a new trend in the evolution of the wireless communication technologies to provide energy efficient system that requires no data cost for monitoring. In achieving this, BME280-Temperature, Humidity and Pressure Sensors, ESP32 LoRa transmitter and receiver modules were used. Arduino C++ programming language was used for the ESP32 controller. A wireless access point was established between the transmitter and receiver; and sensor-data was transmitted seamlessly from the transmitter to the receiver, updating every 10seconds. The result at the receiver visualized on the Organic Light Emitting Diodes (OLED) or via mobile phone at no data cost shows the Received Signal Strength Indicator (RSSI), Temperature, Pressure and Humidity values at real time. Automatic DC Sprinkler system triggered when the BME280 sensor threshold values for pressure and temperature were met.

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European Journal of Engineering and Technology Research, 2021

Many countries are faced with different challenges in the deployment of 5G mobile wireless commun... more Many countries are faced with different challenges in the deployment of 5G mobile wireless communication technology. These challenges have delayed the smooth rollout of this technology in these countries. Nigeria has its own issues that have hindered the implementation of this technology in the country. This paper discusses these challenges and suggestions made on what to do for the implementation of 5G technology. A survey was done by visiting and obtaining reports from two major players in the industry as well as understudying actions taken by other nations in tackling similar problems related to 5G network implementation. Based on the information gathered both from the industry and related literature some useful suggestions such as improved fiber infrastructure and relaxing regulatory barriers to encourage investors were made as a way forward for the full implementation and operation of the 5G technology in Nigeria.

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International Journal of Mechatronics, Electrical and Computer Technology, 2022

Human fault and recklessness of drivers especially in developing countries are mainly responsible... more Human fault and recklessness of drivers especially in developing countries are mainly responsible for numerous road traffic accidents recorded in those countries. Many of these road accidents have led to injuries and loss of lives. Technological advancement has led to the development of autonomous braking system to aid drivers in avoiding collision with another car or obstacle. This has been further advanced with the development of driverless vehicles. In this article, Proportional Integral Derivative (PID) and an Artificial Intelligence (AI) based on Neural Network (NN) model for Automatic Braking System (ABS) is proposed. The inputs to the network are the distance from vehicle to an obstruction and the velocity while the force applied on the brake to bring the vehicle to a halt without hitting the obstruction is the output. The simulation results for the two techniques show that the vehicle was able to stop at a good and acceptable distance before the obstacle and at minimal time. It is therefore reasonable to state that the PID and especially NN based ABS are excellent at providing robust and safe braking and can be implemented to good effect.

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This paper presents a study on the radiation characteristics of a small loop antenna. Loop antenn... more This paper presents a study on the radiation characteristics of a small loop antenna. Loop antenna, although structurally simple is a special type of wire antenna with the shape of a circle, square or rectangle. It can be small or large and its design challenging. Different studies have been made on small loop antennas. Here, the radiation characteristic is studied by carrying out a simple loop antenna design using the physical dimensions of both the wire conductor and antenna loop. The dimensions of the antenna were determined using Genetic algorithm (GA) technique which presented various options of choice. Radiation efficiency for each option was computed and results presented. Antenna parameters were also computed and presented. The radiation pattern obtained was based on the antenna conductor that yielded the highest computed radiation efficiency. This showed that small loop antenna produces high radiation efficiency if the conductor and loop dimensions are properly chosen.

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The performance of a CDMA1xEV-DO wireless network operating at a frequency of 876.76MHz in the ci... more The performance of a CDMA1xEV-DO wireless network operating at a frequency of 876.76MHz in the city of Port Harcourt, Nigeria was evaluated in his work. Several network performance challenges ranging from poor network coverage to overall quality of service degradation have been recently experienced by the network users. These obvious challenges attributed to finding the efficient method for the system upgrade. Field measurements were conducted in some selected urban areas in Port Harcourt such as Aba road, Ikwerre road and Liozu roadusing Agilent tool E6474 and ZTE 302 test phone at vehicular speed. The received signal strength (RSS) was gathered from the transceiver stations of Visafone with transmitting power of 27W, mounted on a steel tower with average height of 40m and mobile height of 1.5m.The measurements were conducted within the range of 100 to 1200 meters at an interval of 100m apart. The computed pathloss exponent and the standard deviation were obtained as 3.24 and 5.11d...

