Browsing by Author "Agubor, C. K."

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    A practical guide to site selection for communication antennas and their support structures in Nigeria
    (SAVAP International, 2013-01) Agubor, C. K.; Ndinechi, M. C.; Opara, R. O.
    Radio broadcasting and telecommunication transmitter stations should have their antennas properly positioned to make them capable of providing the required services. Suitable location of antenna structure will enhance signal clarity, wider coverage area and satisfactory reception of radiated signal. In most cases, engineering considerations in the determination of a station’s performance are treated analytically. However, it is important to know that the ability to serve large audience effectively and at the same time achieve wider signal coverage are greatly affected by the excellence of the transmitter location and its selection must be governed or influenced by experience with intangibles not subject to mathematical calculations. Field survey method was adopted by which information from the major radio and wireless Operators in the country was obtained. The paper therefore focuses on the various factors guiding the selection of suitable transmitter sites. It also presents a step-by-step guide and some important considerations to be taken into account from the planning to the site-acquisition stages. It recommends colocation of infrastructures which is an option not yet attractive to Service Providers in Nigeria.
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    A survey on the availability of TV white spaces in Eastern Nigeria
    (U. P., 2015) Atimati, E. E.; Ezema, L. S.; Ezeh, G. N.; Iwuchukwu, U. C.; Agubor, C. K.
    Effective utilization of future wireless communication systems such as the TV White spaces depend largely on the availability of free unused spectrum within the 470 – 860MHz UHF band. The paper, analyses the effectiveness of TV White space for last mile delivery of broadband based on spectral availability. The survey was carried out on a spectral range of 470 – 870MHz within the study area, using a RF spectrum analyser and the readings were presented using graph plots through the aid of Touchstone PC spectrum analyser. Fixed measurement was adopted and two (2) sites were chosen to take measurement. The results revealed that, 64% of the 50 channels surveyed were dormant. The degree of occupancy was found to be very low, thus providing for unused spectra spaces within the UHF frequency band which can be used to provide broadband services in sparsely populated rural areas; where data rate could be compromised for range at zero or low cost for acquiring operating spectral license
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    An evaluation of hand trajectory gesture controlled vehicular robot
    (Nigeria Consltants' Network (CN), 2021) Atimati, E. E.; Ezema, Longinus. S.; Okafor, K. C.; Achumba, I. E.; Ifediora, E. C.; Agubor, C. K.
    Vehicular robotics (VRs) is an emerging field in Mechatronics application that offers numerous benefits to assisted living systems, exploits in unsafe terrains, agricultural harvesting, and manufacturing automation, among others. The absence of gesture angular displacement to speed relationship remains unresolved in literature. Existing systems controlled by hand gesture uses Radio Frequency (RF) module as a medium of wireless communication. In this paper, a reengineered VR controlled by five palm gestures is implemented and evaluated. An accelerometer-powered transmitter circuitry for the palm glove is realized while integrating Bluetooth spectrum at the VR receiver for wireless signalling. C+ constructs are introduced for end-to-end control between the transmitter and receiver. Performance assessment carried out on actual speed, response time and a blind spot in both autonomous and semi autonomous modes provided satisfactory insights. It is observed that in semi-autonomous mode (gesture mode), under tilting palm angle ranged 0-40 degrees, a minimum speed of 0.55m/s was observed. A medium speed of 0.63m/s and a maximum speed of 0.91m/s are obtained at 40 to 60 degrees and 70 to 90 degrees respectively. Furthermore, the autonomous mode offered a speed of 0.97m/s.
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    Comparative analysis of multiple and single antenna applications in mobile wireless communication
    (SAVAP International, 2014) Agubor, C. K.; Ndinechi, M. C.; Chukwudebe, G. A.; Opara, F. K.
    The performance of multiple-antenna and single antenna systems as applicable in mobile wireless communication are compared. The method applied involves matrix computation based on the system model. The expressions derived were used to evaluate the system performance with zero-forcing (ZF) equalizer at the receiver. MATLAB Toolbox version 7.0 was used to carry out error performance simulation for the different transmitting and receiving antenna configurations in a Raleigh fading environment. The result showed in terms of BER performance that multiple antenna technique is capable of combating multi-path effects due to the low error rate they exhibited. The diversity modes employed by the multiple antennas were also analysed by comparing their / (Energy per bit to noise power spectral density ratio). Transmit diversity technique with multiple antennas at the base station and a single antenna at the remote end was further shown to be a better candidate for the next generation of wireless communication than the single-input single-output system.
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    Design and implementation of a simple HMC6352 2-Axis-MR digital compass
    (U. P., 2016-03) Agubor, C. K.; Ezeh, G. N.; Olubiwe, M.; Nosiri, O. C.
    This paper deals with the design and implementation of a simple HMC6352 2-axis digital compass.Most compasses have been of the analogue type with magnetic needles as pointers. Replacing the “old” magnetic needle compass or the gyrocompass by an electronic solution offers advantages like having a solid-state component without moving parts and the ease of interfacing with other electronic systems. In this work, the aim is to design and implement a digital compass. To realize this, we made use of HMC6352 which is a 2-axis MR (magneto-resistive) sensor from Honeywell, Arduino Uno board with an onboard ATmega328 microcontroller chip, and a 16x2 character Liquid Crystal Display (LCD).We adopted the magneto-resistive (MR) technology as compared to flux-gate sensors common in most electronic compasses which has the disadvantage of making the device bulky. The trial test carried out with the completed HMC6352 digital compass showed a reading of 232.8 degrees West indicating its effectiveness in direction finding
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    Optimal design and fabrication of a wideband antenna for terrestrial DTV reception
    (U. P., 2016-10) Agubor, C. K.; Onwumere, C.
    Optimal design and fabrication of a wideband antenna for terrestrial digital TV (DTV) reception is presented in this paper. Reception of poor digital TV (DTV) signal using Yagi antennas supplied by cable providers in some suburban and rural areas in Nigeria has been a major concern to subscribers. This problem could be solved by the use of high gain antennas such as the one presented in this paper. In developing this antenna, NBS 688 technical notes and antenna design curves were applied and the resulting antenna estimate was modeled, simulated and optimized with 4NEC2 antenna design software. Optimal design verification was achieved using EZNEC v.6.0 antenna modeler. On testing after fabrication, received signal strength was 60dB compared to 45dB obtained with the service provider’s conventional Yagi antenna in position. A better picture clarity was observed owing to the15dB increase in signal level.
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    Techniques in performance improvment of mobile wireless communication systems-A review
    (Progressive Academic Publishing, UK, 2015) Agubor, C. K.; Nosiri, O. C.; Ononiwu, G. C.; Atimati, E. E.; Onyishi, D. U.
    Mobile wireless communication providers are expected by their numerous subscribers to provide network that can allow higher data rates, and good voice quality. However, this may be restricted due to some technical problems such as limited availability of radio frequency spectrum, bandwidth, channel capacity, geographical areas and transmission problems caused by various factors like fading and multipath distortion. All these lead to overall system performance degradation. This has led to various studies on how improvement on the performance of wireless communication can be realized using different techniques. This paper is a review of some scholarly works on this subject. To achieve this some recent scholarly articles were accessed online and their findings were highlighted. It was observed that all the articles reviewed had results drawn only from theoretical analysis. Based on this, one of the recommendations is that theoretical analysis should be supported with data obtained from carrying out RF measurements in the field where possible