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2017 IEEE 3rd International Conference on Electro-Technology for National Development (NIGERCON), 2017

In this paper, an adapted cloud system using StackOps Distro Community Edition was designed for t... more In this paper, an adapted cloud system using StackOps Distro Community Edition was designed for the Electrical and Electronic Engineering (EEE) Department of the Federal University of Technology, Owerri. This is essential as there is need for readily available Information and Communication Technology services in the department. The current dependence on hard copy communication and individual purchase of key software needed for work and study by staff and students, makes the current situation inefficient and costly. Ubiquitous access to data, software, projects etc are vital, especially in academia. The adapted cloud system comprises of a private cloud deployed using StackOpsDistro Community Edition Cloud Software over a wired local area network and a public cloud hosted by WhoGoHost Hosting Service Provider. This was needed as the department does not have the funding and resources to create customized software which are already available online. Secondly the private cloud deployed has limited availability due to unstable power supply while the public cloud guarantees round-the-clock availability of cloud resources. Also security issues facing public cloud are mitigated by keeping confidential documents on the private cloud. Cloud access is solely on username and password authentication against a preloaded database. Cloud client devices such as internet-enabled mobile phones, tablets, laptops and desktops could be used to access the system provided a web browser is installed. The EEE Adapted Cloud System has a tested average response time of 476milliseconds, above 90% availability and 0% packet loss.

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2017 IEEE 3rd International Conference on Electro-Technology for National Development (NIGERCON), 2017

The mobile communication industry since its inception has been confronted with the problem of mee... more The mobile communication industry since its inception has been confronted with the problem of meeting the ever increasing demand for higher data rates as well as quality of service (QoS) which may be affected by channel obstruction, signal attenuation and frequency assignment in network planning. This paper is basedon autoregressive modeling of mobile channel in LTE network in which the propagation path loss for locations in Ibadan City was investigated. Using drive test, data obtained were optimized using Auto-Regressive Adaptive inertiaweight(ARAW). Simulation was carried out using MATLAB R2014a. The average measured losses obtained were compared with the corresponding results obtained using Okumura-Hata, COST 231, Ericsson 999 and ECC-33 models. The validation of model was performed with error metrics such as Absolute Mean Percentage Error (AMPE) and Root Mean Square Error (RMSE). The results obtained indicated that ARaw optimized model gave better result which is suitable for ce...

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2017 IEEE 3rd International Conference on Electro-Technology for National Development (NIGERCON), 2017

This paper derived and established a standard and compact ‘Array Factor’ for Log Periodic Circula... more This paper derived and established a standard and compact ‘Array Factor’ for Log Periodic Circular-Loop Antennas using Magnetic Vector Potential approach. It manipulated the vector potential of the circular-loop antenna array by assuming a negligible width for the circular wires, as such the current flowing through the wire is assumedly constant, that is Ι<inf>φ</inf>=Ι<inf>0</inf>. The result of this work generated a unique array factor that is an exact of that of the log periodic dipole array antennas.

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Radio electronics and communications systems, 2022

Path Loss (PL) is a factor that contributes to signal impairment in a wireless channel and can be... more Path Loss (PL) is a factor that contributes to signal impairment in a wireless channel and can be predicted using empirical models such as Okumura-Hata, Egli, COST, and ECC-33. These models are known to be inaccurate when used in areas different from where they are meant for. In this paper an empirical model suitable for PL prediction in 4G Long Term Evolution (LTE) network was modified and optimized. Measured PL values were obtained and compared with the existing models in order to obtain the closest model to the measured data. The Okumura-Hata model as the closest to the measured values was modified using the loss exponent obtained for FUTO terrain and optimized for better performance using the developed autoregressive (AR) model. The measured data, the existing, modified and optimized AR [opt(AR m)] models were simulated using the MATLAB software. The performances of the existing and opt(AR m) models were evaluated using the root mean square error (RMSE). The results obtained show that the proposed opt(AR m) model is the best as compared to the existing models due to its lowest RMSE value, and thus it can be used to estimate PL for mobile radio signal in FUTO

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Radioelectronics and Communications Systems, 2022

Path Loss (PL) is a factor that contributes to signal impairment in a wireless channel and can be... more Path Loss (PL) is a factor that contributes to signal impairment in a wireless channel and can be predicted using empirical models such as Okumura-Hata, Egli, COST, and ECC-33. These models are known to be inaccurate when used in areas different from where they are meant for. In this paper an empirical model suitable for PL prediction in 4G Long Term Evolution (LTE) network was modified and optimized. Measured PL values were obtained and compared with the existing models in order to obtain the closest model to the measured data. The Okumura-Hata model as the closest to the measured values was modified using the loss exponent obtained for FUTO terrain and optimized for better performance using the developed autoregressive (AR) model. The measured data, the existing, modified and optimized AR [opt(AR m)] models were simulated using the MATLAB software. The performances of the existing and opt(AR m) models were evaluated using the root mean square error (RMSE). The results obtained show that the proposed opt(AR m) model is the best as compared to the existing models due to its lowest RMSE value, and thus it can be used to estimate PL for mobile radio signal in FUTO

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International Journal of Wireless and Microwave Technologies, 2022

5G Heterogeneous network is characterized with small cells in close proximity with one another wh... more 5G Heterogeneous network is characterized with small cells in close proximity with one another which in most cases are active even at low traffic load periods. Such scenarios lead to unnecessary large energy consumption and co-frequency interference. This large energy consumption and interference in 5G heterogeneous networks have been an issue widely discussed in several technical literature. Different and attractive techniques on energy management have been investigated and proposed. All these have been in seeking ways of minimizing or reducing energy consumption in mobile networks. In this study the on/off and sleep-mode schemes as energy management techniques have been reviewed with the major aim of identifying weak areas of both techniques and suggesting ways which will be useful for further research works in the future. In doing so recent literature on the subject matter were consulted. The on/off and sleep-mode schemes involve switching processes which result to loss of data and information during change of state. Quality of service issues arising from incomplete or proper switching process and unnecessary delay perceived by the users were observed as major concern for both schemes. For further work, amongst other suggestions, it is suggested that the time needed between system switching command and switching operations be considered as an important factor in eliminating switching problems which will positively affect the overall quality of service.

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International Journal of Wireless and Microwave Technologies, 2021

Bookmarks Related papers MentionsView impact

International Journal of Wireless & Mobile Networks, 2021

This study was carried out to investigate the spectrum utilization of the licensed Radio Frequenc... more This study was carried out to investigate the spectrum utilization of the licensed Radio Frequency (RF) spectrum in Rumuokwuta, Port Harcourt. An outdoor measurement of spectrum occupancy was carried out in a high-rise building situated at Rumuokwuta urban area in Port Harcourt, Nigeria using RF explorer spectrum analyzer and a personal computer laptop system. Spectrum activities in the band of 240-960 MHz were monitored for 24 hours. The frequency band was subdivided into 24 sub bands each with a span size of 30 MHz. Scanning of bands was made efficient using a python script that scans a range, analyzed the frequencies and signal strengths for 112 data points, saves data in CSV file format, scans the next range until the 24 ranges were scanned. The process was repeated to achieve 15 iterations. With a noise floor of - 110dBm, a threshold of -95dBm was used to determine the presence of signal, hence the spectrum occupancy of measured bands. Results showed that out of the 24 investig...

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The performance of a CDMA1xEV-DO wireless network operating at a frequency of 876.76MHz in the ci... more The performance of a CDMA1xEV-DO wireless network operating at a frequency of 876.76MHz in the city of Port Harcourt, Nigeria was evaluated in his work. Several network performance challenges ranging from poor network coverage to overall quality of service degradation have been recently experienced by the network users. These obvious challenges attributed to finding the efficient method for the system upgrade. Field measurements were conducted in some selected urban areas in Port Harcourt such as Aba road, Ikwerre road and Liozu roadusing Agilent tool E6474 and ZTE 302 test phone at vehicular speed. The received signal strength (RSS) was gathered from the transceiver stations of Visafone with transmitting power of 27W, mounted on a steel tower with average height of 40m and mobile height of 1.5m.The measurements were conducted within the range of 100 to 1200 meters at an interval of 100m apart. The computed pathloss exponent and the standard deviation were obtained as 3.24 and 5.11d...

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European Journal of Engineering Research and Science, 2020

This paper focuses on the Performance Improvement of a Direction Finding System Antenna Using M... more This paper focuses on the Performance
Improvement of a Direction Finding System Antenna Using
Method of Moment (MoM) Approach. The work is developed
to provide an approximate current distribution for a direction
finding system antenna by employing the use of Method of
Moment on an array of Yagi-uda antenna. The parameters of
the experimental antenna are derived and analyzed via
Magnetic Vector Potential (MVP) operator. The accurate
current flowing through the radiating elements of the direction
finding system is analyzed using combination of Method of
Moment technique and Magnetic Vector Potential (MVP)
operator. This helps to avoid the detection of false alarms and
inability of the system to detect remote targets. A typical
direction finding system Yagi antenna is designed and operated
at a frequency range of 0.6- 0.8 GHz. The antenna has a single
reflector, an active (driven) element and three (3) parasitic
directors. The antenna parameters are simulated using
MatLab R2010a software tool. The average pointing vector of
the designed Yagi antenna was obtained as 3.73watt per square
metre, and Radiation Intensity value of about 9.400 coulomb
per kilogram. The simulation results indicate an appreciable
increase in directivity of 9.03dBi, an enhanced directive gain
compared to that of the equivalent dipole antenna of 1.76dBi,
signifying 7.27dBi enhancement.

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Radioelectronics and Communications Systems, 2022

Path Loss (PL) is a factor that contributes to signal impairment in a wireless channel and can be... more Path Loss (PL) is a factor that contributes to signal impairment in a wireless channel and can be predicted using empirical models such as Okumura-Hata, Egli, COST, and ECC-33. These models are known to be inaccurate when used in areas different from where they are meant for. In this paper an empirical model suitable for PL prediction in 4G Long Term Evolution (LTE) network was modified and optimized. Measured PL values were obtained and compared with the existing models in order to obtain the closest model to the measured data. The Okumura-Hata model as the closest to the measured values was modified using the loss exponent obtained for FUTO terrain and optimized for better performance using the developed autoregressive (AR) model. The measured data, the existing, modified and optimized AR [opt(AR m)] models were simulated using the MATLAB software. The performances of the existing and opt(AR m) models were evaluated using the root mean square error (RMSE). The results obtained show that the proposed opt(AR m) model is the best as compared to the existing models due to its lowest RMSE value, and thus it can be used to estimate PL for mobile radio signal in FUTO

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International Journal of Wireless and Microwave Technologies, 2021

This paper presents an improved hybrid Equal Gain Combiner-Maximal Ratio Combiner (EGC-MRC) diver... more This paper presents an improved hybrid Equal Gain Combiner-Maximal Ratio Combiner (EGC-MRC) diversity scheme in 5G millimeter wave (mm-wave) frequency. The term 5G mm-wave refers to the radio frequency spectrum between 24 and 100. The signal interference is a challenging task in 5G mm-wave frequency, and radio network suffer from co-channel and adjacent channel interference. 5G network deployment depends on large number of antennas, which resulted in signal interference. The conventional receiver's diversity techniques have high hardware complexity and are characterized by low performance. A new hybrid EGC-MRC diversity scheme was proposed as an improvement on the performance of existing MRC scheme. In achieving this, Probability Density Function (PDF) of the hybrid model was derived using the instantaneous Signal-to-Noise Ratio (SNR) obtained from the output of MRC and EGC diversity schemes. The performance of the developed model was evaluated using Outage Probability () and Processing time () at different SNR with number of paths. Simulation of the MRC, EGC and hybrid EGC-MRC models were carried out using MATLAB 2018a and the results compared. The output results showed that hybrid EGC-MRC performed better than EGC and MRC by having a lower and. This new model has the potential to mitigate network interference, multipath propagation, and hardware complexity in 5G mm-wave frequency. Therefore, the developed model can be deployed by network operators to solve signal interference in 5G network.

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International Journal of Wireless & Mobile Networks, 2021

This study was carried out to investigate the spectrum utilization of the licensed Radio Frequenc... more This study was carried out to investigate the spectrum utilization of the licensed Radio Frequency (RF) spectrum in Rumuokwuta, Port Harcourt. An outdoor measurement of spectrum occupancy was carried out in a high-rise building situated at Rumuokwuta urban area in Port Harcourt, Nigeria using RF explorer spectrum analyzer and a personal computer laptop system. Spectrum activities in the band of 240-960 MHz were monitored for 24 hours. The frequency band was subdivided into 24 sub bands each with a span size of 30 MHz. Scanning of bands was made efficient using a python script that scans a range, analyzed the frequencies and signal strengths for 112 data points, saves data in CSV file format, scans the next range until the 24 ranges were scanned. The process was repeated to achieve 15 iterations. With a noise floor of-110dBm, a threshold of-95dBm was used to determine the presence of signal, hence the spectrum occupancy of measured bands. Results showed that out of the 24 investigated sub bands; only one band was completely occupied with spectrum occupancy of 100%. 12 bands were partially occupied while 11 were completely free. The average spectrum occupancy for the whole band was obtained as 11.64%. This showed good location for dynamic spectrum access and cognitive radio deployment, especially in Television White Space (TVWS).

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International Journal of Wireless and Microwave Technologies, 2021

This paper focuses on Spread Spectrum technique and its interference mitigation feature as applie... more This paper focuses on Spread Spectrum technique and its interference mitigation feature as applied in wireless communication. With spread spectrum technology it is possible to implement the transmission of multiple signals over wider ranges of spectrum without resulting to interference from other signals transmitted over the same frequencies. It does this by rejecting any received signal that does not carry the proper code. Interference rejection, one of the several features of spread spectrum technology is a difficult concept to understand. It is therefore proper to x-ray this topic in a less complex manner so that it can be well understood by those who are not mathematically grounded. In view of this a further simplified approach in presenting this subject is necessary. A tutorial approach is used to simplify this subject for better understanding and how this feature is used in Code Division Multiple Access (CDMA) systems. To show how multipath interference rejection is achieved in CDMA systems simple equations and schematics were used. The discussions cover the method of code recognition at the receiver which serves as a technique for interference mitigation. The paper helps to understand the theory of code recognition in Spread Spectrum, and thus provides answer to the question on how does interference mitigation or rejection in spread spectrum works?

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International Journal of Electrical Engineering and Technology, 2021

This paper deals with valuating the experimental performance of 46MWh solar photovoltaic system w... more This paper deals with valuating the experimental performance of 46MWh solar photovoltaic system which was designed, developed, sized and installed at multicomplex building of health centre, Obodo Ahiara, in Ahiazu Mbaise local government area, Imo State, Nigeria for converting abundant sunlight natural energy resource directly to electricity. The performance characteristics of the modules are valuated experimentally in terms of their response variables open circuit voltage (Voc), maximum voltage Vmax, short circuit current Isc, maximum current Imax, maximum
power Pmax, and efficiency 𝜀 as a function of difference irradiance values of 400W/m2
, 450W/m2, 500W/m2and 600W/m2 for a period of 30 days in the month of January, 2018. These response variables are generally observed hourly to be directly proportional to irradiance with significant decrease in efficiency, Vmax, and Voc and Fill factor FF. Maximum efficiencies of 11.23% and 8.27% are achieved at irradiance of 500W/m2 for the module1 and module 2 respectively. The maximum power outputs obtained at irradiance of 500W/m2 are 15.39 W and 22.65 W representing 30.78% and 45.3% of the manufacturer’s power specifications for the PV module 1 and module 2 tested respectively. The hourly daily measured total and average temperatures vary from high values of 345.400C (43.180C), 310.100C(38.760C) and 306.000C(38.250C) on the 1st, 3rd and 4th days to low values of 272.400C(34.050C) and 290.500C(36.310C) on the 5th and 2nd days.

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Eximia Journal, 2022

Increasing security concerns in areas where insurgency persist, calls for reduced visitation of t... more Increasing security concerns in areas where insurgency persist, calls for reduced visitation of the farmers to their farms, consequently affecting produce. This calls for remote monitoring of the environmental weather and soil conditions of the farmland in order to trigger irrigation automatically. Traditional broadband systems used for remote monitoring of soil and environmental weather conditions require high cost and focuses on enabling high data rates per device and are not energy efficient. In this work, Long Range Wireless Area Network (LoRaWAN) has been presented, a new trend in the evolution of the wireless communication technologies to provide energy efficient system that requires no data cost for monitoring. In achieving this, BME280-Temperature, Humidity and Pressure Sensors, ESP32 LoRa transmitter and receiver modules were used. Arduino C++ programming language was used for the ESP32 controller. A wireless access point was established between the transmitter and receiver; and sensor-data was transmitted seamlessly from the transmitter to the receiver, updating every 10seconds. The result at the receiver visualized on the Organic Light Emitting Diodes (OLED) or via mobile phone at no data cost shows the Received Signal Strength Indicator (RSSI), Temperature, Pressure and Humidity values at real time. Automatic DC Sprinkler system triggered when the BME280 sensor threshold values for pressure and temperature were met.

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European Journal of Engineering and Technology Research, 2021

Many countries are faced with different challenges in the deployment of 5G mobile wireless commun... more Many countries are faced with different challenges in the deployment of 5G mobile wireless communication technology. These challenges have delayed the smooth rollout of this technology in these countries. Nigeria has its own issues that have hindered the implementation of this technology in the country. This paper discusses these challenges and suggestions made on what to do for the implementation of 5G technology. A survey was done by visiting and obtaining reports from two major players in the industry as well as understudying actions taken by other nations in tackling similar problems related to 5G network implementation. Based on the information gathered both from the industry and related literature some useful suggestions such as improved fiber infrastructure and relaxing regulatory barriers to encourage investors were made as a way forward for the full implementation and operation of the 5G technology in Nigeria.

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International Journal of Mechatronics, Electrical and Computer Technology, 2022

Human fault and recklessness of drivers especially in developing countries are mainly responsible... more Human fault and recklessness of drivers especially in developing countries are mainly responsible for numerous road traffic accidents recorded in those countries. Many of these road accidents have led to injuries and loss of lives. Technological advancement has led to the development of autonomous braking system to aid drivers in avoiding collision with another car or obstacle. This has been further advanced with the development of driverless vehicles. In this article, Proportional Integral Derivative (PID) and an Artificial Intelligence (AI) based on Neural Network (NN) model for Automatic Braking System (ABS) is proposed. The inputs to the network are the distance from vehicle to an obstruction and the velocity while the force applied on the brake to bring the vehicle to a halt without hitting the obstruction is the output. The simulation results for the two techniques show that the vehicle was able to stop at a good and acceptable distance before the obstacle and at minimal time. It is therefore reasonable to state that the PID and especially NN based ABS are excellent at providing robust and safe braking and can be implemented to good effect.

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This paper presents a study on the radiation characteristics of a small loop antenna. Loop antenn... more This paper presents a study on the radiation characteristics of a small loop antenna. Loop antenna, although structurally simple is a special type of wire antenna with the shape of a circle, square or rectangle. It can be small or large and its design challenging. Different studies have been made on small loop antennas. Here, the radiation characteristic is studied by carrying out a simple loop antenna design using the physical dimensions of both the wire conductor and antenna loop. The dimensions of the antenna were determined using Genetic algorithm (GA) technique which presented various options of choice. Radiation efficiency for each option was computed and results presented. Antenna parameters were also computed and presented. The radiation pattern obtained was based on the antenna conductor that yielded the highest computed radiation efficiency. This showed that small loop antenna produces high radiation efficiency if the conductor and loop dimensions are properly chosen.

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The performance of a CDMA1xEV-DO wireless network operating at a frequency of 876.76MHz in the ci... more The performance of a CDMA1xEV-DO wireless network operating at a frequency of 876.76MHz in the city of Port Harcourt, Nigeria was evaluated in his work. Several network performance challenges ranging from poor network coverage to overall quality of service degradation have been recently experienced by the network users. These obvious challenges attributed to finding the efficient method for the system upgrade. Field measurements were conducted in some selected urban areas in Port Harcourt such as Aba road, Ikwerre road and Liozu roadusing Agilent tool E6474 and ZTE 302 test phone at vehicular speed. The received signal strength (RSS) was gathered from the transceiver stations of Visafone with transmitting power of 27W, mounted on a steel tower with average height of 40m and mobile height of 1.5m.The measurements were conducted within the range of 100 to 1200 meters at an interval of 100m apart. The computed pathloss exponent and the standard deviation were obtained as 3.24 and 5.11d...

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2017 IEEE 3rd International Conference on Electro-Technology for National Development (NIGERCON), 2017

In this paper, an adapted cloud system using StackOps Distro Community Edition was designed for t... more In this paper, an adapted cloud system using StackOps Distro Community Edition was designed for the Electrical and Electronic Engineering (EEE) Department of the Federal University of Technology, Owerri. This is essential as there is need for readily available Information and Communication Technology services in the department. The current dependence on hard copy communication and individual purchase of key software needed for work and study by staff and students, makes the current situation inefficient and costly. Ubiquitous access to data, software, projects etc are vital, especially in academia. The adapted cloud system comprises of a private cloud deployed using StackOpsDistro Community Edition Cloud Software over a wired local area network and a public cloud hosted by WhoGoHost Hosting Service Provider. This was needed as the department does not have the funding and resources to create customized software which are already available online. Secondly the private cloud deployed has limited availability due to unstable power supply while the public cloud guarantees round-the-clock availability of cloud resources. Also security issues facing public cloud are mitigated by keeping confidential documents on the private cloud. Cloud access is solely on username and password authentication against a preloaded database. Cloud client devices such as internet-enabled mobile phones, tablets, laptops and desktops could be used to access the system provided a web browser is installed. The EEE Adapted Cloud System has a tested average response time of 476milliseconds, above 90% availability and 0% packet loss.

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2017 IEEE 3rd International Conference on Electro-Technology for National Development (NIGERCON), 2017

The mobile communication industry since its inception has been confronted with the problem of mee... more The mobile communication industry since its inception has been confronted with the problem of meeting the ever increasing demand for higher data rates as well as quality of service (QoS) which may be affected by channel obstruction, signal attenuation and frequency assignment in network planning. This paper is basedon autoregressive modeling of mobile channel in LTE network in which the propagation path loss for locations in Ibadan City was investigated. Using drive test, data obtained were optimized using Auto-Regressive Adaptive inertiaweight(ARAW). Simulation was carried out using MATLAB R2014a. The average measured losses obtained were compared with the corresponding results obtained using Okumura-Hata, COST 231, Ericsson 999 and ECC-33 models. The validation of model was performed with error metrics such as Absolute Mean Percentage Error (AMPE) and Root Mean Square Error (RMSE). The results obtained indicated that ARaw optimized model gave better result which is suitable for ce...

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2017 IEEE 3rd International Conference on Electro-Technology for National Development (NIGERCON), 2017

This paper derived and established a standard and compact ‘Array Factor’ for Log Periodic Circula... more This paper derived and established a standard and compact ‘Array Factor’ for Log Periodic Circular-Loop Antennas using Magnetic Vector Potential approach. It manipulated the vector potential of the circular-loop antenna array by assuming a negligible width for the circular wires, as such the current flowing through the wire is assumedly constant, that is Ι<inf>φ</inf>=Ι<inf>0</inf>. The result of this work generated a unique array factor that is an exact of that of the log periodic dipole array antennas.

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Robotic vehicle would in future serve in different capacities in assisting handicapped and ventur... more Robotic vehicle would in future serve in different capacities in assisting handicapped and venturing into places that are not safe for human beings. Research thus far was void of a detailed analysis of gesture angular displacement to speed relationship and most designs used RF-modules as a medium of wireless communication. This work attempts to design a robotic vehicle controlled by five palm gestures and exhaustively study its performance. To achieve this gesture sensitive transmitter circuit was designed for the palm glove and a receiver circuit for the robotic vehicle. Transmission medium was via a Bluetooth module and an ARDUINO microcontroller was programmed using C-language to control both transmitter and receiver. The robotic vehicle was successfully designed and its performance in the two modes were analysed based on speed, response time and blind spot. The vehicle operates on autonomous and semi-autonomous mode. Results gotten showed that in the semi-autonomous mode (gesture mode), tilting palm angle from 0-40 degree, made the unmanned automatic vehicle (UAV) move at minimal speed of 0.55m/s. While medium speed of 0.63m/s and maximum speed of 0.91m/s were obtained at 40-60 degrees and 70 to 90 degrees respectively. In its autonomous mode the speed was 0.97m/s. These result buttress the Index Terms-robotic vehicles, UAV, hand gestures, automatic control, accelerometer, tilt angle.

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